Lesson topic: “Metal bending.”
Lesson type: study of labor techniques and operations.
Learning goals lesson:
Educational – to familiarize students with metal bending techniques. Teach students proper bending techniques sheet metal and wire in a vice using various devices, complying with labor safety requirements.
Developmental – develop independence by finding faults in drawings, develop skills in quick thinking, find ways to improve your work. Develop productive work skills, understand practical situations and independently implement the solutions found.
Educational – to form in students the desire for constant development of professional abilities and skills, the desire for self-control. Build independence and self-confidence. Develop interest in the profession. To instill in students a caring attitude towards locksmith's tool.
Materially technical equipment lesson: metal blank, marking tool, plumber's hammers, vices, round nose pliers, piece of pipe, measuring instruments, product standards, poster “Metal bending”, instructional and technological maps, table of evaluation criteria.
Venue: locksmith workshop.
During the classes
I. Organizational part (5 minutes)
Report from the headman about the presence of students. Checking work clothes and appearance studying.
II. Introductory briefing (45 minutes)
1. Statement of the topic and purpose of the lesson.
2. Updating previous knowledge
a) students (4, 5 people) receive cards with questions that they must answer in 15 minutes.
b) students answer the following questions using diagrams and layouts:
1. How to properly go to your workplace?
2. What safety rules must be followed in the workplace?
3. How to properly prepare a workplace for work?
4. When is it necessary to use metal straightening and what is it?
5. What tools are needed to straighten metal?
6. How do you straighten hot metal?
7. How are metal sheets straightened?
3. Formation of new concepts and methods of action:
3.1. Talk about the significance of this work for mastering the profession.
3.2. Consider new material and make a summary:
Metal bending is the giving of a new shape to a workpiece (or part thereof) by mechanical or manually by using special devices.
For manual bending of metal, a bench hammer, a wooden hammer (mallet), pliers or round nose pliers and various metal mandrels are used.
Thin wire is bent with round pliers, wire of larger diameter is bent in a clamp or on an appropriate mandrel. Reinforcing steel is bent using a pipe placed on the end of the rod. bending sheet metal and wires are made in a vice at the level of the jaws or using special devices - mandrels. To avoid crushing the workpiece, overhead squares made of softer metal are placed on the jaws. Bending is performed wooden hammer(with a mallet) or a plumber's hammer, but the blows are applied not to the workpiece, but to a wooden block; it pulls back the metal without leaving dents on it. The workpiece is secured so that the bend line is at the level of the corners, jaws of the vice or the edge of the mandrel. With light blows of a mallet or hammer, first bend the edge of the workpiece, and then the entire intended area.
When bending long workpieces, a metal strip or wooden block. Long sheets should be bent using a bending machine.
When bending, pipes are deformed and flattened, so before bending they are filled with dry sand and the ends are sealed wooden plugs. Then the pipe is heated over a fire and carefully, gradually bent on a mandrel. You can also insert a thick steel spiral into the pipe. After cooling and control, sand is poured out or the spiral is removed.
Typically, factories produce wire in rolls. Blanks required length cut off with pliers. The cut piece of wire must be straightened before processing. To give the wire workpiece the required form, it is subjected to bending. Wire bending is done using pliers and round nose pliers. Use pliers to clamp and bend the wire under the right angle. Details complex shape obtained using pliers. For the manufacture of ring-shaped products, cylindrical mandrels are used.
Safety precautions when bending metal. When bending metal in a cold or hot state, in order to avoid bruises and injuries, it is necessary to firmly strengthen the metal and pipes on the machines; monitor the serviceability of fences, electrical equipment, wires, starting devices and protective grounding.
Safety precautions for manual bending:
When working, securely secure the workpiece with the mandrel in a vice.
You can only work proper tool.
When cutting the workpiece, do not bring the wire close to your face.
Can't hold left hand close to the place where the workpiece is folded.
The hand holding the workpiece must be wearing a mitten.
Do not stand behind someone working and do not work if someone is standing behind you.
3.3. Review working drawings and diagrams. Technical requirements.
3.4. Disassemble technological sequence performing work in accordance with the assignment (Table No. 1).
3.5. Consider the tools, instruments and devices used.
3.6. Show working methods.
3.7. Warn about possible errors when performing work (Table No. 2).
3.8. Pay attention to self-control techniques.
3.9. Parse questions rational organization workplace.
3.10. Conduct instruction on safety rules and draw students’ attention to dangerous work practices.
3.11. Communicate grading criteria to students.
4. Reinforcement of the introductory briefing material:
Show proper organization workplace
Reproduce the correct techniques when bending metal.
How to bend wire correctly?
How to bend sheet metal correctly?
Why is consistency necessary when doing work?
How to check the correctness of the work.
Invite several students to repeat the work techniques in front of the group; make sure you understand.
Show typical mistakes when bending metal.
III. Student Exercise and Ongoing Instruction
1. Distribution of students by workplace.
2. Issuing practical assignments.
3. Issuance of technological documentation to students corresponding to the practical task.
4. Independent work studying under the guidance of a training master.
5. Targeted walk-through of student workplaces.
6. Current instruction:
Walking around students' workplaces to check:
a) maintaining consistency technological process;
b) correct use tools and equipment;
c) organization of the workplace;
d) student compliance with the rules of bladeless work;
e) quality of work.
IV. Final briefing (10 min.)
1. Summing up the lesson with analysis:
o fulfillment of the planned task,
o compliance with technology and safety precautions.
2. Conduct an assessment of the quality of the student’s work.
3. Point out mistakes made during the lesson.
4. Cleaning and handing over of workplaces.
5. Reflection:
o What significance do the knowledge and skills acquired in the lesson have for you personally?
o Did you help others or were you helped?
o What caused the most difficulties?
6. Homework: repeat from the textbook:
1. Rules and methods of performing work when bending metal.
2. Read the material about the tools used in metal bending.
Safety precautions.
General requirements security
To independent work on manual processing metal is allowed to persons at least 16 years of age who have undergone appropriate training and instructions on labor protection. Students must follow the rules of conduct and schedule training sessions, established modes work and rest.
When manually processing metal, workers may be exposed to the following hazardous production factors:
Injury to hands when working with a faulty tool;
Injury from metal fragments when cutting it.
Safety requirements before starting work:
Put on special clothing and ventilate the training workshop;
Check the serviceability of the tool and put it in its place;
When chopping metal, wear safety glasses and check the presence of a protective mesh on the workbench;
Check the condition of the vice; the jaws of the vice must be firmly secured;
Remove everything unnecessary from the workplace.
Safety requirements during operation:
Firmly secure the workpiece in a vice. Vise lever
Perform the work only with a serviceable tool.
To avoid injury, make sure that: the surface of the hammers and sledgehammers is convex and not knocked down. Tools with pointed shank ends (files, etc.) were equipped with wooden, tightly fitted handles of a fixed shape, without chips or cracks, with metal rings. Drums cutting tools(chisel, bit, punch, gluemeisel, etc.) had an unbroken surface. The chisel had a length of at least 150 mm, and its extended part was 60-70 mm;
When working with files, the fingers were on the surface of the file;
When cutting metal, a protective guard was installed metal grid with cells no more than 3 mm or an individual screen;
To avoid injury, do not check the quality of the sawn surface with your fingers;
Hold the sheet metal workpiece being cut when cutting with scissors with your hand in a mitten;
Use locksmith tools only for their intended purpose;
Do not use keys with a gap bigger size than the nut, do not lengthen the handle of the wrench by overlapping the grip of two wrenches.
When manually processing metal, the following protective clothing should be used and individual means protection: cotton robe, beret, mittens, safety glasses. In the event of an accident, the victim or eyewitness to the accident is obliged to immediately inform the foreman, who informs the administration of the institution about this. If equipment or tools malfunction, stop working and report it to the teacher or foreman. Students must follow the procedure for performing work, personal safety rules, and keep the workplace clean. Students who fail to comply with or violate labor safety instructions are held accountable, and all students are given unscheduled instruction on labor safety.
Rice. 1.double bench
Bench workbenches can be different designs, single and double, permanent and mobile. They can be made of wood or metal; Combined workbenches are also made - from wood and metal. Plate mechanic's workbench always made of hard wood. At the bottom of the table (under the stove) there is drawer for the tool. Depending on the design of the table, there is a cabinet with shelves on the right (or left) side of the drawer.
Safety requirements in emergency situations:
If a working tool fails, stop working and inform the teacher (teacher, foreman);
If you receive an injury, inform the teacher (master, lecturer) about this, who will provide first aid to the victim, and, if necessary, send him to the nearest medical institution and inform the administration of the institution about this;
If a fire occurs, immediately evacuate students from the training workshop, report the fire to the administration of the institution and the nearest fire department, and begin to extinguish the fire using primary fire extinguishing equipment.
Safety requirements after completion of work:
Organize your tools and work area. Do not blow away shavings and sawdust with your mouth or brush them away with your hand, but use a brush and a magnet for this purpose;
Conduct wet cleaning and ventilate the training workshop.
Remove protective clothing and wash your hands thoroughly with soap.
Measurements
TO universal measuring instruments - for dimensional control used in plumbing, include a folding measuring metal ruler or metal tape measure, a universal caliper, a normal caliper for external measurements, a normal caliper for measuring diameter, a simple caliper depth gauge, a universal protractor, a 90° square, and also compasses.
Rice. 2. Universal measuring instruments: a – measuring metal ruler; b - caliper; c – normal calipers; d – normal bore gauge; d – rod depth gauge; e – universal goniometer; g – flat square 90"
TO simple special tools - used in plumbing include: rectangular ruler; threaded template; single-sided prefabricated plug; double-sided limit stopper; the limit bracket is one-sided and the limit bracket is double-sided.
Rice. 3. Simple special tools for controlling dimensions: a – an angular ruler with a double-sided bevel; b – rectangular ruler; in - threaded template; g – probe; d – single-sided prefabricated plug; e – prefabricated double-sided limit plug; g – one-sided limit bracket; h – double-sided limit bracket
Universal caliper is a measuring tool used for internal and external measurements of length, diameter and depth. It consists of a guide rod, made integral with the jaw, which has two supporting surfaces (lower - for external and upper - for internal measurements), a slider, which is integral with the lower movable jaw for external measurements and the upper movable jaw - for internal measurements, clamping frame and retractable depth gauge rod. The guide rod has millimeter markings.
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 markings: flat and spatial. The markup is called flat, when lines and points are drawn on a plane, spatial – when marking lines and points are applied to a geometric body of any configuration.
Spatial markings can be made 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.
TO marking tool include: scriber, markers, marking compasses, punches, calipers with a conical mandrel, hammer, center compass, rectangle, marker with a prism.
TO marking devices include: a marking plate, a marking box, marking squares and bars, a stand, a thicknesser with a scriber, a thicknesser with a moving scale, a centering device, a dividing head and a universal marking grip, a rotating magnetic plate, double clamps, adjustable wedges, prisms, screw supports.
Measuring tools for marking are: a ruler with divisions, a thicknesser rod, a thicknesser 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 adding a compound that prevents the oil from drying out), red paint (a mixture of shellac and alcohol with the addition of dye), lubricant, washing and etching materials, wooden blocks and slats, small tin containers for paints and a brush. Simple marking and measuring instruments 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.
Flat or spatial marking details are 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); examination overall dimensions, as well as 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 center lines and centers of holes required for processing, certain straight or curved lines on the product. The purpose of marking is to mark persistent and noticeable marks on the part 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 slats), is applied to 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 carefully. 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.
Puller– this is a metalworking tool for removing from shafts gear wheels, couplings, pulleys, bearings, levers, etc. A bearing puller consists of two or three clamps (cheeks) and a clip connecting the arms of the clamps, bushings with internal thread, as well as from a screw with a hex or square head or handle.
Metal cutting
A bench chisel (Fig. 9) is a tool made of tool carbon steel U7A or U8A with a rectangular or rounded profile, one end of which has a wedge shape. Chisel dimensions: length 100–200 mm, thickness 8–20 mm, width 12–30 mm. A metalworking chisel is used for chopping or removing a layer of metal when precision processing is not required. It can also be used to cut, trim and trim material.
Rice. 4. Bench chisel
Depending on the type of material being cut or trimmed, the sharpening angle of the chisel is: 60° for steel, 70° for cast iron and bronze, 45° for copper and brass, 35° for zinc and aluminum.
The material to be cut (tin plate, strip iron, steel strip, profile, rod) should be placed on a steel plate or anvil so that its entire surface is adjacent to the surface of the plate or anvil. The material from which the workpiece needs to be cut can be secured in a vice. If the metal is longer than the plate or anvil, its overhanging end should be supported by suitable supports.
A sheet or piece of tin with the outline of the element marked on it is placed on a steel plate to cut the tin. The tip of the chisel is placed at a distance of 1–2 mm from the marked line. By hitting a chisel with a hammer, the tin is cut. By moving the chisel along the contour and simultaneously hitting it with a hammer, they cut out the shaped element along the contour and separate it from the sheet of tin.
Cutting an element from a thick one sheet material This is done first on one side of the sheet, then it is turned over to the other side and cut out completely (by moving the chisel along the resulting mark from the tip of the chisel). The cut element along the contour is processed with a hand file.
Before marking, bent or dented sheet metal should be straightened on the plate with a rubber or wooden hammer. Before laying the sheet on the slab during straightening, marking and cutting, the slab should be thoroughly cleaned and wiped. The tin must adhere to the slab with its entire surface. Do not use a dull or chipped chisel or a chipped or splintered hammer.
A chisel is used to cut material in cases where it is difficult or impossible to use scissors or a saw due to the complexity of the required part configuration, when the necessary scissors are not available, when the material being cut is too hard.
When cutting viscous materials, in order to protect the chisel from jamming, the cutting part of the chisel should be lubricated with oil or water and soap, which reduces friction and makes it possible to obtain a smooth cut surface.
Circumcision- This is the removal of the edge of the material using a chisel, as well as the removal of beads and sprues on the surface of the castings.
Kreutzmeisel- This is a metalworking tool that is similar to a chisel, but has a narrow or shaped cutting part. It is used for cutting rectangular or shaped grooves. There are several types of crossbars: rectangular, semicircular and special (Fig. 10).
Rice. 5. Kreuzmeiseli:a – rectangular; b – semicircular, grooved
A chisel is used for cutting, and a cross-section is used for cutting.
For mechanical cutting, a manual pneumatic hammer with a chisel inserted into it is used.
Pneumatic hammer set in motion compressed air. Pneumatic hammers are also used for riveting and construction work. Used as in indoors, and in open areas during installation and construction work.
The heads of chisels and crosspieces have beveled, ground surfaces rounded at the end. If the tip becomes dull or damaged, the cutting part of the chisel should be sharpened to the appropriate angle. After work, the tool must be cleaned of dirt and wiped with a cleaning cloth soaked in oil.
If safety requirements are not followed when cutting, cutting and trimming, a mechanic most often receives injuries to his hands or face from fragments of the materials or tools being processed. When working with a chisel or cross-cutting tool, wear safety glasses and gloves. The workplace of a mechanic working with a chisel must be fenced with a protective mesh.
Manual and mechanical straightening and metal bending
For straightening shaped, sheet and strip metal, use various kinds hammers, plates, anvils, sheet metal straightening rolls, hand screw presses, hydraulic presses, roller devices and gates.
Bending of metal depending on its thickness, configuration or diameter is done with a hammer using metal tongs or blacksmith's tongs on a straightening plate, in a vice or in molds or on an anvil. You can also bend metal in various bending fixtures, bending machines, press brake dies, and other equipment.
A hammer is a percussion instrument consisting of a metal head, a handle and a wedge (Fig. eleven.
Rice. 6. Plumber's hammer:
a – metal head; b – handle; c – wedge
The hammer is widely used in performing different operations plumbing; This is one of the main tools when performing locksmith work.
Flexible called the operation of giving metal a certain configuration without changing its cross-section and processing the metal by cutting. Bending can be done in a vice or on an anvil. Bending metal and giving it a certain form can facilitate the use of templates, core molds, bending dies and fixtures. Bending large quantity metal rods to give them a certain shape. is possible only in specially designed and manufactured dies and bending equipment for this purpose.
Rice. 7. Pipe bending device.
When straightening and bending metal, it is necessary to check technical condition tools used, correctly and accurately fix the material on a plate, in a vice or other device. The sleeves of clothing should be buttoned at the wrists, and mittens should be worn on the hands.
Related information.
Lesson topic:“Metal bending.”
Lesson type: study of labor techniques and operations.
Lesson learning objectives:
Educational – familiarize students with metal bending techniques. Teach students the correct techniques for bending sheet metal and wire in a vice using various devices, and compliance with labor safety requirements.
Developmental – develop independence by finding faults in drawings, develop skills in quick thinking, find ways to improve your work. Develop productive work skills, understand practical situations and independently implement the solutions found.
Educational – to form in students the desire for constant development of professional abilities and skills, the desire for self-control. Build independence and self-confidence. Develop interest in the profession. To instill in students a caring attitude towards plumbing tools.
Material and technical equipment of the lesson: metal blank, marking tool, metalworking hammers, vice, pliers, piece of pipe, measuring instruments, product standards, poster “Metal bending”, instructional and technological cards, table of evaluation criteria.
Location: locksmith workshop.
During the classes
I. Organizational part (5 minutes)
Report from the headman about the presence of students. Checking the student's work clothes and appearance.
II. Introductory briefing (45 minutes)
State the topic and purpose of the lesson.
Updating previous knowledge
a) students (4, 5 people) receive cards with questions that they must answer in 15 minutes.
b) students answer the following questions using diagrams and layouts:
How to get to your workplace correctly?
What safety rules must be followed in the workplace?
How to properly prepare your workplace for work?
When is metal straightening necessary and what is it?
What tool is needed to straighten metal?
How do you straighten hot metal?
How are metal sheets straightened?
3. Formation of new concepts and methods of action:
3.1. Talk about the significance of this work for mastering the profession.
3.2. Review new material and make notes:
Metal bending– is giving a new shape to a workpiece (or part of it) mechanically or manually using special devices.
For manual bending of metal, a bench hammer, a wooden hammer (mallet), pliers or round nose pliers and various metal mandrels are used.
Thin wire is bent with round pliers, wire of larger diameter is bent in a clamp or on an appropriate mandrel. Reinforcing steel is bent using a pipe placed on the end of the rod. Bending of thin sheet metal and wire is carried out in a vice at the level of the jaws or using special devices - mandrels. To avoid crushing the workpiece, overhead squares made of softer metal are placed on the jaws. Bending is performed with a wooden hammer (mallet) or a plumber's hammer, but the blows are applied not to the workpiece, but to a wooden block; it pulls back the metal without leaving dents on it. The workpiece is secured so that the bend line is at the level of the corners, jaws of the vice or the edge of the mandrel. With light blows of a mallet or hammer, first bend the edge of the workpiece, and then the entire intended area.
When bending long workpieces, a metal strip or wooden block is used. Long sheets should be bent using a bending machine.
When bending, pipes are deformed and flattened, so before bending they are filled with dry sand and the ends are sealed with wooden plugs. Then the pipe is heated over a fire and carefully, gradually bent on a mandrel. You can also insert a thick steel spiral into the pipe. After cooling and control, sand is poured out or the spiral is removed.
Typically, factories produce wire in rolls. Workpieces of the required length are cut with wire cutters. The cut piece of wire must be straightened before processing. To give the wire workpiece the desired shape, it is bent. Wire bending is done using pliers and round nose pliers. Use pliers to clamp and bend the wire at the desired angle. Parts of complex shapes are obtained using round nose pliers. For the manufacture of ring-shaped products, cylindrical mandrels are used.
Safety precautions when bending metal. When bending metal in a cold or hot state, in order to avoid bruises and injuries, it is necessary to firmly strengthen the metal and pipes on the machines; monitor the serviceability of fences, electrical equipment, wires, starting devices and protective grounding.
Safety precautions for manual bending:
When working, securely secure the workpiece with the mandrel in a vice.
You can only work with a working tool.
When cutting the workpiece, do not bring the wire close to your face.
Do not keep your left hand close to the fold of the workpiece.
The hand holding the workpiece must be wearing a mitten.
Do not stand behind someone working and do not work if someone is standing behind you.
3.3. Review working drawings and diagrams. Technical requirements.
3.4. Disassemble the technological sequence of performing the work in accordance with the task (Table No. 1).
3.5. Consider the tools, instruments and devices used.
3.6. Show working methods.
3.7. Warn about possible errors when performing work (Table No. 2).
3.8. Pay attention to self-control techniques.
3.9. Analyze issues of rational organization of the workplace.
3.10. Conduct instruction on safety rules and draw students’ attention to dangerous work practices.
3.11. Communicate grading criteria to students.
4. Reinforcement of the introductory briefing material:
Show the correct organization of the workplace
Reproduce the correct techniques when bending metal.
How to bend wire correctly?
How to bend sheet metal correctly?
Why is consistency necessary when doing work?
How to check the correctness of the work.
Invite several students to repeat the work techniques in front of the group; make sure you understand.
Show typical mistakes when bending metal.
III. Student exercise and ongoing instruction (5 hours)
Distribution of students by workplace.
Issuance of practical assignments.
Issuance of technological documentation to students corresponding to the practical task.
4. Independent work, studying under the guidance of a training master.
5. Targeted walk-through of student workplaces.
6. Current instruction:
Walking around students' workplaces to check:
a) compliance with the sequence of the technological process;
b) proper use of tools and equipment;
c) organization of the workplace;
d) student compliance with the rules of bladeless work;
e) quality of work.
IV. Final briefing (10 min.)
fulfillment of the planned task,
compliance with technology and safety precautions.
What significance do the knowledge and skills acquired in the lesson have for you personally?
Did you help others or were you helped?
What caused the most difficulties?
Summing up the lesson with analysis:
Conduct an assessment of the quality of the student’s work.
Point out mistakes made during the lesson.
Cleaning and handing over of work places.
Reflection:
Homework: according to the textbook “ General course plumbing" repeat:
1. Rules and methods of performing work when bending metal.
Table No. 1
| Training assignments. |
|
| Bending of sheet and strip material. |
|
| Bending a rectangular bracket using simple tools. |
|
| Bending the ear with round pliers |
|
| Bending of clamps in round mandrels. |
|
| Metal bending round section using devices. |
|
Table No. 2
| Typical bending defects, causes of their occurrence and methods of prevention |
||
| Method of warning |
||
| When bending a corner from a strip, it turned out skewed | Incorrect clamping of the workpiece in the vice | Fasten the strip so that the marking mark is exactly located at the level of the vise jaws. Check the perpendicularity of the strip to the jaws of the vice with a square |
| The dimensions of the curved part do not correspond to the specified ones | Inaccurate calculation of development, incorrectly selected mandrel | Calculate the development of the part taking into account the allowance for bending and subsequent processing. Accurately mark bending points. Use mandrels that exactly match the specified dimensions of the part. |
| The length of the workpiece is not enough to obtain the right size details | Incorrect workpiece length | The workpiece must be made 10-15 mm larger than required according to the drawing, and at the end of the work, the excess must be removed with pliers. |
| When bending the clamp, dents and nicks remain | Do not put a piece of iron strip | Place a piece of iron strip between the canvas and the part. |
| Dents (cracks) when bending a pipe with filler | The pipe is not packed tightly enough with filler | When filling the pipe with filler (dry sand), place it vertically. Tap the pipe on all sides with a hammer |
The history of the appearance of jardiniere stands and their use by people goes back to antiquity.
Jardiniere. The name itself, coming from the French jardin - garden, suggests that this is an option home garden, presented in miniature. Jardinieres were pieces of furniture on which pots with plants were placed. They consisted of a support, usually the height of a table, and a box, round or square, into which earth was poured or flower pots were placed. Jardinieres were intended for rooms or greenhouses. Until the invention central heating flowers could not be placed on the windowsill, as they could freeze there - hence the need for special stands for them. Greenhouses were very popular among wealthy people in the 18th and 19th centuries. Tropical fruits were grown on Russian estates for the master's table. Round jardinieres were often vase-like and made from majolica.
Flexible. The deformation of a material under the influence of external forces is called flexible. Form changes can occur to varying degrees.
The main tool for bending and straightening is bending pliers. The main dimensions of bending pliers are in the range of 12-16 cm.
Types of jewelry bending pliers:
A - with a flat surface of the jaws, i.e. pliers;
B - with the same width of jaws - parallel jaws;
B - with jaws pointed towards the end - pointed jaws;
G - round-nose pliers, i.e., pliers with round-conical jaws and slightly pointed jaws at the end;
D - splint pliers - they have a flat surface of one sponge and a convex surface of the other;
E - flat-pointed forceps;
F - grooved tongs, in which one jaw has a round shape, and on the working surface of the other there is a semicircular groove.
When bending jewelry, auxiliary devices are often used. These include all kinds of crossbars, mandrels, and hand vices. For bending sheets or strips, metal or wood base plates with a forming groove are usually used.
Edit. Correcting distortions resulting from metal processing is called straightening.
Straightening can be done manually and with the help of special devices: metal, textolite and wooden hammers, hardened steel straightening plates (flakaisens), anvils, pliers, crossbars, mandrels, ordinary and special punches.
· Straightening of a wide sheet or strip is carried out on a straightening plate. Dents are removed by tapping with a hammer.
· Straightening of wire and tubular workpieces is carried out either by pulling them with pinangs around the mandrel, or by pulling them through the hole of the drawing board.
· Straightening with the help of tools and devices of sheet, strip and rod material is carried out on a flakeisen or sperak with hammers with a round or rectangular shape striker. The working surface of the tool must be well polished and protected from nicks and scratches. Before editing, the material is annealed.
· Straightening of wire and tubular workpieces is carried out either by pulling them
· Straightening of stamped products and parts comes down to straightening the tires of the rings to give them the correct round shape. The conical shape of the crossbar allows you to edit rings with the most different diameters Along with round ones, there are oval, square, rectangular and hexagonal crossbars. The parts are straightened with a textolite or wooden hammer until they completely adhere to the crossbar.
Hammer and types of strikers used:
A - flat; B - spherical;
B - wedge-shaped rounded
Crossbar (A) and types of mandrels (B)
Anvils are necessary to create a rigid base and process workpieces jewelry. Depending on the working surface, the following anvils are used: leveling plate (flakeisen), shperak (table and attachment) and crossbar. Their working surface must be heat treated And polished.
CONCLUSION
Occupational safety rules when bending metal
* securely secure workpieces in a bench vise or other devices;
* work only on working equipment;
* plumber's hammers must have good handles, be tightly seated and wedged;
* do not place mandrels and tools on the edge of the workbench;
* when bending wire, do not hold your left hand close to the bend;
* do not stand behind the worker;
* perform the work carefully so as not to damage your fingers;
* work in gloves and buttoned-up gowns.
So, tools must be selected based on how complex the work you are going to do is.
But you should always remember that the more perfect a particular tool is, the better the work can be done, and, in addition, it will be easier and more enjoyable for you to create or repair something with your own hands, using perfect technology.
The student must know: purpose and methods of metal bending; tools and devices; technical equipment; organization and rules for maintaining the workplace; basics of industrial sanitation.
The student must be able to: bend rods, strip steel, rolled angle steel in the correct sequence; bend pipes in cold and hot conditions; properly organize the workplace; comply with safety regulations; eliminate defects that occur during metal bending.
1. Why is the length of the workpiece for subsequent bending calculated along the neutral line?
2. Why does deformation not occur when using filler when bending pipes?
3. In what cases and why are hammers with soft inserts used when bending?
4. What is taken into account when choosing percussion instrument for bending?
5. Why is it not necessary to use special bending devices when bending pipes?
use of filler?
6. What phenomena occur during bending?
7. What pipe bending methods are used in practice?
8. What defects occur when bending metal and how to eliminate them?
9. What tools and devices are used when bending metal and what are they used for?
10. What safety rules must be followed when bending metal?
General information and filing techniques"
Target: introduce students to technical requirements for the upcoming work in the metalwork shop; teach how to use tools and devices, sequences of filing techniques for various workpieces, cylindrical rods, shaped surfaces complex profile; with safety rules when filing metal; with labor protection and fire safety
