Design elements for plastic moulds

Plastic moulds are tools used in the plastics processing industry and plastic forming machines to give plastic products a complete configuration and precise dimensions. Because of the variety of plastic and processing methods, plastic molding machine and plastic products and the structure of the simple and complicated, so, plastic moulds are also a variety of types and structures.

Mould design and manufacture are closely related to plastic processing. The success or failure of plastic processing depends to a large extent on the effectiveness of mould design and mould manufacturing quality, while plastic mould design is based on the correct design of plastic products.

The structural elements to be considered in the design of plastic moulds are.

1. parting surface, i.e. the contact surface where the concave and convex moulds fit each other when the mould is closed. Its location and form are influenced by the shape and appearance of the product, wall thickness, moulding method, post-processing process, mould type and structure, demoulding method and moulding machine structure.

2. Structural parts, i.e. sliders, sloping tops, straight tops, etc. of complex moulds. The design of structural parts is very critical, which is related to the life of the mould, processing cycle, cost, product quality, etc. Therefore, the design of the core structure of complex moulds requires a high comprehensive ability of the designer to pursue a simpler, more durable and more economical design solution as far as possible.

3. Mould accuracy, i.e. card avoidance, fine positioning, guide pillars, positioning pins, etc. Positioning system is related to product appearance quality, mould quality and life, according to different mould structure, choose different positioning methods, positioning accuracy control mainly rely on processing, internal mould positioning is mainly the designer to fully consider, design a more reasonable and easy to adjust the positioning method.

4, the pouring system, i.e. from the injection moulding machine nozzle to the cavity between the feed channel, including the main flow channel, diversion channel, gate and cold material cavity. In particular, the location of the gate should be selected to facilitate the molten plastic in a good flow state full of cavity, attached to the product of the solid runner and gate cold material in the mould when the opening is easy to eject from the mould and be removed (except for hot runner mould).

5. plastic shrinkage and factors that affect the dimensional accuracy of the product, such as mould manufacturing and assembly errors, mould wear, etc. In addition, when designing compression moulds and injection moulds, the process and structural parameters of the moulding machine should also be considered to match. Computer-aided design techniques have been widely used in the design of plastic moulds.