Machine tools might not be the first thing that springs to mind when somebody talks about "whirling". In fact, you could be forgiven for drifting off into daydreams about rides at the funfair and mystic Sufi practices. However, in this case, we are talking about a machining process, or more specifically a profile milling process that employs special tools and kinematics. The process is primarily used as a cost-effective means for preparing rotationally symmetrical precision and shaped workpieces ahead of grinding. A special whirling machine or a leadscrew lathe fitted with a whirling attachment are usually used. One of the leading lights in whirling is Burgsmüller GmbH, which is based in Einbeck, Germany, and in fact helped invent the technology, making it a pretty well-established expert in the field.
To show what it can do, Burgsmüller is exhibiting the new WM 250 - 8000 at EMO Hannover 2017, a whirling machine with an impressive machining length of 6,250 millimeters. The biggest strength of the machine lies in its outstanding precision for hard-whirling ballscrew spindles. The flank diameter tolerance along the full machining length is just plus/minus seven micrometers. This precision is achieved thanks to a prism guide bezel that grips and centers the free end of the bar material while also freeing up the spindle axis so that the bar material can be pushed through. Subsequent machining of the pre-whirled thread during the setting-back procedure is also monitored with measurement technology.