# How to determine the tonnage of the punch for processing metal stamping parts

Release time:

2023-02-02

How to choose the punch tonnage for processing metal stamping parts? Each punch has a set of molds to process the various shapes of stamping parts, because the molds need to calculate the tonnage, that is, to determine the size of the punch. Each set of mold in the design of the need to give priority to the calculation of tonnage to prevent the lack of tonnage caused by incomplete die. Now let's look at how it works.

Punching tonnage is mainly related to the force required to punch. Punching has punching force, drawing also has drawing force, if the tonnage is not enough, drawing is not in place.

When selecting the punch press, the punch force, unloading force, bending force and rod push force of the whole mold should be added together, and then multiplied by the safety factor of 1.3. The tonnage of the punch selected should be greater than or equal to this result to ensure reasonable results. Here's a formula.

F = LT sigma bf

1. L refers to the length of the cutting line. For example, if you make a square hole, the length of the cutting line is the combined length of the four sides of the square hole, which is just the circumference of the hole.

2. T refers to the thickness of the material in millimeters, as mentioned above, and f is the punch factor, usually 1.3.

3. Sigma b refers to the tensile strength of stamped steel.

The result of the above multiplication is the punching force, but the unit is Nm. Converted into tonnage divided by 9800, it is the basic tonnage. After considering the safety factor of punching and the force required by unloading parts and jacking, the tonnage divided by 0.7 is the tonnage of the machine tool

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