Why choose graphite mold for hot bending of mobile phone 3D glass?

Some mobile phones are now pursuing the so-called 3D glass. Compared with the metal casing of mobile phones, 3D glass processing is still difficult. In the 3D glass thermoforming process, the glass needs to be softened by high temperature and get shaped in the mold per requirement. Did you know that a graphite mold is required to make a curved piece of glass.

We know that whether it is injection molding, stamping or die-casting, the mold is made of metal steel. Then why does the 3D glass thermoforming process not use metal steel molds?

This is because metal materials deform greatly and become soft at high temperatures, while graphite has characters like high temperature resistance, good thermal conductivity, high hardness, corrosion resistance, and low cost. Unlike metal, the hardness of graphite increases with the increase of temperature. The higher the temperature, the harder the hardness, so that there is no problem of deformation, and the maximum degree of precision can be guaranteed.

3D glass hot bending has high requirements on graphite. High purity and high density of graphite are required. The high purity requirement is mainly to prevent graphite from being oxidized at high temperature to produce bubbles, which will affect the surface finish; The high density requirement is to prevent the collapse of the graphite mold, improve its mechanical strength as much as possible, and ensure that the life of the mold is greatly improved. . The surface finish of the mold cavity directly affects the surface effect of the 3D glass, and the surface of the mold cavity is not only related to fine polishing, but also closely related to the diameter of the graphite particles. Only the smallest particle diameter graphite can be processed to obtain a sufficiently smooth mold cavity.

At present, high-precision CNC graphite processing technology is used for the processing of hot bending graphite molds for 3D glass.