For this project, we were tasked with making a complex machine made out of wood and metal pieces. I was working with Darrell Good on this project and we were both very excited to make something cool. We started general brainstorming to come up with a direction for the project and we kept going back to making some sort of animal. Given that the Rice mascot is an owl, we decided to go ahead and make an owl. We were inspired by the season one winner of the tv show LEGO Masters where they had a bird flapping its wings on top of a tower.

This lead us to make an owl that flapped its wings as our project. Given that we only had a rotationally spinning object to create the up and down wing motion, we knew that we needed a cam system to translate the motion. At this point we were still unsure of where to put our plasma cut piece. We knew that we had a main component being the “shoulders” of the owl. This is where the wings join with the rotating owl and go up and down with the cam rod.

Initially, we brainstormed a two cam rod system where each wing was controlled individually. After some more thinking, we decided to create a slot between each “shoulder” of the owl so that only one cam rod needed to be used. This idea seemed to be very difficult to implement given the friction of the wood, so we determined that putting gear teeth in between the “shoulders” would be best. This simplified the design and allowed us to create some custom, laser cut pieces that look very cool. We also determined that the owl would be flying after a mouse that was to be plasma cut. After the first week we had a few drawings that we later turned into CAD files and the pictures of the owl we wanted to raster in our piece.

Initial Drawings of wing mechanism and owl dimensions:

Initial CAD Models for the owl, mouse mechanism, and gears (in order):

After making the CAD files, we were able to cut some of the pieces out with cardboard. These pieces include the box that the owl stands on, the wing pieces, and all the gears/cam pieces. This allowed us to make a low fidelity version of the wings to see how they would move. This process really helped us determine the length of our main cam rod and how to align the wings. We also learned that it would be helpful to use two gears in each location as this gave greater surface area for rotation. The low fidelity prototype can be seen below :

The knowledge we gained from the low fidelity led to us making the medium fidelity prototype. This included laser cutting the box sides, mouse piece, and gears out of wood. We ran out of wood, so we ended up using cardboard for a few of the pieces in the medium fidelity. The purpose of this prototype was to finalize the alignment of the slots in the top of the mounting box so we could mount everything properly. We learned of many alignment issues with the slots as the cam rod needed to be in a different spot and the slot for the mouse was a little too small. We recycled the bearings we used in the previous prototype. Another thing we learned was that the owls needed to have a rod in between them so they wouldn’t shift during runtime and the “shoulders” would stay together. After this, we were comfortable even though we didn’t have all the parts cut in wood yet. We had the CAD files and were ready to start the final prototype. Given that the laser cutter was being heavily used, we plasma cut and finished the mouse piece during the medium fidelity phase. The medium fidelity can be seen below:

 

Finally, we started the high fidelity prototype. This involved us cutting all the pieces we had in cardboard in wood (top of box, owl, wings, and cam rod). Additionally, we had to plasma cut the mouse piece. Given that we had already worked out the issues in the medium fidelity and low fidelity steps, this process was pretty easy. The main goal here was ensuring that the raster on the owl and wings looked good. The owl was very monochromatic, so the raster had to be dark enough to make out the differences, but not too dark to where the owl was just brown. After a few test raster cuts, we settled on the settings of 100s, 80p, and the dither was set to “brighten”. One thing that we considered was how to use the laser cutter most efficiently as many people had to use it. We were able to cut everything out of one 32″ x 24″ piece of wood and then dry assemble it. The mouse piece was cut on the plasma cutter and only took one cut to get correct. We had an issue where the file wasn’t a continuous shape, so we had to work in Torchmate to join the tool paths. After plasma cutting, we used the angle grinder to get rid of the slag, sandblasted, and then applied a clear coat to the piece. The mouse graphic was also vinyl cut and put on the top of the metal piece after clear coating.

After checking that everything worked during the dry assembly, we finished the piece. We wanted to highlight the difference between the raster cut on the owl and wings and the rest of the box. That is why we went with a black stain for the box. We used tung oil on the owl and wings to give a nice finish to the wood. To prepare the wood, I sanded the box and the non-rastered surfaces with sand paper, up to 800 grit. The stain took a wile to dry and after it did we were able to assemble the entire project as seen below:

 

Video Download Below:

IMG_1943, Google drive link, Google slides link

In the end, this project went fairly smoothly as we planned everything extensively before we acted. The CAD files were edited after each prototype to enable us to have less errors. Additionally, we both had previous laser cutting experience, making the cuts efficient and nearly error free. Applying tape to the board before cutting was critical to ensure that we didn’t get any laser burn. Personally, I got much better at using Adobe Illustrator during this process and was able to efficiently create shapes and custom objects. I also got better at rapidly prototyping and coming up with solutions to problems. Another skill I got better at was using the plasma cutter as I now feel confident cutting anything. The main difficulties came along with time. Initially, we wanted to put a living hinge at the midpoint of the wing to act as the “elbow”. We created the illustrator file for this, but ended up running out of time. Another error was that I put too much black stain on the box and it took a very long time to dry. Overall, this project was a great exercise in using the tools of the OEDK and I wish I had more time to create some cool features.

Price Breakdown:

• 2-3 sheets of laser cutter wood ~ $6
• 1/8 inch steel ~ $10 for entire plate
• Bearings x 8 ~ $5
• Time (14 hrs) x 2~ $420

This is a total of ~$441 for the entire project, not including the cost of the tools used.