1
$\begingroup$

I am currently printing a simple cup out of PLA (I will later anneal it). My nozzle is 0.8 mm and I'm using a 0.4 mm layer height. Unfortunately, the layers keep separating. They don't detach completely, but there are 1 layer-tall, 3-7 mm wide gaps. I increased the temperature, since my speed is 100 mm/s. I also tried decreasing cooling and increasing the flow. This only helped a little bit.

Moreover, small increases in the temperature like 230/240 °C didn't work and now I have to use 270 and even 280 °C, which is crazy, considering my layer height is 0.4 mm. Is there any easy solution that will increase the quality?

Settings:

  • Material: PLA
  • Layer height: 0.4 mm
  • Nozzle: 235 °C first layer, 270 °C for the rest.
  • Bed: 60 °C
  • Cooling: 62 %
  • Speed: 100 mm/s

I have noticed that 280 °C is better for large prints (large area, not height) and small prints look better when I change the temperature to 240/250 °C. This is how my prints look by now. The extrusion is very inconsistent, with overextrusion in the middle of the layers and gaps in the corners:

enter image description here

enter image description here

I suspect that the layer lines are not parallel to the heatbed and are over extruded, because of the high temp. I lowered it to 230 °C and there was no drooping/over extrusion, but there were more 'holes'.

Improve this question
$\endgroup$
9
  • 1
    $\begingroup$ Is it possible that your hotend cannot keep up with the flow? Hence the large temperature? $\endgroup$
    – 0scar ♦
    Apr 14 '20 at 19:21
  • $\begingroup$ The hotend is the default one that comes with Prusa MK3S. I don't know how powerful it is and I don't know how to check if that's the case. My flow is around 100 now. $\endgroup$
    – StLuke5
    Apr 14 '20 at 19:31
  • 3
    $\begingroup$ Just for troubleshooting, have you tried printing more slowly? $\endgroup$
    – Aerik
    Apr 14 '20 at 19:48
  • 3
    $\begingroup$ Wow, that is smoking hot for PLA ... $\endgroup$
    – Pᴀᴜʟsᴛᴇʀ2
    Apr 14 '20 at 19:53
  • 2
    $\begingroup$ Large nozzles can make larger heights but need to be done slower unless you have a more powerful heater or longer meltzone. $\endgroup$
    – Trish
    Apr 15 '20 at 9:29
1
$\begingroup$

After printing ~30 calibration test cubes I finally figured out the perfect settings.

  • Apparently, the extrusion width in my slicer was set to a certain number, instead of percentage. I was printing at 0.45 mm extrusion width, which was ~105 % of the 0.4 mm nozzle diameter, but less than 50 % of the 0.8 mm one. Changing the value to 130-140 % solved the majority of my printing problems.
  • As I predicted, the 230-280 ℃ nozzle temp. was ridiculously high, even with the 0.8 mm nozzle. I gradually lowered it to 210 ℃ (ironically, the value I chose at the very beginning).
  • There was some warping, so I cleaned the heatbed from the glue, put the glue again and decreased bed temp. to 50 ℃
  • Finally, I decreased the flow from 1.3 to 1.05 and everything seems perfect now.

    • Improve this answer
    $\endgroup$
    2
    • 1
      $\begingroup$ Nice that you shared your solution, this was hard to guess based on your question! This proves that stating all the print settings is a must for solving print problems. Your small extrusion width in combination with the large flow modifier mimics the wider extrusion width, but fails to do a proper job. +1 from me! Note that I still find 100 mm/s to be fast for a 0.8 mm nozzle, but of it works, go for it! $\endgroup$
      – 0scar ♦
      Apr 16 '20 at 11:20
    • $\begingroup$ @0scar Thank you! I found that larger prints required higher temperature/different settings, but luckily the most important part is done. $\endgroup$
      – StLuke5
      Apr 16 '20 at 13:05

    Your Answer

    By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

    Not the answer you're looking for? Browse other questions tagged or ask your own question.