Basic operations when performing metalwork assembly work. Types of plumbing work and characteristics
Metalworking technology contains a number of basic operations, such as marking, chopping, straightening and bending metals, cutting metals, filing, drilling, countersinking, countersinking and reaming holes, threading, riveting, lapping and finishing, soldering, etc. Most of these operations include for metal cutting processing.
3.1 Marking
Marking is the operation of applying lines (scores) to the surface of the workpiece, showing, according to the drawing, the contours of the part or place to be processed. Markup is divided into:
Linear (one-dimensional) – along the length of rods, rolled products, strip steel,
Planar (two-dimensional) – for sheet metal blanks,
Spatial (volumetric, three-dimensional) – for volumetric workpieces.
Special marking tools include scribers, center punches, marking compasses, and surface planers. In addition to these tools, hammers, marking plates and auxiliary devices are used: pads, jacks, etc.
| Figure 6 Scribbler | Scribblers (Figure 6) are used to draw lines on the marked surface of the workpiece. They are made from tool steel U10 or U12 (hardness HRC 58-62). Core punches (Figure 7) are used to apply recesses (cores) to previously |
| Figure 7 Kerner |
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| marked lines so that the lines are clearly visible and are not erased during the processing of parts. A center punch is a rod made of tool carbon steel U7, U8 (HRC 52-57) with a length of 100-160 mm and a diameter of 8-12 mm. The sharpening angle is usually 60°, for more precise markings - 30-45°, for the centers of future holes - 75°. Marking (metalwork) compasses are similar in design to drawing compasses. Thicknesser (Figure 8) is used for applying parallel vertical and horizontal marks. Recently, a height gauge with a sharp tip has been used more often. Planar and especially spatial marking of workpieces is carried out on marking plates. The marking plate is a cast iron whose horizontal working surface and side edges are very precisely machined. A template is a device used to make parts or check them. |
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after processing. Pattern marking is used in the production of large batches of identical parts. It is advisable because labor-intensive and time-consuming marking according to the drawing is performed only once during the manufacture of the template. All subsequent operations for marking blanks consist of copying the outlines of the template. In addition, the manufactured templates can be used to control the part after processing the workpiece.
3.2 Straightening and bending of metals
Straightening is an operation to eliminate defects in workpieces and parts in the form of concavity, convexity, waviness, warping, curvature, etc. Its essence lies in the compression of the convex layer of metal and the expansion of the concave one.
The metal is straightened both in cold and heated states. The choice of one or another straightening method depends on the amount of deflection, size and material of the workpiece (part).
Straightening can be done manually (on a steel or cast iron leveling plate) or machine (on leveling rollers or presses).
The correct slab, like the marking slab, must be massive. Its dimensions can be from 400400 mm to 15003000 mm. The slabs are installed on metal or wooden supports, ensuring the stability of the slab and its horizontal position.
To straighten hardened parts (straightening), straightening heads are used. They are made of steel and hardened. The working surface of the headstock can be cylindrical or spherical with a radius of 150-200 mm.
Manual straightening is carried out with special hammers with a round, radius or insertable soft metal striker. Thin sheet metal is straightened with a mallet (wooden hammer).
Check the edit “by eye”, and when high requirements to the straightness of the strip - with a straight edge or on a test plate.
Shafts and round workpieces of large cross-section are straightened using a manual screw or hydraulic press.
Metal bending is used to give the workpiece a curved shape according to the drawing. Its essence lies in the fact that one part of the workpiece is bent relative to the other at a given angle. Manual bending is done in a vice using a hammer and various devices.
Bending of thin sheet metal is done with a mallet.
When plastic deformation of metal occurs during bending, the elasticity of the material must be taken into account: after the load is removed, the bending angle increases slightly.
The manufacture of parts with very small bending radii is associated with the danger of rupture of the outer layer of the workpiece at the bending point. The size of the minimum permissible bend radius depends on mechanical properties workpiece material, bending technology and surface quality.
Pipe bending is done with or without filler (usually dry river sand). The filler protects the pipe walls from the formation of folds and wrinkles (corrugations) in places of bending.
studfiles.net
GBPOU RM "Saransk Polytechnic College" Ruzaevka.
Notes for the lesson “Basic plumbing operations in welding production»
File: lesson notes
Routing No. 1 PM05. “Performing work according to the worker’s profession”
Subject: General information about metalworking operations used in assembly and welding production.
Purpose: To become familiar with the basic metalworking operations used in the manufacture of a welded product.
Lesson type – practical lesson.
Lesson teaching method - partially search
Lesson objectives:
Educational:
The student must be able to:
Correctly determine the loads on welds; - draw up diagrams of loads on welds.
Educational:
To develop in students the ability to independently accept technical solutions, attentiveness, respect for the chosen profession.
Developmental:
To form in students an information-professional worldview and a desire to learn new things.
To stimulate interest in the discipline, to reveal the relationship of the discipline with others professional disciplines.
The form of training is group.
The teaching method is practical.
Material, technical and didactic equipment of the lesson: - multimedia installation, electronic textbook materials, guidelines for completing the work
During the classes
1. Updating basic knowledge, abilities, skills and personality traits
Checking the availability of students according to the payroll - report; - Setting lesson goals; - Issuing individual assignments for completion practical work.
2. Formation of new knowledge, abilities, skills and personality traits
Metalworking is the processing of metals, usually as a complement to machining or as a finishing touch to manufacturing. metal products connecting parts by welding, assembling machines and mechanisms, as well as their regulation. Locksmith work is performed using manual or mechanized locksmith tools or on machines.
Locksmith work is used in various types production and they are united by a single technology for their implementation.
Basic plumbing operations can be divided into several groups according to their purpose:
Fig. 1 Main groups of plumbing operations
The operations of each group have their own accuracy class, so in the process of work you should clearly understand what processing accuracy is necessary in the final result of metalworking. In enterprises or workshops that produce a variety of welded products, the versatility of performing various metalwork operations is required.
Quality welded joint largely depends on the preparation of the metal and the assembly of the product for welding.
The base metal intended for the manufacture of welded structures is cleaned, marked into individual parts, and the necessary edge profiling is performed.
Cleaning is an operation that is used to remove from the metal surface preservatives, contaminants, cutting fluids, rust, scale, burrs and burrs that complicate the welding process, cause defects in welds and prevent the application of protective coatings.
Straightening is an operation to eliminate deformations of rolled sheet steel and profile metal, straightening blanks of parts that have dents, bulges, waviness, warping, curvature, etc. The metal is straightened both in a cold and heated state. The choice of method depends on the deflection, size and material of the product.
Marking is the transfer of full-size dimensions of a part from a drawing to metal. In addition, when welding, marking lines (marks) are applied to the surface of the workpiece, which determine the installation location of individual parts when assembling components and structures.
There are:
1. Planar markings.
2. Spatial marking.
Metal cutting is the operation of separating metal into parts.
Depending on the shape and size of the workpieces or parts, cutting is carried out manually - with hand scissors, hand hacksaws, lever scissors. Cutting can also be carried out with oxygen torches along the intended contour line of the part manually or with gas-cutting machines special purpose. Cutting on mechanized machines is more productive and has high quality cutting However, it is advisable to perform mechanical cutting when preparing parts of the same type, mainly with a rectangular cross-section.
Bending is a method of processing metal by pressure, in which a workpiece or part thereof is given a curved shape.
Chopping is a metalworking operation in which, using a cutting tool (chisel, etc.) and a percussion tool (machinery hammer), excess layers of metal are removed from the surface of a workpiece or part or the workpiece is cut into pieces. In addition, chopping is used when it is necessary to remove burrs, defects or remove part of the metal.
Filing is the removal of a layer of metal from the surface of a workpiece using a special cutting tool - a file.
Using files, a mechanic gives parts the required shape and size, fits parts to each other, prepares the edges of parts for welding and performs other work.
3. Summing up the lesson (5 min)
Monitoring the completion of the task by all students in the group, analyzing the performance of the work, making comments as the work progresses and obtaining specific results.
4. Homework (5 min): material from the electronic textbook on the topic, repetition of previously studied material.
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Basic metalworking operations and tools used
Straightening is an operation through which unevenness, curvature or other imperfections in the shape of workpieces are eliminated.
The main equipment for manual straightening of metals are steel or cast iron leveling plates. Steel hammers with a round striker are used as a tool for manual straightening; Hammers made of soft materials are used for straightening finished surfaces, as well as for straightening workpieces and parts made of non-ferrous metals and alloys.
Chopping is an operation of cold metal cutting. The impact tools for chopping are metalworking and pneumatic hammers, and the cutting tools are chisels, cross-cutters and groovers.
Chisel. The metalworking chisel is made of tool carbon steel. It consists of three parts: shock, middle and working.
The striking part is made tapering upward, and its top (the striker) is rounded; The middle part of the chisel is held during chopping; the working part is wedge-shaped. The sharpening angle is selected depending on the hardness of the material being processed.
For the most common materials, the following sharpening angles are recommended: for hard materials(hard steel, cast iron) – 70°;
for materials of medium hardness (steel) – 60°;
for soft materials (copper, brass) – 45°;
for aluminum alloys – 35°.
Kreutzmeisel. To cut out narrow grooves and grooves, use a chisel with a narrow cutting edge - a cross-section. Such a chisel can also be used to remove wide layers of metal: first, grooves are cut with a narrow chisel, and the remaining protrusions are cut off with a wide chisel.
Locksmith's hammers. Bench hammers are used for chopping metals and come in two types: with a round head and with a square head. The main characteristic of a hammer is its mass. For chopping metals, hammers weighing 400...600g are used.
To make work easier and increase productivity, mechanized tools are used. Among them, the most common is the pneumatic chipping hammer.
Metal cutting
For cutting metal, hacksaws are used, the cutting part of which is the blade. The choice of blade depends on the material of the workpiece, its shape and size. Pipe cutters are used to cut pipes manually. For cutting sheet metal up to 1.5 mm thick, straight cutting or for figure cutting scissors. The wire is cut with needle-nose pliers or power scissors.
Filing
Filing is an operation in which a layer of metal is removed from the surface of the workpiece using a cutting tool - a file.
The purpose of filing is to give parts the required shape, size and specified surface roughness.
Files vary in the number of cuts, section profile and length.
According to the number of teeth cut per 10 mm of length, files are divided into 6 classes (0, 1, 2, 3, 4.5).
Depending on the work performed, files are divided into the following types: metalworking files - general purpose and for special works, machine, needle files and rasps.
1) General purpose metalworker’s files according to GOST 1465-69 are manufactured in eight types: flat, square, triangular, semicircular, rhombic and hacksaw with a length of 100 to 400 mm with a notch No. 0-5.
Bench files for special work are intended for removing very large allowances when filing grooves, shaped and curved surfaces; for processing non-ferrous metals, non-metallic materials, etc. Depending on the work performed, files of this type are divided into grooved, flat with oval ribs, bars, double-ended, etc.
2) Machine files according to their design are divided into rod, disk, shaped heads and lamellar. During operation, the rod file is subject to a reciprocating motion, the disc files and shaped heads are subject to rotational motion, and the plate files are subject to continuous movement along with a continuously moving metal strip.
3) Needle files according to GOST 1513-67 are manufactured in ten types: flat, triangular, square, semicircular oval, hacksaw, etc., 40, 60 and 80 mm long with a notch of 5 numbers. The length of the file is determined by the length of the working part. The edges of flat files have a single or double notch. The sides and top edge of hacksaw files have a double notch.
Needle files are used for filing small surfaces and bottlenecks, inaccessible for processing with bench files.
4) Rasps, in accordance with GOST 6876-54, are manufactured in several types: general purpose, shoe and ungulate.
Depending on the profile, general purpose rasps are divided into flat, round and semicircular with notch No. 1-2 and length from 259 to 350 mm.
Hole machining
Drilling is carried out on drilling machines or using hand-held devices. The main cutting part is the drill, which has two cutting edges. When drilling holes with a diameter of more than 20 mm, pre-drill the holes with a drill of a smaller diameter, then drill it to size with a drill of a larger diameter.
After drilling, stamping, casting, they are countersinked to obtain a more accurate hole. Depending on the accuracy and purpose of the holes for their processing, countersinks of two numbers are made: No. 1 - for preliminary processing of holes and No. 2 - for final processing. Structurally, countersinks are of two types: solid, processing holes from 10 to 40 mm, and mounted ones, from 32 to 80 mm.
Reaming is used to obtain holes with a more precise shape and low roughness. The operation is carried out using a multi-bladed tool - a reamer. Depending on the shape, cylindrical and conical reamers are distinguished. By method of application - manual and machine, by design - solid, mounted, sliding (adjustable) and combined, right and left.
Manufactured part:
Part sketch:
Progress:
1. Processing the sharp corners of the workpiece with a hog file.
2. Applying markings using a caliper and a height gauge.
3. Punching along the contour of the marking for drilling.
4. Drilling.
5. Beating off excess material with a chisel.
6. Processing with files until the required dimensions are obtained.
7. Drilling out the central hole and thread. Threading,
8. Polishing with sandpaper.
Welding section
infopedia.su
Plumbing operation - Great Encyclopedia of Oil and Gas, article, page 1
Locksmith operation
Page 1
Locksmith operations must be carried out very carefully, using only well-sharpened tools.
Mechanical operations performed on a conveyor are mechanized whenever possible.
Metalworking operations involve processing and fitting parts manually using simple tools and devices. For many years, locksmith operations were not mechanized and were therefore very labor intensive.
Mechanical assembly operations involve processing and fitting parts using simple tools. The need for plumbing operations is caused by imperfection machining parts and lack of interchangeability of parts during assembly.
The listed plumbing operations are preparatory; they are performed before assembling parts into assemblies.
An electrician performs plumbing operations for repairing electrical equipment.
An electrician performs plumbing operations for repairing electrical equipment using metalworking (Fig. 2), metal-cutting (Fig. 3) and measuring (Fig. 4) tools.
A metalworking operation is a completed part of the technological process of processing a workpiece or part, performed simultaneously and continuously before moving on to processing the next workpiece or part. The concept of metalworking operation is conditional, since the same metalworking operation, carried out at different enterprises or under different conditions, is defined differently from the point of view of the technology for its implementation.
The most common plumbing operations during pipe preparation for assembly are threading and bending.
When performing metalworking operations on processing individual parts, they must be firmly secured in a vice. The bench vise must be in full working order, firmly clamp the products, and there should be no noticeable wear on the notches on the jaws.
Many metalworking operations in electrical machines differ significantly from similar operations in mechanical engineering.
Many metalworking operations in electrical machines differ significantly from similar operations in general mechanical engineering.
The variety of metalworking operations leads to the improvement and specialization of clamping devices, some of which are shown in Fig.
Pages: 1 2 3 4
www.ngpedia.ru
- Metalwork and tool work
Metalworking operations before assemblyMetalwork and tool work
Metalworking operations before assemblyBefore assembling the device, the completeness, quality of workmanship and degree of readiness of the parts received for assembly are determined. Having made sure that the parts comply with the drawing and the technological process, they begin their metalworking.
Their machining involves dulling sharp edges, removing burrs, threading threads, assembling individual units installed in assembled form, creating the required connection and smooth running of parts and units, scraping or grinding the supporting planes and planes of connection with the body of the device. Most of the listed works are performed using conventional plumbing techniques.
In many cases, the processing of hardened surfaces of parts is carried out not by the mechanical department, but by the assembly section of the workshop. The reason for this is that grinding operations, as a rule, are interspersed with metalworking operations, and sometimes carried out by the same toolmakers. The hardened surfaces of device parts are ground on machines, with mechanized tools or manually.
Grinding is carried out with abrasive wheels, heads and bars. Manual grinding with stones is carried out if the surface of the part cannot be processed on a machine. Abrasive bars are used for it various forms and sizes (GOST 2456-52), made from both artificial and natural abrasive materials. It is known that during manual grinding the cutting speed (the speed of movement of the block) is many times lower than the cutting speed when grinding on machines or mechanized tools. In this regard, abrasive bars are selected with greater hardness than grinding wheels. Manual grinding, as a rule, is carried out first with coarse-grained and hard stones, and then with fine-grained and softer stones.
During manual grinding, the surfaces of the bars quickly wear out, become greasy or lose their shape. To restore the shape and performance of the bars, they are periodically straightened on special plates coated with grinding powders. When straightening, the block is placed on the surface of the slab and moved in different directions with some pressure. After several movements along the surface of the slab, the plane of the bar becomes geometrically correct, and its edges become sharp and suitable for further work.
Abrasive stones are used to grind the shaped surfaces of copiers, installations and other parts, as well as the supporting surfaces of assembled devices. Methods for obtaining shaped surfaces, precise planes and angles are similar to the techniques described earlier. However, due to the fact that the accuracy of these surfaces is coarser than the equivalent surfaces of the measuring tool, in the production of devices they rarely resort to pattern finishing, and are more often limited to polishing the surfaces with abrasive sandpaper after mechanical or manual grinding.
The largest volume of preparatory metalworking operations falls on the metalworking of the device body. As stated earlier, the base and base planes of the body are machined before it is sent for assembly. At the assembly site, these surfaces are again inspected, their correctness is checked and damage is repaired. The test is carried out “for paint” using a control plate. The main and technological bases of the building are subjected to the same check.
The accuracy of the device requires a reliable connection between the housing and the components installed on it. Therefore, their connecting surfaces are carefully processed within the range of VV 6 - WV 8 by grinding or scraping. In addition to the necessary cleanliness of the surface, these planes are required to be strictly parallel and perpendicular to the base and bases of the body.
pereosnastka.ru
Main types of locksmith operations.
Production Main types of metalworking operations.
Marking.
Mechanic's workplace.
Topic 25. Basics of plumbing.
1. Locksmith work - ϶ᴛᴏ manual processing of materials, fitting of parts, assembly and repair of various mechanisms and machines.
A workplace is a part of the production area with all the equipment, tools and materials located on it that are used by a worker or a team of workers to complete a production task.
The workplace must occupy the area necessary for the rational placement of equipment and the free movement of the mechanic during work. The distance from the workbench and shelving to the mechanic should be such that he can use predominantly hand movements and, if possible, avoid turning and bending the body. The workplace should have good individual lighting.
A workbench (Fig. 36) is the main equipment of the workplace. It is a stable metal or wooden table, the lid (tabletop) of which is made from boards 50...60 mm thick of hardwood and covered with sheet iron. Single-seat workbenches are the most convenient and common, since on multi-seat workbenches, when several people work simultaneously, the quality of precision work is reduced.
Rice. 36 Single bench:
1 – frame; 2 – tabletop; 3 – vice; 4 – protective screen; 5 – tablet for drawings; 6 – lamp; 7 – shelf for tools; 8 – tablet for working tools; 9 – boxes; 10 – shelves; 11 – seat
The tools necessary to complete the task are placed on the workbench. The drawings are placed on a tablet, and the measuring instruments are placed on the shelves.
Under the workbench tabletop there are drawers, divided into a number of cells for storing tools and documentation.
To secure the workpieces, a vice is installed on the workbench. Considering the dependence on the nature of the work, parallel, chair and hand vices are used. The most widely used are parallel rotary and fixed vices, in which the jaws remain parallel when opened. The rotating part of the vice is connected to the base with a center bolt, around which it can be rotated to any angle and secured in the required position using a handle. To increase the service life of the vice, steel overhead jaws are attached to the working parts of the jaws. Chair vices are rarely used, only for work involving impact loads (for chopping, riveting, etc.). When processing small parts, a hand vice is used.
The choice of the height of the vice according to the height of the worker and the rational placement of the tool on the workbench contribute to better formation skills, increase productivity and reduce fatigue.
When choosing the height of the vice installation, the left hand bent at the elbow is placed on the jaws of the vice so that the ends of the straightened fingers of the hand touch the chin. Tools and devices are placed so that they can be conveniently taken with the appropriate hand: what is taken with the right hand is held on the right, what is taken with the left is held on the left.
A protective screen made of metal mesh or durable plexiglass is installed on the workbench to contain pieces of metal flying off during chopping.
Blanks, finished parts and fixtures are placed on racks installed in the area allocated for them.
2. Marking is the operation of applying lines (scores) to the workpiece, defining (according to the drawing) the contours of the part and the places to be processed. Markings are used for individual and small-scale production.
Markings are carried out on marking plates cast from gray cast iron, aged and precisely machined.
Lines (marks) for planar markings are applied with a scriber, for spatial markings - with a scriber fixed in the clamp of the planer. Scribblers are made from steel grades U10 and U12, their working ends are hardened and sharpened.
The center punch is designed for making recesses (cores) on pre-marked lines. It is made from steel grades U7, U7A, U8 and U8A.
The marking compass is used for drawing circles, dividing angles and applying linear dimensions to the workpiece.
3. Main types of locksmith operations.
Chopping is a metalworking operation in which excess layers of metal are removed from a workpiece using a cutting and impact tool, grooves and grooves are cut out, or the workpiece is divided into parts. The cutting tools are a chisel and a crosspiece, and the impact tool is a hammer.
Cutting is the operation of separating metals and other materials into parts. Taking into account the dependence on the shape and size of the workpieces, cutting is carried out with a hand hacksaw, hand or lever scissors.
A hand hacksaw consists of a steel solid or sliding frame and a hacksaw blade, which is inserted into the slots of the heads and secured with pins. A handle is attached to the shank of the fixed head. A movable head with a screw and a wing nut serves to tension the hacksaw blade. The cutting part of a hacksaw is a hacksaw blade (a narrow and thin plate with teeth on one of the ribs), made of steel grades U10A, 9ХС, Р9, Р18 and hardened. Use hacksaw blades with a length (distance between holes) of 250-300 mm. The teeth of the blade are spread (bent) so that the width of the cut is slightly larger than the thickness of the blade.
Metal straightening is an operation in which unevenness, dents, curvature, warping, waviness and other defects in materials, workpieces and parts are eliminated. Editing in most cases is a preparatory operation. Straightening has the same purpose as straightening, but defects are corrected in hardened parts.
Bending is widely used to give workpieces a certain shape in the manufacture of parts. For straightening and bending manually, straightening plates, straightening headstocks, anvils, vices, mandrels, sledgehammers, metal and wooden hammers (mallets) and special devices are used.
Riveting is a metalworking operation of connecting two or more parts with rivets. Riveted connections are permanent and are used in the manufacture of various metal structures.
Riveting is performed in a cold or hot (if the rivet diameter is more than 10 mm) state. The advantage of hot riveting is that the rod better fills the holes in the parts being joined, and when cooled, the rivet tightens them better. When riveting in a hot state, the diameter of the rivet should be 0.5...1 mm smaller than the hole, and in a cold state - 0.1 mm.
Manual riveting is performed with a hammer, its weight is selected depending on the diameter of the rivet, for example, for rivets with a diameter of 3...3.5 mm, a hammer weighing 200 ᴦ is required.
Filing is a metalworking operation in which a layer of metal is cut off from the surface of a part with files to obtain the required shape, size and surface roughness, to fit parts during assembly and prepare edges for welding.
Files are steel (steel grades U13, U13A; ШХ13 and 13Х) hardened bars of various profiles with teeth cut on the working surfaces. The file teeth, which have a cross-sectional shape of a sharpened wedge, cut off layers of metal in the form of shavings (sawdust) from the workpiece.
Scraping is usually called the operation of scraping thin layers of metal from the surface of a part with a cutting tool - a scraper. This is the final processing of precision surfaces (guide frames of machine tools, control plates, plain bearings, etc.) to ensure a tight fit. The scrapers are made from steels U10 and U12A, their cutting ends are hardened without tempering to a hardness of HRC 64...66.
Lapping and finishing are operations of surface treatment with especially fine-grained abrasive materials using laps.
These operations achieve not only the required shape, but also the highest accuracy (5...6th quality), as well as the lowest surface roughness (up to 0.05 microns).
Fitting and assembly work - ϶ᴛᴏ installation and dismantling work performed during the assembly and repair of machines. The various connections of parts made during machine assembly are divided into two basic types: movable and fixed. When performing plumbing and assembly work, a variety of tools and devices are used: wrenches (simple, socket, sliding, etc.), screwdrivers, drifts, pullers, devices for pressing and pressing.
Marking.
Mechanic's workplace.
Subject. Basics of metalworking.
(self-study)
Questions:
1. Locksmith work – this is manual processing of materials, fitting of parts, assembly and repair of various mechanisms and machines.
Workplace refers to a part of the production area with all the equipment, tools and materials located on it that are used by a worker or a team of workers to complete a production task.
The workplace must occupy the area necessary for the rational placement of equipment and the free movement of the mechanic during work. The distance from the workbench and shelving to the mechanic should be such that he can use predominantly hand movements and, if possible, avoid turning and bending the body. The workplace should have good individual lighting.
Mechanic's workbench(Fig. 48) – the main equipment of the workplace. It is a stable metal or wooden table, the lid (tabletop) of which is made from boards 50...60 mm thick of hard wood and covered with sheet iron. Single-seat workbenches are the most convenient and common, since on multi-seat workbenches, when several people work simultaneously, the quality of precision work is reduced.
Rice. 48 Single bench:
1 – frame; 2 – table top; 3 – vice; 4 – protective screen; 5 – tablet for drawings; 6 – lamp; 7 – shelf for tools; 8 – tablet for working tools; 9 – boxes; 10 – shelves; 11 – seat
The tools necessary to complete the task are placed on the workbench. The drawings are placed on a tablet, and the measuring instruments are placed on the shelves.
Under the workbench tabletop there are drawers, divided into a number of cells for storing tools and documentation.
To secure the workpieces, a vice is installed on the workbench. Depending on the nature of the work, parallel, chair and hand vices are used. The most widely used are parallel rotary and fixed vices, in which the jaws remain parallel when opened. The rotating part of the vice is connected to the base with a center bolt, around which it can be rotated to any angle and secured in the required position using a handle. To increase the service life of the vice, steel overhead jaws are attached to the working parts of the jaws. Chair vices are rarely used, only for work involving impact loads (for chopping, riveting, etc.). When processing small parts, a hand vice is used.
Selecting the height of the vice according to the height of the worker and rational placement of the tool on the workbench contribute to better development of skills, increased productivity and reduced fatigue.
When choosing the height for installing the vice, with your left hand bent at the elbow, place the jaws of the vice so that the ends of the straightened fingers of the hand touch the chin. Tools and devices are placed so that they can be conveniently taken with the appropriate hand: what is taken with the right hand is held on the right, what is taken with the left is held on the left.
A protective screen made of metal mesh or durable plexiglass is installed on the workbench to contain pieces of metal flying off during chopping.
Blanks, finished parts and fixtures are placed on racks installed in the area allocated for them.
2. Marking - the operation of applying lines (scores) to the workpiece, defining (according to the drawing) the contours of the part and the places to be processed. Marking is used for individual and small-scale production.
Markings are carried out on marking plates cast from gray cast iron, aged and precisely machined.
Lines (marks) for planar markings are applied with a scriber, for spatial markings - with a scriber fixed in the clamp of the planer. Scribblers They are made from steel grades U10 and U12, their working ends are hardened and sharpened.
Kerner designed for making indentations (cores) on pre-marked lines. It is made from steel grades U7, U7A, U8 and U8A.
Marking compass used for drawing circles, dividing angles and applying linear dimensions to the workpiece.
3. Main types of locksmith operations.
Chopping– a metalworking operation, during which excess layers of metal are removed from the workpiece using cutting and impact tools, grooves and grooves are cut out, or the workpiece is divided into parts. The cutting tools are a chisel and a crosspiece, and the impact tool is a hammer.
Chisel They chop the metal and cut off the burrs. It has a working middle and shock parts. The working part of the chisel is wedge-shaped with a cutting part sharpened depending on the hardness of the metal being processed at a certain angle. The chisel is held by the middle part when chopping; the striking part (head) tapers upward and is rounded to center the blow.
Kreutzmeissel grooves and narrow grooves are cut out, and to cut profile grooves, special cross-cutters are used - “groovers”, which differ in the shape of the cutting edge.
Chisels, cross-cutters and groovers are made from steel U7, U7A, U8 and U8A. Their working and striking parts are hardened and tempered.
Locksmith's hammers have a square or round striking part - the striker. The end of the hammer opposite the striker, which has the shape of a rounded wedge, is called the toe. It is used for riveting, straightening, etc.
Hammers are made from steel grades 50, 50X, U7 and U8. The working parts of the hammer (head and toe) are hardened and tempered.
cutting is the operation of separating metals and other materials into parts. Depending on the shape and size of the workpieces, cutting is carried out with a hand hacksaw, hand or lever scissors.
Hand saw consists of a steel solid or sliding frame and a hacksaw blade, which is inserted into the slots of the heads and secured with pins. A handle is attached to the shank of the fixed head. A movable head with a screw and a wing nut serves to tension the hacksaw blade. The cutting part of a hacksaw is a hacksaw blade (a narrow and thin plate with teeth on one of the ribs), made of steel grades U10A, 9ХС, Р9, Р18 and hardened. Use hacksaw blades with a length (distance between holes) of 250-300 mm. The teeth of the blade are spread (bent) so that the width of the cut is slightly larger than the thickness of the blade.
Metal straightening– an operation in which unevenness, dents, curvature, warping, waviness and other defects in materials, workpieces and parts are eliminated. Editing in most cases is a preparatory operation. Straightening has the same purpose as straightening, but defects are corrected in hardened parts.
bending widely used to give workpieces a certain shape in the manufacture of parts. For straightening and bending manually, straightening plates, straightening headstocks, anvils, vices, mandrels, sledgehammers, metal and wooden hammers (mallets) and special devices are used.
Riveting- a metalworking operation of connecting two or more parts with rivets. Riveted connections are permanent and are used in the manufacture of various metal structures.
Rivets are cylindrical metal rods with pre-set heads. They are made from carbon steels, alloy steels 09G2 and Kh18N9T, non-ferrous metals and alloys MZ, L62, AD1 and D18P. Several types of rivets are used: with a semicircular high or low head, with a flat head, with a countersunk and semi-countersunk head, explosive, two-chamber. The most commonly used rivets are those with semicircular and countersunk heads. The second (closing) head of the rivet is planted during riveting.
Riveting is performed in a cold or hot (if the rivet diameter is more than 10 mm) state. The advantage of hot riveting is that the rod better fills the holes in the parts being joined, and when cooled, the rivet tightens them better. When riveting in a hot state, the diameter of the rivet should be 0.5...1 mm smaller than the hole, and in a cold state - 0.1 mm.
Manual riveting is done with a hammer; its weight is selected depending on the diameter of the rivet, for example, for rivets with a diameter of 3...3.5 mm, a hammer weighing 200 g is required.
Filing– a metalworking operation in which a layer of metal is cut off from the surface of a part with files to obtain the required shape, size and surface roughness, to fit parts during assembly and prepare edges for welding.
Files are steel (steel grades U13, U13A; ШХ13 and 13Х) hardened bars of various profiles with teeth cut on the working surfaces. The file teeth, which have a cross-sectional shape of a sharpened wedge, cut off layers of metal in the form of shavings (sawdust) from the workpiece.
Files manufactured with single and double (cross) notches. According to their purpose, files are divided into groups: general purpose, special purpose, needle files, rasps, machine files. Depending on the number of notches per 1 cm of length, files are divided into the following numbers: 0 and 1 - quarrel, 2 and 3 - personal, 4 and 5 - velvet. Brushed files are used for rough filing, when it is necessary to remove a layer of metal more than 0.3 mm; the accuracy of their processing is low. For finishing filing with an accuracy of 0.02 and 0.05 mm, personal files are used; the thickness of the metal layer they remove is no higher than 0.02 and 0.06 mm. Velvet files are designed for finishing parts with an accuracy of 0.01...0.005 mm, the thickness of the metal layer they remove is 0.01...0.03 mm.
Files with a notch in the form of individual (point) teeth are called rasps. They are used for filing viscous and soft materials (babbitt, wood, etc.).
For processing small surfaces and finishing work, needle files are used. Files are produced in lengths of 100, 125, 150, 200, 250, 300, 350 and 400 mm. According to the cross-sectional shape, files are produced in eight types: flat
(sharp-nosed and blunt-nosed), square, round, semicircular, triangular, rhombic and hacksaw.
In the process of making and processing holes, drills are used, countersinks, countersinks and reamers.
During metalworking, in some cases, holes are drilled and machined manually. In this case, the tool is rotated using hand, electric and pneumatic drills, as well as using ratchets. When manual countersinking and reaming, the tool is secured in a driver and rotated, and the workpiece (just as when drilling) is clamped in a vice or other devices. It should be remembered that working with a dull or improperly sharpened tool on faulty equipment and devices causes tool breakage and defective parts.
Threaded connection– a reliable type of fastening of machine parts. It allows easy assembly, adjustment, and disassembly.
A helical groove cut on the outer or inner cylindrical surface forms an external or internal thread, respectively. The thread profile is the cross-section of its turn with a plane passing through the axis of the cylinder on which the thread is cut. Thread (twist) called the part of the thread formed during one full revolution of the profile. Profile angle thread is the angle enclosed between the sides of the thread profile. Profile cavity– a section connecting the sides of the groove. Thread pitch– the distance between two points of the same name on adjacent turns, measured parallel to the thread axis.
According to the thread profile, there are cylindrical triangular, conical triangular, rectangular, trapezoidal, thrust and round.
There are three common triangular thread systems in mechanical engineering: metric, inch and pipe. Metric thread has a profile angle of 60°, characterized by a pitch and diameter expressed in the metric system of measures - millimeters. Inch thread has a profile angle of 55°, the outer diameter is measured in inches (1" is equal to 25.4 mm), the pitch is characterized by the number of threads per 1", it is rarely used. Pipe thread has a profile inch thread and is characterized by the number of threads 1", used for connecting pipes.
Tools for cutting threads are taps And dies. They are made from steels U10A, U11A, U12A, 9ХС and Р18.
To cut threads in holes, use a set of two or three taps with different diameters of the working part (rough, medium and finishing). To distinguish the tap, circular marks are applied to its shank. The finishing tap has three circular marks and is used for finishing thread cutting, as it has a full profile of the cutting part.
Several types of dies are used for cutting external threads: round, square, hexagonal and sliding prismatic.
The diameter of the drill to obtain a hole for the thread is determined from tables or (with sufficient accuracy) by subtracting its pitch from the diameter of the thread. The diameter of the rod should be equal to the outer diameter of the thread being cut, but usually it is taken 0.3...0.4 mm less to obtain good thread quality.
Emulsion, kerosene, and machine oil are used as lubricants.
Scraping is the operation of scraping thin layers of metal from the surface of a part with a cutting tool - scraper. This is the final processing of precision surfaces (guide frames of machine tools, control plates, plain bearings, etc.) to ensure a tight fit. The scrapers are made from steels U10 and U12A, their cutting ends are hardened without tempering to a hardness of HRC 64...66.
The scrapers are divided: by design (solid and with insert plates); by the number of cutting ends (one-sided and two-sided); according to the shape of the cutting part (flat, tri-, tetrahedral and shaped).
For scraping planes, a flat scraper with a straight or curved cutting edge is used; its cutting part is sharpened for rough processing at an angle of 70...75°, and for finishing - 90°. Internal cylindrical surfaces are processed with a triangular scraper.
The checking tools for scraping are plates, flat and angled rulers, and rollers.
The preparation process and scraping are carried out in the following sequence. The surfaces of the part are cleaned and wiped. A thin layer of paint (soot, glaze and others mixed with machine oil) is applied to the surface plate and the part being treated is carefully placed on the plate. Then the part is moved in a circular motion across the plate and carefully removed. On the surface to be treated, the most prominent areas are slightly colored. During the scraping process, the metal is gradually scraped off from the painted areas, moving the scraper with light pressure forward, each time in different directions so that the strokes intersect at an angle of 90°. During rough scraping, the working stroke of the tool is 10...15 mm, and during finishing - 4...5 mm.
To check the accuracy of scraping the planes, apply a frame measuring 25x25 mm to them in several places and count the number of spots in the area limited by the frame. Scraping is completed with the following number of spots: rough - 8...10, semi-finish - 12, fine - 15, fine - 20, fine - 25. In addition, the surface should have a fine and uniform stroke, without deep scraper marks. The accuracy of scraping curved surfaces is checked using a template - a mesh.
Lapping and finishing– operations of surface treatment with especially fine-grained abrasive materials using laps.
These operations achieve not only the required shape, but also the highest accuracy (5...6th quality), as well as the lowest surface roughness (up to 0.05 microns).
To prepare the lapping mixture, finely ground abrasive materials are used: electrocorundum, silicon carbide, boron carbide, synthetic diamonds, chromium oxide, etc. Machine oil, kerosene, stearin and petroleum jelly are used as a binding liquid.
When lapping, GOI pastes are widely used, which contain, in addition to abrasives and binders, surfactants, as well as diamond pastes.
The lap material must be softer than the surface of the material being ground. It is usually made from gray cast iron, bronze, copper and wood. The shape and dimensions of the lap must be very accurate, since they copy the surface being processed.
To grind the planes, lapping plates are used, along which the parts are evenly moved in a circular motion with slight pressure. By lapping on plates, high precision processing is achieved.
Internal conical surfaces are lapped with conical lapping plugs, and external ones - in special lapping surfaces with a conical hole.
Grinding is carried out until the surface becomes matte or mirror-like. Quality is checked with paint, which should spread evenly over the entire surface.
Fitting and assembly work– these are installation and dismantling work performed during the assembly and repair of machines. The various connections of parts made during machine assembly are divided into two main types: movable and fixed. When performing plumbing and assembly work, a variety of tools and devices are used: wrenches (simple, socket, sliding, etc.), screwdrivers, drifts, pullers, devices for pressing and pressing.
Greetings friends! Let's discuss what types of locksmith operations exist. Let’s not forget to understand in detail what they are intended for and how to perform them correctly in order to prevent mistakes and injuries.
Locksmith operations. Who does it and what is it?
Locksmith operations- this is a set of actions of a toolmaker or repairman performed with a special tool in a certain sequence. During these operations, the metal is subjected to manual processing. Seven sweats can come off while you complete these works. This includes various adjustments and adjustments of parts, repair of mechanisms and components.
By the way, I was inspired to write this post by the unexpected (for me) popularity of a post that I recently published on my blog. I wrote it from my own experience working at a factory. Glad you liked it.
Types of locksmith operations. Purpose and application.
To get started, look at this one video lesson about the main types of locksmith operations:
There are actually plenty of such jobs, and we will talk about each operation separately. For some points, we will watch video materials to reinforce the information.
1. Metal cutting.
When chopping metal, just hold it in a vice and pick up a tool called a chisel. Please note that before performing this plumbing operation, you must at least theoretically understand what you are doing. From the outside it looks simple and easy, but in fact there are a number of tricks.
For example, the chisel angle should be approximately 35 degrees. If more or less work will be done very reluctantly. There is no need to grab the chisel with a death grip. Hold it with 3-4 fingers with a little force. Well, how to hit it with a hammer is up to you. Strike rhythmically and don't knock your fingers off.
2. Marking the part.
The main types of locksmith operations include: marking. The mechanic takes tools such as a square, a pattern, a hammer, a chisel, and even a special marking compass. He selects devices depending on the complexity of the operation being performed. Perhaps the most popular is the metal scriber; we will devote a separate post to it. Stay tuned.
Placing a sheet of metal in front of him, the mechanic begins to create. To begin with, he uses a regular pencil to make preliminary markings. When the design of the future part is drawn, we put the pencil aside. Next, a rough tool comes into play, which literally rips out (scratches) the contour of the workpiece. When all the lines are drawn, it is very easy to cut, punch out or extrude the required part or workpiece along them.
3. Metal cutting.
Then I remembered my school days, and my daughter probably studied at kindergarten. When you have made the markings, take the scissors and feel free to start cutting. To tell the truth, the process is not very pleasant. From the outside it seems even cool to cut out figures from metal. In life, when metal scissors begin to dig into your fingers and cause unbearable pain, it’s no longer a joke. Out of habit, this type of plumbing operation causes great discomfort to the hands.
The more often you perform these steps, the painless this process will be. If the metal is thick or strong enough, scissors won't cut it. Here you will have to resort to hydraulic shears or a guillotine. The guillotine is not the one that has been used since 1791 for cutting off heads (which was invented by Joseph Guillotin), but a machine for cutting off sheets of metal. Watch the video on how to use metal scissors.
4. Metal straightening.
We see in the figure two main options for straightening metal. The two top pictures show an option when shock loading is necessary to correct crooked metal convolutions. For this you will need special hammers. The head of such a tool is made of wood, brass, duralumin, plastic with a metal core, etc. The main condition for such a tool is that it must be softer than the workpiece you are going to edit.
The second view shows how a piece of metal is straightened using a special device (to increase torque) and a regular bench vice. Special machines and devices are used for straightening bars. If you are interested in this topic, read more on the Internet, or better yet, pick up a book on plumbing. And we continue study the main types of locksmith operations.
5. Riveting. Creation of permanent connections.
I'll tell you right away. The connection of two sheets of metal with rivets is called a “rivet seam” by experienced mechanics. The picture on the left shows stretch And support.
Shown on the right swage. The whole riveting process looks something like this.
Riveting process. Step-by-step instruction.
Today there are already a lot of devices and automated machines for making rivet seams. But the principle of operation is the same for all of them. The classic is immortal..
Take a file in your hands and let's go. That's what our plumbing teacher told me. But during the filing process, it is important not only to remove chips from the part, but also to maintain the size according to the sketch or drawing. Perform this metalworking operation extremely carefully - there is a high probability of injury. When the work is completed, it is necessary to check the compliance of the part with the drawing parameters.
Inspection of the part after filing.
Everything is much simpler here. Attach a test square (or template) to the part and look at the light. There should be no gaps, or they will be minimal if allowed. Templates can be varied depending on the part.
7. Scraping or adjusting surfaces.
Scraping is a metalworking operation for particularly precise fitting of surfaces. Even today, this seemingly outdated method is relevant and mechanization is not acceptable. The process is as follows. Red lead paint is applied to the surface and the mating part is attached. All irregularities that remain as a result of such an application are eliminated using a tool called a scraper.
Let me tell you, Shabreni is not for the faint of heart. In terms of precision, it can be compared to jewelry. Such operations are used in the manufacture of guides production equipment, sliding bearings of machine carriages, etc. When scraping, it is possible to achieve a roughness of up to 0.32 Ra.
Types of locksmith operations. Conclusion.
And I say goodbye to you! ALL THE GOOD TO YOU!
Andrey was with you!
PLITTERING
Plumbing
Plumbing
Locksmith
Installation operations include
Professional team
Locksmith's workplace
Locksmith workshop
Locksmith workshop - this is a room specially designed for metalwork and equipped with necessary equipment, devices, tools and technical equipment. The metalworking workshop should be equipped with workbenches (according to the number of workers), tools, a straightening plate, a lapping plate, a mechanical plate, lever shears, a drilling machine, a hand drilling tool, a sharpening machine, an electric portable grinding machine, a screw press, jacks, a forge with an anvil. In large workshops, turning, planing, sometimes milling and grinding machines, as well as an electric welding machine, equipment for gas welding, oven for heat treatment, bath for cooling parts subjected to heat treatment, auxiliary equipment. The acetylene generator is placed in a separate room, since its improper operation can lead to an explosion with serious consequences. The staff of a locksmith workshop usually consists of a foreman, mechanics and apprentices. The nature of the work is the provision of services and repair work, less often - the production of products of a certain profile.
Mechanical section of the workshop
Metalworking area at an industrial enterprise is an independent production unit of the workshop, which occupies a significant area and is equipped with workbenches, tools, main and auxiliary equipment. The staff of the site consists of several dozen or even several hundred people. Depending on the size of the enterprise, independent assembly and metalwork shops can be organized, which may include production units(instrument storeroom, storeroom of materials and components, control department and a number of other production and auxiliary departments). Separate machine parts and devices manufactured in other areas are delivered to the metalworking and assembly area. From these parts, site workers assemble assembly units, kits or assemblies from which machines are assembled. The products of the metalworking and assembly section of the workshop can be presented in the form of parts. However, the site, as a rule, does not provide other maintenance services for the workshop or plant. The metalworking section of the workshop should be equipped with workbenches equipped with vices, manual and mechanical drilling machines, tool sharpening machines, mechanical saws, lever shears, plates for straightening and lapping, marking plate, portable electric grinding machines, machines and tools for soldering, means of mechanization of lifting and transport work, racks and containers for parts, waste containers, tool storage. Depending on the production needs and the type of products manufactured by the enterprise, the metalworking area can be equipped with pneumatic chisels and hammers, presses for stamping and straightening, coating equipment, jacks, compressors, machines, cranes, equipment for gas and electric welding.
1.6. Occupational Health, Safety and Health
Work is safe if it is performed under conditions that do not threaten the life and health of workers. At industrial enterprises, all responsibility for occupational health and safety lies with the heads of the enterprise, workshop, section (director, workshop manager, foreman). Each enterprise must have a labor safety department that monitors compliance with safe work conditions and implements measures to improve these conditions.
Workers are required to comply with the requirements of labor protection instructions. Before starting work, the employee must undergo occupational safety training.
Occupational health is a branch of preventive medicine that studies the effects on the human body labor process and factors of the production environment in order to scientific justification standards and means of prevention occupational diseases and other adverse consequences of exposure to working conditions on workers.
Worker starting work must be healthy and neatly dressed. Hair must be tucked under a headdress (beret, headscarf). Locksmith rooms must have sufficient lighting in accordance with current regulations. There are natural (daylight) and artificial (electric) lighting. Electric lighting can be general and local. The floor in the metalworking room should be made of end blocks, wooden beams or asphalt mixtures. Avoid contaminating the floor with oil or grease as this may cause an accident. To avoid accidents at the enterprise and in the workplace, it is necessary to comply with safety requirements. All moving and rotating parts of machines, equipment and tools must have protective screens. Machinery and equipment must be properly grounded. Electricity sources must comply with current technical requirements. Where fuses are installed, special protective equipment must be used. Maintenance and repair of equipment and accessories must be carried out in accordance with the operating and repair instructions. The tool must be in good working order.
Information (for example, “Water for drinking”, “Locker room”, “Toilets”, etc.), warnings (for example, “Attention - train”, “Stop! High voltage”, etc.) and prohibitions should be posted in prominent places (for example, “No smoking!”, “Grinding without glasses is prohibited,” etc.) signs. Steel and hemp ropes of various lifting and transport equipment and accessories, and seat belts must be systematically tested for strength. Fire and access routes, passages for pedestrians (both on the territory of the enterprise and indoors) must be safe for traffic. Damaged ladders should not be used. Open channels and manholes should be well marked and fenced. At the enterprise and at the workplace, the employee’s thoughts should be focused on the work assigned to him, which must be completed quickly and efficiently. Violations of labor and production discipline and alcohol consumption are unacceptable at work.
Upon completion of work you should put in order workplace, put tools and equipment in a tool box, wash your hands and face with warm water and soap, or take a shower. Overalls should be stored in a closet specially designed for this purpose. Each site or workshop must be equipped with a first aid kit (first aid station). The first aid kit should contain sterile bandages, cotton wool, disinfectants, plaster, bandages, tourniquets, sterile bags, triangular scarves, splints and stretchers, valerian drops, painkillers, cough tablets, ammonia, iodine, pure alcohol, baking soda. At an enterprise or workshop, teams (teams) of rescuers or sanitary instructors are formed from among specially trained workers. A rescuer or sanitary instructor provides first aid to the victim in case of accidents, calls emergency assistance, transports the victim home, to a clinic or hospital, and does not leave the victim until he is provided with the necessary medical care.
Employees of enterprises and metalworking shops who work with metal most often experience the following work-related injuries: cuts or damage to the surface of tissues with a sharp instrument, eye damage from metal fragments or shavings, burns, electric shock.
Burn – this is damage to body tissues that are in direct contact with a hot object, steam, hot liquid, electric current, or acid. There are three degrees of burns: first degree - redness of the skin, second - the appearance of blisters, third - necrosis and charring of tissue. For minor burns (first degree), first aid is provided using cleansing agents. Do not apply a compress with oil or any ointment as this may lead to further irritation or infection, which will require long-term treatment. The burned area should be bandaged with a sterile bandage. A victim with first, second or third degree burns should be immediately sent to the hospital.
In case of electric shock the victim is first of all freed from the source of the lesion (to do this, it is necessary to break the connection, turn off the voltage or drag the victim away from the site of the lesion, while wearing insulating shoes and gloves) and lay him on a dry surface (boards, doors, blanket, clothes), unfasten the squeezing throat, chest and stomach clothes. Clenched teeth need to be unclenched, the tongue should be stretched out (preferably with a handkerchief) and a wooden object should be placed in the mouth to prevent the mouth from closing spontaneously. After this, artificial respiration begins (15–18 shoulder movements or breaths per minute). Artificial respiration should be interrupted only on the recommendation of a doctor or if the victim begins to breathe on his own. The most effective method of artificial respiration is the “mouth to mouth” and “mouth to nose” methods.
In the event of a fire you should stop work, turn off electrical installations, equipment, ventilation, call the fire department, inform the management of the organization and begin extinguishing the fire using available fire extinguishing means. Safety precautions when performing individual species works are briefly reviewed in the relevant sections.
Technological process
Technological process - this is part production process directly related to changes in shape, size or physical properties materials or semi-finished products until the product of the required configuration and quality is obtained. The technological process is also defined as a part of the production process that contains actions to change and subsequently determine the state of the item of production.
The technological process consists of operations.
Operation - this is a part of the technological process performed by a mechanic at one workplace with or without the use of mechanized or manual tools, mechanisms, devices when processing one part. Examples of operations: making a groove for lubrication on a sliding bearing, cutting a screw surface on a rod, cutting a thread in a hole, etc. The elements of a technological operation are installation, technological transition, auxiliary transition, working stroke, auxiliary stroke, position.
Installation - part of a technological operation performed with constant fastening of the workpiece or assembled assembly unit. For example, drilling one or more holes of different diameters in a part while securing the part unchanged, cutting threads on a rod.
Technological transition - a completed part of an operation, characterized by the constancy of the tool used and the surfaces formed during processing or connected during assembly. For example, drilling a part with a drill of the same diameter or connecting a bushing to a shaft.
Auxiliary transition – part of the operation without changing the geometry of the surface being processed or the position of the assembled parts, necessary to perform a technological transition (installation of a workpiece, changing tools, etc.).
Working stroke – a completed part of the operation associated with a single movement of the tool relative to the workpiece, necessary to change the geometry of the part. The auxiliary stroke is not associated with a change in the geometry of the part, but is necessary for the implementation of the working stroke.
Position - this is a fixed position occupied by a fixed workpiece or assembled assembly unit together with a device relative to a tool or a stationary piece of equipment to perform a certain part of the operation.
A technological process map is a technological document containing a description of the process of manufacturing, assembly or repair of a product (including control and movement) for all operations of one type of work performed in one workshop, in technological sequence, indicating data on technological equipment, material and labor standards. It also determines the place of work, the type and dimensions of the material, the main processing surfaces of the part and its installation, working tools and devices, as well as the duration of each operation. The technological process is developed on the basis of a drawing, which for mass and large-scale production must be executed in great detail. In case of single production, only a route technological process is often given, listing the operations required for processing or assembly. The time required to manufacture a product with a single and small-scale production, is established approximately on the basis of timing or accepted standards, and in large-scale and mass production - on the basis of design and technical standards.
Based is called giving the workpiece or product the required position relative to the selected coordinate system.
Base - this is a surface, a combination of surfaces, an axis or a point belonging to a workpiece or product and used for basing. Based on their purpose, bases are divided into design, main, auxiliary, technological and measuring. The design basis is used to determine the position of a part or assembly unit in a product.
Main base is a design basis that belongs to a given part or assembly unit and is used to determine its position in the product. For example, the main bases of a shaft assembled with bearings are its support journals and a thrust collar or flange.
Auxiliary base - this is a design base that belongs to a given part or assembly unit and is used to determine the position of the product attached to it. For example, when connecting a shaft to a flanged bushing, the auxiliary base may be the shaft diameter, its shoulder and key.
Technological base is a surface, a combination of surfaces or an axis used to determine the position of a workpiece or product during the manufacturing or repair process. For example, the plane of the base of the part and two base holes.
Measuring base used to determine the relative position of a workpiece or product and measuring instruments.
Marking
Marking is the operation of applying lines and dots to a workpiece intended for processing. Lines and dots indicate processing boundaries.
There are two types of markup: flat and spatial. Marking is called flat when lines and points are applied to a plane, spatial – when marking lines and points are applied to a geometric body of any configuration.
Spatial marking can be done on a marking plate using a marking box, prisms and squares. When marking in space, prisms are used to rotate the workpiece being marked. For flat and spatial marking, a drawing of the part and a workpiece for it, a marking plate, a marking tool and universal marking devices, a measuring tool and auxiliary materials are required.
Marking tools include: scriber (with one point, with a ring, double-sided with a curved end), marker (several types), marking compass, center punches (regular, automatic for stencil, for circle), calipers with a conical mandrel, hammer, center compass, rectangle, marker with prism.
Marking devices include: marking plate, marking box, marking squares and bars, stand, thicknesser with scriber, thicknesser with moving scale, centering device, dividing head and universal marking grip, rotating magnetic plate, double clamps, adjustable wedges, prisms, screw supports.
Measuring tools for marking are: a ruler with divisions, a thickness gauge, a thickness gauge with a moving scale, a caliper, a square, a protractor, a caliper, a level, a control ruler for surfaces, a feeler gauge and standard tiles.
To auxiliary materials for marking include: chalk, white paint (a mixture of chalk diluted in water with linseed oil and the addition of a composition that prevents the oil from drying out), red paint (a mixture of shellac with alcohol with the addition of dye), lubricant, washing and etching materials, wooden blocks and slats, small tin utensils for paints and brush.
Simple marking and measuring tools tools used in plumbing work are: a hammer, a scriber, a marker, an ordinary center punch, a square, a compass, a marking plate, a graduated ruler, a vernier caliper and a caliper.
Planar or spatial marking of the part is carried out on the basis of the drawing. Before marking, the workpiece must undergo mandatory preparation, which includes the following operations: cleaning the part from dirt and corrosion (do not do it on a marking plate); degreasing the part (do not do it on a marking plate); inspection of the part in order to detect defects (cracks, cavities, bends); checking overall dimensions and processing allowances; determination of the marking base; covering with white paint the surfaces to be marked and lines and dots applied to them; determination of the axis of symmetry. If a hole is taken as a marking base, then a wooden plug should be inserted into it.
Marking base - this is a specific point, axis of symmetry or plane from which, as a rule, all dimensions on a part are measured.
By capping called the operation of applying small dots-indentations on the surface of a part. They define the centerlines and hole centers required for machining, certain straight or curved lines on the product. Marking is done with the purpose of marking on the part persistent and noticeable marks that define the base, processing boundaries or drilling location. The punching operation is performed using a scriber, a center punch and a hammer.
Markup using a template used in the manufacture of a significant number of identical parts. A template made of tin 0.5–2 mm thick (sometimes stiffened with a corner or wooden strip) is placed on the flat surface of the part and traced along the contour with a scriber. The accuracy of the applied contour on the part depends on the degree of accuracy of the template, the symmetry of the scriber's tip, as well as on the method of advancing the scriber's tip (the tip must move perpendicular to the surface of the part). The template is a mirror image of the configuration of parts, lines and points that must be applied to the surface of the part.
The accuracy of marking (the accuracy of transferring dimensions from the drawing to the part) depends on the degree of accuracy of the marking plate, auxiliary devices (squares and marking boxes), measuring instruments, the tool used to transfer dimensions, on the degree of accuracy of the marking method, as well as on the qualifications of the marker. The marking accuracy is usually from 0.5 to 0.08 mm; when using standard tiles - from 0.05 to 0.02 mm.
When marking, you should handle sharp scribers with care. To protect the worker’s hands before marking, it is necessary to put a cork, wooden or plastic cover on the tip of the scriber.
To install heavy parts on the marking plate, you should use hoists, hoists or cranes. Spilled oil or other liquid on the floor or marker board may cause an accident.
PLITTERING
Practical guide for a mechanic
GENERAL INFORMATION ABOUT FITTING WORKS
Plumbing
Plumbing is a craft that consists of the ability to process metal in a cold state using hand tools (hammer, chisel, file, hacksaw, etc.). The purpose of plumbing is handmade various parts, performing repair and installation work.
Locksmith is a worker who performs cold processing of metals, assembly, installation, dismantling and repair of all kinds of equipment, machines, mechanisms and devices using hand tools, simple tools and equipment (electric and pneumatic tools, simple cutting and drilling machines , welding, bending, pressing, etc.). The processing or assembly process (in relation to plumbing work) consists of individual operations strictly defined by the developed technological process and performed in a given sequence. An operation is understood as a completed part of a technological process performed at one workplace. Individual operations differ in the nature and volume of work performed, the tools, devices and equipment used.
When performing plumbing work, operations are divided into the following types:
Preparatory (related to preparation for work),
Basic technological (related to processing, assembly or repair),
Auxiliary (dismantling and installation).
Preparatory operations include: familiarization with technical and technological documentation, selection of appropriate material, preparation of the workplace and tools necessary to perform the operation.
The main operations are: cutting off the workpiece, cutting, sawing, drilling, reaming, threading, scraping, grinding, lapping and polishing.
Auxiliary operations include: marking, punching, measuring, securing the workpiece in a fixture or bench vice, straightening, bending material, riveting, shading, soldering, gluing, tinning, welding, plastic and heat treatment.
Dismantling operations include all operations associated with disassembling (using hand or power tools) a machine into kits, assemblies and parts.
Installation operations include assembly of parts, assembly units, kits, units and assembly of machines or mechanisms from them. In addition to assembly work, installation operations include monitoring compliance with the main installation dimensions technical documentation and requirements technical control, in some cases – manufacturing and fitting of parts. Installation operations also include the adjustment of assembled assembly units, kits and assemblies, as well as the entire machine as a whole.
1.2. Professional specialization
A specialist in a particular profession is a worker who performs a narrow range of work. Narrow specialization gives the employee the opportunity to better and more accurately know and perform assigned operations.
In the locksmith profession, there is a professional specialization associated with the maintenance and repair of specialized machines, equipment and various types of tools, for example: maintenance and repair of railway equipment, metallurgical equipment, automobile, tractor and agricultural machinery, urban water supply and sewerage systems, etc.
The main difference between a workshop and a specialized locksmith shop is that there is no specialization in a locksmith shop. All operations related to the locksmith profession are performed in it. A locksmith shop in the local industrial, service and repair industry has a limited number of workers performing all possible types of work.
Specialized metalworking areas in factory workshops have a large number of workers of various specialties who perform only metalworking work in accordance with the production and technological process of the workshop.
Professional team is a group of workers of one or more professions and different specialties, which specializes in performing work of a similar nature. For example, locksmith work when repairing vehicles, locksmith work during plumbing and sewerage work, etc. Currently, a combination of professions is being developed in such teams, allowing workers to perform a wider range of work. The following professions can work in repair and specialized workshops: mechanics, blacksmiths, tinsmiths, car repair mechanics, household appliances, electromechanics, welders, boilermakers, embossers, precision machine mechanics, foundry workers, etc. Mechanics of various specialties can work at industrial enterprises: tool maker, pattern maker, scriber, fitter, adjuster, equipment repair mechanic , mechanic for repair of electrical equipment, sanitary equipment, industrial heating networks, etc.
Locksmith's workplace
At the workplace, a mechanic performs operations related to his profession. The workplace is equipped with the equipment necessary to carry out plumbing work. The mechanic's workplace can be located both indoors and outdoors. open area in accordance with the layout of the production facility and the technology of the production process. The area of a mechanic's workplace depends on the nature and volume of work performed. In industrial enterprises, a mechanic's workplace can occupy 4–8 m2, in workshops - at least 2 m2. Mechanic's workplace in indoors, as a rule, permanent. The outdoor workplace can be moved depending on the production environment and climatic conditions.
At the mechanic's workplace there should be a workbench equipped with appropriate devices, primarily a bench vice. The mechanic performs most operations at a bench using a vice.
The workplace of an assembly fitter or equipment repairman can be located at the assembly site. In addition to the main workplace (behind the workbench), the mechanic may have auxiliary workplaces, for example, at the marking, lapping or control plates, at the forge or anvil, at welding machine, drilling machine, mechanical saw, hand press, straightening plate, etc.
Auxiliary workplace becomes the main one if the work is of a special nature, for example, a workplace at a drilling machine, which is serviced by a driller, a workplace at a lapping plate, behind which a lapping mechanic works, a workplace at a welding machine, which is operated by a welder, etc. d.
Locksmith workshop
Despite the rapid development of robotics, manual labor remains in great demand. At the same time, good locksmiths are highly valued. Application area manual labor extensive - from handicraft industries and households to modern manufacturing enterprises equipped with the latest technology. Of course, there are many types. It is not possible to list everything in one article. But to give an idea of the main and most common jobs and give short review tool - possible.
General provisions
This refers to the assembly and repair of all kinds of components, processing of materials (steels and metal alloys) in a variety of sectors of the national economy: mechanical engineering, consumer services population (lock repairs, etc.), service maintenance and car repair. Accordingly, they distinguish different types locksmith works.
A locksmith's workplace can look different. In general, this is a certain area of the workshop (site), equipped with all the necessary equipment and tools. Species can differ dramatically from each other. Therefore, in one case the workplace is a desk in a warm and cozy room, in the other it is a tent without amenities somewhere in the taiga (during the construction and repair of gas and oil pipeline infrastructure).
The most common and universally recognizable tool of a mechanic is the workbench. This is, in fact, a table on which everything is available necessary tools to carry out technological operations assigned to a given workplace. There must also be a device for securing working drawings of products.
As a rule, the tabletop itself is made of hardwood and covered with sheet steel one millimeter thick. It is advisable to equip drawers under the table for storing tools and materials. The absence of a protective metal screen on the workbench is considered gross violation norms and rules of labor protection.
Bench vice
A mandatory attribute of a mechanic's workbench is a vice. After all, without them it is impossible to quickly and efficiently remove a burr after cutting, as well as smooth out sharp corners. Depending on the intended type of metalwork, vices can be manual, chair or parallel. Due to their simplicity of design, ease of use and versatility, parallel (with or without a rotating mechanism) vices are most widely used. When unclenched, the jaws of such a vice remain parallel to each other.
For some types it is necessary to use a vice with a rotating mechanism. This allows you to significantly speed up the execution of a number of technological operations, provides production flexibility and the ability to quickly changeover to produce new products. As a rule, the upper part is rotating and is attached to the base with one large bolt in the center or several on the sides. If necessary, for some types of plumbing work, you can quite quickly turn a rotary vice into an ordinary stationary one. This will significantly increase the rigidity of the device and reduce vibration.
The scope of use of chair vices is very small. It is limited only to work associated with significant cyclic impact impacts on the device.
The height of the workbench and, accordingly, the vice should be selected taking into account the height of the worker. This will significantly increase work efficiency and reduce fatigue. The installation height of the vice is considered optimal if the worker, bending his arm at the elbow, can roll the jaws of the vice with it. In this case, the fingers of the hand should touch the chin.
Types of locksmith work and their purpose
The following classification of plumbing work is generally accepted:
- preparatory,
- processing to size,
- customizable.
As a rule, a locksmith has a certain narrow specialization. And one specialist can quickly and efficiently perform only a certain type of work. There are, of course, some sort of generalist specialists. But these are, as a rule, young workers who have only recently left the walls educational institution and are just learning the basics of the profession. They cannot be trusted with truly complex and responsible work.
The purpose of certain types of work is indicated by their name. Thus, preparatory work is aimed at ensuring preparation for the process, processing to size - influencing the material and workpiece with a tool in order to give it a given shape, fitting - assembling and finishing parts and assemblies.
Preparatory work
This group includes the following types of locksmith work:
- metal marking,
- cutting,
- straightening,
- bending and cutting of steels and alloys.
These operations are initial and are aimed at obtaining a workpiece for further processing or transfer to the heat treatment area.
These works are characterized by low productivity and high labor intensity. Instead of cutting sheet material with a chisel and by hand, almost all industrial enterprises use CNC laser cutting machine program controlled. But in home workshops, when it is necessary to obtain blanks from thin-sheet material, they still use and will obviously continue to use for a very long time this technology. This technique is also used in repair shops and is one of the most common types of plumbing and mechanical work when servicing cars.
The same situation is typical for metal marking: modern plasma, gas and laser cutting machines make it possible to cut products with smooth edges from a sheet of metal that do not require finishing with a file. Therefore, many workers no longer know what it means to draw marks on the surface of the metal and then cut out the blanks. But not so long ago (perhaps 15 years ago) this operation was one of the main types. Marking was trusted only to very responsible and experienced craftsmen. But again, in conditions of individual and handicraft production, there is no alternative to this technology: people still make markings with a center punch, and then using various tools (chisel, hacksaw, vice, punching press and others) obtain pieces of sheet of the required size . Marking must be done on a marking plate. This is a special device. It will not be possible to accurately mark a part on an uneven and moving surface.
But straightening and straightening are not only actively used, but the need for these works only increases every year. And thanks to the rapid growth in the number of cars in our country and the inexperience of drivers, car repair shops make their revenue mainly from body work. Correction of cars involved in minor accidents is the main type of locksmith work in car services, not counting the repair and restoration of car engines and suspensions.
Preparatory operations also include bending. It can be carried out either using hand tools (vise and hammer, snail, etc.) or using specialized machine equipment.
Dimensional processing
This category includes filing the contour of products, drilling holes and cutting internal and external threads, as well as other types of metalwork. Their purpose and the main task- obtaining a product of a given shape and with surface roughness characteristics.
Filing is carried out with a file in order to smooth the surface after cutting with a chisel, as well as after pressure treatment (cold stamping). Filing is also often used to remove sharp burrs squeezed out by a cutting tool (mill or lathe).
Hole making is also one of the main types of plumbing work. Especially if you need to get a very precise center distance with a small tolerance. Modern jig boring machines and machining centers can handle this task very quickly. But in order to accurately drill holes by hand, you need very high qualifications. Not everyone is capable of such a task. Anyone can drill a few holes. But maintaining the given dimensions is a problem. Especially if you don’t have at your disposal not only a CNC machine, but also a conventional radial drilling unit. The accuracy of processing in this case affects the build quality of the product and its appearance. Plumbing and assembly work can be carried out successfully only if all technological requirements are met.
Thread cutting by a mechanic can be carried out in several ways: manually with a die and tap, and on screw-cutting lathe. In the second case, the mechanic must have the rank of machine operator. It should be noted that the majority of workers in vocational schools and colleges receive, in addition to the profession of a mechanic, also the profession of a general machine operator and have a corresponding document confirming the right to work on a machine. To obtain a thread on a machine, you must be able to use the screw feed of the machine, as well as sharpen the thread cutter. High-quality sharpening cannot be achieved without special devices and a diamond abrasive wheel for precise finishing. Therefore, it is recommended to use cutters with replaceable inserts for cutting internal and external threads.
The need for threaded connections arises almost everywhere. But this is especially important when performing all types of plumbing work in a boiler room, where special requirements are placed on the quality and reliability of pipe threaded connections. After all, in a boiler room, steam under high pressure is supplied through metal pipes, and if the threaded connections are loosened, a break in the steam line may occur, which will lead to injuries and injuries to the working personnel. Increased requirements for the reliability of threaded connections are also imposed upon the construction of structures made from metal profiles (whether transport bridges or metal building frames). In this area, as a rule, factory-produced hardware is used. However, a machinist may still be tasked with making a custom stud or bolt from some special material.
Fitting work
Fitting (or adjusting) work includes the following operations:
- polishing,
- lapping,
- fine-tuning,
- fitting,
- scraping.
All listed technological operations They have one thing in common - finishing.
Polishing cannot be classified as the main types of metalworking work, but its scope is very wide: from the preparation of polished sections for microanalysis of steels and non-ferrous metals and alloys to the preparation for use of casting molds made of tool steels (molds). Polishing is also carried out to give the products shine and attractive appearance(performs a purely decorative function).
To carry out polishing, special ones are used (such as “NERIS”). Such equipment has special rotating circles covered with felt or felt fabric. Special pastes are used as abrasives: chromium oxide (also called GOI (State Optical Institute) paste), aluminum oxide, diamond pastes of various fractions and other substances. There is also equipment on the market for polishing in an electrolyte environment. If the operation is performed manually, ordinary drills with special felt attachments are used, as well as ordinary fabric (felt or felt).
Lapping is carried out as follows: two parts that make up a friction pair are put into operation and subjected to a significant number of working cycles with a gradually increasing load (the clamping force and friction speed gradually increase). This operation is one of the most important types of plumbing and assembly work. Many people believe that lapping is unnecessary and unfairly diminish its role, and often neglect it altogether. This is a big misconception. After all, it is simply necessary when assembling heavily loaded units with rubbing parts: it smoothes out the microrelief, improves the fit of parts, which significantly increases the service life of the unit, prevents lubricant leakage, and so on.
A special place in any assembly production of products responsible appointment allocated to finishing operations - one more important view locksmith works. Their purpose is to eliminate repairable defects after machining and prepare the product for assembly (blowing, removing burrs and contaminants).
Classification of locksmith tools
The tools with which all types of plumbing and mechanical work are carried out are usually classified as follows:
- measuring
- marking,
- fixing,
- shock,
- cutting,
- assembly.
Each of the presented categories serves to perform specific tasks. It is worth considering some of the groups in more detail.
Clamping tool
The clamping tools are vices and clamps, as well as all kinds of pliers and pliers.
The vice is installed on a workbench and serves to fix workpieces for the purpose of their further processing. There are a large number of different types of vices depending on the size and purpose.
Clamps are designed to clamp one product to another. Most often, the need for their use arises when gluing surfaces.
Cutting tool
This is, without a doubt, the most significant and important group. The cutting category includes a large number of tools: a hacksaw for metal, scissors, chisels, wire cutters, needle files and files, scrapers for deburring, as well as drills, countersinks, reamers, counterbores, dies, taps, cutters, etc. Almost all the names are well known every person. IN this list Tools for manual processing as well as for machine processing are included. Some of them are universal and can be used both in machine cutting of metals and alloys and in manual cutting (for example, drills and taps).
The main difference between a cutting tool and other types is the formation of metal chips during operation. If the cutting modes are chosen incorrectly, the chips will curl and wrap around the working parts. Therefore, experimentally or using reference books, modes are selected in which the chips will be free-flowing. This will significantly extend the life of the tool and reduce the risk of injury to workers.
Measuring tool
This group includes rulers, tape measures, standards, gauges, plugs, calipers, depth gauges, bore gauges, micrometers and inclinometers.
All of the above tools have great practical significance. Without it, it is impossible to manufacture a product that meets all the requirements of technological documentation. Rulers and tape measures are necessary for measuring the dimensions of workpieces and parts. They allow measurements to be made with large errors.
To control the executive dimensions, it is necessary to use a caliper and a depth gauge. These instruments allow you to take measurements with an accuracy of hundredths of a millimeter.
Plug gauges are hardened cylindrical bodies with a handle. With their help, you can control the size of holes with a high level of accuracy. The pass-through plug should fit into the hole without effort; accordingly, the non-pass-through plug should not fall through. The tool is used not only when processing on machines, but also when carrying out some other types of metalwork. Which ones exist? alternative ways control of the executive dimensions of holes? You can use a standard caliper. But in this case, there is a high probability of obtaining large inaccuracies in the readings. So-called bore gauges with an indicator allow you to accurately measure holes. This is a rather sensitive instrument, so it must be handled very carefully and storage rules must be followed. The bore gauge is adjusted using a micrometer. The deviation of the indicator arrow determines whether the hole size is exceeded or underestimated.
Using probes and gauges, you can control linear dimensions (both internal and external).
Marking tool
These include scribers (a rod with a sharpened tip made of high-strength tool steel hardened with troostite), a compass (allows you to draw circles and arcs, as well as curves on the surface of workpieces for further cutting). Also included in this category of tool is a center punch. It is used to create recesses for drilling holes. Only with the help of a center punch can an accurate relative position of the holes be achieved. Without marking, the drill will constantly move to the side, as a result of which the interaxial distance, as well as the distance to the boundaries, will be violated.
Product assembly tool
Assembly operations are the main and most important class and type of plumbing work. Briefly, their purpose can be characterized as follows: obtaining a product from disparate parts that is ready for use for its intended purpose, or obtaining a mechanism assembly.
Even a simple layman, far from technology, knows that assembly is carried out using wrenches and screwdrivers. In some cases (when assembling very precise and critical components and mechanisms), there are requirements for the tightening torque of the nuts. In such circumstances, a torque wrench or ratchet wrench designed for a specific tightening force is used.
