Abstract
Rapid prototyping is an emergent field that allows for the physical validation of CAD models in 3D. Originally used by architects and designers to make scale models of products and buildings, it has since grown to become a broad field that borrows many techniques from areas as diverse as modelmaking, special effects, engineering, architecture, sculpture and art. Rapid prototyping makes use of a variety of materials to achieve its goals, but it benefits especially from the near protean flexibility of plastics, which give a designer or engineer an incredible amount of freedom in how they choose to create an object. There are also many tools that get employed in the process of rapidly building functional prototypes, but easily the most iconic of these is the 3D printer. These machines can assemble any shape that will fit inside their build volume layer by layer, but they can be rather slow. Laser cutters are quite fast, on the order of minutes instead of hours or days for a 3D printer, which allows an engineer to fit many iterations into the same amount of time that it would take a 3D printer to produce 1 iteration. However, the tradeoff is that the designer needs to design in a way that accommodates the thin, flat nature of the sheets of material fed to the laser cutter. These sheets are then folded, stacked, or assembled in other ways to make the prototypes that the designer intended.
In my senior design project, I chose to work with a team of 3 other students to design, build and test a laser cutter. This is a tool that allows 2D shapes to be very rapidly cut out of a piece of material. A designer or engineer can then assemble these shapes into very precise models with a large amount of speed, helping to shorten the cycle time on design iterations and allow for more possibilities to be tested. Laser cutters are also typically quite expensive, and as a challenge we set ourselves a budget of $4,000 USD to design, build and test a functioning laser cutter. Our parameters were a 2’ x 4’ bed area, a tube power of 130W, a decently high resolution (around 800 dpi) and a timeline of 1 semester. While most mechanical engineering students have 2 semesters for senior design, we had 1 semester, due to a previous snafu that I will not get into here.
My STS topic explored the various plastics often found in single use consumer products and their effects on the environment and public perception. I found this particularly interesting, since most of what I do as a product development engineer is build one-off items that serve their purpose and are then discarded. As a citizen of the planet and an engineer with responsibility to the public good, I would like to minimize my impact on the world in the environmental sense, and so I started to examine my relationship with single-use plastics, which are often found in rapid prototyping labs, used for feeding machines such as 3D printers or laser cutters. I found out that lobbying was an integral part of how large petrochemical companies operated, that microplastics threaten the security of our food chain, and that some biodegradable straws aren’t actually all that biodegradable. I also learned that paper bags aren’t always the best alternative to plastic, and that the arrival of plastics into modern society fundamentally changed how we live, work, and play.
