【正文】 piece is also easy to scratch mold. Bad cold stamping plastic materials, deformation is small, easy to press when the workpiece rupture, but also easy to scratch mold. In addition, the material thickness tolerances shall ply with national standards. Die because of a certain thickness of material suitable for forming, bending, flanging, drawing die of the male and female die structure gap is directly determined by the thickness of the material. Therefore, uneven thickness, will result in waste generation and mold damage.2. Die Die Life ofDie Die Life of a mold material properties, chemical position, structure, hardness and prehensive reflection of metallurgical quality. Among them, the material properties and heat treatment affect the quality of the most obvious.Mold material properties on the impact of die life is great. If the same workpiece, using a different mold material of the bending test, the test results: The 9Mn2V material, the life of 5 million。 with Crl2MoV nitriding, the life of up to 40 million. Therefore, the choice of materials, the batch size should be based on workpiece, rational use of mold materials. The hardness of the die parts to Die Life a great impact. But not the higher hardness, longer die life. This is because the hardness and strength, toughness and abrasion resistance are closely related. Some die demands of high hardness, long life. Such as the use of T10 steel dies, hardness 54 ~ 58HRC, only washed thousands of times a burr on the workpiece great. If the hardness to 60 ~ 64HRC, the grinding life of up to 2 to 3 million. However, if continue to improve hardness, fracture occurs earlier. Some die hardness should not be too high, as the die manufacturing using Crl2MoV 58 ~ 62HRC hardness, the general life of 23 million, invalid form of chipping and cracking, and if the hardness down to 54 ~ 58HRC, life expectancy increased to 5 ~ 60 000, but decreased to 50 ~ 53HRC hardness appears easy to blunt the die edge phenomenon. Thus, mold hardness must be based on material properties and failure modes may be. Should enable the hardness, strength, toughness and wear resistance, resistance to fatigue strength needed to achieve a particular stamping process the best match.3. The surface of the mold heat treatment to strengthen the quality and impact on lifeMold heat treatment the nature and quality of life of the mold a great impact. Practice shows that the die parts of the quenching distortion and cracking, early fracture during use, while the metallurgical and materials quality, forging quality, mold structure and process related, but related more to die of heat treatment. According to statistical analysis of failure causes of mold, heat treatment failure due to improper accounting for more than 50%. Practice shows that the mold material must be acpanied by high heat treatment process properly, can really play a material39。s potential. Parts surface hardening mold work purpose is to obtain the effect of external hard tough inside, so be hardness, wear resistance, toughness, good resistance to fatigue with. Many ways to die surface hardening, surface treatment technology of new technologies developed rapidly. In addition to Nitrocarburizing and ion nitride, boride, seepage niobium, vanadium permeability, hard chrome plated and spark strengthening, the chemical vapor deposition (CVD) and physical vapor deposition (PVD) has been gradually adopted. By CVD and PVD treatment, the mold surface covered with superhard material, such as TiC, TiN, etc.. High hardness, wear resistance, corrosion resistance, adhesion is very good, can improve the die life several times to several times.4. Manufacturing precision of the die parts of die lifePrecision die manufacturing and life in it in particular, mold surface roughness on the mold a great impact. If using Crl2MoV steel blanking die, if the surface roughness value R = m, its life span is about 30,000. Such as polished by the precision, surface roughness value R = m, life can be increased to 45 million. Therefore, the working parts of the mold surface, the general must go through grinding, grinding, polishing and other finishing and fine processing.5. Other aspects of the impact of die life(1) Press the accuracy is not high, but also easy to make die damage.(2) die in the press or not installed properly and the operator39。s technical level, on the tool life is also greatly affected.(3) dies in the custody and maintenance of good and bad, and the use of lubricant condition also affects mold life.6. ConclusionIn actual production, sheet metal dies for use, rare case of nonnormal wear and tear. But when the die plate was found prone to irregular wear, we always study for the problems summarized. Because of a cold die, from the design, manufacture, assembly, missioning and installation and use, all spent many hours, while the convex die, die material used, mostly highquality alloy steel. Therefore, the die cost is relatively high. Therefore, in the production of understanding the factors that affect the die life and take the appropriate measures to guide the production of great practical significance. 30 / 30