DeformedTree said:
Proper engineering practice is if you break "form/fit/function" you must give a new part number.
DeformedTree has pretty well hit this discussion at the 98%+ level.
Form, fit & function is the mantra ingrained into the psyche of designers & engineers and it's learned from the initial git-go...it's one of the first educational steps learned. Part number
revision level change is the indicator of a minor design change while
part number change is the indicator of a major design change. That's pretty much the standard throughout the industry.
So interestingly enough, Festool still lists the same individual part numbers used on both the old Kapex and the new Kapex on the EKAT site yet they don't list the revision level changes to those part numbers. To the uninitiated, this may seem as nothing's changed, however buried within the revision level significant changes may have evolved, even though the new part passes the fit, form & function test.
Having worked in the semiconductor arena for over 30 years we took a more transparent position. As a matter of courtesy to our customers, we would in the bill of materials (BOM) list the old part number and then also use the symbol R/B (replaced by) to introduce the new part number even if the new part passed the FF&F test. That way significant changes were duly noted.
So, if the customer looked at the original BOM and it read 12345 (R/B 12346), that would indicate to him/her that a significant manufacturing change had transpired. This approach was a simple heads-up for in-house manufacturing and a reassurance to the customer that their desired/requested/needed change had happened. A win-win for both parties.
My initial thought is that Festool is not quite so transparent in their new Kapex introduction. I really hope they prove me wrong.