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Every CMM simulation goes wrong

Hello everybody,


I got a really annoying problem because I don't know how to fix that. At first I would like to tell you what I've done so far:

1. My main goal is to create a CMM template with all probes etc. like it is on the real shopfloor and then make some experiments with different measurement strategies on a test part

2. I modeled the probes with parts from a library (like they do in the CMM tutorial) and embedded them in the insp_tool_database.dat

3. I loaded the mitutoyo_crysta_123010 and assembled it with a tool rack and a modified head (like in the CMM tutorial)

4. I loaded the machine, head, rack and probes and saved all that in the ugs_inspection_templates.pax


I can load the machine or the probes and also the template is working. But now I get to all my problems:


1. When I create a new inspection setup and load my machine or use the template I created with a "PMI-part" the simulation always does many crazy things:

- I move the part with "move component" to the place I want it and then I put a touch/align constraint on it to place it on the machine table

- I use the "alignment assistant" and select an alignment strategy

- Now I link to PMI and let the program create the path automatically (I even tried  to define the path myself)

- When I want to use the "collison avoidance", it isn't possible to select any safety plane. Only if I select something like XC-YC-plane and drag it above my workpiece

- When I simulate the process (with collison partners _TOOL and _PART in the settings) the probe always runs through my workpiece or through the machine or the head goes underneath the machine etc. etc.


I have no idea what I'm doing wrong and hopefully some of you guys have an idea...




Re: Every CMM simulation goes wrong

Hello Benni,


It is hard to determine this from the information you supplied. The most common source of this problem relates to the initial positioning of the part on the machine. The initial placement must use Part Mount Junction for positioning and you must use the CADABS of the part as the part mout junction. After this initial placement you can move the part (not the machine) anywhere it is needed.





Re: Every CMM simulation goes wrong

Hi Steve,


at first, thank you very much for your reply.

When I load the machine I always use the part mount junction for positioning but I'm not quite sure what you mean with "the CADABS of the part".

I think maybe soemthing is wrong with my coordinate systems...But to be honest I'm quite a newbie in NX applications and I only learned it with the help function. If you need any specific information to determine the problem or if you have any idea where the problem might be, please let me know.

Here is what it looks like when I load the machine and move the part:



Re: Every CMM simulation goes wrong

Hi Benni,


The Specify Part Mount Junction should be "Absolute CSYS" selected from the drop down





Re: Every CMM simulation goes wrong

Benni, my previous post was in error. You should simply accept the default CSYS that is displayed. Don't move the part until after you OK this dialog.





Re: Every CMM simulation goes wrong

Mhhhh, I tried both variations but it is still not working :/



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