5 Replies Latest reply on Nov 5, 2018 2:09 PM by Barry Watkins

    How do you revise assemblies in PDM?

    Logan Pegler

      Our company is such that we design equipment and have external contractors manufacture it. Due to this it is very important that the revision of parts and assemblies is correct and communicated clearly to reduce chance of error during manufacturing.

       

      In the past our company has followed the process that when a part is revised, two assemblies above the part are revised also. This means that any assemblies above (some of our assemblies may have 6 or 7 layers) are not changed.

       

      Since implementing PDM early last year, this method has been up for debate and we still have not got a decisive, effective way of revising assemblies that works well with PDM.

       

      We would like our manufacturers to access our vault and so would have access to the BOM in explorer, this shows revisions, which is great. We also thought about having this in the BoM in each drawing which offers the same behaviour. However following the previous revision scheme means that subassembly BoMs can get out of sync. E.g Part X, Assembly X and Assembly Y are revised to Revision B. Assembly Z which references Assembly Y, still shows on the BoM that it uses Assembly Y - Revision A. This means that we would practically have to revise each and every assembly above a part for even a minor change.

      A version update of a released assembly might be a better way to get this BoM to update, however this would complicate the workflow, as we would have to be careful what files we update, vs what get sent through the revision process.

       

      Does anyone deal with this in a different way or have any smart tips to align the revisions listed in assembly BoMs?

        • Re: How do you revise assemblies in PDM?
          M. D.

          My tip is have the contractors delete all files from before and only use your current prints.  I don't see any reason for them to store all your past rev's.  But that's just me.

           

          We don't have rev's listed in the BOM or part number.  The contractor just makes everything according to our latest package we give them.  Say 100560 was revised.  It doesn't matter whether it was revised or not they look at the drawing and make it to spec.  They shouldn't care what rev it is, they just make it to print.

            • Re: How do you revise assemblies in PDM?
              Logan Pegler

              The problem we have is that at any one time we might have 20 machines being made. If a design change happens while that occurs the contractor needs to still access the previous release to finish these, but then order components for the next batch with the new drawings.

              We also discussed having an update release schedule which might help deal with that situation.

              I agree that there is no need to keep earlier revisions than current and 1 earlier for this purpose.

                • Re: How do you revise assemblies in PDM?
                  M. D.

                  I see your predicament.  Honestly the easiest thing may be to renumber everything.  The type of numbering system we are moving to is xxxxxx-x-x...  So lets say the old package was 100987 and each sub assy was 100987-x and each part in the sub assy is 100987-x-x.  For the next generation of machine you could call it 100988 and the -x's are the same as in the old version (or updated, up to you).  This way every single part is renumbered and hopefully impossible for them to mix and match things.

                    • Re: How do you revise assemblies in PDM?
                      Logan Pegler

                      Yeah for design changes we keep the same part number and increment revision if the part could be retrofitted. Or a new part number if the part won't fit an old machine as it requires other changes to work. I'm sure this is stopping some of the issues that come up. But it does still mean that assemblies further up the tree in PDM can still reference an older revision of a part in their BoM than the currently released revision of the part which is causing some confusion.