Mold making, finishing stage of the method commonly used by grinding, EDM and fitter processing, shape tolerances and dimensional accuracty, and many technical parameters, in particular the production, the operation more difficult, but still has some of experience to ensure methods.

A stamping die is made with a lot of parts, part a direct impact on the quality of the quanlity of the mold, and finishing parts to complete the final turn, the quality assurance, finishing grinding and EDM can be used, two characterized by various processing methods, mold different shapes that different processing effects.

1. Die finishing process control

Mold parts processing, is for different materials, different shapes, different technical requirements for adaptive processing, it has s certain plasticity, through the control of processing to achieve better processing results.

According to the apprearance of parts of different shapes can be roughly divided into three parts: shaft, sheet metal and shaped parts, the common process is roughly: rough - heat treatment – grinding – EDM – fitter (surface treatment) – group with processing.

2. Part heat treatment

Part of the heat treatment process to obtain the appropriate hardness for the same parts, the need to control the internal stress and ensure diamensional stability during machining parts to prevent the deformation of different materials each with a different approach. If the Cr12, 9CrSi, T10, and so on.

For the Cr12, 9CrSi, T10 as a material part, the rough treatment after quenching, after quenching the lifetime of the workpiece there is a big stress, easily lead to cracking of the workpiece finishing, parts to be hot tempered after quenching to eliminate the quenching stress. Encountered in the production of complex shape parts, tempering is not enough to eliminate quenching stress, finishing before the need for stress relief annealing, or multiple artificial aging treatment, the full release of stress. Chipping on to form the mold for the main failure is applicable.

3. Grinding of 3 parts

Grinding machine used, there are three main types: surface grinding machine, internal and external cylindrical grinding and tool grinding. Finishing grinding, strictly control the deformation, therefore, grinding the feed to be small, not large, the cooling fluid to adequate dimensional tolerance within 0.01mm part in the constant grinding as far as possible. To prevent thermal deformation of workpiece size errors of the finishing operations are required to fully consider the impact of this factor.

When choosing a proper grinding wheel grinding is very important, according to the sepcific conditions of the mold steel, selected for GD compared single-crystal corundum grinding, quenching hardness of the material, the preferred organic binder of the diamond grinding wheel, the organic binder self-sharpening wheel, grind the workpiece rough up Ra=0.2m. grinding, wheel dressing should pay attention to in a timely manner to maintain a sharp wheel, when the grinding wheel surface passivation will slip in the rub, squeeze, resulting in surface burn, the intensity decreased.

Most parts of the processing board using surface grinding machine, grinding to precision flat nose pliers, contour pads, dial indicator, block gauge, table seat and so ensure that the papallel, vertical, symmetrical size, small feed processing, multi-knife, after processing a good side, turning chucking alignment parallel, perpendicular, symmetric, this can improve the grinding effect, which can meet the technical requirements. Reposted elsewhere in the paper for free download shaft part with thr Rotary, its processing and the extensive use of internal and external grinding machine tool grinder. Processing the first multi-use process, positive and negative top, the center rack cards, if the center hole shape error exists, the same will be processed out of the workpiece have this problem, affecting the quality of parts, so fine in the processing before training center hole. For bore grinding, grinding rod out of the Imam and the speed is high, less rigid rod wheel, grinding wheel and workpiece to reduce contact area, the wheel can be trimmed to a cone, only a few front end about 4-6mm contact wirh the workpiece can be fully reduced grinding resistance is smaller when the grinding feed, no feed knife several times,until the wheel little time for cremation can then feed, processing, thin-walled sleeve part, the best use of technology elastic sleeve workpiece to prevent workpiece deformation, the circumference of the workpiece or easy to produce “ the other triangle”shape.

4. Electrical Process Control

Modern mold factory, can not be lack of processing power, power processing for all types of sepcial-shaped, high hardness amd parts for processing it is divided into two kinds of wire cutting and EDM.

High precision wire cutting, processing begins, the first prr-processing of the general shape and then heat treatment, and conduct heat to the stress, so that heat treatment before the first release of stress in the finish, to ensure thermal stability. After treatment, the surface grinder, and grind a reference plane to reference plane position, the EDM processing shaped cavity, so that the workpiece has been completely deformed in the heat treatment, no longer in finishing deformation.

Processing punch, the wire cut into the location and path selection to be carefully considered chucking methods and fixation shoule be reasonable, because the line cutting, the workpiece in the pricess can not move, instaleed cards can be used in a traditional plate loeaded card, you can also pick a metal strong adhesive, magnets and other equipment card way, high precision wire cutting, often cutting the number of times for the two, can guarantee part quality. When processing with taper die, the spirit of the principles of fast and efficient, first pass rough straight edge, the second taper processing times, followed finishing straight edge, so that only the finishing straight edge blade section, which saves time and cost savings.

5. A group 5 with surface treatment

Parts of the surface marks left behind in the processing, is worn where stress concentration is the source of crack propagation, after the end of the process, the need for parts for surface hardening, grinding through the fitter, disposed processing risks. Some of the workpiece edges, sharp angles, the back orifice blunt, R technology. EDM surface will produce about 6-10m metamorphic hardened layer, the color was gray, brittle and hardened layer with residual stress, prior to fully eliminate the use of hardened layer, the method for surface polishing, grinding hardened layer removed.

In grinding, processing power, there will be some magnetic parts, with a week magnetic force, is very easy to suck some small iron foam, in the assembly prior to demagnetization of the workpiece, the assembly process, the general assembly of the first put on planes. After the punch and die with, and then again throughout the gap, especially in the group with punch and die clearance adjustment, the implementation of the mold assembly after completion of testing of the problems found, from finishing to roughing, each check until you find the crux of the problem, solve the problem.

6. Conclusion

Practice has proved that food control of the finishing process can be effectively reduced tolerance parts, scrap, improve the success rate and a mold life.