Precision punching can be called precision punching, but precision punching is not only for precision punching, precision punching can be divided into three forms!

1. There are three forms of precision blanking for the air cover of the strong blanking

The Ra value of the parts with strong blanking is 1.6 ~ 0.2, and the dimensional accuracy is up to IT6 ~ IT9.

Strong blanking blanking, one side clearance generally take material thickness of 0.5% ~ 2.5%.The size of the fillet is determined according to the properties and thickness of the material.Generally, R is 0.01 ~ 0.03mm.When t<3mm, R can be set as 0.05 ~ 0.1mm.Generally, (1.5 ~ 2) t should be used for edges, but not less than 1mm.

The blanking force, blanking force and back pressure can be calculated by the following formula.

P1= (1.3 ~ 1.5) Lt*

Pt= (0.3 ~ 0.6) P1

Pe= (0.1 ~ 0.15) P1

Among the above types, p1.pt.Pe is respectively blanking force, blank holder force and back pressure, and * is the shear strength of the material

2. Refurbished

Refurbishment is a process method of scraping off a thin layer of metal along the outer edge or inner hole of the blanking part by refurbishing die to obtain high-precision and low-roughness parts. After refurbishment, the dimension accuracy of the part can reach IT7 ~ IT8 surface roughness Ra value of 1.6 ~ 0.5.

3. Clean blanking

The difference between zhejiang textile machinery parts and ordinary blanking is that the radius of the round corner of the die edge is small and the clearance of the die is small.The punch is still in the ordinary form. The clearance between the two sides of the punch and concave die is smaller than 0.01 ~ 0.02mm.Commonly used small round corner concave die, the radius of the round corner generally take 10% ~ 20% of the thickness of the material.Smooth blanking is suitable for plastic material.The roughness Ra value of the part obtained by this method is 0.8 ~ 3.2, and the tolerance grade is IT9 ~ IT11.Smooth blanking required blanking force than ordinary blanking about 50%!