# OVERSHOOTING NOZZLE AT 205 Degrees

Posted by ManiPi
 OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 01:41AM Registered: 7 years ago Posts: 50
Hi Everybody...

I have done PID TUNING for nozzle and trying to take print model at 205 degrees...

Tried a lot but temperature is going upto 208 which is OVERSHOOTING... Manually calculated OVERSHOOTING values...

Shall I change PID_MAX and BANG_MAX values from MARLIN...?
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 02:12AM Registered: 7 years ago Posts: 50
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 02:50AM Registered: 11 years ago Posts: 528
re run the PID again,
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 03:27AM Registered: 7 years ago Posts: 50
Ya did it.
Got values are
Kp=25.83
Ki=1.93
Kd=86.36

These are REPETIER HOST CLASSIC values....

Nearly 5-6 degrees difference is coming. I am calling 205 degree MODEL, but its going upto 209 degrees....

Help me ....
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 03:33AM Registered: 9 years ago Posts: 483
Does the temperature stay at 209 degrees or does it drop to 205 degrees within a few minutes?

What effect is the 3 to 4 degrees having on your prints?
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 05:02AM Registered: 7 years ago Posts: 50
Within 30 seconds it drops to 205 then 204 203 then 205 and then starts to print....

Please see the image of effect.........
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 05:31AM Registered: 7 years ago Posts: 50
Ok done PID and got values nearly 1 degree difference.. that is Nozzle set for 205 but showing upto 206...

Now the problem is here...

Its dropping from 206 to 205 204 203 then coming to 205......
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 06:08AM Registered: 11 years ago Posts: 528
which hotend are you using ? sure you got the right thermistor selected, does this happen when print cooling fan kicks in, is the thermistor secure to the heater block?
that image above is that the first layer with breaks in , what kind of extruder you got and what's the hobbed bolt/gear like.
 Re: OVERSHOOTING NOZZLE AT 205 Degrees October 24, 2016 08:25AM Registered: 7 years ago Posts: 320
There are 3 values you can alter on any hot end, with patience and effort.

Two are the heater and cooling combination. If the cooler is controllable, that helps a lot (controllable extruder heater coolers do NOT plug into FAN output on a RAMPS board. Slight revision, there are now two outputs called E1 fan and E2 fan, if I remember correctly, for dual extruder printers.

The other thing you can change is the thermistor sensor.

Sensors suffer from hysteresis to a certain extent - what they report isn't the true value. You could call it "sensor lag".

[en.wikipedia.org]

If your heater is too butch for your cooling, and your sensor isn't fast enough, even an M303 isn't going to do much to get steady temperatures. Operating a printer in a draughty area isn't going to help either.

Those values are printable with, it's not like the system is massively unusuble, but I must admit, its not good waiting for a temp drop before a print begins.
Sorry, only registered users may post in this forum.