What Are the Things to Consider when Designing a Plastic Mold?

The characteristics of plastic molds of plastic mold factories are determined by the characteristics of raw materials. There are two main points: one is the mold filling flow characteristics of the plastic melt during injection, and the other is the shrinkage position of the plastic in the mold cavity when it cools and solidifies. These two points determine the particularity of injection mold and the difficulty of injection mold design.

Ⅰ. The characteristics of plastic mold design

Since the plastic melt is a viscoelastic body, the viscosity of the melt changes with the shear stress and shear rate. During the flow process, the macromolecules are oriented along the flow direction. After the cavity is filled, the melt is partially compressed, and the process of cooling and solidification and the shrinkage of plastic are very complicated. The plastic shrinkage rate of each part in the mold cavity is different in all directions. The plastic shrinkage rate of different types and grades is very different. When the resin or plastic of the same grade is processed, due to different formulations, the mold filling fluidity and shrinkage rate are also different.

Based on the above characteristics, the plastic mold maker supplier should fully understand the characteristics of the processed plastic raw materials and effectively give full play to the characteristics of plastics in the design process, so that the designed injection molds can be used reasonably.

Ⅱ. Precautions for the plastic mold design are as follows:

1. In-depth analysis of the structure and technical requirements of plastic moulds for sale parts. The structure of the plastic part determines the complexity of the injection mold structure, and the technical requirements (dimensional accuracy, surface roughness, etc.) of the plastic part determine the difficulty of the injection mold manufacturing and molding technologies. Therefore, for plastic injection molding that does not meet the special requirements, unreasonable structure and shape, the plastic mold factory should put forward improved design of injection parts, otherwise it will increase the difficulty of design and manufacturing of injection mold and injection molding technologies;

2. Be familiar with the technical specifications of the injection molding machine. The technical specifications of the injection molding machine restrict the size of the injection mold and the range of injection products that can be molded;

3. Plastic mold factories should understand the processing performance and technological performance of plastics, including the flow position of the plastic melt, the large flow distance ratio that the melt can achieve: the injection mold manufacturer should analyze the flow resistance of the runner and the cavity, the discharge of the original air in the cavity, the plastic in the injection mold, possible crystallization, orientation and its resulting internal stress of plastic in injection mold, plastic cooling shrinkage and compensation problems, the requirements of plastic for injection mold temperature, etc.