Are high-demand die castings unstable? Vacuum die casting to solve
Have you also encountered this situation: the drawings are fine, the mold is opened normally and the process is in accordance with the process, but there is always something wrong with the die-casting parts you receive:
- There are bubbles in the appearance of the product;
- CT inspection showed that the internal pores were excessive;
- I want to do T6 heat treatment, but I am afraid of thermal expansion and cracking...
The more complex the structure and the thinner the wall, the more frequently quality problems occur. In fact, the problem may not be the injection curve, but the die-casting method itself.
This is why more and more projects with high consistency requirements are beginning to use Vacuum Die Casting to replace traditional HPDC to optimize air entrainment, pores and surface defects from the source.
Add a vacuum link to the standard HPDC process:
By reducing the gas content in the mold cavity before filling, reducing gas entrainment and turbulence, the aluminum can reach thin walls, deep cavities and end areas more smoothly, improving the density and consistency of castings.
By reducing air inclusions through vacuuming, most of the above defects are significantly alleviated, and the quality and consistency of castings are simultaneously improved.
| Category | Traditional Die Casting | Vacuum Die Casting |
|---|---|---|
| Melt Air in Cavity | More residual air and easy to entrap gas | Vacuuming before filling significantly reduces gas entrapment |
| Filling Characteristics | Easy to cause local turbulence and insufficient casting at the end | Smoother filling; easier to fill thin-walled/deep cavity parts |
| Density / Porosity | Relatively high porosity | Lower porosity and denser microstructure |
| Heat Treatment Adaptability | Higher risk due to gas pore influence | More suitable for heat treatments such as T6 |
| Surface and Post-processing | More repair, grinding and potting | Better surface; reduced machining allowance and fewer repairs |
| Application Scenarios | General structures with moderate requirements | High integrity / high consistency / thin-walled and complex parts |
The vacuum environment reduces the mixing of molten metal and air, significantly reduces internal pores and makes the density and mechanical performance more stable.
Surface defects such as peeling and cold insulation are reduced, the finish is better, and the workload of machining and polishing is reduced.
Negative pressure improves the filling of ends and details, supporting thinner and more delicate structural designs (1–2 mm).
After the pores are reduced, heat treatments such as T6 are more controllable, the hardness and toughness improvements are easier to reproduce.
As the yield increases, repairs and scraps are reduced, the overall manufacturing cost of medium batches is usually more advantageous.
(1) Medical equipment structural parts
Requires high cleanliness, low porosity, heat treatable
(2) Robot joints
Thin wall + load bearing, strict assembly tolerances
(3) Automobile lightweight structural parts
The bracket/casing pursues density + consistency + heat treatment
(4) Marine/communication electronic housing
High air tightness, corrosion resistance, strict surface quality before spraying
