Temperature issue after a few weeks of not using the printer
Hello,
Setup: MK3S+ with latest firmware and Prusaslicer. Polymaker ASA filament dried to 10 to 15% humidity. Printer placed in a closed garage inside a 3DUP enclosure. I print in batches for a few days and then leave the printer off for several weeks between print jobs.
Issue: Every time I start a new print job after not using the printer for a few weeks the printer gives temperature errors (MAXTEMP) and stops printing or runs way too hot and prints badly. I have to loosen the thermistor, re-insert it, and then do a PID tune for the printer to start working properly. I notice some slight buildup on the surface of the thermistor and I assume there is some in the thermistor hole in the heater block. I clean the thermistor surface every time I remove it. I did check the thermistor wire and it was fine (using a ohmmeter).
Question: Seems that having the printer in a garage promotes some type of oxidation on the thermistor's surface. Would a thermal paste help prevent this? Is it normal for this printer that its thermistor needs recalibration and reseting so often?
regards
RE: Temperature issue after a few weeks of not using the printer
If its oxidising the metal of the thermistor case then there's a good chance there's also oxidisation on other metal parts, like oh the circuit board or the power supply for example. Also the contacts on the connectors. While the wire may be fine have you also checked the resistance on the connectors themselves ?
With my Mk3 inside the house with very little humidity so no oxidation I have never had to recalibrate the hotend. The only time its been done is after something like a complete extruder rebuild where I fitted connectors to make changing parts easier. So no its not normal to recalibrate. Id be very concerned about leaving it in your garage if its causing that much oxidation.