What is Helical Milling | How to Program Helical Interpolation | CNCLATHING


Helical interpolation can only be performed on CNC machines because it requires simultaneous motion in multiple axes, typically on milling machines. How to make a helical interpolation program is what people concerned. Here we’ll present an example of the process and explain what is helical milling.

What is Helical Milling?

Helical milling is a hole-making machining process in which the cutter proceeds a helical path while rotating around its own axis, used to produce helical parts like helical gears, spiral flute milling cutters, twist drills, and helical cam grooves. Milling helical parts need to use special formed milling cutters and double-angle milling cutters. A 3-axis CNC milling machine is suitable for performing the helical interpolation operation. 


Helical interpolation is a milling technique that can replace drilling or even better when creating holes. A helix is a regular curved path, the helical path can be decomposed into axial and tangential directions, combining frontal and peripheral cutting. Helical interpolation involves simultaneous circular movement in the X and Y axes combined with an axial feed on the z-axis at a defined pitch. 

What Can Helical Interpolation be Used for?

Helical interpolation is a fast, economical and versatile operation, which is programmed by adding a z-axis movement to a simple circular interpolation command using CAM software. 

– Generating holes: helical milling is an easy way to open an existing hole or make a flat bottom hole rather than using the drill. There are some drawbacks of using a twist drill, for example, it requires additional tool change and maybe another slot, in addition, twist drills burn up more horsepower than the equivalent helical interpolation. But end mills will be much slower than a twist drill with the correct size. 

– Circular ramping: to cut down to depth before machining a feature such as a pocket or a slot, or even use it to start off cutting the profile to bring the cutter down to depth.

– Thread milling: cut a thread by milling down in a spiral using a mill, this is great for producing threads in a hard material such as titanium.

How to Program Helical Interpolation - Helical Interpolation Program Example

How to do helical interpolation on a CNC mill? Programming helical interpolation is unique, because the procedure is programmed via arcs. Here is the helical interpolation program example. The helix is a series of G03 arc commands, the shape will be created when the arc curls and descends, during the operation, X, Y, and Z axes are moving simultaneously. 

N6 T0606 (40MM End mill);


G90 G54 G21 G17 G80 G43;

S1000 M03;

G00 X0.0 Y0.0

Z1.0 M08;

G01 Z0.1 F200.0;

G03 X60.0 Y0.0 Z-2.0 R30.0;

G03 X0.0 Y0.0 Z-4.0 R 30.0;

G03 X60.0 Y0.0 Z-6.0 R30.0;

G03 X0.0 Y0.0 Z-8.0 R30.0;

G03 X60.0 Y0.0 Z-10.0 R30.0;

G03 X0.0 Y0.0 R30.0;

G03 X60.0 Y0.0 R30.0;

G00 X30.0 Z1.0;

Z50.0 M09;

G53 X0.0 Y0.0 Z0.0 M05;