Design Principles For Plastic Molds

- Sep 13, 2018-

The plastic mold imparts the desired shape, quality, cooling and ejection of the plastic to the plasticized plastic. The mold determines the performance, shape, size and precision of the final part. Therefore, the design of advanced and reasonable injection mold structure is the key to obtaining quality requirements, stable product quality and achieving the best economic benefits. To do a good job in plastic mold design, we must grasp the following principles:


1. The selection of the parting surface is reasonable.


The parting surface allows the product and the gating system to be removed from the mold. It is the structure that must be set in the mold. It determines the mold structure and also determines the processing technology of the mold. And affect the flow of the melt and demolding of the plastic parts. The overall selection principle of the parting surface is to ensure the quality of the plastic part, simplify the mold structure, and facilitate the demoulding. The choice of the location of the parting surface follows the "three no-principles": it is not in the obvious position and affects the shape, and it is not allowed to form a depression or a position that is not easy to process.


2. The draft angle is properly selected.


Draft angle is a necessary condition for the product to be smoothly removed from the mold. The size of the draft is different depending on the shape of the molded article, the type of plastic, the structure of the mold, the surface precision, and the processing direction. There is no precise calculation formula for the draft angle. In most cases, depending on the empirical value, a large draft angle is taken without hindering production.