Bottle Opener

Visual Summary:

Sketches

Foam Core Model

First Solidworks Drawing and Delrin Model

Second Solidworks Drawing and Delrin Model

Reflection:

The goal of this project was to design and build, with a partner, a bottle opener that could be used to open a glass soda bottle. Our design had to be cut, using a laser cutter, from a plastic sheet of Delrin. We began our design process by creating many rough sketches while discussing the features we liked and did not like. This initial phase was not very organized, but we were able to pick out aspects we liked (rounded edges and an angled handle), as well as ones we did not want to include (finger grooves). After making some measurements of a bottle cap and making a full size sketch of our bottle opener, we transferred the drawing to a piece of foam core and cut it out. At this point we noticed that the piece which would be used to pry open the bottom of the bottle cap looked like it may break, so we made a note to make it shorter and then moved on to drawing it in solidworks.

Because our design was made entirely of curved lines, transferring it into solidworks was challenging. After some trial and error we were able to draw a bottle opener similar to our original idea that we were happy with. We chose to use the 3/16” Delrin, the middle size, because we wanted it to be strong enough to withstand the force that would be put on it to open the bottle, without being too bulky. We were able to open bottles using this first iteration of our bottle opener, but it was more difficult than we wanted it to be, the handle was too close to the bottle, and it was beginning to chip. When we went back to solidworks, we made the piece that was chipping wider, angled the handle further away from the bottle, and smoothed out the shape while making it a little smaller. After filing down the edges, the second iteration of our bottle opener was much easier to use, sturdier, and more aesthetically pleasing than our first one. If we were to make another iteration, I would have liked to make the handle a little bigger, so that it is easier to hold, or get more creative with the shape and overall design of it.

Engineering Analysis: 

Although our bottle opener is not a perfect cantilever, we were able to use the cantilever equations in order to strengthen it. In order to maximize the strength of our bottle opener, specifically the piece which was used to pry up the underside of the cap, we wanted to minimize the value of the maximum stress (σmax) in our bottle opener. Because we could not change the material we were using, we had to make our σmax value lower than the yield strength for acetal, 70 MPa. In the equation for max stress, σ= FLH/2I = 6FL/BH^2, we could control the base, length, and height of our “cantilever,” but not the force. In order to minimize σmax, we wanted to have a relatively large base and height and a short length. In our final bottle opener, the height was 0.008m, the length was also 0.008m, and our base was 0.005m. With a force of 10N, the σmax value of our bottle opener is 1.5MPa, which is significantly less than the yield strength of acetal and means that our bottle opener should be strong enough to withstand the force that will be exerted upon it when it is being used to open a bottle.