Part axis moving when part moves????

[dtwo]

How can I prevent the part axis from moving when I move the part with the compass, assembly constraits, etc?

My goal is for every part in the assembly to have their axis coincident with all other parts regardless if I change their position.

 

[fighterpilot]

Part axis of an individual part? Shouldn't it move with the part if it's related?

In assembly if you use the coincident constraint you should get what you would like to do.

A visual description of what your're trying to do would help.

--
Fighter Pilot
Manufacturing Engineer

 

[dtwo]

Let me see if I can explain further. Our standard requires all parts to be designed relative to "car coordinates" which is a 0,0,0 position on the car.

If a part is created in car coordinates where the part axis is coincidient with the car origin (0,0,0) then is moved, the part axis now moves from the car origin.

 

[fighterpilot]

Ok, now I understand. We design aircraft and related and work in the same 0,0,0 system

However, I never understood that system because it does not take full advantage of the assembly contraints available in the software. In my previous career I worked in machine tool design with Pro/E and we did use a lot of assembly constraints. It was very powerful and completely understood.

Do you have a skeleton assy of the major items in your assy? Lets assume it's a car. One axis could represent each axle of the front and rear axles spaced at some distance from each other in the top level assy. Thru these axis would pass three datum planes. Each one of them would be a subassembly in itself. So someone could take a subassy, design parts relative to that axis and then still use assy constraints between the parts in the subassy. In the upper level assy if the axles moved apart some distance everything would still be related to the smaller subassys.

Hope this makes a little bit of sense.

--
Fighter Pilot
Manufacturing Engineer

 

[ferdo]

This is an old thread (

http://www.eng-tips.com/viewthread.cfm?qid=115631

) somehow related with this one

Regards
Fernando

 

[catiajim]

If the requirement is to have the parts in "Car Coordinates" (or Aircraft Coordinates), then they must be built there in the first place.

In addition to Fighter Pilot's concern for not using the power of the software, it is generally a bad practice in V5.

The big problem in a PLM world, is for which configuration or product? If parts are common to multiple products, or move to different locations in different configurations, then which one do you build the part in?

It took us a long time to overcome this hurdle, but we finally convinced our data customers that they only way they could guarantee that the part is in the correct coordinates for a specific product/configuration, then they needed to open that part in that product and configuration. Today, the designers build their parts in whatever location is most convenient (usually in the original Product Coordinates), and then use the software tools to move the parts to their assembly location when working with the assembly.

I'll get off of my soapbox now

 

[dtwo]

Thank you all for the feedback.

It's good to see from other perspectives.

 

[catiajim]

Typically, our users build the parts where it is most convenient. That usually means that the parts are in the original location (i.e. A/C Coordinates for the initial design). That being said, if the product changes after the initial design (i.e. if changes are made to the prototype, or if the product is moved or modified afterwards, the parts are not revised to re-locate them if there are no geometric changes to the part. That is why we had to convince the data customers that they couldn't trust the location of the geometry within the individual part.