Ultimaker loosing temperature

[somerwil 0]

Hi,

Sometimes my Ultimaker looses tempereture in the middle of a print.

I print my Netfabb gcode through RepG26 for quite some time now without this problem but since one or two weeks this problem shows up. I don't run live temperature mode in RepG so I cannot see the temperature dropping live but when the extruder stops and I stop the print I can see in Manual Mode that the temperature dropped. Basically the heater completely stopped...

Thing is that when I manually restart preheating the extruder for a new try it works again! Restarting the print after the preheating finished gives a nice startup for the print, no problem.

Then suddenly the temperature decides to drop again resulting in yet another did-not-finish...

Sometimes I can do some long printing on an evening without the problem, sometimes it already shows up on the first print. I even printed the same gcode on 1 evening three times after eachother without any modification. Temperature dropped during the first two prints while the third one was good. No point in blaming gcode.

Does anyone have a clue what my problem can be? I really tried a few things (check wiring, redo connections etc) but nothing seems to help.

Thanks,

Michael

[Daid 306]

First step would be to check if the temperature adjustment isn't in the GCode. Check for M104 and M109 commands (these set the temperature)

Second, which firmware are you running? The stock 5D firmware?

[somerwil 0]

Now that's what I call a quick answer! 2 minutes :-)

I'm on Marlin build 2 since october 2011. Did quite some good prints with it untill this problem showed up in februari.

I'm pretty sure it's not gcode related. I tried the same gcode three times to get it third time right. On the first two tries I had the temperature drop problem, third time was OK.

Can it be a temperature issue on the motherboard controller? Don't know how to check that but my motherboard fan is rather noisy which may result in bad cooling for the components on the board (?)

[ddurant 0]

Watch the LED on top of the printhead. It's not flickering, is it? If so, you've got a loose connection somewhere..

[somerwil 0]

Hi Dave,

the blue LED is fine and not flickering. Will give it another shot now to see where I end up. Checked the wiring again.

[mr_seeker 0]

Check if your heater/sensor doesnt pop out. They should be pushed well into the heating block. If it gets out of the block, it will measure the wrong temperature and fail the print.

[somerwil 0]

Last night's print finished nicely after nearly three hours of printing. I tried a different gcode for that last print which turned out fine. I'll go back to the gcode with which I had some problems and give it another try.

@mrseeker: the sensor and heater are were they should be and have nowhere to go. I checked that several times. Thinking of it it might also be a bad connection on the heater. The problem seems to occur ocassionally so perhaps vibrations and movement of the print head can cause the bad connection to come loose. I'll check that as well and maybe replace the heater.

Thanks for the replies!

[mr_seeker 0]

The newer marlin firmware give MINTEMP and MAXTEMP triggers when something goes wrong, but dont rely too much on that one actually (i managed to get a loose connection and it still kept heating).

Best is if you check the G-code, find anything thats saying M104 or M109...

[somerwil 0]

After some testing and rewiring I decided to replace my temperature sensor this week. This appeared to be the problem since I didn't have these problems since replacing it.