Printing PC Blend, Err:MAXTEMP
Hello,
I am trying to print with PC Blend (Link), but absolutely every time I try to print, I get a Err:MAXTEMP error. I am using a MK3S+, without enclosure, but this should not affect the max temperature.
Here is what happens in more details:
The bed reaches the temperature (100°C), and the nozzle too (265°C), and the print starts. As soon as the extrusion starts, the nozzle temperature starts to oscillate between 250°C and 285°C, and the oscillations get higher, between 210°C and 300°C, and eventually, it ends up going above 320°C and the Err:MAXTEMP appears. The print usually stops after 2 to 3 layers (1-2 minutes). I precise that the print I'm trying is small (1cm*2cm*4cm).
I tried different strategies, including lowering the temperature (265°C is the lowest recommended already, it was 275°C before), changing the print profile from 0.15mm SPEED to 0.15mm QUALITY to reduce print speed, also tried reducing the print speed during the print by rotating the knob during the print: I tried going to 75%, 60%, 25% of the default speed, hoping it would reduce oscillations by giving more time to the printer to stabilize, but then it was worse, the error showed 415°C after the crash. I figured out it was maybe because too low speed didn't enable the filament to absorb the heat generated by the nozzle, so I also tried increasing it to 150%, but it also crashed.
Specs:
My room temperature is about 23/24°C.
I'm using the Prusament PC Blend profile, with the prusaSlicer-2.4.2
The printer is MK3S+
The filament is PC Blend (Link above) and is new, so not wet.
Does anyone have any idea of how to solve this issue?
Thank you!
Best Answer by JoanTabb:
Have you tried running a PID Tune test at 265C?
3D printer temperature control is a relatively crude process, it is improved by tuning PID settings to try and prevent the massive swings in temperature that you are witnessing.
PID tuning is usually set up for PLA, on a new printer.
if you typically print a hotter filament you may benefit from re setting your PID Values to match that higher temperature.
I know of people who record the different PID Values for different filament types and then add them to the filament Cuatom Gcode, Start Gcode
so that when they change filaments the correct PID settings are automatically inserted.
regards Joan
RE: Printing PC Blend, Err:MAXTEMP
Have you tried running a PID Tune test at 265C?
3D printer temperature control is a relatively crude process, it is improved by tuning PID settings to try and prevent the massive swings in temperature that you are witnessing.
PID tuning is usually set up for PLA, on a new printer.
if you typically print a hotter filament you may benefit from re setting your PID Values to match that higher temperature.
I know of people who record the different PID Values for different filament types and then add them to the filament Cuatom Gcode, Start Gcode
so that when they change filaments the correct PID settings are automatically inserted.
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:
Given the massive temperature jumps from 210 to 320C, I wouldn't discard a thermistor problem. For instance, a loose cable plug in the Einsy board or a partially damaged thermistor wire with intermitent electrical contact.
RE:
Thank you @Artur5! Can this be the case even if my printer prints perfectly well PLA parts?
RE: Printing PC Blend, Err:MAXTEMP
Thank you @JoanTabb! Didn't even know I could set the PID gains myself. I haven't tried that, but I see on the prusa website that if fluctuations are higher than 5°C it might not be from PID tuning.
RE: Printing PC Blend, Err:MAXTEMP
@joantabb, I checked and the thermistor seems functional so I'd try to adapt PID gains, do you know where I can find gains for PC blend?
RE:
Solved!
I tested the thermistor with an external sensor and it seemed accurate (but not very precise).
I solved it by adjusting the PID gains. For the record, no need to find yourself a good set of PID gains, the printer can auto-tune if you go into LCD Menu -> Calibration -> PID calibration and then input the temperature you want to tune the PID for (Source).
Thanks for the help!
RE: Printing PC Blend, Err:MAXTEMP
Out of interest,
what sort of temperature variance do you see after tuning the PID?
Don't forget to retune the PID if you print a lower temperature filament!
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: Printing PC Blend, Err:MAXTEMP
In short: 260-270°C, and occasionally would go down in the range 200-240°C.
In more details: The temperature fluctuations were still (suspiciously) a bit high, I suspect that the reading of the thermistor is not precise. I set the print temperature to 265°C, and the temperature was mostly staying between 260-270°C, and occasionally, I saw readings close to 200, 210,240, but those stayed only 1 or 2 seconds, I'm not sure the nozzle can fluctuate 60°C in 1 second because of its thermal inertia, so maybe it's just a reading error. On the other hand, the filament is taking away some heat so...
RE: Printing PC Blend, Err:MAXTEMP
My PID value is tuned for PLA temperature, because this is the filament I use most. Nevertheless when printing PETg or PC there’re no temp. fluctuation issues. If 270C is the target for PC, readings from the display always stay within the 268-272C range.
I still suspect that your thermistor has a damaged wire or a loose connection. Nozzle temperatures can’t jump from 260 to 210C in two seconds, it takes at least one minute to cold down 50C when the heater cartridge is disabled.