What is the impact of the loosening of metal stamping die pins on the stamping parts? What is the reason for the loosening of the pins?

What is the impact of pin loosening in the structure of the metal stamping die on the quality of the stamping parts? What is the reason for the pin loosening? First, the metal stamping die usually uses pins as accurately positioned parts. If the pins are loose, the metal stamping parts will be damaged. Quality has a very big impact. These effects are mainly reflected in two aspects: 1) Loose pins cannot ensure that the upper and lower dies of the stamping die are concentric, and the uniformity of the gap between the convex and concave dies cannot be guaranteed. This causes burrs on one side of metal stamping parts; local wall thicknesses of bent parts, deep-drawn parts and back-extruded parts become thinner, and even ruptures may occur in severe cases. 2) The loosening of the pin causes the positioning device to move, which makes the positioning of the metal stamping parts unreliable, causing the stamping parts to produce waste due to the reduction of the edge value. The part is severely uneven, and the flange part of the deep-drawn part with flange is out of tolerance, and even breaks due to it. Second, the fit between the pin and the pin hole should generally be a H7/h6 fit, and there are four main reasons for the looseness: ① The fit between the pin and the pin hole does not reach H7/h6. ②The pin has not been heat-treated and has low hardness. ③The pin has not been ground or the pin hole is not round without reaming, grinding, etc., resulting in a reduction in the mating contact area. ④ Disassemble frequently. Previous post: What is the cause of the punch falling off during the stamping process?