The single-side gap of the die is 10%-20% of the thickness of the steel plate. Choosing a die with a small gap will produce small burrs during processing, but the life of the concave die will be short. A die with a large gap will easily produce burrs, but the concave die will be more durable.

Punching is a process of forming holes by gravity punching. The process is simple and generally does not have high requirements on the roughness and burrs of the workpiece. For example: processing 80*80*8mm angle steel, the workpiece thickness is 8mm, and the single-side gap of the die can be 0.8-1.6mm. If the customer does not want burrs to be produced during the processing, they can choose a concave die with a gap of 0.8mm on one side. The effect is good and there are no burrs, but the service life is relatively short. If you have no requirements for burrs, you can choose a die with a single side of 0.8-1.6mm. Burrs will appear, but they will be more durable.

How to determine the gap from the concave die diameter:

If the plate thickness is 8mm, the punch diameter is φ14, and the concave die diameter is φ15.6, then the unilateral gap of the die is (15.6-14)/2=0.8mm. On the contrary, if the single-side gap of the die and the diameter of the punch are known, the diameter of the concave die can also be calculated. In the figure, d is the diameter of the die, and the corresponding steel plate thicknesses are 5, 7, and 8mm respectively. It can be calculated that the unilateral gaps of the die are 0.5, 0.7, and 0.8mm, which are all 10% of the steel plate thickness. Therefore, this kind of die produces less burrs. But it is not as durable as a die with a larger gap.

Reasons for burrs during processing:

1. The gap between the die and die is too large.

2. The punch has been used too many times and needs to be replaced.