Experimental Study of Shearing Dimensional Parameters in the Sheet Metal Blanking Process of StW24 Steel with a Thickness of 12 mm

Abstract

Blanking is a sheet metal cutting process, which itself is a prerequisite for many other forming processes. Punch and matrix shape and material, punch force and speed, lubricant, corner radius, and punch-matrix clearance are important variables in blanking. Clearance is critical in this process, depending on the material and sheet thickness, and is usually a percentage of the sheet thickness. Too much clearance causes the sheet to press and pull into the clearance area and Low clearance causes misaligned fracture lines and secondary cutting. Producing blanking with high thicknesses is always one of the challenges of the sheet metal blanking process. This study aims to create 57.5 mm diameter StW24 steel blanks with 12 mm thickness and a 38% penetration value. A blanking die was designed and built with different punches based on clearance values of 9, 15, and 21% to match the target drawing. Results show that increasing clearance from 9 to 15% leads to an 11% thicker rollover zone, 5% thicker fracture zone, and 33% thinner shear zone. Increasing clearance from 15 to 21% reduces the thickness of rollover, fracture, and shear zones by 24, 3, and 56% respectively. Increasing clearance from 9 to 21% also leads to a 51% increase in fracture angle and a 34% increase in burr size. Clearance of 15% of sheet thickness is best for producing blank as per the target drawing.