Machining and Finishing of Castings
Most castings are not finished parts straight out of the die or shell. Precision faces, holes and threads are machined, gates and flash are removed, and a finish is applied. Huasheng Precision, which operates CastingSmith, is a CNC machining manufacturer; machining of castings is done in-house or with partners depending on the drawing.
Post-machining
| Operation | Typical features |
|---|---|
| Milling | Sealing faces, mounting faces, fits and steps |
| Drilling, reaming, tapping | Mounting holes, threads, locating holes |
| Turning | Bearing bores and cylindrical fits |
| Trimming and deburring | Gates, overflows and flash |
For castings, the choice of datums and how as-cast variation is handled matter most. Please show datums and machined surfaces clearly on the drawing.
Surface finishes
| Finish | Purpose | Notes |
|---|---|---|
| Shot blasting | Uniform surface, coating prep | Agree roughness and appearance standards |
| Powder coating / wet paint | Appearance, corrosion protection | Specify color (RAL etc.) and film thickness |
| Anodizing | Corrosion protection, appearance | High-silicon alloys such as A380 / ADC12 anodize grey and uneven |
| Chemical conversion coating | Paint base, electrical conductivity | Confirm type and restrictions (e.g. hexavalent-chromium-free) |
| Plating (zinc castings) | Decorative, corrosion protection | Porosity can show through; agree cosmetic standards first |
FAQ
Can A380 or ADC12 die castings be anodized?
They can be processed, but the high silicon content gives a grey, uneven appearance compared with wrought aluminum. If appearance matters, consider painting, or discuss alloy choice at the design stage.
Why combine casting and machining with one supplier?
Datums, root-cause analysis when something goes wrong, and logistics are handled in one place. Price depends on the job, so compare like-for-like quotes.