Programming counter-spindles in G-code
Standard lathes have a spindle into which the workpiece is chucked and then machined with turning or milling tools. To allow the workpiece to be completely machined (including the “back” side) it must be rechucked by hand – a process in which errors can often be made at the expense of the precision of the workpiece. By using machines with counter-spindles, this process is automated, allowing a much higher level of precision to be achieved. These counter-spindles pick off the workpiece from the main spindle with positional accuracy so that it can be completely machined on one machine. The operator can simply program takeover of the workpiece with ShopTurn in one cycle. If ShopTurn is not available, synchronization must be programmed via G-code.
The following example describes this sequence. Siemens accepts no liability for the general validity and functional safety of the program example shown.
Synchronous takeover at 1000 rpm
Pull-back position counter-spindle absolute
With the mirror command, the control system automatically resets the path correction commands (G41/G42 and/or G42/G41) in keeping with the change in machining direction – that is, G42 external machining is also programmed on the counter-spindle.