Can't reach the temperature - new heater and new thermistor
Hi,
I had some issues with the printer few months ago, from that time i can not make it to print anything.
Yesterday I've bought a new heater 12V 40W and original thermistor semitec ( https://blackfrog.pl/termistor-semitec-104gt-2-w-obudowie-p-783.html ) and still max temp I can reach is 200 oC. Therefore I can't calibrate first layer.
When i hold this small fan on the left I can get 210 oC, but thats not the way to fix it.
I did run PID calibration and Temperature calibration - didn't help.
Please give me some advice, any help is appreciated.
best regards
RE: Can't reach the temperature - new heater and new thermistor
I'm attaching some photos. Maybe you'll see if something is obviously wrong, but I don't think so..
RE: Can't reach the temperature - new heater and new thermistor
Let's start with the obvious... your hot end sock is installed on the wrong side of the heat block... May not fix the problem completely but it can't help the situation...
RE: Can't reach the temperature - new heater and new thermistor
Let's start with the obvious... your hot end sock is installed on the wrong side of the heat block... May not fix the problem completely but it can't help the situation...
I wont agree - see official manual - https://manual.prusa3d.com/Guide/5.+Monta%C5%BC+ekstrudera/449?lang=en#s7071
But I have a clue. The heater i bought from auction portal may be not the same as original Prusa - as it has 13,8ohm resistance.
RE: Can't reach the temperature - new heater and new thermistor
Hi Pyby,
your hot end sock IS on upside down. 
in the picture above the red arrow points to the heat break transition zone, which is where the Hot end and the Cold end of the extruder, meet
YOU have fitted the silicone sock so that it fills this space. so whatever you do going forward, you are going to risk many more clogs ... do yourself a favour and re position the sock so that it covers the bottom of the heat block, not the top
it should look more like the picture above
now to the most likely problem for the poor heating...
you appear to have the wrong heater
Current = voltage divided by resistance on the mk2 this is 12 volts divided by 13.5 ohms which is just less than 1 amp
- wattage = amps x volts on the mk2 this is 12volts x 1 amp which is approximately 12 watts (TOO LOW to achieve the required temperature)
you need a different heater element!
(if this were the Mk3 with the 24 volt power supply, then
current would be 24/13.5 ( (1.78 amps) approximately 2 amps Wattage would be 24 x 1.78 = 42 watts ( approximately 40 watts)) - Note, Heaters are NOT linear resisters, to the actual resistance will increase with heat... consequently the actual power will be closer to 40 wast on the Mk3 printer...
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: Can't reach the temperature - new heater and new thermistor
sorry I used 13.5 ohms instead of 13.8, .. but the results are pretty much the same..
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: Can't reach the temperature - new heater and new thermistor
Hi Pyby,
your hot end sock IS on upside down.in the picture above the red arrow points to the heat break transition zone, which is where the Hot end and the Cold end of the extruder, meet
YOU have fitted the silicone sock so that it fills this space. so whatever you do going forward, you are going to risk many more clogs ... do yourself a favour and re position the sock so that it covers the bottom of the heat block, not the top
it should look more like the picture above
now to the most likely problem for the poor heating...
you appear to have the wrong heater
Current = voltage divided by resistance on the mk2 this is 12 volts divided by 13.5 ohms which is just less than 1 amp
- wattage = amps x volts on the mk2 this is 12volts x 1 amp which is approximately 12 watts (TOO LOW to achieve the required temperature)
you need a different heater element!
(if this were the Mk3 with the 24 volt power supply, then
current would be 24/13.5 ( (1.78 amps) approximately 2 amps Wattage would be 24 x 1.78 = 42 watts ( approximately 40 watts))- Note, Heaters are NOT linear resisters, to the actual resistance will increase with heat... consequently the actual power will be closer to 40 wast on the Mk3 printer...
Regards Joan
Thank you, I appreciate your help! Just small question - should I turn upside down only the silicone holding or whole block?
Should i rotate my heating block as on the picture I've attached?