How To Reduce The Defects In Plastic Mould Processing?

Update:08-07-2021
Summary:

  1.cooling, washing and lubrication, keep cooling and […]

  1.cooling, washing and lubrication, keep cooling and lubrication clean, control the grinding heat within the allowable range, and prevent thermal deformation of the workpiece. Improve the cooling conditions during grinding, such as the use of sinking wheels or internal cooling wheels. The cutting fluid is introduced into the center of the grinding wheel. The cutting fluid can directly enter the grinding area to effectively cool down and prevent burns on the surface of the workpiece.

 

  2. Minimize the quenching stress after heat treatment, because the meshed carbonized structure under the quenching stress and the grinding force causes the structure to undergo phase transformation and easily cause the workpiece to crack. In order to eliminate the residual stress of high-precision mold grinding, low temperature aging treatment should be carried out after grinding to improve toughness.

 

  3. In order to eliminate the grinding stress, the mold can be immersed in a salt bath at 260~315℃ for 1.5min, and then cooled in 30℃ oil, which can reduce the hardness by 1HRC and the residual stress by 40% ~ 65%.

 

  4. For precision grinding of precision molds with dimensional tolerances within 0.01mm, attention should be paid to the influence of ambient temperature and constant temperature grinding is required. According to calculations, when the temperature difference is 3℃, the material changes about 10.8m (10.8=1.2×3×3, and the deformation per 100mm is 1.2m/℃), and the influence of this factor should be fully considered in each process. The finishing process.

 

  5. Electrolytic grinding is used to improve mold manufacturing accuracy and surface quality. In the electrolytic grinding process, the grinding wheel squeezes the oxide film instead of grinding the metal. Therefore, the grinding force is small, the grinding heat is small, and there will be no burrs, cracks, burns, etc. Generally, the surface roughness can be better than Ra0.16 m. In addition, the grinding wheel wear is very small. For example, when grinding cemented carbide, the amount of wear of a silicon carbide grinding wheel is about 400% to 600% of the weight of the cemented carbide. In electrolytic grinding, the wear amount of the grinding wheel is only 50% to 100% of the grinding amount of cemented carbide.

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