7 Replies Latest reply on Oct 29, 2014 10:36 PM by Brian McEwen

    Revision control for long term changes.

    Steven Dod

      We have been using EPDM for about 4 years now.  We have the process down pretty well.  The issue we keep running into is when we have a change that takes a long time to implement.  Things such as lots of stock to use up, or the part takes 6 months to make, so on, so forth.  From an engineering standpoint we request a change, make the change, approve the change and release the drawing.  Now it is in the hands of the ERP/MRP specialists to handle the business side of the change.  Lets' say we have a 4 month supply of Part A and we need to use it up before we can switch to Part B.  The drawing is released so the engineering is done but they have to hold the change until Part A is gone.

       

      Now customer service comes along with a problem that needs to be fixed right away so the engineer requests another change to remove Part C and replace it with better part D.  The drawing is approved and all is right in the Universe.  But wait.  ERP/MRP is still sitting on the previous revision waiting for a use up to complete.  They cannot implement your new change until the other change is done.  What now?

       

      I have searched high and low but have not found any guidance on how to effectively work around this.  Let me know what you think or how your company handles things like this.

       

      Thanks,

       

      Steve

        • Re: Revision control for long term changes.
          Daen Hendrickson

          Steve,

           

          A good book covering this is:

           

          Engineering Documentation Control Handbook

           

          By Frank B. Watts.

           

          It has been a while since I read it so my paraphrasing might not be exactly on.

           

          He would say that a portion of the change control process includes the disposition of the current revision. It appears that the disposition is to "use until gone". He would also say that the change control process needs to include all the decision makers. It sounds like the disposition decision is separate from the design change decision in your company and that is part of the conflict. And he would say that each change order is for a single change. Not necessarily a single part, but a single change. ECOxxxx changes material from aluminum to steel. This is a single change that affect many parts. All those part changes would reference this single ECO.

           

          In a perfect setup, the decision to change Part A to Part B with the disposition of Part A to "use until gone" is a single change. The decision and need to change Part C into Part D with disposition of Part C to be "remove remaining from stock/scrap" is an entirely different ECO. This should have NO bearing on the timing of the changes for the earlier ECO - UNLESS there is a specific design requirement that links the two such as the new Part D can only be installed if Part B is also installed. In this case the new ECO is superseding the disposition of the earlier ECO. The new ECO needs to recognize the need for Part B and that Part B is currently driven by the earlier ECO.

           

          The business side needs to be included in the same and only change control process. That provides them the input that their decision to save money on one hand is delaying money saving or strategic market changes on the other hand.

           

          I don't have a slick work-around for you. The change needs to be in your company's process.

           

          If you get a chance, take a look at the book. Parts of it are a little dated - it seems from an era of paper and 2D electronic drafting. However, the approaches are well thought out and SIMPLE. The underlying idea is that simple means fast and it means the process will be followed instead of "worked around" to overcome its deficiencies.

           

          Daen

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            • Re: Revision control for long term changes.
              Steven Dod

              I had run across excerpt from this book and thought about getting it.  It is helpful that you have endorsed it.  I am surprised I cannot find more discussion about this issue because it seems to me that many people would run into things like this.

              • Re: Revision control for long term changes.
                Brian McEwen

                I recommend the Frank Watts book too. It has some good principles and something to compare to even if it does not all apply to you.

                 

                We in Product Development recently got Manufacturing Engineering filling out the Materials Disposition form - that way the people often requesting the change (and they are concerned about product cost) decide if we scrap old stuff or use it up.  Hopefully that helps improve the communication. But we have some of the same issues. It would be nice if our ERP system supported future a BOM feature, so the new BOM that is waiting to be implemented could be referenced, but I think Materials just waits to change it.

              • Re: Revision control for long term changes.
                David Heverin

                Steve,

                 

                Daen refers to an important part of any ECO/ECN form.  That is the "item disposition".  If instructions are included on your form as to what should be done with remaining stock, parts in process, future parts, etc. then there is no question.

                 

                We also run into people who create the change documents wanting to try to do too much at a time.  It is usually easier and simpler to have each change document be discreet and perform only one action at a time.  True, it can create more changes in number, but each one has a much better chance of being understood and implemented correctly.

                 

                I also agree that it is imperative that the procurement (purchasing) and planning (MRP) people be part of the process.  In our change process we have representatives from each of these groups sign-off on all of our changes so that they are aware of WHAT is to be done with particular in-stock parts.  The REAL challenge we face though is getting people to ACTUALLY READ THE ITEM DISPOSTION  portion of the change documents that circulate! 

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                  • Re: Revision control for long term changes.
                    Steven Dod

                    I agree completely David.  We mark everything we change with a disposition.  In the past there has been a significant disconnect between Engineering and Purchasing.  There is still a significant gap even today but we are trying to take measures to close this gap.  Many of our long lead changes are affected by purchasing buying a years worth of parts at a time.  At this moment we do not have an effective mechanism for marking a part in our EPR system "under change, do not order".  Engineers are not give any access to EPR outside of reporting services.  Basically a look but do not touch scenario.  I appreciate your comments.