CNC Machining

Precision machining for cast and fabricated components

CNC machining is available as a standalone service and as a post-casting operation fully integrated into our investment casting and gravity die casting supply chain. Whether you need a casting machined to a finished drawing, a batch of bar-stock components turned to print, or a mixed programme of cast-and-machine parts shipped on a DDP basis, we manage the full process through our ISO 9001:2015 certified partner machine shops.

All machining is performed on modern CNC equipment — machining centres, turning centres and grinding machines — with in-process and final inspection carried out on coordinate-measuring machines (CMM). First Article Inspection Reports (FAIR) and In-Process Inspection Records (ISIR) are available on request.

Processes

• CNC milling — 3-axis and 4-axis machining of prismatic features, pockets, slots, bolt-hole patterns and complex profiled surfaces
• CNC turning — cylindrical turning, facing, boring, threading (internal and external) and parting on multi-axis turning centres
• Grinding — surface and cylindrical grinding to tight tolerances on sealing faces, bearing journals and close-fit diameters
• Drilling and tapping — precision hole patterns, reamed bores and threaded features to drawing
• Deep-hole drilling — axial bores and cross-drillings in valve bodies, manifolds and hydraulic components

Materials we machine

Our partner shops machine the full range of materials we supply through casting, as well as bar and plate stock where required:

• Stainless steel — austenitic (304, 316, 316L), duplex (2205), super duplex, martensitic and precipitation-hardening grades
• Aluminium alloys — LM25, LM6, LM9, 6061, 7075 and other wrought and cast alloys
• Carbon and alloy steels — including case-hardening and through-hardening grades
• Copper alloys — brass, bronze and gunmetal
• Engineering plastics — PEEK, Delrin, nylon and PTFE for specialist applications

Tolerances and surface finish

General machined tolerance	ISO 2768-m as standard
Close-tolerance features	ISO 2768-f or to drawing (H7/h6 fits routinely achieved)
Threaded features	Metric and imperial; 6H/6g tolerance class standard
Surface finish (turned)	Ra 1.6 µm standard; Ra 0.8 µm on request
Surface finish (ground)	Ra 0.4 µm achievable on sealing and bearing faces
Inspection	CMM dimensional report; FAIR/ISIR on request

Integrated casting and machining

The most efficient way to source complex components is to combine casting and machining under one supply chain. When we manage both operations, we can:

• Design casting datums and machining allowances from the outset, reducing stock removal and cycle time
• Hold all quality records under one ISO 9001:2015 system with a single certificate package
• Deliver a fully finished, dimensionally verified component rather than a casting that requires further work on your site
• Reduce lead time by eliminating the hand-off between a separate casting supplier and machine shop

This is particularly valuable for pressure-bearing components where both the casting and the machined features must meet tight tolerances and the full assembly needs to be pressure-tested before shipment.

Quality and certification

• ISO 9001:2015 quality management system throughout the supply chain
• CMM dimensional inspection with full reports available
• First Article Inspection Report (FAIR) to AS9102 or equivalent on request
• Material traceability maintained from raw material through to finished part
• Surface finish measurement by profilometer
• Thread gauging to specified tolerance class

Industries and applications

• Valves and flow control — seat bores, stem bores, body faces and port drillings machined to drawing
• Pumps — impeller bores, shaft fits, wear ring clearances and seal housing features
• Oil and gas — close-tolerance components for wellhead, downhole and process equipment
• Marine — corrosion-resistant stainless and aluminium components machined for fit and function
• Industrial machinery — OEM components machined from casting or bar to finished drawing
• Cryogenic — low-temperature valve and instrument components machined to tight seal-face tolerances