Polymer Selection and Injection-Molding Design Science

Compare automotive thermoplastics using stiffness, impact performance, service temperature, moisture sensitivity, shrinkage, chemical resistance, dielectric behavior where relevant, mass, cost, and appearance data.

Select a polymer with a weighted decision matrix tied to component requirements and manufacturing risks.

Estimate injection-molding cooling time using a one-dimensional heat-transfer model and stated thermal assumptions.

Calculate required mold clamp force from projected area, cavity pressure, cavity count, and a safety margin.

Select nominal wall thicknesses and design gradual wall transitions using a 3:1 transition guideline.

Size ribs, gussets, screw bosses, and insert features using DFM rules, including a rib-to-wall ratio no greater than 0.5 where visible-surface sink governs.

Determine minimum draft angles from pull direction, draw depth, surface texture, and polymer shrinkage.

Diagnose likely sink, weld-line, short-shot, air-trap, shrinkage, and warpage defects from part geometry, gate strategy, and process conditions.