| Material | Shrinkage | Mold Steel | Vent Depth | Corrosion Risk | | :--- | :--- | :--- | :--- | :--- | | | Low | P20 (standard) | 0.03mm – 0.05mm | Low | | PC (Polycarbonate) | Low | H13 / Stainless | 0.02mm – 0.03mm | Low (requires dry steel) | | PVC | High | Stainless (420) | 0.01mm – 0.02mm | High (releases HCl gas) | | POM (Acetal) | High | P20 / H13 | 0.01mm | Moderate (degassing needed) | | Glass-filled Nylon | Low | Hardened H13 | 0.02mm (abrasive) | Low (abrasive wear on gates) |
Injection molding is the undisputed king of high-volume plastic part production. It allows manufacturers to create complex geometries with tight tolerances at a remarkably low cost per unit. However, the difference between a part that pops perfectly out of the mold every 30 seconds and one that warps, sinks, or cracks is entirely determined before the steel is cut. injection mold design guide
Remember: "It looks good on the computer" is not the same as "It ejects reliably on a cycle." | Material | Shrinkage | Mold Steel |
Implement these principles early, run a mold flow analysis, and respect the polymer. Your reward will be shorter lead times, lower tooling costs, and parts that fit right the first time. Need a downloadable checklist? Review sections 9 and 4 to create your internal design review form. Remember: "It looks good on the computer" is