Removal of item from the BOM on a drawing face

[marshell]

I am trying to determine the correct way to show the place where an item was on a BOM when it becomes revised to have an item removed from the BOM on an assembly drawing.

Drawings are done in SW, so considered digital and not manual.

Do you:
a. put "Removed" for that item number?
b. Renumber the items.
c. line through the item.
d. Remove from the face of drawing, and not show the number used again. (item numbers could go 1,2,3,6,9,12, meaning items 4,5,7,8,19,11 were removed at one point.

I could not find a defenite answer in either ASME Y14.35 or Y14.35. The Global Eng Document referenced to put "removed" in for dash numbered parts that are removed (Inseperable assemblies I assume).

Thank you.

 

[KENAT]

Y14.34 doesn't say much at section 4.5 or 5.8 either and I didn't see it in Y14.100.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[swertel]

We just looked that up less than 3 weeks ago. Now I can't remember the spec, so forgive me for not looking it up again.

As KENAT states, it is not explicitly stated, but it is implied.

We use the wording "DELETED" for parts that have been removed from the assembly. This way, all of the find/item numbers remain and are in sequential order. For a long time, there was a requirement that you could not re-use find numbers. (Based off DOD-STD-1000 or MIL-STD-100. MIL-STD-31000 is silent on the subject.) But since parts lists can get pretty large when maintaining a lot of deleted items, we reviewed the ASME standard to get a ruling on reusing find numbers.

Our new company standard is to put "DELETED" into the parts list for parts that get removed from an assembly. We DO NOT renumber the parts lists. After at least one revision, so the DELETED notation shows up, we can reuse find numbers (assuming we add a new part to the assembly). If we were to renumber the parts list, we would have to capture all those changes in the change record. No one wants to type that much.

--Scott

http://www.wertel.pro

 

[ptruitt]

Scott,

The method you described seems as though it is a good suggestion and would be entirely logical and workable for many companies. Other companies may rely on an external database (ERP, MRP...) for the bills of materials, though, and may not show the bill on the drawing at all. The external database record may include a field for 'find' numbers, but it might be difficult to get an unassociated 'find' number to show up as 'deleted', unless "DELETED" is an actual document number which could be assigned as a 'child' to a 'parent'. This might be impossible, though, knowing that most databases do not (and should not, IMHO) allow a 'child' document number (ie: "DELETED") to be paired with a 'parent' document number more than once in a bill of materials. (Imagine what a 'where-used' would show searching on "DELETED".)

If an external database is used, I suggest that internal policies state that missing 'find' numbers indicate that a document number was deleted and that the history behind the change shall be clearly described in an ECO.

Peter Truitt
Minnesota