Jumpy extruder temperatures
Hello,
I was wondering if this is normal:
Re: Jumpy extruder temperatures
PID tune. Search the forum or look here: http://reprap.org/wiki/PID_Tuning
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Jumpy extruder temperatures
...I was wondering if this is normal...
no, it isn't !
1. check the connection between psu and rambo
2. check the connection between heatbed and rambo
3. check the connection between extruder and rambo.
maybe one of the cables is damaged and/or defective when moved.
if neither the cables are damaged, nor the connectors are loose or molten -> check if the psu delivers a constant voltage during print.
furthermore: to get rid of the little "ripples" at the graph for the extruder temperature: do a PID tuning.
and a few questions, related to the problem-> how old is your printer ? how often used ? kit or pre-assembled ?
dem inscheniör is' nix zu schwör...
Re: Jumpy extruder temperatures
looks like there is a surge on the Bed temperature before the extruder and bed turn off momentarily..
as others say, not normal
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: Jumpy extruder temperatures
yes, might be a shortage inside the heatbed. this would lead to a lower resistance -> higher current and then the voltage breaks down (cause the psu can't supply more power).
dem inscheniör is' nix zu schwör...
Re: Jumpy extruder temperatures
...I was wondering if this is normal...
no, it isn't !
1. check the connection between psu and rambo
2. check the connection between heatbed and rambo
3. check the connection between extruder and rambo.
maybe one of the cables is damaged and/or defective when moved.
if neither the cables are damaged, nor the connectors are loose or molten -> check if the psu delivers a constant voltage during print.
furthermore: to get rid of the little "ripples" at the graph for the extruder temperature: do a PID tuning.
and a few questions, related to the problem-> how old is your printer ? how often used ? kit or pre-assembled ?
It is a kit I am using for the first 12 hours.
At the moment of a longer print it looks like this:
Bed is rock solid.
No wires are loose so I will try to do a PID tuning then.
How do I check voltage?
Re: Jumpy extruder temperatures
After PID tuning extruder seems to be perfect, but now I am facing bed being too low in temp and the screen saying Sleep....
My octoprint graph:
Disclaimer: printing with PETG and should have bed turned on to 80-90'C but it never happens and stays at 75, so I just dropped it to 75.
Re: Jumpy extruder temperatures
check the voltage at the psu with a multimeter. if you don't know how and/or got no multimeter, ask a friend or colleague to help out.
at the bottom of the psu, where the terminals are, there is a little trimpot at which you can adjust the output voltage.
when you can't reach the required temperature it's most likely that the voltage is below 12V DC.
you can safely adjust the voltage to 12.6V, which will give you about 10% more heating power than at 12V.
during the adjustment of the output voltage, it is recommended to disconnect the rambo board first (unplug the power connectors), because a glitch at the trimpot could cause a short exceeding of the voltage limit that is good for the rambo board.
dem inscheniör is' nix zu schwör...
Re: Jumpy extruder temperatures
check the voltage at the psu with a multimeter. if you don't know how and/or got no multimeter, ask a friend or colleague to help out.
at the bottom of the psu, where the terminals are, there is a little trimpot at which you can adjust the output voltage.
when you can't reach the required temperature it's most likely that the voltage is below 12V DC.
you can safely adjust the voltage to 12.6V, which will give you about 10% more heating power than at 12V.
during the adjustment of the output voltage, it is recommended to disconnect the rambo board first (unplug the power connectors), because a glitch at the trimpot could cause a short exceeding of the voltage limit that is good for the rambo board.
Yup, taking apart the PSU to measure it, trimming the potentiometer to 12.62V solved the issue. Before trimming it was 12.1V. Was it too low somehow?
Re: Jumpy extruder temperatures
...
Yup, taking apart the PSU to measure it, trimming the potentiometer to 12.62V solved the issue. Before trimming it was 12.1V. Was it too low somehow?
hard to tell. there are always tolerances in the production of the heatbeds. "normally" your bed should be able to reach 100°C at 12V.
what's the voltage at the leads of your printbed, when the led is lit -> the bed is heating?
by the way: which time is at the little protocol print (which comes with the kit) given for your heatbed to reach 100°C ?
➡ keep the behaviour of your printbed under supervision. connectors and cable too.
💡 the current that the heatbed draws (approx. 15 amps, Ri = 0.8 Ohm) is at the edge of the limits of the connectors used at the rambo. and every additional tiny resistance lets you loose power (and even more dangerous: heats up the part that causes the resistance).
at my own mk2 clone i replaced the genuine cable (1.75mm²) with a thicker one (2.5mm²) to avoid unnecessary losses.
dem inscheniör is' nix zu schwör...
Re: Jumpy extruder temperatures
...
Yup, taking apart the PSU to measure it, trimming the potentiometer to 12.62V solved the issue. Before trimming it was 12.1V. Was it too low somehow?
hard to tell. there are always tolerances in the production of the heatbeds. "normally" your bed should be able to reach 100°C at 12V.
what's the voltage at the leads of your printbed, when the led is lit -> the bed is heating?
by the way: which time is at the little protocol print (which comes with the kit) given for your heatbed to reach 100°C ?
➡ keep the behaviour of your printbed under supervision. connectors and cable too.
💡 the current that the heatbed draws (approx. 15 amps, Ri = 0.8 Ohm) is at the edge of the limits of the connectors used at the rambo. and every additional tiny resistance lets you loose power (and even more dangerous: heats up the part that causes the resistance).
at my own mk2 clone i replaced the genuine cable (1.75mm²) with a thicker one (2.5mm²) to avoid unnecessary losses.
Just to revive this a little. I seem to not reach 245/90 for PETG again, at 12.6V. I don't think I should press the PSU harder?
Re: Jumpy extruder temperatures
It actually managed to catch up eventually. I don't get it.
Re: Jumpy extruder temperatures
@Murloc992, what did you do between the two cases, to get it working?
Re: Jumpy extruder temperatures
Greetings, I did PID calibration for both the bed and hotend. If you are using the newest firmware, these are included in menu now.
Re: Jumpy extruder temperatures
@murloc: did you check the temperature sensor for the heatbed ? it's assembled with kapton tape underneath the bed.
it should have a good thermal contact to the surface underneath the printbed.
dem inscheniör is' nix zu schwör...