Bill of Materials

A normal Bill of Materials (BOM) is used to purchase parts, while an Assembly BOM has more production information in it and is critical for quick-turn and time-sensitive jobs. Providing as much information in your BOM as possible helps save time and money and reduce the chance of an unexpected price increase. Please refer to the guidelines for more details.



While not required it can be helpful to list acceptable substitutions for components in the BOM in case of potential conflict. Please indicate if a component is “critical” and no substitutions are allowed.


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Assembly BOM Guidelines

  • MFG and MFG P/N, Quantity, Ref Des, Digi-key Description (Where Available), Digi-key P/N (Where Available or Other Supplier P/N, if needed).
  • Alternates in own column, not in row underneath.
  • Eliminate duplicate part numbers.
  • Confirm there are no duplicate Ref Des and amount of Ref Des matches quantity stated.
    • If there are 2 parts that install at the same location, the second installed part should state “For x” location type of thing or have an additional letter added to the Ref Des.
  • List all non-pop Ref Des on the BOM (this can either be an entire list at the bottom or in line with 0’s or DNP as the quantity needed).
  • Eliminate any assembly notes and make sure they are on the Assembly Drawing .
  • Add part ordering notes, if needed


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