Wire tools
21 teeth in a 4.35 mm hole: sinker EDM for tungsten carbide machining
Deep cavities, tight radii, hard-to-reach internal profiles, and hardened materials: some machining challenges push conventional milling and grinding to their limits. This is where QP Mechanics turns to sinker electrical discharge machining (EDM) to produce complex features in hardened steel and tungsten carbide, two materials widely used in stamping and extrusion tooling.
Machining hardened steel and tungsten carbide without cutting forces
Unlike conventional machining methods, sinker EDM removes material without direct contact between the tool and the workpiece. Instead of relying on mechanical cutting, the process uses electrical discharges to remove material, making electrical conductivity, rather than hardness, the key factor in machinability.
This allows QP Mechanics to produce complex geometries in hardened steel and tungsten carbide without the high mechanical stresses and tool wear typical of conventional cutting processes. Components can also be machined after heat treatment, in their final metallurgical condition, minimizing the risk of subsequent distortion affecting dimensional accuracy.
The absence of cutting forces is particularly beneficial for thin sections, deep cavities, and delicate features. With properly designed electrodes, accurate wear compensation, and carefully controlled machining parameters, the process can deliver excellent repeatability, even for complex parts, once the machining cycle has been optimized.
A practical application: a tungsten carbide die with internal knurling
One such example of this technology involved producing a tungsten carbide die with a internal knurling machined into a bore just 4.35 mm in diameter.
The profile features 21 teeth, each approximately 0.34 mm high, with a dimensional tolerance of ± 0.01 mm. The combination of such small dimensions, complex internal geometry, multiple teeth, and extremely hard material makes this a particularly demanding task for conventional cutting tools.
Sinker EDM offers a different approach. By reproducing the electrode's shape directly inside the die, the process creates the required profile without exerting mechanical forces on the workpiece. This enables QP Mechanics to produce challenging shapes while maintaining the tight dimensional tolerances required for precision industrial components and tooling.
Working with complex internal geometries or exceptionally hard materials? Visit QP Mechanics' online booth to discover its products and latest developments, and connect with the team to discuss the best solution for your application.
