Hotend and heat bed temperature offset.
Noticed recently that my extruder was struggling to print PLA. Mid way though simple prints it would jam. ejecting the filament the end was melted but there was a section where it looks like it had solidified in the heat break.
So got out my thermocouples and started poking around. At room temp ~20C when I started the bed and hot end were reading 22C. Preheated the printer for ASA and got the following readings:
Heat bed printer reads 105C thermocouple reads 95.4C (thermocouple is located between the heat bed and metal sheet in about the same location as the heat bed thermistor.)
The hot end is even farther off hot end thermistor reads 260C thermocouple reads 244.7c (thermocouple is located in the set screw head that holds the thermistor in the hotend. Also tried putting the thermistor in the slot next to the heater and got similar readings.)
Looks like there is something wrong with the thermistor curve or readings on my printer. Is there any sort of calibration or correction I can adjust in the printer to correct for this? Not sure if it is related but I updated my printer firmware to the latest version a few days ago.
RE: Hotend and heat bed temperature offset.
Photos of the setup and readings.
RE: Hotend and heat bed temperature offset.
Hello @Wire
Did you finnaly solved?
I have the same problem form years.
See my graph of temp get from the prnter (black labels) vs a external precision temp measure device (blue line)
RE: Hotend and heat bed temperature offset.
No did not find any solution but also not seeing any print issues anymore after a full rebuild. I am wondering if they are compensating for thermal drop across the block in firmware.
RE: Hotend and heat bed temperature offset.
Interesting thread.
I have always suspected the temp on my extruder to be off by around 10 degrees or so, i can never print using the recommended temperature on the spools on for example PLA, always have to go around 10 degrees higher or i risk the plastic not melting properly (easy to spot by just extruding a plastic string, then dragging your fingernail across the surface of it to feel if it is smooth or rough)
Same applies to PETG, need to raise the temp around 10 degrees for reliable prints.
This is with a e3d copper heatblock and silicone sock.
I've posted about it a few times before here on the forums but nothing conclusive came out of it.
RE:
What kind of nozzle do you use .. brass/copper or hardened steel ?
In the later case it's normal to increase the nozzle temp. because of the lower thermal conductivity of steel vs copper alloys, although 10C seems a bit on the high side. 5 - 7C would be more usual.
If you suspect the thermistor of the hotend, why don't you try replacing it?. They aren't expensive and if nothing changes, then the fault ( if any ) must be in the Einsy board.
RE: Hotend and heat bed temperature offset.
why don't you try replacing it?. They aren't expensive and if nothing changes, then the fault ( if any ) must be in the Einsy board.
Thanks @artur5
I replaced the thermistor, but it did't solve the problem. I am thinking in replace the Einsy RAMBo board, but in my current Prusa i3 MK3 I have a hardware version v1.1a but I only can find v1.2
I am going to open a new thread at this forum to ask if some one knows if are compatible those two diferent hardware versions.