Solutions for crimping of punched holes and warping and distortion of stamping parts

First, the curling phenomenon that appears on the punched hole has different shapes due to different causes. (1) Curling due to uneven surface of the die. When the edge of the die is collapsed or notched, the above-mentioned defects will often occur when the die is punched in a recessed state after partial correction. It can be eliminated by improving the precision of the mold surface. (2) Crimping occurs due to improper design of the discharge plate. Because the gap between the discharge plate and the punch is too large, curling occurs. The measure is that the discharge plate must be close to the punch. In addition, even with this design, if the strength of the unloading plate is weak, the same phenomenon will often occur. (3) When bending and punching are performed at the same time, curling caused by stretching. When bending and punching are performed at the same time, curling tends to occur due to the hole being stretched into an oval shape. The measures are: either separate the two processes, or pay attention to the simultaneous progress of stamping and bending. (4) When bending, the guide hole is elliptical. When the hole guide is used for bending processing, the hole becomes elliptical due to stretching. The measure is to increase the pressure of the discharge plate or change the guiding method. Second, when stamping parts are of poor shape, stamping parts often have defects such as warpage and distortion. 1. Warpage (bending) The phenomenon that the stamped part is curved is called warpage (bending). Reasons and elimination methods (1) Due to the anisotropy of the material and the leveling of the coil at the end. Unloading plates, ejector rods, etc. can be used to press the material tightly before punching. When punching medium and thick plates, a cutting angle oblique blade die with a plate thickness of 1/3 to 1/4 of the shear stroke is used to achieve good results. (2) If the shear angle is designed to be too large or the shear angle is reasonably too small, the above defects will occur. Correct the shearing angle and appropriately increase the width of the sidewall to solve the problem. (3) When the ejector pin press pad is not designed on the mold structure, it needs to be corrected after punching. 2. The phenomenon of twisting the stamped part to be twisted is called twisting. Reasons and elimination methods: (1) When the strip material is cut, the product will inevitably show a twisted shape. The blanking die with ejector rod and discharge plate can be used to solve the problem. (2) However, even if the above blanking die is used, if the cutting angle of the oblique blade is too large, distortion will occur. The measure is to replace the press with a larger tonnage while reducing the shear angle. (3) If distortion occurs due to uneven clearance, the cutting edge needs to be corrected. (4) When it hits the back corner of the die and cannot uniformly blank the material, it is easy to be twisted. The measure is to observe the shear section and correct the back angle. Previous post: Causes and solutions of common burr problems in metal stamping