Do Find Number on a Parts List have to be sequential?

[wearules]

We have a new assembly that was made from an existing assembly but has a few less parts, specifically early in the parts list. Now similar parts on the two drawings have different find numbers making it confusing for the person comparing them. He asked me if the new assembly's parts list can have some find numbers skipped to make comparison more convenient. The only thing I could find on find numbers was in ASME Y14.100, par. D-8. This states that find numbers are "for the purpose of cross-referencing an item identified in a Parts List(PL) or table on the drawing to the location of the item in the field of the drawing, in lieu of using the PIN in the field of the drawing". It does not state anywhere that the find numbers have to be sequential. Does anyone know of an ASME standard that states find numbers shall be sequential?

 

[BrianPetersen]

Given the complete dissimilarity between (let's say) Yamaha part numbers and (let's say) Volkswagen part numbers, I'm going to say that you can do this in whichever way you see fit.

There may, of course, be an internal company standard that defines the format of part numbers. I'm sure Yamaha has one themselves, and I'm sure Volkswagen has one themselves, but they're not similar.

 

[IRstuff]

I think having the same find numbers are OK, barring objections from your drawing manual; you can, of course, leave all the find numbers and simply put N/A for the parts that are no longer relevant

TTFN (ta ta for now)
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[swertel]

They don't have to be sequential. I've seen plenty that start with 100 and increase by 10s. Then when a replacement part is used, use an '5 Find Number, and so on. Why anyone would make Find Numbers significant/intelligent is beyond me.

What is specified though is that Find Numbers are not supposed to be reused unless their is a complete REDRAW. That means you either remove the find number from the Parts List (thus not sequential) or you replace the row contents with DELETED.

--Scott
www.aerornd.com

 

[drawoh]

wearules,

The part numbers on your parts lists must be unique. You must follow design change rules to assure that your part numbers identify parts that function in their application.

The find (item?) numbers on your parts list are situational to me. On a drafting board, changing item numbers means I have to search through the paper drawings looking for references so that I can update them. It is not worth the effort and the mistakes. In SolidWorks...

[ol a]
[li]I prefer to sort my BOMs in order of assembly. I group my parts, with their fasteners, in order of assembly. When SolidWorks changes the item numbers, it updates the BOM, and it updates all the item references. You do have to watch which BOM is being referenced on a given drawing view.[/li]
[li]I like to export my BOMs to an external Excel file. It takes about a minute to assure the top row prints on every page,, and to add a footer showing the document number and page, and the title. If I choose to use the Excel file for purchasing, the first thing I do is delete the item column. This information is of no use if I am not using the assembly drawing.[/li]
[li]If there are any problems with the BOM on my drawing, I will delete it and re-insert it. At worst, I am ten seconds away from having a good BOM on my drawing. Any fixed item numbering scheme you try to maintain, will not survive this.[/li]
[/ol]

You can maintain your BOM manually, and manually fill in your item balloons, but what a waste of expensive software!

Inventor, Creo and SolidEdge must be similar.

--
JHG

 

[IRstuff]

Find numbers ought not be part numbers; they should be entry numbers to a table that contains part numbers

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[Compositepro]

I believe the only thing that is important about selecting find numbers is that they be fairly sequential geometrically across the drawing or assembly so that you can find them on the drawing. That is their purpose, after all.

 

[IRstuff]

Second that notion; pretty frustrating to look for find numbers randomly placed on a drawing.

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[3DDave]

I just take a few minutes and create a list of item#, qty/ref, sht, zone, view for each balloon. It solves many accounting problems. Someone needs to check to see if everything is right; might as well be right to begin with.

 

[Sparweb]

...that they be fairly sequential geometrically across the drawing or assembly...

And I thought it was just me, being obsessive-compulsive!

No, when I seriously think about it, I have seen lots of examples of find numbers (item numbers) listed in order, out of order, skipped, and grouped, and in some places given association with the part number and in others having no such association at all. The only consistent rule is that they must be unique.* Everything else is just pragmatic decisions to hopefully make the numbering easy to use. So just make a practical system that works for your organization's needs.

* Even so, sometimes two parts from two suppliers can have the same fit, form, and function. They may be interchangeable, meaning that one find number can be ballooned to one part in the drawing view, but in the BOM, the part number listed beside that find number can include multiple part numbers. Some purchasers enjoy seeing alternatives and use their judgement. Some purchasers are confused by this. It helps to know which kind of purchaser your company employs before putting alternative part numbers on a drawing.

No one believes the theory except the one who developed it. Everyone believes the experiment except the one who ran it.
STF

 

[racookpe1978]

As a user, it is very confusing (frustrating) to have skipped or missing part numbers (find numbers) because you waste time looking for the "exceptions" and missing numbers.

"I see part nbr 2,3,4,5,8,9,10. Where is 6 and 7 and why are they missing? Are they a variation not applicable to me? Or a variation very important to me this time at this plant for this modification? Are they a different material? An earlier rev? A later rev? A foulup? "

 

[drawoh]

Compositepro,

Making sorting item numbers by position on the drawing sounds incredibly difficult in SolidWorks. I have generated assembly process instructions in SolidWorks, with a separate page for each step. Since my BOM is sorted in order of assembly, I sort of achieved your sorting.

What happens if I re-use a fastener on multiple assembly steps? My CAP SCR HEX SCK A2 SST M3X0.5X8 is item[ ]3, but it is used to fasten items[ ]2, 11, 26 and[ ]27. Whatever you think of this in CAD, it is good DFMA practice.

--
JHG