What is the accuracy level and defect level of automobile stamping parts?

Methods of turning over and twisting stamping parts:

• 1) In daily mold production, attention should be paid to maintaining the sharpness of the punching convex and concave mold edges. When the punching edge is worn, the tensile stress on the material will increase, so that the stamping parts tend to turn over and twist.
• 2) The unreasonable blanking gap or the uneven gap is also the reason for the turning and distortion of the stamping parts, which needs to be overcome.
• 3) Reasonable mold design. In the progressive die, the arrangement of the blanking sequence may affect the forming accuracy of the stamping parts. For the blanking of small parts of stamping parts, generally a larger area of ​​blanking is arranged first, and then a smaller area of ​​blanking is arranged to reduce the impact of blanking force on the forming of stamping parts.
• 4) Hold down the material. Overcome the traditional mold design structure, and open a material-holding gap on the unloading plate (that is, when the mold is closed, the material can be pressed. The key forming part, the unloading plate is made into a block-type structure to facilitate the long-term solution The wear (pressure) loss caused by the pressing part of the stripper plate caused by the stamping, and the material cannot be compressed.
• 5) Add strong pressure function. That is to increase the thickness of the pressing part of the unloading insert (the normal thickness of the unloading insert is H+0.03mm) to increase the pressure on the material on the side of the die, so that the stamping parts are turned over and distorted during punching.
• 6) The end of the punch edge is trimmed with a bevel or arc. This is the way to reduce the buffering force. Reducing the buffer cutting force can reduce the tensile force on the material on the die side, so as to achieve the effect of turning over and twisting the stamping parts.

Stamping defect level:

• Class A defects: defects that are unacceptable to customers, will cause stability complaints or cause stability hazards; surface defects and theoretical deviations have obvious deviations, which will attract the attention of untrained customers or cause functional failures. Such defective metal stamping parts It is unacceptable to the user, and the stamping parts need to be frozen immediately after discovery.
• Class B Defects: Unpleasant defects, usually complained about by users, cause general user dissatisfaction, and usually urge rework.
• Class C defects: Defects that need to be improved will cause claims (dissatisfaction) from discerning users. They are ambiguous and determined after careful inspection. Such defective stamping parts are repaired and repaired in B area, C and D areas. However, the repaired parts are not easy to be found by customers and need to meet the repairing standards of stamping parts.
• Class D Defects: Minor defects that may cause user dissatisfaction.