PC + PA66 GF30 Overmolding Injection Mold Case

Challenge

Achieving reliable bonding between PA66+GF30 and PC while maintaining dimensional accuracy, preventing stress cracking, deformation, and surface damage on the large transparent component.

The main challenges included:

• Material compatibility:
  PA66 GF30 and PC have different shrinkage rates and thermal expansion characteristics, creating risks of poor adhesion, warpage, and cracking after molding.
• Transparent PC protection:
  The large-size transparent PC part required strict control to avoid scratches, stress marks, whitening, and surface defects during molding and demolding.
• Dimensional stability:
  The overmolding process needed to maintain precise dimensions while ensuring strong bonding between the two materials without internal stress or deformation.

Solution

XINKEY MOULD developed an optimized PC-PA66 overmolding solution through material selection, injection optimization, and mold structure improvement.

Key solutions included:

• Optimized material selection:
  Selected high-performance PC material with improved resistance to heat and stress cracking, ensuring better compatibility with PA66 GF30.
• Optimized injection system design:
  Improved gate location and filling balance to achieve stable melt flow, reduce internal stress, and ensure uniform bonding performance.
• Enhanced bonding structure design:
  Optimized the overmolding interface and parting line design to improve mechanical bonding strength and prevent separation between PC and PA66.
• Large transparent part protection:
  Developed a precision mold structure and optimized ejection system to prevent scratches, deformation, and damage to the transparent PC surface.
• Engineering validation:
  Completed mold testing successfully on the first trial, achieving customer requirements for validation and export-ready tooling.

Result

Successfully delivered a high-performance PC + PA66 GF30 overmolding mold with strong bonding, stable dimensions, and excellent transparent surface quality.

Results achieved:

• Strong adhesion between PC and PA66 GF30 with no delamination or cracking.
• Large transparent PC component molded without scratches, whitening, or surface defects.
• Stable product dimensions meeting customer validation requirements.
• First trial success reduced development risk and shortened project lead time.
• Mold approved as a reliable solution for future mass production.