Analysis of the cause of mold burst


1. The mold material is not good, and it is easy to chi […]

1. The mold material is not good, and it is easy to chip in the subsequent processing
2. Heat treatment: deformation due to improper quenching and tempering process
3. Insufficient grinding flatness of the mold causes bending deformation
4. Design process: insufficient mold strength, too close distance between blades, unreasonable mold structure, insufficient number of template blocks, no gaskets
5. Improper tangent processing: pull thread tangent, wrong gap, no clear corner
6. Selection of punching equipment: punching tonnage, insufficient punching force, excessive adjustment of the mold
7. Unsuccessful peeling: no demagnetization treatment before production, no back stitches; jammed materials during production, such as broken needles and broken springs
8. The blanking is not smooth: assembling the mold, rolling or blocking the feces, when the feet block the feces, there is no fecal leakage
9. Production awareness: laminated stamping, positioning is not in place, no blow gun is used, and the template is broken. There will still be mold failure modes. Mold failure modes are mainly wear failure, deformation failure, fracture failure and bite failure. However, due to different stamping processes and different working conditions, there are many factors that affect die life. The following is a comprehensive analysis of the factors affecting mold life in mold design, manufacturing and use, and corresponding improvement measures have been found

1. Stamping equipment The accuracy and stiffness of stamping equipment (such as presses) have an extremely important impact on the life of the mold. The stamping equipment has high precision, good rigidity and greatly improved die life. For example, the material of the composite silicon steel plate mold is Crl2MoV. When used on an ordinary open press, the average regrind life is 1-3 thousand times, and when used on a new precision press, the regrind life of the mold can reach 60,000 to 120,000 times. Especially for small or gapless punches, carbide punches and precision punches, a press with high precision and high rigidity must be selected. Otherwise, the life of the mold will be shortened, and the board will be damaged in severe cases.

2. Mold design (1) The accuracy of the mold guiding mechanism. Accurate and reliable guidance has a great influence on reducing the wear of mold working parts and avoiding damage to concave and convex molds, especially for blanking molds with no gaps and small gaps, composite molds and multi-station progressive molds. In order to improve the life of the mold, it is necessary to correctly select the guiding form and determine the accuracy of the guiding mechanism according to the nature of the process and the accuracy of the parts. Under normal circumstances, the accuracy of the guiding mechanism should be higher than the tip of the male and female molds.
(2) The geometric parameters of the cutting edge of the mold (convex and concave mold). The shape of the concave-convex mold, the fit gap and the fillet radius not only have a great influence on the forming of the stamping part, but also have a great influence on the wear and life of the mold. For example, the fit clearance of the mold directly affects the quality of the blanking parts and the life of the mold. In order to obtain higher accuracy requirements, a smaller gap value should be selected. Otherwise, the gap can be appropriately increased to increase the life of the mold.

3. Stamping process
(1) Raw materials of stamping parts.
In actual production, due to excessive thickness tolerances of the raw materials of external pressure parts, fluctuations in material properties, poor surface quality (such as rust) or dirt (such as oil stains), etc., will cause the wear and tear of mold processing to increase parts and Fragile easily. as a result of. Therefore, it should be noted: ① Try to use materials with good stamping processability to reduce stamping deformation force. ②Strictly check the grade, thickness and surface quality of the raw materials before stamping, and wipe the raw materials, and perform surface oxidation and rust removal if necessary; ③ According to the stamping process and the type of raw materials, softening treatment and surface treatment can be arranged when necessary, and select the appropriate Lubricants and lubrication processes.
(2) Layout and edges.
Unreasonable reciprocating feed layout method and too small overlap value usually cause rapid wear of the mold or damage to the convex and concave mold. Therefore, while considering the improvement of material judgment and utilization, it is necessary to reasonably choose the layout method and boundary value according to the processing batch of the parts, the quality requirements and the mold matching gap to improve the service life of the mold.

4. Mould material The influence of mould material on mould life is a comprehensive reflection of material types, chemical composition, organizational structure, hardness and metallurgical quality. Die life of different materials is often different. For this reason, two basic requirements are put forward for the material of the working parts of the die: ①The material's performance should have high hardness (58~64HRC) and high strength, and have high wear resistance and sufficient toughness. The thermal hardness; ②Good process performance. The processing and manufacturing process of die working parts is generally more complicated. Therefore, it must have adaptability to various processing techniques, such as forgeability, machinability, hardenability, hardenability, quenching crack sensitivity and grinding workability. Usually according to the material characteristics of the stamping parts, production batch size, precision requirements, etc., the mold material with excellent performance is selected, while taking into account its processability and economy.

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