Hi something wrong start happening with my printer axactly with nozzle temperature,

3D Printing
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Hi something wrong start happening with my printer axactly with nozzle temperature, is start oscillating up to sometimes 7 degrees up and down ,my first thought was the thermistor is going to die, so i only replaced him for new ,but still same issue persist, any idea what next should i do with this problem ,printer is a arduino marlin software, never had this issue before

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Did you check the connections to the heating element as well? Could be intermittent contact problems die to thermal expansion and contraction.

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Yes all look fine and solid by mesurment tool and my eyes

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@Jonathan_Knirsch
Thanks this was in my head to do either as next step just ,why thru 3 years of ussing without this problem this occurred now, but everything is possible

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Needs a PID tune up. Things wear in/out over time and need adjusting.

Here are some basic rules for making manual adjustments based on different behaviors you might see. Make your changes in increments of 2-3% of the values for your PID settings.

  • if the temperature is getting too hot before settling down, increase Kd and decrease Kp (more creeping up on the temperature and less muscling it around)

  • if the temperature tapers off just under the target and never quite reaches it, decrease Kd and increase Ki (less creeping up alongside the target, and more correction for cumulative offset) Increasing Ki means that cruising just a hair under the target for a long time will cause Ki to gradually put more power into the heater until it reaches the target. A higher Kd would fight this process by decreasing power to get the measured temperature curve parallel to the target temperature line.

  • if the temperatures are taking a long time to settle, oscillating or hunting indefinitely, decrease Ki and increase Kd (less agitation from cumulative error, and more gliding into alignment with the target); alternatively try decreasing all three terms… the PID equivalent of taking some deep breaths and relaxing the amount of control you’re exerting

For more on the topic you can read here: http://rigidtalk.com/wiki/index.php?title=PID_tuning

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Thanks for all help, i checked my default marlin software and yes settings for pid was default for ultimaker so pid tunning never was done acurate for my hotend, after pid tunning done temperatures fluctuations drop to 3 degrees up and down ,wich mean that pid tunning improve my situation, now im gonna improve it more as described by Jeff Parish post ,and fingers cross all back to normal, thanks again