Structure factors and related knowledge to be considered in plastic mold design

   Plastic mold design is based on the correct design of plastic products. Mold design and manufacturing are closely related to plastic processing. The success or failure of plastic processing largely depends on the mold design effect and mold manufacturing quality
1. Parting surface is the contact surface between the punch and the die when the die is closed. The selection of its position and form is affected by the shape and appearance of the product, wall thickness, forming method, post-processing technology, mold type and structure, demoulding method and forming machine structure.
2. Structural parts, i.e. slide block, inclined block and straight block of complex die. The design of structural parts is very critical, which is related to the life, processing cycle, cost and product quality of the mold. Therefore, the design of complex mold core structure requires higher comprehensive ability of the designer, and pursues a simpler, more durable and more economical design scheme as far as possible.
Die structure design
The size of plastic parts is small, the accuracy of products is low, the requirements of good performance, no cracks, bending resistance, and mass production. The first mock exam is designed to be a eight cavity structure, and the following problems are solved.
1、 Balance of gating system when designing multi cavity mold, all cavities should be fed at the same time as much as possible. As the number of cavities increases, the length of shunt channel will increase. Before the molten material reaches the cavity, the injection pressure and heat of molten material will be greatly lost. If the design of shunt channel is slightly unreasonable, the plastic part may have defects, such as insufficient injection in one cavity or several cavities, If the injection pressure is increased, the flash is easy to occur. In this paper, the design of the runner is non-equilibrium layout, by setting the size of the gate and shunt, the injection process is adjusted to the value, to ensure that the shrinkage of each cavity is consistent, the plastic parts with the highest precision requirements, to ensure its interchangeability, the position of the gate is set at the thick end of the plastic parts, marked as the Y end, which is conducive to flow and feeding, but also can avoid the generation of weld marks, molecules have directivity Meet the requirements of bending without fracture.
2、 Design of cooling system the design principle of the cooling device is to design the cooling device on the basis of not increasing the structure of the mold itself. On the premise of meeting the transfer area required for cooling and the structure of the mold, the number of cooling circuits should be designed as many as possible, and the diameter of the cooling channel should be as large as possible. The cooling water holes should be machined on the upper and lower cavity plates and the dynamic and fixed templates for installation The cooling water hole of the upper cavity plate is connected with the water hole of the fixed template, and then sealed with a sealing ring. The cooling water hole of the lower cavity plate is connected with the water hole of the moving template, and also sealed with a sealing ring. The water holes are arranged on the upper and lower cavity plates and the moving template.