With the guidance of our mentor Sagar sir, we started discussing about the pros and cons of using a square rotating shaft. The main cons were the fact that it would have only 4 cutting edges as opposed to existing machines which have at least more than 8 cutting edges. We also worried about the effect that erosion due to continuous contact with the banana stems would have on the sharp edges of the square. The main advantage of this design is that it would be extremely easy to manufacture and hence reduce the cost also.
After some more debate where we considered alternate designs, we decided to go ahead with the idea of using a square beam rotating shaft with some modifications. We would add blunt high carbon steel blades along each edge. This would reduce the cost of the material as the main beam could be made of mild steel, a cheaper metal while only the blades would be made of the more expensive metal.
We then started detailing the design and it's dimensions. Jaydeep, Vinod and Parinita worked on making the 3D CAD model of our machine for better visualisation. We also tried to calculate what would be the required power of the motor. We read a research paper that said that the force required to extract banana fibre is around 170-180N. Since we had considerable reduced the size of our shaft, we calculated that a 2HP motor would be more than sufficient to provide the required force.
Meanwhile, Tarun hit upon the idea that a possible application for banana fibre could be used in reinforcing cement blocks. He started reading up about it and asking experts about it. Meanwhile, Vibha was reviewing the literature to find out more about post-processing of banana fibre and other possible applications for the machine.
By night, the list of required materials complete with their specifications was finalised.