G90 Absolute Positioning Exercise Explanation
Concept Explanation
This document explains the concept of Absolute Positioning (G90) in CNC machining using a grid-based
exercise.
In G90 Absolute Positioning, all coordinate values are taken from a single fixed origin point - here labeled as
X0 Y0 (the center of the grid).
Each hole (PT1 to PT8) is located using X and Y coordinates based on its distance from this origin.
Positive X -> right, Negative X -> left
Positive Y -> up, Negative Y -> down
Each square in the grid equals 1 unit.
Coordinate Table (PT1 to PT8)
Point
X
Y
PT1
-6
-6
PT2
0
-6
PT3
6
-6
PT4
-6
0
PT5
6
0
PT6
-6
6
PT7
0
6
PT8
6
6