New company, no rules! Yet......

I am curious as to learn different methods for creating a system for generating as well as managing part numbers in an engineering group. As with any system there are pluses and minuses that go along with it. Lets hear what you do, how would you do it differently, etc.

This is what we are working on:

Part numbers consist of (2) sets of numbers. The first set is comprised of a single digit identifying its Class followed by a two digit number identifying its family. The second set is simply a five digit number ordered sequentially. (Example: 120-12345 would be an electrical schematic for an assembly)
Class	Family	Description
1	00	Assembly/Sub Assembly
	10	Kits/Spares
	20	Electric Schematic
	30	Pneumatic/Hydraulic Schem
2	00	Mfg Parts
3	00	Hydraulic/Pneumatic COTS
4	00	Electrical COTS
5	00	Hardware Imperial COTS
6	00	Hardware Metric COTS
7	00	Power Transmission COTS
8	00
9	00	Misc (DON’T BE LAZY! USE AS LAST RESORT!!!)

 

Your numbering system is very similar to one I put together for a customer. You'll have people telling you to abandon the intelligent numbering system and just go with a sequential number. I'm not sold on that opinion, but I understand their argument. Your "Misc" category will catch lots of random parts, your "Sub Assembly" may get a few "Kits" in it, your "Electrical" will probably pick up a few "Power Transmission" parts, etc.

But I like to look at a number and have some clue what to expect. This is partly due to my filenaming convention for SolidWorks files. I name them by the part number and rev. So if I'm looking for a particular assembly, I know to look in the files starting with "1".

The one thing I do in addition to this is I tag a "Revision" letter on the end. My revisions exclude letters "I & O". For example: 120-12345A

 

Our part numbering system is slightly different. We number parts by the stage of production they are in. For example a part in it's raw form would be a 50000 number, then as it goes through the processes and becomes a retail part it gets down to a 10000 number, so all 1000 numbered parts are ready for sale. We like to try and keep the last 3 numbers of the parts the same through the process, so a part numbered 52222 would be the same as 12222 but at it's final retail stage.

 

You may consider to categorise drawings and actual parts. For example an assembly drawing can have the first set of numbers different to the actual assembly (physical part) itself. The advantage is that you can have a single drawing controlling multiple variants of the part. An example of this will be a single drawing for all the metric screws that you purchase, all you need is a single drawing with a table in it which defines all the screw sizes and length.

You may also consider categorising by having a suffix number. For examples, use can use suffixes for different finishes if the same part or the likes.

 

Great topic. There are two types of part/ product numbers: "talking numbers" where you can gain some information about the product from the number and "non talking numbers" where you can't.

A part number is a bit like a lorry - it's purpose is to carry product information (as a "pay-load"). The increasing importance of information means that part numbers need to carry more information.

Talking numbers (like the Brisch / NATO stock number system etc) need to be longer to enable them to carry the information required - consequently there is a trend to use non talking numbers.

A further consideration is where the product information needs to be carried. From design to production, inventory and maintenance systems. There needs to be a process to seamlessly communicate the number (and associated information) around the business.

Finally, products have an irritating habit of needing to be changed (design revision) and there needs to be a clear process for allocating a new number in the light of any design change. I undertook an industry survey earlier this year. The four largest sectors represented by responders were, rail (24%), automotive (22%), aerospace defence (18%) and industrial equipment (15%). Just under 78% of respondents said that the rules for allocating new configuration information (like the "fit, form, function" test) were not clear.

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Same discussion I've seen in every company I've ever worked for... and every company does it different, for different reasons. Unless you're working on military or other government contracts, then they may specify what you must use.

Tied in with how to structure numbers is what, if any, document management software. Also there is the requirement to insure all numbers are unique, while not making it too tedious to "get" a new number.

Where I work now, our software creates a "card" with a unique ID number (could be any length, ours are six digits). For many things, that ID number may become the drawing, just the six digits, no "intelligence" to the number. For a larger machine project, we create the first "card" and use the unique six digit number as the base, with a dash number chosen by the engineer. Getting a "block" of numbers like this makes it a lot easier for the engineer, so you don't have to enter the number in the system or book immediately when you create a drawing as nobody else will be using that prefix. There is some but not rigid guidelines: The overall machine assembly is -100, (e.g. 037257-100), -200 or -300 might be a major subassembly, -200 might consist of smaller subassemblies -220, -230, etc., while -220 might include components -221, -222, etc. Numbers lower than 100 might be sketches, layouts, or installation drawings. Note that not all numbers from -001 to -999 will be used, and the gaps may be filled in later. This makes it easy to identify parts, glance at drawing 020566-346 and you know it's part of the "-340" assembly of the 020566 machine.

We also add additional letters or numbers where appropriate; a matched pair of mirrored parts might be 104372-206-R and 104372-206-L, or 059792-109-6.250 for a "cut to length" part cut to 6.250 inches long.

When I worked for the military some years ago, we used a similar system except that the dash was replaced by the drawing sheet size, i.e. 123456D102 meant a D size drawing, so you knew what drawer to find it in. This is less useful today with the CAD files more important than the paper prints.

Don't rule out alpha characters for part of the part number; 26 letters gives you more to work with than 10 digits.

Many, but not all, organizations consider the revision letter to be a part of the drawing/part number.

 

What standards (ISO etc) do people usually use to guide practice in this area? As a starter for 10 how about: PLCS (ISO 10303), JT 9.5 (now ISO 14306), ISO 8000 etc. It's a minefield I know but any thoughts would be great.

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This is probably one those discussions that will always circulate through engineering chat-boards. I've worked on both sides of the fence on this subject (Documentation and R&D). While I don't agree with some of my peers with regards to smart P/N's ... they have their place and I think they definitely add value to the system. However, I also don't like to use or see "overly smart" P/N schemes either.I can say with a fair amount of experience (using SolidWorks) that you should NOT include the revision in a P/N. You're asking for trouble ... BIG trouble. My recommendation to you (since this is a new company) is that you should invest in a Product Data Management (PDM) software. This will eliminate the need to include the revision in any P/N scheme.

 

I wouldn't suggest using the revision in the part number as stored in CAD. If you change the revision (at least in SolidWorks) all your drawings and other references will disappear. This will create a lot of work. I would only suggest using revisions as part of the file number on the drawings files.

 

My take on part numbers.

In my opinion sequential numbering is best.
You can distinguish between specific sequential numbering conventions for each specific project.
Then if you have standard parts you can have all of those part numbers start with a ST... for example.
Your part number should also be the same as your drawing number.
So if you need to call up a drawing, be it a single part or assembly drawing you just need the part number and vice versa.
It helps the entire process from design to commissioning of small jobs to Mega projects!
Just my 10c worth.