User's Manual

PMAC User Manual
186 Writing Programs for PMAC
Outside Corner Introduction
If the lead-in move and the first fully compensated move form an outside corner, the lead-in move moves
first to a point one cutter radius away from the intersection of the lead-in move and the first fully
compensated move, with the line from the programmed point to this compensated endpoint being
perpendicular to the path of the lead-in move at the intersection. When the lead-in move is a LINEAR-
mode move, this compensated tool path will be at a diagonal to the programmed move path.
When the lead-in move is a CIRCLE-mode move, this compensated tool path will be a spiral. Then a
circular arc move with radius equal to the cutter radius is added, ending at a point one cutter radius away
from the intersection of the lead-in move and the first fully compensated move, with the line from the
programmed point to this compensated endpoint being perpendicular to the path of the first fully
compensated move at the intersection.
Line
Line
Programmed
Path
Tool Center
Path
Line
Line
Line
Line
Programmed
Path
Tool Center
Path
Arc
Arc
Line to Line Line to Arc
Arc to Arc
Arc to Line
Line
Line
Programmed
Path
Tool Center
Path
Arc
Spiral
Arc
Arc
Spiral
Arc
Introducing Compensation – Outside Corner
Programmed
Path
Tool Center
Path
Arc
Arc
r
r
r
r
r
r
r
r
CC2
CC2 CC2
Arc
CC2
Figure 39 Compensation Outside Corner
The behavior for lead-in moves is different from changing the compensation radius from zero to a non-
zero value while compensation is active. An arc move is always added at the corner, regardless of the
setting of I89. This ensures that the lead-in move never cuts into the first fully compensated move.
Treatment of Compensated inside Corners
Inside corners are still subject to the blending due to the TA and TS times in force (default values set by
coordinate system I-variables Ix87 and Ix88, respectively). The longer the acceleration time, the larger
the rounding of the corner. (The corner rounding starts and ends a distance F*TA/2 from the
compensated, but unblended corner.) The greater the portion of the blending is S-curve, the squarer the
corner will be.
When coming to a full stop (e.g., Step, Quit, or DWELL at the corner) at an inside corner, PMAC will stop
at the compensated, but unblended, corner point.