After ejection from the die casting machine, parts typically require additional cutting operations to achieve final drawing specifications for dimensional accuracy and surface quality. We provide professional post-machining services – covering turning, milling, drilling, tapping, and grinding – ensuring that every casting meets customer technical requirements for critical dimensions, fit precision, and assembly performance.
What is Post-Machining？
Post-machining refers to precision cutting operations performed on castings after the die casting process. Compared to the as-cast state, post-machining achieves tighter dimensional tolerances and lower surface roughness – it is the critical step that transitions castings from “near-net shape” to “finished part.”
The Synergy Between Die Casting and Post-Machining
Die casting efficiently produces complex shapes, but certain critical features – such as precision holes, threads, sealing surfaces, and mounting faces – require post-machining to guarantee final accuracy. The two processes complement each other: die casting provides “near-net shape” blanks, while post-machining delivers “net shape” precision features.
Our Post-Machining Capabilities
Turning
- .CNC lathes
- .Operations: external diameter, internal bore, facing, stepped profiles, threading
- .Typical parts: rotational castings (motor housings, hubs, valve bodies)
- .Precision: ±0.01mm
Milling
- .3-axis / 4-axis / 5-axis CNC machining centers
- .Operations: flat surfaces, curved surfaces, slots, cavities, complex contours
- .Typical parts: irregular structural parts, housings, brackets
- .Precision: ±0.01mm
Drilling
- .Standard drilling, deep hole drilling (gun drilling)
- .Operations: through holes, blind holes, stepped holes, deep holes
- .Applications: oil galleries, cooling channels, mounting holes, dowel pin holes
Tapping
- .Rigid tapping / flexible tapping
- .Thread standards: Metric, UNC, UNF
- .Applications: threaded connection holes, sensor mounting holes, fitting ports
Reaming & Boring
- .High-precision hole finishing
- .Applications: dowel pin holes, bearing mounting holes, sealing mating holes
- .Precision: ±0.005mm (reaming achieves H7 tolerance)
Grinding
- .Surface grinding, cylindrical grinding, internal grinding
- .Applications: high-precision flat surfaces, shaft components, sealing faces
- .Precision: ±0.002mm
Why Post-Machining Matters
- .Achieves dimensional tolerances beyond die casting capability
- .Enables threaded connections, bearing fits, and sealing functions
- .Improves surface quality, enhancing appearance and durability
- .Corrects casting distortion, ensuring assembly consistency
- .Provides an ideal foundation for surface finishing (anodizing, painting, etc.)
Applicable Materials
.Aluminum alloys (ADC12 / A380), Magnesium alloys, Zinc alloys
| Feature Type | Operation | Typical Parts |
|---|---|---|
| Precision holes | Drilling / Reaming | Mounting holes, locating holes |
| Thread connections | Tapping | Sensor ports, fluid ports |
| Sealing surfaces | Milling / Grinding | End seal grooves, flange faces |
| Bearing seats | Boring / Grinding | Motor housing bearing bores |
| Complex contours | 5-axis milling | Structural parts, brackets |
| Oil/air channels | Deep hole drilling | Valve bodies, hydraulic parts |
Quality Control & Inspection
- First article full dimensional inspection (CMM)
- In-process inspection (SPC)
- Final inspection (dimensional report + visual inspection)
- Custom gauges and inspection fixtures
- Surface roughness measurement
Case Studies
| case | Part Type | Post-Machining Scope |
Precision Requirement |
Result |
|---|---|---|---|---|
| Case 1 |
EV motor housing |
Bearing bore boring + face milling + mounting hole drilling/tapping |
Bearing bore H7, position tolerance ± 0.05mm |
Passed PPAP first time |
| Case 2 |
Automotive ABS valve body |
Deep hole drilling + sealing face milling |
Hole depth ± 0.1mm, surface roughness Ra1.6 |
99.2% yield |
| Case 3 |
LED heatsink |
Mounting face milling + threaded hole tapping |
Flatness 0.03mm, thread gauges OK |
1000 pcs first batch, zero complains |
Why Choose Our Post-Machining Services？
- One-stop delivery – Casting and machining completed in one facility – reduces logistics and quality risks
- High precision – Machining accuracy up to ±0.01mm, meeting strict requirements of automotive, telecom, and medical sectors
- Flexible volumes – Efficiently handling everything from prototypes to high-volume production
- Full traceability – Batch data recorded and traceable, CMM inspection reports available
- Concurrent engineering – Machining strategy planned during mold design phase – optimized machining allowance and locating references
Contact us for a post-machining quote.
