7. Review of Progress

7a. Schedule

A schedule was constructed near the beginning of the semester to establish goals to accomplish and deadlines to keep. Our team has been very productive so far and has been consistent with the schedule we laid out early in the semester. A physical model of the chair was completed at mid semester and proved to be very useful in completing the design of the chair. The model of the chair was presented to the class, professor and our client on 3/2/2000. Once the model was complete, testing of the motor and reclining mechanism took place. At the same time the model was being physically tested, it was being tested analytically on COSMOS/M. In addition to these tests, by hand analyses were preformed to optimize the mechanism. The building of the actual prototype was delayed due to some mandatory design changes that were needed to ensure proper functionality of the chair. Fig. 7a-1 shows the schedule of completed tasks that were preformed over the past semester.

Figure 7a-1: Spring Semester Schedule

7b. Man Hours

The vast majority of the time spent on this project was split into two categories: Shop Time and Design Work. By doing all of the machining ourselves, we were able to cut costs but in return it has slowed down our progress. Administrative work including, report writing and documentation has also consumed a considerable amount of time. Figure 7b-2 is a pie chart showing how much time was allotted to different areas of the project. At the end of the fall semester DDI had spent 950 hours on this project.

Figure 7b-1: Time allocation pie chart.

7c. Budget/Cost Analysis

The initial budget allotted to us was $2,000.00 for the whole project. We were able to save some money on parts salvaged from an old wheel chair of Bens and spent less than half of the sum we were given. The money spent can be partitioned into four different categories: raw materials and tools, pre-made components, electronics, and publishing. The cost for raw materials and tools was $250.72, which includes all steel, aluminum, and tools that were purchased to help construct the chair. The cost for pre-made components was $408.40, which includes the motor, all gears, seat belt, laterals, and other smaller components. The cost for electronic parts was $136.90, which includes all switches, relays, wires, fuses, etc. The cost for publishing was $140.41. This brings the grand total to $936.43.

We were able to stay well under budget by salvaging components from an old chair of Bens that is no longer in use. The components that we re-used were the headrest with switches, knee rest, and seat cushion, which would have cost $500.00, $100.00, $425.00 respectively. This brings the savings from salvaged parts to $1,025.00 in addition to the $525.00 saved by fabricating a custom seat back.

As mentioned previously the final construction of the EZ Journey prototype was done by members of DDI and was therefore at no cost to the client or sponsor. After completing the design of the EZ Journey car seat a master machinist was consulted to determine how much it would cost to hire a professional machinist to build one. He estimated that it would cost between $3,000 and $3,500 to build all of the custom pieces of the design. If the costs of the pre-made parts that were used in the prototype ($408.40), the price of the electronic parts ($136.90), and the price of the salvaged parts ($1,025) are added to the cost of the custom fabrication a final total of approximately $5,070 is achieved. This means that to completely replicate the final prototype built by DDI would cost just over $5,000. Changes made by different users to the seat cushion and the headrest will change this cost.