How can plastic mold processing reduce defects?
1.Reasonably use cooling and lubricating fluid, give play to the three functions of cooling, washing and lubrication, and keep the cooling and lubrication clean, so as to control the grinding heat within the allowable range, so as to prevent the thermal deformation of the workpiece. Improve the cooling conditions during grinding, such as oil immersed grinding wheel or internal cooling grinding wheel. When the cutting fluid is introduced into the center of the grinding wheel, the cutting fluid can directly enter the grinding area to play an effective cooling role and prevent workpiece surface burns.
2.The quenching stress after heat treatment is reduced to the minimum, because the quenching stress and network carbide structure produce phase transformation under the action of grinding force, which is very easy to cause cracks in the workpiece. For high-precision dies, in order to eliminate the residual stress of grinding, low-temperature aging treatment should be carried out after grinding to improve the toughness.
3.To eliminate grinding stress, the die can also be immersed in 260 ~ 315 ℃ salt bath for 1.5min, and then cooled in 30 ℃ oil. In this way, the hardness can be reduced by 1hrc and the residual stress can be reduced by 40% ~ 65%.
4.For precision grinding of precision die with dimensional tolerance less than 0.01mm, attention should be paid to the influence of ambient temperature and constant temperature grinding is required. According to the calculation, when the temperature difference of 300mm long steel is 3 ℃, the material is 10.8 μ About M, (10.8 = 1.2 × three × 3. 1.2 deformation per 100mm μ M / ℃), the influence of this factor should be fully considered in each finishing process.
5.Electrolytic grinding is adopted to improve die manufacturing accuracy and surface quality. During electrolytic grinding, the grinding wheel scrapes off the oxide film instead of grinding metal, so the grinding force is small and the grinding heat is small. There will be no grinding burr, crack, burn and other phenomena. Generally, the surface roughness can be better than Ra0 sixteen μ m; In addition, the wear of the grinding wheel is set to be small. For example, when grinding cemented carbide, the wear amount of the silicon carbide grinding wheel is about 400% ~ 600% of the weight of the ground cemented carbide. When electrolytic grinding is used, the wear amount of the grinding wheel is only 50% ~ 100% of the grinding amount of cemented carbide.
