At home most of the mould manufacturing enterprise, the finishing stage grinding, electric processing methods are generally and fitter. At this stage to control the deformation and internal stress, shape tolerance and dimensional accuracy many technical parameters, such as in concrete production practice, the operation more difficult, but there are still many effective methods of experience is worth reference, such as the following several kinds.
1/Mould finishing process control
Mold parts processing, is a general guideline for different material, different shape, different technical requirements for adaptive processing, it has certain plasticity, can through the control of the processing, to achieve a good processing effect.
According to the shape of the appearance of the parts is different, can put the parts roughly divide people into three categories: shaft, plate and special-shaped parts, their common process for roughly: rough machining, heat treatment (quenching and tempering) - fine grinding, electric processing, fitter (surface treatment) - equipping processing.
2/heat-treatment
Parts of heat treatment process, the hardness of the parts get requirements at the same time, still need to control the internal stress, guarantee the stability of the parts processing when the size of different materials have different ways of processing respectively. With the development of mold industry in recent years, the use of the material increased, in addition to the Cr12, 40 cr, Cr12MoV, hard alloy, for some working strength, stress strict convex and concave die, can choose new materials of powder alloy steel, such as V10, ASP23, this material has high thermal stability and good organization state.
For Cr12MoV as material parts, quenching after rough machining, and left a lot of stress after quenching, craze, easy to cause the finishing or work parts should be hot tempering after quenching, quenching stress. Quenching temperature control at 900 ℃ to 1020 ℃, then cool to 200 ℃ to 220 ℃ from air cooling, then quickly returns to 220 ℃ tempering, this method is called a hardening process, can obtain high strength and wear resistance, to wear as the main failure forms of mould effect is better. Encountered in the production of some of the more complicated shape in the corner of workpiece, tempering is not sufficient to eliminate the quenching stress, still need to go before finishing annealing or aging treatment for many times, fully release the stress.
For V10, APS23 powder alloy steel parts, because it can withstand the high temperature tempering, quenching can be adopted when the secondary hardening process, the 1050 ℃ to 1080 ℃ quenching, with 490 ℃ to 520 ℃ high temperature tempering and for many times, can obtain higher impact toughness and stability, to collapse as the main failure forms of blade mould. Powder alloy steel cost is higher, but its performance is good, is forming a kind of widely used.