Operation Manual

HEIDENHAIN CNC PILOT 4290 235
4.21 Simple Turning Cycles
Undercut cycle G85
With the function G85, you can machine undercuts according to
DIN 509 E, DIN 509 F and DIN 76 (thread undercut). The CNC
PILOT determines the type of undercut using K.
G85 machines the adjoining cylinder if you position the tool to
diameter X “in front of” the cylinder.
The undercut rounding arcs are executed with the radius 0.6 * I.
Danger of collision!
After each pass, the tool returns on a diagonal path before
it advances for the next pass. If required, program an
additional rapid traverse path to avoid a collision.
Parameters
X Target point (diameter)
Z Target point
I Depth (radius)
 DIN 509 E, F: Finishing oversize (default: 0)
 DIN 76: Undercut depth
K Undercut width and type of undercut
 K No input: DIN 509 E
 K=0: DIN 509 F
 K>0: Undercut width for DIN 76
E Reduced feed for machining the undercut (default: active feed
rate)
Also see the following tables