A new method for the production of blisks, developed by Delcam and the 600 Centre, was shown for the first time at the Productivity Partnerships event held at the 600 Centre during November.

The profile of the blades was machined in the conventional way, using the range of five-axis strategies available within Delcam's PowerMILL CAM system on a Fanuc Robodrill T21iE fitted with a 24,000 rpm spindle and a Nikken 130 unit to provide fourth and five axis movements. However, the cooling holes, which are arranged at compound angles to the blade surface, were then added with a series of helical toolpaths, also programmed with PowerMILL, using a 1.5mm endmill in 0.5mm steps.

This approach allows the profile shape and the holes to be machined in a single operation. It saves time by eliminating the need for a lengthy, separate EDM process to generate the holes, with the added potential problem of maintaining accuracy as the electrode wears. The novel process is also more effective than drilling the holes since the helical toolpath minimises the chance of tool breakage and leaves the surface around the holes free of burrs.