6. 3D Printing and Scanning¶
Assignment: Individual assignment:
- Design and 3D print an object (small, few cm3, limited by printer time) that could not be easily made subtractively
- 3D scan an object, try to prepare it for printing (and optionally print it)
My Idea Design¶
I looked up some ideas of products that could only be made additively and I came up with this baby key chain. If I were to close the ring connecting the keys, then there would be no way to connect the components (if they were disconnected) or disconnect them (if they were connected).
I started by loading this reference image for the key. The plan was to create the key first then create a torus structure that is located through the hole. I created an offset construction plane vertical by 2 cm to create the key. I then loaded the PNG image of the key into Fusion360 and moved it a little to the right so I could build the torus from the center and have it fit inside the hole
I created an outer circle with radius 1.082 cm then extruded that by .10 cm. I then created a 3-point rectangle with two points connecting to the circle and the third point outwards by 2.569 cm with the height of the rectangle also being .10 cm. Next, I created another circle that would act as the whole when extruded it. I made this circle have a radius of 0.515 cm with the height being 0.10 cm. I clicked finish sketch and the key component was finished.
Next was the torus. I created it on the y-axis using the center line as a reference I made the diameter 3.50 cm and the thickness 0.30 cm. I aligned the shape so that it was on the x-axis and the shape was inside the whole of the key. I clicked finish sketch and the torus along with the key were connected and ready to print.
Exporting, Slicing, Printing¶
I followed these steps to take my design to the 3D printer
- Create a CAD file in Fusion360
Save this file as an STL
Open a slicer, I used PrusaSlicer
- Import the STL file
- Make sure these are checked
- Supports: Everywhere
- Go to print settings and select auto generated supports.
Before selecting auto generate supports After selecting auto generate supports
- Go to fill pattern and make it grid (or whatever takes the least amount of time or depending on what you want)
- Click export G-code then upload this file to your 3D printer.
- I prepped my 3D printer before my setting the extruder and bed temperatures
After the print finished the filament was too thin and the design snapped when removing it. I made the thickness of the material 0.40 cm instead
Once the print finished, I cleaned up the excess filament and supports and my design was done.
I downloaded the Qlone app to use on my phone for the scanning. I used this tutorial video to help guide me through the process. To use the app, I needed to print out a gridded mat to place the object on. I decided to scan a small HESS toy.
The scanning process was easy, but it took a good bit of time to get an accurate image. This is because the camera needed to stay at a set distance from the mat and when it didn’t the blue scanning image would disappear. I don’t have the steadiest hands, so the blue image would disappear then reappear.
There was an option to save the image as an STL file, but I had to get past a pay wall. If I was able to download the STL then I would upload it to google drive or drop box. From there I would download it to my computer then perform the same steps listed before. I would import it into Prusa, configure it, slice it, then print it.
Problems I Ran Into¶
- The material thickness being too thin, so the print snapped
- Not keeping a steady distance from the object when scanning
- The scan not looking the most accurate when completed
- The material not coming off easily from the printer bed
What I learned¶
I was already comfortable with using 3D printers before Fab Academy, but this experience taught me a lot. Most of my designs were flat, so the concept of bridging or overhand didn’t worry me. For this file I had to take account for all of this. I learned that you could create a bridge much farther than a overhand. This is because the filament has two resting points when bridging, unlike when creating an overhang. You can support an overhang with a support but you risk breaking the material when removing the supports (as I learned when I broke my first key). 3D printing has its advantages, like creating objects within objects, unlike with subtractive fabrication. Though it does have limitations, the time of the print and the accuracy of it. There is variation of the filament, so a 20 in x 20 in box in a CAD program might be smaller or larger than expected. Scanning also has its advantages such as bringing a real object into the 3D world that can be printed and edited. If I have a specific design for something with fine details, scanning could be better than making it from scratch in CAD software.
The assignment this week was to characterize the 3D printers in our Lab the documentation is here. Through this process I learned the different capabilities of each printer in our lab. I also learned the importance of having supports for 3D printers with extruders because the prints can be damaged if they aren’t there. I learned how to operate the resin printers in our lab also. During this process I learned what each benchmark test correlates too. The hull of the benchy test refers to the print temperature and the extruding speed, or the circle refers to the x and y-axis belts tightness, etc.
My design files area here