drawing numbers NOT matching part numbers 1

[JLM-Popcorn]

thread768-239448
This is a re-boot of an old thread. I was searching for a reason for having drawing numbers NOT match the part number for an item. I'm not talking about charted drawings, drawings for parts with several configurations, etc. I'm wondering what the benefit is to have a drawing number 12345 for a part that is 98765, when the drawing represents ONLY the one part. My company used to use separate drawing numbers and part numbers, but since going to 3D CAD several years ago, and using a vault system, but now the drawing and part number match for any drawing representing one part.

I read through the previous thread (and others), and most of the conversation leans towards why matching numbers makes sense. But lots of companies had separate numbers for legacy items.

Also, when using a charted drawing, what do you recommend for a naming convention in the instance where multiple part numbers, some 5-digit, some 6 or 8-digit, need to be on that charted drawing? Example: multiple colors of plastic molded part where the drawing lists the PMS color and material for each part.

JLM

 

[IRstuff]

I was searching for a reason for having drawing numbers NOT match the part number for an item.

Sure, if you want to make it difficult for customers and employees to NOT know where to find things. If you want lots of confusion about which parts are compatible with others. If you want to maximize chaos and probability of damaging parts/systems.

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[CWB1]

I was searching for a reason for having drawing numbers NOT match the part number for an item.

IME nonstandard practices like this come about bc a manager who has always been at their tiny company thinks its a good idea, and is simply ignorant of standard practice elsewhere.

 

[cowski]

I'm currently advocating for separate part/drawing numbers. I don't particularly love the idea, but it will fix a major problem that we've created for ourselves.

The company I work for makes consumer products using various injection molded parts. If a new product release goes well, variations are created (meaning: different color parts with different decorations applied). Under the old ERP system, a part number would be assigned such as 12345 and the 12345 drawing would show all the necessary dimensions. Color variations would use dash numnbers such as 12345-100, 12345-200, 12345-300, etc. The final part (with decoration applied) would be something like 12345-1100, 12345-1200, 12345-1300, etc. Any time you saw the 12345 base number, you knew what part was being used.

The old ERP system was on its last legs and it was decided to replace it with something modern. At some point it was decided that the new system's auto generated record ID number would be used for our part number. This took away the possibility of using dash numbers. So now our new widget part number is 8761306; color variations are something like 8761330, 8761382, 8761401 and decorated parts are 8761332, 8761387, 8761402. I'd like to use a separate drawing number to collect and document the variations. Currently, engineering does not make a new drawing for each color variation and there is no quick way in the new system to tell if 2 different part numbers are simply variations of the same part.

Is a separate drawing number a magic bullet in our case? No. I'm sure it will cause other issues (probably with purchasing), but it would go a long way to improving our documentation.

I'm open to other ideas for improving our current system. Engineering has made a case to go back to dash numbers, but the powers that be have decided against it. So, no going back now. Progress!

 

[cowski]

IME nonstandard practices like this come about bc a manager who has always been at their tiny company thinks its a good idea, and is simply ignorant of standard practice elsewhere.

The thread linked in the OP lists a couple of books for further study. I picked them both up and "Bills of Material for a Lean Enterprise" by Dave Garwood makes a very good case for separate part and drawing numbers. It might not be the usual practice, but it is not unheard of. Both systems have their pros and cons.

 

[CWB1]

Currently, engineering does not make a new drawing for each color variation and there is no quick way in the new system to tell if 2 different part numbers are simply variations of the same part.

Are you breaking the product structure down via process with paint as a separate part like below, or just treating paint like a attribute/feature of the base part? If you can view two trees, its usually easy to see differences/variation.

AsMolded.prt-->TrimmedPart.asm-->RedPaintedPartWPaintProcessInfo.asm
RedPaintColor.prt-------------------------------^

I have seen instances where companies used faux-assembly prints outside of their products' structures to help track individual details, a reference print might show 25 color.prt's as an assembly so they could visually see everything for cost-tracking/reduction purposes. I have also heard arguments that p/ns should somehow explain/define the part, but never a good one. If you'd like to quickly/easily see unpainted vs painted p/ns tho, its fairly common to have an unpainted p/n molded/cast into the part and the final painted p/n on a sticker. Using two methods makes it obvious which applies as the sticker obviously is physically on top of paint.

Thanks for the book recommendation, I will dig into it and followup.

Edit: Had to rotate my tree sideways bc the site's "creative" interpretation of my pyramid, apologies if its unclear.

 

[dik]

I had a project once where the notice of change, and the change order used different numbers... it was a nightmare keeping track. It's nice if the proposed change and the change order have the same number, particularly when there are hundreds of them...

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik