Many industrial products and civilian products have internal and external thread design, and solving the plastic partde-molding problem is the key to such mold design. Generally speaking, there are two types of methods for dealing with plastic part thread: type one, the method of forced de-molding; type two, plastic part with deep thread, high resin strength and high thread precision, which must be rotated and pulled out. In the rotary unthreading structure, it is divided into manual decoupling and unthreading. The production efficiency is low, but the mold structure is simple, and it is suitable for small batch production; the automatic thread (un-screwing) removal efficiency is high, quality is stable, and it is suitable for mass production. In the automatic rotary unthreading mold structure, problems such as stability and practicability must be solved. Enuo mold can design and manufacture automatic de-molding mold structure for chain, rack and pinion, tofu, electric motor and other transmissions. After long-term use, the mold structure is stable and reliable, the production efficiency is high, and the product meets practical requirements.