Руководства по проектированию деталей

A plastic injection mold is a tool whose cavity and core surfaces form the part geometry. In thermoplastic molding, molten plastic enters the closed tool, cools sufficiently and is then released. The mold also needs systems for material delivery, temperature control, alignment and part removal.

Draft is the taper applied to a surface relative to its direction of release from the mold. It helps reduce rubbing and damage during ejection. Suitable draft depends on feature depth, texture, resin and the tooling arrangement; it should be reviewed alongside the functional shape.

The parting surface is the interface where mold sections meet. The parting line is its visible boundary on the molded part. Choosing that interface affects how features are formed and released, as well as the location of a witness line on visible or functional surfaces.

Mold shrinkage describes how a molded part becomes smaller than the cavity dimensions as the material cools and stabilizes. The expected change depends on resin grade, part geometry and processing conditions. Tool dimensions use an appropriate allowance; a single percentage cannot describe every material and feature.

The gating or feed system carries molten plastic from the machine nozzle toward the cavities. A conventional cold-runner layout uses a sprue, runners and gates. Its layout influences pressure loss, filling balance and material usage, so it must be designed with the resin and cavity arrangement.

A gate is the opening through which plastic enters the cavity. Options include edge or tab gates, tunnel gates and hot-runner gate arrangements. The choice affects filling, gate removal and the remaining mark. Selection depends on resin, геометрия, appearance requirements and the proposed production method.

Cooling channels carry a temperature-control medium through the mold to remove heat and manage tool-surface temperature. Channel layout and fluid flow influence temperature differences and cooling consistency. The cooling plan should be considered with the cavity shape, resin and production cycle rather than added after the tool layout is fixed.

The ejection system applies the force needed to release the molded part after the tool opens. Ejector location and contact area affect how that force is distributed and where marks may remain. Review ejection together with draft, resin behavior, supporting geometry and cosmetic requirements.

The guiding system uses components such as leader pins and matching bushings to bring mold sections into alignment. These are mold components, distinct from the molding machine platens. Their fit and wear condition matter to repeatable registration of the cavity and core during repeated opening and closing.

Venting features provide escape routes for air and gases displaced as plastic fills the cavity. Effective venting helps limit trapped gas, burn marks and incomplete filling. The vent layout should be considered with the filling pattern and the locations where air is likely to become trapped.

A slide is a movable mold component that can form a side hole or undercut and then withdraw so the part can be released. Its movement is commonly transverse to the main opening direction. Slides are one tooling solution; not every undercut requires the same release mechanism.

Surface finish describes the polish or texture specified for a mold surface and the resulting appearance expected on the part. Resin, color and fillers also influence that appearance. Identify the surfaces and finish reference, then agree how representative molded samples will be judged rather than relying on a broad word such as glossy.