Hello!
So far this is the homework I have enjoyed more, because I feel like 3D modeling softwares and knowing the diverse techniques that exist nowadays will come in handy as an engineer. For my 3D printed part, I chose a horse figure with interlocking features so it could be flexible. I took the .stl file from Thingiverse.com and downloaded it as it was. (https://www.thingiverse.com/thing:2835053)
Figure 1. .stl file of flexible horse
I first proceeded with the FDM printing, as it required less steps than SLA printing, so I thought it would be good initial practice for me, as this was the first time I 3D printed by myself. I liked Bambu studios because it was very user friendly and easy to use. After importing my file, scaling it to the correct dimensions, and slicing it, I was ready to send it to the printer. I measured my gumballs and took the approximate measurements of 1.8 in length and 2 in in height as a guide for my horse dimensions. The sizes of my horse design are 43 mm for X, 36.71 mm for Y, and 6.04 for Z, as shown in the figure below.
Figure 2. Scaling of my part on Bambu Studios software
When I was first planning to print my first horse, all the Bambu 3D printers were taken, so I opted for the other FDM orange printers that also use PLA and are located at the back of the Maker Bar (PRUSA printer). I loaded my file onto an SD card, inserted it into one of the available machines, selected my file, pressed Enter and waited for everything to be set up for printing. I stayed nearby to check the first 4-5 layers to ensure there were no printing errors and I then left the OEDK while my piece was printing.
Figure 3. PRUSA FDM printing machine using PLA
I came the next day and I got my first 3D printed horse. Confidently I then set-up my second and third print with a PRUSA printer and a Bambu printer. I definitely liked the quality and time-efficiency of the Bambu printer over the PRUSA.
Figure 4. 3D printed horse with Bambu printer (top) vs. PRUSA printer (bottom)
Here is a video of how my FDM printed horses move:
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Moreover, after having my 3 horses, I started to plan how to print my last 2 horses with the SLA printing machine. I closely followed the guiding steps stated in the homework document and was able to use the PreForm software. I set up the resin and everything I needed to, and sent my file to print. The total printing time, without counting the pre-heating, calibration, among others initial steps, was 5 hours and 32 minutes. I left the OEDK and came back 6 hours later. I took the cartridge off and put it in the washer machine that is located on the rack right below. The total washing time for my resin material was 30 minutes. After washing it, I took the two pieces out and put them in the UV light curing machine for 60 minutes and left the OEDK again. The morning after, I took the two pieces out and they looked as pictured in Figure 5.
Figure 5. 3D printed horses with SLA machine
With the appropriate scissors/forceps that were at the Maker Bar I cut the supports of both horses. I hated this process because it was long and tortuous, because why would someone use SLA printing and waste their time cutting all the supports when they can easily use the Bambu printer and just get it done faster? Of course I only refer to designs that do not require any type of support. After cutting all the supports, I noticed my horses did not have any flexibility at all compared to the previously printed ones. This is because of the resin that is used along the SLA printing, as it does not allow for highly flexible objects to be properly printed. I believe this is an excellent method to use whenever we need to have a very sturdy design or product. Also, the physical appearance (aesthetically talking) of the FDM printed objects was much better.
Figure 6. Final horse pieces post-SLA printing and support cutting
I thought I had finished but I then decided to print the two horses that I originally did with the SLA machine with the PRUSA machine, as I wanted them all to move. So, I ended up with 4 horses printed with the PRUSA machine and one horse printed with the Bambu machine, all of them made of PLA.
Figure 7. Final look of my five horses (top) and gumb balls (bottom)
Cost Analysis
I account for raw materials as white and clear PLA filament to be approximately $25 per kg, based on TexasFilamentSupply.com, and I would probably need 1 kg or 1.5 kg max. That being said, I assumed the raw material cost was $30. Additionally, machine time for the total printing of the 5 horses was approximately 2 hours and 30 minutes, and Houston facilities (from TexasFilamentSupply.com) usually charge between $20 and $30 per hour, depending on the printer’s quality. Let’s say it was $25 dollars per hour, summing up to $62.50. Finally, labor time for the engineer would be approximately 30 minutes for all the design and software set-up, summing to a total of $15 ($30/hour rate, consistent with industry standards from Glassdoor.com). Overall, my impossible objects cost $107.50, which is $21.50 per single piece.
