The production of metal stamping parts is processed by punch press. Each punch press has a set of molds to process stamping parts of various shapes, because the molds need to calculate the tonnage, that is, to determine the size of the punch press. Prior to the design of each set of die, the tonnage needs to be calculated first to prevent incomplete die blanking due to insufficient tonnage. Let's learn the calculation principles:

The tonnage of punch is mainly related to the force required for stamping. Punching has punching shear force, and lifting also has lifting force. The tonnage is not enough and the lifting is not in place.

When selecting the punch, the punching force, unloading force, bending force and ejector force of the whole set of dies shall be added up and multiplied by the safety factor of 1.3. The tonnage of the selected punch shall be greater than or equal to this result to ensure rationality. Here is a formula:

F=LT σ bf

1. L refers to the length of the trimming line. For example, if you punch a square hole, its trimming line length is the sum of the four sides of the square hole, which is just its circumference.

2. T refers to the material thickness as above, and the unit is mm. F refers to the blanking coefficient, which is generally 1.3

3、 σ B refers to the tensile strength of steel plate material of stamping parts

The result obtained by multiplying the above is the punching pressure, but the unit is cattle. If you divide 9800 into tons, you will get the basic tonnage. Then, considering the safety margin of punching and the force required for other work such as unloading and pushing parts, divide this tonnage by 0.7 to get the tonnage of the machine tool.