Optimising Inconel Tooling with 5-Axis CNC Milling and EDM Spark Erosion
The Challenge
A UK engineering client required a specialist tooling component manufactured from Inconel 625, incorporating deep pockets, compound-angle surfaces, narrow internal features and several close-tolerance locating faces. The component formed part of a reusable production fixture, making dimensional stability and surface condition critical to reliable assembly.
The main difficulty was machining the combination of tough material and restricted feature access without introducing excessive tool deflection or vibration. A conventional three-axis approach would have required multiple setups, increasing datum-transfer risk and extending machine time. One internal blind feature also required geometry that could not be produced efficiently with conventional cutting tools.
The client required a dependable subcontract manufacturing UK route capable of handling the complete component without sending the part between multiple suppliers.
The Engineered Solution
The engineering team at Strategic Innovations Dundee Ltd began by reviewing the component geometry and identifying the features that would benefit most from simultaneous-axis machining. The manufacturing strategy centred on 5-axis CNC milling, allowing the workpiece to remain securely located while the cutting tool approached compound surfaces from controlled orientations.
For the Inconel 625 billet, machining parameters were selected to manage heat generation and cutting-force variation. Roughing operations were programmed with controlled radial engagement rather than aggressive full-width cuts, reducing thermal loading and helping protect cutting edges. Adaptive tool paths were then used to clear the deeper pockets progressively before semi-finishing.
The 5-axis approach reduced the requirement for repeated repositioning and allowed several angular faces to be machined from a common datum structure. Particular attention was given to thin sections where excessive tool stick-out could have generated deflection. Shorter tooling assemblies and controlled step-downs helped maintain stability during finishing.
The most challenging blind internal feature was subsequently produced using EDM spark erosion. Rather than forcing a small milling cutter into a restricted area, the engineering team developed an electrode-based process that provided controlled material removal while preserving the required geometry. This approach was particularly valuable for the hardened or difficult-to-machine sections where conventional cutting would have increased tool wear and cycle time.
Following machining and EDM operations, critical locating surfaces were carefully finished to achieve a representative Ra 1.6 µm surface requirement. Edge-breaking and deburring were completed without compromising the functional faces, while final inspection focused on datum relationships, pocket geometry and feature alignment.
This integrated approach demonstrated the flexibility expected from precision engineering Dundee, combining advanced milling and specialist EDM capability within one manufacturing route.
Outcome & Operational Impact
In this representative scenario, consolidating the manufacturing process reduced setup requirements from four operations to two, delivering an estimated 50% reduction in setup time. Total manufacturing lead time was reduced from approximately 12 working days to 8, primarily by eliminating external processing between milling and EDM stages.
The finished tooling component achieved the required functional surface condition, including representative Ra 1.6 µm finishes on specified locating areas. Single-source production also simplified scheduling and reduced transportation between subcontractors.
The project demonstrates how CNC machining Scotland can combine 5-axis capability, EDM expertise and practical process engineering to manufacture difficult materials without unnecessarily increasing production complexity.
CTA:
Have a complex engineering component or production bottleneck? Send your technical specifications and RFQ straight to the engineering team at Strategic Innovations Dundee Ltd for a comprehensive manufacturing evaluation.
