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Rotary axes outside of TRAORI transformation? CSE

Pioneer
Pioneer

Hello NX'ers ...

 

I've got a machine here that I'm creating a post and sim for - for simplicity let's say it's a horizontal boring mill with X-Y-Z geo axes, an AC head, and a B table. There is a scenario where I'd like to be able to position the B table at not only 0, but also 90, 180, or 270 degrees, and perform an XYZ+AC 5axis simulataneous operation at the new table orientation. Everything works great at 0 degrees B angle (default). If I rotate my WCS (ex G55) by 90 degrees and create the program, the toolpath looks correct for if the table and part rotated to that position. The issue is in the sim, when I actually command B table rotation (either before, or after TRAORI is activated) the offsets are affected as if B was part of the transformation, however, the GV_strSwivelingChainName is XYZ+AC. Are all rotary axes compensated for in SetKinematicTransformation? I don't expect the actual machine behavior to be like this. If so, is there a workaround? I'm in NX10 for this project, btw. I've already tried to "DetachJoint("B") after the rotation, but it doesn't seem to be a supported kernal command in NX10. Also worth noting that the machine zero is not at the center of the rotary table.

 

Any help is much appreciated!

Thanks,

John

8 REPLIES 8

Re: Rotary axes outside of TRAORI transformation? CSE

Phenom
Phenom
Considering the chain name - I assume you have a XYZ kinematic chain defined in the machine model and a device (head) with AC kinematic chain (right?) I have seen successful ISV replay for the situation you describe. We switch between two chains on some machines.
NX12.02
Windows 10 Pro

Re: Rotary axes outside of TRAORI transformation? CSE

Pioneer
Pioneer

@Study you are correct. The base machine has both X-Y-Z chain and X-Y-Z-B chain. In this case, the active chain is only X-Y-Z+C-A. Which is the reason for my confusion - as I understand it, B axis should not enter into the transformation.

Re: Rotary axes outside of TRAORI transformation? CSE

Phenom
Phenom
I would check to see if at the moment the chain is activated by traori the device is attached in the isv tab and has the kinematic chain for the device "A-C" in the model for it. Is ISV acting like XYZBAC is active or is the device and tool not being compensated as if XYZB only? I imagine the experts will chime in soon. I just thought I could ask about the obvious before then.
NX12.02
Windows 10 Pro

Re: Rotary axes outside of TRAORI transformation? CSE

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi John,

 

please add a screenshot of the kinematic tree.

 

thanks

Thomas

Re: Rotary axes outside of TRAORI transformation? CSE

Pioneer
Pioneer

KC1.PNGKC2.PNGKC3.PNG

Re: Rotary axes outside of TRAORI transformation? CSE

Pioneer
Pioneer
Thomas,

As you can see, I have both Z-X-Y and Z-X-Y-B set up in the base machine kinematic chain configurations. However, when set Kinematic Transformation = TRUE, the GV_strSwivelingChainName is Z-X-Y+C-A. This works just fine when the B axis is not rotated. It also works fine for Z-X-Y-B+A operations. If the B axis is rotated during an Z-X-Y+C-A operation, however, the offsets are negatively affected, as though it is compensating for the rotation.

-John

Re: Rotary axes outside of TRAORI transformation? CSE

Siemens Phenom Siemens Phenom
Siemens Phenom

Hi,

 

I asked for the kinematic tree and no for the kinematic chain defintion ;-)

 

Background is the following. A deselection of an axis in the kinematic chain definiton does not effect a non consideration of this axis when it moves. This axis can only be excluded (from kinematic chain definition) when its outside the part end and tool end tree.  

 

Thomas

Re: Rotary axes outside of TRAORI transformation? CSE

Pioneer
Pioneer

Thomas,

 

Sorry for my misunderstanding ... please see new attached image. I think I now understand how "B" is trapped in the kinematic tree between part and tool. Is "GV_strSwivelingChainName" then, mainly for calculations inside CSE, and doesn't have the ability to selectively ignore any of these axes in the tree? If this is the case, I don't expect it to mimic real machine behavior, when an XYZ-CA transformation is active. Any suggestions on how we can accurately simulate this?

 

Thanks and regards,

John

 

KC4.PNG

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