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Resources for drawing number system from scratch

Resources for drawing number system from scratch

Resources for drawing number system from scratch

I have a very large R&D project coming up at work and our current drawing system and practices are not ideal for a project that is being started from scratch. There will be approximately 10-15 main project components with many sub-assemblies and hundreds of parts stemming from those. There will be a lot of assembly and part drawings along with electrical, plumbing, installation, etc. drawings. Unfortunately, the company is pretty old school and documentation is not its strong suit, so I don't have much guidance.

I've never started a large project from the incipient stages, so I'm not really too sure where to begin with planning the drawing system around this. There has to be some thought that goes into this so the system doesn't crash or come to a halt six months from now.

One example of an issue I'm facing right now is assigning a drawing number to a very preliminary system schematic that will be going out to a regulator body so they can begin their initial certification and documentation process. Like I said, this drawing is very preliminary, so it's bound to change. A majority of the system design has not been started yet or gotten assigned a drawing number set. I'm worried about the drawing number for this document not fitting in when the rest of the system is designed and I'm not really sure how to plan that far ahead when there are still very many unknowns about this design and R&D hasn't really been started on this subsystem.

Would anyone be able to help me out with some resources on drawing management and drawing numbering systems, specifically when it comes to R&D projects where several parts and systems may be developed before a final version is released? How do you handle documenting and assigning drawing numbers to concept designs and then taking them to production or final release? TIA

RE: Resources for drawing number system from scratch

Typically drawing numbers are a couple sequences of numbers with one engineering discipline getting a sequential group of numbers.

Examples sequences that come to mind are
(1026-C-001) Area 1026 - Discipline Civil- number in sequence is 1, the area would have an accompanying list for the site
(1234-2001) Project 1234 - 2000 represents mechanical and the 1 is the sequence

RE: Resources for drawing number system from scratch

I actually really like that way of part numbering and it sure seems like it would beat our current system. It would be easier to assign part numbers and tell what the drawing is based on the sequence number. This is actually a great starting point!

I was thinking of using the following:
10000 Installation
20000 Assembly
30000 Part
40000 Plumbing
50000 Electrical
60000 Supplementary
90000 Outside Vendor/Quote

One question I can think of right off the bat is how would I handle two different sequences for the same part. For example, we have face plates that are made by an outside vendor. These may have two sets of drawings. An internal drawing that calls out equipment notes and features that are added after we get the face plate from the vendor. The vendor gets a separate drawing for manufacture and quote.

Let's say this part is number 10 in the part sequence, but it is the first drawing to go out for quote, does it start from 1 or should we also make it a 10 and keep track of this using a drawing list?

XXX-30010 - Internal Face Plate Drawing
XXX-90010 - Face Plate Vendor Manufacture/Quote or XXX-90001

RE: Resources for drawing number system from scratch

We use a simple number format of the form ppnnnnn where the first two digits indicate whether the item is a non-tabulated COTS (commercial off the shelf) part, a tabulated COTS pat (e.g., screws of different lengths), or a part for a specific client (could be a project or a subsystem in your case):

  • 10nnnnn - COTS pat; nnnnn is incremented
  • 11nnnvv - tabulated COTS part; nnn is incremented; vv varies with the variable parameter. We only allow one variable parameter (e.g., length) for a given base number, so you would need a different base number for each thread size and material combination.
  • 20nnnnn - Custom parts for client or project 10020.
  • 21nnnnn - Custom pats for client or project 10021.
We don't have any more intelligence than that built into our part numbers. Instead, we have a category field which we can use to specify the type (assembly, fab part, reference document, specific type of purchased component). We maintain a spreadsheet with category structure. That category spreadsheet also specifies the naming convention for a given category as well as two parameters (e.g., thread size and length) that we like to record for each COTS part. Even if you are using Google Sheets for you part database, it provides remarkably powerful filtering capabilities for showing only parts that match a specific category; description; parameter; vendor name or number; or combination of those factors.

The category ID is a pseudo-hierarchal number so that you can filter broadly or narrowly, for example, filtering on "2002" will show all radial bearings; "20022" will show only duplex bearings; and "200221" will show only back-to-back duplex bearings. We evolved this when we were using Parts&Vendors. We put some planning into the overall organization and only refined categories over time as needed. It's much easier to do that than to try to reverse engineer things later on, or to try to figure out every possibility from the start.

I sometimes consider adding an 'A' prefix to assemblies since it helps when you do need to manually scan through a list or folder.

- Rob Campbell, PE
[link Practical Precision]practicalprecision.com[/link]: Precision and optomechanical design resources and services.

RE: Resources for drawing number system from scratch

I would strongly suggest not complicating the p/n by placing any sort of "logic" in it. Its a "number" (alpha-numeric), that's literally all it needs to be. Adding "logic" results in needlessly long p/ns. You gain absolutely nothing from this and will seriously lose between mistakes in reading/copying lengthy p/ns, increased product costs, and customers recognizing that you're very poorly organized. You will also undoubtedly piss off a major portion of your organization once the application of your original logic starts to fail on new products. Most importantly, doing so makes autogenerating p/ns and automating management of product structure via PLM an absolute nightmare, usually leading to someone having to manually assign p/ns for every assembly level of every product - needless manual labor which almost always leads to shortcuts causing further lack of organization.

As to managing release status, most companies today manage this via PLM/PDM. Antiquated companies manage this by having someone "sign" the title block either physically or virtually, signifying the print's release. Until its signed that rev isn't released. I would not do so without PLM, but within PLM you can also specify release types - research only, prototype, production, etc, which allows you to iterate and approve each step of each revision's development in a formal/controlled process.

RE: Resources for drawing number system from scratch

Document Number

AA = Area Code
BB = Originator eg. [CL]ient, [CO]ntractor, Vendor (each vendor different code)
CC = Discipline Code, eg. [ME]chanical, [EL]ectrical, [PL]umbing, [AD]min, etc.
DD = Document Type Code, eg. [DR]awing, [SP]ecification, [PL]ot, [SC]hematic, MOM, etc.
EE = Sub Document Type, eg. [GA]General Assembly, [DE]tail drawing, [CA]lculation, etc.
GG = System Code, eg.
Last 4 digits
0001~0099 - some type 1
0100~0199 - some type 2
0200~0299 - some type 3

Change the format as you like and assign different codes for different categories so you can filter in different ways in whatever document management system you are using.
Prepare a single document where Codes are listed and assigned.

RE: Resources for drawing number system from scratch

In these technology times, the best part numbering system is one that is an insignificant sequential number.

Everything else can be stored as parameters or attributes within the metadata of the item for classification, searching, filtering, etc.


RE: Resources for drawing number system from scratch

Something that can take the pain out of part numbering and managing a project like this is simply a good tool, which excludes MS Excel, and that system doesn't have to come with an up front price tag of thousands of dollars or months of planning and implementation. Check out aligni.com and similar tools (e.g., openBOM.com, which I'm less familiar with). Aligni can't manage CAD, but it can manage just about everything else, including change history if you want it to.

- Rob Campbell, PE
[link Practical Precision]practicalprecision.com[/link]: Precision and optomechanical design resources and services.

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