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M38 Spindle speed variation on
Haas NGC M-code · Lathe
Turns on spindle speed variation to break up chatter. The speed swings by Setting 165 RPM over the Setting 166 cycle time.
Format
M38
How it works
Modal until M39.
Example program
G97 S1000 M03 (1000 RPM)
M38 (SPEED VARIATION ON)
G01 Z-3. F.008 (LONG TURN THAT CHATTERS)
M39 (SPEED VARIATION OFF)
M38 (SPEED VARIATION ON)
G01 Z-3. F.008 (LONG TURN THAT CHATTERS)
M39 (SPEED VARIATION OFF)
Example is in inch. Check offsets and clearances first.
Watch out for
- Start small, about 100 RPM over 1 second, and adjust.
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