Causes and solutions of common burr problems in metal stamping

Causes of common burr problems in metal stamping and solutions 1. Thick and high burrs are produced around the shear section. The collapse and inclination angles of the shear section are large, while the middle is obviously concave. The burrs are not only high, but also triangular in cross section, so do not use The file cannot be removed. Such stamping parts are generally defective products. Causes: (1) the gap is too large, (2) the verticality of the die decreases during multiple grinding, and for the full taper die, it is out of tolerance due to re-grinding. Solutions to reduce the gap: (1) Simple shape, small volume can be reworked (2) Stamping small and thin products can be processed by electric spark hardening; (3) Annealing the mold, repairing the blade, and then performing heat treatment and grinding , (4) Overlay welding repair treatment, (5) When pressing the inserts, the mold backing plate should be used, and the processing can be carried out after the blade is pressed out. Second, the height of the burr is too large or too small, and the height of the burr increases. Among them, the gap is too large, resulting in triangular burrs, the thickness increases, and the gap is too small, and the burrs are thin and high, resulting in secondary shear. Causes: (1) the gap is locally inconsistent, (2) the sag of the cutting edge causes local deviation' (3) due to the eccentricity of the mold, the burr height will be inconsistent with half, a. Mold installation is not good, b. The guide post is not well assembled (4) The guide post is loose. (5) The accuracy of the press is poor. Solution: (1) After deburring, when the shape of the shear section of the product is not flat, it is because the gap is partially too large or too small, so it needs to be corrected. (2) The cutting edge is locally worn, or due to poor quenching hardness, local collapse occurs, and the root of the burr increases, so grinding is required. (3) The punch and the die are not concentric. This is because half of the shear section is too large and half is too small. This is easy to understand. If it is the reason that the mold or the guide post is not well assembled, just adjust it. However, if the position of the mold core changes during each stroke, it is due to the loosening of the mold assembly part, and the mold core needs to be removed to tighten the correction port (4) due to the thrust force during punching, which will cause misalignment. When the side bearing block or the guide plate is stressed, in order to ensure the accuracy, the guide rail must be used. However, after the guide column is used, if the concentricity is not good, it is because of the poor quality of the guide column. (5) The press is not good. 3. Large burrs (compression burrs) appear on the shear section, which is called a compression burr, where there is an obvious tongue-like part on the shear section. Causes: (1) The overall gap is too small, and there is a collapsed corner or notch somewhere in the cutting edge of the die, (2) The back angle of the die appears inverted taper, (8) The die hole is difficult to finish machining, there are rough surfaces, and it is pressed. The high part of the cracked surface is broken. Solution: (1) Adjust the gap and sharpen the cutting edge. (2) Use a grinding wheel to remove the bright part of the back corner of the die caused by repeated collisions. (3) The vertical wall of the repair die hole touches the part with serious spots. Fourth, the shear section shows linear ribs. The so-called linear ribs are the phenomenon of convex or concave lines appearing on the shear section. Causes: (1) There is damage such as a nick or curling edge somewhere in the die, (2) due to improper or insufficient lubricant selection, causing ablation of the horizontal tool, (3) chip breaking or foreign matter mixed in and adhering to the mold. Solution: (1) The mold is stuck during the centering operation, or the mold is too hard to cause chipping or curling. The former is best to grind the seized part, while the latter is best to reduce the mold hardness, otherwise, chipping and curling will occur again. (2) If the blank is stuck in the mold due to heat generated during the stamping process, and the mold is scratched, the lubricant must be changed while using the back angle. (3) If defects are caused by shrinkage or foreign matter melting on the inner wall of the cavity, measures must be taken to prevent dirt from adhering to the blank. Previous post: Is stamping dangerous in the end? Why do people talk about stamping and discoloration?