In order to improve the application function of the mold, many manufacturers will process the mold properly. Mold processing refers to the processing of the forming and blank making tools, in addition to the cutting mold and die-cutting mold. But in many cases, the mold processing will also reflect the processing defects, resulting in the decline of the mold function, so how to build the mold processing defects? The following seven methods can be used to build mold processing defects, next by Shandong mold editor to share with you.
1. It is better to select and trim the grinding wheel reasonably and select the white corundum grinding wheel. Its function is hard and brittle, and it is easy to produce new cutting edge. Therefore, the cutting force is small, and the grinding heat is small. The use of medium grain size, such as 46-60 mesh, is better. The use of medium soft and soft (ZR1, Zr2 and R1, R2) in the hardness of the grinding wheel, that is, the grinding wheel with coarse grain size and low hardness, with good self excitation, can reduce the cutting heat.
It's very important to choose the right grinding wheel for fine grinding. In view of the high vanadium and high molybdenum situation of die steel, it's more suitable to choose GD single crystal corundum grinding wheel. When processing the hard alloy and the material with high quenching hardness, the diamond grinding wheel with organic binder is preferred. The grinding wheel with organic binder has good self grindability and the workpiece roughness can reach Ra0.2 μ M. in recent years, with the application of new materials, CBN The grinding wheel (CBN) shows a very good machining effect. It is better than other kinds of grinding wheels in finishing on CNC forming grinding machine, coordinate grinding machine and CNC Internal and external cylindrical grinding machine.
In the grinding process, we should pay attention to timely dressing the grinding wheel, adhere to the sharpness of the grinding wheel, when the grinding wheel is passivated, it will rub and squeeze on the surface of the workpiece, resulting in burn on the surface of the workpiece and strength reduction.
2. Reasonably use the cooling smooth liquid, give play to the three effects of cooling, washing and smoothing, adhere to the cooling smooth cleaning, and then control the grinding heat within the allowable range to prevent the workpiece from thermal deformation. Improve the cooling conditions during grinding, such as selecting the immersion 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 effect and prevent the surface of the workpiece from burning.
3. The quenching stress after heat treatment is reduced to a low level. Because the quenching stress and network carbonization are arranged under the effect of grinding force, the phase transformation is arranged to make the workpiece crack easily. In order to eliminate the residual stress in grinding, the high-precision die should be aged at low temperature to improve its toughness.
4. The mould can also be immersed in 260-315 ℃ salt bath for 1.5 min to eliminate grinding stress, and then cooled in 30 ℃ oil, so the hardness can be reduced by 1 HRC, and the residual stress can be reduced by 40% - 65%.
5. For the precision grinding of precision die with dimension less than 0.01 mm, it is necessary to pay attention to the influence of environment temperature and require constant temperature grinding. It can be seen from the calculation that when the temperature difference of 300 m m long steel parts is 3 ℃, the material changes about 10.8 μ m, (10.8 = 1.2 × 3 × 3, 1.2 μ M / ℃ for every 100 mm deformation). The influence of this factor should be fully considered in each finishing process.
6. Electrolytic grinding is selected to improve the accuracy of mold making and appearance quality. In electrolytic grinding, the grinding wheel scrapes off the oxide film instead of grinding the metal, so the grinding force is small, the grinding heat is small, and there will be no grinding burr, crack, burn and other phenomena. Generally, the surface roughness can be better than ra0.16 μ m; in addition, the wear of the grinding wheel is small, such as grinding hard alloy, the wear of silicon carbide wheel is about 400% - 600% of the grinding hard alloy component, When electrolytic grinding is used, the wear amount of grinding wheel is only 50% - 100% of that of cemented carbide.
7. Reasonable selection of grinding amount, selection of radial feed smaller precision grinding method or even precision grinding. If the radial feed rate and the grinding wheel speed are properly reduced and the axial feed rate is increased, the contact area between the grinding wheel and the workpiece is reduced, the heat dissipation condition is improved, and then the surface temperature is effectively controlled.
The above is the whole content of reducing mold processing defects. Shandong mold is dedicated. If you have other questions, please consult Shandong mold official website http://www.ok9868.com !