Product Numbers, Drawing Numbers and Part Numbers oh my! 2

[Korichnevijgigant]

I work for a small company and in the past most of the engineering work was outsourced to supplement my teams "capacity"

as such we had a consultant early on laying the foundation, part of his influence on the board is part numbers.

He belongs to the intelligent part numbering community and has set up a lot of really bad numbering systems in my opinion both in older documents and in our MRP system.

We are currently in design of a huge new project and I am trying to get out in front of him before he poisons us again (the management team really trusts him)

I wanted to see what the opinions on here were regarding:

1) Drawing and Part numbers need to be separate numbers, generally in the past I would make the drawing for a part or assembly ABC123 and the parts belonging to that drawing ABC123-XX-YYYY
right now the drawings are AB123456 and the part or parts in that drawing are the same number just have a description annotation

2) product numbers live in the same part number sheet as everything that goes into the part
a screw for example is AB987654 and the product that uses the screw is AB100001
right now we are going to start getting into customization of products and I think this numbering scheme stops us cold

3) dash/suffix levels, in the past I used an assembly ABC123-00-0000 as the top level assembly in drawing ABC123, then that assembly had subassemblies in it like ABC123-01-000 and ABC123-02-000 and they had parts inside them ABC-01-001,-002.... and so on
the "intelligent" numbering system in our work instructions do not allow for this as we are limited to a single 3 digit suffix

Thoughts?
Am I crazy?
Thanks

 

[MikeHalloran]

You're not crazy, and you're not alone.

If any fields in your documents, e.g. single 3 digit suffix, are limited to just a few characters, you need to get that fixed right away.

Your IT people will probably not like that, because they are used to fixed length fields,
and changing the maximum field length is a huge hassle for them because
every function of every one of their stupid systems is a separate program,
and they have no internal documentation of how any of it works,
or is intended to work, and no record of which idiot wrote any part of it.

First place I worked after college adopted a numbering system comprising:
- four alphanumeric characters encoding decade|year|division|company
dash
- four numeric digits encoding which part corresponds to a prototype
dash
- several alphanumeric characters encoding modifications/revisions/whatever
The original prototype was a Model T.
Since then, their products have become more complex, and they have had to add digits to all fields. Their original smart numbering system became overwhelmed by entropy pretty quickly.

One place I worked sold Spanish motorcycles, which used a similar part numbering system.
Parts were stored alphabetically, by the second field, not the first. Took a while to get used to that.

One place I worked had several numbering systems, because it was easier to add an entire new field than to make existing fields longer. ... and their Marketing department had another entire set of part numbers because the IT department was completely uncooperative and the engineering department was so confused.

Last place I worked was an engine dealer who also manufactured stuff.
Their part numbers for purchased items were the same as the actual manufacturer's
part numbers, but modified at first entry time (by a low wage clerk with no product knowledge)
because their IT systems couldn't accept all characters in all fields.
They had multiple inventories of the same part under different numbers.
Their IT system could find a part by searching on a description,
then could not accept the found part number when entered directly.

IN SUMMARY, part numbers are a huge mess, globally,
only partly because of decisions made by, e.g., IBM, when punchcards were involved and memory was expensive,
and partly because early influencers were arrogant enough to think that a smart numbering system could work indefinitely and be useful to all interested parties.


Units of measure deserve a rant all their own, so I won't get started on that here.






Mike Halloran
Pembroke Pines, FL, USA

 

[Korichnevijgigant]

Glad I am not the only one. Fortunately I am in charge of the PLM system and the IT person who work on it, so it gives me some horsepower, BUT overcoming management perception....

Oh I know what you mean about Unit of measures... I took away our purchasing departments ability to add them, because I started seeing stuff like "10 FOOT LENGTH" and "1 Sheet"

 

[MikeHalloran]

Oh, damn, you had to open that can of worms, too.

For a PLM/MRP/whatever system to work, the math has to work, too.

Including for stuff like Loctite, where the amount added to a single fastener would be several microliters, but it comes in 3oz bottles, or at a better price, 12oz bottles.
Plus, for adhesives and stuff, you have to also manage expiration dates,
which typically requires an in-house labelmaker and a record of purchase date, etc.
So you might logically add fields for:
unit of use, e.g. ul
quantity of use, e.g. 3
unit of issue, e.g. bottle
size of unit of issue, e.g. 3 oz
unit of purchase, e.g. case/12
purchase date
lifetime
expiration date

... and the complexity just keeps increasing.

And Top Management (pejorative) never wants to deal with complexity or details.





Mike Halloran
Pembroke Pines, FL, USA

 

[drawoh]

MikeHalloran,

I am having a slow day here.

I am looking at a database that has a quantity column in which I can select units. Normally, this is a count. If I need string, wire or grommet strip, I can select length units, and I assume someone will put the required length of material into the assembly kit. The system seems workable to me.

Is there any reason why they cannot kit a 3oz bottle of thread-locker, and then put it back in stock once the assembly is done? It is then ready to be kitted again. At some point, the assembly worker or the stock clerk will observe that the bottle is empty and will not return it to stock. Unless you are monitoring an expensive or nasty liquid, I don't see a need for excessive control.

--
JHG

 

[Korichnevijgigant]

Hi Drawoh

In the past I have put the thread locker on the router/traveler and the manufacturing floor just kanbans those type of adhesives/chemicals

OR you could calculate the worst case material condition for the bolt and nut and calculate the resulting volume in the threaded region and assume some overflow to add to the BOM... just joking

 

[MikeHalloran]

you could calculate the worst case material condition for the bolt and nut and calculate the resulting volume in the threaded region and assume some overflow to add to the BOM... just joking

I was not joking about putting X microliters of Loctite on a BOM; I have done it.

It would be more critical to do so, for material planning, if it were a long lead item.
Since it's usually available locally, using a kanban can work as well.
Outfits like Fastbolt USA will be happy to help you with kanbans comprising internal local stock of stuff like Loctite and nuts and bolts.

... But then it gets complicated again. I wouldn't return a partly used bottle of Loctite to stock, just on general principles, and because it expires or could be contaminated.


<tangent>

I first ran into the problem of small quantities of use fifty-ish years ago, when I specified an o-ring in an assembly as a friction damper, assuming that the assembler would lubricate it with _something_ at assembly.

They didn't, and the assembly was too tight both to assemble and to operate, when they put it in dry.

It was a union shop, and the crew, rightly, wouldn't apply anything that didn't appear on the BOM.

So I got to originate and push through an ECN to correct my mistake of omission.

</tangent>

Hey, I said it was a can of worms. ;-)



Mike Halloran
Pembroke Pines, FL, USA

 

[truckandbus]

Hard to keep everybody happy. Had one service manager that wanted every subcomponent documented with correct quantity. So when we released a wheel sander I asked if he was okay with a drawing of a piece of grit, quantity 750,323

 

[drawoh]

truckandbus,

On a wheel sander, the grit ought to be rather important. If I am applying the grit, I would want a drawing or a specification control. I would specify the mass of the grit, or the volume. Whose job was it to count the pieces of grit?

--
JHG

 

[truckandbus]

@drawoh - the wheel sander in this case is a box with an auger in it that deposits grit ahead of the drive wheels of a bus as it comes to a stop on a snowy or ice covered road so that when the bus starts moving again the wheels have some traction.

 

[truckandbus]

I had another situation where 'swipe cards' were sold to us in bulk - 100 cards per box, and each box was $100

The cards were consumed 1 per vehicle built per the BoM call out. The boxes were inventoried based on the piece count so a $100 box of parts was logged as $10,000 worth of inventory

 

[3DDave]

That reminds me of a plaque in a grocery store where the $/item was around $600 for AA cells. Turns out the 'item' unit was a case, and it wasn't Sam's Club.

Everyone has my sympathy for any numbering 'system' that has either limited fields or some amount of intelligence. The worst are the people who want the numbers to be orderly and provide some magic transference of knowledge, like that if the last two digits are both odd, that it's a weldment and other such nonsense.

My favorite Qty problem - A guy I worked with for a while mentioned that he worked at a home tools company and had developed a process, including testing, for retaining the rubber grips on rake handles. It was one drop of cyanoacrylate into the rubber grip and then slip it on. He calculated the amount required for the months long production run, about a quart, which was several hundred dollars. He gets a frantic blame call that they are out of adhesive after the first week. It turned out one assembler was unconvinced that one drop was enough, so he just poured some in to make sure. Since there was an interference fit, most of the adhesive just squeezed out and ran down the handles, making a big mess. They had used 10,000 rake's worth of adhesive on a few hundred now unsaleable rakes.

 

[drawoh]

truckandbus,

I was in a couple of situations where we bought a COTS assembly, took it apart, modified some of the pieces, and then re-assembled it. My solution was to generate a specification control for the assembly, and then assign tabulated numbers to each part of the assembly. I called up the tabulated part numbers on my BOMs. The tabulated numbers pointed back to the specification control, which called up the manufacturer and part number to be ordered. When the unit came in, production could take it apart and store everything by the tabulated numbers.

--
JHG

 

[drawoh]

truckandbus,

Tabulation works on your cards too. My specification control document 123-456 calls up the box of 100[&nbsp;]cards. The specification control identifies the part number 123-456-01, which is one card. When the parts bin is empty, production orders another box.

--
JHG

 

[Korichnevijgigant]

drawoh,

I have done the same with modified COTS parts, or modified custom parts that are stock items

But I have seen this go wrong when crappy MRP implementation (consultants are the worst...) didnt connect correctly to the COTS parts and its safety stock so we would use up the items in stock then when another production line picked those items the stock room would freak out...