Feed Rate Mode G Codes (G93, G94, and G95)

CNCCookbook’s G-Code Tutorial

G93 G Code:  Inverse Time

Inverse time mode is used to program simultaneous coordinated linear and rotary motion.  It basically causes F (the feedrate command) to cause a move to be completed in 1/F minutes.  So, if F is 2.0, the move should be completed in 30 seconds.

When inverse time mode is active, an F word must be present on every line that has a G01, G02, or G03.  G93 does not affect G00 motion.

G94 G Code:  Feedrate Units Per Minute

In the Units per Minute mode, the F word causes motion in units per minute.  When the gcode is set to Imperial mode, the units will be inches per minute.

G94 is what most will regard as the "normal" feed rate mode.

G95 G Code:  Feedrate Units Per Revolution

G95 is convenient for programming chip loads on lathes.  It causes the motion to be in units per spindle revolution.

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