NTK Cutting Tools Highlights Benefits of High-Speed Ceramic Machining

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NTK Cutting Tools Highlights Benefits of High-Speed Ceramic Machining

NTK Cutting Tools Highlights Benefits of High-Speed Ceramic Machining

Industry News
Oct 12,26

NTK Cutting Tools, a member of the IMC Group, highlights how higher cutting speeds and stable machining conditions can improve ceramic tooling performance and productivity.

NTK Cutting Tools Highlights Benefits of High-Speed Ceramic Machining

Ceramic cutting tools require a different approach to conventional carbide machining, with higher cutting speeds generating thermal conditions that can improve tool life, material removal rates and productivity.

Reducing speed is often appropriate in carbide machining when cutting edges wear quickly, processes become unstable or inserts show signs of failure. Applying the same response to ceramic tooling, however, can undermine performance.

An illustrative first trial involves an application engineer recommending an increase in cutting speed from 250 m/min to 900 m/min for a ceramic roughing operation. An operator accustomed to carbide machining questions the nearly fourfold increase and starts at 400 m/min instead. The resulting poor tool life, unexpected wear and disappointing productivity can lead users to conclude that ceramics are unsuitable for their operations, although the insert has not operated under its intended conditions.

The difference lies in how heat affects the workpiece and cutting tool. In conventional carbide machining, higher temperatures usually accelerate wear, shorten tool life and reduce process stability. High-speed ceramic machining of heat-resistant superalloys and cast irons can exhibit a different relationship between heat and performance.

Nickel-based alloys retain extremely high strength at room temperature but soften as temperatures rise. Around 800°C, their resistance to deformation decreases significantly, making them easier to cut. Ceramic cutting materials retain hardness and wear resistance at temperatures that would rapidly degrade conventional carbide grades.

These conditions allow the workpiece to become easier to machine while the ceramic cutting edge retains its strength, resulting in lower cutting forces, higher material removal rates and greater productivity. High recommended speeds therefore serve to establish suitable thermal conditions as well as accelerate material removal.

Reducing the recommended speed during initial trials may prevent the cutting zone from reaching the temperature needed for thermal softening. The material remains difficult to machine, cutting forces increase and productivity suffers.

In one rough milling application on Inconel 718, increasing cutting speed from approximately 400 m/min to over 1,000 m/min significantly reduced machining time and produced lower wear than the slower cutting conditions.

Process stability remains essential. Stable workholding, secure toolholding, minimal overhang and a vibration-free setup contribute to successful ceramic machining. Smooth tool paths and reduced interruptions help minimise impact loads during milling, while stable engagement and consistent cutting conditions support performance in turning.

Ceramic milling is typically performed dry, as the high temperatures generated during cutting are part of the process. Intermittent coolant application can cause thermal shock and damage the cutting edge. In turning, coolant can often be applied successfully because continuous cutting-edge engagement avoids the repeated heating and cooling cycles common in milling.

Unlike carbide machining, reducing cutting speed is rarely the first parameter adjustment required when problems arise with ceramics. Improving process stability is more often the solution.

Adoption also requires operators to reconsider habits developed through carbide machining. Ceramic inserts constitute a different cutting technology, with distinct operating principles and a different performance window.

With decades of ceramic development experience, NTK Cutting Tools offers a comprehensive portfolio for heat-resistant superalloys and cast iron machining. The range includes SiAlON grades for high-speed HRSA roughing and ceramic solutions optimised for grey and ductile cast irons, helping manufacturers achieve productivity levels that conventional carbide tooling often cannot reach.

High recommended cutting speeds reflect both the insert’s ability to withstand demanding conditions and the thermal requirements needed for the technology to perform as intended.

NTK Cutting Tools, a member of the IMC Group, is a global supplier of advanced cutting tool solutions for the metalworking industry. The company specialises in ceramic tooling for high-temperature machining, alongside miniature and Swiss-type machining applications where precision and process stability are critical. Its broad tooling portfolio helps manufacturers increase productivity, maintain process stability and improve resource efficiency across aerospace, automotive, medical, electronics and general engineering industries.