Every lighting housing, furniture hinge, and automotive bracket begins as a raw aluminum alloy.
Yet, few buyers understand the engineering discipline behind transforming molten metal into dimensionally precise parts.
At Yongzhu Casting, every component follows a controlled manufacturing chain — from high-pressure die casting (HPDC) to CNC precision finishing — ensuring mechanical reliability and consistent appearance for OEM applications.
Understanding this process helps buyers evaluate design feasibility, cost drivers, and supplier capability before mass production.
Alloy Selection & Melting
The process begins with choosing the right alloy.
For aluminum spare parts, A380, ADC12, and AlSi9Cu3 are industry standards because they balance flowability, strength, and corrosion resistance.
Once selected, aluminum ingots are melted at 660 – 700 °C in a crucible furnace.
Any oxide film or slag is skimmed off to maintain chemical purity.
Temperature accuracy here matters:
- If too low, the metal won’t fuse properly and causes cold shuts or flow marks.
- If too high, gas absorption and porosity increase.
High-Pressure Die Casting (HPDC)
Injection & Fill
Molten aluminum is injected into a steel die cavity at 80 – 120 MPa, sometimes reaching 175 MPa for thin-wall parts.
Cycle times range from 30 – 60 seconds per shot, depending on size and wall thickness.
Solidification & Cooling
Within milliseconds, aluminum solidifies under pressure.
Uniform cooling prevents shrinkage cavities and ensures a fine grain structure for strength and surface precision.
Ejection & Trimming
Ejector pins release the solidified casting.
Runners and flash are trimmed automatically before machining.
Proper draft angles (1–3°) and vent design guarantee clean ejection and prevent gas entrapment.
Process Parameters That Define Casting Quality
| Parameter | Typical Range | Effect on Quality |
|---|---|---|
| Molten Aluminum Temperature | 660 – 700 °C | Too low → cold shuts; too high → porosity |
| Die Temperature | 180 – 220 °C | Low → flow marks; high → mold wear |
| Injection Pressure | 80 – 120 MPa | Affects density, surface smoothness |
| Fill Time | 20 – 50 ms | Too fast → turbulence; too slow → misrun |
| Holding Pressure Duration | 10 – 30 ms | Ensures compaction and minimal voids |
These data are verified across Dynacast, Sunrise Metal, and ASM references, forming the baseline for stable HPDC operations.
CNC Machining: Achieving Precision Beyond Casting
Even with HPDC’s accuracy, secondary machining is essential for tolerance control.
Main Operations
- Milling: Planar surfaces, slots, and bosses
- Turning: Shafts and cylindrical features
- Drilling & tapping: Threaded holes for assemblies
- Reaming & deburring: Surface refinement and fit accuracy
Modern machining centers operate between 1 000 – 4 000 RPM, depending on alloy hardness and tool geometry.
For standard aluminum die castings, tolerances of ± 0.05 – 0.2 mm are achievable with rigid fixturing.
Every part undergoes CMM (Coordinate Measuring Machine) inspection to verify dimensional stability.
Leak-test and surface porosity checks follow before finishing.
Case Study: Aluminum Bracket for LED Floodlight Housing
A 1.2 kg ADC12 aluminum bracket was produced using an 800 T HPDC machine.
- Cycle time: 45 s
- Porosity: < 0.5 % after pressure holding
- Machining: M8 threaded holes, tolerance ± 0.05 mm
- Finish: Powder coating RAL 9016 white
- Salt-spray resistance: 240 h without corrosion
This project demonstrates how close control of casting temperature, fill rate, and die balance ensures consistent appearance and performance under outdoor conditions.
Surface Finishing: Function & Aesthetics Combined
Surface treatment not only beautifies aluminum parts but also protects them from oxidation, UV exposure, and moisture.
| Finishing Type | Key Benefit | Applications |
|---|---|---|
| Anodizing | Forms a hard oxide layer, customizable color | Lighting housings, electronics |
| Powder Coating | Corrosion and UV resistance | Furniture hardware, outdoor brackets |
| Shot Blasting / Polishing | Smooth or matte surface texture | Decorative trims, consumer parts |
| Chromate Conversion | Primer layer for paint adhesion | Automotive engine parts |
All coatings undergo salt-spray (ASTM B117) and adhesion testing to validate real-world durability.
Assembly, Testing & Export Packaging
Quality assurance closes the loop between design and delivery.
Verification Tests
- CMM dimensional checks
- Leak or pressure testing for enclosures
- Visual surface inspection under LED light
- Porosity review using dye-penetrant methods
Packaging & Logistics
Before export, components are packed in:
- Anti-static liners
- Moisture-barrier bags
- English-labeled cartons, stacked on ISPM-certified pallets
This ensures parts arrive clean, corrosion-free, and ready for assembly worldwide.
Sustainability Through Closed-Loop Recycling
Yongzhu Casting primarily uses certified new aluminum ingots to guarantee alloy consistency and mechanical strength.
During die casting, internal runners, overflow parts, and defective castings are remelted in-house under controlled ratios — a closed-loop recycling practice that reduces waste without compromising metal chemistry.
This internal reuse conserves energy, lowers material cost, and supports sustainable manufacturing —
without using any external or post-consumer recycled aluminum.
Real-World Applications
Lighting Industry
Die-cast aluminum housings provide excellent heat dissipation and meet IP65–67 sealing for industrial LED fixtures.
Furniture Hardware
Aluminum door handles and cabinet pulls combine light weight with high surface versatility, supporting anodized, brushed, or painted finishes.
Automotive & Machinery
From engine brackets to steering-column mounts, HPDC parts offer tight tolerance integration and superior vibration resistance.
Why Buyers Should Understand the Process
For OEMs, knowing the manufacturing chain means more control over:
- Design for Manufacturability (DFM): optimized wall thickness, draft, gating
- Cost Drivers: cycle time, machining load, surface treatment
- Reliability: integrated HPDC + CNC + testing ensures uniform quality
- Traceability: ISO 9001 and process data logging enable full audit compliance
A transparent workflow translates directly into predictable product performance.
Partner with Yongzhu Casting
From alloy melting to export packaging, every stage at Yongzhu is documented, measured, and optimized.
Our engineers can review your 3D drawings and RFQ for draft, gating, and wall-thickness feasibility before tooling begins — minimizing iteration time and startup risk.
Ready to bring your aluminum spare parts to life?
Share your RFQ today — we’ll provide technical feedback and quotation within 48 hours.
