Preventing Thermal Runaway Error during Nozzle Change
 
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TL
 TL
(@tl)
Active Member
Preventing Thermal Runaway Error during Nozzle Change

When changing out nozzles (specifically when tightening/removing a nozzle with a socket wrench) I'll see the nozzle temp. on the LCD screen drop ~20°C, which gives me a thermal runaway error and stops heating the nozzle mid-way through the process. Thus, I'll have to stop to reset the printer and repeat the nozzle heating process (I set it to 280°C) until I can successfully change the nozzle.

 

Not a huge nuisance, but I change nozzles enough to ask: Does anyone know of a method (either built-in or workaround) that prevents from getting this thermal runaway error and continues to heat the nozzle during temp. drops during nozzle changes? 

 

Any guidance would be appreciated!

 

Thanks!

Trent

Posted : 07/10/2020 9:31 am
herbert
(@herbert)
Trusted Member
RE: Preventing Thermal Runaway Error during Nozzle Change

would be interested too 🙂

Posted : 07/10/2020 1:00 pm
bobstro
(@bobstro)
Illustrious Member
RE: Preventing Thermal Runaway Error during Nozzle Change

I'm using a thin 16mm open wrench/spanner and haven't seen this problem. When I first screw in the new nozzle, the temp drops, but MINTEMP is not triggered. Perhaps just a thinner wrench would help? I'm using these tools. The nozzles are trash, but the tools work as well as any others I've tried. 

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Posted : 07/10/2020 3:03 pm
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karl-herbert
(@karl-herbert)
Illustrious Member
RE: Preventing Thermal Runaway Error during Nozzle Change
Posted by: @trent_land

When changing out nozzles (specifically when tightening/removing a nozzle with a socket wrench) I'll see the nozzle temp. on the LCD screen drop ~20°C, which gives me a thermal runaway error and stops heating the nozzle mid-way through the process. Thus, I'll have to stop to reset the printer and repeat the nozzle heating process (I set it to 280°C) until I can successfully change the nozzle.

 

Not a huge nuisance, but I change nozzles enough to ask: Does anyone know of a method (either built-in or workaround) that prevents from getting this thermal runaway error and continues to heat the nozzle during temp. drops during nozzle changes? 

 

Any guidance would be appreciated!

 

Thanks!

Trent

I think that the temperature is discharged too quickly when using a wrench that is too massive. For this reason I have created a heatblock holder tool made of PEEK (heat resistant up to 250 degrees C.)

This tool also works relatively well:

https://z-catch.com/product/nozzle-removal-tool/

With both tools the risk of damage of the thermistor and heating block wires is lower, because they fix the heating block on the front side.

Of course you can also use a thinner wrench.

 
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 07/10/2020 6:11 pm
TL liked
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(@)
Illustrious Member
RE: Preventing Thermal Runaway Error during Nozzle Change

Another trick is to make sure you've done the thermal calibration. It's been too long since I've done it so I don't recall the precise name: but it adjusts the aggressiveness of the heater profile to what is real vs theory. It helps to keep thermal overruns in check.

 

ps: I use an ordinary Crescent wrench (adjustable spanner). But I get in and out quickly.

This post was modified 1 year ago by --
Posted : 07/10/2020 6:21 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Preventing Thermal Runaway Error during Nozzle Change

@tim-m30

I think you are speaking about "pid calibration/tuning". I would also recommend this, both for the nozzle and for the printing bed. At least I would do it once and repeat it when changing components.

https://help.prusa3d.com/en/article/pid-tuning_2265

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 07/10/2020 6:59 pm
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herbert
(@herbert)
Trusted Member
RE: Preventing Thermal Runaway Error during Nozzle Change
Posted by: @karl-herbert

@tim-m30

I think you are speaking about "pid calibration/tuning". I would also recommend this, both for the nozzle and for the printing bed. At least I would do it once and repeat it when changing components.

https://help.prusa3d.com/en/article/pid-tuning_2265

Do I miss something? because we are in the Mini Forum and I cannot find that option on my mini 😉

Posted : 08/10/2020 11:29 am
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Preventing Thermal Runaway Error during Nozzle Change

@herbert

The Mini Firmware does not yet offer this option via the LCD menu. It is included in MK3. But this is no problem, because you can send  calibration codes via G and M command, like most control commands.
The Mini nozzle tuning works reasonably good. The bed tuning unfortunately not yet (the values were worked out manually by Prusa and entered into the firmware).
How the nozzle tuning via gcode works:

https://matterhackers.dozuki.com/Guide/PID+Tuning/6

You have to test if the determined values are saved with M500. If it cannot be saved permanently, you can also integrate the determined values into the slicer startcode (M301 Pxx.xx Ix.xx Dxx.xx).

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 08/10/2020 11:47 am
herbert liked
TL
 TL
(@tl)
Active Member
Topic starter answered:
RE: Preventing Thermal Runaway Error during Nozzle Change

@bobstro and @karl-herbert, 

 

Thanks a ton for the response and suggestions! That would make sense, considering I'm using a larger crescent wrench that truly consumes the heatblock when I'm trying to change the nozzle. And like you mentioned, I've always been worried about damaging the wires because of that as well so I went ahead and purchased the https://z-catch.com/product/nozzle-removal-tool/ so I'm looking forward to testing it out once it gets here to report back!

 

Thanks again!

Trent

Posted : 16/10/2020 12:01 am
Salvinor
(@salvinor)
New Member
RE: Preventing Thermal Runaway Error during Nozzle Change

I have the Z catch tool about a year now and yes - with this tool the temperature drops as well and the temperature alarm is triggered.

There should be a "change nozzle" option in the menu - like the "load/unload" filament options - in which the temperature failsafe is temporarily disabled.

The Z catch tool is a good buy, though.
Makes changing nozzles super easy.

Couldn't do the old method with a wrench anymore.

Posted : 22/10/2020 1:18 pm
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