Under extrusion and clogging
HI,
I seem to have a problem with the printer under extruding.
I've had the printer since Jan, and have been printing quite a bit with PETG. I've now switched back to PLA to print a few things and I'm having problems.
I first noticed that my extruder had a blockage as when loading the PLA filament it would curl at the extruder. Cold pulling using eSun cleaning filament did remove some carbonised muck but didn't fully fix the extrusion clog. I replaced the extruder nozzle with a new standard 0.4mm E3D and now the filament extrusion is coming out straight when loading filament.
Now prints with PLA are showing under extrusion. I normally slice with S3D, and have gone to Pruser Slic3r v 1.40.1 using the standard stock Prusa profile for PLA. Printing using Prusa White filament.
Re: Under extrusion and clogging
is your filament running free?
are your Bondtech pinch roller screws the correct tension?
is your bondtech pinch roller bearing shaft properly installed? some folk have found this to come adrift at one end!
are you using the correct Slic3r profile? the .25mm nozzle profile would give this sort of performance, if used with a .4mm nozzle in the extruder
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Under extrusion and clogging
your filament running free?
Yes. From the top using a roller bearing
are your Bondtech pinch roller screws the correct tension?
Yes. Tensioned so that the bolts are almost flush with the face.
is your bondtech pinch roller bearing shaft properly installed? some folk have found this to come adrift at one end!
Hmm...This is a Prusa built machine. Further investigation required. How would you know?
are you using the correct Slic3r profile? the .25mm nozzle profile would give this sort of performance, if used with a .4mm nozzle in the extruder
Yes. .4mm used in the Slic3r (as per the default Prusa profile)
Re: Under extrusion and clogging
Got some time to work on the printer today.
I opened the extruder idler door and found heaps of rusty dust. I followed the procedure here https://help.prusa3d.com/l/en/article/3EMxwPQU0B-bondtech-extruder-gears and now the PLA is extruding correctly.
I can only assume it was either the idler tension, or muck in the idler gears or both that was affecting the extrusion. Alignment of the gears seemed OK.
Thanks for pointing me in the right direction.
Re: Under extrusion and clogging
Cheers Simon, Glad you are back in business
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Under extrusion and clogging
I spoke too soon! It seems that I have a periodic under extrusion problem. I've spent most of the day:
- inspecting and cleaning the bondtech gears using a magnifying glass. Nothing notable here.
- adjusting the idler tension, loosened off so that it comfortably extrudes with the minimal tension
- checking that the extruder carriage screws were tight
- a full first time wizard xyz & bed re-calibration
- adjusting the first layer height
- checking the extrusion multiplier (Prusa PLA confirmed at x1.0)
- checking the extruder step ratio (adjusted from 280 to 301 steps)
The first layer is going down better down after adjusting the idler tension and the first layer height. But you can see in the pic below, that there is a periodic under extrusion showing as diagonal stripes in the first layer and also in the second layer on the other diagonal.
I thought maybe there was some crud in the bondtech that would cause it to slip on every rotation, but it's clean. I was also careful to not get any grease on the hobbed part of the bondtech. What else could be causing the periodic under extrusion?
Re: Under extrusion and clogging
I spoke too soon! It seems that I have a periodic under extrusion problem
that's not periodic, your first layer is way way way way too high.
Re: Under extrusion and clogging
Try increasing the filament temperature about 10°C. It looks like it's not flowing properly to me.
Re: Under extrusion and clogging
Ok...looks a bit better.
- Increased temp to 225 from 215
- Decreased first layer height by .1
You can see in the is still gaps in the extrusion in the second layer.
Re: Under extrusion and clogging
but there are smaller gaps...
try 5 degrees higher!
are you sure this is PLA and not say ABS?
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Under extrusion and clogging
Yep...Prusa PLA. Smells like PLA, feels like PLA.....
Increased temp 5 deg to 230. Now its looking a little worse than the previous. Notice the blobbing on the second layer?
Re: Under extrusion and clogging
Ok...wow...this was a journey!
I discovered that I had a leak between the heat block and the heat break.
For the record,
1) I disassembled the extruder whist the whole hot end was still electrically connected. I had to keep the extruder electrically connected so that I could heat up and remove the nozzle and heat break while it was hot due to all the melted plastic.
2) Once I was able to pull out the nozzle, heat break and heat sink, I then used a hot air gun to clean off all the melted plastic from the threads. I reapplied CPU thermal paste to the heat break thread and then reassembled.
3) I then reheated the whole extruder to 298 C again and tightened both the heat break and nozzle together carefully using pliers and then allowed to cool.
4) After reassembling the extruder, I then ran through the calibration of the idler and first layer again.
Yeah it works! 🙂
After I did all this, my MMU 2 turned up and I then spent the weekend taking it apart again to upgrade the extruder to R3!