SafeSource : Designing a Better Safe Water Storage System

1. SafeSource:Designing a Better Safe Water Storage System Robin Davis Meryl del Rosario Joanna Natsios Paul Saindon

2. CDC – Safe Water System • Approx. 20L water vessel • Ships efficiently • Tough, robust material • Nests and stacks on palate for easy shipping • Easily carried with hands or on head • Lid • Difficult to remove • With opening large enough for filling but small enough to prevent contamination from hands • Tap for dispensing—on/off/hold Current CDC standard water vessel All citations: www.cdc.gov/safewater/faq.htm#disinfectant

3. Alternative Designs: TiO2 as antibacterial agent • Considered using TiO2 –based water purification system instead of current sodium hypochlorite (SH) system. When exposed to UV light, TiO2 exhibits bactericidal effects. • Pros • Tasteless • No risk of overdose • No harmful disinfection byproducts • TiO2 photo-oxidation is a renewable process • Purification process integrated into vessel • SH must be kept at pH11 • Cons • Requires longer periods of time for purification • Requires high surface area to volume ratio • More costly than SH ($2.40/yr per family) • Is not more effective than SH at killing bacteria

4. Thermoforming Selected Jolivert style tap Recommended HDPE, but used ASB No work on lid design Dimple for head is uncomfortable Cylindrical Bucket Last Year’s 3.082 Design Square Bucket Jolivert Tap

5. Planned Improvements • Selection of ideal polymer material • Modifications to square design • Elimination of “webbing” in areas of high curvature • Easy-to-secure, hard-to-remove lid with ergonomic handles

6. 3D Printing a Male Mold • Form solid ceramic mold from SolidWorks design • 0.1 to 0.2 mm layers of material • Layers composed of binder printed into powder • Infuse cyano-acrylate into finished product increase strength • Can withstand intense heat of thermoforming process http://209.235.222.5/articles/03/March/products/4.jpg

7. Large 3D Mold Process • The full production size is too large to create a 3D mold from the printer. • Instead several interlocking parts will be designed to fit together into a single mold that is large enough to create our piece.

8. Thermoforming • Process by which a sheet of plastic is shaped. • Has low startup cost versus other methods such as injection molding. • Is meant for small or medium scale production. Animation from: http://www.pmwproducts.com/animation/singlesheet.gif

9. Material Requirements • Able to be thermoformed • Machinable • UV and weather resistant • Safe to drink from • Resistant to chlorine and preferably other chemicals • Inexpensive

10. Material Solutions • ABS • Polycarbonate • VHMW PE • UHMW PE • PVDF Image from: http://www.caslsoft.com/

11. Comparisons Data from: McMaster-Carr http://www.mcmaster.com

12. Project Timeline • Learn SolidWorks • Create compressive elements on SolidWorks • 3D print compressive elements • Conduct compressive strength tests • Determine physical limits of mold geometry 6. Design mold of interlocking parts 7. Print 3D scale models of bucket and lid 8. Thermoform scale prototypes with various materials 9. Choose material for final bucket and lid 10. Make full-sized bucket and lid