Addressing the cross-leakage issue between the cylinder head cover’s threaded holes and angled oil passages by incorporating extrusion pins.
1. Project Background
In a die-casting project for an automotive engine cylinder head cover, the initial die casting mold and production process were developed by another supplier.
During the pilot production stage, a serious leakage issue was identified during the air leak test after machining.
The inspection results showed that:
Leakage occurred between the threaded hole and the inclined oil passage.
Statistical data from leak testing indicated that the defect rate reached:
41.2%.
To ensure the sealing performance of the product, the original production process required an impregnation process to reduce leakage risks.
Later, RaidyMold was invited to evaluate the existing casting process and tooling design, and to develop an optimized solution to improve this defect from the source.
2. Problem Description
After machining, the parts were subjected to an air leak test, where leakage was detected between the threaded hole and the inclined oil passage.
The issue manifested as:
- Leakage during air pressure testing
- Failure to meet sealing requirements
- A defect rate as high as 41.2%
This defect became the major factor affecting product quality stability.
3. RaidyMold Optimization Solution
To address this issue, Raidy Mold developed an optimized solution based on the original supplier’s design, focusing on improving the internal quality of the critical area through casting and tooling modifications.
The optimization included the following improvements.
3.1 Casting Structure Optimization
The original casting design was modified as follows:
- Removal of the pre-cast threaded hole
- Addition of a squeeze process boss
The added squeeze boss provides the structural condition required for implementing the local squeeze process during die casting.
3.2 Tooling Optimization
A squeeze pin was added to the die casting mold.
During the die casting process, the squeeze pin applies local pressure on the squeeze boss area.
This helps improve the internal density of the critical region and reduce the formation of casting defects.
4. MAGMA Simulation Comparison
To verify the effectiveness of the optimization, the squeeze process was added to the original supplier’s design and evaluated using MAGMA simulation software.
The simulation results showed that:
After introducing the squeeze process, the porosity and shrinkage defects in the critical area were significantly reduced.
The results confirmed that the squeeze process effectively improves the internal quality of the defect region.
5. Squeeze Process Parameter Optimization
The effectiveness of the squeeze process depends heavily on the process parameters.
Two critical parameters include:
- Squeeze start time
- Squeeze duration
Since these parameters are difficult to determine accurately based on experience alone, MAGMA parameter optimization function was used to optimize the process parameters.
A range of values for squeeze start time and squeeze duration was defined, and Porosity was selected as the optimization objective.
6. Optimization Evaluation
Multiple simulation scenarios were evaluated.
The results indicated that:
Scheme 10 ranked first in the overall evaluation.
Considering the actual performance of the die casting machine and production stability, the final production parameters were selected between Scheme 9 and Scheme 10.
7. Production Validation
After implementing the optimized solution, production trials and inspection results demonstrated significant improvement.
7.1 Leakage Improvement
After adding the squeeze pin, the leakage issue was significantly improved.
The defect rate was reduced from:
41.2% to 3.6%.
The leakage between the threaded hole and the inclined oil passage was essentially resolved.
7.2 Internal Quality Verification
By cutting and comparing the old and new castings, it was found that:
After introducing the squeeze process, the porosity and shrinkage defects in the critical area were significantly reduced, and the internal structure became more compact.
8. Final Results
Through the optimization solution developed by RaidyMold, the project achieved significant improvements in cost, process efficiency, and product quality.
8.1 Cost Savings
During the pilot production stage before optimization, an impregnation process was required to address the leakage issue.
After implementing the RaidyMold optimization solution, this process was eliminated.
Based on the following production conditions:
Monthly production volume:
20,000 pieces
Defect rate reduction:
41.2% → 3.6%
The annual cost savings reached approximately:
1.02 million RMB.
8.2 Process Optimization
After eliminating the impregnation process:
- The production process was simplified
- Production efficiency improved
- Material turnover time was reduced
8.3 Quality Improvement
Through the optimization of the die casting process, the internal quality of the product was significantly improved.
The sealing performance became more stable, and the OEE (Overall Equipment Effectiveness) of the production line was also improved.
8.4 Development Cycle Reduction
Through simulation analysis and process optimization, the number of mold trials and adjustments was reduced.
As a result, the overall project development cycle was shortened by:
42 days.
9. RaidyMold Engineering Capability
This case demonstrates RaidyMold’s engineering capability in die casting tooling development and process optimization, including:
- Die casting defect analysis
- Die casting process optimization
- Squeeze process design
- MAGMA simulation capability
- Process parameter optimization
- Engineering validation from simulation to production
RaidyMold not only provides die casting molds, but also delivers systematic engineering solutions to help customers solve complex production issues, improve product quality, reduce manufacturing costs, and enhance production efficiency.
