Mold design considerations
The structural elements to be considered in plastic mold design are:
① Parting surface, that is, the contact surface between the concave mold and the convex mold when the mold is closed. The selection of its position and form is affected by factors such as product shape and appearance, wall thickness, molding method, post-processing technology, mold type and structure, demoulding method and molding machine structure.
② Structural parts, that is, sliders, inclined tops, straight top blocks, etc. of complex molds. The design of structural parts is very critical and is related to the life of the mold, processing cycle, cost, product quality, etc. Therefore, the design of the core structure of complex molds requires high comprehensive capabilities of designers, and the pursuit of simpler, more durable and more economical design solutions is as much as possible.
③ Mold accuracy, that is, card avoidance, precise positioning, guide pillars, positioning pins, etc. The positioning system is related to the appearance quality of the product, mold quality and life. Different positioning methods are selected according to different mold structures. Positioning accuracy control mainly depends on processing. The positioning of the inner mold is mainly considered by the designer to design a more reasonable and easy-to-adjust positioning method.
②Gating system, i.e., the feed channel from the injection molding machine nozzle to the cavity, including the main channel, branch channel, gate and cold material hole. In particular, the selection of the gate position should be conducive to the molten plastic filling the cavity in a good flow state, and the solid runner and gate cold material attached to the product can be easily ejected from the mold and removed when the mold is opened (except for hot runner molds).
③Plastic shrinkage rate and various factors affecting the dimensional accuracy of the product, such as mold manufacturing and assembly errors, mold wear, etc. In addition, when designing compression molds and injection molds, the matching of the process and structural parameters of the molding machine should also be considered. Computer-aided design technology has been widely used in plastic mold design.