Documentation Control

[Nella95]

Not sure where to post this question - if it goes somewhere else, please tell me.

I'm a Mechanical Engineer/Applications Engineer, by degree, except I'm in charge of accumulating documents in every department.

At my company we buy several, unauthentic parts, and use them. (There's quite a few of them.) But is it general practice to number each part with a company number and associated drawing?, or could I just copy each's catalog page, turn it into a *.pdf, then link it to whatever our company no. may be? - or is the proper practice the first scenario, which requires a bunch of extra work?

 

[ctopher]

I worked at a company that does both. they take a purchased part, assign it a number, then link it to the catalog page PDF.
I prefer to use a mil-std number when possible. If there isn't a mil-std number, setup your own system to number them. Using the supplier's P/N can be a headache if they were to change it or not make them anymore.

Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)

 

[livingston]

Our company tends to make a drawing with our part number and use the manufacturer and their part number as a reference. It does tend to get a bit cumbersome in wire assemblies though.

 

[PSE]

Every company I have worked for has had it's own unique method of assigning part numbers and documenting components and product. It all goes back to how the company was originally started (or requirements from the purchasing/inventory control software), and woe be unto them who attempts to change or integrate multiple systems.

We assign all our components a unique part number. Commodity parts (Resistors, Capacitors, Hardware etc) are generally given a description (usually text) document (revision controlled). Parts that show up on assembly drawings are done up in CAD. Custom parts of course end up with their associated drawing.

I have also worked where everything going into a product had a drawing. The drawing may be text only (for something like an adhesive, paint, or lubricant). Components were always procured by print.

As for numbering schemes, I have worked with "unintelligent", semi-intelligent, and "supposedly" intelligent schemes. Unintelligent is just a number with sole association to a component. Semi-intelligent uses "families" of a prefix or suffix for the type of component. Intelligent systems can go so far as to identify the product it goes into as well as its stocking location etc. The more hierarchical the system, the less "flexible" it becomes.

Regards,

 

[EngJW]

Same here, every purchased part is given a part number, and this is mainly so that it can be entered into the computer system and purchasing and manufacturing can keep track of it. It is our practice that a part number always has a drawing associated with it, and as not many here care what is on the drawing, it is usually just an A size with text description.

In the past regimes we had people go to extremes and take a common hardware item like a screw and dimension every feature and in some cases put on the chemical composition of the steel. I will just show a picture of the part if I have it and maybe put on a few dimensions as reference. It gets tiring revising drawings everytime purchasing goes to a different supplier and the part is functionaly the same.

 

[mechengdude]

My two cents...
To your question is it general practice, you will probably get a variety of opinions. The posts so far tend to be leaning to creating a drawing.

Going a little further ASME Y14.24 Types and Applications of Engineering Drawings is probably the definitive reference of what "should be done. This document defines various types of drawings like "Procurement Control" and "Source Control" drawings.

The way we handle purchased items is that if the purchased part is completely defined by the vendor by a unique part number then there is no need for us to make a drawing. If the vendor has a part number that is "fuzzy" like you have to specify something extra on the purchase order like "we want the one thats 24volt or thats 12" long then we make our own drawing to define the part. I find this is almost always required for electronic components which always have something strange about their configuration regardless of what the vendor catalog says.

 

[JMirisola]

In my previous position, one of my duties was to reverse engineer purchased parts. Because of the nature of the business, all were assigned internal part numbers because they could be ordered separately as replacement parts by our customers. We did produce drawings for them, but they tended to be pretty generic. There'd only be enough info on them (gpm, voltage ratings, etc.) so that purchasing could use them to find comparable products for quote.


Jeff Mirisola, CSWP

http://designsmarter.typepad.com/jeffs_blog

 

[KENAT]

In future I'd put this question in

http://www.eng-tips.com/threadminder.cfm?pid=1103

or

http://www.eng-tips.com/threadminder.cfm?pid=781

Seems like most posters so far kind of work to the more stringent end, effectively creating Vendor Control Drawings (ASME Y14.2) or equivalent/similar..

Our place asigns numbers but just puts a pdf copy of the cataloge in our secure folder for most parts. We normally download a model of it when relevent or else create our own. If it's a custom part we're starting to use Source Control Drawings (ASME Y14.24).

If you do government work then you probably need to keep the drawings. Even if you don't then I still think it's the more thorough way of doing it.

So the way your company is doing it is arguably the 'proper' practice although it does seem time consuming. The good thing is it helps protect you to some extent from the vendor arbitarily changing the form etc of the part.

We encounter this problem every now and then, the latest incident a well known engineering part supplier changed the form of what they were supplying as a certain size Allen Wrench. The new size no longer worked for it's application with us, the long arm is no longer long enough to reach the adjustment screw on the item it's supplied in the tool kit for.

KENAT, probably the least qualified checker you'll ever meet...

 

[ctopher]

I would not make a dwg of the purchased part, unless you are modifying it. Otherwise, just call out the assigned part number.

Chris
SolidWorks 07 4.0/PDMWorks 07
AutoCAD 06
ctopher's home (updated 04-21-07)