As mechanical polishing is mainly done manually, polishing technology is still the main reason affecting polishing quality. Besides, it is also related to mold material, surface condition before polishing, heat treatment process and so on. High quality steel is a prerequisite for obtaining good polishing quality. If the surface hardness of steel is uneven or the characteristics are different, polishing will often be difficult. All kinds of inclusions and pores in steel are not conducive to polishing.
1、 the effect of different hardness on the polishing process is higher, the hardness increases, the grinding difficulty increases, but the roughness after polishing decreases. As the hardness increases, the polishing time needed to achieve lower roughness increases accordingly. At the same time, the possibility of excessive polishing will decrease as the hardness increases.
2 、the surface condition of the workpiece affects the polishing process. During the crushing process of cutting machine, the surface surface will be damaged by heat, internal stress or other factors, and the improper cutting parameters will affect the polishing effect. The surface of EDM is more difficult to grind than the surface of ordinary machine or heat treated surface, so the precision standard EDM should be used before the end of EDM, otherwise the hardened thin layer will be formed on the surface. If the accuracy of EDM is not properly selected, the depth of the heat affected layer can reach up to 0.4mm. The hardness of the hardened thin layer is higher than that of the substrate and must be removed. Therefore, it is best to add a rough grinding process, thoroughly remove the damaged surface layer, form an average rough metal surface, and provide a good foundation for polishing process.
        Chemical polishing needles need to be heated for applications where polishing is not high. As far as the current technology is concerned, chemical polishing will not be used if the above three kinds of polishing can be used, because the effect of chemical polishing is poor and the comprehensive cost is high.