Thermistor Issues???

[kissfan4]

OK, so i have been having the oozing issue for a little while, it started out of no where, and has gotten progressively worse, i have played with temp settings, retraction amount & speed, Z lift, everything i can think of. So i decided to go buy a Infrared thermometer to check the temp of the extruder to see if it was possibly getting hotter than the readout on my printer is saying, therefore causing the oozing. First the thermometer readings are no where close to what the display on the printer is saying, and i am not sure the best way to make sure the thermometer is accurate to begin with. I have replaced the thermistor with no change to the oozing, the temp range on the filament i am using is 195-220c, i actually set a print last night to 180-185 and i was still getting oozing. I am at a loss for what to check now. Is it possible the diameter of the nozzle has gotten larger, therefore that could be causing the oozing? Any ideas would be greatly appreciated.

[zx81]

Have you tried dailing the temp down? Correct thermistor selected in the firmware? Contactless thermometers detect infrared light for there temperature readings. reflective metal messes with the accuracy! If you have a multimeter check the resistance of the thermistor and check it against the datasheet for the thermistor… or use a k type probe and temp meter.

[kissfan4]

I believe the thermistor setting is correct, nothing changed before i swapped the thermistor.

[SOC3D]

Have you run a PID autotune routine on you hotend? Your thermometer readings using infrared on the outside of a heater block or nozzle will not be the same as your thermistor. Depending on the type of thermometer it may also have a huge reading varience at higher temps. Remember that your thermistor is inside the aluminum block and close to the heating element. If you want to dial in temps manually and check your thermistor accuracy you can do this in a less technological way. Turn the hotend up to about 120 celcius. Feed in some filament, PLA I’m assuming? Try to push the filament through the nozzle. Increase the nozzle temp by 5 degrees every minute or so until you are able to push the filament through the nozzle. Leave the nozzle at that temp and push some filament through every 15 seconds or so. If you are getting a consistent string (or blob and string) on each push your temps are likely stable.

[kissfan4]

i understand the temps being cooler on the outside of the heater block, but we are talking only getting a reading of 80c on the thermomter, i am going to try and paint one side of the heater block black in color to avoid any issues with reflection. I also have some new thermistors and thermal compound on order to see if that helps, but it drives me crazy that this issue has just recently surfaced. I will give the manual adjustment a try, since i am not real comfortable with messing with the firmware.

[SOC3D]

PID tuning should not involve firmware. It’s just M303 C(count of cycles) E(extruder usually 0) S(desired temperature) Most modern firmwares you can save the results with M500 for others there is a gcode to set the KP ki and kd values into eeprom or at the start of each print in your slicer. No firmware playing needed.

[kissfan4]

So i tore into the printer last night, the nozzle is extremely wore out so i installed a replacement, but i am also having bearing issues so i was unable to give it try.