Possible to disable or work around thermal runaway protection
I am attempting to print some wood filled pla using a python script that randomizes the extruder temperature. The variation helps to develop a grain like effect in the print. I have been able to successfully print smaller parts using this method. When I attempt to print larger pieces, they invariably fail with a preheat error message.
This is model I am attempting to make and the script I am using:
https://www.thingiverse.com/thing:2977908
https://www.thingiverse.com/thing:49276
I believe this is a result of the board shutting down the print when it has difficulty keeping up with the temperature. It assumes there is thermal runaway happening and cancels the print. I understand this is a safety feature designed to protect the extruder from melt downing and potentially cause a fire.
I have set the parameters in the script to vary the temperature between 200 and 230C. I have also set the max value of any temperature change to 5C. It still fails. When it works on smaller pieces, I am very happy with the results. It is frustrating that I am unable to finish the model since the larger pieces always fail.
Attached are the pieces I have been able to print successfully. They have been sanded, stained, and clear coated. The last coat is drying in the photos.
Is there any way to temporarily disable or work around this feature?
Re: Possible to disable or work around thermal runaway protection
You could use the temperature command that waits for the hot end to get to temp ... that way the software isn't trying to catch up.
M109 S210 ; Set target temperature for nozzle and wait for nozzle to reach target.
Re: Possible to disable or work around thermal runaway protection
Would that be the G4 pause command? I am new to this sort of thing. I imagine this would entail parsing the gcode for every temperature change and inputting that code. Would that be correct? Is there anyway to automate that action?
Thank you for your reply.
Didn't see the code you posted. Sorry. Anyway to get that added at each temperature change automatically?
Re: Possible to disable or work around thermal runaway protection
I don't have a better answer than what has already been provided. I would like to know what filament you are using. I have tried the temp change stuff with Hatchbox wood filament but could never get near the result you have achieved.
Re: Possible to disable or work around thermal runaway protection
M109 changes temp and waits for the change before proceeding. You can add a list of desired layers and temps in the change layer code.
;BEFORE_LAYER_CHANGE
G92 E0.0
{if layer_num == 50}M109 S225{endif} ; at layer 50 set nozzle temp to 225c
If using a script, just edit the script to use M109 instead of M104 ... as far as I know, Prusa is still using M109.
ps: Seems the script has some commands the Mk3 may not use, like M230: so this segment of code needs to change. You are probably safe replacing all occurances of M104 with M109.
warmingTempCommands = "M230 S0" + eol # enable wait for temp on the first change
if firstTemp == 0:
warmingTempCommands += ("M104 S%i" + eol) % noise_to_temp(0)
else:
warmingTempCommands += ("M104 S%i" + eol) % firstTemp
# The two following commands depends on the firmware:
warmingTempCommands += "M230 S1" + eol # now disable wait for temp on the first change
warmingTempCommands += "M116" + eol # wait for the temperature to reach the setting (M109 is obsolete)
f.write(warmingTempCommands)
Re: Possible to disable or work around thermal runaway protection
Nobody else has said this yet, so I will:
Please, please please, please do not try to disable or work around the thermal runaway protection.
This is an important safety feature which will shut off the heater in order to prevent a fire. For example, if a wire breaks to one of the temperature sensors.
And wires do break. Other 3D printer models which don't have thermal runaway protection can and do catch fire. This is not something to monkey around with lightly.
Others have given you good ideas for getting your desired effect without disabling safety features. So try their suggestions instead.
Re: Possible to disable or work around thermal runaway protection
Here's a modified Python script that might work better; or it may fail miserably ...
Re: Possible to disable or work around thermal runaway protection
Thank you all for your help!
The filament is tianse wood filament. I am using the variable layer height in slicer pe in combination with the temp script to get additional variation. I did run some test prints using just the temp script and there was noticeable variation in the color. Using the two in conjunction has produced the best results. I am making three of these boxes for my nephews and niece. I am hoping this can be a learning experience for them about research, trial, and error. The first box was printed with no modifications and finished with tung oil. It looks like peanut butter. I will also print a box with variable layer height and temp and finish it with tung oil. This box uses variable layer height and temp plus minwax stain. I plan to make a post in the Print Hall of Fame detailing the various boxes and what I was able to achieve when I am done.
Disabling that feature was a last resort. Not something I was really interested in doing. I have seen some of the photos of cheaper printers that have melted down. Not something I want to experience. Nor do I want to explain to the fire department why I burned my apartment complex down haha
Thank you for the script. I will give it a try tomorrow and report back.
Currently printing the Killer Rabbit of Caerbaenog to go with my Trojan Rabbit.
Re: Possible to disable or work around thermal runaway protection
I liked the smell of Tianse Wood ... and that it's carvable after printing. But it is pretty fragile, and has a few printing issues with 0.4 nozzles.
I am Groot.
I actually liked the spider webbing and left is on... looks especially cool.
Re: Possible to disable or work around thermal runaway protection
I liked the smell of Tianse Wood ... and that it's carvable after printing. But it is pretty fragile, and has a few printing issues with 0.4 nozzles.
I am Groot.
IMG_20181118.png
I actually liked the spider webbing and left is on... looks especially cool.
I attempted to run a print using your script today. The printer never started.
When I ran the script through the command prompt it gave me the following:
Traceback (most recent call last):
File "C:\Users\namil\Desktop\wood2.py", line 316, in <module>
warmingTempCommands += ("M109 S%i" + eol) % noise_to_temp(0)
NameError: name 'warmingTempCommands' is not defined
Re: Possible to disable or work around thermal runaway protection
Commented out the initial definition ... lol ... I should have seen that ... ymmv.
Re: Possible to disable or work around thermal runaway protection
I there, I'm the one who wrote the script in the first place.
A few days ago I added an option to specify a non-default g-code command to use in order to set the temperature: `--temp-command` or the shorter variant `-w`
The "official" script can be downloaded on github as usual here https://raw.githubusercontent.com/MoonCactus/gcode_postprocessors/master/wood/wood.py
So you can now use:
python ../wood.py --temp-command M109 --file mytest.gcode
The default is to use the non-blocking and much faster M104 as before, that could trigger arguable safety conditions indeed.
But this way, you could also use M133 as required by some non common firmwares. Check https://www.simplify3d.com/support/articles/3d-printing-gcode-tutorial/#M104-M109 for more.
Note: I left the explicit pause at the start (M230) but I think it is harmless when a printer does not understand it. Please tell me if it is not 😉