Software for testing pass-thru assembly of odd-shaped components

[geesamand]

The title says the problem in a nutshell.

Specifcally, I have a variety of component "A" (similar shape, various sizes) that must fit through customer's component "B" (again, similar shape, various sizes). The shape of A is irregular enough that we can carefully orient it at an odd angle and rotate it and pass through a component A that is larger OD than the ID of component B. Not all A's fit into all B's so we are making a table showing which do / do not fit.

Component A has changed in shape quite a bit since the last time this table was developed. Rather than making scale models of everything, I want to know if there is a 3D software that can take the 3D models and interactively see if they can be manipulated to prove/disprove assembly at the customer's site. I imagine that a multibody, collision-detecting, interactive, 3D software could do it. This reminds me of how Solidworks will let you assemble components with partial constraints and move things around accordingly.

Does such a software exist?

David

 

[JohnRBaker]

Yes, there is a capability like that in our NX CAD product as an additional function available with the Assembly Sequencing package.

Attached below is a video showing the 'Extraction' of, in this case, an auto radiator from an engine compartment using this function. The computation of the path and orientation changes needed to accomplish this is fully automatic and afterwards there is also an option to create an 'extraction envelope' (ie. a 3D Body, shown as a translucent object in the video) which represents the volume of space that the extracted part passes through, which can then be used for further analysis and to help make design changes.

Note that the video is only a playback of a previously computed solution. The actual computation takes a bit longer to compute, but even in the case of this example, it was only a few minutes on my laptop.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[MikeHalloran]

That's a pretty impressive capability, JRB.

That might explain how Ford came up with the service sequences for their (not quite latest) van body, where the front suspension crossmember and the firewall form a tight fitting tube around the engine.
Their sequence for removing the engine is (in part) as follows:
From inside the passenger compartment,
- remove the engine cover.
- remove the throttle body.
- remove the top half of the fuel injection plenum, saving the large paper gasket (ha!).
- unbolt the engine from the engine mounts.
- jack against the oil pan bolts to lift the engine 2 inches.
- insert 2x4 blocks between engine and mounts.
- remove the jack.
- drain the oil, remove the oil pan bolts, and drop the oil pan, saving the oil pan gasket (ha!).
- reach in and remove the two bolts that connect the oil pickup to the pump.
- drop the pickup in the pan.
- reach in and remove the two bolts holding the oil pump to the block.
- drop the pump in the pan.
- manually crank the engine to move the counterweights out of the way, one counterweight at a time, while working the pan forward and out from under the engine.
(There is not enough clearance to pull the engine out with the pan attached, and not enough clearance to pull the pan out without rotating the crank, even with the engine shimmed up against the crossmember. The pump is in the front of the engine, and the sump is in the back.)
- engage some kind of giant pickle fork engine hoist and pull the engine out through the radiator hole.
Assembly is the reverse of disassembly.
Apparently they didn't use Loctite on the pickup bolts; somewhere around 120,000 miles, they fall out.
They even got a V8 Diesel to fit in there! Again, by removing everything from the top of the engine _and_ the oil pan.

Can NX do that? ;-)




Mike Halloran
Pembroke Pines, FL, USA

 

[geesamand]

That's a very nice functionality. Unfortunately we have a 3D CAD system and for the price/logistics of NX I could buy a lot of scale models.

David

 

[mcgyvr]

If you have a 3d package then whats the problem?
Any cad-monkey can move/rotate/spin the parts as needed in an assembly to figure this out.. No need for NX.. (really cool functionality though)

 

[geesamand]

We have Pro/E, and we have done it this way. Pro/E make the move/rotate/spin process very tedious and time consuming.

I've consulted my go-to Pro/E ninjas (my reseller and Steve Smith of CADquest) and the consensus is that Pro/E requires the user to know the path in advance. There are no tools aside from visible interferences that will assist directly in finding an interference-free path for the assembly. There are some very good visualization tools but they all serve to analyze a particular assembly trajectory.

David

 

[MiketheEngineer]

Probably cheaper to make a few prototypes and see how they work?? That's how we did it in the "old" days

 

[geesamand]

Yeah that's where I'm leaning now. For the current project I estimate I'll need 15-20 rapid prototypes and up to a hundred combinations to test. It's a lot of widgets but once in hand it will move very quickly.

I was hoping for software because the same question comes up from time to time on special applications and rapid prototypes would need to be recreated with each revision to the geometry.

 

[MiketheEngineer]

3D - printer??