If production requires a large number of metal products or blanks of the same sample, it is advisable to use the stamping method. Metal stamping is carried out from sheet material, which is specially deformed to the desired shape by pressure. Stamping of metal products has been used since ancient times: many centuries ago, our ancestors made jewelry, weapons and household items in this way. Then it was done manually and at a much lower speed, but now the process is automated, and the production of one part takes much less time.
The history of the process
The mechanization of the process began in the 1850s. Then machines began to be connected to the metal stamping process, which significantly accelerated the production process and increased the quality of products.
And in the century, there was a new upsurge in the manufacture of metal parts by stamping, which gave rise to the era of the automotive industry. With the help of this method, car bodies and some parts of mechanisms began to be created.
Car parts
Since the 1930s. stamping of sheet metal parts began to be used in manufacturing plants aircraft and sailing ships. And after 20 years, it was introduced into the rocket industry.
The metal stamping method has become popular for a number of reasons:
- the production process is mechanized and automated using rotary conveyor lines, which allows you to speed up production as much as possible;
- it is possible to manufacture parts of any shape and parameters, which can be either a blank or a finished product;
- there is a high accuracy of the manufactured parts, which allows them to be replaced with each other without reworking with a tool or on equipment;
- it is possible to manufacture lightweight products of high strength.
Stamping of metal parts is also used for massive products that are used as blanks in the construction of cars, ships, aircraft, and for small lightweight parts such as hour hands. Stamping owes its popularity high speed the production of such products and the almost limitless possibilities of the production of non-separable parts of any size, which is so important in the construction of ships and trains.
Stamping technology
For the manufacture of parts by stamping, a metal sheet, a thin steel strip or strip is used.
Most often, parts are made by cold stamping of sheet metal. With this type of production of parts, the metal acquires additional strength, which increases the service life of the product.
Hot forging is used when the equipment cannot deliver the power required to deform the cold metal into the desired shape. Or when making a product made of non-ductile metal. Sheets for the manufacture of parts by the hot method are taken with a thickness of less than 5 mm.
The further choice of production technology depends on how you need to influence the metal, that is, the technology for changing the shape of the product differs from that used for separation. As a result of the separating operations, a part is separated from the part.
This can be done in a curve or in a straight line or along a contour. The metal is separated by shifting parts of the workpiece in different directions. Several operations are used for separation, in which a press with special tools is used.
Types of separation operations:
- Parting - parts of a metal workpiece are divided along a curly line or in a straight line. The press for this type of operation is called scissors. With the help of this operation, ready-to-use parts and blanks are produced, which are then refined in other ways.
- Notching is an operation of incomplete cutting of a part of a workpiece under pressure while maintaining the integrity of the part.
- Trimming - a small part of the workpiece is removed, while part of the metal goes to waste.
- Punching - holes of various shapes are formed in a sheet of metal. Some of the base metal will be considered waste and must be disposed of.
- Cutting - forms a product from a workpiece, the contour of which is closed.
- Scraping - allows you to remove uneven edges and give the product a neat look by aligning its edges.
- Punching (notching) - a recess is made in the product with a cone-shaped tool.
Form-changing stamping of parts also has several types. This type of operation is used to change the shape and size of a sheet metal blank without destroying the material.
Types of shaping operations:
- Flanging holes - formation of sides of the desired shape and size around the holes of the blank.
- Flanging the contour - forming the sides of the desired shape and size along the contour of the product. Typically this method is used to process pipe ends to secure flanges.
- Exhaust - volumetric stamping, as a result of which spatial products are obtained from a flat sheet of metal, hollow inside. In this way, parts of hemispherical, box-shaped, conical, cylindrical and other shapes are made. The hood can be sequential, with a flat clamp in a flat die, or with a hook.
- Crimping - Tapering the ends of sheet metal parts that are hollow inside using a tapered die. The end of the part is inserted with great force into the funnel of the die.
- Bending - metal blanks are given the required bend in design. There are several types of bending, depending on the final shape of the product: V-shaped or one-angled, U-shaped or two-angled, multi-angled, pipe and curved.
- Forming - while the contour of the product remains unchanged, the size and shape of its sections change. There are several types of molding: it can be with a preliminary set, or it can be performed with a cylindrical punch with a flat end.
Hot metal stamping, automated lines
Features of cold stamping
Cold stamping is suitable not only for products made of alloyed and carbon steels, but also for aluminum and alloys of these metals. With this method, the choice of stamped materials can go beyond metals. Stamps for this type can be used to make parts from cardboard, leather, polymer alloys and rubber.
Products, for the manufacture of which cold stamping of metal was used, are distinguished by high strength, accuracy of parameters and shapes, as well as surface quality.
In some cases, the surface finish corresponds to grade 8. Typically, the surface finish of the part is from grade 2 to grade 6, which is average. But here you need to take into account the production speed, which is at the highest level.
But at the same time, when processing metal by cold stamping, the plasticity of the material decreases. Due to the increase in strength, the metal becomes brittle, which is one of the undeniable disadvantages of this type of metal processing.
To prevent these negative moments between operations that are performed during cold forming, the workpiece is exposed. This is called recrystallization annealing.
Finished products made using this technology combine the increased strength of a cold-stamped product and the ductility that the metal had before processing.
To select the press used and design dies, you need to know and take into account a large number of properties of the raw materials from which the products will be made. Otherwise, the quality of the products or the equipment itself may suffer.
To perform stamping operations for each type of product, an individual stamp is made according to the required parameters. This is done in a few steps:
- A sketch of the stamp of the required configuration is drawn up.
- The cutting scheme of the material is studied and checked in a specialized program on a computer.
- If a program or a person has identified a discrepancy between the sketch and the real requirements, the sketch is edited.
- The design is checked for compliance with the dimensions.
- The sketch indicates the exact dimensions and location of the holes on the working side of the stamp.
At the preparatory stage of stamping, the following is taken into account:
- Electrical conductivity and magnetic conductivity of the material used.
- Resistance to mechanical stress and hardness of the metal.
- The toughness of the metal used.
- Workpiece weight.
- The wear resistance of the metal and its resistance to corrosion, which affects the life of the stamped product.
- Heat resistance and thermal conductivity of the processed metal.
Equipment
Sheet metal stamping is done using a press and a die. The press is used to create pressure, that is, the stamping process itself, and the stamp gives the product the desired shape. The stamp is made of tool steels and consists of a punch and a matrix.
The deformation process takes place with the help of a punch and a matrix at the moment of their convergence. Movable is the upper half of the stamp, fixed on the press, namely on its slider.
The lower half remains motionless and rests on the working surface of the equipment. If not steel is stamped, but the material is soft, then the working parts of the stamp can be made of polymer alloys or wood.
In the manufacture of a single piece of an especially large size by stamping, it is usually not a press that is used, but a special device made of a cast iron or concrete matrix and a container with a liquid (usually water). A sheet of metal is placed on a die with a liquid punch above it.
Concrete matrix fixture
To create the pressure in the liquid necessary to deform the metal into the desired shape, a charge based on gunpowder is undermined in the container or an electric discharge of sufficient power is imparted to the water.
For cutting on sheet metal, not a press is used, but scissors. They are of several types:
- with parallel knives;
- disk;
- guillotine;
- vibrating.
The most commonly used scissors are vibration type.
For high-quality manufacturing of products, you need to carefully choose a press for each type of operation and material to be processed. There are several types of presses:
- Hammer (maximum speed up to 20 m / s).
- Hydraulic press (maximum speed up to 0.3 m / s);
- Crank car (maximum speed up to 0.5 m / s);
- Rotary machine (maximum speed 8 m / s);
- Impulse punching machine (maximum speed up to 300 m / s).
Crank machines are suitable for most types of operations. They can have from one to four crank mechanisms. The principle of operation of the crank mechanism can be described according to the diagram:
- The drive electric motor transmits the movement to the crank shaft through a kinematic chain, which consists of a friction clutch and a V-belt transmission.
- An adjustable connecting rod drives the crank slide.
- The foot pedal through the clutch starts the working stroke of the press.
Equipment for stamping products with complex configurations can have several sliders.
Video: Sheet Stamping
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One of the directions of LLC "Plant Spetsstanmash" is the development, design and manufacture of dies for metal stamping.
With solid experience behind them, our qualified specialists can guarantee high quality manufactured equipment, strict adherence to all customer requirements, performance of work within the agreed time frame.
Stamps are necessary for the manufacture of similar parts (stamping) by applying high pressure to the workpiece, during which the metal is deformed according to a pre-prepared template.
Stamps are made to order, they are subject to high requirements for reliability, accuracy and quality, since such equipment directly depends on appearance manufactured products. With the help of stamps, both the simplest parts and quite complex ones are made.
The minimum production time is 10 working days and depends on the characteristics of a particular product, the availability of a suitable blank and other factors.
You can order from us not only equipment, but also such a necessary service in the industry as metal stamping and other metalworking services.
Materials used
For cold stamping, the following are used:
- alloy and carbon steel,
- alloys of copper and aluminum.
Non-metallic materials are also used - leather, ebonite, plastic and rubber. Workpieces of any shape are perfect for stamping: strips, coils and sheets.
The processing of plastic materials by cold stamping significantly expands the capabilities of manufacturing enterprises. Parts made in this way are characterized by increased strength and low weight.
With the help of dies, molded variations of a wide range are produced: from inconspicuous hands on wristwatches to massive spars of trucks. In car building and shipbuilding, large-scale mechanical units are used, made by sheet stamping, after which they are welded into a single piece. By ordering the manufacture of dies from us, you can carry out the production of even the most complex thin-walled parts.
Production of stamps or stamping services of any complexity, ordered in LLC "Zavod Spetsstanmash", take a minimum amount of time due to the fact that we have established our own efficient production. Manufacturing of equipment and execution of stamping is carried out exclusively by experienced specialists in modern workshops.
Stamping like technological process processing of workpieces made of metal makes it possible to obtain finished products of a flat or volumetric type, differing both in their shape and size. A stamp attached to a press or other type of equipment can act as a working tool when performing stamping. Depending on the conditions of execution, metal stamping is hot and cold. These two types of this technology involve the use of different equipment and compliance with certain technological standards.
Technology features
You can get acquainted with the requirements of GOST for metal processing by stamping by downloading the document in pdf format at the link below.
In addition to the division into hot and cold, stamping of metal products is subdivided into a number of other categories, depending on its purpose and technological conditions. So, stamping operations, as a result of which a part of a metal workpiece is separated, are called separating. This includes, in particular, cutting, chopping and punching metal parts.
Another category of such operations, as a result of which a stamped sheet of metal changes its shape, are forming forming operations, often referred to as forming. As a result of their implementation, metal parts can undergo drawing, cold extrusion, bending and other processing procedures.
As noted above, there are such types of stamping as cold and hot stamping, which, although they are implemented according to the same principle, which involves the deformation of the metal, have a number of significant differences. , assuming their preheating to a certain temperature, is used mainly in large industrial enterprises.
This is primarily due to the rather high complexity of such a technological operation, for the high-quality performance of which it is necessary to make a preliminary calculation and precisely observe the degree of heating of the workpiece being processed. With the help of hot stamping, critical parts such as boiler bottoms and other hemispherical products, hull and other elements used in shipbuilding are obtained from sheet metal of various thicknesses.
To heat metal parts before hot stamping, heating equipment is used, which is able to provide an accurate temperature regime. In this function, in particular, electrical, plasma and other heating devices can be used. Before starting hot stamping, it is necessary not only to calculate the heating rates of the workpieces, but also to develop an accurate and detailed drawing of the finished product, which will take into account the shrinkage of the cooling metal.
When making metal parts, the process of forming a finished product occurs only due to the pressure exerted by the working elements of the press on the workpiece. Due to the fact that the blanks are not preheated during stamping by cold technology, they are not subject to shrinkage. This allows the manufacture of finished products that do not require further mechanical revision. That is why this technology is considered not only more convenient, but also an economically viable processing option.
If a qualified approach to the design of the dimensions and shape of blanks and to the subsequent cutting of the material, then it is possible to significantly reduce its consumption, which is especially important for enterprises that produce their products in large batches. The material, the workpieces from which are successfully stamped, can be not only carbon or alloy steels, but also aluminum and copper alloys... Moreover, a properly equipped stamping press is successfully used for processing workpieces made of materials such as rubber, leather, cardboard, polymer alloys.
Separation punching, the purpose of which is to separate a part of the metal from the workpiece being processed, is a very common technological operation used in almost every manufacturing enterprise... These operations, which are carried out using a special tool mounted on a stamping press, include cutting, punching and punching.
In the process of cutting, metal parts are divided into separate parts, and this separation can be carried out along a straight or curved cutting line. Various devices can be used to perform cutting: disk and vibration machines, guillotine shears, etc. Cutting is most often used to cut metal blanks for their further processing.
Punching is a technological operation during which parts with a closed contour are obtained from a metal sheet. With the help of punching, holes of various configurations are made in sheet metal blanks. Each of these technological operations must be carefully planned and prepared in order to result in a high-quality finished product. In particular, the geometric parameters of the tool used must be precisely calculated.
Perforated metal sheet is obtained by punching holes on a punch press
Technological operations of stamping, during which the initial configuration of metal parts is changed, are forming, bending, drawing, flanging and crimping. Bending is the most common forming operation, during which bending areas are formed on the surface of a metal workpiece.
Stretching is a die forging, the purpose of which is to obtain from a flat metal part bulk product. It is with the help of drawing that the metal sheet is transformed into products of a cylindrical, conical, hemispherical or box-shaped configuration.
Along the contour of sheet metal products, as well as around the holes that are made in them, it is often necessary to form a rim. Flanging successfully copes with this task. This processing, carried out with a special tool, is also subjected to the ends of the pipes on which the flanges must be installed.
With the help of crimping, unlike flanging, the ends of pipes or the edges of cavities in sheet metal blanks are not expanded, but narrowed. When performing such an operation, carried out using a special conical matrix, external compression of the sheet metal occurs. Forming, which is also one of the types of stamping, involves changing the shape of individual elements of a stamped part, while the outer contour of the part remains unchanged.
Bulk stamping, which can be performed using various technologies, requires not only careful preliminary calculations and the development of complex drawings, but also the use of specially manufactured equipment, therefore, it is problematic to implement such a technology at home.
Tools and equipment
Even the processing of soft metals, in particular aluminum stamping, requires the use of special equipment, which can be guillotine shears, crank or. In addition, the ability to calculate material consumption and develop technical drawings is required. In this case, one should take into account the requirements that the corresponding GOST contains.
Stamping, which does not require preheating of the workpiece to be processed, is performed mainly on hydraulic presses, the production of which is regulated by GOST. A variety of serial models of this equipment allows you to select a machine for the production of products of various configurations and dimensions.
Choosing a press to perform stamping, first of all, one should orientate the tasks for the solution of which it is necessary. For example, punching equipment is used to perform technological operations such as punching or punching. simple action, the slider and the washers of which make a small stroke during processing. In order to carry out the extraction, double-acting equipment is required, the slider and washers of which make a significantly greater stroke during processing.
According to its design, as indicated by GOST, equipment for stamping is divided into several types, namely:
- single-crank;
- two-crank;
- four-crank.
On the presses of the last two categories, sliders of larger sizes are installed. However, regardless of the design, each stamping press is equipped with a die. The main movement, due to which the workpiece is processed on the stamping press, is performed by the slider, the lower part of which is connected to the movable part of the stamp. To impart such a movement to the press slider, the drive motor is connected to it by means of such elements of the kinematic chain as:
- V-belt transmission;
- starting clutch;
- washers;
- crank shaft;
- connecting rod, with which you can adjust the size of the working stroke of the slider.
To start the slider, which makes a reciprocating movement towards the working table of the press, a foot press pedal is used, which is directly connected to the starting clutch.
The four-rod press differs in a slightly different principle of operation, the working bodies of which create an effort with a center in the middle of a quadrangle formed by four connecting rods. Due to the fact that the force created by such a press does not fall on the center of the slide, this device is successfully used to manufacture products of even very complex configuration. Presses in this category, in particular, are used in order to produce asymmetric products with significant dimensions.
To make products of a more complex configuration, use pressing equipment pneumatic type, design feature which is that it can be equipped with two or even three sliders. In a double-acting press, two sliders are used simultaneously, one of which (external) secures the workpiece, and the second (internal) stretches the surface of the metal sheet being processed. The first in the operation of such a press, the design parameters of which are also regulated by GOST, is the external slider that fixes the workpiece when the lowest point is reached. After the inner slider has done its job of drawing the sheet metal, the outer tool rises and releases the workpiece.
The manufacture of parts by stamping is at the forefront of metal forming technology and is used in various industries.
Of particular importance is the stamping of metal products from sheet metal. It is based on plastic deformation of the metal without heating it using special stamps. This method of plastic deformation of parts is widely used for the manufacture of parts of various sizes and complex shapes with high precision, which cannot be done using other processing methods.
They are used for the assembly of large-sized products in the machine-building industry, in the automotive and shipbuilding industries, as well as in the instrument-making industry and everyday life, where various miniature parts are often required.
Stamping is the process of shaping parts into the desired shape and obtaining a document-specific size by mechanically acting on them using pressure. The main direction of stamping is the production of parts from blanks, which are used as sheet metal. Under the action of the compressive force, the workpiece is deformed and acquires the desired configuration.
Distinguish between hot stamping with heating the workpiece and cold stamping without preheating it. Sheet metal parts are stamped without preheating.
Deformation by pressure with heating of the workpiece is used in the manufacture of parts from metal that does not have sufficient ductility, and is mainly used in the production of small batches of bulk products from a metal sheet having a thickness within 5 millimeters.
The technological process of hot stamping of metal largely coincides with the sequence of operations for cold working of blanks. The difference lies in the preheating of the initial blanks in furnaces to a temperature that ensures the plasticity of the metal. In this case, the degree of warpage of the part during cooling is taken into account, as well as its tightening during deformation processing, which affects its size. To eliminate deviations from the required dimensions for parts obtained by hot stamping, large tolerances are made.
In the production of stamped sheet metal parts, the cold stamping method is mainly used.
Cold stamping of sheet metal
The technology of cold deformation of sheet products using stamps implies changing the shape and dimensions of the product while maintaining their original thickness.
Strips, sheets or thin strip, mainly made of low-carbon and ductile steels, as well as copper, brass (containing over 60% copper), aluminum, magnesium, titanium and other ductile alloys are used as a material for the production of stamped products by the cold method. The use of alloys with good ductility for stamping is due to the fact that they are easily amenable to deformation change.
To carry out cold stamping of sheet metal, various operations are used, which depend on the task of achieving a certain shape of the workpiece. They are subdivided into dividing and shaping influences.
1. In the case of separating deformations, the workpiece material is partially separated along a predetermined contour. The separation is carried out by shifting a part of the metal in relation to the main workpiece. Such operations are cutting, punching and others.
Let's consider how some operations of a separating nature are carried out.
Cutting
When cutting, a certain part is separated from the part by cutting it along a curly or straight line. This separation operation is performed using a press made in the form of a different design.
This operation is mainly intended to prepare the workpiece for other processing methods.
Punching
An operation called punching is used to create holes of different shapes in a workpiece. Part of the metal is completely removed from the workpiece during punching, and its weight is reduced.
The figure shows a diagram of the punching process.
Felling
With the help of the punching process of a metal part, the finished product has a closed loop.
The figure shows a diagram of the manufacture of a part using punching.
2. Shaping deformations include a change in the shape and size of the product when moving its individual areas, which does not lead to its general destruction. These include stretching, bending, embossing, twisting, crimping, and other operations.
Let's consider some types of operations that do not lead to physical destruction of the form.
Hood
With the help of drawing from sheet flat workpieces, hollow volumetric products are obtained. For example, in this way, parts are made in the form of a hemisphere, cylinder, cone, cube and other types. The figure shows the different options for performing the hood.
Bending
With the help of the operation, the product is given a given shape of its bending. Depending on the type of bending, such an operation makes it possible to obtain curved products of different configurations. Some of them are shown in the figure.
Relief molding
This type of operation implies the modification of the local parts of the product, its external configuration remains unchanged. The figure shows a diagram of some of the forming operations:
It is also possible to use combined operations, including the division and shaping of one part.
The technological process of carrying out cold stamping consists of stages that are related to the nature of the deformation operation and depend on the type of stamping equipment used.
The development of the technical process is carried out in the following sequence:
- The structure of the main operations is indicated, including their nature, number and sequence of execution.
- The calculation of the initial, intermediate and finished dimensions of the part is performed, as well as the required deformation forces to achieve the desired result.
- Held documenting technological process.
Additional operations can be introduced into the technical process, with the help of which the workpiece is brought to a form that is convenient for processing. These include cleaning, straightening sheets, applying grease, and other operations.
Stamping press for metal
All operations of cold stamping can be carried out with special equipment, the main of which is a stamping press. Its device can be based on mechanics, or using hydraulics.
Mechanical types include:
- eccentric presses;
- presses using a crank mechanism.
For punching, punching and drawing operations, a crank-type stamping press is used.
The device and principle of operation of a crank-type press
Any press designed for stamping products includes the main units, which include: a mechanism that drives it and a device that directly pushes.
The operating mechanism is a crank shaft that is driven by an electric drive. For this, the electric motor, when the flywheel rotates, transmits the rotation to the crank mechanism using a gear transmission.
Performing reciprocating actions, the crank slider drives the punching device, which, with a pressure force, carries out plastic deformation.
The main parts of such a press are made of high-strength steels and are additionally reinforced to give the required rigidity.
Hydraulic press device
Hydraulic metal stamping press is used to create volumetric shapes by punching metal.
The principle of operation of such a mechanism is based on the pressure of a liquid placed in two reservoirs, which are equipped with pistons. The tanks are connected by a pipeline. As a result of the pressure in the liquid, which occurs at the time of its injection into the cylinder from another reservoir, it is transferred to the slider and sets it in motion. When moving, the slider pushes the workpiece with great effort.
Manufacturing of dies for metal cold stamping
The working device of any press machine is the stamp itself. It includes two working parts called a die and a punch. In the process of work, only the upper part of the stamp is movable - the punch, fixed on the slider. The matrix is located at the bottom and remains stationary.
Deformation of the sheet is carried out while pressing the punch to the matrix with the workpiece located on it.
Increased requirements are imposed on the development of drawings and the manufacture of dies for the press, since the correctness of the formation of the product depends on their accuracy.
Such work is carried out in stages in the following sequence:
- a sketch of the stamp is drawn up;
- with the help of a computerized die scheme, compiled according to special program, the rational cutting of the material is checked;
Allows you to make flat or three-dimensional products.
Manufacturing takes place by means of dies that are attached to the press, or using other elements. There are two types of sheet metal stamping: hot stamping and cold stamping.
In the article, we will analyze how hot differs from cold, what standards must be observed in the process, and you will also find out if it is possible to make parts using this method with your own hands at home.
How does stamping work?
Depending on what technological standards are used, the stamping of parts can vary significantly.
The first type of stamping is cutting, chopping or punching material - it is called dividing.
There is also an option for stamping, when forming, drawing, cold extrusion and other manipulations with sheet metal occurs.
There are also hot and cold stamping of sheet metal.
Hot stamping is used only in large-scale production: using this method, the bottoms for the boiler, various parts in the form of hemispheres, buoys, etc. are manufactured.
Typically, hot stamping is used to make parts from which hulls and other shipbuilding-related items are made.
To get a three-dimensional or flat part, you need, first of all, a piece of sheet metal up to 4 mm thick.
Before starting work, a calculation is always carried out and the heating standards are observed - this is quite thin and hard work therefore hot stamping is not used at home.
Otherwise, the technology and calculation are similar to the cold stamping method, which we will talk about further.
Before starting work, you need to make a calculation and draw up drawings of parts, while the calculation should take into account that the metal is pulled during cutting, punching or bending.
In hot stamping, special equipment is used to heat the parts, such as fired or electric ovens, or other electric heating equipment.
You also need to ensure that the norms of the process and the correct calculation are followed.
In cold forming, the press is created using pressure and such equipment is not used.
The cold type of metal stamping is more convenient, because in this case, it is possible to manufacture finished products that do not need additional cutting.
During cold stamping, it is possible to produce both a volumetric and a flat part of a large or small size.
In general, the metal stamping technology is an advantageous procedure, since it assumes a reduction in material consumption at a high productivity. This is especially noticeable in the mass production of parts.
Cold stamping of parts is carried out with carbon steel or alloyed steel, as well as aluminum and copper alloys.
Cold forming equipment is capable of processing not only metal objects, but also work with cardboard, leather, rubber, plastic and other elements.
Cold stamping can be of two types: separating and forming.
Parting metal punching is the cutting, punching or punching of parts.
Part cutting involves dividing a metal workpiece into parts along predefined curves or straight lines.
Cutting is widely used in production - with its help, finished parts are made, or sheet metal is cut, dividing it into strips of the desired size.
Cutting requires special equipment, namely disc or vibrating, guillotine or other professional shears.
Sheet metal punching technology consists in the production of parts with a closed circuit. And the punching process is used to make holes in the part of the required shape.
Stamping of blanks can be done either by hand or to order. However, with independent work you need to comply with the prescribed standards, which is not so easy.
This process includes the following elements: bending, stretching, flanging, crimping and forming. The bending process creates bending parts.
When drawing from a flat workpiece, a volumetric hollow spatial part is produced.
By drawing, it is possible to make objects of a cylindrical, hemispherical, box-shaped or conical shape from blanks.
When flanging, beads are made on the parts, going around the outer contour of the sheet and near the pre-made holes.
Flanging is usually used to process the ends of pipes on which flanges are installed.
Usually a volumetric or cavity part is subjected to crimping processes - with its help, the parts acquire a narrowed end part.
This is done using a conical die using an external reduction of the sheet metal. When molding, the shape of the parts changes, keeping the shape of the outline on the outside.
It should be noted that most often volumetric stamping of metal products is made to order, because required necessary equipment, which cannot be done at home.
What do you need for stamping?
Sheet metal stamping technology requires special equipment: shears, crank press and Hydraulic Press having several washers and a matrix surface.
It is also necessary to comply with the norms of work and the calculation of the material.
For cold stamping, a hydraulic press is most often used. this equipment comes in a variety of designs and makes it possible to manufacture parts of different shapes with a decrease in material consumption.
Also, the choice of the press depends on the work that needs to be done with the workpiece.
For example, punching and punching requires a single-action press, which is characterized by a small stroke of the slide and washers, as well as a decrease in material consumption.
To produce a draw, you need a press that has a double action and a noticeably greater stroke of the slider and washers.
According to the design of the press, there are single-crank, double-crank, four-crank, but they all differ in the presence of a matrix.
The last two types are distinguished by larger trunks and sliders.
The press works due to the presence of a V-belt transmission: the movement is directly transmitted by means of a starting clutch and washers to the crank shaft.
With the help of a connecting rod capable of adjusting the length, the movement enters the slider and brings it into operation.
The slider moves in a reciprocating manner towards the table. The press is started by the pedal, which acts on the clutch. The pedal is installed on the press itself.
A four-rod pneumatic press with washers and a matrix punches out parts with a force, the center of which is between the connecting rods, which form a quadrangle between themselves.
Such a device is capable of making complex dies due to the off-center load on the slide. At the same time, there is practically no excess material consumption.
In this way, asymmetrical sheet metal parts can be produced with large dimensions with reduced material consumption.
To make more complex products, you need a pneumatic press that has a double or triple action, as well as a correct calculation.
The peculiarity of this equipment is that it is equipped with two or three sliders.
In a double-acting press, the outer slide clamping the metal workpiece by means of a buffer, and the slide inside allows the die product to be drawn.
First, the outer slider begins to move, after it reaches the lowest point, it freezes and fixes the edge of the part on the surface of the matrix.
Then the inner slider starts to move and the drawing process begins - all this time the outer slider remains in place.
After the work is completed, the second slider rises up, thereby freeing the workpiece on which the work is being done. Thus, a volumetric or other part is produced using a press.
For working with thin sheets of metal, there is a special friction press with washers, while hydraulic models are used mainly to create parts from thick sheet metal to reduce the possible consumption of material.
The hydraulic press is distinguished by a high quality of material stamping, due to the presence of more reliable washers, matrix and other elements.
It is used for most of the work associated with stamping sheet metal.
Another plus in its favor for use in production and with your own hands is that it does not undergo overload, which quite often happens while working on a crank press.
Not only a machine with a press is required for metal stamping. For correct work with a decrease in material consumption, a machine with built-in vibrating shears is also required.
In addition to scissors, the machine has short legs. The metalworking work begins with the upper knife, which is started by an electric motor.
When working, a sheet metal blank must be placed on the table, and slide it between the legs from above and below until it stops.
This type of metal processing is so popular because the amount of material consumption is reduced compared to other options for work.
Plus, with its help, a part of any kind can be created: volumetric, flat, cone-shaped, etc.
The calculation of the required material can be carried out both independently and with the help of specialists, but, in any case, the norms will be lower than with other metal processing.
For all its advantages, this metal processing requires special equipment: to work, you need a machine on which there is a press, a matrix surface, several washers and other elements, and it is also necessary to comply with the norms of work.
All this makes it difficult to create a machine with your own hands, however, ordering the manufacture of parts by stamping is not so expensive, therefore urgency to have a similar machine at home is absent.
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