For our prototype, our group is going to 3d print our test casing so that we have more control over the shape. While Jessica and Paloma were modeling it on autocad, it was up to Kyrie and I to order the plastic. The Makerbot can use both types of mainstream thermoplastics, ABS-Acrylonitrile Butadiene Styrene- and PLA-PolyLactic Acid. But which one to chose?
ABS is a petroleum based plastic that is used in many products due to it’s light weight and resiliency. Due to it’s petroleum base, ABS smalls like melted plastic when it is being printed. It is also less stable when it i printed, and has a higher possibility of warping than PLA does. But the final printed object is more flexible and is able to bend without breaking.
PLA, on the other hand, is a plant based plastic, and apparently smells like cooking oil when it is being printed. It is also biodegradable. In addition to this, it is much more rigid plastic, and has less tendency to warp than ABS. The final object created is very hard, and has less tendency to bend than a printed ABS model. Unfortunately, this means that an object is more likely to crack than it is to bend.
All this had to be taken into account when the decision was made, and in the end we settled on ABS. Our device is meant to be carried in a purse or along with someone. This carries the high probability that it will hit and be hit by other objects. To withstand this sort of wear and tear it needed to be made out of a more flexible plastic. A self defense device is useless if it shatters inside a person’s bag.
We decided to spend $19.99 on 1 kilogram of ABS filament. This ensures that we have plenty of material to work with, should something go wrong.
Also, during our research, we ran across a device called a 3Doodler. This is a stylus that melts plastic as it is fed in, and is-in essence-a 3D printing pen. Much to Paloma’s disappointment, we decided not to buy one.