Plastic mold design must consider the following critical structures to ensure successful manufacturing:
Parting Surface: This refers to the mating contact surface between the mold cavity and core when the mold closes. The selection of its location and form is influenced by factors such as the product's shape, appearance, wall thickness, molding method, post-processing techniques, mold type and structure, ejection method, and molding machine structure1.
Structural Components: These include sliders, angled lifters, and straight lifters in complex molds. The design of these components is crucial as it directly impacts mold lifespan, production cycle time, cost, and product quality. Designing the core structures of complex molds demands high comprehensive capabilities from designers, who strive for solutions that are simpler, more durable, and more economical12.
Mold Precision: This encompasses ejection avoidance mechanisms, precision locating pins, guide pins, and snap rings. The positioning system significantly affects product appearance quality, mold quality, and service life. Different positioning methods are chosen based on the mold design, with precision control relying heavily on machining. Core positioning requires designers to thoroughly consider and design effective, easily adjustable positioning methods13.
Gating System: This is the feed channel from the plastic machine nozzle to the mold cavity, including the sprue, runners, gates, and cold slug wells. Crucially, the gate location should facilitate the cavity being filled smoothly by the molten plastic under favorable flow conditions. The solidified runners and gates attached to the product should be easy to eject and remove from the mold during demolding14.
Plastic Shrinkage and Precision Factors: Design must account for plastic shrinkage rates and other factors affecting dimensional accuracy, such as mold manufacturing and assembly tolerances, and mold wear. Additionally, when designing compression or injection molds, the matching with the molding machine's process and structural parameters must be considered. Computer-aided design (CAD) technology is now widely applied in plastic mold design. Furthermore, the incorporation of mold standard parts is essential to optimize overall mold performance and ensure smooth progress during the injection molding process14.
These structural considerations are fundamental to achieving highquality plastic mold design and manufacturing outcomes