What are the design and manufacturing methods for stamping dies?

In the production of automotive stampings, hot stamping technology is effective in considering lightweighting and crash safety, as well as rebound and die wear of stamped parts at high strength, compared to cold stamping, and has attracted attention. Hot stamping should be realised by means of its forming dies, and the efficiency of stamping and forming is directly related to whether the die design is reasonable or not. What are the main influencing factors for the structural design of a hot forming die?

In the structural design of hot forming moulds, the main influencing factors are: insert cooling system arrangement, mould strength, mould sealing, etc. The most important of these is the insert cooling system arrangement to ensure a certain cooling rate of the hot formed parts after forming. Accordingly, the design and manufacturing methods of hot stamping moulds are divided into four main types: drilling type, layered type, leaching type, melting type and casting type. What are the advantages and disadvantages of each of these methods? Please read on!

1. Drilling type

The drilling type maximises the arrangement of the tubing under the convex and concave mould faces, enabling the arrangement of the inlay cooling system. This type is just as easy to process, easy to change moulds and has good versatility, but there is no way to process using moulds and the cooling of the moulds is not uniform.

2. Layered type

Layered processing is to use the cooling tube as the interface between the mould surface and other parts of the mould, with the advantages of good follow-up, large heat transfer area, simple sealing, etc. The disadvantage is that high-precision processing equipment is required, the cooling tube is complex and the heat transfer performance is poor.

3. Shower type

By setting a series of small holes in the mould surface, set nozzles in the holes, the high pressure coolant sprayed into the hot steel plate to achieve quenching and cooling, the advantage is good cooling effect, the material phase change is sufficient, excellent mechanical properties of the parts, the disadvantage is that processing difficulties, residual water droplets on the mould serious damage to the surface of the mould, reduce the life of the mould.

4. Melt casting type

Melt-casting type by fixing the cooling tube as a whole embedded in the sand, using the casting method to obtain the mould blank, after processing to get a complete mould, flexible cooling tube arrangement, good tracking, simple and reliable pipe sealing, easy processing; disadvantage is the poor strength of the mould, melting casting process is complex, realize the metallurgical combination of pipe and substrate, high positioning accuracy, difficult to realize the local pressure mould repair.

Among the four types of hot stamping mould design and manufacture, drilling and layering are the most widely used.