HELP!!!
I use an ultimaker 3 extended with a 2.5 extruder and silver PLA, but can’t figure out how to fix my print. The corners of the first pic has these flat circles on the end and the second pic coming closer to the middle of the dome it’s not smooth. If anyone can recommend settings or help, this 18mm *18mm knob it will help kickoff my 3d printing section. Thank you very much.
First pic looks to have retraction blobs. For the second pic is this the bottom surface of the same part?
Which firmware version? Which Cura version? Changed any default settings? Which quality setting?
And what’s a “2.5 extruder”?
@Adam_Steinmark It is the bottom of the first part, its supose to be a a dome with a 2 mm hole in the middle for a helicoil. But as you can see closer to the middle there are filament strands
I’m having a little trouble trying to understand. Does the hole go all the way through? You may have flipped triangles. Can you provide your STL and gcode file? Easiest way to share it would be to upload them to a folder in Google Drive or Dropbox and post a public link to the folder here.
@Daid_Braam latest firmware, default play settings and 2.5 print head
You only linked the STL file and not the gcode so I can’t be sure but I believe the pillar in the middle of the hole is support structure.
Why is there a vote option?
@Kevin_Danger_Powers I just added the pic, not sure why vote option came up
You mean a 0.25mm nozzle? How large is this print? 2cm?
@Daid_Braam 1.8 cm actually
Your layer overhang towards the top of the dome is more than your nozzle width at the layer height you are printing at. Decrease the layer height as small as you can. Or, you can turn on a dense (35%) support material structure and set it to something like 45 degrees.
You will actually get a better dome shell like this with a 0.4 mm nozzle and a small layer height than with a smaller nozzle.
Another trick is to put a 0.2mm thick membrane across the hole that you cut out later. Makes for a much crisper hole and removes the semi-floating aspect of it.
You might be slightly over extruding given the look of the top side of the part. Have you run a thermal calibration on your filament?
Might also need to speed up your retraction rate a little bit.
Thanks for all the recommendations I will give them a try. Can you believe that this knob is a $3k replacement for an F-15, that’s why I am trying to get it perfect. I will post updated pic when I can. Thanks.
@Jeff_Parish I figured a smaller nozzle would produce better results. The pilot operates this knob by touch, so I was trying to reduce additional layer distraction.
@Adrian_Rampersad Just printed it using a 0.4mm nozzle and 0.05mm layer height. Came out pretty nice. Using supports for that shallow of a dome makes it a pain to remove. The dish out in the bottom is a little rough still because of them. Could be sanded.
For a more perfect surface is a two part assembly an option?
@Jeff_Parish Was you able to eliminate or reduce the retraction blobs? And yes the dome is a pain, I was only able to print it in PLA, I tried CPE+ for strength but the supports kept fusing to the dome. Would you be able to post a pic of your print?
@Adrian_Rampersad No retraction or end stop blobs like what you are seeing but I did have a few strings between the corners where a minimal amount of material was being printed at the tops of the little ridges. These I brushed off. My minimal travel before retracting was set to 1mm and could be lower to help tune that out. My printer has a direct drive unlike your bowden so my retraction settings are 2.5mm and 30mm/s which typically serve me very well. Here are some pictures of the top and bottom.
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Ah, one picture at a time…
You can see that the last remnants of the support material are still there. They did not break off very cleanly due to how shallow the bowl is.
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