Manufacturing

Injection Molding in China: Complete Guide

TL;DR: China produces 60%+ of the world's plastic injection molded parts. Mold costs are 40–60% less than US/EU. Simple molds start at $1,500–$3,000; complex multi-cavity molds can reach $50,000+. Lead time: 3–6 weeks for mold making, then mass production at thousands of parts per day.

Why China for Injection Molding?

Mold Costs

Mold TypeCost Range (China)LifespanBest For
Prototype (aluminum)$1,500 – $5,0001,000–10,000 shotsTesting and validation
Production (P20 steel)$3,000 – $15,000100,000–500,000 shotsMedium-volume production
High-volume (H13 steel)$8,000 – $30,000500,000–1M+ shotsHigh-volume, long-term production
Multi-cavity$15,000 – $50,000+1M+ shotsVery high volume, maximizing output

Common Plastic Materials

MaterialPropertiesCommon Uses
ABSStrong, impact resistant, easy to paintElectronics housings, toys, consumer products
PC (Polycarbonate)Transparent, very strong, heat resistantLED covers, phone cases, safety equipment
PP (Polypropylene)Flexible, chemical resistant, food safeFood containers, bottle caps, living hinges
PA (Nylon)High strength, wear resistantGears, structural parts, automotive
TPU/TPESoft, rubber-like, flexiblePhone cases, grips, overmolding

Quality Control for Injection Molding

  1. T1 samples (first trial): Always request T1 samples from the new mold. Check dimensions, surface finish, and material quality.
  2. Dimensional inspection: Use calipers and CMM (Coordinate Measuring Machine) to verify critical dimensions match drawings.
  3. Material certification: Request material certificates (COA) from the resin supplier to verify grade and composition.
  4. Visual standards: Define acceptable levels for sink marks, flash, flow lines, and weld lines. Create a golden sample.
  5. Functional testing: Test assembled parts for fit, function, and durability before approving mass production.

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