Thermal Runaway error  

Re: Thermal Runaway error

Hi!
I've checked the e3d site so my hotend is not the latest one with screw as all chenese clones have from the begining:-). Thermister is screwed from the bottom.
So ordered sock and will mount it after it'll arrive. Temporary will use the capton tape.

My feeling that cooling system or something in printer construction should be improved.
Capton tape makes printer not such attractive as it shold be. It is like to buy a new cheap thing from Ali, unpack and start soldering, polishing and gluening.

So waiting of new parts to fix this bug. The printer have to be attractive and without seat-of-the-pants improvements.

Ilya.

Re: Thermal Runaway error

You cannot see the sock, so makes no different what colour it is Ilya 😉

Re: Thermal Runaway error

The sock will be assembled than arrived.
Used half a meter of capton tape today-temperature starts to jump after first layer! Before firmware update to xxx6 and latest there was no issues.
Might it be a PID issue?

Re: Thermal Runaway error

I wonder if the thermister is having a wobbly? I know tightening the screw a little tight can cause a false reading.

Re: Thermal Runaway error

There're no screw.

Re: Thermal Runaway error

Ilya

This is not a printer firmware error; the firmware is behaving as it is designed. It thinks there is something wrong due to overcooling of the nozzle.

Use a lower fan speed setting at lower layers. Personally I don't turn the fan on until the 4th layer when printing at 0.2mm.

Get some of those socks from the previous post or insulate the heat block with kapton tape and/or glass cloth..

Peter

You are repeating this theory of the fan over and over again in this forums. Even if you were right this was a fault as we are all using the Prusa supplied Slic3r with its official Prusa settings and can expect it to work out of the box. There is something fishy going on with the the extruder temperature control on the MK2 and tuning your part fan probably is not and should not be the solution.

EDIT:
And I am using the offical E3D socks and the extruder temperature can be all over the place sometimes on my MK2.

Re: Thermal Runaway error

You are repeating this theory of the fan over and over again in this forums. Even if you were right this was a fault as we are all using the Prusa supplied Slic3r with its official Prusa settings and can expect it to work out of the box. There is something fishy going on with the the extruder temperature control on the MK2 and tuning your part fan probably is not and should not be the solution.

EDIT:
And I am using the offical E3D socks and the extruder temperature can be all over the place sometimes on my MK2.

Simon

If you are unhappy with the advice I choose to give then you can always ignore my posts. Yes, I do tend to post consistent advise in cases where the search facility on the forums has not helped.

I try to assist those with problems rather than reading posts and being critical. However, I would suggest that if you are experiencing the same issue and don't like my advice, then you should contact support.

As it happens, yesterday I ran some tests, with the nozzle at 260 degrees, 0.25mm away from the centre of the bed. After 5 minutes, the nozzle temperature did not vary more than half a degree. The bed temperature did drop by 1.5 degrees and by the end of hte test had only recovered about 0.5 degree.

Peter

Re: Thermal Runaway error

Simon FWIW, here's my test graph:

The printer was switched on and the nozzle moved to 125,80,0.25

Point A: My calculated extruder PID applied
Point B: Part fan turned on at 100%
Point C: Extruder temp set to 245 degrees
Point D: Extruder temp set to 260 degrees

Notes:
Calculated PID values generated for 215 degrees.
Once extruder had stabilised at 260, the variance was +0.5, -0.3 degrees
The bed was only able to maintain 64 degrees once the fan was turned on (but it was a "worst case" test).
Printer is using E3D V6 Mk2 with sock.
Ambient temp is about 20 degrees. Printer is not enclosed.

I would be happy to hear your thoughts on this.

Peter

EDIT - Latest update - there may be a thermistor connector issue causing the temperatures to be reported incorrectly by the thermistor: http://help.prusa3d.com/mk2-electronics/thermal-runaway-and-temperature-drops

Re: Thermal Runaway error

Simon FWIW, here's my test graph:

The printer was switched on and the nozzle moved to 125,80,0.25

Point A: My calculated extruder PID applied
Point B: Part fan turned on at 100%
Point C: Extruder temp set to 245 degrees
Point D: Extruder temp set to 260 degrees

Notes:
Calculated PID values generated for 215 degrees.
Once extruder had stabilised at 260, the variance was +0.5, -0.3 degrees
The bed was only able to maintain 64 degrees once the fan was turned on (but it was a "worst case" test).
Printer is using E3D V6 Mk2 with sock.
Ambient temp is about 20 degrees. Printer is not enclosed.

I would be happy to hear your thoughts on this.

Peter

EDIT - Latest update - there may be a thermistor connector issue causing the temperatures to be reported incorrectly by the thermistor: http://help.prusa3d.com/mk2-electronics/thermal-runaway-and-temperature-drops

Sorry, I didn't want to sound rude. I am a bit frustrated that all the threads about the temperature fluctuations end pretty much without any conclusion.

Your graph looks pretty perfect. I see this fluctuations up to your point A on my E3D with sock too. How did you calculate your PID?

I guess the bed not being able to keep the temperature is not surprising as you said (considering it is a synthetic worst case). What is confusing though is that in the article you linked Prusa is basically confirming your advice. Your chart though suggests that your extruder can hold up to 260 degrees with 100% part fan on.

Thanks for going through the trouble to generate this data points.

I will try another PETG or ABS print today to see if the thermistor connector was the cause.

Here is a short video where I caught the extruder temperature overshooting to 230 degrees while its target temperature was set to 205. https://goo.gl/photos/hR4VauvzFA87yjsZ9

Re: Thermal Runaway error

Hi Simon

PID tuning is here: http://reprap.org/wiki/G-code#M303:_Run_PID_tuning

connect to printer (Pronterface, OctoPi etc) and send:

M303 S210 C8

If you regularly print at a temperatures other than around 210 degrees, use your average regular temp.

You will see various outputs; it is the final set of values you need. Insert them as part of the start GCode in your slicer:

M301 P24.24 I1.93 D75.95 ; set PID for extruder heater with sock


Note that the above contains my values. You can also do the same for the bed by including E-1 in the M303 command and set the PID values using M304 with the same parameters as M301.

My link to the help document - if you scroll down, you will see that there is a new section (posted yesterday evening) with a temperature graph. Josef has been working on the problem and was able to determine that the thermistor connector can work loose and cause intermittently incorrect readings.

I have only recently (4 weeks ago) upgraded my extruder to the V6 Mk2, and was very careful to ensure that the thermistor connector was places in a good position to prevent issues of this nature whilst still allowing sufficient room for the sock to be installed.

Contrary to Josef's comments with regard to the sock, I have found its use to be very beneficial.

Peter

Re: Thermal Runaway error

Contrary to Josef's comments with regard to the sock, I have found its use to be very beneficial.

Once I attempted to print above 220C, and yet needed/wanted the fan, I ran into the issue of thermal runaway. The E3D sock solved the problem for me.

Re: Thermal Runaway error

Just to confirm. I use E3D V6 on another printer with 25W heater and the sock. It can easily withstand 100% cooling fan while still keeping 280°C using only 22W of power.

Re: Thermal Runaway error

It seems I solved my temperature fluctuations by replacing the themistor connector with a soldered connection as mentioned in the article. I printed ABS at target temperature 250 deg and it stayed locked on the whole print. No part fan. The part fan was not running when I had the fluctuations either.

Re: Thermal Runaway error

Just one last post from me in this topic...

When I generated the graph on the previous page, I had the hot nozzle 0.25mm above the bed in one place for several minutes.

The bed now has a small hole in the PEI at that place. I would therefore suggest that anyone wishing to test this issue should do so with either a greater nozzle height or at a point near to the edge of the bed.

Peter

Re: Thermal Runaway error

I just had the Termal Runnaway issue. It stopped a 10 hour print (ABS) .

I see the temperature on the display fluctuating sometimes with 10 degrees in a second which is impossible in the real world. There is no issue with the plastic flow. After this print I will solder the connector wires. I did had issues before with that connector.

Re: Thermal Runaway error

I fixed the heat sensor connector on the extruder between 2 cables. So when it moves the contact does not shake.
So far so good temperature stayed constant.

Vibration and pulling of the cable when it moves to one print area apparently caused bad contacts.