HEIDENHAIN TNC 640 User Manual page 649

Turning | Turning program functions (option 50)
Programming undercutting
Undercutting is usually required for the flush connection of
counterparts. In addition undercutting can help to reduce the
notch effect at corners. Threads and fits are often machined with
an undercut. You have various contour elements for defining the
different undercuts:
UDC TYPE_E: Undercut for cylindrical surface to be further
processed in compliance with DIN 509
UDC TYPE_F: Undercut for plan and cylindrical surface for
further processing in compliance with DIN 509
UDC TYPE_H: Undercut for more rounded transition in
compliance with DIN 509
UDC TYPE_K: Undercut in face and cylindrical surface
UDC TYPE_U: Undercut in cylindrical surface
UDC THREAD: Thread undercut in compliance with DIN 76
The control always interprets undercuts as form
elements in the longitudinal direction. No undercuts are
possible in the plane direction.
HEIDENHAIN | TNC 640 | ISO Programming User's Manual | 10/2017
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