Punching Accuracy in the Case of Square-Shaped Holes

Currently, some parts made from workpieces in the form of sheets or strips are obtained by applying piercing processes. In the research whose results are presented in the article, square-shaped holes were made to evaluate the piercing accuracy of the surfaces generated by piercing in sheets of three different metal materials (carbon steel 1.033, aluminum alloy AlMg3, and stainless steel X5CrNi18-10) with different thicknesses. Apart from the nature of the material, the thickness of the sheet, the size of the clearance between the puncher and the die, and the average speed of the puncher were considered as input factors in the piercing process. The output parameters tracked were the size of the side of the square-shaped hole and the height of the burr generated by the cut. The experimental results were mathematically processed using special software, obtaining empirical mathematical models that highlight the influence of the input factors considered on the deviation of the side size of the square-shaped hole and the burr height. The analysis of the results showed that the intended size of the square hole side exerts the strongest influence on the piercing accuracy. The factor with the most significant influence on the height of the burr is the clearance between the puncher and the die.