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Hi everyone, I’m new on the forum and this is my very first post. I apologize for any possible writing mistake as I’m not a native English speaker.

I bought a CTC printer (Black wooden frame, with dual MK8 extruder and ATmega2560) around 2 months ago, great product for such a limited price! However, I start to meet with some annoying problems quite soon, which seems to be quite the standard with this printer (and probably any cheap printer out there).

After dismounting and reassembling the extruders block, I noticed that the temperature is now failing to stay at setpoint and overshooting occurs (on both extruders!). The overshoot is around 10 -15 degrees (can be even 20) and then the temperature slowly goes down to original setpoint. Sometimes in the past I had the same problem, which turned out to be related to loose assembly of thermocouple on heater block. This time it is different, since I double checked everything and the thermocouple is firmly attached to the aluminium insulated block. the thermocuples are fine (right T at room T and at higher temperature) and the problem occurs even replacing with other K-type thermocouples. I also checked the heat cartridges, there is no evident breakage of cables (although I can’t test the output power since I have no tools).

I tried to modify PID for both the extruders, but since CTC has no true PID control the initial heating (before it gets at 10 C from setpoint and PID starts to work), I only managed to limit the overshooting to 7 - 8 C but no further improvements are achieved.

I read somewhere that is possible to change PMW max for the heaters, to set the cartridge power a bit lower and avoid overshooting when outside the PID control range. Do you know if is possible to do it with CTC (Sailfish 7.7) and the how-to for such a procedure?

Looking forward for someone’s reply, I wish you all a nice day (and better luck than me!)

Kindly,

Thomas

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PID tuning is indeed the solution to this issue. You have to keep doing it.

When you get to within a few degrees, you will have to live with it, until the PID table gets enough entries for it to start readjusting itself. That is, it should get better over time.

(This is my understanding of how it works, I could be wrong…)