Budget/ Schedule
Budget
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The budget in Appendix C reflects the total actual current cost of the project. There will be more items added as further construction takes place. The biggest changes in cost have come from the decision to scale down the project, simplify the pivot design, and save on hardware costs by buying a section of 90-degree aluminum extrusion to machine into L-brackets instead of buying the L-brackets individually. The L-brackets from McMaster-Carr cost about $5-$15 each, whereas by making them in-house the price can be reduced by approximately 75%. The decision to scale the project down was done in an effort to mitigate costs as well. Due to the fact that the design is smaller, the pivot did not need to be custom built anymore, as McMaster-Carr sells one that would be suitable for the application. This change is reflected in the overall budget.
A couple other aspects of the project that greatly affected the budget were the invention of the azimuthal axis to replace the originally planned linear actuator and the fact that freight charges were inadvertently incurred. The addition of this subassembly to the project required an additional stepper motor, more aluminum plates, a high-quality turntable, an extension for the motor shaft, shaft coupler, spur gears, and a plethora of auxiliary fasteners and hardware. More L-brackets will need to be manufactured as well, which will further increase the manufacturing time and complexity of the build. The freight charges came when ordering the aluminum rails in 10-foot lengths. It was decided to use this length because it decreased the amount of wasted material. However, McMatser-Carr does not advertise their shipping costs, and it was not made obvious that getting the material in these lengths would result in an extra $190 in shipping charges. The increased shipping costs would have, alone, paid for the majority of this project. Due to theses changes in design, and unforeseen shipping charges, the cost of this project is projected to surpass 200% of its originally anticipated costs.
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Schedule
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The general timeline for the project was to complete the entire mechanical design by the end of Fall Quarter on 12/6/2019, spend Winter quarter building the prototype, and Spring quarter is expected to be devoted to the testing, redesign, and improvement of the prototype. Due to the increase in complexity of this project, as well as other unforeseen issues, however, the mechanical design will take much longer to complete than anticipated. Most of the month of December was devoted to continuing to develop and refine the design, as well and update the Budget so that parts can be purchased. Ideally, the build phase will begin in December as well. See Appendix E for the Gantt chart that represents the approximate timeline for the project.
As of Winter quarter, eight parts were successfully manufactured. The original design for this project required approximately 25 manufactured parts, however after the addition of the azimuthal axis, the new number of manufactured parts is 44. This represents a much greater increase in the complexity of the project, as well as a tremendous increase in the amount of work required to manufacture this device in its entirety. The completed build of the prototype is expected to be done by the middle of the week before Finals during Winter quarter. This timeline will be very difficult to meet given the changes to the design of the project.
One source of problems with regards to scheduling and time conflictions was due to issues between senior project classes. The different requisites and deadlines for both senior project classes require large amounts juggling and prioritization that are difficult to remedy. This, along with the changes in design, have resulted in the majority of the drawings and parts having to be redone. This, in turn, created conflicting interactions between parts within the overall assemblies and the respective drawings. Fixing these issues represents a daunting amount of rework in which initial timelines no longer apply.