Iruba Innovations out of Kronach, Germany has developed a unique solution to a difficult milling problem. Creating 'fir-tree' gear profiles and turbine blade-roots is remarkably difficult, requiring multiple toolsets to create a particular shape. But then you see a picture like this.....
....and wonder how they did it. First check this video of the Iruba tool running on a Hermle C60 (after the jump)
According to a release by Delcam, an Iruba partner, there are some significant advantages to their Trochoidal milling technique.
The use of PowerMILL’s trochoidal strategies gives a number of benefits, in particular giving high material removal rates with lower, and more consistent, cutting forces. The more consistent cutting forces also ensure higher accuracy in the position and in the shape of the slots, with minimal thermal effects on the surface of the profiles. The process also reduces the number of specialist cutting tools that are required, and cuts the machining time in steel alloys by between 30 and 40 per cent, compared to alternative standard milling solutions, giving a time almost equal to broaching.
Milling, deburring and measure of straight and curved slots was done with one process, using Hermle's smallest 5-axis, the C22. How does this work?
Trochoidal milling is a relatively new technique that relies on rotating the tool in a circular fashion, cutting the workpiece intermittantly rather than constantly as CNC machines usually do. The advantage is that a small tool can remove a larger area on the workpiece whilst the lower required cutting force preserves the lifespan of the tooling and enhances accuracy. While Trochoidal milling isn't as quick as traditional methods, single-pass milling is certainly appealing as a way of decreasing downtime.
For a little more explaination, check out this great video by Sandvik Coromant.