The design of pet preform mould is based on the correct design of pet preform products. The design and manufacture of mould are closely related to pet preform processing. The success or failure of pet preform processing largely depends on the mold design effect and mold manufacturing quality. The structural elements that need to be considered in the design of pet preform molds are:
- parting surface, i.e. the contact surface where the female die and the male die cooperate with each other when the die is closed. The selection of its position and form is affected by the shape and appearance of the product, wall thickness, molding method, post-processing technology, mold type and structure, demolding method and molding machine structure, etc.
- Structural parts, i.e. slide block, inclined top, straight top block of complex molds, etc. The design of structural parts is very critical and related to the life, processing cycle, cost, product quality, etc. Therefore, the design of complex die 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 accuracy, i.e. avoiding jamming, fine positioning, guide pillar, positioning pin, etc. Positioning system is related to product appearance quality, mold quality and service life. Different positioning methods are selected according to different mold structures. Positioning accuracy control mainly depends on processing. Internal mold positioning is mainly considered by designers to design a more reasonable and easy-to-adjust positioning method.
- Pouring system, that is, the feeding channel from the injection molding machine nozzle to the mold cavity, including the main flow channel, the shunt channel, the gate and the cold material cavity. In particular, the location of the gate should be selected so that the molten pet preform can fill the cavity in a good flow state, and the solid runner and gate cold material attached to the product can be easily ejected from the mold and removed when the mold is opened ( except for the hot runner mold ).
- pet preform shrinkage and various factors affecting the dimensional accuracy of products, such as mold manufacturing and assembly errors, mold wear, etc. In addition, when designing the compression mold and injection mold, the matching of process and structural parameters of the molding machine should also be considered.