Molding+the+Attachment

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Design Process

The following decision matrix compares several methods of shaping plastic bottles into prosthetic parts. We decided to test each of the methods in lab because the resulting values were all relatively close.

Shaping Theoretical Decision Matrix:
Availability ||~ Time ||~ Skill/ Training ||~ Equipment/ Tooling ||~ Shape Versatility ||~ Consistency/ Repeatability ||~ Total || Oven || 3 || 2 || 3 || 3 || 2 || 3 || 2.8 || After testing, it was clear that boiling water, a propane torch and an open flame were the best shaping methods. Heating with a blow dryer did not work at all, and an open flame worked much better than expected
 * Weight || 25 || 5 || 20 || 15 || 15 || 20 || 100% ||
 * ~ Shaping Method ||~ Cost/
 * Heat Gun/Blow Dryer || 2 || 5 || 3 || 2 || 5 || 4 || 3.2 ||
 * Boiling Water || 4 || 2 || 4 || 4 || 2 || 5 || 3.8 ||
 * Fired
 * Propane Torch || 2 || 5 || 2 || 2 || 5 || 4 || 3 ||
 * Open Flame || 5 || 3 || 5 || 5 || 3 || 1 || 2.55 ||

Shaping Test Results Matrix:
Availability ||~ Time ||~ Skill/ Training ||~ Equipment/ Tooling ||~ Shape V ersatility ||~ Consistency/ Repeatability ||~ Total || It was concluded that Boiling water or an open flame were both viable options.
 * Weight || 25 || 5 || 20 || 15 || 15 || 20 || 100% ||
 * ~ Shaping Method ||~ Cost/
 * Boiling Water || 4 || 3 || 5 || 4 || 2 || 5 || 4.05 ||
 * Propane Torch || 2 || 5 || 2 || 2 || 5 || 2 || 2.6 ||
 * Open Flame || 5 || 3 || 4 || 5 || 3 || 3 || 4 ||

Then arose the debate of how to effectively attach an extension that would not only deliver an added functionality, but serve as an extension of the amputee him/herself.

---New Decision Matrices to go here---

Bottle Forming Methods

Open Flame


Mold Casting Methods: Current Approach used by the Center for International Rehabilitation media type="youtube" key="1S0FnIcXZ6s?feature=player_detailpage" height="360" width="640"

Mold Casting Methods: Appropriate Technology Approach The following decision matrix shows data from testing methods of producing a negative of an arm. Plaster will be poured into the negative to form a positive that the bottle will be shaped around. Wax molding scored highest, because of the high accuracy molds, reusable wax and fast drying time. Wax is expensive, but because it is reusable and a versatile material it's long run cost is less than clay, which is not reusable.

Molding Test Results Matrix:

 * Category Weight || 20 || 10 || 30 || 10 || 10 || 80 ||
 * ~ Molding Method ||~ Cost ||~ Set Time ||~ Shape Accuracy/ Repeatability ||~ Training ||~ Equipment and Tooling ||~ Total ||
 * Wax Negative || 10 || 10 || 34 || 8 || 8 || 70 ||
 * Clay Negative || 7 || 5 || 15 || 9 || 10 || 46 ||
 * Paper Mache Negative || 20 || 1 || 3 || 10 || 10 || 44 ||

Wax + Plaster Casting