Whether the design of Table Mould is reasonable or not will directly affect the quality of plastic products. Because the cavity size of the table mould is obtained from the required size of plastic products plus the shrinkage rate of the materials used, and the shrinkage rate is often a value within a range recommended by plastic manufacturers or engineering plastics manuals, which is not only related to the gate form, gate position and distribution of the table mould, but also related to the crystalline orientation (anisotropy) of engineering plastics, the shape and size of plastic products and the distance and position from the gate. The main factors affecting the shrinkage of plastics include thermal shrinkage, phase change shrinkage, orientation shrinkage, compression shrinkage and elastic recovery, which are related to the moulding conditions or operating conditions of precision injection moulding products.
Therefore, the designer of table mould must have rich experience in design and injection moulding, and must consider the relationship between these factors and injection conditions and their apparent factors, such as injection pressure, cavity pressure and filling speed, injection melt temperature and mould temperature, mould structure and gate form and distribution, as well as gate cross-sectional area, product wall thickness, reinforcing filler content in plastic materials, crystallinity and orientation of plastic materials, etc. The influence of the above factors is also different due to different plastic materials or other moulding conditions such as temperature, humidity, continuous crystallization, internal stress after moulding, and changes of injection moulding machine.