Overrides & Run Options
A program says what to cut. These say how it runs while you watch it.
Overrides
Section titled “Overrides”
The two outer dials are measurements: the feed the machine is actually making, and the spindle’s actual speed. The three in the middle are yours.
| Dial | Scales |
|---|---|
FEED OVR | cutting moves, anything with an F |
RAPID OVR | rapid positioning only |
SPDL OVR | spindle speed |
Feed and rapid are independent. Winding the feed back to 20% to watch a cut does not slow the rapid between cuts, and pulling the rapid down to walk a new program through the air leaves the cutting feed as programmed.
A program can lock the overrides out with M49 and hand them back with M48. A section
that must run at the speed it was written for, such as a thread, is protected that way.
Proving a program out
Section titled “Proving a program out”These four are how you run a program you do not trust yet. Each is a switch you leave on.
Dry Run
Section titled “Dry Run”Cutting moves run at the fast jog rate instead of the programmed feed, so the whole program walks through at a speed you can follow. Rapids stay rapid.
Dry run is for checking the path, usually with the part out of the machine or the Z offset lifted clear. It changes the speed, not the geometry: the tool still goes exactly where the program sends it.
Machine Lock
Section titled “Machine Lock”The program runs, the position display moves, the machine does not. The axes are held where they stand.
This is the way to run a program through the control without moving anything at all, checking that it interprets, that the tools and offsets it calls exist, and that it ends where you expect.
Block Delete
Section titled “Block Delete”Skips every block that starts with /. A program written with optional passes, such as a spring
pass or an extra probe check, carries them on / lines, and this switch decides whether
they run.
Set it before you start the program.
Optional Stop
Section titled “Optional Stop”Makes M01 behave like M00: the program stops there and waits for cycle start. With it
off, M01 is ignored.
Programmers put M01 where a check makes sense: after a first cut, or before a critical
tool. This switch turns those checks on for a first part and off for production.
Switching them during a run
Section titled “Switching them during a run”Set all four before you start.
- Block Delete is decided as the program is read, so switching it mid-run affects whichever blocks the control has not read yet, which is not a boundary you can see.
- Dry Run takes effect on blocks that have not been planned yet, which is some way ahead of the tool. It does not slow the cut you are watching.
- Machine Lock holds the axes still while the program carries on. Clear it mid-run and the machine is left a long way from where the program has got to.
- Optional Stop is the exception: it is read at each
M01, so turning it on part way through takes effect at the next one.
Where to go next
Section titled “Where to go next”- Single Block is one block per start, the fifth switch.
- Start, Feed Hold & Reset covers the keys these modify.