Mold design cooling: good cooling design can effectively shorten the molding cycle and prevent mucous membrane. If necessary, beryllium copper with high thermal conductivity (such as AMPCO TM 940 or moldmax?) can be used to make these parts. The cooling channel of the mould should reduce the flow as much as possible, and the turbulent state of the cooling water flow should be considered in the design. The design and cooling of the main channel: copolyester is easy to film, and the following measures can be taken:

• 1. The cooling mode of turning up and down is adopted around the main channel.
• 2. Interference fit (0.005 mm) should be adopted during the assembly of sprue bushing to ensure the smooth transfer of heat from bushing to template.
• 3. Use high thermal conductivity material to make sprue bushing, such as beryllium copper.
• 4. The length of sprue bushing should not exceed 80mm, and the slope of one side should be at least 2 °.
• 5. Polish sprue bushing in parallel direction. Design of diversion channel: the design principles of most engineering plastics can be used for the system setting of diversion channel, including balance flow channel, fillet transition, cooling well, exhaust groove, full circle or semi-circular channel section, etc.