In this type tool position always start from zero . How to moves X ,Y and Z axis , it measure distance from zero . Means tool position always taken from zero . If work  point anywere but its count from zero position .For denoting absolute co-ordinate system  we used preparatory code  G90 used .We consider following example . In following fig there is three place to perform work . it means tool moves at three places . First we  fixed corner of job and take zero position shown by circle on corner. . Labeling to the work position A ,B and C .Tool goes to perform work on first position A at co-ordinate X10 and Y30 .After tool goes to second position B at co-ordinate X30 and Y20 , its measure from zero work position . After tool goes to third position C  at co-ordinate X20 and Y10 , its measure from zero work position.

POINT         X

A                10          30

B               20          30

C                20          10

In  this type , for take tool positioning use work zero at only once time .First giving the work position from work zero , after that tool position for co-ordinate take from previous position. For denoting incremental co-ordinate system we used preparatory code G91 .  Consider following fig . we have to calculate co-ordinate in incremental co-ordinate system .In following fig there is three place to perform work . it means tool moves at three places . First we  fixed corner of job and take zero position shown by circle on corner. Labeling to the work position A ,B and C .Tool goes to perform work on first position A at co-ordinate X10 and Y 30 . Tool goes second position B and its measure from previous position A, at co-ordinate X 20 and Y -10 . Tool goes third position C  and its measure from previous B , at  co-ordinate X-10 and  Y-10 .
POINT      X           Y

A            10            30

B            20          -10

C            -10          -10

ABSOLUTE CO-ORDINATE SYSTEM G90 II INCRIMENTAL CO-ORDINATE SYSTEM G91 II Reviewed by harshal on February 17, 2018 Rating: 5