CNC Machining for Die Casting | Post-Cast Precision Finishing
Die casting produces near-net-shape components with exceptional speed — but critical mating faces, bearing bores, threaded interfaces, and sealing surfaces demand the dimensional precision that only CNC machining can deliver. Marcus Hi-Tech’s in-house CNC machining capability is built specifically around post-cast finishing of aluminium, zinc, and magnesium die castings. From 3-axis milling to 5-axis simultaneous machining, we bridge the gap between raw casting and assembly-ready component — eliminating the logistics cost, quality risk, and lead time of outsourced post-processing. One supplier. Cast to finished. Ready to assemble.
How It Works
Step 1: Casting & Datum Establishment
Every die cast part arrives at our CNC cell with defined casting datums — reference surfaces cast directly into the die geometry. Our fixture engineers design custom jigs that locate the casting repeatably from these datums, ensuring positional accuracy is maintained across every machined feature throughout the production run.
Step 2: Toolpath Programming & Simulation
Our CAM engineers programme toolpaths directly from your 3D CAD model using Mastercam or equivalent software. Toolpath simulations verify clearances, cutting sequences, and cycle times before the first part is fixtured — eliminating crash risk and reducing first-off setup time significantly.
Step 3: Machining — 3-Axis to 5-Axis
Parts are machined on our CNC machining centres ranging from standard 3-axis vertical mills to full 5-axis simultaneous machining for complex compound-angle features. Operations include face milling, boring, reaming, drilling, tapping, and contour finishing — all in a single setup where possible to minimise datum shift between operations.
Step 4: CMM Inspection & Despatch
All critical features are inspected on our Coordinate Measuring Machines (CMM) against your 3D model or 2D drawing tolerances. Inspection reports are generated per batch and supplied with each shipment. GD&T callouts including flatness, perpendicularity, true position, and cylindricity are fully verified before any part leaves our facility.
Product
1. Aluminium Gearbox Housing — Machined
Model ID: MHT-AUTO-GBX-MCH
Industry: Automotive Powertrain
Description: High-pressure die cast aluminium gearbox housing with fully machined mating flanges, bearing bores, and oil seal seats. All critical interfaces are finish-machined to H7 bore tolerance and Ra 1.6 µm surface finish — ready for direct bearing press-fit and gasket sealing on the powertrain assembly line.
Technical Specifications:
- Material: Aluminium A380 HPDC
- Bore Tolerance: H7 (±0.012mm)
- Surface Finish: Ra 1.6 µm on sealing faces
- Operations: Face Mill + Bore + Ream + Tap
- Availability: High Volume OEM Supply
2. EV Motor End Cover — 5-Axis Machined
Model ID: MHT-EV-MCH-5AX
Industry: Electric Vehicles
Description: Low pressure die cast aluminium EV motor end cover requiring compound-angle coolant port drilling and precision bearing housing bores. 5-axis simultaneous machining completes all features in a single setup — eliminating datum shift errors that multi-setup 3-axis approaches introduce. Leak tested to 10 bar before despatch.
Technical Specifications:
- Material: Aluminium A360 LPDC
- Machining: 5-Axis Simultaneous
- Leak Test: 10 Bar hydraulic
- Positional Tolerance: ±0.02mm true position
- Availability: Series Production (MOQ: 1,000)
3. Zinc Die Cast Valve Body — Bored & Tapped
Model ID: MHT-HYD-VLV-MCH
Industry: Hydraulics & Fluid Control
Description: Cold chamber zinc die cast hydraulic valve body with fully machined internal flow bores, NPT/BSP threaded ports, and flat sealing faces. Near-net-shape casting minimises material removal — CNC machining adds only the precision port geometry and thread forms required for pressure-tight hydraulic connections.
Technical Specifications:
- Material: ZA-8 Zinc Alloy
- Thread Forms: NPT / BSP to drawing
- Sealing Faces: Ra 0.8 µm flatness
- Pressure Test: 25 Bar post-machining
- Availability: Custom Production Runs
4. Aerospace Bracket — CMM Certified
Model ID: MHT-AER-BKT-CMM
Industry: Aerospace & Defence
Description: Gravity die cast aluminium aerospace mounting bracket with 5-axis machined hole patterns, countersinks, and datum reference surfaces. Every part is 100% CMM inspected against AS9100 first article requirements. Full dimensional report, material certificate, and process traceability record supplied with each batch.
Technical Specifications:
- Material: Aluminium A356-T6 GDC
- Inspection: 100% CMM per part
- Documentation: AS9100 First Article Report
- GD&T: True position ±0.05mm all holes
- Availability: Low-Mid Volume / Made to Order
5. Medical Device Housing — Mirror Finish
Model ID: MHT-MED-HSG-MCH
Industry: Medical Devices
Description: Hot chamber zinc die cast medical instrument housing with CNC-machined sealing grooves, connector cutouts, and precision assembly register features. Mirror-finish machining on external visible faces prepares the surface for Class A electroplating with zero tool mark read-through after plating.
Technical Specifications:
- Material: Zamak 5 Hot Chamber
- Surface Finish: Ra 0.4 µm on plating faces
- Features: Sealing grooves + connector cutouts
- Finish: Pre-plating mirror machined
- Availability: Prototype & Production
