Absolute Axis System in Part

[drkwing]

Hi,

When a new part is created in Catia, I can't see an absolute axis system in tree.

In some of the documents I've seen, it says "when a new CATPart is created, a default axis system is created positioned on the origin of the part at the intersection of the default XY, YZ and ZX planes."

Is there an option regarding the creation of absolute axis system during the creation of a new part? Or how can I create an absolute axis system?

Kind regards

[MrCATIA]

INSERT + AXIS SYSTEM + OK will insert an axis at the part origin for exisiting CATPart files.

To set the default mode for new parts, use TOOLS + OPTIONS + INFRASTRUCTURE + PART INFRASTRUCTURE, click the PART DOCUMENT tab and turn on the option to CREATE AN AXIS SYSTEM.

Some companies hardly ever use Axis Systems, while other company methodologies are based on Axis Systems for everything. What does your company prefer?

[Cadop]

If you don't use the Axis system in Assy. it probably will throw the CMM verifications off. Parts may have the same origin (0,0,0) but for some reason they are not located in the same place. That's when you have to use Axis to Axis, so every origin is in the same locater.

[MrCATIA]

Which CMM software do you use, CADOP? I used to use VALISYS, and it was based on the Datum system, not the part's axis system.

Also, I don't understand your comment about AXIS-AXIS transformations, and aligning all the parts in an assembly to the same origin location. Could you explain this in more detail

[Cadop]

I've had to import parts to an assembly and even though they had to same origin (0,0,0) when imported they didn't fall in the same location. But when verified they both read (0,0,0) The origins of the parts where about 2mm away from each other, throwing the nominals off on the one part of the assembly. So I had to add an axis system to them, and Axis to Axis them in GSD to locate them to the same origin. The CMM will take the origin of the part wich it currently working on, so it looks like a manufacturing defect. Start an assembly and import some parts with the same origin (0,0,0) add and axis system to them and see if they perfectly match up. You should know that a 1mm difference when located 2 feey apart could cost a lot of money.

[MrCATIA]

Interesting. Thanks for sharing your process, CADOP, although I'm still not sure about the AXIS-TO-AXIS transformation to move parts.

And I'm puzzled why the part didn't position itself at 0,0,0 when you first inserted it into the assembly.

I was always taught the part origin didn't really make much difference. Just use Assembly Constraints to position parts with respect to other parts. Especially when it is so easy to inadvertantly move a part when it's not constrained.

But I never considered the effects this would have on CMM processes.

What do you do when the same part is used multiple times (and at different locations) within the same assembly?

I guess this proves there are always more than one way to do things. Interesting.

[Cadop]

I added a pic for you. Note that on the left that there are 4 axis pionts whith 0,0,0. SO in total there are 5 with all the same origin. When you activate one part it will tell you how far away the next origin is, but when you activate that part Catia resets to it's origin. This drove me nuts for two weeks wondering why we verified the parts indvidually the passed but when assembled the were all off, and I knew IT JUST COULDN'T BE THE CAD, well just because..... LOL

[Cadop]

Oh ya, as for why to use axis to axis to move parts. If they are created in position - axis to axis is the easiest way to place them in the right spot with the correct orientation. Cheers all