What are the causes of unilateral burr in stamping parts?

The causes of single side burr in stamping parts are as follows:

 

Die assembly error. If the punch is not perpendicular to the fixed plate or is loose due to wear, or the locating pin is loose, the correct fixed position of the punch and die can not be guaranteed.

 

The guidance accuracy is poor. The center lines of the upper and lower dies do not coincide with each other due to the excessive fit clearance of the die guide parts, which affects the uniformity of the stamping gap.

 

Installation error. During the installation of the non guide die, the position of the upper and lower die is not allowed, resulting in uneven gap. The surface of the mould or the bottom plate is not clean, or the screw of the upper die is not tightened properly, which may cause the working part to tilt.

 

The die deforms when it works. For example, the leakage hole of punching mattress board is too large, the lower template of die is too thin, and the rigidity of female die is not enough.

 

The gap between the guide rail of punch press is too large, and the parallelism between the bottom surface of the slide block and the working table is not good, or the sliding direction of the slide block is not vertical to the working table.

 

When the maximum resistance of the workpiece is more than 80% of the nominal pressure of the punch press, the "C" shaped bed is easy to deform for the open punch, and the center lines of the upper and lower dies do not coincide.

 

Due to the poor flatness of sheet metal, the punch with smaller diameter is inclined in the process of metal stamping.

 

Due to improper material selection, forging and heat treatment, the die deforms during heat treatment or WEDM, which affects the uniformity of die gap.