The MillTurn series of machines manufactured in Austria by WFL are used around the world to produce complex parts to high tolerances.

These components include compressor rotors, for which the company has developed a highly productive method for automated complete machining. A key component of this solution is the TC63-Digilog probe from Blum-Novotest, which is used to scan workpiece contours in a matter of seconds without the need to unclamp the workpiece from the machine.
The compressor rotor is made of GG60 grey cast iron, measuring around 400 mm long with an outer diameter of roughly 160 mm. By using special forming cutters, the rotor is turned and milled on an M40 MillTurn machine down to gauge-block standard in grinding quality. The machine does this automatically in a 24/7 operation, resulting in significantly shorter machining times.
Until now, grinding was required during the rotor manufacturing process because the necessary accuracy and surface quality could not be achieved by milling.
“Although the new process does not allow us to dispense with grinding in all applications, it is however sufficient that our procedure substantially reduces the amount grinding necessary,” explains WFL product manager Manfred Baumgartner.
During the finishing process, the workpiece is initially prefabricated to an excess of two-tenths of a millimetre. This contour is measured on the machine using the digital and analogue TC63-Digilog touch probe. Engineers can scan the entire circumference of the milled profile without unclamping the workpiece from the machine. In this way, the component’s geometrical accuracy and concentricity is determined “in double-quick time”.
From the resulting contour – which is shown on the CNC display – an algorithm calculates the optimum corrections for every tool engagement.
For further information www.blum-novotest.com