Inverse time feed

Q: What does Mazak G-code G93 do?

G93 — Inverse time feed on the MAZATROL SmoothX control (INTEGREX e-670H). When tool radius compensation is performed for a smooth linear or circular small-line-segment command, differences will occur between the shape defined in the program and that existing after tool radius compensation. The feed commands with G94 and G95 only apply for the tool path existing after compensation, and the tool speed at the point of cutting (that is, along the programmed contour), therefore, will not be kept constant so that the resulting speed fluctuations will cause seams on the surface machined. Setting of an Inverse Time Feed command code makes constant the processing time for the corresponding block of the machining program, and thus provides control to ensure a constant rate of feed at the point of cutting (along the programmed contour). Setting of command code G93 specifies the inverse time assign

Q: What is the programming format of G93?

G94 G04 X_; or G94 G04 P_; Data must be set in 0.001 seconds. For address P, the decimal point is not available. Setting a decimal point will cause an alarm.

Machine-specific. This G-code reference is specific to the Mazak INTEGREX e-670H / e-670H-S with the MAZATROL SmoothX control (EIA/ISO programming manual H747PB0030E). G-code availability depends on fitted options, and groups and behaviour differ between Mazak models and control generations — verify against the manual for your own machine before programming with any code.

What it does

When tool radius compensation is performed for a smooth linear or circular small-line-segment command, differences will occur between the shape defined in the program and that existing after tool radius compensation. The feed commands with G94 and G95 only apply for the tool path existing after compensation, and the tool speed at the point of cutting (that is, along the programmed contour), therefore, will not be kept constant so that the resulting speed fluctuations will cause seams on the surface machined. Setting of an Inverse Time Feed command code makes constant the processing time for the corresponding block of the machining program, and thus provides control to ensure a constant rate of feed at the point of cutting (along the programmed contour). Setting of command code G93 specifies the inverse time assignment mode. In the G93 mode, the reciprocal of the machining time for the block of cutting feed (G01, G02 or G03) is to be assigned using an F-code. The setting range of data with address F is from 0.0001 […]

G93 is modal (group 05) — it stays in effect until another code of the same group replaces it.

Programming format

G94 G04 X_;
or
G94 G04 P_;
Data must be set in 0.001 seconds.
For address P, the decimal point is not available. Setting a decimal point will cause an alarm.

Source

Mazak PROGRAMMING MANUAL for EIA/ISO PROGRAM, manual H747PB0030E, section 7-14 Inverse Time Feed: G93 (Option), p. 3-11, 7-25, 7-26, 8-1. Reference and explanation only — not a reproduction of the manual.

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