Revising a WT-part without revising related CAD objects

[Lena_428]

My colleagues want to revise some WT-parts and make changes in the BOM. The WT-parts have related CAD-objects, but these will not be affected as the BOM change is not showing in the CAD models and the drawings. The BOM update is to change from one grease to another. The job will take many hours if CAD objects needs to be revised and customers needs to approve a drawing that have not visually been changed. So my colleagues want to revise the WT-part, but want to exclude the CAD objects from revise and Change Notice. The result will be that the revision for the WT-parts will differ from the CAD objects.
Me, as an administrator say that's not good to do, as it will create problems in the future, but have no more argument to explain why we shouldn't go this way.
How do other companies do? Can anyone help me explain which situation we will end up in, if I allow this. 

[avillanueva · Accepted solution]

Great question. Fundamentally, think of the physical item you are building. What is its revision? Does it derive from the WTPart? From the CAD model or Drawing? What revision do you carry in your ERP system? Windchill can handle, better than before, having related items differ in revision. So long as the business can handle the complexity of all the items floating at different revisions, no issue there.  It makes Configuration Managements job a bit harder because you need to keep track of the links and ensure things are correct.

What I mean about this is take the final product? If I change the CAD model, drawing or BOM, I could potentially end up with a different item. If we are tracking revision to the WTPart, changing the drawing would not be reflected, no change to WTPart, BUT could end up creating something different. 

For my company, we sync revisions. Change one, change them all. In the end, its a simpler process to follow and it means there is only one answer when someone asked what the revision of a physical item is. If you seeing "hours" to update CAD models and drawing to change grease and something that is not visual, they are either blowing smoke up your rear, lazy, or the process is broken. Revising those items with no change here takes 2 seconds.

[BenLoosli]

We keep the revision level of the CAD document and the WTpart to be the same.

In our assembly structures, we have items like grease as a Bulk Item in the CAD assembly. Our CAD assembly drives the WTpart BOM structure. They must be in sync, change in CAD and it changes the WTpart. If there is a change that MUST be made at the WTpart only level, then an admin must do the change since they can do it without revising the WTpart.

[Lena_428]

That's what have crossed my mind, to do the change as admin.
I get to keep the sync between the WT-part and CAD objects but will still get the correct item in the BOM. 

[avillanueva]

Careful what you sign up for. You will forever be fixing things.

[Lena_428]

😂

[jlecoz]

First I agree with all that has been said about synchronizing WTPart and CAD rev. The WT Part rev is the reference, If you don't do that synch it means that Doc or CAD doc has "internal" rev (not shared with ERP/manufacturing/service).

One key reason to have both in synch is if you have a WPART Released (not modifiable) and a linked CAD Doc that you modify, you may not be able to check in your CAD modification, depending on how you processed the revision between WTPart and CAD Doc. This is because when iterating a CAD Doc Windchill will try to update the link on the WTPart (iterating it) that is not modifiable. If you desynchronize modification can occur on WTPart or CAD only with the risk of such conflicts. Desynchronizing  adds complexity when doing modifications