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★The concept of stamping dies
Stamping dies, also known as die, metal mold, metal stamping dies, mean almost the same. It refers to a pressure processing method that uses a mold fixed on a punch press or a press to apply a certain pressure to a metal or non-metal plate to separate or shape the material, thereby obtaining a part with a certain size requirement and an appearance quality. There are many kinds of molds, and I mainly focus on the metal stamping parts molds that I am familiar with.
The products processed by the mold are basically the same in size and appearance. There is no big difference because of rapid molding, high production efficiency, stable product quality, accurate accuracy, high material utilization rate, simple operation and low labor intensity. The technical requirements of the operators are not high. As long as the general people come in and follow others for a day or two, they will be able to get started soon, and some even can learn in a few minutes without a day or two. If you are engaged in work, you must learn to operate the punching and blanking machine, the feeding machine, the leveling machine, the mold removal frame, etc., all of which are very simple, strong, and willing to work hard。
Usually pay attention to safety, do not put anything inside the mold, wrenches, scissors, other tools, etc. Do not put in the mold, after repairing the mold, you must be optimistic before you hit, see if they have forgotten things in the mold Inside, of course, generally do not make such mistakes, but you should also pay attention. Don’t break the mold, or hurt your body. Dry it and pay attention to safety. If you accidentally forget the mold, you can forget it. If you punch it, you may break the mold. In case something inside. If you fly out? People may also get hurt.
Sometimes when the forklift fork molds, the forks are not good, the molds fall down. At this time, don’t use your hands to help, let the distance be a little, the molds are broken, nothing to do, don’t take people to the wrong place; Be careful to stay away from the mold, and it is not good to watch the mold sway and touch it.
It is often easy to get into the mold or to deal with the mold. Newcomers should pay special attention to these safety issues when entering the factory.
★Structure introduction of stamping die
The structure of the stamping die, the structure of the die, the die structure are similar, the corresponding die is designed according to different product characteristics and requirements, the different die structure, its function is also different, the products produced are different, in general, it is simple , there are complex ones. But no matter how complicated the structure is, its basic structure is unchanged, nothing more than a number of templates, blocks and standard parts.
Molds are typically assembled from a number of stencils and parts (which we call block-in or entanglements) as well as standard parts.
The general stamping die structure, the specific template from top to bottom (including the code number) is:
The template for the upper mold is:
Upper pallet, upper footing, upper die base (UPU), upper backing plate (UBU), upper clamping plate (PHU) stop baffle (PPS), stripping plate (PSU);
The template for the lower die is:
Lower template (DIE), lower pad (LBD), lower die holder (LPD), lower pad, lower pad;
Other less common templates:
Upper cover plate (CVU), knockout plate, upper template, lower stripper plate, lower stop plate, lower plate, male mold, master mold, etc.;
Some mold parts are:
The entry of the upper mold, into the block: the plywood into the block, the stripping plate into the block, the punch, etc.;
The entry of the lower die, into the block: the lower die into the block, the lower die edge, etc.;
Standard parts: spring, hexagonal screw, stop screw, wire spring, contour set, guide post, guide sleeve, contour sleeve, dual-purpose pin, top pin, etc.
Non-standard parts: external positioning, internal positioning, pitch positioning, outer limit column, inner limit column, etc.;
★ stamping die number
Stamping die number, generally written like this (for example):
Engineering model: 90-KNMF0125RAH, 90-KNMF0125RAA, 90-KNMF0125RBB
Continuous mode: 90-KNMF0125SAA, 90-KNMF0125SBB
The latter RAH, R stands for engineering mode, H stands for a total of eight sets (from AH, RAH, RBH…RHH respectively), A stands for the first set; RAA or RBB stands for riveting molds, such as riveted studs, riveted shrapnel Wait;
The SA in SAA and SBB represents the continuous mode, 0125 represents the mold number, the front F represents the year, and the mold produced in which year is indicated by the number of the year, such as: F0125, G0125, if F represents 2010 Then, the mold F0125 produced in 2010 can be referred to as: 125 mold, and the next mold produced in 2011 is the beginning of G. At this time, you will say 125 molds, and most of them think it is G0125 mold.
Others such as the upper splint (PHU), the number is 90-KNMF0125SAAPHU, the splint into the block 90-KNMF0125SAAPHPA001;
If there are two segments in this continuous mode, use A and B to indicate after the 90-KNMF0125SAAPHU number, then the first segment of the splint should be 90-KNMF0125SAAPHUA, the second segment 90-KNMF0125SAAPHUB, the splint into the block 90-KNMF0125SAAPHPA001, 90 -KNMF0125SAAPHPB001;
Lower template (DIE): 90-KNMF0125SAADIE, 90-KNMF0125RAHDIE
Regarding the other numbers, there is no explanation here. Simply explain:
A complete stamping die structure from top to bottom should be:
No. Chinese name No. Chinese name M: Milling machine U1U Upper plate UDE Upper plate G: Grinder U2U Upper foot PS2 Lower stripping plate GD: Large grinding machine UPU Upper mold base PH2 Lower splint WC: Wire cutting UBU Upper pad? PUN punch W/E: Discharge PHU Upper splint PHP splint into block Y: Outward PPS stop baffle UDP Upper formwork block HT: Heat treated PSU Stripper plate PSP Stripper plate into block L: Lathe AXD Upper template into block D: Rocker arm Drilling machine DIE lower template DPI lower mold block LBD lower back plate – – LPD lower mold base – – B2D lower foot – – B1D lower support plate – –
The replacement of “-” indicates that this number is not common or rarely used.
★ Common materials for stamping and selection
The nature of the materials used in stamping is closely related to the stamping production. Its properties directly affect the stamping process design, stamping quality and product service life, as well as the organization of balanced production and stamping parts production costs.
When selecting the material of the stamping, it is necessary to consider not only the performance but also the stamping and subsequent process performance requirements. The basic requirements for stamping processing are as follows.
1, with good stamping performance
For the forming process, such as stretching, bending, stepping, convex hull, etc., the material should have good stamping and forming properties, that is, it should have good crack resistance, good moldability and shape, otherwise the product is prone to deformation. , rupture, etc., causing difficulties in repairing the mold. For the separation process, the material is required to have a certain plasticity.
2, with a high surface quality
The surface of the material should be smooth and flat without damage. The material with good surface quality is not easy to be broken during molding, and it is not easy to scratch the mold, and the surface quality of the workpiece is also good.
3. The thickness tolerance of the material should conform to the national standard.
Because a certain mold gap is only suitable for materials with a certain thickness range, if the material thickness tolerance is too large; not only directly affects the quality of the workpiece, but also may lead to the appearance of waste. In the process of correcting bending, shaping, etc., there is a possibility that the mold or the press is damaged due to excessive thickness deviation.
Common materials for stamping and selection
1. Common materials for stamping
The most commonly used materials in stamping production are metallic materials (including ferrous and non-ferrous metals), but sometimes non-metallic materials. Among them, ferrous metals mainly include ordinary carbon structural steel, high-quality carbon structural steel, alloy structural steel, carbon tool steel, stainless steel, electrical silicon steel, etc.; non-ferrous metals are mainly pure copper, brass, bronze, aluminum, etc.; non-metallic materials There are cardboard, laminate, rubber sheet, plastic sheet, fiberboard and mica.
The supply state of metal materials for stamping is generally various types of sheets and strips. The sheet material can be used for the production of engineering molds, and the strip material (rolling material) can be used for the production of continuous molds, and can also be used for the production of engineering molds. The size of the sheet material is large, and it can be used for stamping large parts. It can also be used for stamping small and medium-sized parts after cutting the sheet material into strips. The strip material (also known as coil material) has various widths. The unfolding length can be up to several tens of meters, and it is supplied in a roll shape, which is suitable for automatic feeding of continuous mold mass production.
For the grades, specifications and performance of various materials, please refer to the relevant manuals and standards.
- Reasonable selection of stamping materials
The selection of stamping materials should consider the use requirements of stamping parts, stamping process requirements and economy.
(1) Reasonable material selection according to the requirements of the use of stamping parts
The material selected should be such that the stamped part works properly in the machine or component and has a certain service life. To this end, the selected materials should meet the requirements of the corresponding strength, stiffness, toughness, corrosion resistance and heat resistance according to the conditions of use of the stamping parts.
(2) Reasonable material selection according to the requirements of stamping process
For any type of stamping, the material selected should be able to stably form a qualified product that does not crack or wrinkle according to the requirements of its stamping process. This is the most basic and important material selection requirement. To this end, the following methods can be used to select materials.
1 test. According to the previous production experience and possible conditions, several kinds of sheets that can basically meet the requirements for the use of stamping parts are selected for trial-and-shoot, and finally one which has no scrap rate or low wrinkle is selected. The result of this method is relatively straightforward, but with greater blindness.
2 analysis and comparison. On the basis of analyzing the deformation properties of stamping, the maximum degree of deformation during stamping is compared with the limit deformation allowed by sheet metal forming performance, and based on this, the board suitable for the stamping process requirements of the parts is selected. .
In addition, the same grade or plate of the same thickness, there are cold rolling and hot rolling. Among the domestically produced plates, thick plates (t>4mm) are hot-rolled plates and thin plates (t<>
The surface defects are small, the light is bright, the internal structure is dense, and the punching performance is better. (Note: t generally represents the thickness in the mold. For example, the thickness of the template and the thickness of the material can be expressed by t.)
(3) Reasonable material selection according to economic requirements
The selected materials should be as low-cost, convenient, and economical as possible to meet the requirements of use performance and stamping process, so as to reduce the cost of stamping parts.
★ Classification of stamping dies
The classification of stamping dies, generally we can simply divide it into two types, namely engineering molds and continuous molds;
The engineering mold can be divided into composite mold, tensile mold, riveting mold, etc. The structure and function of these molds are briefly introduced below;
Engineering mold: Also known as “single-process mold”, it refers to a mold that can only complete one stamping process in one stroke of stamping. After the project is finished, it is necessary to take the product out of the mold manually or with a robot, and then put it into the mold of the next station to continue production until the last process of the mold is finished, and the whole product is completed. The mold is simple to repair, but it takes time and labor to produce, requires a lot of labor and time costs, and has a high product scrap rate.
Composite mold: Common composite mold structure has composite blanking, composite stretching, etc. This mold structure is slightly different from other engineering mold structures. The punch is designed in the lower die, and the other templates are the lower clamp (fixed punch), the lower stop and the lower strip (outer). The upper die is the master (or knife) and the inner die. The plate and the upper pad are formed, and the inner sleeve is hung on the upper pad using a contour sleeve, and then is pressed by a rod or a spring. For example, the composite mold used for blanking can be removed from the master mold by 0.50 mm, and can not be lower than the master mold. Otherwise, the die edge of the master mold is easy to collapse or not take off. The force of the inner strip should be large enough to push the product out of the mother mold. Generally, if the material is thick, we have a nitrogen gas spring.
Continuous mode: Also known as “grading die”, it refers to the mold that completes two or more stamping processes at different stations at the same time during the one stroke of stamping. This kind of mold maintenance is difficult and requires experience. The rich fitter masters operate, but the production is very efficient. If you play fast, you can produce thousands of products in one hour, saving labor and time costs, and the product scrap rate is low.
★Spring compression and calculation
In a set of stamping dies, more elastic materials are needed, including various springs, superior rubber, and nitrogen springs. Different elastic materials are used according to different needs. For example, bending and punching can be done with ordinary flat springs, such as brown springs, also known as brown springs; if the power is not enough, add a nitrogen spring, of course, the cost is higher; superior glue is generally used for drawing molds. , plastic mold, or flatness.
The deep drawing mold is very good with the excellent glue, of course, you can also choose the nitrogen spring. Others such as top pins, floats, dual-purpose pins, etc. generally use wire springs or yellow springs, as long as they can be stripped off, do not push the product out of the print, the top deformation is good. The characteristic of Youli Gum is that the strength is relatively balanced. However, its life is relatively short. It may be cracked, not used, and wilted after a period of production. Therefore, it is generally used less often, and nitrogen springs are usually used. The whole flatness is used for a lot of glue.
The spring includes a flat wire spring, a wire spring, etc. The purpose of the spring is to remove the material and press the material, and the magnitude of the spring force is related to whether the mold production is smooth or not, and whether the product is qualified or not. The spring force is small, which may cause various problems such as product deformation, mold not to be stripped, products not good to be taken out from the mold, strips, knife edges, and punches.
Flat wire springs are generally divided into two colors: brown, green, red, blue, and yellow. The strength is also weakened in turn. The colors are different, the strength is different, and the compression is different.
There is a soil method to calculate the compression of the spring. That is, I just entered the factory to learn the mold soon. I don’t know much about the mold. My master taught me: measure the total height of the spring beforehand, and put the spring in the vise. , lock, and then use a caliper to measure the length of the spring after the clip is clamped, then subtract the total length from the spring, and then divide by the total length. This method is universal for any spring, such as the length of the brown spring is 60mm. After being clamped by a vise, there should be about 45.6 left, then you subtract 60 from 45.6 to 14.4, and then divide 14.4 with 60. The result is equal to 0.24, which is the amount of compression.
According to different production times, such as 1 million times, 500,000 times, 300,000 times, the larger the compression amount, the shorter the spring life, the shorter the life of the mold (of course, the spring can be replaced if it is broken), the mold After a period of production, the spring may be weak, and the spring with a poor quality may break in the mold. Generally, the compression amount of the spring is calculated according to 300,000 times, that is to say, the mold may be incapable of hitting 300,000 times of springs. Of course, the general stamping die life is not so long, and it can also be calculated according to the maximum compression amount, according to the maximum compression. If the amount is calculated, it can only guarantee that the spring does not explode inside the mold. The mold is pressed a little and it is good for product flatness.
The specific compression amount is as follows:
Color 100 times 500,000 times 300,000 times Maximum compression brown spring 16% 18% 20% 24% Green spring 19.20% 21.60% 24% 28% Red spring 25.60% 28.80% 32% 38% Blue spring 32% 36% 40 % 48% yellow spring 40% 45% 50% 58%
The maximum compression (how much this spring can be pressed), the maximum compression of the spring is equal to the free height of the spring multiplied by the maximum compression ratio of the spring, such as a brown spring, the length is 60mm, then its maximum compression is: 60 * 24% About 14, this spring can be pressed down to 14 mm, its maximum stroke is 14 mm, the stroke of the mold must be less than 14 mm, more than 14 mm, the spring may fail, deform, and possibly hit Broken in the mold, or the mold is explosive, the press can not be pressed and so on.
Before the mold is assembled, that is, before the mold is installed, it is necessary to calculate whether the compression amount of the spring is appropriate, so that when the mold is tested, there is no need to worry that the mold will have problems or explosions.
If you still have a place that you don’t understand or understand for this article, welcome comments or private letters, I will answer the first time!