Path Control

Between two blocks the control has a choice: come to a stop and turn the corner exactly, or carry speed through it and cut a corner that is slightly rounded. Which it does is programmed, and it is the difference between a finish pass that takes twenty minutes and one that takes an hour.

The modes

Code	What happens at a corner
G61	the axes stop, the corner is cut exactly, then the next block starts
G64	speed is carried through, cornering limited by what the axes can stand. This is the default
G64.1 P_	speed is carried through and the corner is deliberately rounded to the tolerance P allows

G64 and G64.1 are not two settings of one thing. G64 never departs from the programmed path: the corner is sharp and the machine slows for it. G64.1 allows a rounded corner and rounds it no more than P, which is what buys the speed.

A P word on bare G64 is ignored. If you want a tolerance honoured, ask for G64.1.

Leaving P off G64.1 uses a small built-in tolerance rather than refusing the block, so state P when the number matters.

The machining condition level

G05.1 Q1 R_ selects a machining condition level from 1 to 10. One word moves both the tolerance the path is compressed to and the dynamics the axes are allowed, from speed-priority at one end to precision-priority at the other.

What each level means is the machine’s own scale, set at commissioning. A machine whose scales are left at 100% accepts the level and changes nothing. That is the safe default, not a fault.

G05 P10000 turns on high-precision contour mode

G05 P10000 turns it on and G05 P0 turns it off. Those are the only two forms: a G05 P10001 L1 block, which on some controls calls a stored high-speed cycle, is refused rather than quietly ignored.

Entry is refused while any of these is active:

• cutter compensation
• a canned cycle
• scaling or mirroring
• polar or cylindrical interpolation
• constant surface speed

Cutter compensation also blocks the exit. A program that turns comp on inside the mode cannot leave it, so cancel comp before G05 P0. The same rule applies at both ends.

This mode and the machining condition level are licensed options; without them the block is refused before the program runs.

What none of this changes

• It is not a feed override. These modes decide how corners are taken, not how fast the programmed feed is. The dial is on the panel; see Overrides & Run Options.
• A tolerance is not the machine’s accuracy. G64.1 P0.01 allows a corner to be rounded by that much; it says nothing about whether the machine can hold it. Geometry is Volumetric Compensation.
• The limits still bind. Whatever the mode allows, the axes are held to the dynamics set on the machine; see Axes & Channels, whose Path Control group is where these tolerances and the level scales are declared.

Where to go next

• Axes & Channels: the machine-side settings these codes select between.
• Canned Cycles: one of the states that refuses entry to high-precision mode.