The analysis of the mold precision manufacturing

A set of mold is composed of many spare,and the quality of the mold accessories  made a direct impact on the quality of the whole mold , and the final quality of the    parts is guaranteed by the high precision machining.

As for the most of the domestic manufacturing enterprises, the precision machining   usually includes  grinding, EDM and fitter treatment. Meanwhile ,we should control the deformation of parts, internal stress, shape tolerances , dimensional accuracy, and many   other technical parameters, in the real production ,the operation will be more difficulty.

For the mold parts machining, generally known as adaptive processing for different  materials, different shapes and different technical requirements .

According to the different shapes of the parts ,we can divide the parts into  three   categories:they are shafts, sheet metal and shaped parts, their common process includes   heat treatment  - grinding - Electric Discharge - surface treatment-assembly

1:heat treatment

By heat treatment process, the die components can reach the required hardness while controlling the internal stress, ensuring dimensional stability when machining the parts,   Normally ,different materials have different way to do the heat treatment. With the recent development of the mold industry, there’re more types of materials to be used, Beside the material Cr12, 40Cr, Cr12MoV, carbide, but for some work intensity, force demanding convex and concave mold, the choice ,we also use V10, ASP23 for better  thermal stability and good performance .

2 Grinding

There’re three types of grinding,: surface grinder, cylindrical grinding and tooling grinding .We should  strictly control the finishing deformation and cracks when grinding, even for the micro crack ,it will influence the overall mold performance.

3:  Electrical machining

In the modern mold factory,  electrical machining is necessary , especially for the molds of the precision sheet metal stamping parts.All kinds of special-shaped with high      hardness parts can be machined by electrical machining ,it is divided into two kinds of wire EDM and E.D.M.

4: Surface treatment and assembly

The marks and Scar is the place where the stress is concentrated ,also it is the     source of crack propagation, so after processing, we should do the surface hardening to the parts and  dispose of processing problems by grinding ,and do the radius treatment to the   sharp holes and sides . In generally ,there will be about 6-10μm deterioration of the hardened layer when E.D.M, the color is gray,  hardened layer is brittle .so before using ,we need to eliminate the hardened layer by  surface polishing .

During the  grinding, electric machining, some machining will be magnetized ,it is   very easy to suck some small things, so before  assembly ,we should prior to the workpiece for demagnetization and clean the surface with ethyl acetate.In the assembly process,  we should prepare all mold accessories for assembly ,and make lists of assembly,the assembly usually start from the mounted guide pins and bushings, and then loading mode frame and punch and die, and adjust  the gap, especially for groups with punch and die gap then  mold testing, write the detailed report. If any problems,we’re able to check by    reverse thinking method, it is from the process after step forward, from finishing to roughing, check each until you’re able to find the  problem.