Machining tests at tool-holder manufacturer Gewefa’s factory in Burladingen, Germany, have demonstrated the benefits of combining a Wunschmann trochoidal milling cutter with an SK40 Plan hydraulic expansion chuck. The set up improved cutting performance when machining difficult-to-cut nitriding steel, reducing noise while maintaining dimensional accuracy and surface quality. The sole sales agent for Gewefa products in the UK and Ireland, Nydaloxe Precision, describes the machining tests, which produced optimal results in terms of tool life, dimensional accuracy and surface quality. 

The application involved milling a 1160 mm long slot, 20 mm wide and 6.5 mm deep, into 34CrAlNi7 nitriding steel, valued for its surface hardness and wear resistance. 

“With our solid-carbide 175 ER trochoidal mill, which has a corner radius, we have the ideal cutting tool for slotting in such a demanding material,” says managing director Stephan Wunschmann. 

The cutter was initially tested in a collet chuck with face-and-taper contact on Gewefa’s AXA five-axis machining centre. Although the resulting accuracy and surface finish were satisfactory, noise levels were high. Replacing the collet with a Gewefa SK40 hydraulic expansion chuck resolved the issue. 

The hydraulic chuck provides uniform clamping pressure around the tool shank, delivering a concentric, play-free connection and typically less than 3 µm runout. Its rigidity reduces vibration, while the dual-contact interface helps prevent axial movement under heavy radial loads. 

The 175 ER solid carbide-cutter features five polished chip flutes, a robust core and a high-performance PVD coating designed to withstand the temperatures and oxidation associated with hard machining. 

Hydraulic expansion technology also offers practical benefits, reducing set-up time by an average of 75% compared with shrink-fit chucks and eliminating the need for heat-shrink equipment. 

More information www.nydaloxeprecision.com