3D Scanning and Printing
Group Assignment:
• Test the design rules for your 3D printer(s)
Individual Assignment:
• Design, document, and 3D print an object that could not be made subtractively (small, few cm3, limited by printer time)
• 3D scan an object (and optionally print it)
Learning Outcomes
Identify the advantages and limitations of 3D printing
Apply design methods and production processes to show your understanding of 3D printing.
Demonstrate how scanning technology can be used to digitize object(s)
Here is the schedule for the week:
Link to my schedule
Short History of 3D Printing
During class I learned about the history of 3D printing. Here's a short summary - it actually goes way back! It started in the 1930s with William Urschel's wall-building machine. From there, it evolved into the FDM printing we use today in the 1980s, all the way to the awesome RepRap project in 2008 (a 3D printer that could actually print its own parts!).
3D Printing
3D printing is basically like building with virtual LEGO blocks - you just keep adding layers to create your object!
Instead of carving material away like you do with milling, 3D printing builds things up from scratch. This makes it possible to create really complex designs, like axles, nested parts, and cool overhangs that would be almost impossible to make any other way.
Advantages and Disadvantages of 3D Printing
Advantages:
Super fast prototyping: It's great for testing out ideas quickly.
Total flexibility: It's easy to customize parts and create really complex designs that other machines can't make.
Less waste: Since it only builds up the material you actually need, it's a very efficient way to manufacture things.
Disadvantages:
Learning curve & costs: The printers can be expensive to buy at first, and you need some technical skills to get them running smoothly.
Not for mass production: It's way too slow if you want to make thousands of the exact same object.
Print limits: You're limited to certain plastic materials, you can sometimes see visible layer lines on the surface, and the final prints often need extra cleaning or sanding (post-processing) when they're done.
Group Assignment
For this week's group assignment, we started off by learning about our 3D printer in our lab. The printer in our lab is The Prusa i3 MK3. For the group assignment we tested the printer and did a clearance test and an all-in-one test.
Here is the link to the group assignment: Group Assignment
Machine Specifications
The printer in our lab is the Original Prusa i3 MK3S+. It's a Fused Filament Fabrication(FFF) 3D printer and here are its key specifications:
| Specification | Details |
|---|---|
| Build Volume | 250 × 210 × 210 mm |
| Nozzle Diameter | 0.4 mm (default) |
| Layer Resolution | 0.05 – 0.35 mm |
| Max Nozzle Temperature | 300°C |
| Max Heatbed Temperature | 120°C |
| Supported Materials | PLA, PETG, ASA, ABS, Flex |
| Frame | Sturdy powder-coated steel |
| Connectivity | SD card, USB |
| Filament Diameter | 1.75 mm |
Our local instructor Mr. Anith, Yangtshel Wangyel, and Dawa Seldon helped us a lot with this test.
Output of the Group Assignment
Clearance Test
All in One Test
Reflection on Printer Characteristics
Testing the printer taught me a lot about how and why certain prints fail.
Overhangs These start failing past 60° because the printer is basically trying to print on thin air! There isn't enough of the layer below to hold up the new plastic, so gravity takes over and it sags. By 80°, there is almost no support left, which is why it completely falls apart.
Bridging This works by cooling the plastic fast enough mid-air so it holds its shape. Short bridges are fine because the plastic hardens before gravity pulls it down. But for longer bridges, the plastic doesn't cool fast enough, so it sags.
Warping We actually dealt with this firsthand! When our lab got too cold, the plastic cooled and shrank unevenly, causing the edges of our print to lift right off the build plate. We fixed it by wrapping the printer in plastic bags to trap the heat inside.
Overall, the Prusa i3 MK3S+ did an amazing job as long as we stayed within its limits. Knowing these constraints makes it way easier to design smarter—like rotating parts to avoid steep overhangs, or splitting a big design into pieces if a bridge is too long.
THAT'S IT FOR THE GROUP ASSIGNMENT!!
Individual Assignment
Hero Video
For this week's individual assignment I decided to make an articulated shark. I first wanted to make a rough sketch of my shark but it turned out really bad.
I specifically chose this design because the articulated shark is a print-in-place mechanism where the joints are fully functional straight off the printer with no assembly needed. A milling machine can't reach inside the closed cavity to carve the joint socket, and even if both pieces were carved separately, the joint would need to pass through solid material to get into position. 3D printing solves this by growing both parts simultaneously with a small clearance gap between them.
After that I started to design my shark in Fusion 360. I wanted to use my sketch as a reference for the design but the sketch was so bad, so I decided to use a different sketch from online.
In Fusion 360 I went to INSERT > Canvas and added the image I found online.
After that I used the image as a reference and used the FORM > Cylinder to make the body of the shark.
Using the cylinder I made the body of the shark. I used different tools for making the design. I also used some help from online videos and here are the links: Video 01 and Video 02
After making the body of the shark I made a new plane to make a cut tool to create a space for the joint.
I used the combine tool to make the space for the joint.
After that I hid the unwanted body parts and also the planes.
After that I wanted to make the joint so that the shark could move. I first made a section analysis tool to have a look at a detailed level.
After making the section analysis tool I started to make the joint using a torus shape.
I copy-pasted the same torus to make the joint. And I used the offset tool to make the space for the joint in the shark's body.
After making the joint I then carefully placed the joints into the right position. I used the section analysis tool to get a better look at the joint.
I then used the combine tool to combine the joint with the shark's body.
After joining the joint with the shark's body, I wanted to make the joints stronger so I added some support using the fillet tool.
This is the final design of the shark!!!
Finally I exported the design into the slicer and exported the G-code and printed my shark.
Here are the settings I used for my shark print:
| Setting | Value |
|---|---|
| Infill | 15% |
| Infill Pattern | Gyroid |
| Supports | Yes (auto-generated) |
| Print Speed | 75% |
| Nozzle Temperature | 215°C |
| Bed Temperature | 60°C |
| Material | PLA |
Why 15% infill? The default infill in PrusaSlicer is 15%, and it is honestly the perfect balance between keeping the print strong and saving material. For most projects, 15% gives the inside enough structure so the walls don't cave in, all without wasting filament or making the print take forever.
I also had to turn on supports. The shark’s fins and some parts of the moving joints had steep overhangs that the printer just couldn't bridge over thin air. The slicer generates temporary plastic towers underneath those areas to hold them up. Once the print is finished, I can just snap those supports right off by hand!
I inserted the SD card into the printer and printed my shark.
While printing, we had to use plastic bags because the temperature in our lab wasn't suitable for the printer (it was too cold ☃️). When printing one of my friend's designs, the filament wouldn't stick to the plate properly and would cause the edges of the print/previous layers to lift. This issue is called warping, and it happens when the plastic cools and shrinks unevenly (due to low temperature 🏔️).
After finishing the print, I removed the support and cleaned the printer.
Here is the final design of the shark!!!
Here is a video of the shark moving!
3D Scanning
For this week we also had to 3D scan an object. I used Polycam for it but I had an error uploading my photos and switched to Kiri Engine.
Here are the Pros and Cons of Photogrammetry
Pros: Accessible (just a smartphone), captures colour and texture, and easy to use — Kiri Engine handles all the complex processing automatically.
Cons: Struggles with shiny or transparent surfaces, needs good even lighting, fine details often get lost, and the exported mesh usually needs cleanup before printing.
Despite these limitations, photogrammetry is a great option when you don't have access to professional scanning equipment. I first downloaded Kiri Engine from the app store.
This is the user interface of Kiri Engine. It's very simple to use and to start scanning your model, you just have to press the "+" button and you get options to scan your 3D model.
I chose the Photo Scan option and then started taking photos of the model I wanted to 3D scan.
This is the camera interface of the app. I had to take photos from different angles to get a complete view of the model. Note: To get the best result try to take photos with enough light and try to keep the model in the middle of the frame.
After that, upload your photos to start the process of making the photos into a 3D model. I prefer keeping the settings as default and just clicking upload.
After uploading and getting your 3D model, it's time to export the model. Click on export and then export the model as a .stl file.
Feel free to change the settings and your model will be sent to your email.
Here is the model I scanned. Yay!!
Files
Reflection
This week, I had a lot of fun as I got to design a model and print it. I really enjoyed the printing process and removing the support parts. I also enjoyed the 3D scanning process. But along the way I also learned a lot about the design process and the printing process.