By the interpolation of X-, Y- and C-axis eccentrically rotating pins can be generated by turnmilling in a standard centric 3-jaw chuck. If the pin is wider than the tool diameter the extra length is machined by an additional feed in the Z-axis.
The complete machining of crankshafts together with oil hole drilling, gear hobbing, spline cutting, etc. in MILLTURN centres is an attractive alternative especially for large crankshafts or prototypes.
The machining is done either from a solid blank or from a forging. Due to the possibility of hard maching pre-grinding after hardening can be eliminated. In this application in-process probing offers all its advantages in compensating thermal and mechanical influences on the workpiece.