CNC Machining for Die Casting Parts -Integrated, In-House, Precise

Die casting produces near-net-shape components -but most engineering applications require features that cannot be formed during the casting process itself. Precisely bored bearing seats, tapped fastener holes, flat sealing faces, fine thread forms, and tight-tolerance mating surfaces all require post-casting CNC machining.

KastMfg's integrated machining center operates within the same facility as our die casting production. Parts transfer from the casting floor to CNC without leaving the building -eliminating inter-supplier transit damage, reducing total lead time, and keeping dimensional accountability with one team.

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CNC Machining Capabilities

Operation	Equipment & Specification
3-axis CNC milling	VMC up to 1,000 x 600 x 500 mm working envelope
4-axis CNC milling	Rotary table, suitable for complex multi-face machining
5-axis simultaneous CNC milling	Full simultaneous 5-axis for complex sculptured surfaces and compound angles
CNC turning / lathe	Chuck capacity up to Ø500 mm; 800 mm between centers
CNC drilling & tapping	Auto tool change; tapping to M30; drilling to Ø50 mm
CNC boring	Precision bore to H6/H7 tolerance (bearing seats, bushing bores)
Thread milling	Large-diameter or precision thread milling (alternative to tapping)
Flatness grinding	Surface grinding for sealing faces; flatness to 0.01 mm achievable
Robotic deburring	Automated deburring for high-volume programs

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Typical CNC Operations on Die Castings

Fastener and assembly features

• Drilling and tapping of M3-M30 fastener holes
• Countersinking, counterboring, spot facing
• Helicoil insert preparation

Precision mating surfaces

• Face milling of parting surfaces, flange faces, and sealing surfaces
• Flatness to 0.02 mm on hydraulic manifold faces
• Step milling of locating datum surfaces

Bores and shafts

• Precision boring of bearing seats to H6/H7 (±0.005-0.015 mm)
• Bushing bores, shaft bore alignments
• Inner diameter turning on cast hubs and flanges

Complex geometry

• 5-axis milling of compound-angle features
• Pocket milling of internal features not formable by casting
• Profile milling of sealing grooves and O-ring channels

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Tolerances Achievable

Feature Type	Achievable Tolerance
General milled dimensions	±0.05 mm
Precision bores (H6/H7)	±0.005-0.015 mm
Threaded hole position	±0.1 mm true position
Flatness (sealing faces)	0.01-0.02 mm
Surface roughness (milled)	Ra 0.8-1.2 μm
Surface roughness (ground)	Ra 0.2-0.8 μm

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Why In-House Machining Matters

Dimensional traceability from casting to machined part When the same team casts and machines your part, datum selection, fixturing, and machining allowances are designed together -not negotiated between two separate suppliers. KastMfg's tooling engineers design casting datum features and machining fixtures simultaneously, ensuring that machining references are cast accurately and machined repeatably.

Faster response to drawing changes Engineering changes that affect both casting geometry and machined features are handled by a single project engineer. Drawing revisions are implemented in both the die and the CNC program without the coordination delays that arise between separate suppliers.

Reduced logistics risk Raw castings are fragile in transit -flash, fins, and thin features break; surfaces get scratched. Machining in-house eliminates one inter-supplier shipment, one customs clearance, and one handling cycle. The part that reaches your dock is finished, inspected, and packaged -not a partially processed subassembly requiring further work.

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Inspection After Machining

All machined features are inspected before shipment:

• CMM (coordinate measuring machine) inspection for critical dimensions and GD&T features
• Surface roughness measurement on sealing faces and precision bores
• Thread gauging (go/no-go) on all tapped holes
• Visual inspection for burrs, tool marks, and surface defects
• Dimensional reports included with every first article and available on request for production shipments

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Industries and Applications

Industry	Typical Machined Parts
Automotive	Gearbox housings (bore + bearing seats + sealing faces), motor end shields, caliper bodies
Industrial Hydraulics	Manifold blocks (port drilling + face milling + thread milling), pump housings
Electronics	Heat sink bases (flatness ground), connector housings (thread tapping)
Industrial Automation	Robot arm links (multi-face 5-axis), end-of-arm tooling bodies

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Frequently Asked Questions

Can you machine hardened inserts within a die casting?

Yes. For wear surfaces or threaded features requiring higher hardness than the casting alloy provides, steel inserts can be cast-in during die casting and then precision-machined after casting. We design and supply the inserts as part of the complete component.

What is your machining capacity for high-volume programs?

Our 18 CNC machining centers operate on two shifts. Current capacity is approximately 250,000 machining operations per month across all machines. For programs requiring dedicated capacity, we discuss capacity reservation during program launch planning.

Do you offer CNC machining for parts not made at KastMfg?

Our primary focus is integrated casting-to-finished-component programs. For standalone machining of externally sourced castings, contact us to discuss scope and capacity availability.

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CNC machining inquiry: yaoqingpu1983@gmail.com | +86 138 1403 4409 | No.6, Rungu Road, Nanjing, China