### G03 – Circular Interpolation (Counter Clockwise)

This command runs a circular motion in a counter clockwise direction. The arc starts at the current position and the center is defined by the I, J, K values as an offset of the current position or R for radius. The X, Y & Z values define the finish point. Masso uses Incremental I, J, K values for Arcs

# Syntax & Parameters

• G03 starts an arc movement beginning at the X,Y,Z coordinate location where the G03 was issued.
• X Value – This is the X coordinate defining the end point
• Y Value – This is the Y coordinate defining the end point
• Z Value - This is the Z coordinate defining the end point
• I Value – are relative coordinates and define the X center coordinate as an offset of the starting point X coordinate. (Valid in G17 & G18 planes)
• J Value – are relative coordinates and define the Y center coordinate as an offset of the starting point Y coordinate. (Valid in G17 & G19 planes)
• K Value – are relative coordinates and define the Z center coordinate as an offset of the starting point Y coordinate. (Valid in G18 & G19 planes)

• R Value - Is used to define the arc radius for arcs up to 90 degrees.

Caution: The use of R Value for arcs greater than 90 degrees do not work as it defines multiple center points. For arcs greater that 90 degrees use IJK values for G03 commands.

# Example program for making an Arc

N10 G00 X20 Y10 Z-1
N20 G03 X50 Y40 I0 J30


• In the above example in the first line moves to position X20 Y10 Z-1
• An arc is made starting at position X20 Y10 and ending at coordinate X50 Y40 with center at position X20 Y40 moving in a counter clockwise direction. The Z height does not change.
• The Arc center is calculated as follows
• Starting position X20 + I0 = Center X coordinate X20
• Starting position Y10 + J30 = Center Y coordinate Y40 # Example program for making an Spiral

N10 G00 X20 Y10 Z0
N20 G03 X50 Y40 Z-3 I0 J30


• By adding a Z height into G03 you can create a spiral arc
• In the above example in the first line moves to position X20 Y10 Z0
• An arc is made starting at position X20 Y10 and ending at coordinate X50 Y40 with center at position X20 Y40 moving in a counter clockwise direction. The arc is the same as in the diagram above but the Z axis will descend from its current height to -3 units at a uniform rate over the arc to form a spiral path.
• The Arc center is calculated as follows
• Starting position X20 + I0 = Center X coordinate X20
• Starting position Y10 + J30 = Center Y coordinate Y40

INFORMATION: Units are defined as either inches or mm depending on your machines setup or G20 or G21 command in use.