The pressure of the Roewe Car punch causes the material to undergo elastic compression, bending, drawing and other deformations, and is slightly squeezed into the concave mold hole. At this time, the material under the punch of the Roewe Car is slightly arched, and the material on the concave mold is slightly upturned. The larger the gap, the more serious the arching and upturning. At this stage, because the stress inside the material does not exceed the elastic limit , in a state of elastic deformation. When the Petrol Car punch is unloaded, the material returns to its original shape;
As the Roewe Car punch continues to press down, the stress in the material reaches the yield strength, and the material begins to produce plastic shear deformation; the Roewe Car punch squeezes into the sheet, and the sheet squeezes into the concave mold, forming a bright shear section, and at the same time due to the convex and concave There is a gap in the mold, so it is accompanied by bending and drawing deformation of the material (the larger the gap, the greater the deformation). As the punch of the Petrol Car continues to be pressed in, the deformation resistance of the material continues to increase, the hardening intensifies, and stress concentration occurs near the cutting edge. When the tensile strength of the material is reached, the plastic deformation stage ends;
3. Fracture and separation stage
When the stress near the cutting edge reaches the material failure stress, the material between the convex and concave molds successively generates cracks on the side of the cutting edge of the concave and Roewe Car convex molds, and expands toward the inner layer of the material along the direction of high shear stress, causing the material to separate.