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Irregular Infill
 
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Irregular Infill  

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duane.a
 duane.a
(@duane-a)
New Member
Irregular Infill

My third print with my new Prusa i3 MKS, and I am seeing issues with bumpy infill that is rising up in the z direction during printing. I am using Matchbox PLA, and I am using the Prusa Slic3r with the standard settings of 200um, 20% infill, and 3 shells. The infill seems to not completely fit into the empty cavity as it prints and it causes the shells to bulge outward and the infill eventually pops up and begins hitting the nozzle on successive passes. The temps are all standard and the actual readings are always within 2 degrees of the target.

See the attached photos. The rough edge is the top edge. You can see that the 3-4 upper most layers are getting more irregular. Any ideas for this cause? I went to 0% infill, which did eliminate the issue, but I cannot always print with 0% for every model.

Posted : 03/05/2017 3:56 pm
Mario
 Mario
(@mario)
Eminent Member
Re: Irregular Infill

Any chance you're extruding too much and the top layers get worse the higher you get?

Posted : 03/05/2017 8:41 pm
duane.a
 duane.a
(@duane-a)
New Member
Topic starter answered:
Re: Irregular Infill

Mario, yes that is exactly what I think is going on. Is there a control setting to back off the amount of material being extruded? Is it a temp thing? Other than over-filling infill, my prints look great.

I found this reply by Peter, on another post, that advises calibration of the nozzle feed: http://shop.prusa3d.com/forum/original-prusa-i3-mk2-f23/why-is-my-nozzle-dragging-across-all-of-my-prints--t1475.html#p11406

Posted : 05/05/2017 5:29 pm
Mario
 Mario
(@mario)
Eminent Member
Re: Irregular Infill

Quoting myself from another thread:

  • Heat the nozzle to your usual print temperature (typically around 200 or 205°C for PLA).

  • Use a ruler and measure the first 10cm of filament sticking from the top of the extruder.

  • Mark the 10cm position with a pen or a piece of crepe tape (just stick it loosely).

  • Now go to "Settings" and "Move Axis".

  • Make sure the nozzle is at least a few centimeters above the print bed, move Z axis up to be sure.

  • Move further down and pick "Extruder".

  • Note the current position (should be 0.00 after turning the printer on).

  • Use the knob to add 50.0 to the previous position (which should move the filament by 5 cm). Make sure you don#t accidently pull the tape into the extruder!.

  • Now measure the distance from the top of the extruder to the position marked before.

  • Remove the tape, in case you've used some and make sure it's all gone!

    • This typically won't result in a perfect 5cm distance.

    Use the following formula to calculate your extrusion multiplier: multiplier = 50mm / (100mm - remainingdistance)

    In my case I ended up with a remaining distance of 53mm, so the filament moved by 47mm rather than 50mm. Putting the numbers into the formula results in a factor 1.0638.

    If your calculated value is outside the 0.9-1.1 range, there might be something wrong with your filament spool or extruder (like screws too tight or loose).

    Open your slicer and in the filament settings there should be an option for the extrusion multiplier (defaulting to 1). Insert your calculated result, then try printing again.

    Posted : 06/05/2017 11:57 pm
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