1 Topic by Telemachus

  • Telemachus
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  • From: Riverside, CA
  • Registered: 2016-01-19
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Topic: Retraction Blobs

This is a repeat of a question I asked in the Titan thread, hoping to get a little bit more general feedback.  I apologize in advance for any of you that might be reading this twice.

Da vinci 1.0a.  Repetier .92.  E3D v6 with standard brass nozzle.  Titan extruder.

Inland (cheap) luminous (glow in the dark) 1.75mm PLA.

I'm printing out some glow in the dark Storm Troopers at 0.2mm layers height.  Looks nice in PLA but I'm getting these blobs at the end of moves from one side to another and some stringing.

I have retract set to 2mm length with 1mm of Zlift.  60mm/s retraction speed.

Should I slow down retraction speed or increase the length of retraction?  Lower the temp a little?

http://soliforum.com/i/?VXTdA06.jpg

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Da Vinci 1.0a.  Repetier 0.92.  E3D V6.  Titan Extruder.  Sllic3r.  Octoprint on Raspberry Pi B+.

2 Reply by wiley

  • wiley
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Re: Retraction Blobs

I would lower the extruder temp a bit - the advice I've seen is to move it down in 5 degree increments until you start seeing low temperature issues (layers don't attach, surfaces are rough). Also, be a bit careful with that retract - E3D states that 2MM is the absolute maximum you should run with their hotend because any more than that and you start pulling hot plastic into cold areas, which would blob, solidify, and then melt again.

In general, I've found that this is a pretty good guide: http://www.matterhackers.com/articles/h … ing-in-pla

3 Reply by wiley

  • wiley
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Re: Retraction Blobs

Source for the retraction info: http://wiki.e3d-online.com/index.php?ti … e_Guidance

It looks like they claim you shouldn't need more than 1mm on a direct drive setup. To me, that definitely sounds like your extruder temp is too high.

4 Reply by Telemachus (edited by Telemachus 2016-05-26 18:05:48)

  • Telemachus
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Re: Retraction Blobs

Thanks, I was just about to try 4mm of retraction, as 3mm seemed to be better, but you stopped me!  I have noticed on a test print right now that lowering the temp is helping.  I think that NOT lifting in the Z-plane might be useful as well, as the previous layer will help with the wiping off of the goop.

Alternatively, I am going to try turning OFF external perimeters first.  I don't care if the blobs are in the middle.

Da Vinci 1.0a.  Repetier 0.92.  E3D V6.  Titan Extruder.  Sllic3r.  Octoprint on Raspberry Pi B+.