Part Numbers and Configurations

May 25, 2010 56 Comments »
Part Numbers and Configurations

If you do a little searching around the net, there are many discussions on the subject of internal company part numbers.  Many of the discussions center around the great debate of intelligent part numbers vs. unintelligent part numbers.  I’ll dive into that discussion a little later on.  One of the interesting things I have found is that the term “Part Numbers” often is used as a general term for internal numbers representing both parts AND documents.  Depending on your perspective, they can be quite different.

In many companies with more traditional number systems in place, the drawing number and “part number” are shared.  The difference between the instances are often “dash” numbers added to the end of the unique identifying number.  For example, a drawing number would be 200345 and the part number for the item detailed in the drawing is 200345-001.  To add another flavor to the mix, variants of the part itself are often detailed on the same drawing.  200345-001 might represent the part with a blue paint applied and 200345-003 might represent a green painted part.  This no doubt can be handy in that changes to either part can be quickly made through a single drawing.  This makes a lot of sense when you have “families” of parts that are similar and the design of these parts are tied together.

When you take traditional approaches such as this and introduce the data into a PLM system, this is where things can get interesting.  The process I mentioned above has been in use in various forms at the company I work for for many years.  Currently I am working on defining how our SolidWorks data will be stored in our soon to be implemented PLM system.  SolidWorks Enterprise PDM (EPDM) will also play a role in this process, but will mainly be used as the MCAD data vault whose sole responsibility is to track the versions of the CAD data only.  One of the things I am interested to know from some of you our there is how you are doing this.  Our current train of thought would be to name the SolidWorks model (part or assembly) by the unique identifying number.  Examples would be 200345.sldprt and 200345.slddrw.  The variants (if used) would then be stored as configurations inside the Part or Assembly model.

In more traditional systems, a revision to the Drawing would be considered a revision to the part.  When you organize  your data simply from a CAD standpoint there are many situations where this would make sense.  A “side effect” of this though is that if you have variants for the model (i.e. 200345-001 & 200345-003), BOTH variants are often considered “revised” even if the change to the Drawing only effects one variant and not the other.  This is where the PLM system can add some capability in that it has the ability to track revisions of items, yet treat the CAD data as “reference” data used to build or manufacture a part.  Essentially, it can track the part itself and the CAD data for the part SEPARATELY.  In our example noted above, the PLM system can have separate entries for the variants (200345-001 & 200345-003).  If a change is made to 200345-003 (lets just say a color change in the paint) that doesn’t effect the 200345-001, then the CAD data (200345.sldprt and 200345.slddrw) would be revised with CAD revisions synced for both model and drawing.  The revision to the items (separately stored) in PLM does not have to be incremented for the part that did not change.  (200345-001 would still be at the original revision).  The upside to this is that handling the disposition of any parts in production or on the shelf is much easier in that you don’t have to make unnecessary revisions to components that have NOT changed.  The downside to this is that if someone picks up a drawing and sees a “Revision A” on the drawing, they can no longer assume that each variant (200345-001 & 200345-003) in the form of a final “part” is at the same revision.  In this case, the documentation has been revised but only one of the the two items in PLM have received a revision as a result to changes in the documentation.  Notation CAN however be put on the drawing to indicate this, but the biggest difference is that the PLM system will have to be the controlling authority on revisions of the component itself.   This is can be a big change for anyone that touches a component during the manufacturing process.  The biggest hurdle often is training people to separate items or “parts” from the documentation used to create them.  CAD data whether it is a 3D model or a drawing is still documentation used to create the final item.

So…after this long winded explanation…I get to one of the points of this post.  I’d like to hear how some of you have dealt with this when taking your data from the CAD/PDM world into the PLM world.  In particular, are you using configurations for part variations or do you treat variants as separate part files?  I’ve read where some companies get rid of variants altogether when using PLM.  (Personally, I think we would be giving up a lot of flexibility if we did this.)  I’ve even seen scenarios where CAD data is stored as a completely separate unique number altogether.  (Although it may sound foreign to some, I can see how this could work.)

So now…I turn it over to you.  I’d like to hear some of your experiences in this area if you have the time to share it.

Stay tuned…more to come!

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  • This is such a great topic to discuss about! I for one am totally stumped on this, seriously, totally totally stumped… looking forward to any replies!

  • It seems that the one hurdle you have listed above is the potential difference in revision level between the part and the drawing. Any easy change that comes to mind is to use a different revision system for parts than for drawings. For example, parts might have a numbered revision system, while drawings use a letter revision system. This would separate the two and force drawing users to dig deeper to find the part revision. It would also let anyone in the know realize when someone did not know what they were talking about. For example, John Doe makes a comment about part 235689 at rev level C. You would know right away that John wasn't paying attention.

  • Wwhere I have worked, the part/assy is always the drawing number with a 3-digit dash number: anything ending in 1-8 is a part, 9 is a separable assy, and 0 is an inseparable assy (a strucutural assy w/inserts or a weldment, for example).

    If the parts are very similar or have the same “base”, they are detailed on the same drawing. As you know, this practice makes for easier updating/changing of components of the “base” features, and would keep the design intent intact. It also reduces the number of individual drawings you have to manage. (I have also detailed a simple assembly consisting of a few different parts on the same drawing, but that is generally an exception and I try to avoid that unless it makes sense to do it…)

    Now being more in R&D, I don't have any experience in integrating with a PLM system per se, but at my previous employer, we did have a manual system that kind of mimicked one. The way we handled components that did not change on revised drawings was to just spell out the disposition of any existing parts to use as-is on the ECN/ECO, and to make any future components to the latest revision. Would that not be an acceptable practice, or am I missing something?

    It's important to remember that in EPDM (as any PDM system) you are keeping versions, and a “revision” is simply a label that you apply to a certain version. You could possibly set up EPDM to apply revisions to configurations (the dash nos.), and then also apply a separate revision to the drawing. I would think that this would be doable, although I also think it would be a nightmare to program the EPDM workflow for this! IMHO, It would probably be much more efficient to just break the configs out to their own files and do separate drawings, even though it's more work on the engineering end…

    Another thing you may want to look into, if you haven't already: is there any possibility of hooking the PLM system into EPDM, so that it can be driven that way? We are looking into that possibility where I am currently; I know it can work, it's just a matter of if we will be allowed to do it.

  • JeffMirisola

    A part number should be nothing more than a place holder in the system. If you have a part that is available in different colors, show said colors in a table on the drawing as being available options, nothing more. Your MRP system should allow for some sort of an options dialogue box.
    Let's delve a little further, shall we? If you're designing and manufacturing, you'll generally have a finite number of color options. The work order, derived from the customer's order, will stipulate what color the part needs to be. To create a separate part number for each color variation is a waste of time.
    Now, if you're a design house and having the parts manufactured elsewhere, then you need to change things up a bit. While internally the parts may be the same, you need to be able to order the parts so that the supplier knows what to send. In this case, I would say you could still have a singular drawing. On the drawing you'd still have a table which would contain a numerical suffix column followed by its color spec.
    To tackle the whole revision thing…this is tricky. Generally, revisions occur if form, fit or function change (the three F's), when dealing with a part/assembly. Now you add in a layer of complexity by having options shown on the drawing. How do you reconcile the drawing revision and the part revision? In most cases, one would assume that there would be some sort of ECR/ECO process involved in adding/changing/deleting a color option. However, this change really doesn't affect any of the three F's, so does it, in fact, require a revision change? I would argue that it doesn't, and here's why: the color requirement is going to come from sales, not manufacturing. Sales controls what options the customer is able to order. If blue was an option, but isn't anymore, manufacturing doesn't need to necessarily know that. They simply produce whatever sales wants. Obviously, if a new color is added, manufacturing (buyers) would have to be aware of, and procure, it, but I don't see how that would necessitate a revision change.

    Sorry for the long comment…

  • Interesting idea….will have to see if the PLM system can handle different revision systems. The challenge will be cutting down on potential confusion. I think either way we do it, there will be some confusion initially. Folks are just going to have to get used to relying on the PLM for the latest information. :-)


  • Brian,

    One of the things make me want to keep my variants contained in one file is the ability to have tabulated Parts Lists. This becomes difficult for assemblies if I separate the variants into different files.

    Disposition will certainly be part of the ECO/ECN workflow in PLM. It is my hope that the information contained within those records can clear up any confusion.

    I've checked with a few of my friends who are EPDM gurus and they advised against applying different revisions to configurations. I don't think EPDM supports this out of the box anyway.

    We are exploring many options in linking the PLM and PDM. This will depend mainly on the processes we define. Luckily..both systems appear to be very friendly when it comes to sharing data. :-)

    Thanks for all the suggestions….I might be coming back to you when we get a little further down the road.


  • Jeff,

    We have to document the parts so that they work for both in house and external manufacturing.

    I think most of what you have summarized above fits into the way we will setup our scheme. It is an interesting idea to not include something like color on a drawing for internal manufacturing situations. I'll have to give that one some more thought. I totally agree on the FFF changes…the paint was just a convenient example I gave. :-)

    No need to be sorry for a long comment. I love to hear different perspectives on this stuff. Thanks for the feedback and don't shy away if you have other thoughts.


  • Thanks to all of you for commenting. Keep em coming!


  • Oh, I definitely wouldn't advise applying revisions to configurations…I was just merely stating that that could be an option for you if it came down to it. Like I said above, you would have to custom program it, and I think it would be a nightmare to do so (and also to maintain/document!); that's why I said it would be better to break them out separately if it came to that.

    I don't blame you for wanting to keep the variants in one file. That is my preferred workflow too.

  • JeffMirisola

    Whether a part is going to be manufactured internally or externally, it's still being manufactured. The information needed in either case really shouldn't differ. Your manufacturing center is your supplier, and you are their customer. If you look at it from that aspect, it should be a clearer picture. Whether internal or external, the work flow would, probably, be very similar. Production needs part 'A' and the buyer places the order, stipulating options (e.g. color) needed. Manufacturer receives the order and generates a work order, which lists the pertinent options and the part is created.
    For whatever reason, people (read: management) seem to like to over-complicate things, which I've never understood. The color of a part doesn't affect its function and, therefore, should not be factored in to the part number, in my opinion. Yes, there can be exceptions to this, but those exceptions don't disprove what I'm saying. All too often, unnecessary levels of complexity only set the table for miscommunication and/or failure.

  • Most standards, such as ASME, recommend the use of serial numbers without intelligence, but most also support the idea of smarter numbers. My experience is that there is no reason to use different numbers and revisions for parts and their documents. There is no reason to use smart numbers. However, I know that smart numbers are used successfully, and often creep into even the most basic numbering system at some point.

  • olegshilovitsky

    Ricky, I recently wrote a post about Part Numbers and Identification. This might be not exactly related to your plans, but I think, you will find great set ideas and commentary there. Here is the link –…. I hope you'll find it beneficial. Best, Oleg

  • Jeff,

    I discussed this topic a little bit yesterday with some of our PLM implementation team. Taking something like a paint spec or even a material spec off the drawing is certainly possible. A situation like that would require that the component's Bill of Materials (stored in PLM) accompany the drawing whether you manufacture internally or externally. The BOM for the component would consist of the Drawing, Native Model file, Neutral Model file (STEP or other), Material Specification, & Paint Specification.

    The beauty of a situation such as this is that the paint or material specification can be modified independently from the drawing. I've never worked at a place that does this, but I certainly see how it is possible when you are using a PLM system.

    Much of your comments centered around the Part Number theory itself. What is your take on configurations? Have you ever worked in a system that successfully stored different “versions” of a part within a single SolidWorks files as configurations – then interface that with a PLM or even ERP system?



  • You know Matt, one interesting thing that was noted in our meeting yesterday was that when you keep Part Numbers for components and drawings linked by adding the “-001″ to the unique “identifying number”, you really are adding intelligence right back into the system. (Which is something MANY of us would like to get away from.

    That thought has got me re-thinking this whole variant issue and I'm going to be running some test cases in EPDM this weekend to further investigate it.

    You are right, Smart numbers are used successfully, but it is the product of traditional paper systems. With a PLM system in place, it simply is not needed anymore.


  • Hi Oleg,

    I actually read that very article earlier this week! (But thank you very much for pointing it out to me anyway.) I haven't had the “quiet time” to sit and read through all 45 responses as of yet though. I hope to accomplish that this weekend.

    Your site is fascinating and I plan on checking it out regularly, especially with the upcoming decisions we are going to have to make for our implementation.


  • jcoeng

    Hey Ricky, have you ever read the book “Engineering Documentation Control Handbook” by Frank B. Watts? It is a great book. He has a ton of experience doing exactly what you are up against. One of my good friends has even called him up to discuss system/process design and he said he was really helpful. check out his website…

    I have a lot in my head to comment but not the time to do it :( . This is one of my favorite subjects and one that I have spent the most time researching of all CAD Admin related topics.

    I'll try to put a good response together in a few days, just been working crazy hours lately, sorry man.

  • rob

    enjoyed reading this post took a while its a long one lol it lost me at times but i think ive understood it great post

  • rob

    great atricle enjoyed reading it got lost in places but overall enjoyed it

  • robertdc554

    what a great article, thanks for publishing this. will read more from you many thanks!

  • John M

    Hey Ricky, this hits close to home. Now, add in the fact that thousands of files have been created for many years, have multiple configurations used all over the place. To add to that, the conventions are “name it whatever”, bulk load that into PDMW and have a ball trying to fix it. Some days I wonder if this stems back to the first days of users messing around with SolidWorks and any CAD system, and how the examples say to name this part “block”, and this part “pin”….not a good idea in the real world!
    We have alot of similar issues with configs,and derived configs on complex parts. With no design tables, they can get out of hand easily. So the standalone part model does have it's usage, until you need to make a similar change across the family of parts. I've talked to so many people on this subject, and most just shake their heads with OMG type of Good luck comments. Best thing is to pick a flexible method, then teach the heck out of it to everyone involved, and then Police it. There goes my headache again…..

  • bookmarking this page, thanks for the post, really enjoyed reading this

  • Marc M

    What if there were two rev systems in place, one that bumped the rev level for a variable mapped to the configuration custom properties, and the drawing associated with that configuration, and a separate rev system that kept track of those revision bumps, but recorded it at the file level of the model as a reference in a seperate serialized rev system?

    I am considering this for our EPDM pilot, which is each 'Part number as shown in BOM' field at the config level is (potentially) a part in our ERP. BOM's of an assembly are uploaded just as they are shown in SW, with all config-specific data only.

    (Typically the 'Part Number' of the config is the model name with a sequential dash number)

    The drawback is this amounts to (# of revisions per each config) x (qty of revised configs for the model) = model rev level, which is why it should be 'reference' rev level, as it could compound quickly

    Still a WIP…

  • Hi John!

    I agree…its a tough nut to crack. We have made the decision that for every unique consumable item, there will be a unique part file. It might cause us a little more work here and there, but we will have better control over our data with less likelihood of errors and confusion.

    Good luck with your PDM tasks!


  • Interesting concept Marc…

    It looks like we are going to go with a system of separate parts for each consumable item (unique part number). The major reasons behind our decision was the automation we are doing plus the potential for using the same file structure rules in other CAD systems.

    Keep us posted on how this works out for you.


  • Under Part number displayed when used in a bill of materials, the Configuration Name is selected. A bill of materials for an assembly!

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  • Website Design

    Great post!
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  • Good stuff.

    When I worked for an automotive place, that drove me bonkers. There were 7 European plants making the same finished goods and often using the same machines but each plant had a different part number or a different drawing number for the machine tools and spare parts. Add a total of 5 different languages into the mix and trying to locate a part from the machine was a nightmare.

  • Ryan

    Thanks for posting. Thanks for the ideas, very helpful.

  • We always use for parts and documents. Smart numbering would seem to overcomplicate things, but maybe we are just doing what works. Thank you for a thought-provoking post.

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  • For sure we can make lot of discussion regarding this topic. Basically, I think you explained ground things very well. I personally like using dash when numbering my personal files or anything else. Somehow it seems to me clear and easier to cope than to have a large range of numbers only.

  • There are so much information for the people!

  • Hi Jordan,
    At our company I'm working on a numbering & coding system for parts, assy's, drawings, pdf's, instruction manuals and so on!
    It is a good exercise to explore the different possibilities. I found your post very interesting and definitely gave me some inspiration to solve this complicated matter.

    Besides the information posted here, has anyone some good recommendations for literature on this matter, available in Europe? Looks like this is not easy to find without the involvement of a consultancy agency.


  • Any easy change that comes to mind is to use a different revision system for parts than for drawings. For example, parts might have a numbered revision system, while drawings use a letter revision system.

  • Couldn't you use a bar code system for all physical parts and the filing system that used to come with the CAD program for drawings? Then wouldn't it be a matter of inputting the new stock into a program like MYOB to keep track of all the stock?

  • Hi magaluf,

    Its interesting you mention that. I was talking to a friend of mine today about this and he is (more or less) doing that very same thing. It is something I am definitely going to keep in mind as we start testing next week. There really are no “technical” issue with assigning different revisions to the Item master, Model File (part or assembly), and Drawing. The problem is going to be potential confusion by users both inside and outside the company. Another factor that rolls into this is that we do have the option of using minor revisions, which should help the Item Master stay in sync with the drawings. If someone needs to add a MSDS sheet or something like that to the Bill of Materials for an item, the revision to the Item Master could be a “minor revision”.

    I'll let you know how it goes for us. One potential challenge with this method will be if the PLM system can support a “different” revision scheme.


  • I think this gets into serialized tracking…which is something we are definitely going to have to address in the near future. Most of the discussion thus far has centered around the documentation system and the revisions/part numbers to different parts of it.


  • I'm glad this has been helpful. What I have discovered in this process is that there are a TON of ways to go about it. That is why it is often a lengthy process getting a company standard defined.

    Keep us posted on how its going for you!


  • sure no problem.

  • Hey Ricky, thanks for your post! Do you know of which companies have been getting rid of the variants altogether when using PLM? Don’t know why they would be doing that and what to look into it more.

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  • H Savtekar

    please tell me how to keep drawing no for Large no of assembly.