State amount on part-drawings (??) 4

[pietje]

Can't find a proper forum for this question, so I decided to post it here...

My colleague, who orders all the pieces of art that we produce with SW, is complaining that we do not state amount-numbers on part drawings.
I tried to convince him several times that amounts should never be stated on a part drawing, only on assembly drawings. I know from practice that some engineers do it anyway, only I refuse to do it because it causes all sorts of issues. For example if the main-assembly states 7X part A, and the drawing states 7X too, don't be surprised if you end up with 49 pieces. Another example: If he wants to order 3 extra pieces I will have to rework or copy&change the part drawing only to change the amount that is stated on it. On top of all this it is possible that assembly and part drawing state different amounts due to update issues/human errors. I think an amount should be defined at one location only.
His argument is that if he orders something, the person or company that has to produce/deliver can find all information needed on the drawing, including the amount; no other documents are needed. He finds it easier for himself too ofcourse because it saves him time and effort.

My question: Are there rules (we mainly draw acc. ISO) that forbid or leave it to the engineer to state amounts on part drawings? I read through my standards-book but can't find anything on this subject.
Are there any more arguments that I or my colleague (the enemy ) can use to make a decision in this discussion?

thanx beforehand

 

[ArtL]

I agree with you, as far as amount listed on prints. I don't ever list amounts on prints. Only on assy BOM's and on the purchase order. The purchase order should be the only thing you should go by. I get paid by purchase order, not by a print.When I get a purchase order from a customer, the purchase order lists amounts for each Part in a assembly, which I then write on the prints to correspond with the purchase order.

 

[TheTick]

This is part of a broader mistake: believing that engineering drawings need to capture all information at all levels so that lazy or incompetent people don't need to use the MRP system.

 

[gwubs]

We do not put assembly quantities on part drawings. That is assembly information. Also, parts hopefully can be used in a variety of assemblies, so the quantity for ALL those assemblies would need to be listed on the part drawings. What about SUB assemblies? A nightmare in the making if you ask me. The build level of any order defines how many of which parts are required - it's that simple. I think TheTick has put his finger on it quite well.

 

[cpretty]

We had a very similar argument/discussion at a place I worked at. The outcome was no numbers on drawings, but it took a while.

2 questions asked can help sway the decision

1) If I try to order 2 or more assemblies, what number should be on a drawing?

2) If I want to order spares (just in case) or for servicing, what number should be on the drawing?

I agree with the others in that people seem to think too much should be on the drawing.

The correct place for quantities of parts is a BOM.

 

[ewh]

... or a purchase order.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[ctopher]

I agree with the others. Great comment Tick!
When it comes to engineering drawings, I see more ignorance from people working with drawings than anywhere else. A little more education on this subject will help deter bad drawing habits.

Chris
SolidWorks 09, CATIA V5
ctopher's home
SolidWorks Legion

 

[pietje]

I think it's partly up to us engineers to educate people down the line why certain things are on a drawing and why other things are not. Therefore I think cpretty's two arguments will work best when trying to persuade people not to ask for amounts on part drawings any longer...

thanx everyone

 

[Galdeen]

I agree with Tick too.

What if a part is used in 2 different assemblies?

I work in the automotive industry...what if a different model uses a different amount?

I could go on and on with reasons why this is not a good idea.

 

[CorBlimeyLimey]

I agree wholeheartedly with the above sentiments; permanently adding the part quantity in a part drawing is asking for trouble.

However, if you are forced into doing it, there are several methods listed in thread559-249517

 

[drawoh]

TheTick,

Yet another mistake is storing critical information in more than one place. The quantity goes on the parts list, only.

When it is time to update the quantity, the parts only gets updated. If each quantity is stored in three or four different places, how many of them will be located and fixed?

JHG

 

[ewh]

[q]The quantity goes on the parts list, only.[/q]
Ideally, yes. Unfortunately, many (if not most) companies rely on ERP software which may not be compatible with their CAD systems, thus having to enter this information in more than one location - the drawing parts list and the project BOM.

"Good to know you got shoes to wear when you find the floor." - [small]Robert Hunter[/small]

 

[MikeMcL]

ewh, this is why we stopped putting BOMs on drawings 30 years ago. The only true bill is the one in the ERP system. It drives purchasing, inventory and everything else. The BOM from the CAD program is almost certainly going to be incomplete.

 

[drawoh]

Ideally, yes. Unfortunately, many (if not most) companies rely on ERP software which may not be compatible with their CAD systems, thus having to enter this information in more than one location - the drawing parts list and the project BOM.

Okay, the ERP makes it two places. This is much better than three places or six places.

If you set up your ERP and your SolidWorks BOMs correctly, you should be able to copy out of Solidworks, and paste into ERP.

JHG

 

[pejaer]

After reading through this thread, I am confused what most commentators are arguing: eliminating the BOM (with qty) from all SW drawings, parts and assemblies, or part drawings only. I mean, I agree with not having qty on the part drawings, but BOMs and qtys on the ass'y drawings is my practice.

The reason for my question: I am using the BOM features in SW for all my assembly drawings, with the expectation that I actually have an ERP system in the future, ie I want SW to be the "driving system" and push the data to the ERP. I agree that updating two systems, SW and ERP, manually, would cause error.

So I would be grateful (for us slow learners ) if someone can just summarize and clarify what is meant when the contributors are saying simply "BOM", "engineerign drawings" "prints" "drawings"....they all need more context in which system you are referring, and in the case of SW, part or assy drawings.

Point 2: maybe more relevant to me, how realistic is my goal of using SW to maintain my BOM (with accurate quantities reflected by having same multiple parts in assemblies where appropriate)? Will it eventually transfer to a ERP OK?

Thanks
Paul

 

[NomLaser]

Pejaer

Not sure where ppl are going now. OT was about quantities on part drawings and not assembly drawings.

A lot of what you are wanting to do depends on what ERP system you decide to use. Made2Manage is popular around here (for what reason I have no idea, personally I don't care for it) and has the option to import SW BOM's directly from SW. I have never used it but I know that the option is available.

 

[CorBlimeyLimey]

Firstly, assume the terms, BOM and Parts List, to be interchangeable ... some people make a distinction.

The data for an ERP or MRP system has to come from somwhere. IMO, that somewhere should be from the SW assembly. Whether that data is on placed on the assy drawing or a separate sheet is immaterial; they are both printed documents. (I prefer the assy drawing). The data could also be exported directly from SW to the ERP/MRP system.