setSingularity: LinearizationTolerance for turn/mill Post-Processor

[lorNZLYK]

Hello!

I'm new here, I'll make a presentation post in the right place!

I'm looking for a way to mitigate a problem with movements in a turn-mill machine. 

I need a more accurate syncro between the C axis and X axis, and for that I want to output more points when moving in a straight line. 

I can see that there is a multi-axis option in machineConfiguration inside Fusion (Singularities) that let's me define the linearization tolerance, also I can see in the PP Training Guide the command setSingularity. But when added to the PP, even with the parameter hardcoded, there is no change in the output. I guess I'm missing a call to this setting to check what is the value of the parameter?

Does anybody know a better/simpler way to make this work?

Thank you!

Luís R

[serge.quiblier]

Hi @lorNZLYK 

You don't see any change to your code, but it is expected.
This specific tolerance is only used when linearizing the singularity moves.
The singularity move is, for example, switching from B+ to B- when moving across the north pole of a sphere.
Instead of having a large C axis move (180° most of the time), it will be split in several moves to avoid sudden acceleration. And even the approaching moves may be split "inside" the cone definition.

For your specific request, it's hard to tell, because it depends if the toolpath is linearized by Fusion, or the post engine.
If you can share a f3d file showing the behavior we can have a more accurate analysis.

Regards.

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[lorNZLYK]

Thank you for you answer Serge. 

Let me give some more details.

My problem is exactly that, the movement is a 180º rotation in the C axis, resulting in some marks on the part surface.

This happens when doing 2D or 3D milling toolpaths in a pocket:

In an outside contour for example, instead of having a straight surface, it's oval.. 

If for example I use a S&S toolpath, and on the Smoothing I activate the option evenly spaced points it of course gives the result expected. I wanted to replicate this for the following 2D and 3D strategies. 

Can this be a setting added hardcoded in the PP? 

Thank you again,

Best Regards,

Luís R

[viacheslav.shapilov]

Hello, @lorNZLYK 

As I know, there are some limitations around singularity linearization. Does your machine control supports TCP? If not, you should disable it for all rotary axis:

If TCP is "off", postprocessor will try to linearize movements in singularity. Otherwise, it will rely on controller.

[lorNZLYK]

Hello,

Thank you for you reply @viacheslav.shapilov.

The machine doesn't have TCP, it's a simple turn/mill with only X axis. 

I'm currently running a hardcoded machineConfiguration because the PPs for this machines still aren't updated for the new style with the defineMachine logic and so on.

I guess It's a limitation of the software. The  Smoothing Option as " Evenly Spaced Points" should be an option in all the 3D strategies, that would solve this problem for many people I believe!

Thank you,

Best Regards,

Luís R

[viacheslav.shapilov]

Smoothing is a bit different thing. Only post processor finally knows about machine kinematics and how it is controlled. So, it should know, how small these steps should be to fit moves in tolerance. This means, that linearization for non-TCP machines should be done in post processor. But it does it for singularities only, not for all moves.

BTW, could you share your example and post for the reference?

[lorNZLYK]

Hello,

Thank you @viacheslav.shapilov. 

Yes I understand they are different things.

Meanwhile I did some other tests that might have revealed a bigger/different problem. 

On a more complex toolpath, even with a S&S with Smoothing set to Evenly spaced Points, the movement of the machine isn't perfect. 

The PP is the Standard Fanuc Turn/Mill, slightly modified in regards to some M codes.

Cheers,

Luís R