📋 Quick Summary
Quality control is critical in injection mold manufacturing. ISO 9001 and industry-specific standards ensure consistent part quality, dimensional accuracy, and long mold life. This comprehensive guide covers all aspects of QC in mold production.

1. ISO 9001 Quality Management
Our ISO 9001 certified quality management system covers every stage from design to delivery. Documented procedures ensure consistency and traceability throughout the manufacturing process.
Key Quality Documents
- Design Review Records: DFM analysis, mold flow simulation reports, design validation
- Inspection Reports: First article inspection, in-process checks, final inspection data
- Material Certificates: Steel grade certification, heat treatment records, hardness reports
- Dimensional Reports: CMM measurement data, 2D/3D comparison results
- Process Documentation: Work instructions, quality control plans, traveler sheets
2. Dimensional Accuracy Standards
Precision molds require tight tolerances. We follow international standards for dimensional accuracy and surface finish to ensure part quality and mold longevity.
Typical Tolerances by Application
| Feature | Standard Tolerance | Precision Tolerance | Application |
|---|---|---|---|
| Part Dimensions | ±0.05mm | ±0.01mm | General / Precision |
| Core/Cavity | ±0.02mm | ±0.005mm | Mold components |
| Surface Finish | VDI 24 | VDI 12 (Mirror) | Visible surfaces |
| Shut-off Faces | ±0.03mm | ±0.01mm | Mold sealing |
| Ejector Pins | ±0.02mm | ±0.005mm | Part ejection |
International Standards We Follow
- DIN (German): DIN 16742 for plastic part tolerances
- ISO: ISO 20457 for injection molded parts
- SPI: Society of Plastics Industry surface finish standards
- VDI: VDI 3400 for textured surfaces
3. Inspection Equipment
Advanced metrology equipment ensures accurate measurement and quality verification. Our investment in state-of-the-art inspection technology enables precise quality control.
Our Inspection Capabilities
- CMM (Coordinate Measuring Machine): Zeiss and Mitutoyo systems for 3D dimensional inspection with ±0.002mm accuracy
- Optical Comparator: Profile and contour measurement for complex geometries
- Surface Roughness Tester: Ra, Rz surface finish measurement for texture verification
- Hardness Tester: Rockwell, Vickers hardness testing for material verification
- Video Measuring System: Non-contact 2D dimensional inspection
- 3D Scanner: Reverse engineering and part-to-CAD comparison
4. Material Quality Control
Mold steel quality directly impacts mold life and part quality. We use certified materials from reputable suppliers with full traceability.
Steel Certification Requirements
- Material grade certification (DIN, AISI, JIS standards)
- Heat treatment records and hardness reports
- Ultrasonic testing for internal defects
- Chemical composition analysis
- Country of origin documentation
Common Mold Steels We Use
| Steel Grade | Hardness | Application | Mold Life |
|---|---|---|---|
| P20 | 28-32 HRC | General purpose | 300K-500K shots |
| H13 | 48-52 HRC | High production | 500K-1M shots |
| S136 | 48-52 HRC | Corrosion resistant | 500K-1M shots |
| NAK80 | 37-43 HRC | High polish | 500K+ shots |
| Stavax | 48-52 HRC | Premium applications | 1M+ shots |
5. Process Quality Control
In-process inspection catches issues early, reducing rework and delays. Our multi-stage QC approach ensures problems are identified and resolved before they impact delivery.
Inspection Checkpoints
| Stage | Inspection Item | Method | Frequency |
|---|---|---|---|
| Design | DFM Review | Mold Flow Analysis | Every project |
| Material | Steel Verification | Certificate Review | Per batch |
| Machining | Critical Dimensions | CMM, Calipers | Per operation |
| Heat Treatment | Hardness | Hardness Tester | Per batch |
| Assembly | Fit & Function | Trial Assembly | Per mold |
| T0 Sample | Part Dimensions | CMM, Visual | Per cavity |
6. T0/T1 Sample Validation
First article inspection validates mold performance before shipment. Comprehensive T0 sample reports provide confidence in mold quality and production readiness.
T0 Sample Report Includes
- Dimensional Measurement Report (FAI): All critical dimensions with actual values
- Visual Inspection Photos: High-resolution images of samples from all cavities
- Material and Process Parameters: Resin type, molding conditions, cycle time
- Weight Comparison: Shot weight consistency across cavities
- Recommended Adjustments: Any modifications needed for optimal performance
7. Continuous Improvement
Quality doesn’t stop at inspection. Our continuous improvement program uses data from every project to enhance processes and prevent future issues.
Improvement Methods
- Root Cause Analysis: 5-Why analysis for any non-conformities
- Corrective Actions: CAPA system for systematic issue resolution
- Lessons Learned: Project reviews capture insights for future work
- Employee Training: Regular quality training for all team members
Conclusion
Quality control is not optional—it’s essential for mold performance and part consistency. Partner with suppliers who invest in quality systems, inspection equipment, and continuous improvement.
ISO 9001 Certified Quality
Tuohai Technology delivers molds with complete quality documentation!
📧 Email: [email protected]
📱 WhatsApp: +8613037600603
📍 Address: Rm. 2-2502, No. 63 Qinling Road, Zhengzhou, Henan, China



