Stamping Machine


August 21, 2017 Facebook Twitter LinkedIn Google+ CNC Machine



Stamping is a method of forming a workpiece (stamping part) of a desired shape and size by applying an external force to a plate, a strip, a pipe, a profile, etc. by a press and a die to produce a plastic deformation or separation. Stamping and forging are the same plastic processing (or pressure processing), collectively forging. Stamping blanks are mainly hot and cold rolled steel and steel. The world’s steel, 60 to 70% of the plate, most of which finished by stamping. Car body, chassis, fuel tank, radiator film, boiler drum, container shell, motor, electrical iron core steel sheet are stamping processing. Instrumentation, household appliances, bicycles, office machinery, life utensils and other products, there are a large number of stamping parts.

Stamping processing is by means of conventional or special stamping equipment, power, so that the sheet material in the mold directly by the deformation force and deformation, to obtain a certain shape, size and performance of the product parts of the production technology. Sheet metal, mold and equipment are the three elements of stamping. According to the processing temperature is divided into hot stamping and cold stamping. The former is suitable for deformation of high resistance, poor plastic sheet processing; the latter at room temperature, is commonly used sheet metal stamping method. It is one of the main methods of metal plastic processing (or pressure processing), but also under the material forming engineering technology.

Stamping used by the mold called stamping die, referred to as die. Dies are special tools for batching materials (metal or nonmetal) into the required pieces. Punching in the stamping is essential, did not meet the requirements of the die, batch stamping production is difficult to carry out; no advanced die, advanced stamping process can not be achieved. Stamping process and mold, stamping equipment and stamping materials constitute the three elements of stamping, only they can be combined to get stamping parts.

Table of content

1. Processing characteristics

2. There is a problem

3. Solution

4. Process classification

4.1 Separation process

4.2 forming process

5.Material

6. Mold

7. Special equipment

8. Lubrication

9. Industry classification

10.Other references

11.List of Stamping Machine manufacturers

1. Processing characteristics

Stamping parts and castings, forging compared to a thin, uniform, light, strong features. Stamping can be made by other methods difficult to manufacture with a stiffener, ribs, undulating or flanging of the workpiece to improve its rigidity. As a result of precision molds, the workpiece accuracy of up to micron level, and repeat high precision, consistent specifications, you can punch out the hole nest, convex and so on. Cold stamping parts are generally no longer machined, or require only a small amount of cutting. Hot stamping parts accuracy and surface state is lower than the cold stamping parts, but still better than castings, forgings, cutting less.

Stamping is an efficient production method, the use of composite mold, especially the multi-station progressive die, in a press (single or multi-station) to complete the multi-stamping process, to achieve by the material open, Flat, blanking to the forming, finishing the automatic production. High production efficiency, good working conditions, low production costs, the general production of hundreds of pieces per minute. Compared with other methods of machining and plastic processing, stamping has many unique advantages both technically and economically. The main performance is as follows:

(1) stamping processing of high production efficiency, and easy to operate, easy to achieve mechanization and automation. This is because the stamping is to rely on die and stamping equipment to complete the processing, the average number of strokes per stroke up to dozens of times, high-speed pressure to hundreds of times per minute or even thousands of times, and each stroke May get a punch.

(2) stamping due to the mold to ensure that the stamping parts of the size and shape accuracy, and generally do not destroy the surface quality of stamping parts, and mold life is generally longer, so stamping quality and interchangeability, with “exactly the same” Characteristics.

(3) stamping can be processed to a larger size, the shape of the more complex parts, such as small watch to the stopwatch, large to the car longitudinal beam, cover, etc., plus stamping material cold deformation hardening effect, stamping strength and Stiffness are higher.

(4) stamping generally no chip scrap production, less material consumption, and no other heating equipment, which is a kind of material, energy-saving processing methods, stamping parts of the lower cost.

As the stamping has such a superiority, stamping processing in a wide range of applications in a wide range. For example, in the aerospace, aviation, military, machinery, agricultural machinery, electronics, information, railways, telecommunications, transportation, chemicals, medical equipment, household appliances and light industry and other departments have stamping processing. Not only the whole industry to use it, and everyone directly with the stamping product contact. Like aircraft, trains, cars, tractors, there are many large, medium and small stamping parts. Car body, frame and car ring and other parts are stamping out of the processing. According to the survey statistics, bicycles, sewing machines, watches are 80% of the stamping parts; TV, tape recorders, cameras, 90% of the stamping parts; there are food metal shell, steel boilers, enamel pots and stainless steel tableware, All the use of stamping die processing products; even the computer hardware is also the lack of stamping parts.

2. There is a problem

1, mold problems

Stamping processing used in the mold is generally dedicated, and sometimes a complex parts need to set a few sets of molds to shape, and the mold manufacturing of high precision, high technical requirements, is technology-intensive products. Therefore, only in the stamping parts production of large quantities, the advantages of stamping can be fully reflected, so as to obtain better economic benefits.

2, security issues

Stamping processing also has some problems and shortcomings. Mainly in the stamping process noise and vibration generated by the two kinds of pollution, and the operator’s security incidents have occurred. However, these problems are not entirely due to the stamping process and the mold itself, but mainly due to the traditional stamping equipment and backward manual operation caused. With the progress of science and technology, especially the development of computer technology, with the progress of mechatronics technology, these problems will be resolved as soon as possible and perfect.

3, high-strength steel stamping

Today’s high-strength steel, high-strength steel is very good to achieve the weight of the vehicle to improve the vehicle’s collision strength and safety performance, so become an important development direction of automotive steel. However, with the improvement of sheet strength, the traditional cold stamping process in the molding process is prone to rupture, can not meet the high-strength steel processing technology requirements. In the case of unable to meet the molding conditions, the current study of ultra-high strength steel sheet hot stamping technology. The technology is a new process which integrates forming, heat transfer and microstructure transformation. It mainly uses the technology of high temperature austenite to increase the plasticity of the sheet and reduce the yield strength.

3. Solution

In the past in the production of deep red or heavy punching workpieces, we all believe that pressure type (EP) lubricants is the best choice to protect the mold. Sulfur and chlorine EP additives are mixed into pure oil to improve the life of the mold has a long history. But with the emergence of new metal – high-strength steel, environmental requirements of the strict, EP oil-based oil value has been reduced, or even lose the market.

At high temperatures, high-strength steel molding, EP oil-based lubricants lost its performance, can not be used in extreme temperature applications to provide physical protection of the diaphragm. While the extremely warm type of IRMCO high solids polymer lubricant can provide the necessary protection. As the metal in the stamping die deformation, the temperature continues to rise, EP oil-based lubricants will be thinner, in some cases will reach the flash point or burn (smoke). IRMCO water-based stamping lubricant generally began to spray when the consistency is much lower. As the temperature increases during the forming process, it becomes thicker and more tough. In fact, the polymer polymer temperature lubricant has a “hot pursuit” and will stick to the metal, the formation of a friction can reduce the diaphragm. This protective barrier allows the workpiece to be extended and does not rupture and bond at the highest required workpiece to control friction and metal flow. Effectively protect the mold, extending the mold life, improve the strength of the stamping.

4. Process classification

Stamping is mainly classified according to process, can be divided into two major categories of separation process and forming process. The separation process, also known as blanking, is intended to separate the stamping part from the sheet along a certain contour line while ensuring the quality requirements of the separation section. The purpose of the forming process is to cause the sheet to undergo plastic deformation under non-crushing conditions to produce the desired shape and size of the workpiece. In the actual production, often a variety of processes integrated in a workpiece. Punching, bending, cutting, stretching, bulging, spinning, correction is several major stamping process.

4.1 Separation process

(Punch)

Is a basic stamping process using a mold separation material which can be made directly into flat parts or prepared for other stamping processes such as bending, drawing, forming, etc., or by cutting, trimming, etc. on the formed stamping parts The Blanking is widely used in industrial sectors such as automobiles, household appliances, electronics, instrumentation, machinery, railway, communications, chemical, light industry, textile and aerospace industries. Blanking processing accounts for about 50% to 60% of the total stamping process.

4.2 forming process

A plastic forming method of bending metal sheets, fittings and profiles at an angle, curvature and shape. Bending is one of the main processes widely used in the production of stamping parts. The bending of the metal material is essentially an elasto-plastic deformation process, after the unloading, the workpiece will produce the direction of elastic recovery deformation, called rebound. The effect of springback on the accuracy of the workpiece is the key to the bending process that must be considered.

Deep drawing is also known as drawing or rolling, is the use of mold blanking blanks obtained after the blank into the opening of the hollow parts of the stamping process. With the drawing process can be made of cylindrical, stepped, tapered, spherical, box-shaped and other irregular shape of the thin-walled parts. If combined with other stamping processes, parts that are extremely complex can be made. In the production of stamping, drawing a lot of types of pieces. Because of its different geometrical characteristics, the location of the deformation zone, the nature of deformation, the distribution of deformation and the stress state and distribution of various parts of the blank have a considerable and even essential difference. So the process parameters, process number and order to determine the method and mold design principles and methods are not the same. A variety of drawing parts according to the characteristics of deformation mechanics can be divided into straight wall rotator (cylindrical), straight wall non-rotating body (box body), curved surface (surface shape parts) and surface non-rotating body four Types of.

Drawing is through the drawing die on the sheet to exert tension, so that the sheet produced uneven tensile stress and tensile strain, with the sheet and the drawing die surface gradually extended until the drawing surface with the full fit. The application of the drawing is mainly made of plastic material with a certain plasticity, large surface area, curvature change and smooth, high quality requirements (shape accurate, smooth flow line, stable quality) of the double curvature of the skin. Drawing process because of the use of equipment and equipment is relatively simple, so low cost, flexibility; but the material utilization and productivity is low.

Spinning is a metal rotary processing technology. In the process of processing, the blank with the spinning die active rotation or spinning head around the blank and spinning die active rotation, rotating head relative to the core mold and blank for the feed movement, so that the continuous deformation of the blank to obtain the required hollow Body parts.

Shaping is the use of established shape of the shape of the product for the second trimming. Mainly reflected in the pressure plane, foot and so on. For some of the material there is flexibility, can not guarantee a molding quality, the use of re-processing.
The bulging is a method of drawing a thinner local surface area by means of a die to obtain a part. Commonly used undulating forming, cylindrical (or tubular) rough bulging and flat sheet rough drawing and so on. Bulge can be achieved using different methods, such as just die bulging, rubber bulging and hydraulic bulging and so on.

A method of bending a material that is bent along a curve or a straight line to bend the material in the narrow band area of ​​the preformed edge of the sheet or the blank. The flanging is mainly used for the edge of the part to strengthen, remove the trimming and the parts made with other parts of the assembly, the connection of parts or with complex shape, reasonable space of the three-dimensional parts, while improving the rigidity of parts. In the large sheet metal forming, but also as a means of controlling the rupture or wrinkles. So in the automotive, aviation, aerospace, electronics and household appliances and other industrial sectors have been very widely used.

The necking is a stamping method that reduces the diameter of the non-flange hollow or the open end of the tube. Shrinkage before and after the workpiece diameter changes should not be too large, or the end of the material will be due to compression deformation and wrinkle. Therefore, the larger diameter shrink into a very small diameter of the neck, often need to shrink many times.

5.Material

The surface and intrinsic properties of the stamping sheet have a great influence on the quality of the finished product. The requirements for stamping materials are:

① thickness accurate, uniform. Stamping die precision, small gap, the thickness of the board over the General Assembly to increase the deformation force, and cause card material, and even die die; sheet too thin will affect the quality of finished products, even in the deep drawing.

② surface smooth, no spots, no scars, no scratches, no surface cracks and so on. All surface defects will remain in the finished workpiece surface, crack defects in the bending, drawing, forming and other processes may be deep and wide expansion, resulting in waste.

③ yield strength uniform, no obvious direction. Anisotropy (see plastic deformation of the sheet in the drawing, flanging, bulging and other stamping process, due to the emergence of successive yield, plastic deformation is inconsistent, will cause uneven deformation, so that the formation is not accurate Defective or scrap.

④ uniform elongation is high. In the tensile test, the elongation before the specimen begins to appear in the neck is called the uniform elongation. In the deep drawing, the deformation of any area of ​​the sheet material can not exceed the uniform extension of the material, otherwise there will be uneven deformation.

⑤ yield ratio is low. The ratio of the yield limit and the strength limit of the material is called the yield ratio. The low yield ratio can not only reduce the deformation resistance, but also reduce the tendency to wrinkle when drawing deep, reduce the amount of rebound after bending, improve the accuracy of bending parts.

⑥ low work hardening. After the cold deformation of the work hardening will increase the deformation resistance of the material, so that the deformation difficult to continue, it is generally used low hardening index of the plate. But the hardening index of high plastic deformation of the material is good (that is, plastic deformation is more uniform), less prone to localized cracking.

In the actual production, commonly used with the stamping process similar to the process test, such as drawing performance test, bulging performance test materials such as stamping performance to ensure the finished product quality and high pass rate.

6. Mold

The precision and structure of the mold directly affect the forming and precision of the stamping parts. Mold manufacturing costs and life is the impact of stamping parts cost and quality of the important factors. Mold design and manufacturing need more time, which extends the production of new stamping parts of the preparation time. (For small batch production), composite mold, multi-station progressive die (for mass production), and the development of rapid mold changing device, can reduce the amount of stamping production preparation work (for mass production), mold, And shorten the preparation time, can be applied to mass production of advanced stamping technology reasonably applied to small quantities and more varieties of production.

7. Special equipment

In addition to thick plate with hydraulic press forming, the general use of mechanical presses. With the modern high-speed multi-station mechanical press as the center, equipped with open-book, flattening, finished product collection, transportation and other machinery and mold library and rapid mold change device, and the use of computer program control, can form a high productivity automatic stamping production line.

8. Lubrication

General work in the stamping process, due to the stamping process, especially in the cold forging process, the temperature will rise quickly, must be added lubricating oil lubrication, if not using lubrication and direct stamping, in addition to the workpiece finish is affected, Mold life will be shortened, while the accuracy is reduced, for this improvement in the mold will put a lot of costs. It is for this reason, so in the cold forging stamping must be stamping lubrication.

9. Industry classification

Press the drive structure:

Manual punching machine: manual, low efficiency, low pressure, suitable for small holes, paper, leather and other manual processing.

Mechanical punch: mechanical transmission, high speed, high efficiency, tonnage, the most common.

Hydraulic press: hydraulic drive, the speed is slower than the mechanical, tonnage, the price is cheaper than the mechanical, very common.

Pneumatic punch: Pneumatic transmission, and hydraulic equivalent, but the stability of hydraulic, usually less common.

High-speed mechanical punch: mainly used for electronic products such as continuous die blanking, such as the motor set, the rotor film, CNC, high speed, to the general mechanical punch about 100 times. common.

There is also a CNC punch, this punch is relatively special, mainly for processing more holes and distribution of dense parts.

According to the processing accuracy:

Ordinary punch
Precision punch

By use:
Ordinary punch
Special punch: such as punching machine

10.Other references

Mould Design
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CNC Turning Machine
Universal Milling Machine
Horizontal Milling Machine
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Tapping Machine
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ERP – Enterprise Resource Planning
CAM – Computer Aided Manufacturing
CAD(Computer Aided Design)
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3d-printer
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11.List of Stamping Machine manufacturers

Queensland Metal Spinners
Australian manufacturer of metal spinning, metal stamping, plasma cutting and deep draw pressing.

Narmco Group
Canadian manufacturer of metal stampings, roll forming, assemblies.

Jancox Stampings
Canadian contract manufacturer of metal stamping parts, welded assemblies, mechanical assemblies for automotive industry.

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