What should appear on a drawing parts list? 1

[LONDONDERRY]

Okay I have another debate with the same manufacturing engineer. Originally on an assenbly drawing I had the ITEM, QTY, PART NUMBER, and DESCRIPTION columns on a assembly drawing.
Our manufacturing engineer created so called "BOM's" for himself, that had the P/N, REV, PART NAME, UNIT, QTY columns. Though I disagree with his choice of columns, I left it alone instead of getting into a fiery debate with him. Six months later we needed to place an order for more parts, but because neither his BOM's or my drawing list the material and vendor, it took me twice as long to order parts, because I had to review all my file to see where I order standard components from. This time I revised the assembly drawing and added the MATERIAL and VENDOR COLUMNS, to streamline, if additional assemblies needed to be order.
Needless to say the manufacturing engineer, said VENDOR AND MATERIAL colums don't belong on a assembly drawing! I looked up the ANSI standards, and they list them as optional columns. However, he still wants to have them removed, for reasons unknown. SO if I remove them, and someone else is going to purchase parts, there going to have a hell of a time knowing where to buy them from. What's everyones opinion on this?

 

[KENAT]

The way I've seen it done is to have a cage code column.

Cage code gives you full manufacturers details.

You put the manufacturers part number in as part of the description.

I'm inclined to err on the side of not liking seeing vendor & material columns but if the ANSI says it's ok who am I to argue.

We're having a similar dilemma but our Manf Eng want to see Vendow and part number. We haven't finalized how we'll do this.

Is the information of vendor/pn not in your MRP system or don't you have one?

 

[Heckler]

ITEM NO. QTY, PART NUMBER, DESCRIPTION & LOCATION on the assembly drawing. I would leave the vendor name of the assembly drawing but that information should be somewhere in MRP.

Best Regards,

Heckler
Sr. Mechanical Engineer
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Never argue with an idiot. They'll bring you down to their level and beat you with experience every time.

 

[btrueblood]

I usually list the vendor & their part number when it's a purchased part; our mfg. group knows that they are allowed to purchase equivalents.

 

[LONDONDERRY]

The problem is we don't have any type of MRP system at all. The current tools used are Autodesk Inventor series with the vault. The only reason I list the vendor and material columns is because its not listed anywhere else.

 

[looslib]

Get the engineering manager to sign off on the drawings the way you have them. They convey the complete description of the parts and where to purchase them.
Tell the manufacturing engineer that these are engineering controlled drawings and if he wants to agrue, see your boss who has approved of the format.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli
Sr IS Technologist
L-3 Communications

 

[ewh]

We have a MATL column that is seldom used, but is there for this type of situation. If it is a vendor part, a flag note goes into the MATL space, and the vendor information is listed in the notes. I prefer using CAGE codes, but have so far lost that battle.

 

[drawoh]

LONDONDERRY,

If you are going to put manufacturer's part numbers on your parts lists, you are going to have to identify the manfacturer, somehow.

The manufacturing engineer's determination to have the revision number on the parts list may indicate that he is a procedural twit, or it may show a lack of trust in your design/drafting office.

I am puzzled about your material column, but I do not understand your process. If the part is off-the-shelt, your order it from the vendor or manufacturer. If the part is described by a drawing, you pull the drawing out and work out what to do with it. Fabrication drawings should call up material. Adding this information to the parts list means you have it in two places, which usually is bad practise.

Our manufacturing engineer wants to see parts lists that identify everything with our company part numbers. This actually can be made to work, if we generate specification controls for each and every off-the-shelf part. The company part number would point to a document which tells us what the part is. We have MRP. We have not done this.

I have seen parts lists which used in-house stock codes to identify everything. The document explaining the stock codes was than locked up where nobody could get at it. There was much cursing by the engineers.

JHG

 

[ewh]

I agree with drawoh about the MATL column. It is on our format to allow for multi-detail tooling drawings, where each part in the assembly isn't necessarily detailed separately.

 

[LONDONDERRY]

ITEM QTY PART NUMBER DESCRIPTION MATERIAL VENDOR
1 1 4000272 MIRROR
2 1 4000269 MIRROR GASKET
3 1 4000332 MIRROR COVER
4 2 4000624 SPRING ANCHOR
5 1 94045A515 CROSSED RECESSED
SHOULDER SCREW 18-8 S.S MCMASTER-CARR


6 1 E0240-031-0750S EXTENSION SPRING S.S ASSOC.SPRING INC.

This is a crude cut and paste of a parts list of one of my drawings. As you can see line items 1 thru 4 are detail drawings, so no information is needed on material (listed on detail drawings) or vendor columes. On line item 5 and 6 are the purchases parts, which the material and vendor colums are needed, mostly the vendor column is needed.

See the manufacturing eng doesn't want to show the vendor or material column. So if someone wants to purchase items from McMaster-Carr or Associated spring, as I have listed, and there's not a vendor column listed on the assembly drawing and the manufacturing engineer doesn't list it on there BOM's the job can't get done.

Its reasons like this people wounder why I act like I do...

 

[ewh]

I have seldom included vendor info (other than the CAGE code) in the BOM, but have listed it in the notes, flagging the item in the BOM. You could do the same with material (it is difficult to get all of the pertinent matl info in a small BOM space). Could this be a way around the manufacturing engineer's objection?

 

[KENAT]

ewh,

I like your way of doing it in the notes. I don't think the way we do drawing notes in our CAD system would support it very well though, we'd have to cut and paste or something, which is why we're considering adding columns to the parts list even though I don't like the idea.

There seems to be an emphasis here on only entering the data once, ie in the Model and referring to that one source elsewhere, this is supported more easily by the parts list.


Londonderry, do you have similar constraints?

 

[LONDONDERRY]

I'm reading about cage codes. I'v never used them before. the book I'm reading says I need refer to Handbook h4-1 and H4-2

Keep im mind its only me and another mechanical engineer, whos pretty cool. We lack alot of the support structure you typically find in mid- large companies. For examples, the two of us are designer, drafter, purchaser, and assembler (prototype only), and some times machinist ( when parts are goofed up)

 

[ewh]

Then you definitely have your work cut out for you. Good luck!

As far as CAGE codes are concerned, I'm not sure that they are required for every manufacturer, only those that do or plan to do business which is involved in any way with gov't procurement.

 

[KENAT]

Fortunately for you the people in charge of Cage Codes thought of this.

http://www.bpn.gov/bincs/begin_search.asp

This website allows you to search for cage codes etc, it's not perfect as sometimes a company has more than one cage code due to mergers etc and it's difficult to work out which to use but it's pretty usefull.

Also if a supplier has a cage code they'll probably know it and let you have it.

 

[KENAT]

ewh makes a good point. Cage codes are primarily for companies that want to sell to the govt.

That said a lot of companies do have them, I don't think I've found one yet that doesn't (not to imply there aren't many that don't). The likes of Lee Springs and other catalogues like McMasterCarr tend to have them.

For any that don't you could add notes like ewh originally suggested, at least it will keep the number of notes to a minimum.

 

[swertel]

And not all suppliers have CAGE codes, so you will need to deal with those vendors who don't somewhere on your drawing.

Our parts lists contain
QTY | FIND NO. | P/N | DESCRIPTION | MATERIAL OR SPEC

We use a matrix for each configuration number so the quantity will be for each dash number, thus it's on the left. For assembly drawings, the find number is obvious (same as item number but I think the ASME spec recently changed it to "find no."). The part number is either our internal part number or the COTS number. The description is obvious. For assembly drawings, the material or spec column is used only for those COTS items. For part detail drawings, the find number gets an 'X' and the material or spec calls out the entire detail and optional materials, i.e. 7075-T6 Aluminum Alloy IAW ASTM B221 or 7075-T651 Aluminum Alloy IAW SAE AMS QQ-A-200/11.

Finish is called out in a flag note:
Heat treat IAW SAE AMS 2770
Finish 7.2.2 IAW MIL-STD-171, color brown 30045 to 30140 IAW FED-STD-595.

--Scott

For some pleasure reading, try FAQ731-376

 

[btrueblood]

Hmm. I feel your pain, londonderry. I document my assemblies just like you do, and base my parts list on how I put the prototype together. I should have noted, though, that I usually list the mfg. and their part number as a "reference", by enclosing it in brackets (), thus notifying mfg. that they can substitute an equivalent (e.g. any old stainless fastener will do.) In other instances, we have source control drawings that call out a specific vendor who is qualified to produce the part; here, only our drawing/part number gets listed, which tells mfg. to go look up our drawing; the specific part drawing controls who/what/where etc. for the vendor part. Perhaps you could spell out with a note on all your asy drawings that vendor info. is provided for reference, and substitutions are allowed unless otherwise specified, would that quiet your mfg person down?

 

[LONDONDERRY]

KNAT-
Thanks for the link on CAGE codes, I passed this off to some people in our department.

We don't have the constraints as some larger companies, where more or less a startup biotech company, with little quality polices and the ones in place are not enforced much. So our design and drafting standards can fit to suit our needs so long as they stay within ANSI or ISO format.
One of the biggest problems, is I'm dealing with software engineers who don't have drafting experience or little or no experience with ANSI drafting standards. Its daily battle sometimes...
Some day I'll mention how they archieve drawings, you wouldn't believe me if I told you.
here check us out

http://www.srubiosystems.com

cheers.

 

[LONDONDERRY]

btrueblood -
I have used source controlled drawings in the past for the reasons I you mentioned. On the issue of vendor and material columns appearing on assembly drawing, I'm sticking to my guns. If the manufacturinf engineer wants them removed, then he better start learning drafting and Autodesk Inventor, or he'll be duing the purchasing on this project from now on.