forum.cncdrive.com

Hello,

How to define the Helix pitch?

"To interpolate an arc or helix in the center format, program G2 (or G3) X... Y... Z... I... J... K... ,
where X and Y and Z are the endpoint coordinates and
– if the G17 plane is selected then I and J specifies the center of the arc.
– if the G18 plane is selected then I and K specifies the center of the arc.
– if the G19 plane is selected then J and K specifies the center of the arc.
"

Well, there are 3 linear axis in the coordinate system, XYZ and the 3rd axis which is not on the arc plane is which defines the helix height.
For example in G17 the XY plane is selected, then the 3rd axis is the Z, so if you code Z coordinate different then the starting Z coordinate then it will be a helix.

cncdrive wrote:Well, there are 3 linear axis in the coordinate system, XYZ and the 3rd axis which is not on the arc plane is which defines the helix height.
For example in G17 the XY plane is selected, then the 3rd axis is the Z, so if you code Z coordinate different then the starting Z coordinate then it will be a helix.

Yes Z Defines a helix but how to do pitch of helix?


In linuxcnc "P" defines the mumber of helix turns.
https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g2-g3

Pitch is Z depth in 1 revolution.
If you want to make multiple passes, you call multiple G2 or G3 lines, like this.
Pitch is 0.25.

G0 X50.1828 Y23.0854 Z0.1250
G1 X50.1828 Y23.0854 Z0.0000 F10
G2 X50.1828 Y23.0854 Z-0.2500 I0.0000 J-0.2500 F20
G2 X50.1828 Y23.0854 Z-0.5000 I0.0000 J-0.2500
G2 X50.1828 Y23.0854 Z-0.5000 I0.0000 J-0.2500
G0 X50.1828 Y23.0854 Z0.1250