CNC Program Example: G03 Circular Interpolation – Master the Math Behind CNC Machining

Now a day CAD and CAM software make our lives just easier and easier, you just not have to calculate a single point in drawing, every thing is just ready. But it is a good practice to know actually how the calculations are being done, if not all but some which are necessary for a CNC programmer.

CNC Program Example G03 Circular Interpolation

The calculation of G02 G03 circular interpolation values is a good technique to learn. This CNC program tells not all but a little of course enough for the beginner CNC programmer and CNC students.

CNC Program With G03 Circular Interpolation

CNC Program Example G03 Circular Interpolation

N1 G00 X0 Z0
N2 G01 X11
N3 G01 Z-15
N4 G03 X11 Z-27 I-8 K-6

Description

The I and K for the G03.

I Calculation for G03 Circular Interpolation

I is the distance from the arc start point to arc center point in x-axis. This value is not given in diameter but as a radius value, so

• Find the start diameter it is 11
• Now make it radius value by dividing it by 2 such as 11 / 2 = 5.5
• This is a easy example in way that the arc center point distance from the workpiece center point is given other wise we have to calculate it.
• So now just add 2.5 in 5.5 earlier calculated 2.5 + 5.5 = 8
• This is the value of I 8 this is the distance from the arc start point to the ace center point.

K Calculation for G03 Circular Interpolation

K is the distance from the arc start point to arc center point in z-axis.

• In this example it is just easy as you just have to subtract 21 from 15 such as 21 – 15 = 6.
• So the value from the arc start point to the arc center point in z-axis is 6