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New revision vs new partnumber

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Participant

New revision vs new partnumber

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

16 REPLIES 16
Highlighted

RE: 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.

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RE: New revision vs new partnumber

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.

Highlighted

New revision vs new part number

That's a can of worms you're opening there.

We had many, many discussions on this subject here internally with our SAP guys, really.

In Engineering we generally maintain the rule: If the part is backwards compatible you are allowed to revise.

But people often mistake backwards compatibility with upwards compatibility (interchangeability)
A revision change does not necessarily have to be upwards compatible.

So we have many situations where the new revision could be used in all existing machines,
But old revisions can not be used in newer versions of a machine.
(e.g. a bracket has two holes added to be able to attach a new option of the machine. Backwards compatible, but not upwards).

To me it's obvious what the advantages are of a revision change: all master data of the item is kept, supplier information, manufacturing information, price information, where used data.
And there are a lot of out of the box processes (e.g. phase-in/phase-out) available for revisions.

We use effectivity on series level. So the new revision must become available with the new series of a machine. The old series can use up the old revision.

We CAD/PLM guys are pretty capable of managing that kind of revision changes.

But in ERP that's a whole different story.

We are on the verge of migrating into a SAP system in which they did not implement Change Management and therefore incapable of properly managing revisions.
The revision is then more or less an attribute in the master data. There is no way two manage two separate revisions of the same item.

After all the discussions (me trying them to implement the Change Management and Series Effectivity in SAP) this eventually boiled down to the point where we will add the revision letter to the item number in SAP. That will enable us to manage each revision independently. They are now working on tools to easily copy master data from one item to the other. An ugly work around because they did not want to change the current SAP environment used in our sister companies. Deep sigh.


Kind regards,

Olaf Corten




Olaf Corten | CAD/PLM Manager

Besi Netherlands B.V. | Ratio 6| 6921RW Duiven| The Netherlands
T: +31 26 3196215 | M: +31 644548554
- | www.besi.com



From: NacNac MOTT <->
To: -
Date: 11-02-2014 23:34
Subject: [solutions] - New revision vs new partnumber



Hello guys.
Hopefully I am hopening pandora's box Smiley Happy
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 in particular (or maybe there is a third one)

Thanks


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Highlighted

RE: New revision vs new partnumber

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 ?

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RE: New revision vs new partnumber

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.


Highlighted

RE: New revision vs new partnumber

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


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RE: New revision vs new partnumber

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


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RE: New revision vs new partnumber

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 🙂



Highlighted

RE: New revision vs new partnumber

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

Highlighted

RE: New revision vs new partnumber

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


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RE: New revision vs new partnumber


That works for a by-glance comparison of nominal geometry, but not tolerance variations and other engineering analysis needs to validate that the new part is sufficiently interchangeable if it is changed in some non-trivial way.


x

Highlighted

RE: New revision vs new partnumber

Hi David,


I was working with our checker with CreoView MCAD compare. It does work with drawing dimensionsand GD&T features when appearing on drawing views. Are you only using 3D model comparisons or 3D drawings? I haven't tried the 3D drawings yet. I'll take a look when I get the time.



Patrick



In Reply to David Schenken:




That works for a by-glance comparison of nominal geometry, but not tolerance variations and other engineering analysis needs to validate that the new part is sufficiently interchangeable if it is changed in some non-trivial way.


x


Highlighted

RE: New revision vs new partnumber

I'm refering to the way the next assembly functions with different versions of multiple copies of the same part, not the documentation for the part itself.Example:replace one sparkplug in a car engine with a new version and see if the motor runs rough because the spark ignites fuelearlier or later on the new plugthan the remaining old version spark plugs.



It's one thing to verify interchangeability when an item is replaced in its entirety, which Pro/E can deal with. It is another when the item, because it the same part, but different versions, which Pro/E can't deal with. This is the advantage of multiple part numbers - any part can be installed at any time, without regard to the presence of other parts. If only using revision one is restricted to only having one version available at a time.


As to Creo View, it can view the drawing and a static picture of the model, but it can't show what the model is like at dimensional tolerance limits. If those limits are revised, but not the nominals, it is possible the new part will not function the same as the old one and there is no analytical method in Creo View to tell that that is the case and what the result might be.


x

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RE: New revision vs new partnumber

I believe in Revisions control and not new part numbers as the general rule.


But it boils down to how you do business, what type of products you make, how are they packaged together, etc.


A company must always do what make the most sense for thier particular situation.


We easily manage our product designs with revisions and never create new part numbers for design changes. There are rare cases where we may do this, but it must be approved by a comittee in order for it to happen.


Olaf mentioned all the great benefits of revision history so I won't repeat them here. If your product line is difficult to manage with revisions, then you must make adjustments that make sense for your company.


I think you should always control designs by revision, unless it's not possible. In that case you need to do what works for your company and just make sure there is no confusion about it. As long as everyone is in agreement with your process and there is no confusion, anything CAN work.


ΜΟΛΩΝ ΛΑΒΕ

Highlighted

RE: New revision vs new partnumber

Hi NacNac MOTT,


Here's another question guys who believes the CAD files represents the actual materials. You mentioned that you place family tables for material changes and not fit changes. How far does CAD go to manage all the "non-3D" attributes of a material?
Should it be placed in the Windchill material/Part object? If not,can the CAD file become a generic 3D feature based object that can be used anywhere. We talk about proliferating CAD files or information. My hope in the future is that 3D CAD files are just 3D CAD files and the metadata of the information is kept in another object. I would love to keep information in its small sets where it can be reused and reassembled to generate unique object. Why not place this information in PartsLink Classification?


Many reasons to revising a CAD file after officially released beyond fit, form, function changes:



  • Sometimes in CAD there is so many inter-object relationships and dependency that it is a package of files

  • small changes in the CAD file like a layer, adding a datums, etc

The funny thing about communication with vendors and other departments intrusting in what you changed after release. Most cases, they usually want a new revision of files no matter what becase there was a different in the files you sent them.


I took a look at your product definition slide. I'm more accustomed to looking at a product definition like a 4 sided piramid. each side covers:



  • Marketing and Customer structures with requirements

  • Design structure with changing revisions

  • manufacturing and service structure with changing revisions and different plants/lines and effectivity

  • purchasing and supply chain structure with changing revisions to the manufacturing

Each side you can draw multiple lines from the apex down to the bottom generating a specific baseline of information. The middle volume base is all the documentation with its own revision control.


That's my view of the business solution regardless of tools.


Having fun as always,


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


Highlighted

RE: New revision vs new partnumber




Hi Nacnac,


Maybe I can still add something to this thread.


Since the discussion highly depends on the business you are in: we are not in the military business, nor in aviation, nor in nuclear, we develop, make, sell and service highly complex industrial equipment, involving mechanics, electronics and software.



1/


I think you have to consider where you are in the process of your component, and what you want to
achieve. Our machines can be 20 years old and more, we have to provide service for very old machines. So, the investigation of backward compatibility (BC) is of extreme importance for us. But BC depends on the 'where used' of the
component. The same component can be 100% compatible in one BOM, partially compatible in another, and not compatible
at all in a third BOM. I don't know if revising your component will help you to model this complexity? I have no experience with 'substitutes and alternates' in Windchill, I think and hope it's meant to tackle this.



2/


On the beginning of the life cycle of a design, in Creo, we recommend our designers to always revise CADdocuments, unless the older revision is kept alive parallel to the newer revision for a longer time, and it's likely it will change in parallel. This way, we try to keep the top-down reference structure in Creo intact, preserving the design intent of the
machine. When you make copies of CADdocuments, because the change is not form-fit-function, the new CADpart will replace the old CADpart in its CADassembly, so jeopardizing the design intent. That's something we want to avoid by all means.


But our designers have learned to associate a new part (with new revision) to the newly revised CADdocument. This way, we use the association between CAD and WTParts as mapping table between CAD and ERP. Of course, this is only possible if you avoid naming your CADdocuments according the WTParts.



3/


What exactly are you going to revise? Only the component (WTPart), or always all the CADdocuments along with the WTPart? A daughter company in the group chose not to release drawings, only to release CADcomponents and WTParts. Hence, they don't need revisions on drawings. Of course, they make use of the iteration history of the drawings. But they are fine with it.


At our site, on the other hand, we are considering to allow changes without revisions, just a simple 'set state' and off you go. Although there is the iteration history as well, and basically, revisions and release procedures are meant to trigger actions in the organisation, I'm not in favor of that approach.



4/


When you change a component, what do you do with the upper level components? Suppose, there are 12 first level
where-used's, 5 of them are not used anymore, 7 of them are. Those 5 will be left behind, I think, but those 7 all have several upper level components as well 😞


Our approach is to propagate the change up to the level where components are stored in an in house warehouses. New numbers always get own locations in the warehouse, I suppose numbers with revisions will be treated the
same.



5/


In contrast with PLM, you can say ERP-systems are around since ~30 years, and have reached a fairly status of functional maturity. As mentioned before in this thread, SAP is not built to cope with revisions. We are trying to get up to speed with AX, but revisions are also for AX not the strongest point. Maybe PLM and ERP should be tied together intimately, leaving the revisions for PLM.


But is this an option? Are there examples for such an implementation? The main problem I see is that ERP should be able to schedule both revisions, to phase in and phase out the new and old component.



Some thoughts, Hugo.



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