Blanking or bending compound die structure: the punch (also called punch or punch) is designed in the lower die, and the other templates are the lower clamping plate (fixed punch), the lower stop plate and the lower stripper plate (outer stripper) in turn. The upper die consists of a female die (or knife edge), an inner stripper plate and an upper backing plate in turn. The inner stripping is hung on the upper backing plate with an equal-height sleeve, and then supported by a rod or a spring.
For the compound die for blanking, the internal demoulding of the female die is generally 0.50mm, which cannot be lower than that of the female die, otherwise the edge of the female die is easy to collapse or not demould. The internal separation force should be large enough to push the product out of the master mold. If the general material is thick, we have a nitrogen spring on it.
Compound die is a kind of die structure, which can be classified as engineering die because it is widely used in engineering die. Generally, a whole engineering die adopts compound die structure.
In general, the compound die structure is also adopted for the upward molding, upward bending, upward convex hull, upward convex point and upward warping of the continuous die.
★ Should the punch be higher than the stripper when punching the convex hull of the compound die?
Today, I received a question from a classmate, saying: When punching the convex hull of the compound die, should the punch be higher than the stripper?
The answer is yes, how to hit the convex hull if the stripper is not high?
It is suggested that this student review what compound die is again. How to calculate the punching length? After figuring this out, you will naturally understand how to answer this question.
When the compound die structure punches the convex shell, the length of the punch is equal to the thickness of the clamping plate+the thickness of the stop plate+the thickness of the stripper plate+the height of the convex shell.
That is, when punching, the punch must be higher than the stripper when the punch is killed. How much higher? Of course, how high the convex hull is, how high it is here, and it must be within the allowable accuracy required by the convex hull height.
When opening the mold, the mold is not subjected to any force, and the convex convex punch must be shorter than the stripper plate and retracted into the stripper plate, otherwise the stripper stroke will be increased.
When punching the convex hull of the compound die, when the die knocks down, the stripper must first press the material with sufficient pressure, and then punch the convex hull, otherwise the product may be deformed and the convex hull size will be unstable.
★ Materials and functions of stamping die template
General stamping die is made up of:
Upper and lower trays, upper and lower foot pads, upper and lower die holders: A3, Q235, etc. Generally used. Soft material? Made, it plays the role of supporting the whole mold and is convenient for mold loading and blanking.
Upper and lower templates: The upper and lower templates have the functions of fixing knife edges, inserts, pins and ejector pins, and the lower template is also fixed with external positioning, internal positioning and floating guide pins, dual-purpose pins, guide plates and floating blocks. The hardness of the lower template must be about HRC 58 ~ 62, and too low hardness will affect the blanking quality. The thickness is generally 25 ~ 40 mm, and some blades are cut directly on the template, that is, the blades are dug directly on the template. If the blade is missing, cracked, worn and burr, the mold is difficult to repair; Another way is to dig a block, that is, dig a knife edge on an insert (the insert is used to call? Lower die blade? ), and then put the lower die blade into the lower template. The height should be as high as that of the lower formwork, and the error should be within plus or minus 1 ~ 2, preferably within plus or minus 0.005mm, which can be achieved by the general grinder master or fitter master. Too much will print out the product (die printing).
The upper and lower pads are generally made of Cr 12. According to the needs, the thickness of the upper and lower pads of each set of molds is different. According to the punching strength, the upper and lower pads can be made thinner by 8 ~ 10 mm if there are few holes, and thicker if there are many holes, generally about17 ~ 20 mm. The lower pad mainly includes blanking holes, spring holes, screw holes, guide post air holes, etc.
It is mainly used to fix the upper and lower splints of punch, punch and guide post, generally 17 ~ 20mm. Generally speaking, the material hardness of the clamping plate of stamping die does not need to be particularly high, and generally soft materials can be used. Too soft is not good. It is possible to pull the platform of the punch directly into the splint, so that the splint is broken. Therefore, when designing the stamping die, we should consider the structure of the die, the material selection of the die, the tonnage of the selected punch and the size of the blanking gap. From the blanking of the workpiece to the president, the burr of the machined workpiece is smaller and the service life of the die is prolonged.
Baffle, stripper, etc. The baffle can be made of Cr 12, but the stripper must be made of hard materials such as Cr 12Mov. The baffle and stripper are locked together by M6 or M8 screws. There are mainly some through holes, punching holes and guide post holes above the baffle. The stripper plate mainly plays the role of stripping, pressing and guiding the punch. Generally, we use stripper to guide punch, guide pillar and punch. In the production of aluminum, it is easy for aluminium scrap to jump into the stripper to roughen the punch, or to jam the punch, pull off the punch and pull out the stripper, so it is necessary to use a stop to guide the punch and enlarge the stripper unilaterally 10 ~ 20 pieces; Or the stripper is two-stage, the upper stage is used for straightening, and the lower stage is also unilateral amplification 10 ~ 20. The thickness of the baffle is generally 8 ~ 17 mm, which is also determined according to the number of holes and the force to be applied. The thickness of stripper is generally 20 ~ 25mm.
Die and punch, also known as punch or knife edge, are used to wash away, cut off or cut, pierce and stretch excess materials. Such as: drawing punch, bending punch, slider insert knife, salad punch, convex bag punch, bud punch, riveting punch and so on. . The materials of the female die and the male die need higher hardness. Commonly used materials for female die and male die are: Cr 12Mo 1v 1, Cr 12Mov, Skd-5 1, SKD-1/and W6Mo5Cr4V2.
Explanation of technical terms:
Digging: used by modelers, it means to cut the opening of the frame. For example: digging a knife edge, digging a block, etc.
Soft material: In stamping die, it refers to die steel with hardness of about HRC35 and relatively low hardness, such as 45# steel, A3, Q235, etc. You can knock a hole with something a little harder. This material is so soft that people are used to calling it? Soft material? Because of its good seismic performance, it is generally used to make upper and lower trays, upper and lower pads and upper and lower die seats of stamping dies.
Hard material: in stamping dies, it refers to die steel materials with hardness (after heat treatment) of about HRC 58 ~ 62 or above, such as Cr 12, Cr 12Mo 1v 1, Cr 12Mov, SKD. These steels have high hardness (but they are also brittle, and you may break a piece if you are not careful, 55). They are generally used as cutting edges, punches or other parts that need high hardness.
★ Three views of stamping die
Three views on stamping die, do you understand? Whether it is working as a punching die fitter, designing punching dies, or CNC operation, CNC programming, grinding machines, milling machines, etc. As long as it is related to mechanical processing, you must have the ability to read drawings, which is essential. If you can't even read the drawings, how can you process the parts?
View: Geometric pattern obtained by observing an object from different directions.
For example, when an object is placed in front of you: