4th axis on non simultaneous controller

[lukaszossowski]

Hi,

I have a 4th axis machine with a controller that does not support simultaneous movement in all 4 axes. I can go either XYZ or AYZ. 

I created a simple part in designer with a square pocket with rounded corners wrapped around a cylinder. A very simple geometry, all walls perpendicular. I created a 2D pocket operation.

I'm using a slightly modified FANUC postprocessor (not 100% sure of that) which works great in XYZ and I further modified it with aAxis enabled  and configured in onOpen function.

However the resulting code, while valid for the machine (it does open and display properly in preview), has movement in all 4 axes, meaning it can't be run properly on my machine.

Is the generated simultaneous code a result of the postprocessor or the path generated by Fusion? Even on simulation in fusion it looks like it should not move the X axis (which is perpendicular to the A axis), but in the resulting gcode it does.

Any help with getting that resolved would be greatly appreciated. I could draw the same pocket on a flat surface, scale it properl and then simply swap X and A in the resulted g-code, which I assume would give me a correct toolpath, but perhaps there is a better way?

Attached is the pocket I would like to machine.

Thanks.

[boopathi.sivakumar]

Hi @lukaszossowski

Did you try with fanuc with A axis post

https://cam.autodesk.com/hsmposts?p=fanuc_with_a-axis 

it has already pre-configured for 4th axis with inverse time feedrate capabilities as well. you can check this out

[lukaszossowski]

Thank you, this does seem to generate correct code when it comes to G1, however the inverse time funcionality is not supported by my machine. Is there an easy way to disable it? 

[boopathi.sivakumar · Accepted solution]

@lukaszossowski 

Yes it is easy to make changes to disable the inverse time feedrate

Edit the post and find for this line and make it false

var useInverseTimeFeed = true; // use 1/T feeds

 also you need to find this line

} else if (true) { // combination FPM/DPM

 Change this to false as well

That's all!! you should now able to get the expected output

[lukaszossowski]

Thank you very much, it does work now!