Which two points should be paid special attention to in the design of the mould for the cushion belt mould?

Adjust according to the fluidity and vulcanization behavior of rubber, and the influence of the fluidity and vulcanization behavior of rubber on the overall design of the project, especially the relationship with the design project with greater influence. The basic structure and design project of pressure vulcanization mold and injection molding vulcanization mold. Rubber mold can be divided into two categories: compression molding and injection molding, but their basic structure is not very different.

As a design factor closely related to fluidity and vulcanization behavior, there are design of vent, flow channel, injection port, number and configuration of die cavity, etc.

Compared with the mold design, Japan rubber mold research branch emphasizes the following two points in the design of rubber mold:

1) as there are more air and volatile in rubber, and the gas decomposed by vulcanizer will be produced during vulcanization, so gas removal is a key problem. Since the vent hole is the place where the pressure is concentrated, the design of the vent hole structure on the pressure die PL surface is extremely important, because the bad phenomena in vulcanization are mostly concentrated on the vent hole.

2) in order to carry out the vulcanization reaction, the scorch stability of the rubber in the flow should be fully considered, at the same time, the rise of the pressure in the mold cavity during the vulcanization process, as well as the dispersion and orientation of the admixture should be considered. In the mold design, especially for the fluidity (  viscosity, pressure loss, stress relaxation)   and the factors with high correlation with vulcanization behavior were discussed. However, due to the lack of quantitative discussion, only the direction of mold design can be explained. The length of the standard sealing surface of the rubber mold varies with the volume of the mold cavity, generally 0.3-4.5mm, and the basic structure is a single vent. The clearance of PL surface is about 0.02-0.03mm   and the interface between PL surface and die cavity can only be R-shaped, which is to avoid stress concentration in this part.