Laser-Cut Bottle Opener (1 of 3)

The first week of classes we were given an assignment to create a laser-cut bottle opener -- two in fact.

Objective: To be able to laser-cut a 2D shape out of Delrin sheets and use it to open actual soda bottles.

Brainstorming: How to Open and What it Should Look Like

• With past experiences with bottle openers, it seems that most try to use a level approach: there's pressure lifting one of the flaps while another point (or points) is applied on top of the cap to keep it in place. Most of my brainstorming ideas were inspired by my bottle opener back home -- it is quirky, compact and functional (look to left).
• A few ideas that we came up involved similarly closed openings but also jaw-like fixtures. My partner and I came close to 15 ideas in 5-10 minutes but we went through them all to select our top 3 favorites (in no particular order): 

1. A slim bottle opener with a jaw-like fixture to be fit across and under the bottle cap
2. A trapezoidal-shaped closed opening with a simple handle
3. Another opener with a closed shape and an ergonomic handle.

Creating a foamcore/look alike prototype:

As seen in the picture left, we create a foamcore that modeled the trapezoidal idea (#2) and the ergonomic design (#3). We measured out the dimensions of the bottle cap itself and then measured how we wanted the opening to fit around it. After we drew the opening or bottom part we imagined how we wanted to hold the handle, which affected how long and thick we wanted it to be. The little dip in the piece was an attempt to make the handle more ergonomic but we soon figured out that we couldn't effectively draw all the hills and valleys in our first design.

Hence, we discussed about making the "curves" in the handle as outward, instead of inward, and we stumbled upon making the handle of the bottle opener to look like a bottle.

Brief engineering/physics analysis:
In class, Prof. Banzaert discussed the design of a cantilever and how we would use such a design to inspire our own. Particularly, she pointed out the equation (look left) and the 4 variables to consider:

• P -- Amount of Force; force will vary from person to person and really couldn't be "measured" for the project. However, it can be noted the relative strengths of the people in a group or between partners.
• l -- the distance between the fixed end and the application of force. We took this into consideration on where the hand would grab the handle: 
• If we design a long handle where someone could apply force at the very end, our opener most likely would break; shorter is better but also we considered how much "handle" is a comfortable fit for someone to use the opener.
• Hence, our foamcore prototype's handle was measured to allow for someone to wrap three fingers around and a thumb or place their full thumb on the top surface. (My partner and I discovered that people grab things differently -- "What do you know?")
• E -- Young's Modulus or a material's distinct capability/feature to withstand a certain amount of force. We cannot change this property as we were required to use Delrin and, fortunately, the material is pretty durable.
• I -- Moment of Inertia or the cross-sectional area of the beam; we considered this slightly. We tried to stick with rectangular/trapezoidal cross-sectional areas as these seemed very common/successful for bottle openers. We designed our closed openings and leverage points around rectangular shapes and then varied the handle designs themselves.
• FYI: A smaller moment of inertia will cause more deflections which is bad. The moment of inertia for a filled rectangle is  , whereas a circular crosssection would be 

(If you're interested in learning more about applications of this cantilever equation take a look at my short analysis of the beam equation for another product design involving adaptive technology.)

SolidWorks/Laser: All three designs

In our first experience with SolidWorks, there was a lot of exploration in how we could make these shapes. I didn't realize how different it could be from AutoDesk but, now, I think I enjoy working with this software more than past ones. 

1st Design:

We embarked on creating the "Bottle" design first. It took quite a while to learn how to extrude cut, draw curved lines and use "Smart Dimension" to create the measurements we had recorded from our foamcore prototype. It even took some time to discover how to write text on the bottle and make engravings with the laser cutter. Nonetheless, we have few troubles with the actual printing of the piece.

When we finally tested our lasercut bottle opener, we discovered the opening was too big for the bottle cap, in the sense that our leverage point -- where pressure would be applied down on the cap as the other end pulled upwards -- was off center. However, we figured out that the cap came off by using the ledge (as well as the edges at the top of our "bottle" handle) to pull the flaps up, and we successfully removed 3 bottle caps in a short time. Conclusion: it didn't work as expected but it can be used to remove the bottle caps.

(For the second iteration, look at the Bottle Opener 2 post)