Last week for Standards Tuesday I introduced you to ASME Y14.34M-1996. In case you missed it, it might be a good idea to read last week’s post before continuing. This week I will briefly describe the requirements for creating a separate parts list or BOM. ASME Y14.34M defines a Separate Parts List as:

A parts list prepared as a document separate from the engineering drawing to which it is associated and one that may be revised independently of the drawing.

There are a number of possible reasons it may necessary to have a BOM, or Parts List, separated from the drawing. Including but limited to the following:

• Company standards dictate that the BOM must be separate from the drawing
• BOM is larger then what can be effectively shown in a drawing
• BOM contents are actively updated separately from the drawing
• BOM contains a large number of items not shown in the drawing

The first scenario, company standards, is the most common reason for having a separate BOM.

Separate BOM Format

The sheet size of the separate BOM must be on one of four sizes depending on which units you use. For decimal inches, the BOM must be on size A (8.5″ x 11″) or B (11″ x 17″). If you are working in metric like the rest of the civilized world, you must use A4 (210 mm x 297 mm) or A3 (297 mm x 420 mm).

Sheet Numbering

When your BOM extends beyond one sheet you must number each sheet consecutively just as you would any other document with whole numbers, not letters. The total number of sheets must then be entered on either the first sheet, cover sheet or last sheet. When I have prepared separate BOMs, I would just use the convention of Sheet XX of YY on the footer of all pages.

If you do not wish to have the number of sheets listed on your BOM you may use a statement such as END OF LIST added to end of the list on the last sheet. That is especially helpful if the number of sheets in your document grow and shrink and the page number is not automatic.

Cover Sheets

Although not mandatory it is usually a good idea to have a cover sheet for your BOM document. A cover sheer will provide a quick overview of the document for the reader. ASME Y14.34M describes the mandatory and optional information to be listed when a cover sheet is used.

Mandatory Information for Cover Sheets

Even though covers sheets are not mandatory, when you use a cover sheet the following information is mandatory:

• LIST TYPE – On the cover sheet you must specify what type of list is being described. Even though we are concentrating on PARTS LIST, you may also use this format to describe DATA LIST, INDEX LIST, APPLICATION LIST, INDENTURED DATA LIST or WIRE LIST.
• IDENTIFYING NUMBER – The identifying number for the list must begin with letters identifying the list type. Use the letters PL, DL, IL, AL, ID or WL depending on what you have entered for the LIST TYPE.
• REVISION – Enter the document revision number here. Revision are described in ASME Y14.35M and will be covered at a later date.
• REVISION AUTHORIZATION NUMBER – When a description of change is not provided on the sheet, a number of the revision authorization must be provided. This will depend on what is used at your company, some common revision authorization documents are:

           * AN - Alteration Notice

           * ADCN - Advance Drawing Change Notice

           * CID - Change in Design

           * ECN - Engineering Change Notice

           * ECO - Engineering Change Notice

           * EN - Engineering Notice

           * EO - Engineering Order

           * NOR - Notice of Revision

• SHEET OF SHEETS – See above

Optional Information for Cover Sheets

• DESIGN ACTIVITY – Here you enter the name of the design activity as it is related to the CAGE code.
• CONTRACT NO – If a contract number associated with the parts list then this were it would go. If there are multiple contract numbers associate with this part list you do not need to put them all if it is desired.
• LIST TITLE - This is the description that is used in the engineering drawing. Even though it is only optional i would recommended adding the description here to eliminate confusion when you have multiple parts lists.
• APPROVAL – Here you may enter a handwritten signature or initials, or it may be typed; depending on your company standards.

Separate Parts List Body

The rest of the document is prepared much like a integral parts list as described in last week’s post. One way I create separate BOMs is to export a report from PDMWorks Workgroup as a tab-delimited file and import it into Excel.

Although separate are not as common as intregal parts list, they still serve there purpose. Hopefully, after reading this you will be able to create better BOM documents. This by no means is all the information covered in ASME Y14.34M-1996 but hopefully it’s a good introduction. I would recommend taking the time to explore this standard for yourself.

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