I am required to create a Bill of Material for a steering system I am designing.
However, I am not entirely sure how to structure it. For example, what type of order are the parts listed as I have seen some that involve levels (I have posted below)?
I just require some knowledge from someone who has created a full list on how to write one up clearly. Also the parts circled are what I like help explaining.
What you have have posted I believe is Bill of Materials that includes Assembly level representation. Below is the complete BOM which I believe is the one you have partially referenced.
Click on image for a larger version of the image.
So if you were to create a BOM from the attached spreadsheet I would remove following line items and to create the BOM.
All of the above higher level assembly part numbers that require components like capacitors, screws, labels etc to create higher level assemblies.
A bottom up or top down approach can be followed to create assembly drawings. Below is an example for bottom up assembly structure pseudo steering system.
+-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | BOM Level | 0 | 1 | 2 | 3 | Part Number | Part Name | Revision | Quantity | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | * | | | 20-0001 | Steering System | A | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | * | | 30-0002 | Steering Wheel Assmbly | B | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-7911 | Spring | D | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-7984 | Bearing | D | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-7940 | Support | A | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-7952 | Screws | C | 10 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-7912 | Screws | A | 3 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-7918 | Hub | B | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | * | | 30-0005 | Steering Column Assembly | B | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-6002 | Flange Nut | B | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-6005 | Column Holder | A | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-6010 | Flange Bolt | C | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-6010 | Steering Joint Gromment | A | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | * | | 30-0010 | Rack and Pinion Assembly | C | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-5001 | Front Suspension Steering Ball Dust Seal | B | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-5010 | Steering Gear | A | 1 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-5020 | Front Wheel Spindle Connecting End | C | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | * | | 30-0020 | Wheel Assembly | C | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-8012 | Tire | C | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-8013 | Bolt | A | 10 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | | * | 40-8015 | Cap | C | 2 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | * | | 40-7952 | Screws | C | 20 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+ | | | | * | | 40-7912 | Screws | A | 5 | +-----------+---+---+---+---+-------------+------------------------------------------+----------+----------+
Assembly drawing of a Steering Assembly
Click on image for a larger version of the image.
References:
