New revision vs new partnumber

It depends. If the product is a throwaway then its components are throwaway also and as long as the changes don't affect the production chain, maybe it doesn't matter.

I've been burned a few times by organizations that just assume their change makes no difference and roll a new version out with the same part number. But the part doesn't fit the same or work the same. So, on my end, I have to create a drawing of their part that carries all the characteristics of their part I depend on so that incomming inspection can reject their parts when an unannounced change is made.

One thing that doesn't work well with revisions vs new numbers is that Pro/E doesn't allow an assembly to have multiple revisions of the same part at one time, making comparing old to new difficult.

Revising documents is a different matter - add new dash numbers, create new versions, clarify requirements, all good.

I just got a great image. A giant assembly, only one part number, but 10,000 different versions.

Here is my humble opinion.

You should only revise if the new revision is interchangeable with the previous revision. All other scenarios require a new part number.

If you don't follow this simple rule you have to build by version as well as part number. (not always easy when parts can't be marked with part and version number.

If you don't follow interchangeability rules, you are in effect adding the version as a suffix to the part number which is roughly the same as renumbering the part. Hence there is no real excuse for not doing it properly in the first place.

Hi Olaf

thank you for your reply. Very constructive. I noted the arguments you wrote coming from the ERP people. We have the same scenario, ERP people usually wants a new partnumber, as you said, they do not know how to manage revision or change management in ERP.

Some ERP systems have Change Management. We have SAP (currently rolling it out) and change management is not the blueprint.

It is therefore difficult as either ERP need to understand revision and this may be a big change to implement especially with people not familiar, or you stop managing the change in PLM and have a new number for everything, Not ideal either for the reason you pointed out.

I think the right balance is that if you consider that your ERP is only consider with one revision at the time (generally the latest released), you can manage your change and revision in PLM, put an effectivity dates and once at the date you push the new information to ERP. That way you do not have to worry about revision in ERP nor wondering if you could end up mixing stock.

But and there is a big But, can the business manage with only one released revision ?? If not, then it seems that you must have to create a new partnumber instead of revision.

Any more thoughts ?

Hi Martin

thank you for your reply.

Interchangeability is obviously key but as Olaf which interchangeability backward or upward ?

I agree with you, adding the revision level on the partnumber for ERP is like creating a new partnumber therefore useless.

In Reply to Martin Hill:

Here is my humble opinion.

You should only revise if the new revision is interchangeable with the previous revision. All other scenarios require a new part number.

If you don't follow this simple rule you have to build by version as well as part number. (not always easy when parts can't be marked with part and version number.

If you don't follow interchangeability rules, you are in effect adding the version as a suffix to the part number which is roughly the same as renumbering the part. Hence there is no real excuse for not doing it properly in the first place.

Hello David

thank you for your reply.

It would seem that someone forgotten to properly analyse the impact of the change, in that scenario !!!

What do you mean with the limitation of ProE ? You can configure your CAD structure to show the assembly with different version of the parts. OK you cannot open different configuration at the same assembly at the same time, but does that really matter ? You could open a different session of ProE for this for instance ?

I am not sure I understand the issue here.

btw where is your great image. I cannot find any attachment

Thanks

Hi NacNac,

I follow the standard school/methodology of CM/CMII. There is no individual component revisions orPARTS (PLM)/material (ERP)don't revise. Only documents, specifications, drawings (including BOMs) and other engineering artifacts (CAD files) revise. Based on the engineering rule (usually arcraft with so many sub-level BOMs), there is a 1 up where used BOM revision. If a component changes in the BOM, theBOM must also revise. The number of the assembly PART does not change thus no fit, form, function change. This fit, form function change is the discretion of the engineer or business. Some companies do a mass change to all documentation (BOMs and drawings all the way up like a complete package) Usually BOMs do not contain the revision of other sub BOMsin drawings. But, the revisions of BOMs do appear in ERP systems for effectivity drill down including the revision of engineering artifacts on the plant floor/line(s)or what is shipped in larger assemblies (automotive, aircraft, medical machinery)

Imagine you are going to physically stamp a part. Its really hard to restamp with a revision. You are going to have to use a non-conformance or effectivity allowance/scrap of the part. Can't really put it back in the inventory bin where other part do not have the same identification. Not all companies stamp which is true and that can be simplified. The question is how much does the company want to adhere to standard methodologies because it is simplier/efficient in their process to get the part out the door with their process. As long as they have complete traceability and accountabiltiy, they should be hopefully fine and have no issues with quality and identification of issues.

So, beyond intelectual property identification with internal OEMs, you may have different types of BOMs:

• design (ECRs, ECNs)


• manufacturing (MCRs, MCNs)


• purchasing (PCRs, PCNs)


• service (SCRs, SCNs)


• supply chain


• customer

This results in AML and AVL huge nested association between internal, industry standard and external identification. All has to be presented with supportedeffective engineering artifacts for accountability and tracebility. Some PLM and ERP systems can provide that broad range of solutions, other can't. Again that balance of what to implement. Different versions of artifacts appear in different lines, internal or external plantsdepending on its effectivity.

It sounds like you are doing some research for your doctorate in PLM. I suggest you take some CM courses and TCmeetings first to understand business requirements. Plus, you'll get to interact with other customers with their experiences. There is a lot to be gained joining and going to PTC TC meetings. Business experience feedback is way more valuable than books. I've learned from other standards like:

• ANSI


• DIN


• MIL


• AS


• AN


• ISO


• ASME


• etc

they all have their methologies of idenfication of parts and processes which some of us had to adhere in the industry of manufacturing.

It's not really the pandora's box. It's more like what a customer needs in order to do his business.

Good luck,

Patrick

In Reply to NacNac MOTT:

Hello guys.

Hopefully I am hopening pandora's box 🙂

I guess there are only two schools.

One who never revise and systematically create a new partnumber

Another who always try to revise (but if the change impact various product differently then they may "split" the design and create a new partnumber)

I am from the second school. If after the impact analysis all the impact references can accept the change, then a new revision is created. If, for sake of argument, a part is used in 100 assemblies, and for 20 of them we cannot accept the change of the part, then we create a new part. Then depending on the effort, the new part will be used in the 20 assemblies while the other 80 will get the new revision of the original parts.

I really do not understand the first school. It requires a lot more efforts. Of course when you do not have CAD (understanding 3D cad), it is relatively easy to mass BOMs, but as soon as you have to update 3D cad, this can become very complicated.

In addition, you lose the history of the part.

One of the reasons of the First school is that if after the change the part is not 100% interchangeable, it should be a different partnumber because of the risk to mix it in the warehouse for instance. My argument saying that well, when you work you should work with partnumber AND revision, but this would mean working with revision level in ERP too. Then I put forward the argument that any change as an effectivity date. So Revision B is valid up to Day whatever, and from that date you use Revision C. The Day D, depends and may vary depending on how fast you can clear your stock of revision B.

What is your views. Are you from the first school or second school but most importantly what are your argument to belong to one school inparticular (or maybe there is a third one)

Thanks

Thanks Patrick for your detailed comment.

Never heard of PLM doctorate..... I thought there was no PLM cursus at the university.

As for the research, it is kind of. A few new directors have arrived at the componies and fairly enough they question everything that has been done so far and comes with their own views and experience. I have mine too and want to consolidate/improve it.

I agree with you, meetings with peers is very good but unfortunately time does not allow as many meetings as I would like but there is internet.

Did you see the ppt I posted about product definition. What do you think ?

http://portal.ptcuser.org/p/fo/st/thread=54111

If you comment about product definition, please do it on the appropriate post but I am sure you know that. I do not want to be accuse to start another discussion on the same thread 🙂

Suppose you have a machine that has twocopies of some partand it is possible that a new revision part will be shipped to replace a broken one, or an old version part is required for a new machine. How do you verify in Pro/Ethe two different revisionparts will work together as you cannot assemble them both at the same timein Pro/E.

Suppose you want to verify in the machine that both parts interface exactly the same. Again, you cannot assemble them both at the same time and check one to the other.

You can do a model compare - you are forced to create a new name for one of the parts, but that's what you are trying to avoid.

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Hi David,

I reccomend you use CreoView 2/3 MCAD compare with different configuration publishes. As Stored versus either Latest or your ECN baseline release of your drawing or assembly parent that has different versions of yoursub CAD models.The highlighted colour will reveal the differences.

Our checker has been doing this and really likes this featureto show the differences. Beats paying for ProE just to compare which is needed by quality and production floor readers if required.

good luck,

Patrick
In Reply to David Schenken:

Suppose you have a machine that has twocopies of some partand it is possible that a new revision part will be shipped to replace a broken one, or an old version part is required for a new machine. How do you verify in Pro/Ethe two different revisionparts will work together as you cannot assemble them both at the same timein Pro/E.

Suppose you want to verify in the machine that both parts interface exactly the same. Again, you cannot assemble them both at the same time and check one to the other.

You can do a model compare - you are forced to create a new name for one of the parts, but that's what you are trying to avoid.

x