How To Reduce Shortcomings In Plastic Mold Processing

1. Reasonable application of cooling lubricating fluid to play the role of cooling, washing and lubrication, to maintain cooling and lubrication clean, so as to control the grinding heat within the allowable limit to prevent thermal deformation of the workpiece. Improve the cooling conditions during grinding, such as the use of oil-immersed grinding wheels or internally cooled grinding wheels. Introduce the cutting fluid into the middle of the grinding wheel, the cutting fluid can simply enter the grinding area, exert a useful cooling effect, and prevent burns on the surface of the workpiece.

2. The quenching stress after heat treatment is reduced to a very low limit. Due to the quenching stress and the net-like carbonized structure under the influence of the grinding force, the structure undergoes phase transformation and it is easy to crack the workpiece. To deal with high-precision molds, in order to eliminate the residual stress of grinding, low temperature aging treatment should be carried out after grinding to improve toughness.

3. To eliminate the grinding stress, the mold can also be immersed in a salt bath at 260～315℃ for 1.5min, and then cooled in 30℃ oil, so that the hardness can be reduced by 1HRC and the residual stress can be reduced by 40%～65%.

4. For the tight grinding of tight molds whose size is within 0.01 sister, attention should be paid to the influence of temperature and constant temperature grinding is required. It can be seen from calculations that when the temperature difference of 300 sister-long steel parts is 3℃, the material has a change of 10.8μm (10.8=1.2×3×3, the deformation amount per 100 sisters is 1.2μm/℃), and each finishing process requires Consider the influence of this ingredient.

5. Electrolytic grinding is adopted to improve the precision of mold making and surface quality. During electrolytic grinding, the grinding wheel scrapes off the oxide film: instead of grinding the metal, the grinding force is small, the grinding heat is also small, and there will be no signs of grinding burrs, cracks, burns, etc., and the ordinary surface roughness can be better than Ra0 .16μm; In addition, the wear of the grinding wheel should be small, such as the grinding of cemented carbide. The wear of the silicon carbide grinding wheel is about 400% to 600% of the amount of the cemented carbide that is ground. When electrolytic grinding is used, the wear of the grinding wheel The amount is only 50% to 100% of the hard alloy grinding amount.