Jason J. Gullickson

Jason J. Gullickson

Turning the corner (cleanly)

This post is about more Reprap tuning, so if you don’t find stuff like this interesting, feel free to tune in next week. The first test turned out like this:

  • Layer height: 0.254

  • First layer height: 0.35

  • Perimeter speed: 30

  • First layer temp: 190

  • Layer temp: 185

Dimensionally the part is close, the sides are within .1mm but the height is about 10.3, which has me worried I have something wrong in the firmware since I swapped out the z-rods. The thing I was trying to address are “blobs” on the corners of the Tantillus parts I printed last night. Unfortunately (?) when I printed this part with the same settings I don’t get those blobs. For now I’m continue to test to get the dimensions closer, and to address one distortion I’m seeing where the z axis changes layers. Second Test

  • Layer height: 0.25

  • First layer height: 0.25

This didn’t seem to improve the dimensional accuracy, and about 13 the way through the print left the table, so we should re-test with an initial height of .35 to see if the part sticks again. Third Test

  • First layer height: 0.35

This didn’t appear to have any effect either, but at least the part stayed on the table. Fourth Test

  • All layer temps: 190

I tried making the temp consistent across layers to see if I could get the first layer to stop shrinking relative to the others.  Visually, the part looked a little better but it didn’t make a difference in what I’m testing so I’m taking the temp back down to 185. Fifth Test

  • First layer temp: 190

  • Other layer temp: 185

  • Retract: 0

This did wonders for the distortion when the z axis is lifted, but I’m afraid that it’s going to cause stringing so adding back .3mm of retract (vs the original 1mm). Sixth Test

  • Retract: .3

This looked alright but since the cube I’m testing with won’t tell me much about stringing at this point I re-printed one of the real parts I printed last night for comparison. Seventh Test

  • Extrusion multiplier:

Lowering the extrusion multipler is a way to determine the correct e-steps you need to make sure you’re feeding the right amount of plastic in to get the right amount out; too much and you get blobs, so i’m testing reducing this.