HEIDENHAIN TNC 640 (34059x-05) Cycle programming - Manual (Page 168)

Fixed Cycles: Pocket Milling / Stud Milling / Slot Milling
5.8 FACE MILLING (Cycle 233, DIN/ISO: G233)
5
168
TNC 640 | User's Manual Cycle Programming | 1/2015
Strategies Q389=0 and Q389 =1
The strategies Q389=0 and Q389=1 differ in the overtravel during
face milling. If Q389=0, the end point lies outside of the surface. If
Q389=1, it lies at the edge of the surface. The TNC calculates the
end point
2 from the side length and the safety clearance to the
side. If the strategy Q389=0 is used, the TNC additionally moves
the tool beyond the level surface by the tool radius.
4 The TNC moves the tool to the end point 2 at the programmed
feed rate for milling.
5 Then the TNC offsets the tool to the starting point in the next
pass at the pre-positioning feed rate. The offset is calculated
from the programmed width, the tool radius, the maximum path
overlap factor and the safety clearance to the side.
6 The tool then returns at the feed rate for milling in the opposite
direction.
7 The process is repeated until the programmed surface has been
completed.
8 The TNC then positions the tool at rapid traverse
FMAX back to
the starting point 1 .
9 If more than one infeed is required, the TNC moves the tool in
the spindle axis to the next plunging depth at the positioning
feed rate.
10 The process is repeated until all infeeds have been machined. In
the last infeed, only the finishing allowance entered is milled at
the finishing feed rate.
11 At the end of the cycle, the tool is retracted at FMAX to the 2nd
set-up clearance.