Mold design and manufacturing are closely related to plastic processing. The success or failure of plastic processing largely depends on the effectiveness of mold design and the quality of mold manufacturing, and plastic mold design is based on the correct design of the plastic product.
Structural elements to consider in plastic mold design include:
Parting surface: The contact surface where the die and punch meet when the mold is closed. Its position and form are influenced by factors such as the shape and appearance of the product, wall thickness, molding method, post-processing technology, mold type and structure, demolding method, and molding machine structure.
Structural components: These include sliders, angled ejectors, and ejector blocks in complex molds. The design of structural components is crucial, affecting mold life, processing cycle, cost, and product quality. Therefore, designing the core structure of complex molds requires a high level of comprehensive ability from the designer, aiming for a simpler, more durable, and more economical design solution.
Mold precision: This includes anti-jamming devices, precision positioning, guide pillars, and locating pins. The positioning system is crucial to the appearance quality of the finished product, as well as the quality and lifespan of the mold. Different positioning methods are selected based on the mold structure. Positioning accuracy control primarily relies on machining, while internal mold positioning requires careful consideration by the designer to design a more rational and easily adjustable positioning method.
The gating system, i.e., the material flow channel from the injection molding machine nozzle to the cavity, includes the main runner, branch runners, gate, and cold slug well. In particular, the selection of the gate location should facilitate the molten plastic to fill the cavity in a good flow state, and the solid runners and cold slugs adhering to the product should be easily ejected and removed from the mold upon mold opening (except for hot runner molds).
Plastic shrinkage rate and various factors affecting the dimensional accuracy of the product, such as mold manufacturing and assembly errors, mold wear, etc. Furthermore, when designing compression molds and injection molds, the matching of the molding machine's process and structural parameters should also be considered. Computer-aided design technology is widely used in plastic mold design.
