part number woes 1

[joebk]

I am not sure if this is the right place to ask this question but here goes...

We produce a part for customer X. They supply us a component used in the final assembly for free, since they are buying it back after all.

We have found that it would be to our advantage to use the part in another assembly so customer X has now quoted us a price for purchasing the parts but will still supply parts for use in assemblies that they purchase for free. The final assemblies are totally different in this case.

So our purchasing department wants us to create a separate part number for the same darn part. So we will have one part number for this part when it is used in product for customer X and one part number when it is used for everyone else. But it is the same #$%^ part!

It has always been our cardinal part number rule that a different part number indicates a fundamental difference in design (parts are not interchangeable). So changes in vendors, prices, etc do not necessitate new part numbers.

Anybody every resolved something like this without jumping off of a bridge?

Thanks!

JBK

 

[swertel]

Yes. We kept the same part number.

Seems to me that purchasing is locked into whatever system they are using and want engineering to make their life more difficult (breaking the "rules") so purchasing doesn't have to.

Personally, this is a job for your inventory control / ERP system to handle. You should be able to inventory the same part number under a different "work order" in order to separate the quantity that belongs to the customer - the units they provided for free to be used in their assemblies, and the quantity that belongs to you - the units you purchased from them to use in assemblies you will sell to other customers. If you don't have this ability, time for an upgrade because it probably won't be the last time you come across this situation.

A little fuel for you side of the discussion.
Let's say you create a second part. The drawing or requirement document for it is going to be exactly the same for both. So what in your engineering print is going to differentiate the one you buy vs. the one that is customer furnished? What is going to prevent someone from using the customer furnished part number in the next machine you design for another customer? I think if you create a second part number for the same part, you are opening your system up to a world of downstream problems.

What configuration management system are you using to differentiate final assemblies? For example, you sell Assembly A to Customer A (who provides you the part). Later, Customer B really likes Assembly A and wants to buy it. Do you now have to recreate Assembly B exactly like Assembly A except with the purchased part called out in the BOM instead of the free part? That's a lot of engineering time for nothing. And now you fabricators have to follow a second print and set of instructions to perform the same actions? That'll get confusing. What if there is a revision to one part/assembly but that revision didn't get incorporated onto the duplicate? What happens when fabrication just got done building Assembly A and then have to immediately build Assembly B that didn't get the revision, yet all the tooling and fixturing has been converted over?

I could go on with a bunch of what-ifs. Seems to me you better hold fast to your current standard operating procedures. That is, after all, why you have them.

--Scott

http://wertel.eng.pro

 

[joebk]

Oh believe me, I have made all of those arguments and more

I think it is sometimes nice to know other people out there have to fight the same nonsense, thanks!

 

[mrMikee]

I had something similar. Engineering had numbers for parts and assemblies. To buy one of the parts or assemblies on the outside we had to give it a purchased part number which then required maintaining two numbers with corresponding revisions. Finally they upgraded the BOM software and started buying parts on the outside using the engineering numbers. One day the accounting guy called me and said he was getting costs twice what they should be. He concluded that when he had to buy a part we had previously made he had to delete all the items in the BOM so he wouldn't get these costs to add to the price to buy it. I suggested this was ridiculous and he should call someone who knew how to run our system. It never did get straightened out.

-Mike

 

[tloutzen]

Re-identification for a vendor part using your own company number is fairly common practice, and is almost always required by defense contractors. Get a copy of ASME Y14.100 and it will describe this method for you. There are good reasons for using this method - one thing it provides is if you create a Vendor Item Control Drawing, you establish the requirement for the part; the drawing lists the vendor name, address, CAGE code, and part number. If this vendor goes out of business, or cannot supply the part, you add another vendor and their part number to your VICD drawing. This way you do not have to write change orders to update parts lists that call out the vendor part number. Your parts lists would list your company drawing/part number - and that drawing could list multiple sources for the same part (assuming it is a common part like a screw or resistor). On a VICD, the vendors are listed under SUGGESTED SOURCE(S) OF SUPPLY.

 

[mrMikee]

tloutzen,

What you say makes sense to me as far as I understand it. If I were to set up another BOM and drawing system I would look into the ASME specs. I think however that management systems used by General Motors for example is probably more than is required by small job shops like where I work. I am familiar with part numbers for vendor items and the need not to rely on specific vendors and their part numbers. My problem was assigning purchase part numbers to something that already was in the system with a number and BOM (a weldment for example) solely for the purpose of accounting and invoicing. It seemed unnecessary to me but I suppose it could be made to work with the right discipline. The result where I worked was confusion and problems keeping revs coordinated.

Regards,
-Mike

 

[EDykstra]

This issue happens everywhere - but for different reasons than the 'free part' issue you describe. The solution is to separate the Engineering BOM from the Purchasing BOM. (With what ever manual or PLM solution you decide to implement) It is a HUGE expense to have multiple part numbers for the same part.

One company I consulted always single sourced. We convinced them to create a Purchasing BOM to isolate the Engineering Department from revising drawings etc for price and supplier changes etc, which have ZERO effect on the part other than to change the revision. Our argument was that the new directive was to source to at least 2 suppliers, which, if we continued down their path and logic, would double the time billed to engineering changes, for absolutely no added value to engineering. (Actually, it would create more than twice the effort, since not only do you have to do it twice, you also need to make certain both are exact and in synch.)

The solution can be as simple as adding a vendor number suffix to the part number on the purchase order. Then, the purchasing department can easily deal with the changes without impacting engineering.

I'm not sure if your company plans to multi source, but that would be a strong argument to support your case. Especially, if you have metrics to show the current costs for engineering changes.

Eric