The planning of bottle cap mold needs to be based on the shape, accuracy, size, technical requirements and production batch of plastic parts. The following aspects should be considered in mold planning:
a. Number of cavities and placement method: as the bottle cap is produced in large quantities as a packaging container, it is appropriate to select the first mock examination with multiple cavities. Considering the mold locking force, injection volume of the existing injection molding machine, and the accuracy and economic factors of the bottle cap, it is determined as 1 mold with 10 cavities, and the placement method of the cavities is "straight line".
b. Pouring system planning: according to the layout of plastic parts, the mold is planned into three plates, and the point gate is selected. The gate is set in the center of the top of the plastic part. The point gate can significantly improve the shear rate of the melt, greatly reduce the melt viscosity, and is conducive to mold filling. PE is particularly useful for the melt with sensitive shear rate. Moreover, as a packaging container, the demand for appearance quality of plastic parts is high, and the residual trace of point gate is small, which can ensure the surface quality of plastic parts. When demoulding, the gate is actively broken, which is convenient to complete the automation of product production process, improve production power and increase economic benefits. The non-equilibrium pouring system is selected, the cavity is placed compactly, and the mold size is reduced. In order to make each cavity fill evenly together, the method is selected to manually correct the gate size of each cavity to achieve balance. Use cold material pockets to store cold materials.
c. Cooling system planning: the mold temperature conditioning system of bottle cap mold directly affects the quality and production power of products. In order to improve the cooling power of the cavity, the cooling circuit is selected. The inlet of one circuit is located near the outlet of the other circuit; According to the constraints of plastic part shape and mold layout, the diameter of fixed mold cooling water channel is φ 12mm, connected with the hose outside the mold to form circulating cooling. The diameter of the moving model core is small. The steel pipe cooling method is selected. The soft copper mandrel with good thermal conductivity is pressed into the middle of the core, and one end of the mandrel is extended into the cooling water hole for cooling.
