Coordinate System

To program a toolpath in a CNC application, the profile must be described to define the toolpath. This is done by defining points relative to the zero point of the coordinate system.

A coordinate system consists of 2 axes, which are perpendicular to each other and have a common zero point. Their positive directions are shown by the arrows. The horizontal line is usually called the X-axis or abscissa axis, and the vertical line is usually called the Y -axis or ordinate axis. The intersection point is called the zero point and is designated with a quadrant zero. When turning, the horizontal axis is designated with Z and the vertical axis is designated with X. This is called a Cartesian coordinate system.

When turning, the Z axis is always parallel to the main spindle.

Normal coordinate system (Milling)

Normal coordinate system (Turning)

If you add an extra axis to the two, you have a 3D coordinate system used when milling.

The Four Quadrant Coordinate Values

Quadrant 1: X values + and Y values +
Quadrant 2: X values - and Y values +
Quadrant 3: X values - and Y values -
Quadrant 4: X values + and Y values -

Assignment: Find X and Y coordinates

Look at the drawing above and find the X and Y coordinates for the following positions.