Replacement parts/kits spanning from multiple levels of the BOM

[alexlondra]

I am trying to integrate the management of replacement parts in accordance with configuration management practices and Windchill.
We have replacement kits having parts from multiple levels of the BOM.
My consultant wants to insert these kits at the first level of the BOM of the end product. Anyway, It would be difficult to check if a part of a sub-assembly is also in a replacement kit/replacement assembly. Even if I introduced a service bom, these conditions must be taken into account when evaluating part number changes in the engineering bom.

Indeed, If an assembly contains a replacement part which is changed so that it is no longer interchangeable with its previous version it shall be assigned a new pin. A new PIN shall also be assigned to the next higher assembly for the changed repair part and to all subsequent higher assemblies up to and including the level at which interchangeability is re-established and there are not higher assemblies which are used as replacement parts (otherwise the customer should rely not only on the version of the product on the name plate but also on the p/n of the sub-assemblies)

I would also like to be able to have the same PIN being a replacement item only for some end products targeted to professional users. This leads to add all these items to the first level of the bom of the end product and identified as replacement items.

Have you got any suggestions/opinons as how to manage replacement parts efficiently?

 

[Finethread]

I would not include service kits in with the product BOMs as the consultant suggests. If you're using Windchill you could create an attribute with which you could associate the spares kits with the appropriate product BOM.

I have always ended up creating new part numbers for spare parts because of accounting issues. THe cost structure for a spare part is typically different than the part that's used in the product. Spare parts are ususally marked-up, they're on a different side of the ledger etc. If the product part is 12345, I would do something like call the spare part 12345S.

 

[alexlondra]

I would like to avoid creating new part numbers and managing their booms if they are not kits.
The problem is that I do not understand how Service parts affect part number changes. ( Any kind (and enlightened) soul?

When a repair part within an item is changed so that it is no longer interchangeable with its previous version, it shall be assigned a new PIN. A new PIN shall also be assigned to the next higher assembly for the changed repair part and to all subsequent higher assemblies up to and including the level at which interchangeability is reestablished. (MIL-STD-100G or ASME Y14.100-2004)

[ul]
[li]Are they referring to a service Bill of Materials when talking about assemblies or to the master BOM?[/li]
[li]Why should I include the level at which interchangeability is reestabilished?[/li]
[li]I do not understand why PIN changes do not propagate up to the end-product, how can the customer know what subassembly is inside his product? The pin of the subassembly is marked on the item itself, on the nameplate or bound to the serial number of the product by a database?[/li]
[/ul]

 

[KENAT]

"Why should I include the level at which interchangeability is reestabilished?"

So get to a level where a complete assembly is interchangeable.

If the end product is not interchangeable then the pn change goes that far.

It's all about getting to a point in the structure where the change is 'invisible'.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[alexlondra]

Hi Kenat,

[highlight]including[/highlight] the level at which interchangeability is reestablished

The part number describe only the item, so, why if the assembly is still interchangeable, should I bother to change its part number because it contains new spare parts which are not interchangeable?
In any case I should account for them in the end-product configuration.

 

[PeterStock]

Alexlondra, you are correct the level where interchangeability is reestablished would only be revised, not get a new part number. Interchangability involves the end product configuration and the use for replacements. If in the end product, the assembly is interchangable, but for replacement it is not, then that assembly would need a new part number.

Peter Stockhausen
Senior Design Analyst (Checker)
Infotech Aerospace Services

http://www.infotechpr.net

 

[ptruitt]

There are various ways to do this. I strongly suggest that you read two books cover-to-cover. First, read a more recent edition of "Engineering Documentation Handbook" by Frank Watts. Then read "Bills of Material for a Lean Enterprise" by David Garwood. Both books are essential. There are significant differences in the approaches they take, but knowing both approaches will help you understand the ramifications of your situation and how your approach will affect the company. The questions you ask need books to answer them. The Standards are important, but getting to the depth of the problem can not be achieved in this forum. I will make this comment, though: Design documents and part numbers are two different things. Any solution that does not properly account for this will take you back more than a generation in the evolution of configuration management. Disastrous implementations of PDM, Windchill, SAP... are inevitable (inevitable!) without this depth of understanding at the right places in the organization.