Knowledge

According to the shape of the lunch box, design a suitable mold structure, such as adopting the design of the first mock examination with four cavities, and using the side gate to

Carving and shaping gypsum in a semi wet state, and then drying it to form a mold.

The selection of mold materials should be reasonable, and engineering plastics or alloy steels that are wear-resistant, heat-resistant, and corrosion-resistant should be selected.

If there are many parts of the mold that are worn out, the method of inlaying can be used to make the entire surface of the mold smooth.