I have a prusa i3, with a direct feed, and my friend and I are printing hexes for a game called settlers of catan which will use magnets. The problem is, that I seem to be suffering from under-extrusion and I can’t seem to identify the cause. The hex prints fine out of my friend’s Monoprice Select Mini, and the problem seems to become more and more apparent as the prints continue, with the first layer looking fair, but by the time it reaches the top, the texture is rough. I suspect my retraction settings are to blame, but I can’t seem to find something that works. My specs/settings are as follows: Nozzle: 0,4mm Layer Height: 0,2mm Infill: 20% Retraction Distance: 0,5mm Retraction Speed: 30mm/s Slicer: Cura and Slic3r both tested. Print Speed: 60mm/s Plastic: PLA (spool says 205-225*C recommended), tested in both printers with similar backgrounds. Print temp: 210*C Bed temp: 60*C I am at a loss. If anyone has better settings, or insight I am open.
PeteD
2
Do you have a guide tube that will feed the filament from one fixed point to your extruder? I had a problem that looked very similar to this where the force the extruder needed to use to pull the filament changed as the extruder moved along the X Axis. The flow rate of the plastic through the nozzle had problems when the extruder had to use greater force to feed the filament. A guide tube fixed this issue.
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I will agree that filament placement for a stock prusa isn’t ideal. I will position the filament in such a way that it doesn’t have to pull when moving on the X plane, and attempt a guide tube, and I will update here when I do so.
I followed both suggestions, and the problem is extremely improved, the parts printed are actually usable, the first layer also seems to have adopted an extremely glossy smooth look. I didn’t clean the bed as well as I thought I had before this print, and it looks like I need to add another top layer because I have a tad bit of sagging. I should modify the extruder so it uses a blower so that I can redirect the air to the print, but for now the improvement is obvious. Now I just need to figure out retraction because some stringing is now present, I cut it off with a knife before taking the pics though.
I would slow down. Cut your base speed in half (35mm/sec) and see what happens. Also do you have a cooling fan running. Looks hot. Try reducing the print temp. Also if you are getting good adhesion you can reduce the bed temp (55 maybe) after the first layer to help reduce heat.
An under extruded look can come from trying to push more filament through the extruder than it can handle. Basically speed / temp. You are at the upper end for normal PLA so slowing down is the option.
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That may also explain the sagging. I will cut the print time down and lower the temp to 200, and come back with my results.
Did you check for a clogged nozzle?
Like the others stated, check that the extruder is getting constant tension from the spool.
Also, check zero level. If you have an issue with height or a missed layer or something, it can start to air print and the layers will not stick together well and look like under extrusion a little, but still not turn into spaghetti because it only missed one layer or something.
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