Our midterm project was to create a working mechanical model using both the plasma and laser cutters. A fairly broad prompt that left a lot of room for creativity. Like usual, I couldn’t really think of any good ideas on my own so I took to Google! After looking around for “cool mechanical machines” and “laser cut mechanism” and others, I finally came up with the idea to recreate one of those hammer games that they have at carnival where you can “test your strength”. Once I had the initial idea, I went to illustrator and started drawing up some potential parts. During this process, I also had a talk with Dr. Wettergreen who said that although he liked the idea, it might be a tad too complicated to achieve and that maybe I should scale it back. Although I considered it, I still thought that while complicated, my design was still quite achievable. Oh how naive I was… Anyways, my first step was to draw the body of the person since I figured that would be one of the harder parts to get looking good. As predicted, it was difficult to get all the shapes looking right and proportional. Once I got them looking kinda how I wanted, I moved on to the game portion of the visuals which were much easier to mock up. To test how everything looked, I cut it all out of cardboard.
Next step once the visuals were mostly taken care of was the actual hard part, the mechanisms. I wanted to use rack and pinion system for the game portion but despite finding a website where I can create dxf files, (http://hessmer.org/gears/InvoluteSpurGearBuilder.html, thank you previous ENGI 210ers) I couldn’t figure out how to use those files in Illustrator. Despite the fact that google kept telling me that Illustrator was fully capable of opening dxf files, when I tried to open them, it refused to cooperate. I struggled with this for quite a while until Adulfo was able to help me open them up in solidworks and extrude the shape and save one of the faces as an .ai file. Once I finally had the rack and pinion in Illustrator, I quickly mocked up a very simple, egg shaped cam system to move the figure. I then printed all of the mechanism pieces out of cardboard and tested to make sure that the idea worked.
I found that for the most part this worked, with some small tweaks that I had to make. After this concept check, I then moved onto cutting out of wood! I first cut a box to serve as the base and the outline of the person out of wood before trying to put everything into place. After doing this, I found that my spacing between the rack and the gear as well as my spacing of the cam was slightly off. I then recut the box with the updated spacings and found that while it mostly worked, I still needed to do some sanding and other small touches to get everything working the way that I wanted. I then thought that I was pretty close to being done and started to glue some of the finalized components together. During this process, I was also making sure that everything fit together snugly and would work when I put it all together and while there was no major problems or issues, there were a lot of small things that I had to take the time to redesign or recut and I realized that I was very much not close to being done. It took a few hours to tweaks and small changes and iterations before I had something that almost, maybe was starting to resemble the final product that I wanted. Although there were many parts of it that I were not quite what I had initially imagined, I was starting to realize that my level of skill and time to redo things was simply not enough for me to be able to achieve what I wanted exactly. However, it was also a little too late for me to try to back out and change my mind so I instead went all in a committed to the design. I started cutting things out of wood like a maniac trying to get what I wanted and at one point, my work area looked like this:
(This is also by no means the worst it got, it was just the only time I remembered to take a picture.) Anyways, it is hard for me to list all of my failures and struggles simply because there were so many small issues that only became apparent later but some of them include: making all of the dowel holes slightly too small, making them slightly too big, gluing parts to the wrong side of pieces, cutting dowels and other parts too short, bending things that are drying so that it no longer fits, breaking pieces by trying to force them, and many, oh so many, more.
Eventually, after all of those trials and tribulations, I ended up with a final product that while I am proud of, I also can’t help but be slightly embarrassed by. There are so many things that I could have done better and more precisely that I can’t help but notice when I look at it. The cam could be much smoother, the dowels could be more flush, the man could be more sturdy, etc etc.
Cost Analysis:
Raw Materials:
1/4″ Birch plywood 32″x24″ (price from OEDK): $5.00
1/8″ Extruded Acrylic 2’x2′ (from OEDK): $13.48
1/4″ Steel 4″x12″ (from Home Depot): $9.87
Gel super glue 12 pack (from Amazon): $7.06
4 fl oz Wood Glue: $2.97
Total materials cost: $35.41
Labor:
Time Spent (not including drying times): 18 hours
Minimum wage in Texas: $7.25
18 * 7.25 = $130.50
Total labor cost: $130.50
Machine Time:
Plasma/Laser Cutter (couldn’t find plasma or laser cutter table rental or service price w/o requesting a quote so I found a makerspace in Houston that has a plasma and laser cutter and am using their monthly membership price): $50.00
Angle Grinder: $26.00
Total machine time cost: $76.00
Total Cost of Project: $241.91
