Bill Of Material Standard for Drawings
Bill Of Material Standard for Drawings
(OP)
Lets try this thread I started a different way by breaking it down better. Forget about ANSI and ASME standards for a min. How many engineers if making a drawing of a part with 2 weldstuds, or pemnuts, ect...some type of permanent hardware to the part don't use a bill of material on their drawing, you just leader line out a note on what needs to be installed or welded? I understand you use a bill of material if you MAKE it in house, but we don't. We don't stock pemnuts,weldstuds, weldnuts, ect...So my standard would read,"A bill of matieral is only needed on a print, if it is a weldment,a physical assembly we build, or it's an assemlby that can be dismanttled easily into loose items." Thoughts?
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"





RE: Bill Of Material Standard for Drawings
We used to have drawings of inseparable assy's and the like with just callouts to the parts. Things would get missed or there'd be questions.
Most of our inseperable assy work is also done externally like you and this system seems more robust. We don't stock the pem studs etc.
Then again, we took the decision to follow ASME standards some time ago, so forgetting them isn't really an option.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
"Art without engineering is dreaming; Engineering without art is calculating."
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RE: Bill Of Material Standard for Drawings
In your example, why are weldments different than an assembly using PEM nuts? Both are inseparable, aren't they?
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
"Art without engineering is dreaming; Engineering without art is calculating."
Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of these Forums?
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
???
Components in weldments can easily be identified with dash numbers. They should be identified in some manner, regardless.
Other items such as hardware usually have a vendor number if nothing else.
Numbers are cheap, and I find your reasoning for not creating them somewhat baffling.
If you plan on remaining a very small company that can reliably use tribal knowledge indefinitely, then no problem. Otherwise, it is time to smell the coffee.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
"Art without engineering is dreaming; Engineering without art is calculating."
Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of these Forums?
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
I make a distinction between a parts list which we use to order our parts, and a material list, which we apply to fabrication drawings that are sent out to a vendor. The vendor orders the pieces on the material list and attaches them to whatever they are fabricating. We order and stock the stuff on the parts list.
Both parts list and material list are implented using SolidWorks' BOM feature.
The most important thing you can do on your parts list is make sure your data is set up in the same format as your purchasing requisitions and your MRP/ERP database. You should be able to copy and paste out of your parts list and onto your requisition form. Information should be typed once, only.
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
It's surprising how many descriptions used are actually incomplete or open to misinterpretation. Referring to a specific vendor/manufacturer & part number significantly reduces this likelihood.
We're actually gradually updating a lot of our assy drawings to add more 'manufacturer part numbers' for even fairly standard fasteners, since descriptions alone are sometimes unclear to our offshore vendors.
We don't typically create a BOM in SAP for our inseparable assemblies, we treat them as we would simple parts. However, the drawings have a parts list with the pem studs or whatever as well as the basic sheet metal or machined part. Due to limitations of our SAP implementation, our CAD package and our established doc control system, we fudge a few aspects but it seems to work.
When outsourcing (be it domestic or foreign) it's even more important that the drawing is unambiguous and easily understood, following established standards really helps with this.
I've never seen a really good Japanese drawing, they've always been a bit lacking. Now clearly this hasn't held them back much, but unless you're also copying whatever else they do that makes it work for them, I'd be careful.
Also, I learnt, and occasionally have to relearn, just because I've done something a certain way before and apparently got away with it, doesn't necessarily mean it was the right way.
MadMango, if the OP is creating the fully detailed drawings, and just outsourcing the actual manufacture, then a Source Control probably isn't appropriate. We outsource most of the inseparable assy type work and some assembly work, we experimented with expanded use of Source Control drawings but it didn't' work out. Conventional assy drawings do seem to work, you just need to make sure all items are adequately identified that anyone can go buy them without access to your ERP system.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Bill Of Material Standard for Drawings
I'm not sure what you are asking for, then. As they say, opinions are like a******s, every body has one.
Drawing standards are just that, standards. If we are to forget about what they say, then you can pretty much do whatever you want.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
On your sample for instance, you don't really fully define the pem nuts. From memory aren't there different material options, even maybe lengths etc. Obviously you don't have to have a parts list to add the part number, but to me it's a tidier way to do it than with the callouts.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
You have every right to continue to define parts as you do, just don't be suprised if others may find them difficult to interpret.
Your example drawing seems to have been created by someone who is somewhat familiar with the standards, but can't be bothered with having to actually follow them. Again, this is fine if it meets your needs. Just don't expect everyone to agree with arbitrary rules followed only for your own convenience.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
As far as line types and weights, they are still relevant to ease of drawing interpretation.
But then again, you don't seem to have to worry about that.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: Bill Of Material Standard for Drawings
For simple frame weldments, I'd use a cutlist. Again, a BOM is redundant to the cutlist.
In fact, I've not found much value in using a BOM for most inseparable assembly scenarios (95% of the time).
BOM's in my company's system are controlled by our PLM anyway, so they do not appear on the drawing in the first place.
This is just what I've experienced. Your experience may vary. :)
Matt Lorono
Lorono's SolidWorks Resources & SolidWorks Legion
&
RE: Bill Of Material Standard for Drawings
For other mechanical assy's, I either add the BOM on the dwg, or make it a separate document.
This depends on company policies, contracts, and standards.
Chris
SolidWorks 09 SP4.1
ctopher's home
SolidWorks Legion
RE: Bill Of Material Standard for Drawings
Jason Schultz
Mechanical Engineer
Yaskawa Electric America
"It's got to be 5pm somewhere!"
RE: Bill Of Material Standard for Drawings
Per ASME Y14.34 ASSOCIATED LISTS, "Parts lists shall be prepared for each assembly level drawing and may be prepared for other level drawings."
I think they are correct because of the standard based definition of "assembly". Per ASME Y14.100 ENGINEERING DRAWING PRACTICES, "assembly: a number of parts, or subassemblies, or combination thereof, that are joined together to perform a specific function and subject to disassembly without degradation of any of the parts.
Picking and choosing what is correct only because it already agrees with your opinion can be dangerous. It is always good to have a sound foundation on which to base your drawing practices. But I forgot, standards don't have any bearing on your issue.
In my own experience, working for mid-size to large companies, parts lists were a requirement for both separable and inseparable assemblies. This was to do more with procurement than anything, and was not difficult to provide. Different situations require different solutions.
It does raise questions though when standards are ignored because they are inconvenient. What is the point in even writing a "standard" if that is the case?
"Good to know you got shoes to wear when you find the floor." - Robert Hunter