What is included in the locksmith assembly work. The main types of work and their purpose. performing locksmith and fitter-assembly works

Fitting and assembly work. Connection types

All types of connections of parts used in metalwork and assembly work are divided into two main groups: detachable and one-piece. Detachable connections are those that can be disassembled into their component parts. This group includes threaded, keyed, splined, pin and wedge connections. One-piece, respectively, those connections, the disassembly of which is possible only with the destruction of the fastening or the parts themselves. This group includes press, riveting, welded and adhesive joints.

Assembly of threaded connections

When trying to disassemble any mechanism or plumbing structure, whether it is the engine of a washing machine or an object of plumbing equipment, you will notice that most of all the joints of the parts are threaded. And this is not accidental: threaded connections are simple, reliable, interchangeable, and easy to adjust.

The assembly process of any threaded connection includes the following operations: installation of parts, baiting, screwing, tightening, sometimes tightening, if necessary, installation of locking parts and devices that prevent self-unscrewing.

When baiting, the part to be screwed must be brought to the threaded hole until the axes coincide and screwed into the thread by 2-3 threads. Anyone who has worked with small screws knows how inconvenient it can be to hold a screw in hard-to-reach places, such as from below. Professionals in such cases use magnetic and other special screwdrivers. But if they are not there, you should not despair and curse the stubborn screw with strong words, the problem can be solved with the help of a simple device that is easily made in just a few seconds. From a thin soft wire, you need to make a small hook and support the screw with it until it enters the threaded hole for several threads. Then you just need to pull on the wire - the loop will open and release the screw for further screwing with the tool.

After baiting, an assembly tool (wrench or screwdriver) is installed on the part and rotational movements are imparted to it (screwed). Screwing is completed by tightening, which creates immobility of the connection.

Tightening is performed when the part is fastened with several bolts (screws). For example, when attaching the cylinder head (in a car engine), the bolts are screwed in without pre-tightening, and after they are all installed, they are tightened. This is carried out in a certain order - according to the so-called spiral method (Fig. 50).

Rice. 50. Scheme of a possible sequence of tightening (tightening) of bolts (screws, nuts).

Threaded connections in mechanisms that are subjected to a pulsating load (vibration) during operation often unscrew themselves, which can cause an accident. Therefore, when assembling such mechanisms, they resort to locking threaded connections.

The simplest, fairly reliable and not requiring any special devices locking method is locking with a lock nut. It is screwed on after tightening the main fixing nut and tightened until it is in full contact with its end. The locking mechanism with this method is based on an increase in the friction surfaces in the thread and on the surfaces of the nuts.

Locking with lock washers is also widespread (Fig. 51).

Rice. 51. Ways of locking threaded connections: a - lock washer; b - stopper; c - wire; d - welding or punching.

Such a washer has either a nose, which is bent to the edge of the nut after it is tightened, or a foot, which is inserted into a specially drilled hole in the part body. Screws (bolts) with open heads can be locked with wire. Holes in the heads of screws (bolts) for wire in this case are drilled before they are installed in the assembly. The wire should be inserted into the holes in such a way that the tension of its ends creates a screwing moment.

Locking by welding or punching, in fact, turns a detachable connection into a one-piece.

Quite often, threaded connections use studs, which, unlike a bolt or screw, do not have a head. In order to ensure a tight fit of the stud into the body of the part, one of the proposed methods can be used: the stud tension is formed due to thread run-out (see the chapter on external threading) or is provided with a tight thread with interference along the average diameter of the turns. If the body of the part is made of a material less durable than the stud, then a spiral insert made of rhombic steel wire is used: it is inserted into the thread of the part body before the stud is screwed in. This method not only increases the strength and wear resistance of the connection (due to an increase in the surface of the thread cut in the body part), but also contributes to a tight fit of the stud. To form a sealed, hydro-tight connection, a gasket made of an easily deformable material (copper-asbestos, paronite, etc.) is placed between the parts to be joined.

In some cases, it is required to obtain a connection of special strength, which cannot be achieved using ordinary low-grade metal bolts, since they simply break under large transverse loads. Buying special high-strength bolts is expensive, and you can’t always find them in stores. In such cases, it is possible to apply an adhesive layer of epoxy resin on the surfaces of the parts that will be in contact before assembly. The connection will turn out to be very strong even when using ordinary cheap bolts.

Assembly of keyed-spline connections

Another type of fixed detachable connections are keyed-slotted, which are formed by rods - dowels. Keyed connections are mainly used in mechanisms for torque transmission. Depending on the load on such connections and the operating conditions of the mechanism, wedge, prismatic and segment keys are used (Fig. 52).

Rice. 52. Varieties of keyed connections: a - wedge key.

Rice. 52 (continued). Types of key connections: b - feather key; in - segment key; g - slotted; d - pin.

Rice. 52 (continued). Types of keyed connections: e - correctly assembled connection; g - defect of the increased gap; h - defect from misalignment of the axis of the keyway.

As a rule, such a connection consists of a shaft, a key and a wheel or bushing.

A type of keyway connection is spline, when the key is one with the shaft. Due to the fact that not three, but two parts are involved in this connection, the connection is more accurate.

When assembling keyed connections, a pin can be used instead of a key. The pin connection is more technologically advanced (which is ensured by the interchangeability of parts), but requires additional processing: in the female part and on the shaft, it is necessary to jointly drill and unfold a hole for the pin with a conical reamer.

The assembly sequence of the keyed connection is as follows: the shaft is fixed in a vice, a key is installed in the groove of the shaft and the female part is put on. In this case, the connection of the key with the shaft must be tight (the key is installed in the groove of the shaft with an interference fit), while the key is installed more freely in the groove of the hub.

When mounting the female part (wheels, bushings, etc.) on the shaft, it is necessary to ensure that the axes of the shaft and the part coincide. Incorrect keying leads to deformation and destruction of the key. The main reason for such a defect is the increased clearance or misalignment of the keyway axis. In order to avoid joint defects, the groove is adjusted by scraping, and the dimensions of the grooves and keys are adjusted, and the misalignment of the axes is controlled.

Soldered connections. Tinning

Soldering allows you to combine elements from different metals and alloys with different physical and mechanical properties into a single product. For example, by soldering, you can join low-carbon and high-carbon steels, cast iron parts with steel, hard alloy with steel, etc. Of particular note is the possibility of joining parts made of aluminum and its alloys by soldering. The method of soldering hard alloy plates to holders is widely used in the manufacture of cutting tools.

In a home workshop, soldering is the most accessible form of the formation of fixed, one-piece joints. During soldering, a molten filler metal, called solder, is introduced into the gap between the heated parts. Solder, which has a lower melting point than the metals to be joined, wetting the surface of the parts, connects them when cooled and solidified. In the process of soldering, the base metal and solder, mutually dissolving in each other, provide a high strength of the connection, the same (with high-quality soldering) as the strength of the entire section of the main part.

The process of soldering differs from welding in that the edges of the parts to be joined are not melted, but only heated to the melting temperature of the solder.

To make solder joints, you need: an electric or indirectly heated soldering iron, a blowtorch, solder, flux.

The power of an electric soldering iron depends on the size of the parts to be joined, on the material from which they are made. So, for soldering copper products of small sizes (for example, a wire with a cross section of several square millimeters), a power of 50–100 W is sufficient; when soldering electronic devices, the power of an electric soldering iron should be no more than 40 W, and the supply voltage should not exceed 40 V; large parts require a power of several hundred watts.

The blowtorch is used to heat the indirectly heated soldering iron and to heat the parts to be soldered (with a large soldering area). Instead of a blowtorch, you can use a gas burner - it is more productive and reliable in operation.

The most commonly used solder alloys are tin-lead alloys with a melting point of 180–280 °C. If bismuth, gallium, cadmium are added to such solders, then low-melting solders with a melting point of 70–150 ° C are obtained. These solders are relevant for soldering semiconductor devices. In cermet soldering, a powder mixture is used as a solder, consisting of a refractory base (filler) and low-melting components, which provide wetting of the filler particles and the surfaces to be joined. On sale there are also alloys in the form of bars or wire, which are a symbiosis of solder and flux.

The use of fluxes in the soldering process is based on their ability to prevent the formation of an oxide film on the surfaces of parts when heated. They also reduce the surface tension of the solder. Fluxes must meet the following requirements: maintaining a stable chemical composition and activity in the solder melting temperature range (that is, the flux under the action of these temperatures should not decompose into components), the absence of chemical interaction with the soldered metal and solder, the ease of removal of the products of interaction between the flux and the oxide film ( washing or evaporation), high fluidity. Soldering various metals is characterized by the use of a specific flux: when soldering parts made of brass, silver, copper and iron, zinc chloride is used as a flux; lead and tin require stearic acid; sulfuric acid is suitable for zinc. But there are also so-called universal solders: rosin and soldering acid.

Parts that are supposed to be connected by soldering should be properly prepared: cleaned of dirt, removed with a file or sandpaper the oxide film formed on the metal under the influence of air, pickled with acid (steel - hydrochloric, copper and its alloys - sulfuric, alloys with a large nickel content - nitrogen), degrease with a swab dipped in gasoline, and only after that proceed directly to the soldering process.

You need to heat up the soldering iron. Heating is checked by immersing the tip of the soldering iron in ammonia (solid): if the ammonia hisses and blue smoke comes from it, then the heating of the soldering iron is sufficient; Under no circumstances should the soldering iron be overheated. If necessary, its nose should be cleaned with a file from the scale formed during the heating process, immerse the working part of the soldering iron into the flux, and then into the solder so that droplets of molten solder remain on the tip of the soldering iron, heat the surfaces of the parts with a soldering iron and tin them (that is, cover them with a thin layer molten solder). After the parts have cooled down a bit, tightly connect them together; warm up the soldering place again with a soldering iron and fill the gap between the edges of the parts with molten solder.

If it is necessary to connect large surfaces by soldering, then they act somewhat differently: after heating and tinning the place of soldering, the gap between the surfaces of the parts is filled with pieces of cold solder and at the same time the parts are heated and the solder is melted. In this case, it is recommended to periodically process the tip of the soldering iron and the place of soldering with flux.

The fact that it is unacceptable to overheat the soldering iron has already been said, but why? The fact is that an overheated soldering iron does not hold droplets of molten solder well, but this is not the main thing. At very high temperatures, the solder may oxidize and the joint will be fragile. And when soldering semiconductor devices, overheating of the soldering iron can lead to their electrical breakdown, and the devices will fail (which is why soft solders are used when soldering electronic devices and the effect of a heated soldering iron on the soldering point is limited to 3–5 seconds).

When the soldering site has completely cooled down, it is cleaned of flux residues. If the seam turned out to be convex, then it can be leveled (for example, with a file).

The quality of the soldering is checked: by external inspection - in order to detect unsoldered places, by bending at the place of the soldering - no cracks are allowed (strength test); brazed vessels are checked for tightness by filling with water - there should be no leakage.

There are soldering methods that use hard solder - copper-zinc plates 0.5-0.7 mm thick, or rods with a diameter of 1-1.2 mm, or a mixture of sawdust of copper-zinc solder with borax in a ratio of 1: 2. Soldering iron not used in this case.

The first two methods are based on the use of plate or rod solder. Preparing parts for hard soldering is similar to preparing parts for soft soldering.

Next, pieces of solder are superimposed on the place of soldering and the parts to be soldered together with solder are twisted with a thin knitting steel or nichrome wire (0.5–0.6 mm in diameter). The place of soldering is sprinkled with borax and heated until it melts. If the solder has not melted, then the place of soldering is sprinkled with brown a second time (without removing the first portion) and heated until the solder melts, which fills the gap between the soldered parts.

In the second method, the place of soldering is heated red-hot (without pieces of solder), sprinkled with borax and a solder bar is brought to it (continuing heating): the solder melts and fills the gap between the parts.

Another soldering method is based on the use of a powder mixture as a solder: the prepared parts are heated red-hot at the place of soldering (without solder), sprinkled with a mixture of borax and solder sawdust and continue to heat until the mixture melts.

After soldering by any of the three proposed methods, the soldered parts are cooled and the place of soldering is cleaned from the remnants of borax, solder and binding wire. The soldering quality is checked visually: to detect unsoldered places and strength, the soldered parts are lightly tapped on a massive object - with poor-quality soldering, a kink is formed in the seam.

Varieties of solder joints are shown in fig. 53.

Rice. 53. Designs of soldered joints: a - overlap; b - with two overlaps; in - end-to-end; g - oblique seam; d - end-to-end with two overlaps; e - in Taurus.

In most cases, the parts are first tinned, which makes subsequent soldering easier. The scheme of the tinning process is shown in fig. 54.

Rice. 54. Scheme of tinning with a soldering iron: 1 - soldering iron; 2 - base metal; 3 - zone of fusion of solder with the base metal; 4 - flux; 5 - surface layer of flux; 6 - dissolved oxide; 7 - flux pairs; 8 - solder.

However, tinning can be used not only as one of the stages of soldering, but also as an independent operation, when the entire surface of a metal product is covered with a thin layer of tin to give it decorative and additional performance qualities.

In this case, the covering material is not called solder, but semi-solder. Most often they are tinned with tin, but in order to save money, lead can be added to the half-day (no more than three parts of lead to five parts of tin). The addition of 5% bismuth or nickel to the tin gives the tinned surfaces a beautiful sheen. And the introduction of the same amount of iron into the half-day makes it more durable.

Kitchen utensils (dishes) can only be tinned with pure tin half, the addition of various metals to it is dangerous to health!

The half-day lies well and firmly only on perfectly clean and fat-free surfaces, therefore, before tinning, the product must be thoroughly cleaned mechanically (with a file, scraper, sandpaper to a uniform metallic sheen) or chemically - hold the product in a boiling 10% caustic soda solution for 1–2 minutes, and then etch the surface with a 25% hydrochloric acid solution. At the end of cleaning (regardless of the method), the surfaces are washed with water and dried.

The tinning process itself can be carried out by rubbing, dipping or galvanizing (such tinning requires the use of special equipment, so galvanic tinning at home, as a rule, is not carried out).

The rubbing method is as follows: the prepared surface is covered with a solution of zinc chloride, sprinkled with ammonia powder and heated to the melting point of tin.

Then you should attach a tin rod to the surface of the product, distribute the tin over the surface and grind it with clean tow until a uniform layer is formed. Re-lubricate untinned places. Work should be done in canvas gloves.

In the dip tinning method, tin is melted in a crucible, the prepared part is grasped with tongs or pliers, immersed for 1 minute in a solution of zinc chloride, and then for 3-5 minutes in molten tin. The part is removed from the tin and the excess of the tin is removed by strong shaking. After tinning, the product should be cooled and rinsed with water.

Welding

To create fixed, permanent joints, welding is also widely used, through which an interatomic bond is established between the parts to be joined.

Depending on the form of energy used in the formation of a welded joint, all types of welding are divided into three classes: thermal, thermomechanical and mechanical (Table 1).

Table 1. Classification of types of welding

Of course, not all types of welding can be done in a home workshop. Most of them require sophisticated equipment. Therefore, we will consider in more detail those types of welding that are most accessible to the home master.

But first, about the preparation of parts that are intended to be joined by welding: oily places must be washed with a solution of caustic soda, and then with warm water, the welding points should be treated with a file and an organic solvent, the edges should be sawed off or milled to form a chamfer.

Most often, gas welding is used in domestic conditions (Fig. 55, a). The principle of gas welding is as follows: gas (acetylene), burning in the atmosphere, forms a flame beam that melts the filler material - wire or rod. The molten rod fills the gap between the edges of the parts, resulting in a weld. Gas welding can weld both metals and plastics.

Rice. 55. Types of welding: a - gas: 1 - filler material; 2 - welding torch; b - consumable electrode arc welding: 1 - consumable electrode; 2 – electrode holder; c - electric arc welding with a non-consumable electrode: 1 - electrode holder; 2 - non-consumable electrode, 3 - filler material; d - scheme of explosion welding: 1, 2 - welded plates; 3 - explosive charge; 4 - electric detonator.

Electric arc welding is also widespread (Fig. 55 b, c). It can be produced both with a consumable electrode and non-consumable - coal or tungsten (in this case, filler material is additionally introduced into the zone of the melting arc).

Medium-, high-carbon and alloy steels belong to the category of metals with limited weldability. To avoid cracks when welding parts made of these materials, they are preheated to a temperature of 250–300 °C. Details from sheet steel up to 3 mm thick can be welded by gas welding.

The scheme of explosion welding is shown in fig. 55, d: one of the plates to be welded is fixedly mounted on the base, a second plate is placed above it at a height h, on which an explosive charge is placed. The electric detonator explodes the charge, as a result of which the detonation wave, which has a high speed and high pressure, informs the second plate of the impact speed. At the moment of contact of the plates, they are welded.

It is difficult to carry out other types of welding at home (devices for diffusion, laser, electron beam and other types of welding are not as widely available as welding machines for arc or gas).

Assembly of rivet joints

If the assembly unit (joint assembly) during operation will be subjected to large dynamic loads and the soldering method is not applicable due to the fact that the parts are made of metals with poor weldability, then in these cases riveted joints are used.

The rivet is a metal rod of circular cross section, with a head at the end, which is called a mortgage and is semicircular, secret and semi-secret in shape (Fig. 56).

Rice. 56. Types of rivets: a - with a countersunk head; b - with a semicircular head; in - with a flat head; g - with a semi-secret head; e - explosive rivet: 1 - recess filled with explosive.

Rivets are drilled with a drill having a diameter larger than the diameter of the rivet shaft. The dimensions of the rivets depend on the thickness of the parts to be riveted.

The riveting operation itself is preceded by the preparation of parts for the implementation of this type of connection. First you need to mark the rivet seam: if the riveting will overlap, then the upper part is marked, for butt riveting, the overlay is marked.

In this case, it is necessary to observe the step between the rivets and the distance from the center of the rivet to the edge of the part. So, for a single-row riveting t = 3d, a = 1.5d, for a double-row riveting t = 4d, a = 1.5d, where t is the pitch between the rivets, a is the distance from the center of the rivet to the edge of the part, d is the diameter of the rivet.

Next, drill and countersink holes for the rivet rods. When choosing the diameter of the drill, it should be noted that for rivets with a diameter of up to 6 mm, a gap of 0.2 mm must be left, with a rivet diameter of 6 to 10 mm, the gap should be 0.25 mm, from 10 to 18 mm - 0.3 mm. When drilling holes, it is necessary to strictly observe the angle between the axis of the hole and the planes of the parts at 90 °.

In the direct method, blows are applied from the side of the closing head, and for good contact of the riveted parts, their tight compression is necessary. With the reverse method, blows are applied from the side of the insert head, and a tight connection of the parts is achieved simultaneously with the formation of the closing head.

Riveting is carried out in the following sequence (Fig. 57):

- select rivet rods with a diameter depending on the thickness of the sheets to be riveted:

where d is the required diameter, s is the thickness of the sheets to be riveted. The length of the rivets should be equal to the total thickness of the parts to be riveted plus the allowance for the formation of the closing head (for countersunk - 0.8–1.2 rivet diameter, for semicircular - 1.25–1.5);

- rivets are inserted into the extreme holes of the riveting seam and the embedded heads are supported on a flat support, if the heads should be countersunk, or on a spherical one, if the heads should be semicircular;

- upset the parts at the place of riveting until they fit snugly;

- upset the rod of one of the extreme rivets with a hammer striker and flatten it with the hammer nose;

- further, if the head should be flat, then the hammer striker aligns it, if it is semicircular, then the side impacts of the hammer give it a semicircular shape and, using a spherical crimp, achieve the final shape of the closing head;

- in the same way, the second extreme rivet is riveted, and then all the rest.

Rice. 57. The sequence of the manual forging process: a - rivets with countersunk heads.

Rice. 57 (continued). The sequence of the manual riveting process: b - rivets with semicircular heads.

The connection of parts (mostly thin) in hard-to-reach places is carried out with explosive rivets with an explosive in the recess (Fig. 56, e). To form a joint, the rivet is put in place in a cold state, and then the embedding head is heated by a special electric heater for 1-3 seconds to 130 ° C, which leads to an explosion of the explosive filling the rivet. In this case, the closing head acquires a barrel-shaped shape, and its expanded part tightly tightens the sheets to be riveted. This method is characterized by high productivity and good riveting quality.

It is necessary to introduce explosive rivets into the holes by smooth pressing, without impacts. It is forbidden to remove varnish, discharge rivets, bring them to fire or hot parts.

When riveting by hand, a bench hammer with a square head is often used. The mass of the hammer to ensure a quality connection must correspond to the diameter of the rivets. For example, with a rivet diameter of 3–4 mm, the weight of the hammer should be 200–400 g, and with a diameter of 10 mm, 1 kg.

If the drill diameter for making a hole for rivets, the diameter and length of the rivet itself are incorrectly selected, if other operating conditions are violated, rivet joints may have errors (Table 2).

Table 2. Marriage in rivet joints and its causes

If a marriage is found in rivet joints, incorrectly set rivets are cut or drilled and riveted again.

Pneumatic riveting hammers with a spool air distributor greatly facilitate riveting. With a small consumption of compressed air, they are characterized by high performance.

Gluing

Bonding of parts is the last type of assembly of fixed, one-piece joints, in which a layer of a special substance is introduced between the surfaces of the parts of the assembly assembly, capable of holding them motionless - glue.

This type of connection has a number of advantages: firstly, the possibility of obtaining assembly units from dissimilar metals and non-metallic materials; secondly, the gluing process does not require elevated temperatures (as, for example, welding or soldering), therefore, deformation of parts is excluded; thirdly, the internal stress of materials is eliminated.

In fitting and assembly work, adhesives are usually used: EDP, BF-2, 88N (Table 3).

Table 3. Grade of glue and its scope

Like all other types of joints, the quality of glued joints largely depends on the correct preparation of the surfaces for the gluing process: they should not be stained with dirt, rust, traces of grease or oil. Surfaces are cleaned with metal brushes, sandpapers, the material for removing grease and oil stains depends on the brand of glue used: gasoline is used when gluing parts with 88N glue, acetone is used for EDP and BF-2 glues.

The process of gluing parts consists of the following operations:

- prepare the surfaces of the parts and select the brand of glue (see above);

- apply the first layer of glue on the surfaces at the joints (this operation can be performed with a brush or watering), dry, apply a second layer of glue, connect the parts and press them together with clamps (here it is important to monitor the exact match of the parts and their tight fit);

– withstand the glued knot and clean the seams from glue smudges.

Drying mode of the first adhesive layer: EAF is applied in one layer and does not require drying; BF-2 requires drying for 1 hour at a temperature of 20 ° C (“tack-free”); 88N - 10-15 minutes in air. After applying the second layer, hold for 3-4 minutes and only then connect the parts.

Holding mode for glued joints: when using EDP glue - 2–3 days at a temperature of 20 °C or 1 day at a temperature of 40 °C; glue BF-2 - 3–4 days at a temperature of 16–20 °C or 1 hour at a temperature of 140–160 °C; glue 88N - 24-48 hours at a temperature of 16-20 ° C under load.

When assembling machines and mechanisms, sometimes combined glued joints are used - glue-welded: a layer of VK-9 glue is applied to the mating surface of one of the parts, and the second part is welded by spot welding on this layer.

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Fundamentals of locksmith and assembly work technology

Basic concepts about the assembly and its elements

Assembly is the final step in the manufacturing process.

assembly process, as a rule, consists of such successive stages as:

manual locksmith processing and preparation of individual parts for assembly (deburring, chamfering, etc.), is used mainly in single and small-scale production and in small volumes - in serial production;
nodal assembly - connection of parts into sets, subassemblies, units (mechanisms);
general assembly - assembly of the entire machine;
regulation - installation and reconciliation of the correct interaction of parts and testing of the machine.

Technological assembly process- this is the connection of parts into assembly units, and assembly units and individual parts - into mechanisms (assemblies) and machines. The assembly process is divided into operations, installations, positions, transitions and techniques.

Operation- the main part of the assembly process, performed on a specific product, group, assembly, subassembly or set at one workplace by an assembly fitter or team.

Installation- part of the assembly operation, performed with a constant position of the assembled kit, assembly, group or product (machine).

Position- each of the various positions of the assembled kit, subassembly or assembly (both in the assembly fixture and without it).

Transition- this is a completed part of the technological operation, characterized by the constancy of the tool used and the surfaces formed by processing or connected during assembly.

Reception- this is part of a technological transition, consisting of a series of simple working movements performed by one worker (for example, clamp a part in a vice or take a wrench, etc.).

The number of products produced is determined by the type of production and the degree of dismemberment of the assembly process into separate operations.

All products consist of assembly units.

Product- this is any item or set of items of the main production, manufactured at the enterprise. The products of machine-building plants are a variety of machines: machine tools, automobiles, tractors, excavators, presses, etc., as well as individual mechanisms and machine assemblies (engines, pumps, carburetors, etc.) or individual parts (piston rings, pistons, hardware).

Detail- this is the primary element of the product, made of a homogeneous material without the use of assembly operations, but with the use, if necessary, of protective or decorative coatings.

Set is a connection of two or more machine parts into the simplest assembly unit (for example, a shaft with a fitted key, a gear wheel with a locking screw, a cover with a ball bearing).

subnode- connection of several parts with one or more sets (for example, the shaft of the gearbox of a lathe with gears mounted on it, bushings, bearings, etc.).

Assembly unit (node)- this is an element of the product, consisting of two or more components (parts or sets and subassemblies), interconnected by assembly operations (screwing, gluing, welding, soldering, riveting, flaring, etc.) at the manufacturer (for example, a coupling, caliper, gearbox, etc.).

Units during assembly are assembled into assembly groups.

group is called a node or connection between nodes and parts that are directly part of the machine or machine. A node included directly in a group is called a subgroup of the first order; a node that enters directly into a subgroup of the first order is called a subgroup of the second order, and so on.

When drawing up an assembly unit diagram, the concepts of “base part” and “base assembly unit” are used.

base part name the main part from which the assembly of the assembly unit begins, and basic assembly unit- the main assembly unit from which the assembly of the product begins.

The mutual connection of parts during the assembly of machines and mechanisms is determined by the degrees of freedom of their relative movement. Accordingly, all connections used in the assembly are divided into fixed and movable.

Mobile connections used to achieve a certain type of movement of one part relative to another.

Fixed connections used to hold parts in the desired permanent position.

Movable and fixed joints are divided into detachable (disassembled) and one-piece (non-disassembled).

Detachable such connections are called that are disassembled without damage to the connected and connecting parts. This includes all types of threaded connections, connections with pins, wedges, keyways, splines and other connections that can be called profile.

The parts to be connected include machine parts of various purposes and designs. Standard parts: rivets, dowels, bolts, screws, studs, nuts, washers - belong to connecting, or so-called fasteners.

Detachable connections are used for repeated disassembly and assembly during operation and repair.

Movable connectors- connections using movable landings on cylindrical, conical, spherical, helical and flat surfaces in various ways, for example, connecting crankshaft journals with main bearings and the lower head of the connecting rod.

TO fixed connectors include threaded, keyed, splined, wedge and pin connections.

One-piece connections are called, the disassembly of which under the conditions of operation and repair of machines is possible only with damage to the connected and connecting parts. As a result, damaged parts are unsuitable for reassembly.

Permanent connections are usually used when the division of the structure into its component parts is not caused by the convenience or economy of manufacture, as well as by the requirements of operation.

Movable one-piece connections - these are separate types of movable joints assembled using riveting or flaring. For example, to disassemble a ball bearing, it is necessary to cut the cage rivets.

TO fixed permanent connections include joints made by pressing or expanding, as well as riveted, welded, obtained by soldering, gluing, bending edges, etc.

Before developing the assembly process, they get acquainted in detail with the design of the machine, the interaction of its parts, the technical conditions for the manufacture, acceptance and testing of the machine.

Forms of organization and assembly methods

Depending on the type of production, the complexity of assembly work and other factors, the forms of organization of assembly work may be different. There are two main forms of assembly - stationary and mobile.

Stationary Assembly can be done in two ways:

without dismembering the assembly process into parts;
with the dismemberment of the assembly process into a nodal and general assembly. At stationary assembly without dismembering the assembly process into parts the entire assembly process (starting with the receipt of parts and ending with the testing of the assembled machine) is carried out at one workplace by one team.

With this method of assembly, the qualifications of fitters must be high, since everyone has to perform a variety of work. The disadvantages of this assembly method are the long duration of the process and the need for additional space to accommodate all the parts and carry out preparatory assembly work, so it is used mainly in single-piece production.

At stationary assembly with dismemberment the process of assembling a machine is divided into nodal and general assembly. At the nodal assembly, several workers or a team simultaneously assemble the nodes, which are then fed to the general assembly, where the entire machine is assembled by a separate team. This method makes it possible to simultaneously assemble several separate units or machines, as a result of which the assembly time is significantly reduced. With this method, fitters specialize in assembling individual units, as a result, labor productivity increases and the quality of manufactured products improves.

The main maintenance and current repairs of the car are cleaning and washing, disassembly, assembly, fastening, adjustment and lubrication and cleaning, called plumbing and assembly. Every worker involved in the maintenance and repair of a car, every driver must have the skills of metalwork and assembly work.

Mastering them is one of the main tasks of the student's industrial practice.

"Workshop on the car", V.P. Bespalko, M.I. Eretsky, Z.V. Rosen

A necessary condition for the quality performance of maintenance and current repairs of the car is cleanliness. If they work at a post without disassembling into units, the entire car, or at least the part that is being repaired or adjusted, should be thoroughly washed, and when working from below, also dried: the water should drain before starting work. The unit removed from the car is accepted for repair ...

You can work under the car only after a sign is hung on the steering wheel with the inscription: “Do not start the engine - people are working!” You need to make sure that fuel, oil, electrolyte are not leaking. Do not place the tool and parts on the frame, footboards and other parts of the car - if they fall, they can injure. If you have to work under the car lying down, apply ...

The durability and gloss of the paintwork of the body is achieved by polishing materials. Remove washable stains with No. 1 Polishing Water. No. 2 Wax Paste and No. 3 Liquid Wax Compound restore shine and protect the finish from dust and moisture. Polishing pastes No. 290 and No. 6/7, containing abrasive components, are used for loss of gloss for ...

Work on the body of a bus or a high truck, as well as on the side or on top of a car on a lift, must be carried out using only ladders with a step width of at least 15 cm. You can work on tilters after removing the battery, draining the fuel from tanks and water from the cooling system, filler seals and crankcase oil dipstick holes…

The main operations when disassembling a car and its units are unscrewing threaded connections and disconnecting mating parts. Keys are the main disassembly and assembly tool. They are distinguished by size in mm - 6, 7, 8, 9, 10, 11, 12, 14, 17, 19, 22, 24, etc. and by type - open, ring, socket wrenches and socket heads with ...

During the operation of engines, the evaporation of gasoline and detergents, welding and copper work, charging batteries and others, harmful impurities are formed. The removal of polluted air and the supply of fresh air are provided by natural and artificial ventilation. The first is carried out by opening the vents, transoms and windows. The second - with the help of fans driven by electric motors. In addition, local suctions are used. Local sucks Local sucks:…

To separate parts assembled on splines or keys, as well as press connections, sometimes very large forces are required. Significant forces can be created with pullers, table and stationary presses. You can also separate parts with blows. In order not to damage the parts, use copper, brass or aluminum alloy punches or hammers. Pullers for Pullers for: a - pulley;…

Industrial clothing (overalls) for drivers and mechanics - moleskin overalls. Technicians working on leaded petrol vehicles are provided with dungarees and a moleskin jacket with patches made from a special oil-resistant material. The electric welder must be dressed in tarpaulin trousers and a jacket, leather boots and mittens. Washers put on a suit made of rubberized or waterproof fabric. Fire safety at motor transport enterprises is ensured by…

The locksmith should occupy a comfortable, stable position. So, when servicing and repairing an engine installed on a car, a special stand mounted on the front wheel is convenient. Stand for a locksmith Stand for a locksmith servicing or repairing the engine or electrical equipment of a ZIL-130 car. Removing the gearbox with the help Removing the gearbox with the help of: a - a winch-type device; b - trolleys with ...

High labor productivity and high-quality performance of assembly, fastening and adjustment work is achieved by observing the conditions outlined below. Cleanliness of parts Dirt, dust, metal chips are the causes of accelerated wear of working parts. Parts in good condition Each part is checked before assembly to ensure that it meets the repair and assembly specifications issued for each vehicle model. The serviceability of threaded connections is established by inspection: on ...

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7 Locksmith processing, assembly and installation works

The totality of the actions of all departments of the enterprise for the repair of the vessel is called the production process. The production process covers not only all stages of the repair and installation of ship mechanisms and the ship's hull, but also the technical preparation of production necessary for this, maintenance of workplaces, receipt and storage of materials, semi-finished products, parts, assemblies and their transportation, management of all stages of production, provision of tools , equipment repair, etc.

Part of the production process directly related to the sequential change in the properties of materials and the shape of manufactured parts or to the assembly of mechanisms, devices and their installation on a ship is called the technological process.

In accordance with this, the following types of technological processes are distinguished:

Machining is the process by which a workpiece is transformed into a finished product.

part of given qualities and dimensions by successive chip removal,

heat treatment, plastic deformation (forging, stamping) and others

ways;

Assembly is a process in which individual parts are connected in series between

itself into nodes, and nodes and parts - into ready-made mechanisms and devices capable of

perform their assigned functions;

A node is an assembly unit, which is understood as a product obtained by

assembly of individual parts.

Installation is a process in which various mechanisms, devices and elements of systems are loaded onto a ship, and then installed and fixed in a given position at the place of their future work.

The technological process is carried out at one or more workplaces.

The workplace is understood as a certain area in the workshop or on the ship, which has the appropriate technological and auxiliary equipment, fixtures and fittings (machine, locksmith's workbench, scaffolding on the ship, etc.) necessary to perform the specified work.

An operation is a completed part of the technological process, performed at one specific workplace and covering the operation of equipment and all the actions of a worker or a team of workers on one or more specific items of production. During assembly and assembly operations, the objects of production are: simultaneously assembled parts and assemblies, ready-made mechanisms and means for regulating their position and fixing. Operations, in turn, are divided into transitions.

A transition is a part of operations performed without changing the tool, cutting mode and without rearranging the workpiece (on the machine, in a vice, in a fixture). If the worker changes the tool or begins to process another surface of the same part, then he will thereby begin to perform another transition.

In some cases, especially in manual or semi-mechanical processing or assembly of parts, operations are divided into techniques.

A reception is a set of actions of a worker that have a specific purpose and constitute a complete element of the operation. When performing metalwork and assembly work, acceptance is understood as the completed action of the worker from among those necessary to complete the assembly operation or its preparation. For example, such a technique as scraping the bushing of a plain bearing, in some cases, is performed during the operation - installing the bushing in the bearing housing.

The main technological documentation when performing metalwork and assembly work is an assembly drawing, a technological map and an assembly process.

The technological process is developed in the technological department of the enterprise. The development of the technological process begins with drawing up a diagram of the assembly elements. Then they begin to develop the main technological document of the assembly - the technological map. In the technological map, in a certain sequence, indicate the operations performed during assembly, the tools and fixtures necessary for this, as well as the corresponding assembly and detail drawings. The totality of a number of technological maps constitutes the assembly process.

The duty of the worker who is entrusted with the assembly of any mechanism is a thorough study of the technological process, assembly and detail drawings, the preparation of the necessary tools and fixtures.

When assembling mechanisms in a workshop, a locksmith needs to know and be able to perform many locksmith and fitter-assembly operations: filing, scraping, hardening, tinning, pouring bearings, riveting and chasing, assembling various joints.

There are two main types of assembly joints: fixed and movable. If, according to the operating conditions of a machine or mechanism, it is necessary to ensure a constant relative position of one part relative to another (or one node relative to another), then such a connection of parts is called fixed.

Depending on the design of the machine and its operating conditions, fixed connections can be detachable and non-detachable.

Fixed detachable connections are such assembly connections that can be disassembled without damaging mating and fasteners. Such connections include threaded connections (bolted, stud, screw) and smooth non-threaded connections (pin, key, spline).

Fixed one-piece connections are assembly connections that cannot be disassembled without damaging any part included in the connection. Such connections can be made by welding, soldering, riveting, pressing, as well as by gluing, molding with plastics or by vulcanizing.

studfiles.net

Fitting and assembly work - Chemist's Handbook 21

GOST 11516-79 Fitting and assembly tool for work in electrical installations with voltage up to 1000 V. Insulating handles. General specifications.

Description of the equipment and general instructions for its installation Technical characteristics of the equipment to be installed List of necessary measuring and assembly tools, rigging equipment and auxiliary materials Instructions for locating the equipment at the storage site and in the engine room water installation schedule.

Fitting and installation work on heating furnaces - assembly and installation of furnace frames installation of brackets for bricks, hangers, supports and installation of assembled coils, and in some cases tube sheets assembly of coils from pipes and twins rolling of pipes in twins hydraulic testing of furnace coils, etc.

During the installation of heating networks, the following types of work are carried out: transport and rigging, welding, fitting and installation and thermal insulation.

By the beginning of the installation work, the work of the zero cycle preparation of access roads and driveways, the manufacture of foundations, the covering of installation sites with prefabricated reinforced concrete slabs, the provision of sites with water supply, electricity, and sewerage should be completed. The organization of the site includes the installation of brigade and foreman's houses, the equipment of tool storage and repair shops with emery and drilling machines and metalwork benches, the equipment of a pre-assembly site and equipment storage areas.

Pneumatic files are designed for mechanization of the filing process during plumbing and assembly work.

The production base of the assembly organization should have boiler-welding, metalwork-mechanical, blacksmith, pipe-procurement, as well as central tool facilities. The capacity of the production base is determined by calculation. The calculation is based on the maximum annual volume of installation work on the construction site, as well as the degree of industrialization of installation work. The scope of work of the production base of the installation organization is expressed as a percentage of the volume of installation work. The data for such a calculation are given in Table. 1-3.

In addition, a characteristic feature of this structure is the presence of units for the complex repair of certain types of removable equipment that carry out in-line production of work. For this purpose, specialized workshops are supplied with all the necessary equipment - both machine tools and metalwork and assembly - which is installed on the operational route sections. This group of subdivisions is headed by one leader, who, like the head of both groups of installation subdivisions, reports to the head of the centralized repair service.

In addition, the engine room includes a boiler room designed for heating various service rooms and heating in winter for storage of goods with positive temperatures. personnel of the engine room of the room foreman or mechanic.

Prior to the start of installation work, the serviceability of lifting mechanisms, tools and fixtures should be checked, good lighting of the installation site, workplaces and strong fencing of hatches, pits and trenches should be provided. Workers must be provided with the necessary overalls and serviceable protective equipment (gas masks, gloves, rubber gloves, goggles, etc.). Installers performing rigging, metalwork, welding and other work must be instructed in safety. The briefing is recorded in a special journal.

Fitting and assembly devices. In the production of installation work, a variety of universal and special devices are used, as well as assembly stands and conductors, which facilitate the performance of a particular operation. For example, when pairing the edges, rack-mount screw ties and wedge ties are used when straightening cylinders - radial ties and spacers, as well as lever-screw ties and clamps of various designs and configurations when straightening pipe ends - hydraulic expanders for centering

The growth in the volume of work, the increase in the technical complexity of oil and chemical enterprises under construction, associated with an increase in the overall dimensions and weight of equipment, an increase in pressure, temperature and other technological parameters, put forward new requirements for the quality of training of workers for installation organizations. A modern worker engaged in the installation of technological equipment must know not only the methods of performing rigging and fitting and assembly work, but also be well versed in the device and purpose of the equipment being installed, know the technical requirements for its installation, testing and start-up. All these issues are addressed in this textbook.

Safety rules for assembly, metalwork and assembly, rigging and welding work, as well as for the commissioning and start-up of refrigeration units, have been developed and approved.

SSBT, Fitting and assembly work during the repair of ships.

DGSD are recruited on a voluntary basis from workers and engineers of gas and explosive workshops of the enterprise, who are well aware of the production process, technical equipment and fitter and installation work.

Voluntary gas rescue squads (VGSD) are organized to provide assistance to gas rescue service units, as well as for independent work to save people, eliminate accidents and perform gas hazardous work at enterprises that do not have a gas rescue service. Such squads are formed on a voluntary basis from workers and engineering and technical workers of explosive shops and installations who are well acquainted with production technology, technical equipment and have the skills of plumbing and assembly work. The members of the voluntary gas rescue squad are distributed in such a way that there are approximately the same number of them in each shift and the practical possibility of emergency and rescue work is provided. All employees of the squad must be able to use rescue equipment, carry out repair and restoration work, and provide first aid to the victims.

Marking tools. When performing marking work, control and measuring rulers, levels, plumb lines, levels (locksmith, assembly-frame and hydrostatic), as well as steel sharpened scribers are used.

Each installation organization distributes the entire scope of work to be performed among its production units, some of which are located on the territory of the facility under construction. Production units perform rigging work (loading, unloading, moving and installing equipment in the design position), fitter and installation work (assembly of equipment, mainly technological devices), mechanical installation work (installation and adjustment of pumps, compressors, centrifuges, fans, mills etc.), installation of metal structures (assembly of stairs, platforms, load-bearing frames, etc.), welding, piping and some other works.

The basis for increasing labor productivity and quality, as well as improving the working conditions of repair personnel, is the mechanization of heavy, labor-intensive, harmful and dangerous work. The locomotive is dismantled at a dismantling or repair position with dismantling and moving heavy and bulky assembly units. To increase the level of mechanization of dismantling operations, positions are equipped with mechanized metalwork and assembly tools in the form of pneumatic wrenches of various types. To perform typical handling and special operations, depending on the type of repair being performed, workshops are equipped with different mechanisms. In the TO-3 maintenance and repair shop TR-1, five- or ten-ton cranes are installed for removing assembly units, a ski lift for single rolling out and changing the wheel-motor unit, a wheel-turning machine of the KZh-20 type for turning bandages without rolling out wheel sets .

To assist the units of the gas rescue service, as well as for independent work, at enterprises that do not have gas rescue units, voluntary gas rescue teams (DGSD) are organized, which are staffed from among workers and engineering and technical workers who know the technological process well and are familiar with the fitter and assembly deed. They are not released from their basic work, but if necessary, perform emergency and rescue work. The members of the team are distributed so that in each shift there are approximately the same number and the practical possibility of emergency and rescue work is provided. All members of the team are instructed, trained and trained.

Fitting and installation work on apparatuses - pre-assembly of individual finished blocks and units of apparatuses installation of distillation plates in columns closing of hatches in apparatuses assembly and installation of coils of submersible condenser-coolers installation of coils, cyclones, bar-boats and other devices inside apparatuses hydraulic and pneumatic testing of apparatuses reconciliation of the installation of devices, fixing them on the foundations, etc.

Fitting and installation work. The reliability of the installed networks depends on the performance of plumbing and installation work, so they are subject to high requirements. When laying and installing heating networks, the following requirements are observed; the slopes of the pipelines to be laid are made in accordance with the project, and if the project does not have drawings, then the slope should

When installing pipelines, fitting and installation tools are used, both for general purposes (wrenches, hammers, chisels, edge grinders, screwdrivers, etc.), and special ones, designed to facilitate and speed up installation work.

Production and installation sites are usually located on the territory of the facility under construction. They perform rigging (loading, unloading, moving and installing equipment in the design position), fitter and assembly (assembly of equipment, mainly technological devices), mechanical assembly (assembly and adjustment of pumps, compressors, centrifuges, fans, mills, etc. .) works, installation of metal structures (assembly of stairs, platforms, load-bearing frames, etc.), welding, piping and some other works.

Must know elementary information about brands of cables and cable accessories, their areas of application, storage rules and methods for rolling cables from drums, locksmith, measuring and special tools for cable work, the appointment of mounting devices and structures, general information about cable and scalding masses, solders and fluxes, materials, rules for loading and transporting cables and cable drums, rules for earthworks used in the repair of cable lines.

To protect personnel working in electrical installations from electric shock and the effects of an electric arc, various protective equipment is used: insulating rods (operational, measuring, for grounding), insulating and electrical clamps, voltage indicators, voltage indicators for phrasing, insulating means for repair work under voltage above 1000 V and fitting and assembly tools with insulating handles dielectric gloves, boots, galoshes, rugs, insulating stands portable grounding temporary fences warning posters goggles, mittens, gas masks, safety fitters' belts, safety helmets. By-. the order of using protective equipment, the norms and terms of electrical and mechanical tests are established based on the PTE.

To mechanize the process of cutting internal and external threads during fitting and assembly and installation work, various portable electric and pneumatic manual machines - threaders are successfully used. They differ from drilling machines in the presence of a device for mechanically reversing the rotation of the spindle.

The characteristic features of this structure is the presence of a group of departments for the complex repair of certain types of volumetric equipment, carrying out in-line production of work. For this purpose, specialized workshops are supplied with machine tools and metalwork and assembly equipment, which are installed on operational route sections, the leader of both groups of assembly units reports to the head of the centralized repair service.

Prior to the start of technological operations, it is necessary to carry out a set of preparatory work, including studying the technological regulations, project documentation, including changes and additions made during the construction process, studying the object in kind and its connection with the off-site facilities. After completion of construction and installation works, it is necessary to check the cleanliness of the territory of the facility, as well as driveways, stairwells, approaches to fire-fighting equipment, closing of trays, wells, pits, the presence of inscriptions or plates on the premises, equipment and pipelines indicating the purpose, working conditions, environment and direction of movement. completeness of the installation with fire extinguishing equipment, gas protection, first aid kit, posters and warning labels on safety, fire and gas prevention in prominent places. The provision of the installation with the necessary lubricants, bench tools, gasket materials and rags, portable lamps, the availability and correctness of passports for equipment and equipment, the availability of Gosgortekhnadzor permits for the operation of pressure equipment, as well as acts for testing and adjusting safety valves are checked (it is necessary to make sure that the installed safety valves are adjusted in accordance with the acts).

In addition, the assembly team should have a complete set of locksmith tools (vices, hammers, sledgehammers, crowbars, files, hacksaws, wrenches of all sizes, adjustable wrenches, scrapers, screwdrivers, punches, etc.), as well as a set of tools necessary for the production of pipeline work (pipe cutters, pipe clamps, gas pliers and wrenches, screw plugs and taps for gas threads, etc.).

Technologists of the assembly site participate in the organization of the pre-assembly revision of equipment, organize the assembly site, equip it with lifting mechanisms and devices, supply it with electricity, compressed air, lighting and water, equip workplaces with locksmith and electrical assembly workbenches and stands, as well as racks for receiving and storing of pipe blanks equip workplaces with manual and lever winches, parts, cables, mechanized electric and pneumatic tools, as well as construction inventory scaffolding and scaffolding, etc. ensure the safe work of teams at workplaces in accordance with safety requirements perform fire safety measures at the installation site organize places rest and smoking, a room for eating and equip temporary and permanent sanitary facilities.

chem21.info

Execution - plumbing work - The Big Encyclopedia of Oil and Gas, article, page 3

Execution - locksmith work

Page 3

When performing plumbing work, a vice is often used. Previously, a parallel vice with a screw clamp was used for this purpose - In order to mechanize the operation of fixing parts, it is recommended to use a vice with a pneumatic drive. It takes 4 times less time to fix a part or release it from a pneumatic vice than to fix it with a screw vice. The vice consists of a body fixed on the base, fixed and movable jaws, a pneumatic cylinder and a reversing valve. The clamping force is adjusted by changing the air pressure.

When performing locksmith work, special attention should be paid to the organization of work, the condition of the tool and compliance with the rules of safe work. At the workplace of a car repairman, there must be appropriate technological equipment, fixtures and tools.

When performing locksmith work manually, it is necessary first of all to monitor the serviceability of the tool.

When performing plumbing work, it is necessary to strictly observe the dimensions of the manufactured part of the pipeline or the processing of any parts and fittings installed on the pipelines.

When performing plumbing work, the causes of bruises, wounds and burns are most often a malfunction of the working tool or an incorrect method of work.

When performing plumbing work, they use a variety of tools and fixtures. A locksmith uses one group of tools quite often. He receives this tool from the tool storeroom for permanent use. Another group of tools, fixtures and devices, used relatively rarely, may be in common use in the locksmith's area; these tools are taken by the locksmith from the pantry for the duration of his assignment.

When performing plumbing work, they usually resort only to cold riveting. Hot riveting is performed, as a rule, in specialized workshops. Cold riveting is widely used in aircraft construction.

When performing repair and installation plumbing work, in some cases they use a portable vice; they are attached to a stable workbench, which is installed near the place of work.

When performing repair and installation plumbing work, in some cases they use a portable vice; they are attached to a stable workbench, which is arranged near the place of work.

Pistol-shaped rotary drilling machines of small size are widely used in plumbing work. On fig. 176, and the RS-8 pneumatic drill used for drilling small holes (up to 8 mm in diameter) is shown.

In the manufacture of complex parts, the performance of precise locksmith work using a conventional vice is often difficult because the part must be carefully calibrated after rearrangements.

Electrician of the 3rd category: performing simple electrical and plumbing work using mechanized tools and machines.

Must know: basic techniques for performing simple plumbing work; the purpose and rules for the use of a simple locksmith instrument, the name and marking of metals, oils, fuels, lubricants, detergents.

Pages: 1 2 3 4

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Safety measures during fitting and installation work

⇐ PreviousPage 24 of 28Next ⇒

An analysis of industrial injuries during repair work showed that a significant number of injuries occur during disassembly and assembly operations. Therefore, the correct organization of the workplace and compliance with the rules for using tools, equipment and fixtures are the main conditions for the safety of a fitter.

They disassemble and assemble machines, aggregates and assembly units at specially designated sites or workplaces using small-scale mechanization and lifting and transport mechanisms.

Disconnected round or long components of machines are placed on special stands or racks. Heavy parts are placed on their lower shelves. It is not allowed to store parts in bulk near the dismantled machine or on workbenches.

Work under the raised bodies of the machines is carried out only with the installed stop bar, which prevents the lowering of the body. If the unit is dismantled on the floor, it must be installed in such a way that it cannot tip over. Engines are disassembled and assembled only on special stands that firmly hold the engine in any position.

It is forbidden:

carry out disassembly and assembly work of machines, units and assembly units held on the cables of lifting mechanisms;

blow off dust, chips and other objects with compressed air;

remove long components of machines by one worker.

The removal and installation of compression springs is considered a very dangerous operation. When doing this, you need to use

special devices equipped with protective covers, or pullers. Bushings, bearings and other parts are pressed out and pressed in using special tools and presses or hammers with copper heads. To check the alignment of the alignment of the holes, you need to use special mandrels or a beard. Do not check the alignment of the holes with your fingers. When cutting metal fixed in a vice, goggles should be worn to protect the organs of vision from flying particles. For the safety of nearby workers, workplaces are fenced off.

The use of a serviceable tool and compliance with the rules for working with it largely contribute to reducing the risk of injury during disassembly and assembly operations. The worker himself must monitor the condition of the tool.

Wrenches should only be used with the correct size. Do not use open-end wrenches with a deformed or sawn jaw, non-parallel jaws, as well as box and socket wrenches with crumpled edges or cracks in the heads. Sliding keys must not have a gap in the moving parts. It is forbidden to insert gaskets into the mouth of the key if it does not match the size of the nut or bolt head, hit the key with a hammer, increase the keys one by one using pipe segments or in another way, and also use a hammer and a chisel to loosen bolts or nuts. To facilitate loosening of rusted threaded connections, kerosene is applied to them with a brush (using goggles) and kept for 10 ... 15 minutes.

Often, to reduce labor costs in disassembly and assembly work, various pullers and installation devices are used. Pullers must be undeformed, free of cracks, stripped or bent threads. It is necessary to install the puller on the part carefully, making sure that the paws securely wrap around the removed assembly, and the power screw has a good stop in the center of the part to be removed.

The length of chisels, barbs, crosscuts, punches and other similar tools must be sufficient to safely hold them by hand during work, but not less than 150 mm. It is forbidden to work with a tool that has cracks, burrs, an uneven (knocked down) surface of the striker. Such defects are eliminated using a grinding machine.

Shears for cutting sheet steel, tin, etc. materials must be firmly fixed at the workplace, and the blades must be sharpened well. Scissor handles must not be deformed or mechanically damaged.

Before operating a pneumatic or electric tool (nutrunners, etc.), they are convinced of its serviceability by external inspection and testing of the action at idle. The working part is installed in the spindle only when the tool is disconnected from the mains. Hoses and electrical wires should not be stretched and should not cross the roadways of the production area. Do not hold the tool by rotating or moving parts, even after it has been turned off and the working parts have stopped. The hoses of the pneumatic tool at the junctions are fixed with clamps. Connecting and disconnecting hoses is possible only after closing the taps or valves of the air network, avoiding fractures. Pneumatic hand tools (riveting and chipping hammers, drilling and grinding machines, etc.) must be equipped with effective noise and compressed air exhaust silencers. An electrified tool is connected to the network only with a plug connector. During work, to reduce the risk of accidental electric shock, dielectric mats are placed under the feet of workers.

mykonspekts.ru

1. What work is called metalwork? What kind of work is called locksmith and assembly? Give examples.

MDK 01.01 Basics of metalwork - assembly and electrical work

Locksmith's work is a cold working of metals by cutting, performed manually (file, hacksaw, marking, metal cutting, etc.), or mechanized (hand press, electric drill, etc.) method.

FITTING AND ASSEMBLY WORKS is a production process, as a result of which raw materials and semi-finished products are converted into finished products.

2. What is called a part, assembly, mechanism, machine? Give examples. Which of these elements can be called "assembly"?

A PART is a product made of a material that is homogeneous in name and brand.

ASSEMBLY is a product that is obtained as a result of connecting individual elements together. An assembly can consist of only parts or parts and smaller assemblies. MACHINE - a device that performs mechanical movements in order to convert energy, materials or information

A MECHANISM is the internal structure of a machine that drives it.

ASSEMBLY is a set of jointly working parts, which are separate units, united by one purpose

3. What is the technological process? operation? Transition? Reception? Give examples.

A TECHNOLOGICAL PROCESS is an ordered sequence of interrelated actions that are performed from the moment the initial data arises until the desired result is obtained.

The assembly process is divided into operations, transitions and techniques.

ASSEMBLY OPERATION is a completed part of the assembly process, performed during the manufacture of a product at a separate workplace by one or more workers. The operation may consist of a series of transitions, which are characterized by the constancy of the tool used.

RECEPTION is called a part of the transition, consisting of a number of simple working movements performed by one worker. 4. Name and describe the types of assembly according to the form of organization and the relative position of jobs. Give examples.

There are two BASIC ORGANIZATIONAL ASSEMBLY FORMS: stationary and mobile.

STATIONARY ASSEMBLY is carried out at a stationary workplace, to which all the necessary parts, materials and smaller assembly units are supplied, the assembly of which can be performed at separate workplaces (according to the principle of division of operations), which reduces the process time. MOBILE ASSEMBLY is performed only according to the principle of dismemberment of operations. The product in the assembly process moves from one workplace to another. Workplaces are equipped with the necessary tools and devices. This type of assembly allows assemblers to specialize in certain operations and increase labor productivity. DEPENDING ON THE LOCATION OF WORKPLACES relative to each other, the assembly is distinguished IN-FLOW AND NON-FLOW.

With a mobile in-line assembly, jobs are located in the sequence of operations of the assembly process, and the entire process is divided into separate operations, approximately equal to or multiples of the execution time. Assembled products leave the production line at certain intervals, called tact. In-line assembly can be carried out both with a movable and a fixed object being assembled. In the production of large products, in-line assembly on fixed stands is used, in which a worker or a team of workers perform the same operation, moving from one stand to another. After the last operation, the finished product is removed from each stand.

studfiles.net

- CyberPedia

College of Pskov State University

ON TRAINING PRACTICE

UP.03.01 Locksmith, mechanical and dismantling and assembly work

According to the professional module

Pskov, 2018

Contract for practice with a blue seal (2-3-4 pages)

About the passage of educational practice

Student Dvoenosov Alexander Sergeevich __________________________ (full name)

group _1312-21TOZ9_ had an internship

from "_16__" _____April___2018 to "_27_" ____May____2018

in _ ________ Horns and Hooves LLC _____________________________

_________________________________________________________________________

(full name of organization)

1. The level of theoretical training, readiness to perform work in the specialty ___ The level of theoretical knowledge is quite good, ready to perform work in the specialty. ___________________________________

2. The results of the work ____ the result of the work was completed in full without incidents and violations of safety requirements. ___________________________

3. Degree of responsibility, discipline Responsible, disciplined. The degree of responsibility is quite high.

4. Personal and business qualities ___ able to learn quickly, tactful, result-oriented, hardworking, diligent and punctual.____________________

5. The quality of the practice diary ___ the quality of the diary is good _________

6.Quality of the practice report___Good and timely practice report.____

(excellent/good/satisfactory/poor)

Head of practice from the organization _____technician ________________

Kuzikov V.P.________________________________________________

(position, surname, name, patronymic) (signature)

Ministry of Education and Science of the Russian Federation

FGBOU VO "Pskov State University"

College of Pskov State University

ON TRAINING PRACTICE

UP.03.01 Locksmith, mechanical and dismantling and assembly work

According to the professional module

PM.03 Performance of work by profession "Mechanic for car repair"

Dvoenosov Alexander Sergeevich,

student in the 1st year of specialty SPO

Maintenance and repair of motor vehicles

successfully completed an internship in the professional module PM.03 Performance of work in the profession "Automotive repairman" in the amount of 216 hours from April 16, 2018 to May 27, 2018 in the organization Horns and Hooves LLC, legal address: 180456, Pskov region, pos. Nightingales, Leningrad highway.

Introduction to the enterprise	mastered
Safety briefing	mastered
locksmith work	mastered
Locksmith and measuring tools	mastered
filing metal	mastered
Cutting and felling of metal	mastered
Metal straightening and bending	mastered
markup	mastered
drilling	mastered
Countersinking and reaming holes	mastered
Threading	mastered
Klepka	mastered
Scraping and lapping	mastered
Complex locksmith work	mastered
mechanical works	mastered
Induction training	mastered
Measuring tool	mastered
Turning	mastered
Milling	mastered
Features of work on machines of the drilling and boring group	mastered
Metal processing with abrasive tools	mastered
Complex works	mastered
Dismantling and assembly work	mastered
General vehicle inspection	mastered
Engine, cooling and lubrication systems	mastered
Clutch, gearbox, driveline	mastered
rear axle	mastered
Steering	mastered
Brake system	mastered
Suspension	mastered
Supply system	mastered
electrical equipment	mastered
Work at workplaces at diagnostic posts, checkpoint and daily maintenance areas (EO)	mastered
Work at workplaces at the post (line) of the technical	mastered

Characteristics of the educational and professional activities of the student during the course

Practice leaders from the Pskov State University College: Farafonov A.M. ________________________________________________________

Surname, I.O.

Practice leader from the organization

Master Kuzikov V.P. _______________________________________________

NUMBERING STARTS IN THE CENTER - FROM THIS PAGE, THIS IS PAGE NUMBER 2

Introduction

Locksmith practice aims to acquaint students with the basic technological processes of locksmith work, with equipment, fixtures and tools used in these works, to give students practical skills in performing basic locksmith work.

The guidance of practical training is carried out by masters of industrial training, with experience in this profile and who own the methodology of industrial training. When issuing assignments, the master must explain to the students the purpose and content of the assignment, provide them with operational maps, materials and drawings, familiarize them with devices, etc.; explain the rules and show the methods of performing operations, teach students to establish the technological sequence of plumbing work.

Students are allowed to work only after passing the introductory safety briefing and initial briefing at the workplace.

An introductory briefing on safety rules is conducted by the master under the signature of each student in a special (laced, numbered and sealed) magazine.

The purpose of the practice is the acquisition of practical experience and the formation of general and professional competencies among students within the framework of PM.03 "Automotive mechanic" by type of professional activity - Car repair work.

Objectives of production practice:

Consolidation and systematization of the knowledge gained in the study of the MDK, based on practical participation in the activities of motor transport enterprises and service stations;

Acquisition of professional experience and independent work;

Collection, analysis and synthesis of materials for the preparation of a practice report;

Formation of professional interest, sense of responsibility and respect for the chosen specialty.

The nature of the work performed: Diagnose the car, its units and systems. Perform various types of maintenance work. Disassemble, assemble vehicle components and assemblies and troubleshoot. Prepare reports and technical documentation.

Work practice task:

1) Collect and analyze the following data: the location of the enterprise, the organization of labor of production workers, the composition of posts and sites, the equipment used in maintenance and repair.

2) To study the qualifications of service personnel, the characteristics of the service enterprise and the results of its production activities.

3) Learn safety precautions when performing car repair work.

The theoretical and methodological basis for writing the work was the laws, instructions, literature of modern scientists, the accounting policy of the enterprise, orders, orders, primary and accounting information of the enterprise.

Code	Name of learning outcome
PC 1.1.	Organize and carry out maintenance and repair of vehicles.
PC 1.2.	Carry out technical control during storage, operation, maintenance and repair of vehicles.
PC 1.3.	Develop technological processes for the repair of components and parts.
PC 2.1.	Planning and organizing the maintenance and repair of vehicles.
PC 2.3	Organize the safe conduct of work during the maintenance and repair of vehicles.
PC 3.1.	Diagnose the car, its units and systems.
PC 3.2.	Perform various types of maintenance work.
PC 3.3.	Disassemble, assemble vehicle components and assemblies and troubleshoot.
PC 3.4.	Prepare maintenance documentation.
OK 1.	Understand the essence and social significance of your future profession, show a steady interest in it.
OK 2.	Organize their own activities, choose standard methods and methods for performing professional tasks, evaluate their effectiveness and quality.
OK 3.	Make decisions in standard and non-standard situations and bear responsibility for them.
OK 4.	To search for and use the information necessary for the effective implementation of professional tasks, professional and personal development.
OK 5.	Use information and communication technologies in professional activities.
OK 6.	Work in a team and team, communicate effectively with colleagues, management, consumers.
OK 7.	Take responsibility for the work of team members (subordinates), the result of completing tasks.
OK 8.	Independently determine the tasks of professional and personal development, engage in self-education, consciously plan advanced training.
OK 9.	Navigate in the conditions of frequent change of technologies in professional activity.

Introduction to the enterprise

locksmith work

Safety briefing

Since the legislation provides that the employer is personally responsible for labor safety at work, he is obligated to regularly conduct labor safety briefings with all employees of the relevant enterprise or organization.

Any such briefing, in fact, is one of the forms of training workers in the basics of safe work and behavior at work in general and at each production site separately.

Such briefings (training) regarding labor safety issues should be systematic and carried out with each of the employees of the enterprise (organization) throughout the entire period of their work, both in collective and individual form. Moreover, their implementation in no way depends on the type of activity of the enterprise or organization and their form of ownership.

At large enterprises (organizations), a specially trained specialist may be entrusted by the head with briefings on labor protection and safety. Usually this is an HSE engineer.

All briefings on HSE, HSE, fire safety, as well as the features of production technology are divided into: introductory, primary, periodic, unscheduled and targeted.

The type of briefing depends on its purpose, time and place. Such briefings are required for all employees of enterprises or organizations, including their leaders.

In this case, special attention should be paid to employees with less than a year of experience, as well as employees with extensive experience and length of service. As practice shows, it is these categories of workers that are most susceptible to industrial injuries.

All the rules, safety measures and labor practices during the assembly and disassembly work were brought to me in full against signature. After

which I was introduced to the enterprise and the workplaces where I will carry out repair work during the internship.

Master Kuzikov V.P. was appointed responsible for the passage and control of the practice.

MEASURING INSTRUMENTS special devices used to accurately determine the dimensions and other geometric characteristics of objects. Such devices include calipers, inside and depth gauges (including appropriate micrometers and calipers), feelers, indicator devices, levels and plumb lines, rulers and squares. Micrometers, inside gauges and depth gauges. Some commonly encountered dimensions, such as cylinder diameter, hole diameter, and hole depth, cannot be accurately measured by applying a standard measuring ruler to the part. But you can "take" the diameter or depth of the hole with a caliper-caliper or depth gauge, and then measure the distance taken using a ruler or line measure. To improve the accuracy of such measurements, direct reading calipers equipped with a scale, as well as micrometers and calipers of the same purpose, are used. Micrometers use high-precision, very fine pitch screw threads. Reading on a micrometer is reduced to determining the number of full revolutions and fractions of a drum revolution relative to its zero position. Full revolutions are marked by strokes of a linear scale on a fixed stem, and fractional parts of a revolution are marked by strokes of a circular scale on the end edge of a rotating drum. Most micrometers in English-speaking countries use a 40 thread per inch thread and have 25 divisions on the drum, so that each division of the drum corresponds to a one-thousandth of an inch movement of the stylus. Metric micrometers have similar characteristics. The caliper allows you to read the diameter directly and with high accuracy. The fixed main scale of the British vernier caliper has 50 divisions per inch, while the movable vernier scale has only 20 divisions. The sum of these 20 divisions is equal to the sum of 19 divisions of the main scale. Therefore, when the zero stroke of the vernier scale stops between two strokes of the main scale, only one stroke of the vernier scale can lie exactly opposite any stroke of the main scale. The number of divisions of the vernier scale corresponding to it is equal to the number of twentieth divisions by which the zero stroke of the vernier scale is shifted relative to one stroke of the main scale towards the next stroke. This makes it possible to count the measured diameter with an accuracy of thousandths (inch, centimeter). Styli. In cases where it is required to measure very small distances, for example, only a few times greater than the thickness of the paper, sets of probe plates are used - flat and wedge. Measurements are carried out according to the principle "passes - does not pass". One by one, the plates of the set are inserted into the measured gap until they reach a situation where one of the plates barely enters the gap, and the next one does not enter. The wedge probe is carefully pushed into the gap until it stops, after which its thickness indicated on the front surface of the probe is read. indicator devices. Often important is the degree of eccentricity of the shaft, which should ideally rotate around its geometric centerline. For such control, indicator devices are used. The indicator device is fixed next to the shaft so that its movable measuring rod touches the surface of the shaft being checked. When the shaft rotates, this rod, pressed against the surface of the shaft by a spring, rises and falls in accordance with the beats of the shaft. The movement of the rod is increased by the lever mechanism of the device and is converted into a turn of the arrow on the circular scale of the indicator. Indicator devices show beats measured in thousandths and ten thousandths (inch, centimeter).

Sawing metal.

Cutting and cutting of metal.

Filing is a locksmith operation in which layers of material are removed from the surface of the workpiece using a file.

A file is a multi-bladed cutting tool that provides relatively high accuracy and low roughness of the workpiece (part) surface to be machined.

By filing, they give the parts the required shape and dimensions, fit the parts to each other during assembly, and perform other work. With the help of files, planes, curved surfaces, grooves, grooves, holes of various shapes, surfaces located at different angles, etc. are processed.

Sawing allowances are left small - from 0.5 to 0.025 mm. The error during processing can be from 0.2 to 0.05 mm and in some cases up to 0.005 mm.

A file () is a steel bar of a certain profile and length, on the surface of which there is a notch (cutting). The notch forms small and sharply sharpened teeth, having a wedge shape in cross section. For files with a knurled tooth, the sharpening angle is usually 70 °, the front angle (y) - up to 16°, rear angle (a) - from 32 to 40°.

Single cut files cut wide chips along the entire length of the cut. They are used for cutting soft metals.

Double-cut files are used when filing steel, cast iron and other hard materials, as the cross-cut cuts the chips, which makes it easier to work.

The cutting of metal is carried out with the help of a metalwork chisel and a cross cutter. A chisel made of carbon tool steel is sharpened on an emery or sandstone sharpener. The sharpening angle of the chisel varies depending on the metal for which it is intended: for softer metal, a chisel with a smaller sharpening angle is taken. So, for cutting aluminum and zinc, the chisel sharpening angle will be 35 °, for copper and brass - 45 °, for iron and steel - 60 ° and for cast iron and bronze - 70 °.

After marking with a scriber, the workpiece is placed on an anvil or table steel plate or is well clamped in a large metalwork vice. The chisel is taken with the left hand, set according to the mark and rare strong blows are applied to it with a metalwork hammer. At the same time, the worker must always look at the chisel blade, and not at its head. Kreuzmeysel differs from a chisel in a narrower cutting edge. Kreutzmeysel is used for cutting grooves, cutting keyways and similar work. In order to prevent jamming of the crosscut during operation, its working part has a gradual narrowing from the cutting edge to the handle. The heat treatment of the working and impact parts, as well as the geometric parameters of the cutting part and the procedure for determining the sharpening angles of the cutting part for crosscuts are exactly the same as for the chisel.

The groover is used for cutting lubrication grooves in bushings and sleeves of plain bearings and profile grooves for special purposes. The cutting edges of the groover can have a straight or semicircular shape, which is selected depending on the profile of the groove being cut. The ditcher differs from the chisel and the crosscut only in the shape of the working part. The requirements for heat treatment and the choice of sharpening angles for groovers are the same as for chisels and crosscuts.

Locksmith hammers are used when cutting as a percussion tool to create a cutting force and come in two types - with a round and square striker. The end of the hammer opposite the striker is called the toe; it has a wedge-shaped shape and is rounded at the end. The hammer is fixed on the handle, which is held in the hand during operation, striking the tool (chisel, cross cutter, groover). To securely hold the hammer on the handle and prevent it from jumping off during operation, wooden or metal wedges (usually one or two wedges) are used, which are hammered into the handle where it enters the hammer hole.

Metal straightening and bending.

Markup. drilling.

Straightening is the operation of straightening bent metal. Strip and bar material is driven with round-faced steel hammers. Blows are applied to a convex place, periodically turning the straightened workpiece. Thin sheets of th metal are ruled with wooden hammers (mallets), blows are applied from the edges of the sheet towards the bulge. In order not to damage them when straightening parts with treated surfaces, straightening is carried out with special hammers, in the strikers of which rods of soft materials are inserted: copper, brass, lead. In the absence of special hammers, dressing is carried out with steel hammers, but through a soft gasket. Large section bar material and shafts are straightened on screw presses. Places with a sharp bend must be heated before editing, otherwise the metal may crack. Flexible from a flat workpiece get curved parts. Bench bending is carried out in a vice or in special devices with hammers, levers. To obtain the desired shape of the part, various inserts are used that have a profile according to the shape of the part to be bent. Pipes are bent using pipe benders. They have two rollers: a fixed one, around which the pipe bends, and a movable one, located on the lever, which bends. To avoid dents during bending, the pipe is filled with dry sand. With a large amount of work on straightening sectional metal, straightening is carried out on presses, and sheets of metal are straightened on rollers. Rollers have two rolls rotating in different directions, or a series of rolls. Curved sheet, passing between the rolls, straightens. In mass production, bending is done with bending dies.”

Marking is the drawing of borders on the surface of the workpiece in the form of lines and points corresponding to the dimensions of the part according to the drawing, as well as axial lines and centers for drilling holes. Marking is planar and spatial. The blanks are marked on a special cast-iron plate, called marking, its upper plane was strictly horizontal.

When marking, use various marking tools. One of the most necessary tools used is: scribers, marking compasses, inside gauges, calipers and center punches. In some cases, another high-performance tool is also used for marking: templates, universal thickness gauges, etc.

Marking tool.1 - scriber; 2 - marking compasses; 3 - punch: 4 - square

Scribers and squares are used for drawing marks when marking electrical structures. They are made from tool steel. Scriber diameters - from 3 to 8 mm, length 150 - 200 mm. After hardening of the working part of the rod, the scribers are sharply sharpened to a length of 20–30 mm. Marking compasses and vernier calipers are used to mark measuring instruments. To mark the center of the intersection of the marks, a center punch is used, a cylindrical rod, the middle part of which is knurled for ease of support. The working ends of the center punch are sharpened and hardened. One end is sharpened at an angle of 60 °, and the other is slightly rounded. Punching is done with a hammer blow. To increase labor productivity, special punches are used, for example, automatic or electric.

Drilling is an operation to form through and blind holes in a solid material, performed using a cutting tool - a drill. There are manual drilling - manual pneumatic and electric drilling devices (drills) and drilling on drilling machines. Hand-held drilling devices are used to obtain holes up to 12 mm in diameter in materials of low and medium hardness (plastics, non-ferrous metals, structural steels, etc.). For drilling and processing holes of larger diameter, increasing labor productivity and processing quality, desktop drilling and stationary machines are used - vertical drilling and radial drilling.

One of the types of drilling is reaming - an increase in the diameter of a previously drilled hole. Drills are used as tools for reaming holes, as well as for drilling. It is not recommended to drill holes obtained in the workpiece by casting, forging or stamping. Such holes have different hardness over the surface of the hole due to the scale formed during casting, as well as due to the uneven concentration of internal stresses in the metal in different parts of the surface of the holes obtained by forging or stamping. The presence of places with uneven and increased surface hardness leads to a change in the radial loads on the drill during hole processing, which leads to a displacement of its axis, and also causes drill breakage. Hole processing by drilling and reaming allows to obtain the dimensional accuracy of the machined hole up to the 10th grade and the roughness of the machined surface up to Rz 80.

Thread cutting.

Countersinking is an operation associated with the processing of pre-drilled, stamped, cast or other holes obtained by other methods in order to give them a more regular geometric shape (eliminate deviations from roundness and other defects), as well as to achieve higher accuracy compared to drilling (up to 8th grade) and lower roughness (up to Ra 1.25). Countersinking is carried out either on desktop drilling machines (with small hole diameters) or on stationary drilling equipment installed on the foundation. Manual drilling equipment for countersinking is not used, since it cannot provide the required accuracy and surface roughness. The types of countersinking include countersinking and countersinking.

Reaming is an operation for processing previously drilled holes with a high degree of accuracy (up to grade 6) and low roughness (up to Ra 0.63). Reaming processing is performed after preliminary drilling, reaming and countersinking of the hole with reamers, which are divided into rough and finish, manual and machine. Deployment is carried out both manually and on machines, as a rule, stationary. The design of the tool is selected depending on the processing method used.

Basic rules for reaming holes:

It is necessary to strictly observe the amount of the deployment allowance, guided by the corresponding table;

Manual reaming should be performed in two steps: first roughing and then finishing;

In the process of reaming a hole in a steel billet, it is necessary to generously lubricate the surface to be treated with emulsion or mineral oil, cast iron billets should be reamed dry;

Manual reaming should be carried out only clockwise to avoid scuffing of the hole walls with chips;

During processing, the reamer should be periodically cleaned of chips;

The accuracy of processing reamed holes should be checked with calibers: cylindrical - through and through; conical - according to the maximum risks on the caliber. The expanded conical hole is allowed to be checked with a “pencil” control pin;

Drilling and reaming holes on a drilling machine with a machine reamer must be done from one installation of the workpiece, changing only the processing tool.

Threading is the formation of a helical surface on the outer or inner cylindrical or conical surfaces of a part.

Cutting a helical surface on bolts, rollers and other outer surfaces of parts can be done manually or by machine. Hand tools include: round split and continuous dies, as well as four- and hexagonal plate dies, pipe threading dies. For fastening the dies, die holders and screw caps are used. The round die is also used for machine threading.

The number of chip holes r depends on the chip thickness az removed by the teeth of one hole, the angle of the intake cone φ and the thread pitch t: With an increase in the number of chip holes r, the chip thickness ag decreases and vice versa. Depending on the diameter of the thread being cut, the number of chip holes ranges from 3 to 14.

Machine thread cutting can be performed on lathes with thread cutters, combs, thread-cutting heads with radial, tangential and round combs, swirl heads, as well as on drilling machines with thread-cutting heads, on milling machines with thread cutters and on thread-grinding machines with single-thread and multi-thread wheels.

Obtaining an external threaded surface can be provided by rolling it with flat dies, round rollers on thread rolling machines. The use of thread rolling heads with axial feed allows you to roll external threads on drilling and turning equipment.

Riveting is the production of permanent joints using rivets used in the manufacture of metal structures (trusses, beams, various containers and frame structures). The rivet is a cylindrical rod made of ductile metal, at one end of which there is a head, called a mortgage. During the riveting operation, on the second side of the rod, which is installed in the holes of the workpieces to be joined, a second rivet head is formed, which is called the closing head. Mortgage and closing heads are mainly semicircular and countersunk. The need to use plastic metal for the manufacture of rivets is due to the fact that its heads are formed as a result of plastic deformation of the rivet rod. When making riveted joints, rivets should be selected from the same material from which the parts to be joined are made. This prevents the appearance of galvanic couples, leading to corrosion at the point of contact between the rivet and the part. The riveting process consists of two stages - preparatory and actual riveting.

The preparatory process of riveting includes drilling or punching a hole for the rivet and forming a recess in it with the help of countersinking for the mortgage and closing heads, if necessary. The riveting itself includes the installation of a rivet in a prepared hole, the stretching of the riveted blanks, the formation of a closing head and cleaning after riveting. Depending on the nature of the riveted joint, riveting is performed in a cold (without heating) and hot (with preheating of the rivet to a temperature of 1000 ... 1,100 ° C) method. In practice, hot riveting is used in cases where steel rivets with a diameter of more than 12 mm are used.

Types of rivets and rivet seams

Most often, during installation work, types of rivets with a semicircular and countersunk head are used. Due to the fact that countersunk rivets do not securely connect the parts at the riveting site, their use is limited. This type of rivet is used only in cases where their heads, according to the operating conditions of the structure, should not protrude above its surface. Depending on the purpose and operating conditions, it is possible to use rivets with other forms of heads.

The choice of rivet sizes depends on the thickness of the parts to be joined by the riveting. The diameter of the rivet should, as a rule, be equal to the total thickness of the parts to be joined. The length of the rivet rod is determined taking into account the formation of the closing head, the shrinkage of the rod during riveting, and the need to fill the gap between the rivet rod and the wall or the hole for it.

Scraping and lapping.

General information about scraping and grinding. Lapping and abrasive-lapping materials hard materials - emery, corundum and similar powders soft materials - powders from oxides of chromium, iron, aluminum, tin. abrasive pastes. Grinding techniques for various surfaces. In addition, new methods of sharpening and sharpening drills, combined thread-cutting tools, as well as high-performance tools for scraping and grinding various surfaces, etc. are described. Fitting operations - filing, scraping and lapping are aimed at removing metal from the surface of the workpiece to give it the required shape and a given degree of surface finish. With precise scraping, it is recommended, in order to increase labor productivity, to combine scraping itself and lapping with coarse GOI paste. When scraping, cast-iron plates are used to check the surfaces of flat parts for paint, flat and trihedral rulers to check the flatness of the surface, prisms, plates in the form of a rectangular parallelepiped, control rollers , probes and other tools for quality control of scraping and lapping. In addition to the tools mentioned, brushes and cleaning materials should be used. Scraping with lapping with GOI pastes (coarse, medium, thin) is performed in the following sequence: rough scraping, washing with kerosene and drying with rags, applying a thin layer of paste, lapping resistance

There are locksmith and repair works, which consist in replacing or repairing damaged and worn parts, manufacturing missing parts, assembling components, mechanisms and even the whole machine, performing fitting and adjusting the assembled mechanisms and testing the finished machine. Each locksmith has his own workplace - a small section of the workshop's production area, where there is all the necessary equipment: hand tools for metal processing, instrumentation, auxiliary devices.

The main equipment of the workplace for metalwork processing is a metal workbench with a vice fixed on it, and a set of necessary working and measuring tools and devices. In order to be able to move a part or components weighing more than 16 kg at the workplace, it must be serviced by cranes or hoists. To perform assembly or disassembly work, workplaces are equipped with stands, conveyors, roller tables, special carts or other transport devices.

Marking, cutting, straightening and bending

Metalworking includes such operations as marking, cutting, straightening and bending, as well as cutting metal with a hacksaw and scissors, cutting internal or external threads, scraping and joining parts by soldering or gluing.

Workpiece marking

Marking is the process of applying special lines (marks) to the surface of the workpiece, which, according to the requirements of the drawing, determine the places or contours of the part to be processed. The markup creates the necessary conditions for obtaining a part of a certain shape and the desired dimensions, removing metal allowance from workpieces to specified boundaries and for maximum savings in materials. The history of artistic processing of metal knows many examples when, with the help of marking and subsequent engraving or notching, real works of art were obtained.

Metal cut

The cutting process is the removal of the metal of the workpiece with a chisel and a hammer. It is produced in a vise, on an anvil or on a plate.

Straightening and bending of the product

Editing is an operation that eliminates various imperfections in the shape of the workpiece (irregularities, curvature). Manual dressing is done with a hammer on a straightening anvil or plate, and machine dressing is done on straightening machines.

With the help of bending, the workpiece is given a given shape (in the manufacture of loops, staples, rings, brackets and other products). Like any other metal processing, manual bending can be done in a vice using a bench hammer and all kinds of devices. Mechanized bending is carried out on bending machines and bending presses with manual and mechanized drives.

Metal cutting

For cutting metal, a special hacksaw or scissors (metal guillotine) can be used. Sheet metal is cut with manual or mechanical scissors, pipes, and profile material is cut with manual or mechanical hacksaws for metal. Pipe cutters are used for cutting pipes, as well as circular and band saws.

The metal cutting technique includes such an operation as filing. This process consists in removing a layer of metal from the surface of the workpiece in order to give it more accurate dimensions and the necessary surface cleanliness. Sawing is done with files.

In the metalworking of metals, an operation such as drilling can be performed - obtaining cylindrical holes with a drill. Drilling can be carried out on many metal-cutting machines: drilling, turning, revolving and others. The most suitable for this operation are drilling machines. During assembly and repair work, drilling is often done using portable drills: pneumatic, electric and manual.

The manufacture of metal parts may include threading - the process of forming spirals on the inner and outer cylindrical and conical surfaces of blanks that serve to connect parts. Such parts form detachable connections. Threads on bolts, screws and other parts are cut mainly on machine tools. When assembling and repairing units, as well as during installation work, they resort to manual threading using taps and dies.

The technologies of manual metal processing attach great importance to scraping - the operation of processing the surfaces of metal parts, during which the metal layer is scraped off with a special cutting tool - a scraper. Scraping is used to ensure precise contact of rubbing surfaces without disturbing their lubrication. This operation is performed manually or on special machines.

In locksmith work, metal finishing is often carried out using lapping, which is performed using hard grinding powders applied to special lappings made of gray cast iron, copper, mild steel and other materials. The lap in shape must match the shape of the surface to be treated. By moving the lap along the surface to be treated, a very thin (0.001-0.002 mm) layer of roughness is removed from it, which helps to achieve tight contact between the mating parts.

Permanent connections

To obtain permanent joints from metal parts, metal processing methods such as riveting and soldering (soldering) are often used. Riveting is a method of obtaining an integral connection from two or more parts using rivets. Riveting can be done with a pneumatic hammer, a manual metalworker's hammer or on special riveting machines.

Soldering parts

Soldering is the process of joining metal parts with a molten alloy called solder, which has a melting point much lower than the metal of the parts to be joined. Metal processing at home often includes soldering - it is widely used in repair work, as well as for sealing cracks, eliminating leaks of liquids from vessels, etc.

4. Defective equipment

Fault detection is the definition of machine malfunctions during operation or repair. There are two stages - fault detection of the assembled machine and after its disassembly.
Fault detection of a machine or apparatus is one of the most critical operations, since undetected malfunctions can lead to the destruction of the machine in operation, an accident, and an increase in the duration and cost of work during repeated repairs.
Electrical equipment is characterized by the presence of two parts - electrical and mechanical. When fault-finding the mechanical part of electrical equipment, they check the condition of the fasteners, make sure that there are no cracks in one or another part, determine wear and tear and compare it with permissible standards, measure air gaps and compare with tabular values, etc.
All detected deviations from the norms are recorded and entered in the list of defects or a repair card, the forms of which are different at different plants, but the content is almost the same.
Malfunctions in the electrical part of a machine or apparatus are hidden from human eyes, so they are more difficult to detect. The number of possible faults in the electrical part is limited to three:
breakage of the electrical circuit;
the short circuit of individual circuits between themselves or the circuit of the circuit (circuits) on the body;
the closure between each other of the turns of the winding (the so-called inter-turn or turn closure).
These faults can be identified using the following four methods:
- test lamp or resistance method (ohmmeter);
- method of symmetry of currents or voltages;
- millivoltmeter method;
- electromagnet method.
Consider the definition of faults in the assembled machine or apparatus.
An open in a winding without parallel circuits can be determined by using a test lamp. If there are two or more parallel branches in the winding, a break is determined with an ohmmeter or an ammeter and a voltmeter. The obtained value of the resistance of the winding (for example, the armature winding of a DC machine) is compared with the calculated or passport value, after which a conclusion is made about the integrity of the individual branches of the winding. Breaks in multi-phase machines and devices that do not have parallel branches can be determined by the current or voltage symmetry method, but this method is more complicated than the previous one.
It is somewhat more difficult to determine a break in the rods of squirrel-cage rotors of asynchronous electric motors. In this case, resort to the method of current symmetry.
Experience in determining breaks in rods is as follows. The rotor of the electric motor is braked and a voltage reduced by 5 ... 6 times compared to the rated voltage is supplied to the stator. An ammeter is included in each of the phases of the stator winding. With good stator and rotor windings, the readings of all three ammeters are the same and do not depend on the position of the rotor. When the rods break in the rotor, the readings of the instruments are different, most often two ammeters show the same currents, and the third shows a lower current. When the rotor is slowly rotated by hand, the readings of the instruments change, the reduced current value will follow the rotation of the rotor and goes from one phase to another, then to the third, etc.
This is explained by the fact that when the rotor turns, the damaged rods move from the zone of one phase to the zone of another. A stalled induction motor is like a transformer in short circuit mode. Breakage of the rod is equivalent to transferring the damage zone from the short circuit mode to the load mode, which leads to a decrease in the current in the stator winding in that part of it that interacts with the damaged rod.
If several rotor rods break, the readings of all ammeters may be different, but, as mentioned above, they will cyclically change and follow one after the other (passing through the phases of the stator winding) with slow rotation of the rotor. Different readings of ammeters, independent of the rotation of the rotor, indicate damage or defects in the stator winding, but not the rotor.
The location of the break in the windings of the rotors of squirrel-cage motors is determined using an electromagnet. The rotor, mounted on an electromagnet, is covered with a sheet of paper, on which steel filings are poured. When the electromagnet is turned on, the sawdust is located along the entire rods and is absent in the break zone.
Breaks in the armature windings of DC machines are determined using an ohmmeter (millivoltmeter).
The closure of individual electrical circuits of electrical equipment to the housing or to each other is determined using a test lamp. Often in this case, megohmmeters are used. The latter should be given preference, since they are easy to determine the circuit with a relatively high resistance at the point of contact between the circuits or with the case.
The short circuit between the sections lying in different layers of the grooves of the section armatures on the body is determined using an ohmmeter (millivoltmeter).
The coil circuit in multi-phase electrical machines and devices is determined by the method of symmetry of such and voltages or by special devices, for example, the EJI-1 type.
So, turn short circuits in the windings of three-phase electric motors are determined at idle their operation using the current symmetry method (the readings of all three ammeters included in each phase of the stator winding should be the same in the absence of turn short circuits), and turn short circuits in the stator windings of synchronous generators are determined at idle using the voltage symmetry method (the readings of all three voltmeters connected to the stator winding terminals must be the same).
When determining turn short circuits in the windings of three-phase transformers, both the current and voltage symmetry method is used.

Rice. 7. Scheme for determining turn short circuits in equipment coils.
Turn short circuits in the windings of single-phase electrical machines and transformers are determined with an ohmmeter or ammeter. When determining turn short circuits in the excitation coils of DC machines, it is advisable to use low-voltage alternating current rather than direct current to increase the sensitivity of the test by selecting the appropriate instruments (ammeter and voltmeter).
It should be noted that a turn short circuit in the windings of electrical equipment operating on alternating current is accompanied by a sharp increase in current in the damaged winding, which, in turn, leads to a very rapid heating of the winding to unacceptable limits, the winding starts to smoke, char and burns.
The place of turn circuits in the stator windings of AC electrical machines is determined using an electromagnet. The place of turn short circuits in the armature windings of DC machines is determined with an ohmmeter (millivoltmeter).
Usually damaged coils of transformers are not defective, but if necessary, the electromagnet method can be used.
The fault detection of DC and AC machines and transformers during repair is described in detail in the workshop on installation, operation and repair of electrical equipment.

The main types of locksmith processing include:

marking, cutting, straightening and bending, cutting, filing, drilling, countersinking, countersinking, reaming, threading, riveting, scraping, lapping and finishing, etc.

markup

Marking is the operation of applying marking marks to the workpiece or workpiece that define the contours of the parts or the places to be processed.

Marking equipment and tools

marking plate cast from gray cast iron.

Scribers are used to draw lines on the marked surface. Scribers are made from steel U10 or U12; for marking on a steel, well-finished surface, brass scribers are used, and risks are applied to aluminum with a pencil.



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Kerner It is used for drawing recesses (cores) on pre-marked lines. Cores are applied so that the lines are not erased during the processing of the part.

Marking compasses used for marking circles and arcs, dividing segments, circles, geometric constructions and for transferring dimensions from measuring rulers to a part.

Marking calipers are used for precise marking of straight lines, centers and circles of large diameters.

Reismas is the main tool for spatial markup. It serves to draw parallel vertical and horizontal lines, as well as to check the installation of parts on the plate.

Before marking, the surface of the part must be cleaned of dirt, scale, and traces of corrosion. Cleaning is carried out with metal brushes. After cleaning, the surface of the part is painted. For painting use dry chalk or chalk diluted in water with the addition of wood glue; a solution of copper sulfate (three teaspoons per glass of water), as well as quick-drying varnishes and paints.

felling

felling a locksmith operation is called, in which excess layers of metal are removed from the surface of a part or workpiece or the workpiece is cut into pieces.

Cold chisel made of U7A tool steel; U8A; 7HF; 8HF.

for cutting hard materials (steel, cast iron, bronze) - 70º;

for cutting steel of medium hardness - 60º;

for cutting brass, copper - 45º;

for cutting aluminum alloys - 35º.

The value of the taper angle is checked by a template, which is a plate with angular cutouts 70; 60; 45 and 35º (Figure 14a, b).

Kreutzmeisel differs from a chisel in a narrower cutting edge; it is used for cutting narrow grooves, keyways, etc. For cutting profile grooves - semicircular, dihedral and others - they use groovers(Figure 13c) - special crosscuts, differing from them only in the shape of the cutting edge.

As a percussion instrument

Hammers by weight are from 200 to 1000 g.

Metal dressing

Edit is an operation for straightening metal, blanks and parts that have dents, bulges, waviness, warping, curvature, etc.

Cold hand dressing is carried out on correct plate or anvil.



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Editing thin sheets is done with mallets. Very thin sheets are smoothed on the correct plates with smoothers.

Profile metal (angle, channel, hollow shafts, thick sheet steel) is corrected with heating with a blowtorch or welding torch to a cherry red color.

bending- this is a method of metal forming by pressure, in which a workpiece or part of it is given a curved shape along a given contour.