3D Scanning & Printing

Cable holder

Sindoh 3D Printer
To test the design rules for our 3D printer, we were all interested in printing the thickness test and the clearance test. For thickness, we found the thinnest wall we could make was .5 mm thick, and the thinnest gap we could make was about .3 mm (Figure 4a). For clearance, our test print failed on the underside of the bar. Fortunately, I didn't really need the clearance limitations for my design; we just thought it would be interesting.

For my "print something small" project, I decided to make a cable holder that would keep the end of my phone charging cable on my nightstand instead of letting it flop to the ground when not in use. I tried FreeCAD for the first time; potentially the greatest challenge was figuring out how to navigate around my model. Some other adventures in FreeCAD:

  • I ran into some trouble filleting the edges where the cord would be pushed through. Initially, the fillet radius was 1 mm, which ended up creating intersecting/non-continuous curves and holes in my mesh. Once we figured that out, I changed the fillet radius to .5 mm, and the mesh stayed watertight.
  • Rather than use an adhesive to stick the cable holder to my nightstand, I tried to incorporate a slot for two quarters to counter the pull of the cord and keep the cable holder in place. The end result made the model look like a happy face (Figure 4b).
  • I needed the gap between the eyes of the happy face to be thinner than my charging cord so that it wouldn't escape on its own, but I also needed it to be wide enough so that I could push the cord through in the first place. My first attempt, 2 mm, was far too small, at which point I realized I only needed to make the gap slightly smaller than the cord (2.5 mm).

Getting the supports out of the coin slot (Figure 4c) proved tricky. My best method was to break the top and bottom connections with a small spackling knife then wiggle the loosened supports out with a tiny screwdriver. Then began the hunt for quarters. I did end up finding two, but I felt like I was wasting money by leaving 50 perfectly good cents on my nightstand for eternity. So I found a similarly shaped coin, 5 Bangladeshi taka, plus a smaller 1 taka coin to use instead. Here's the end result (Figure 4d).

Total time: 11h

Figure 4a

Figure 4b

Figure 4c

Figure 4d

3D Scanning

I wasn't loving the quality of the 3D Systems Sense Scanner in the shop, so I thought I would try my hand at photogrammetry using Meshroom. I learned that it didn't like the camping utensil I tried scanning first because it was too thin. I tried scanning an apple (Figure 4e), which was probably my most successful scan, but I think the white cutting board that I put it on made it too difficult for Meshroom to locate the object on the background. Lastly, I tried scanning a headlamp (Figure 4f), but I think I did an even worse job of creating a diverse background, so the headlamp was even less successful.

3D Systems Sense Scanner
I decided to go back to the 3D Systems Sense Scanner despite the poor quality. I managed to get a good scan by placing my apple on on a rotating stool. I laid some printed handouts on the stool (under the apple) to provide a distinct pattern for the camera to track. I then slowly rotated the stool to get a scan of the apple. Due to the angle at which I held the sensor, the bottom of the apple didn't scan correctly, but I was able to edit the bottom using the desktop software. The edited scan is shown in Figure 4g.

Total time: 4h

Figure 4e

Figure 4f

Figure 4g