3. 3D Printing#

Goal:

  • In group, test the design rules, comment on the choice of materials and good practices for your 3D printer(s) regarding the kit parts you are going to make.
  • In group, test and set the parameters of your flexible part, so they can be combined with other classmate parts.
  • Individually, 3D print your flexible construction kit you made.
  • In group, make a compliant mechanism out of it with several hinges that do something.

PrusaSlicer#

I had my model but it was not yet ready. First, we needed to download PrusaSlicer. PrusaSlicer is an open-source slicing software that allows the conversion from STL or 3MF to a gcode by dividing the code by layers so that the 3D printer can print by layers. Then, we need to put the parameters of the prusa slicer :
drawing
I imported my model with .stl but it didn’t work because I had multiples pieces and I wanted to have them separately to rotate them. So I imported my model with .3MF (this extension allows to separate in multiples pieces). There was still a problem. The program told me my flexlink could fall and needed support. I could do a brim, but to save plastic and time I decided to change my code a little bit and put the cylinders on the edge of my flexlink like this :
drawing
I did it by adding translate([flexlink_circle,0,0]) in the flexlink module (around the two circle methods). I could now lay it flat and not use the brim for this part. However, I put a brim on the two other parts of 3mm to be sure that it doesn’t fall. You can see it in this picture :
drawing
drawing

Identify Design Parts Parameters#

For the first model I designed, I didn’t use someone else’s code, but I added the most constants that I could: plier_height, flexlink circle, flexlink size, pivot diameter, flexlink width. I did this, because in computer science we learn to put the most constants possible. It allows to easily change the code.

For the second model I designed, I took Martin Gilles’s code and to adapt it to my code I changed one variable: - Plier_height : the height of Martin’s code and mine were not the same

Printing#

Set up the 3D Printer#

Step by step:

  • Export the .gcode and put it in a SD card
  • Clean the plate
  • Check the temperature of the 3D Printer (260 degrees C°)
  • Start your program

First Attempt#

The .3MF can be found here.

I waited 19 mins and it was done. I cut the wires that were protruding and I put it all together. I tried my plier, but the flexlink kept going away with the pressure of my fingers. Finally, I found a solution and put the flexlink like the video just below instead of the two holes that I had planned.

Result#

Note : the video was 3MB and I typed this command on Linux to compress it : ffmpeg -i input.mp4 -vcodec libx265 -crf 28 output.mp4 For some obscure reasons, it didn’t work, so I tried another command : ffmpeg -i $infile -vf "scale=iw/2:ih/2" $outfile and it worked perfectly, the video is now only 0.5MB

Second Attempt#

The .3MF can be found here. What I improved :

The pivot was too big for the hole so I made the hole bigger. I sticked the flexlink to my plier instead of using 3 different pieces and tried the second design I wrote. This was the result:
drawing

Unfortunately, the flexlink broke after a few usages.
drawing