PLA prints do not finish
Hi all,
My name is Brent, I am relatively new to printing with PLA (normally I print ABS). I have a PRUSA mk3S that needs to be enclosed for ABS printing.
I have 4 large parts that I needed to print for the enclosure. I already have some PLA plastic (I made sure that it was from high quality) because large parts are not easy to print with ABS without warping. 3 of those parts were already printed succesfully in PLA (nozzle temperature 215°C) but the last part is always failing and I don't know what to do...
I saw that the printer had some difficulties with finishing the print. I started great, first layer was of high quality but then, it always had a crash (against another piece of plastic coming from the print). It stops printing and after approximately 20 seconds, it returns to the print and continues (but then plastic is not extruding anymore). Some plastic is jamming the extruder i think...
I cleaned my nozzle, i cleaned the hot end (with hot and cold pulling method several times) and tried again. Now, plastic was not extruding anymore. I tried a print with ABS (to see if everything was still working as it should) and this print was succesful.
I checked the extruder and its connection (to see if no wire was stressed). There was nothing that was misorder.
Elevating the temperature (nozzle temperature was on 225°C) gave me better results (extruding plastic was again good). I do know that PLA should not be printed above 210°C but below 210°C, almost no plastic was coming out of the extruder. I thought i had fixed the problem but still, prints are not finishing (again, plastic stops extruding after crash).
Do you have any idea what might help for this problem. I am getting a bit desperate because I am clearly doing something wrong...
Can this have do something with the heat wave that we are now having in Belgium (temperature outside is now around 40°C)?
All help is appreciated!
Kind regards,
Brent
RE: PLA prints do not finish
The E3D V6 hotend is air cooled and rated to 40C ambient temps. If the temperature inside your enclosure is high enough, air cooling efficiency is reduced, temps build up in the extruder and PLA can soften nd cause friction and eventual jams. This causes the extruder motor to work harder and is one of many factors that can contribute to a heat feedback loop.
Increasing print temps improves flow, but is also adding more heat to the mix and may affect print quality and stringing.
If you haven't already, open up the enclosure doors and track ambient temps inside the enclosure.
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He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
RE: PLA prints do not finish
Have you tried going back to an earlier model that printed successfully in PLA to see if it is now having the same problem? If it fails, then you have a problem with the environment (ambient temperature, etc.) or the printer. But if it succeeds, then the problem is either with the model that is failing, or maybe an interaction between the model and something external. For example, if the model has a lot of retractions at certain layers, that will be more likely to cause issues if it is also hot in your environment.
If it is just the one model that is failing, can you provide the STL file for it?
RE: PLA prints do not finish
@brentv : Please do not double post the same in two subforums.
I've merged the two topics together.
Thomas
RE: PLA prints do not finish
Dear all,
Thanks for all your responses!! I have fixed the problem and I wanted to let you know what was causing the problem.
You have 2 little gear wheels above the PTFE tube in your extruder to pull filament in. The little gear wheel connected at the axis of the extruder motor was sometimes slipping. The little bolt that is locking this gear wheel to the axis was too loose. So when the printer had to extrude PLA, he was often not able to pull filament into the extruder (sometimes is was good but often, he could not insert any filament in the printer). After a while when filament could not be pulled in, the hot end got jammed and the 3D printer just stoppped printing (extruder head was moving but no filament was coming out). He was just moving in the air.
I am still suprised that my print in ABS was still good, even when this little gear wheel was slipping sometimes.
I have finished all my parts in PLA, I can finish my enclosure!
Thanks again for all the responses!
Best regards,
Brent
RE: PLA prints do not finish
Dear all,
Thanks for all your responses!! I have fixed the problem and I wanted to let you know what was causing the problem.
You have 2 little gear wheels above the PTFE tube in your extruder to pull filament in. The little gear wheel connected at the axis of the extruder motor was sometimes slipping. The little bolt that is locking this gear wheel to the axis was too loose. So when the printer had to extrude PLA, he was often not able to pull filament into the extruder (sometimes is was good but often, he could not insert any filament in the printer). After a while when filament could not be pulled in, the hot end got jammed and the 3D printer just stoppped printing (extruder head was moving but no filament was coming out). He was just moving in the air.
I am still suprised that my print in ABS was still good, even when this little gear wheel was slipping sometimes.
I have finished all my parts in PLA, I can finish my enclosure!
Thanks again for all the responses!
Best regards,
Brent
As mentioned in another thread, make sure that the little setscrew is tightened against the flat of the motor shaft. If the setscrew is tightened against the curve of the shaft it is much more likely to come loose in the near future.
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