Professional development/Project management/Purchasing Guide

Building a bill of materials (BOM)

Your project BOM will include all components necessary to build your final product. You won't be able to do this properly without a good detailed design so that you don't miss any items. Imagine someone else is tasked with rebuilding your product, they need to be able to do so with whatever is specified in the BOM. Based on that list you will also be able to tally your total product cost.

Bill of materials

The most efficient way of compiling your BOM is in a tabular format. Here are the columns that should be included with a few examples of items:

Item name Description Units of measure Quantity Unit cost Extended cost Link
Screw M3 x 8mm Unit 4 0.1$ 0.4$ https://edu-makerlab2021.odoo.com/shop/product/socket-head-screw-metric-70#attr=375,370
Wire (5 ft) 22 awg, red Unit 1 2.5$ 2.5$ https://edu-makerlab2021.odoo.com/shop/product/wire-5ft-45?search=wire#attr=213,217
NewPing library For ultrasonic sensors Unit 1 0$ 0$ https://www.arduino.cc/reference/en/libraries/newping/
Weather API Get forecasts for different cities Unit 1 0$ 0$ https://rapidapi.com/community/api/open-weather-map
Total product cost (without taxes or shipping) 2.9$
Total product cost (including taxes and shipping) 3.28$ + 0$ shipping

There are things that you will often forget about when putting this list together, here are some tricks:

  1. Don't forget to add links to each item
  2. Don't forget the taxes
  3. Don't forget the shipping cost
  4. Don't forget to include costs of 3D printing or laser cutting materials, estimates can be found from https://makerepo.com/print_orders/index_new
  5. Include ALL items, even if they are 0$

List of equipment

You may have other items that are necessary to test your different prototypes however. For example you may need a breadboard to test a prototype but that will not be included in the final product, the breadboard would then be included in your list of equipment but not your bill of materials. Your list could look something like this:

Item name Description Type Prototype # Source
Drill press To drill holes in base Equipment 3 Brunsfield
Breadboard To test circuit Temporary material 2 MakerLab
Android studio To build app Software 2,3 https://developer.android.com/studio

Spending your Project Budget

  1. Before anything is bought by your team, a PM (project manager) or TA (teaching assistant) must approve it.
  2. When reviewing BOMs always check for:
    1. Complete list of parts, this should be representative of the designs and include fasteners and wire and everything else.
    2. Shipping and tax costs, duties can be expensive so try to buy things from Canada.
    3. If a cheaper or better alternative exists.
    4. If a cheaper supplier exists.
  3. When looking for places to find parts, here is the order of places to look:
    1. In the Makerlab (cost included in BOM).
    2. In the Makerstore (cost included in BOM).
    3. Online or local stores, some common places are below.

Online and Local Stores

General

Mechanical/hardware

Electrical/robotics