Team Vision for System-Level Design PhaseOur goals to complete for this phase:
- Finish breadfruit research - results
- Determine effectiveness of previous iterations - results
- Benchmark grinding mechanisms - see below
We've compiled information on the grinding mechanisms used for several commercially available wheat flour grinders here.
We also found an example design of a breadfruit flour grinder created by CTI. This product is not commercially available, but is deemed "emerging technology" by the company.
Morphological Chart and Alternatives
Using our functional decomposition, we identified the sub-functions that required brainstorming for possible solutions. These were compiled to make our Morphological Table
Concept Development and Selection
Alternative Design Development
Using the morphological table, we developed three concepts each with two methods for human power. This created 6 unique design options, described in detail here.
Modified Pugh Chart and Selection CriteriaThe DATUM, which is the current MET bike-powered prototype, was evaluated using the scale below. We then evaluated the system designs objectively and compared the system concepts to the scores given to the DATUM. Each selection criteria was given a weight from 0-1, with 1 being extremely important.
The rating system for each category was:
- 1 = poor
- 3 = average
- 5 = good
The weight of each criteria was multiplied by the design's score and then added to obtain a final score for each alternative.
See the updated document here
System Concept Selection
Using the Modified Pugh chart above, we narrowed down our possible designs to the "Reused Grind Stones" design, and believe we will move forward with a bike-powered version.
Feasibility: Prototyping, Analysis, Simulation
Feasibility AnalysisWe've examined several questions to assess feasibility of our concept:
- What is the minimum and ideal production rate for profitability?
- How many breadfruits are required to meet the ideal production rate?
- Can we reuse the previous team's grind stones?
Test Plan - First Cut
Current List of things to test:
- Torque needed to turn grind stones (9/26)
- Flour grain size from grind stones (10/3-10/10)
- Will our auger design clog? (10/21-11/17)
- How much the stones can grind per hour (10/21-11/17)
We've also created an energy expenditure testing plan.
Design Review Materials
Plans for next phase
Goals for the next phase:
- Preliminary design for grinding mechanism
- This will allow for further analysis of grain size
- other subsystems depend on this
- Purchase filter screens
- Discuss which sizes we want
- This will aid in testing of current grind stones to see if we can reuse them
- Preliminary design for other subsystems
- Previous versions auger clogs because it’s not large enough
- collection system
- Depends on design of the grinding mechanism
For an updated and complete project plan for the next phase, please see: