E3d v6 temperature reading low.



  • Hi everyone I am fairly new to 3d printing having started with a Tronxy x3 with the Melzi board which I managed to get working well enough to print out the mods for the y axis. On this system I could print PLA at 190 degree's.

    Over the holidays I changed from the Melzi to the Duet wifi and also upgraded the hotend to a E3d V6.
    However I seem to have a problem with the hotend temperature settings.
    I now have to increase the temperature to 215 degrees to print with the same PLA.
    I am using the ATC Semitec 104-GT2 thermistor and have my config settings as M305 P1 T100000 B4725 C7.06e-8 R4700.
    Firmware 1.19.2

    I do have a hand held themocouple temperature meter and it is showing the temperatures as aprox 50 degrees low but most of this error will be due to poor contact between probe and nozzel.

    Can anyone advise if the settings I have are correct?

    I am now trying to decide if I should fit the P100 sensor.

    Regards

    Arthur



  • PT100 is much more reliable. However, 50 deg difference is quite a lot. I'd test the resistance of your thermistor with your multimeter at room temp, then at 200, 250. Compare it to a table of known resistance for that thermistor or a graph from a datasheet. You can also put in the resistance values and the temperatures you measured them at into a spreadsheet like this one https://1drv.ms/x/s!Apv79JfGbPIwgv9DIbujMxNtMwHQpg and calculate the B value (then reassemble and test it again with the thermocouple, as below).

    Maybe you just got a bad one, or there is a bad connection somewhere. I've had a number of genuine e3d cartridge temp sensors with bad connections either where the leads enter the cartridge or at the crimped on plug. Measure the thermistor resistance at the thermistors own connector, and then back at your duet board to see if the connecting wiring is suspect.

    Put some thermal transfer paste on your thermocouple probe, and see if it will tuck into one of the holes in the heater block, then put the silicone sock over it, this should result in no more than 10-15 degrees difference. I also verify the thermocouple reading by painting one side of the heater block with a black sharpie marker and using a cheapy IR thermometer to read that temp as well. 10 degrees, either way, I can live with 50 indicates something is very much amiss.

    I actually sell PT100s in my shop, they have high temperature long leads, so no need to have any joins/plugs potentially making trouble for you, however you still need a pt100 daughterboard from Duet3D.



  • Same issue here, I now have to print PLA @ 220 deg c otherwise I get all sorts of issues. My config is the same
    [c]
    M305 P1 T100000 B4725 C7.06e-8 R4700[/c]



  • BTW you should measure the heat of the block, not the nozzle, as the thermistor is installed in the block not the nozzle. Thermal conductivity will make a difference.



  • Hello Arthur, same M305 values here. I had a similar problem, but in my case, redoing the wiring and twisting them solved the issue.

    If you want to compare both readings, the best location I've found to place the external thermocouple was inside the hole were the M3 screw tights down the thermistor cartridge.



  • Here:



  • It would be nice to measure nozzle temperature as this is as close as you can get to filament temperature as the filament is being extruded/deposited. Only one hotend actually does this, and it works quite well for it.



  • Ok I have checked the resistance at room temperature and 200 degrees both seem pretty close with 200 degrees showing 450 ohms.
    Also now getting a reading of 186 degrees when set at 200 degrees with my handheld temp probe using thermal paste and in the position suggested by Martin.
    I have just tried another print that was printed at 190 before upgrading. I started the print at 215 degrees and gradually lowered the temperature until the extruder started skipping at 205 degrees. Retraction has also been reduced to 0.8mm to avoid hot plastic being drawn back into the cold area of the nozzel.
    Looks like I will need to print at higher temps than before.

    Arthur


 

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