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Printrbot buildup of filament question

PostPosted: 2015-May-Sun-20-May
by bixler13
Hello all!

I just received and assembled my printrbot simple metal and all went great. I have many succesful prints and have already used all of the provided filament.

On a few of my prints, filament will build up at sharp corners. The extruder tip will hit this buildup when it passes over to other parts of the print. I have tried to print an adjustable wrench about five times once with a raft, but the small bits that turn into the worm drive get hit by the head and usually get knocked off of the print.

What parameter do I need to change to fix this problem?

I have already set the adjsted e-steps on my printer. Could it be my Z axis is too low? Temperature not set right?


Re: Printrbot buildup of filament question

PostPosted: 2015-May-Mon-01-May
by cacb
We would need to know your current settings to suggest answers to those questions. Have you measured the filament?

Re: Printrbot buildup of filament question

PostPosted: 2015-May-Mon-08-May
by Mooselake
Also check your X and Y acceleration values (around 1000 is a good value to start with), since it might be from the carriage speeding up/slowing down quicker than the extruder can compensate for. Another possibility is Z lift and/or retract on layer change is leaving a bit of a blob as the head stays in position while lifting/retracting and drips a bit.

How fast are you trying to print? What happens if you slow down?


Re: Printrbot buildup of filament question

PostPosted: 2015-May-Mon-17-May
by bixler13
I just set my retraction to 2mm and set my x and y acceleration values to 1000. I tried to print the adjustable wrench once again. Again, the extruder tip is hitting parts of the print and knocking it off. This time the print made it past the worm gear but knocked the arm from the movable tip off the print. I can still hear the clicking noises of the extruder tip hitting parts of the print.

I have measured my filament diameter and put it into Slic3r

Attached are pictures of the failed print and my current settings in slic3r and on my printrbot.

Thanks for all your help!

Re: Printrbot buildup of filament question

PostPosted: 2015-May-Tue-01-May
by cacb
The part that breaks off is the moving one that attaches the screw when finished. I am not familiar with slic3r (I use KISSlicer) and it looks like you are using an unheated bed? I could not print this one on the unheated bed.

I would suggest to switch off the raft for this print, it only makes it harder to remove the breakaway parts. From the skirt lines I think your M212 Z offset looks ok. You didn't say which temperature you are printing with, but the overall impression is that it looks fine.

In your top panel it says 2mm retraction, perhaps try to increase? Even more important may be the Z lift in that panel, if it is the feature that lifts the hotend when moving without printing. I have such a feature enabled in KISSlicer.

Re: Printrbot buildup of filament question

PostPosted: 2016-Jul-Fri-08-Jul
by milarepa
I have the same problem.
In my (relatively large) prints, it occurs at the inner side of the top layer. So, when the printer prints the edge of the inner layer, building up the part, there will be spots where the print head "stumbles" across little bumps of filament.
Did you find a solution?