I have never 3D printed before. I was a bit intimidated before starting, but dove in. I chose my impossible object to be a ball inside of a rotated cube on a stand from Thingiverse, but it wasn’t one of the accepted downloaded formats the Bambu took. I tried to convert it to other forms (.obj, .stl, .svg, etc.), but the website I was using kept crashing. So, I chose a similar impossible object that’s slightly different — a ball in a box.

Note I was intimated because I sat down to begin creating the file to send to the 3D print machine and had absolutely no idea what I was doing. Until I realized that there were instructions on the homework for how to work the software! That was a highlight.

I measured the gumball container a few times and checked with my peers and their measurements when setting the dimensions for my first print on the Bambu. I set the X = 31.5mm with the scale tool, and the Y and Z measurements automatically populated because of the constraints of the design. I then also ensured the layer height was .15mm, the wall thickness was 1mm, and the infill density was 15% because the piece has small parts. I know about the function of supports but not much about creating them, so I used the auto-generate function so that the Bambu auto created supports for the piece. I then sent it off to the printer and returned about an hour later when it finished printing.

Removing the bed, I bent it so that the piece would come off, and then used the scraper tool to finish taking it off carefully.

I removed the supports near their weakest points with the plier-like tool, and was surprised to discover they came off very easily, which was encouraging.

I put the piece in the gumball capsule and found that it fit perfectly. There was no wiggle room, and I had to push the cube down so that it was tightly fitted in order to secure the top of the capsule. So, I determined I would continue on with these dimensions. There was no need to play around with scale as these worked very well.

I printed the next three on the Bambu as well with FDM. I organized the file such that three of the cubes would fit on the bed instead of just one. Now that I knew the correct dimensions, this would be more time efficient. They printed in around 2 hours and forty minutes, which is faster than over three hours if I were to print them all individually. I left to eat dinner and came back to find them in the finished prints box, which was convenient as someone had taken them off the bed very nicely.

Around the same time I printed the three with FDM, I tried to print another one on the resin printer. I sent my file to the queue, but the lab tech said it wouldn’t print automatically if in the queue.

I grabbed some gloves and researched the appropriate time to wash and then cure the clear V4.1 material. I washed it the first time for 10 minutes, as suggested. After it dried it still felt sticky so I decided to wash it again.

Afterwards, I cured it for 15 minutes on 60 C.

While the resin print was being washed twice, I removed the supports on the other three FDM prints. One of my upperclassmen friends came by to ask what I was working on, and the conversation with him prompted me to realize I needed to remove the supports on the bottom of the cube. Because I have never 3D printed, I wasn’t aware they were supports because I didn’t study the object carefully enough. I used the plier-like tool to remove the material that was holding the sphere in place for all four FDM prints. It took more time than removing the supports for the cube’s overhangs, but they also ended up coming off somewhat cleanly. However, post-processing would be required.

While the resin print was curing, I went outside with sandpaper to deal with excess material from the bottom supports on the FDM prints. I used 220 grit sandpaper as I did not want to use something too low and remove too much material, but I didn’t want to use something too fine and not remove any material. Because the rest of the print (beside the bottom) did not require sanding, I wanted to sand it just enough so that the excess was removed but some lines and imperfections were present so that the bottom didn’t appear discontinuous with the rest of the print. Below is one example of the sanded FDM print. Some lines are still present, but the material is smooth and wide gaps have been filled in a result of sanding.

I used the same tool to remove the supports on the resin print. After cutting them off, there were little nubs remaining.

On past projects, I have found myself spending unreasonable amounts of time attempting to achieve results that I could not attain. For example, on the metal diamond, I angle grinded, filed, and sand blasted so many times, but could not perfect the piece because there was not a file small enough to fit inside the negative space, and the plasma cutter left too much residue when the footballs were cut. I was set up for failure from the start. I reached a similar conclusion here. Theoretically and ideally, I would have reprinted this on the resin printer, ensuring it was washed right after it was done printing. I would’ve washed it the perfect amount of times before curing it, placing it in the machine only after it had preheated. Then I would’ve spent a lengthy period of time carefully fine tuning the surface after removing supports. But, this is a testament to the engineering design process and a lesson I’m trying to learn myself. It is unrealistic to achieve perfection when learning something brand new. And while the engineering design process desires several prototypes and adaptations, considering my perfectionism, it would be a much better use of my time to apply what I’ve learned here to the final and continue working on the midterm. Not everything is going to be perfect, and it shouldn’t always be perfect. There is something to be said about growth. I am definitely a beginner on this homework, and I believe these takeaways are a testament to my personal and academic improvement this semester.

I forgot to get a photo of my cleaned final workspace, but the last surface I worked on was the one where I post-processed the resin print. Here is a photo of the print along with four gumball capsules. After this photo was taken, I put the resin print in a capsule, put the knife away, and used this exact space to turn in my physical pieces.