Preparatory functions ( G Functions)

During the programming the programmer can invoke so-called preparatory functions (G-functions). They determine where to and in which mode (quick traverse, circular interpolation, kind of dimensioning, etc.) a tool shall move. Preparatory functions consist of a G-word with geometrical statements (X, Y, Z, A, ...) and/or technological statements (F, S, T).

Some G-functions of some machine control systems are active already after having switched on the CNC machine (start condition) and do not have to be programmed any more (e.g. GO, G17, G40, G90). Other preparatory functions are locking (modal active), i.e. they are active also for following blocks until they are made inactive by other, contra effecting G-functions.

Preparatory function Meaning

G 00 Positioning in quick traverse G 01 Interpolation of straight lines G02 Circular interpolation clockwise G 03 Circular interpolation counter clockwise G 04 Dwell time in seconds G 33 Threading with constant pitch G40 Delete tool radius offset G41 Tool radius offset, on the left of the profile G42 Tool radius offset, on the right of the profile G 53 Neutralization of the additive zero offset G 54 Absolute adjustable zero offset G 90 Absolute dimensional statement G 91 Incremental dimensional statement G 92 Set memory G94 Feed speed in mm/min G95 Feed speed in mm/U G96 Constant cutting speed in m/min G 97 Spindle speed in 1/min

Prepared by Azmie Rahman page9of26