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Can't get 4th Axis to Work
« on: March 07, 2015, 10:18:34 PM »
Hello All,
I've recently added a 4th axis (rotary table with stepper motor) to my mill and cannot get it to work right for the life of me. I've searched and read every thread that had to do with 4th axis setups and despite all the good info and screen shots, am coming up empty handed. It's an X3 mill using Gecko G540. Axis of rotation is parallel to X.

Problems are:
1. Steps per inches or degrees. I can manually type G0 A90 etc and the rotab will rotate 90 degrees, and can always go back to zero.
When I run a file (CNC Wrapper, Cambam Wrapper Plugin, or GCode Ripper) I get a mess of lines all stacked up on top of each other. The axis suddenly seems to switch to linear, the Gcode will call for A18 and the axis will spin round and round (1.898" diameter PVC pipe) until it gets there. The original DXF was drawn to the size based on what the calculator in CNC Wrapper told me I needed for a 30 degree wrap.

2. After running a failed file, when I hit Go To Zero, the other axes are ok but the rotab only moves a few degrees and stops somewhere which was not the original zero point I started with.

I used 200x10x72 / 360=400 which got the steps right for manual gcode entry and also tried 200x10x72 / 3.142 which I've also seen posted here as a suggestion, which is correct?

3. I can't remember if I fixed this or not, but at one point, the rotation was only going in one direction despite the Gcode for A going low to high to low again.


Settings:
Config Screen
all 3 Rotational boxes are unchecked
A is Angular is checked

Toolpath Configuration
X-axis
A-Rotations enabled
User Radius for feedrate
all checked

Settings Tab F6
I tried the diameter and radius in the Rotation Diameter DRO with no luck

Ports and Pins
Also tried checking the Emulated box for Input Signals for the Z-- row

Any help is greatly appreciated!
« Last Edit: March 07, 2015, 10:24:46 PM by REZCAR »

Offline ger21

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Re: Can't get 4th Axis to Work
« Reply #1 on: March 07, 2015, 10:25:22 PM »
Quote
Settings:
Config Screen
all 3 Rotational boxes are unchecked

"A-Axis is angular" should be checked.

Quote
Settings Tab F6
I tried the diameter and radius in the Rotation Diameter DRO with no luck

If Z zero is the center of your axis, enter 0.
If Z zero is the surface of your part, enter the radius.
I think this really only affects the feedrate.
Gerry

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http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html
Re: Can't get 4th Axis to Work
« Reply #2 on: March 08, 2015, 01:46:59 PM »
Thanks Gerry,
I added the A-axis is angular while you were replying to me. I've also done the radius, diameter and zero too. There must be something else in my setup that's overriding all the rotation settings.