Transform question

[Curty_82]

Thats what I currently do.. I just hate programming in aero coordinates..

[Matthew D. Hoedeman]

Thats what I currently do.. I just hate programming in aero coordinates..

So align in aero-space (iterative OR cad=part), then do a local co-ordinate (NO iterative, NO cad=part) and you can then program off the cad to the local, then export to the aero-space. Trust me, this leaves the cad data in the aero-space (and you have the aero-space alignment) but all YOUR nonimals will be to the local co-ordinate.

For example, if you have cad data for a 3-2-1 block (something simple) that has the 'bottom-left-front' corner defined at 3829.348, -295.917, 193.983, you can align to the cad data (either iterative or cad=part) the right after that, do a local alignment of that corner setting XYZ zero to that corner, NO cad=part, NO iterative (so you have to do a 3-2-1) and you can click on the cad and it will "APPEAR" to be in the local alignment co-ordinate system.

[Curty_82]

I know thats what i do.. so i guess im really only programming in the aero for the iterative.. Thanks again for all your help Matt.. BTW happy friday..

[DaSalo]

For some projects where the aero csys is just totally screwed off relative to the model and I don't want to screw around with adjusting the machine axes to get normal to the CAD as it will sit on the machine I'll do the following:

In CAD system:
1: Create a 1x1x1 cube at the absolute csys (aero csys)
2: Move my working csys to something convenient for CMM programming
3: Export out an IGES file of my part, fixture, and the absolute cube relative to my convenient csys from step 2.

In PC-DMIS offline:
1: Use the cube at the aero absolute csys to define generic features for alignment or Xact datums.
- Measure a plane on one face of the cube and then use the nominal data to create a matching generic plane, etc.
2: Once you have generic geometries defined at that aero csys you can use them for datum features for Xact measure or to define a csys to csys translation alignment.
- Use an iterative or CAD=Part, or whatever to align to the your CAD absolute, which is the nice convenient csys that you defined in step 2 above.
- Do all of your programming relative to this convenient csys.
- When ready for reporting create your generic features defined by the cube at the Aero absolute. Create an alignment to those generic features. This translates your alignment from wherever it currently is to the aero absolute.
- You can then report everything out relative to the aero csys while your entire program was all relative to something convenient for CMM purposes. Having that cube there also give you a nice visual of the relationship between your programming csys and the aero csys so you can always see exactly what is going on.

If you have access to a CAD system and are comfortable with moving coordinate systems around and creating geometry this is extremely fast and easy to do. I find it much easier than using the PC-DMIS functions for adjusting the machine axes to aline up with the CAD when the CAD comes in at some crazy angle. If you have used the PC-DMIS functions a lot and are really comfortable with them there might not be too much advantage to this method. It is just a different way to accomplish the same thing.

[NinjaBadger]

Am I missing something here?

Can you not just..

Import the model
Create your local alignment
Measure your features
Insert dimensions

This gives you a report from your local alignment

Hit F5 (setup)

Tick the Force Part Alignment in Car Body option then print the report again from CAD alignment?

[DaSalo]

The only times that I have had to do what I described in my post above are when the model is at such an odd compound angle that simply reassigning the machine axes was not enough to get the orientation close enough to get an initial rough alignment. I tried paying around with the "adjust" settings it didn't't work as expected on the first try (due to my lack of understanding) so I just went back to my CAD system and did what I described above. I'm just more comfortable with the tools in the CAD system. I'm quite sure the same thing could have been done in pcdmis.

I'm not familiar with the "force car alignment" function. How does that work?

[NinjaBadger]

Rather then explain it - just hit F5 (Setup) - then hit F1 (help)

It's an option on the general tab so the help should take you to the help page for that, click on the screen shot in the list and look for link for that option.

It explains it better than I can here but basically you align locally on the part (i.e. plane line circle) but the cad origin stays where it so, so if you report the location of the circle you used as the datum, it will have zero deviation, but the nominal and measured will be relative to the CAD origin.