For this assignment, I wanted to try to make an impossible knot, I thought this would work very well, as it was suited equally well to both the sla and pla printers. I also decided these prints would be more consistent and less prone to breaking with respect to the print-in-place objects that everyone else was attempting.

With my shapefile, I first looked at Thingiverse for some inspiration. I then decided that I wanted to make one of my own. I basically just wrapped a curve though 3 control point planes to create a simple knot, and then used that curve to guide a circular surface to give the curve volume. This was a very easy and short process for me. Afterwords, I just scaled the file to fit within the size of the gumball containers, and got to printing.

First, I started with PLA prints. I first used the Ultimakers, as they were the only open printers, but, after 3 failed prints, I decided to use the Prusas. My first 2 Prusa prints went well, but in one, I accidentally snipped one of the inner loops when trying to free the supports. After these, I printed 2 more without problem.

Then, I started with the SLA printers. These were at first a little scary, as I’ve never worked with the resin printers. However, they turned out to be fairly simple. I used both the Form 2 and Form 3 for my SLA prints, and they both gave consistent and good looking results.

Overall, I liked this project. I was already familiar with the FDM 3D printers from previous projects, but I’m happy to have been able to work with the resin printers for a change. I was surprised how the resin printers gave such nice print surfaces. If I need a project with a clean print surface, I will definitely be using the FormLabs printers.

Costs:

• Labor: 1 1/4 hrs = $22.50
  • CAD: 15 min @ $30/hr = $7.5
  • Print Setup: 1 hr @ $15/hr = $15.00
• Machine Time: 13 1/2 hrs (assuming ~$10/hr for print time) = $135.00
  • PLA:
    • Ultimaker: 2 hrs = $20.00
    • Prusa MK3: 4 hrs = $40.00
  • SLA:
    • Form3: 3 hrs = $30.00
    • Form2: 3 hrs = $30.00
    • Washing & Curing: 1 1/2 hr = $15.00
• Material: 9 prints = $3.66
  • Ultimaker: 3 prints @ $0.17 / print = $0.51
  • Prusa: 4 prints @ $0.16 / print = $0.64
  • Form2: 8.60 ml @ $0.149 /ml = $1.28
  • Form3: 8.25 ml @ $0.149 /ml = $1.23
• Total: $161.16