Die Casting Surface Finishing Services
Integrated surface treatment and secondary CNC machining for aluminum, zinc and magnesium die cast parts. Powder coating, anodizing, plating and precision post-machining under one roof, with third-party inspection and EN 10204 3.1 material certificates available on request.
Free Consultation24h
Rapid Quote
500 pcs
MOQ
±0.05mm
Post-Machining Tolerance
40-80μm
Coating Thickness
Materials
| Grade | Properties | Typical Applications |
|---|---|---|
| Aluminum A380 | Tensile strength 324 MPa, density 2.71 g/cm³, excellent fluidity and pressure tightness, good corrosion resistance, easy to cast thin walls | Automotive brackets, electronics housings, appliance bases, connector bodies |
| Aluminum A356-T6 | Tensile strength 275 MPa as-cast / 310 MPa T6, density 2.68 g/cm³, heat treatable for higher strength, good weldability | Structural parts, wheel hubs, suspension brackets, load-bearing frames |
| Aluminum A413 | Tensile strength 296 MPa, density 2.66 g/cm³, best castability and pressure tightness, thin-wall capable | Pump bodies, valve housings, transmission cases, fluid connectors |
| Zinc Alloy Zamak 3 | Tensile strength 283 MPa, density 6.60 g/cm³, superior dimensional stability and impact strength, easy to plate | Hardware, locks, connectors, decorative trims, small mechanical parts |
| Zinc Alloy Zamak 5 | Tensile strength 328 MPa, density 6.70 g/cm³, higher hardness and creep resistance than Zamak 3 | Gearbox covers, mechanical frames, tool bodies, precision mechanisms |
| Magnesium AZ91D | Tensile strength 230 MPa, density 1.81 g/cm³, lightweight with EMI shielding, good damping, corrosion protected by conversion coating | 3C electronics, brackets, drone and automotive lightweight parts |
Process Parameters
| Parameter | Standard Range |
|---|---|
| Casting Wall Thickness | 0.8 - 5.0 mm |
| As-Cast Surface Roughness | Ra 1.6 - 3.2 μm |
| Post-Machining Dimensional Tolerance | ±0.05 mm (ISO 2768-f) |
| Porosity (X-ray Class 2) | ≤ 3% by volume |
| Die Casting Machine Tonnage | 280 - 1600 T (cold chamber) |
| Max Part Weight (Cold Chamber) | up to 8 kg |
| Draft Angle (Minimum) | 1 - 3° per side |
| Powder Coat Film Thickness | 40 - 80 μm |
| Plating Thickness | 5 - 25 μm |
| Tooling Steel | H13 (production dies) |
Surface Finishes
Powder Coating
Durable thermoset film 40-80 μm with RAL and custom color matching and salt spray resistance 500-1000 h. Electrostatic spray covers complex geometries uniformly, then cured at 180-200°C for a chip-resistant finish on housings and brackets.
Anodizing (Type II / III) for Aluminum
Type II sulfuric anodize 5-25 μm with dye or natural finish; Type III hard coat 25-100 μm for abrasion resistance. Sealing performed to ASTM B580 for stable, corrosion-resistant appearance on A380 and A356 parts.
Zinc / Chrome Plating
Nickel undercoat plus decorative chrome or matte zinc for Zamak parts, thickness 5-25 μm with blue, black or colored passivation. Provides bright appearance and base corrosion protection per ASTM B456.
Electrophoretic Coating (E-Coat)
Cathodic epoxy film 15-35 μm with full coverage on recessed and internal features, excellent corrosion base under a powder or liquid topcoat. Ideal for parts with complex internal channels.
Bead / Shot Blasting
Uniform matte texture that hides minor as-cast flow marks. Glass bead or steel shot media delivers a consistent Ra 1.6-3.2 μm cosmetic finish before coating or as a standalone look.
CNC Post-Machining
Drilling, tapping, milling and boring of features not castable, including cross holes, threads and sealing faces, held to ±0.05 mm. Keeps critical dimensions tight where the casting process cannot reach.
Passivation (Magnesium)
Chrome-free conversion coating for AZ91D parts to slow corrosion before painting or assembly. Required for magnesium parts exposed to humidity or handled during production.
Design for Manufacturing (DFM)
- Keep wall thickness uniform between 0.8 mm and 2.5 mm to control porosity at finished surfaces
- Design flat locating datums on the casting so post-machining fixturing stays repeatable
- Avoid blind threads shorter than 1.5× diameter; cast the hole and tap after casting
- Provide 0.2-0.5 mm machining allowance on critical sealing and mating faces
- Add 1-3° draft on all vertical surfaces so coating and ejection stay clean
- Specify fillet radii of 0.5 mm or larger to reduce coating build-up at edges
- Place appearance surfaces away from parting lines to keep coating uniform
- Keep thin magnesium sections above 1.2 mm to avoid hot cracking during casting
- Reserve 0.1-0.2 mm per side for plating or anodize thickness in the finished dimension
- Upload STEP/IGES and get a free DFM report within 24h covering wall, draft, gates and finish
Tooling & Capacity
| Type | Lead Time | Suitable For |
|---|---|---|
| Prototype Die (Soft) | 2 - 3 weeks | 500 - 2,000 pcs validation, design confirmation, market testing |
| Production Die (H13) | 4 - 6 weeks | 5,000+ pcs, long-run production with stable dimensions |
| Multi-Cavity Die (4 - 8) | 6 - 8 weeks | High-volume runs requiring short cycle times |
| In-House Finishing Line | Integrated with casting | Coating, plating and post-machining of cast parts under one quality plan |
Quality Assurance
- Incoming alloy verification with mill certificates and EN 10204 3.1 material certificates per batch
- In-process X-ray porosity grading and dimensional spot checks during casting
- CMM inspection of machined features against the 3D CAD model
- Coating thickness measured by magnetic or eddy-current gauge at defined points
- Coating adhesion tested by cross-cut (ISO 2409) and bend before shipment
- Salt spray testing (ASTM B117) on finished samples per customer requirement
- Plating thickness and passivation verified per ASTM B456 and ISO 2081
- First Article Inspection report with full dimensional data before production release
- Batch dimensional and finish report shipped with every production lot
- Our quality system is documented and controlled in house; independent SGS, BV or TUV inspection, CMM reports and EN 10204 3.1 material certificates are available on request for finished cast parts
Applications
- Automotive: brackets, sensor housings, mirror frames, transmission parts
- Consumer electronics: heat sinks, frames, connector shells
- LED lighting: enclosures, heatsink housings, lamp bodies
- Power tools: gearbox covers, motor end caps, tool bodies
- Telecom: RF shields, connector blocks, enclosures
- Industrial: pump bodies, valve covers, metering housings
- Furniture and hardware: locks, handles, decorative trims
- Robotics: lightweight joints, link brackets, sensor mounts
- 3C and drone: magnesium brackets, camera frames, EMI shields
Why Choose FHY Precision
Single-source casting plus finishing cuts logistics and lead time versus split suppliers
Integrated post-machining means threaded and sealed features arrive ready to assemble
Documented quality system with third-party inspection and material certificates on request
Flexible tooling: prototype soft dies for 500 pcs, H13 production dies for volume
Free DFM report within 24h covering wall, draft, gates and finishing strategy
Factory-direct pricing straight from our own plant in China
Multiple coating systems in-house: powder, anodize, plating, E-coat, blasting
MOQ 500 pcs with scalable capacity from 280 T to 1600 T cold-chamber machines
FAQ
1. What is the minimum order quantity (MOQ) for die casting with surface finishing?
Our die casting MOQ is 500 pieces. A soft prototype die supports 500-2,000 pieces for validation, and production tooling (H13 steel) scales to 5,000 pieces and beyond. Surface finishing and post-machining are quoted together with the casting so you receive a finished, ready-to-assemble part rather than a raw casting.
2. Which die cast alloys can you finish and machine?
We finish and post-machine aluminum (A380, A356-T6, A413), zinc alloys (Zamak 3, Zamak 5) and magnesium (AZ91D). Aluminum parts suit anodizing and powder coating, zinc parts suit plating and powder coating, and magnesium parts receive a chrome-free conversion coating before painting. Material certificates are available per batch.
3. Do you provide a free DFM analysis before we commit to tooling?
Yes. Upload your STEP or IGES file and we return a free DFM report within 24 hours. For die cast parts the report covers wall thickness, draft angles, gate and runner position, and which surfaces need machining or coating. This review frequently prevents porosity and finish problems before any steel is cut.
4. How long does die casting tooling take?
Soft prototype dies take 2-3 weeks and support 500-2,000 pieces. Production dies in H13 steel take 4-6 weeks. Multi-cavity dies (4-8 cavities) take 6-8 weeks and are used for high-volume runs with short cycle times. Finishing line setup is integrated so it does not add separate lead time.
5. What surface finishing options do you offer for die cast parts?
Powder coating (40-80 μm), anodizing Type II and Type III for aluminum, nickel and chrome plating for zinc, electrophoretic E-coat, bead or shot blasting, and CNC post-machining. Most parts combine a coating with post-machining so threaded and sealing features meet tolerance while the visible surfaces meet appearance specs.
6. Can you supply samples before mass production?
Yes. We provide T1 samples from the first tooling trial for dimensional and finish approval, then refine the die before release. Many customers validate the design with a short sample run, confirm the coating and machining, and move straight into production with the proven tool and process.
7. How do you handle quality verification and inspections?
Our quality system is documented and controlled in house. On request we arrange independent third-party inspection by SGS, Bureau Veritas or TUV at any stage, plus CMM measurement reports and EN 10204 3.1 material certificates. You receive a neutral verification of dimensions, material and appearance before parts leave the factory.
8. How do you ensure consistent quality on finished die cast parts?
We verify incoming alloy with mill certificates, run in-process X-ray porosity grading and dimensional checks during casting, and inspect machined features by CMM against the 3D model. Coating thickness, adhesion (cross-cut per ISO 2409) and salt spray (ASTM B117) are tested before shipment, and a batch report ships with every lot.
9. What powder coating colors and thicknesses are available?
Powder coating is applied at 40-80 μm with full RAL color matching and custom colors. Curing runs at 180-200°C for a chip-resistant film with salt spray resistance of 500-1000 hours depending on the system. Texture ranges from smooth gloss to fine matte, and thickness is verified by gauge at defined points on each part.
10. Can you anodize aluminum die cast parts?
Yes. We offer Type II sulfuric anodize at 5-25 μm in dyed or natural finish, and Type III hard coat at 25-100 μm for wear resistance. Anodizing suits A380 and A356 housings and brackets, and sealing is done to ASTM B580 for stable corrosion resistance. Note that anodize builds dimension, so we reserve 0.1-0.2 mm per side in the finished size.
11. What plating options do you offer for zinc die cast parts?
Zamak parts receive a nickel undercoat plus decorative chrome or matte zinc, 5-25 μm thick, with blue, black or colored passivation per ASTM B456 and ISO 2081. Plating gives a bright, durable appearance and a corrosion base, and thickness is mapped across features to confirm uniform coverage on complex shapes.
12. Can you perform CNC machining after die casting?
Yes. Our in-house CNC post-machining adds drilling, tapping, milling and boring for features that cannot be cast, such as cross holes, threads and sealing faces, held to ±0.05 mm (ISO 2768-f). Because machining is integrated with casting and finishing, one purchase order covers the whole part and a single quality plan keeps dimensions compatible.
13. How do you test coating adhesion and corrosion resistance?
Adhesion is verified by cross-cut (ISO 2409) and bend tests before shipment. Corrosion resistance is confirmed by salt spray testing to ASTM B117 on finished samples, with 500-1000 hours typical for powder systems depending on film thickness and pretreatment. We report the actual tested result rather than a generic claim.
14. What tolerance can you hold after post-machining?
Post-machined features are held to ±0.05 mm, matching ISO 2768-f general tolerances, with tighter limits possible on critical sealing faces by agreement. The casting supplies the near-net shape and machining only cleans up datums, threads and mating surfaces, which keeps cost down versus full machining from solid.
15. What is the lead time for casting plus finishing plus machining?
After tooling is ready, typical turnaround is 2-4 weeks for the first finished lot depending on quantity, coating system and machining scope. The finishing line is in-house so coating and post-machining do not add separate supplier lead time. Every quotation includes a confirmed delivery date and the free DFM review is done within 24 hours of receiving CAD files.
16. Do you ship die cast finished parts internationally?
Yes, we ship worldwide by DHL, FedEx, UPS and sea freight. Finished parts are packed with anti-rust protection, foam-lined boxes and vacuum sealing where required. Every shipment includes a packing list, Certificate of Origin, commercial invoice and the batch inspection report, and air express to the US and Europe typically takes 3-7 days.