For this assignment we were tasked with creating an “impossible object”. This means we had to make an object that would be impossible or extremely difficult to make out of purely subtractive methods. I thought this was an interesting idea and would be a one of the easier homework.  However, ENGI 210 assignments have a special way of taking 5x longer than you anticipated.

My first idea for a design was a gyro cube. Since I was not building the object with my own hands I was focusing more on aesthetics than feasibility for this project.  After I found a design I was happy with I took the quiz and prepared my file to print. My first print did not work since the filament was not sticking to the surface. I tried calibrating and adding a raft then the next print started to work.

 

After seeing the first few layers assembled, I realized how difficult it would be to removed all the internal supports. Since the walls of the gyro cube were so thin and the support material would be the same material as the object, I figured that I would probably end up breaking my cube while trying to clear up the insides.

I then switched my design to an articulating shark.

I scaled the length of the shark down to 40mm so it would easily fit within the capsule. Since there were multiple printers broken and most others were being used by other groups or students in ENGI 210 and I didn’t want to lose my spot in the queue, I decided to print out 4 copies of the shark in one go and begin the SLA printing at the same time.  After a few hours, I checked on my pieces and the sharks were too small and most broke as I tried to separate them from the support structures. However I was able to see how much the sharks could bend in one direction and it gave me an idea of how much more I could scan up the size of the sharks in my next print.

I was confident that the shark could bend into half of its original length so I printed out 4 more copies of sharks except this time their length was 90mm. After another few hours these printed and I removed the supports with the vibrating knife and pliers. Unfortunately, they were too large to fit in the capsule when bent. One of them was very close to fitting but them the center joint broke just as it was about to close.

I then remeasured and decided a 60mm long shark would be able to fit in he capsule if it could be bent in the small manner that the 90mm models could. I printed out one 60mm long shark on the Ultimaker3 and was so sure it would fit, but now the shark was too small to bend properly and was mostly remaining straight when I tried to fit it into the capsule.

At this point I was very frustrated with myself because I knew I should have tried to space these prints out earlier and gone for an object that made more sense in with the shape of the capsule.  I knew that the sharks were not going to work anymore so I had to go back to the beginning and choose a new shape.

I now selected a simple pair of interlocked cubes because I wanted a part that at least met the requirements of the assignment, rather than just leaving it as a semi-complex failure.  I printed out 4 in the FDM printers then one copy in the SLA Form 3 printer.

At the same time my other 60mm sharks finished printing so once they all finished I removed the supports from each of the objects and tested them to see if they would fit in the capsule. I took a while to remove all the supports from the interlocked cubes but they did fit in the capsule.  It turns out the 60mm sharks were able to bend and fit in the capsule when they were printed on a prusa, but the tail was very delicate so I decided to keep moving forward with the cube design.

 

Cost Analysis:

Labor: 6 hours x $15 hourly wage = $90

Materials:

PLA Filament for FDM Prints: $1.40

1 tub SLA Resin: $20

Machine Cost: I am not including the cost of the FDM printers(Prusa-$750) and the SLA printers (Form 3- $3,500) since I am assuming my work is sending the files to a factory that already has the hardware.

 

Total Cost: $111.4

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