A bill of materials is a list of the raw materials, sub-assemblies, intermediate assemblies, sub-components, parts, and the quantities of each needed to manufacture a final product (En.wikipedia.org, 2018). The bill of materials for Team Breaking Wind’s prototype is shown below in Table 4.1. A bill of materials in professionalism is valuable because the engineer, who knows which parts an assembly needs, is not in charge of purchasing. The bill of materials is then passed on to the employee who is responsible for purchasing. It is important for the bill of materials to be complete, concise, clear, and accurate. Any error or lack of clarity could cause the purchaser, who is not familiar with the assembly, to make a mistake with ordering and delay production of the prototype.
A bill of materials is directly linked to the available assets list created in Assignment 3 (See Appendix A Available Assets). For the purposes of Assignment 4, any free student workspaces likely to be used and competencies of the team will also be included to ensure buildability of the design concepts. As junior engineers, we will be utilizing the bill of materials to ensure that all necessary components have been acquired, since we are responsible for acquiring our resources ourselves.
Due to a time crunch, our plan to assemble the robot is to play to our team member’s individual strengths. Tyler Thibodeau will manufacture the wooden chassis and motor bracket since he is experienced with woodworking, he will also create CAD models for the turbine blades, hub, and wheels using Solidworks for Alex Arment to print and finish. In the meantime, Pranav Mohan will improve his ANSYS skills and assist other members with their models. Morgan Wolfe will compile everything and create the report, as well as furnish engineering drawings for all parts. All batteries, motors, and Arduino Uno components have been purchased and the cost divided evenly among all team members.
Given that we have a week and a half to complete Assignment 4 and have a meeting to discuss our prototype progress, we budgeted our time at the beginning. Based on our schedules, this left us with six solid works days to complete the prototype and report. We had planned to be finished with our prototype. We fell just short of our vision, as we still need to 3D print three more turbine blades and create the wooden motor bracket. The first two days were devoted to creating a through bill of materials and purchasing. The third work day was dedicated to CAD/FEA simulation, and the last three days were devoted to prototyping and consolidating everything into one document.
|Table 1 Bill of Materials|
|#||Part||Unit Cost||Total Cost|
|1||10 PCS 3.7V 3000mAh Rechargeable Batteries||$15.88||$15.88|
|1||Hobbypower A2212 1000kv Brushless Motor||$16.99||$16.99|
|1||5 PCS Ultrasonic Distance Measuring Sensor for Arduino Uno||$9.75/5||$1.95|
|1||RoboGets Arduino Uno R3 Compatible ATmega328P Microcontroller Card & USB Cable||$3.99||$3.99|
|1||Energizer E522 Max 9V Alkaline battery||$1.00||$1.00|
|1||3 PCS 18650 Battery Holder||$5.50||$5.50|
|1||2 PCS 9V battery Holder||$1.00/2||$.50|
|2||Mini 12V DC 35RPM 25N.cm High Torque Gear Box Motor||$14.98||$29.96|
|2||3D Printed Wheel||Free||Free|
|2||Rubber Band Tire||$0.01||$0.02|
|12||3D Printed Turbine Blade||Free||Free|
|1||3D Printed Turbine Hub||Free||Free|
|1||Birch Plywood Chassis||$0.25||$0.25|
|1||Birch Plywood Motor Bracket||$0.25||$0.25|
|Screwdriver Set||Morgan Wolfe, Tyler Thibodeau|
|Hammer||Morgan Wolfe, Tyler Thibodeau|
|Tape Measure||Morgan Wolfe, Tyler Thibodeau|
|Caliper||Morgan Wolfe, Tyler Thibodeau|
|1||Hakko FX888D-23BY Digital Soldering Station||REPF Bench Lab|
|1||Stanley 84-096 5-Inch Needle Nose Pliers||Tom Love Innovation Hub|
|1||Allen Wrench/Hex Key Set Metric & SAE Sizes||Tom Love Innovation Hub|
|Woodworking||Tom Love Innovation Hub|
|CAD Modeling||Carson Engineering Center|
|FEA Simulation||Carson Engineering Center|
|3D Printing||Tom Love Innovation Hub|
|Programming||Alex Arment Residence|
|Soldering||REPF Bench Lab|
Summing all the total costs of all the budgeted items in the bill of materials results in a final price of $76.92 including tax and shipping, putting us well under budget. All purchased goods were purchased using Amazon.com’s Prime shipping – meaning shipping is free and tax is not collected, and the final prices are as they appear. Though the wood was salvaged for free, the prices for wood are given in the interest of calculating the total manufacturing price. Wood prices are given after tax, and only include the amount of wood used rather than the total amount acquired to get the needed amount. Tools, workspaces, and competencies were not considered for the budget of the prototype construction.
In Assignment 1 we listed who possesses each competency to ensure at least one member possessed each skill needed. Here, we have listed a location for each competency to ensure buildability of our prototype. The same has been done for equipment.