<. <br>
[Experiment on the thickness limit](http://fab.cba.mit.edu/classes/MAS.863/Harvard/people/doriaspiegel/gw3.html "thickness limit experiment for bridge structure without support"). <br>
[Experiment on the angle limit](http://fab.cba.mit.edu/classes/MAS.863/Harvard/people/nicolofoppiani/Week4/week4.html "angle limit experiment for bridge structure without support"). <br>
###3D printing
####Objective <br>
To design and 3d-print a small object that could not be made subtractively.
####Metrics <br>
* 3D printer: Original Prusa i3 MK3.<br>
<img src="./3DP_prusa.JPG" alt="photo_here" width="200"/><br>
* Type of the filament: PLA
* Software and setting: PrusaSlicer was used. The nozzle speed was set to 0.30mm/s (draft).
* Design: I tried to recreate the hive structure of a melipona bee genus, native to the Amazon Basin. Hypothesis I have is that these 3D-printed structures can help bees save time to build them, therefore allowing them to focus on honey/pollen harvest.
####Protocols<br>
1. Sketch by hand to self-brainstorm the final image of what I wanted to create.
<br><img src="./pots_sketch.JPG" alt="photo_here" width="300"/><br>
2. Draw a sketch with a 3D CAD software (Fusion 360). I used Fusion 360 and made a simple two-story hive structure of melipona bees. Instead of hexagonal hive, they build and use a pot-like honey storage. I tried to recreate the structure artificially.
<br><img src="./pots_fusion_des.png" alt="photo_here" width="300"/><br>
3. Export the 3D sketch as `.stl` file. Used PrusaSlicer to slice the model. Mindful of rather lengthy duration for 3D printing, I decided to set the speed to the highest (0.30mm/s draft). Converted the `.stl` file to `.Gcode` file. Initial design did not go through the conversion because the size was too small. I doubled the size on PrusaSlicer and then it went through.
<br><img src="./pots_prusaslicer.png" alt="photo_here" width="300"/><br>
4. Plug the data in to the 3D printer. I used the default settings for PLA extrusion for temperature (215 degree celcius) and speed (100%).<br>
<iframe width="560" height="315" src="https://www.youtube.com/embed/0q_HaP2Ghqw" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><br>
####Results<br>
<br><img src="./pots_overview.JPG" alt="photo_here" width="300"/><br>
3D printing went well overall, but there are a couple of failures.
1. I ran out of the filament when the work was 90% done. It wasn't a huge problem since this was meant to be a miniature test, but in future, it would be a better practice to constantly improve my ability to guessstimate how much filament my model would need before I start.
2. The bottom part of each honey pot on the top layer did not print well because of the lack of support. When I poured water, none of them on the top layer held it. On the contrary, bottom part stored water pretty well. I think a supporting structure could have solved this problem.
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/CG93ifipazI" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
### 3D scanning (and printing)
####Objective <br>
To 3D scan an object (and optionally print it)
####Metrics <br>
<br><img src="./3dscan_artec_overview.JPG" alt="photo_here" width="300"/><br>
* 3D scanner: Artec Eva-S 3D Scanner.<br>
* Software: Artec studio 14 professional.
* Object: my ergonoic mouse.
####Protocols and results<br>
1. Place the object. Initially, I hanged my mouse for 360-dgree 3D scanning. It did not work well with the scanner and the rendered image was completely a mess. Subsequently, I simply put it on a white paper on desk.<br>
2. 3D scan the object. I slowlty rotated the white paper so that I don't have to touch the object. When the work seem to be 80% done and I could see no more improvement, I stopped scanning.
3. Edit the scanned data on the software. I let the software run the autopilot mode first to obtain 3D model that was still far from complete. Then I set the XY-plane, erase the unneccesary parts and converted the file to STL.
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/SHYsg_OfniM" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
<br>
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/AydaCEoCAFo" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
<br>
4. Since the scanning went well, I tried actually printing it. The first trial failed. As you can see below, my object was "dancing" in the air although the base layer seemed to be printed successfully.
<br><iframe width="560" height="315" src="https://www.youtube.com/embed/6iXuI6brHPI" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
<br>
5. I hypothesized that the failure was made because the dragging power of the moving extruder head became higher than the viscosity of the base layer to stick to the foundation plate. I changed two machine settings: (1) temperature from 230 degree celcius (as it was PET) to 240 degree celcius to improve the viscosity, and (2) speed from 100% to 90% to reduce the dragging power. And voila, it worked!
<br><img src="./mouse_success.JPG" alt="photo_here" width="300"/><br>
[original files](https://hu-my.sharepoint.com/:f:/g/personal/ttokunari_mde_harvard_edu/Eo_MW5iJhp1GvL7Oqn-jOrYB6G4nvFlrPQ0QWN5hT0okVg?e=J0TZIo "original files") <br>
]]>