Die casting is one of the most efficient and precise methods for producing aluminum automotive components.
But even in well-controlled environments, defects can occur.
Understanding the common die casting problems — and how to fix them — helps manufacturers improve yield, reduce waste, and ensure high-quality results.
Here are the top 10 die casting problems our engineering team at Wometal often encounters — and how we solve them.
1. Porosity (Air Bubbles or Voids)
Problem: Small holes or air pockets inside the casting caused by trapped gas or insufficient venting.
Solution:
- Improve mold venting and vacuum systems
- Control injection speed and temperature
- Use vacuum die casting or optimized gating design
2. Cold Shut
Problem: Two metal flows fail to fuse properly, creating a weak joint line.
Solution:
- Increase metal temperature or gate velocity
- Redesign runner system to improve flow
- Preheat the die evenly before casting
3. Shrinkage Cavities
Problem: Voids formed during solidification due to uneven cooling or insufficient feeding.
Solution:
- Optimize wall thickness and cooling rate
- Adjust injection pressure during solidification
- Add overflow or feeder design to prevent shrinkage
4. Flash Formation
Problem: Thin metal layer along parting lines or ejector pins.
Solution:
- Reduce injection pressure
- Ensure die halves close properly
- Inspect mold wear and replace seals as needed
5. Hot Tear (Cracking During Cooling)
Problem: Cracks appear when the part cannot contract freely during solidification.
Solution:
- Modify mold design to allow even cooling
- Use alloys with better ductility
- Optimize ejection timing and mold temperature
6. Incomplete Filling
Problem: Part not fully filled with molten metal, leaving voids or short shots.
Solution:
- Increase injection speed or metal temperature
- Optimize gate and runner dimensions
- Check air vents and shot sleeve condition
7. Surface Blisters or Bubbles
Problem: Gas trapped near the surface during solidification.
Solution:
- Improve venting and vacuum control
- Avoid moisture in die lubricant
- Reduce release agent quantity and injection speed
8. Ejector Marks or Pin Damage
Problem: Visible pin marks or deformations after ejection.
Solution:
- Optimize ejection pin layout and timing
- Reduce holding pressure before ejection
- Apply proper mold release lubricant
9. Sticking and Soldering
Problem: Molten aluminum sticks to die surface or welds to the mold.
Solution:
- Apply die coating and increase mold temperature
- Adjust alloy composition (reduce iron content)
- Polish die surface to reduce adhesion
10. Warping and Deformation
Problem: Distortion due to uneven cooling or internal stress.
Solution:
- Design uniform wall thickness
- Use balanced cooling channels
- Perform post-casting heat treatment or CNC correction
How Wometal Prevents and Solves Die Casting Problems
At Wometal, we approach die casting quality control systematically:
- Mold flow simulation before production
- Vacuum die casting for improved density and strength
- CNC post-machining for dimensional accuracy
- CMM and visual inspection for each batch
- Continuous feedback between tooling, process, and QC teams
Our integrated CNC + die casting process ensures precision, repeatability, and long-term performance for automotive components.
Conclusion
Die casting defects are common — but with the right process control, they can be prevented or corrected.
By partnering with an experienced automotive die casting manufacturer like Wometal, you gain not only quality components but also engineering expertise that ensures long-term reliability.
👉 “Learn more about our automotive components.