Metal stamping parts is widely used in all areas of our life, including some electronic devices, automotive parts, decorative materials, etc. The stamping parts we usually refer to be cold stamping parts.

　　The measurement method of metal stamping parts: The hole measurement of metal stamping parts is based on the small-scale measurement method. Generally, small values ​​can be recorded when measuring with calipers (except for small values, such as measurement errors Error), (without excluding special cases) recording large values ​​has no practical significance with the average value, and the difference in the measured size of the aperture in all directions should be recorded in the circularity of the shape tolerance, not the aperture.

　　Also, if it is surveying and mapping, and there is no size to refer to, it should be determined according to the cross-section situation. It cannot be taken as the average value. For example, the small value measured may be caused by the wear of the punch somewhere. The light band are extremely small, so this small value is meaningless.

　　Generally speaking, the wear of the punch results in the reduction of the punching hole (special-shaped holes need specific analysis), so you can take a large value when mapping, and do not forget the quality of the section, because the basic size of the hole is taken when the punch is manufactured + The large value of the allowable deviation is multiplied by 0.5 to 0.75 to leave the amount of wear. After a period of use, the punching becomes smaller, but as long as the section quality is acceptable, its value is still within the tolerance range. At this time, the larger value is It is correct (for the same reason, excessive values ​​should be ruled out that there are factors such as warping of holes in the plate thickness direction, especially for thin plates)