extruder stops heating mid print

hello guys ,
im having a a problem and was hoping if you could help me with it
so im new to the 3d printer world and i finished assembling a prusa i3 i have a ramos 1.4 board and using pronterface and slic3r
i finished calibration and everything and i started printing my first print (cube) it started printing perfectly then after the first couple of layers the extruder stopped heating for no reason.
i checked the connections and the thermistor and there is nothing wrong with it.
im not sure how to check the gcode but when i open slic3r the custom gcode says

start G-code
G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

End G-code
M104 S0 ; turn off temperature
G28 X0 ; home X axis
M84 ; disable motors

im hoping if someone can help me with the problem, im clueless on what to do next

Extruders don't stop heating for no reason - there must be a cause.
I assume the temp recorded in Pronterface is gradually falling?
Is the LED for the heater mosfet circuit illuminated when the temp is falling?
Can you measure 12v across the D10 terminals when the temp is falling?

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_______________________________________
Waitaki 3D Printer

Could you start a new print after a reset?

Did you accidently touch an endstop? This would stop the printer and cool everything down.
-Olaf

When the extruder stops heating, does the machine stop or just keep going as if there is nothing wrong?

Did you also check connections to the heater? If the thermistor failed you'd see an error message on the LCD (if you have one), but an open heater wire wouldn't show up at all and the thing would keep trying to print while the extruder chewed a divot into the filament.

well the printer keeps on moving like nothing is wrong and the temp goes down gradually and when the temp started to go down i got my multimeter and checks the volts and it reads 11.89v wich is almost 12v so its good and the led for the extruder is on while the temp is going down.

no i havent touched any endstops and i tried over and over and same problem

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the_digital_dentist
When the extruder stops heating, does the machine stop or just keep going as if there is nothing wrong?

Did you also check connections to the heater? If the thermistor failed you'd see an error message on the LCD (if you have one), but an open heater wire wouldn't show up at all and the thing would keep trying to print while the extruder chewed a divot into the filament.

well as i mention earlier the machine keeps moving and the connection reads almost 12v and no i dont have an lcd screen yet

It sounds like the wiring to the heater is intermittent.

i tried to change the heater wires and it didnt work im thinking the problem is from the shortage of the volts? its 11.87v when the heat starts going down so what should i do next? any suggestions ?

You can move the driver for the extruder to the empty port and also use the other hotend- MOSFet connector.
But you have to change the pin numbers in pin.h of the firmware.

I hope someone with more insight than me can explain it better.
-Olaf

Have you got the correct thermistor selected in the firmware?

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_______________________________________
Waitaki 3D Printer

i do

I'm with DD.
It sounds like the heater (or the connections to the heater).
If the heater fails, then you would expect the temperature to grop gradually (as you are seeing). If the thermistor fails, you would not expect to see a gradual response.
When resistors fail, they usually goes open circuit (like it seems to be doing here), but I have never seen one repair itself! I would check all the connections and wiring between the RAMPS board and the heater resistor. How is the resistor connected to the wiring loom? Solder or crimp?

Next weird idea is a wrong pin setting/ board choice in Marlin?!

What if, you´d wired the heatbed to the fan-output?
Or Marlin thinks it is controlling the fan and not the bed.
-Olaf

its connected with soldering

the wierd part is all 3 pins ( D10 D9 D8 ) are having a shortage in the volts they all read 11.87v when the fail happens but when i restart everything they all read a perfect 12v.

i have no clue what to do , is it a problem with the board should i change it? or perhaps the power supply , no clue really!

The voltage being low by .13v will not be a problem - that is trivial, and likely due to the load from the bed heater (which shuts off on reset). If you are seeing power on the terminals to the hot end, and it appears to stop heating, then one of two things can be going on: Either it's still hot, and the reading is wrong, or there is a fault in the heater or it's wiring.

Have you done any testing to confirm that the hot end really is cooling down? (I don't doubt you, just trying to be certain . . ). The only other thing might be to confirm that where the heater connects to the RAMPS that you don't have the insulation pushed into the connector. That could result in power on the screws, and nothing going to the heater as well.

But again, to reiterate: If you see power on the RAMPS heater terminals (even 11.87v!) and you are cooling, the problem is in the heater and it's wiring . . . Oh, and be certain to read *across* D8/D9/D10, and not to ground . . . these switch the *low* lead, and reading to ground will always show power, whether the output is actually active or not.

- Tim

Edited 2 time(s). Last edit at 06/20/2015 11:02AM by tadawson.

I still think it's the heater (and so, I think, do most trying to help).
With power off, measure the resistance across the terminals of D10. This is the value of the resistor that is your heater. It should be five ohms give or take an ohm or two (mine is closer to six). Then print your cube, and when you see the temperature dropping, remove power and quickly take the same measurement. Either it will read about the same, indicating the heater and its associated wiring is ok, or it will read much higher indicating the heater (or its wiring) is the problem. Check what Tim suggested, I have seen it many times (the insulation in the terminal).

If it's happening at the same time during the print, then it's not random. And if it's not random, I'm guessing it's heat related. The hotend has heated up and the now the things around it are hotting up too.
I would look at the connections of the resistor to the wiring. You say you soldered them. This is the one place I didn't solder (I crimped instead). Regular solder melts at about 190 degrees and the hotend will be operating at around that temperature or even higher. The heater wires should be a bit cooler, but it was a bit close for comfort for me. Depending on what insulation you have used and how the air flows around it (and at what temperature you are operating your extruder) maybe the joints are being affected.

Eric

My vote would be intermittent connection to the heater or bad heater.

I found this on my first printer and the way I found it was to heat it up then move the wires a bit and hold them and see if the temp dropped. Most likely culprit will be where the wires have a connection. Mine was where the heater had 3" of wire that then were crimped into a longer wire, the connection flexed a bit on every print and eventually failed. It was an easy fix.

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tadawson
The voltage being low by .13v will not be a problem - that is trivial, and likely due to the losd from the bed heater (which shuts off on reset). If you are seeing power on the terminals to the hot end, and it appears to stop heating, then one of two things can be going on: Either it's still hot, and the reading is wrong, or there is a fault in the heater or it's wiring.

Have you done any testing to confirm that the hot end really is cooling down? (I don't doubt you, just trying to be certain . . ). The only other thing might be to confirm that where the heater connects to the RAMPS that you don't have the insulation pushed into the connector. That could result in power on the screws, and nothing going to the heater as well.

But again, to reiterate: If you see power on the RAMPS heater terminals (even 11.87v!) and you are cooling, the problem is in the heater and it's wiring . . . Oh, and be certain to read *across* D8/D9/D10, and not to ground . . . these switch the *low* lead, and reading to ground will always show power, whether the output is actually active or not.

- Tim

well i havent done any real tests that the extruder is cooling down but im using the same thermoster for the heatbed and its working fine and when i heat the extruder manually its reading fine and the temperature doesnt drop.
and i think the insulators are good because when i test the volts i put my multimeter on the wires of the heater.
and what do you mean exactly by read *accross* and switch to low ? ( im sorry im very new to this )

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blabbersnitch
I still think it's the heater (and so, I think, do most trying to help).
With power off, measure the resistance across the terminals of D10. This is the value of the resistor that is your heater. It should be five ohms give or take an ohm or two (mine is closer to six). Then print your cube, and when you see the temperature dropping, remove power and quickly take the same measurement. Either it will read about the same, indicating the heater and its associated wiring is ok, or it will read much higher indicating the heater (or its wiring) is the problem. Check what Tim suggested, I have seen it many times (the insulation in the terminal).

If it's happening at the same time during the print, then it's not random. And if it's not random, I'm guessing it's heat related. The hotend has heated up and the now the things around it are hotting up too.
I would look at the connections of the resistor to the wiring. You say you soldered them. This is the one place I didn't solder (I crimped instead). Regular solder melts at about 190 degrees and the hotend will be operating at around that temperature or even higher. The heater wires should be a bit cooler, but it was a bit close for comfort for me. Depending on what insulation you have used and how the air flows around it (and at what temperature you are operating your extruder) maybe the joints are being affected.

Eric

well im not sure that i measured the resistance proparly but here is what i did , i turned off the heater got my multimeter set it to ohms and put it on the D10 and it read 15.3

and i changed the heater once and it doesnt seam to make a difference ( i order 2 heaters in one pack and im using these , so maybe they are broken? )
ohh and the MOSFET i didnt solder nor crimpled it i just bought the ramps board ready so im not sure what they did on it. but it doesnt seam to wiggle or move when its heated so i think its good

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white

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tadawson
The voltage being low by .13v will not be a problem - that is trivial, and likely due to the losd from the bed heater (which shuts off on reset). If you are seeing power on the terminals to the hot end, and it appears to stop heating, then one of two things can be going on: Either it's still hot, and the reading is wrong, or there is a fault in the heater or it's wiring.

Have you done any testing to confirm that the hot end really is cooling down? (I don't doubt you, just trying to be certain . . ). The only other thing might be to confirm that where the heater connects to the RAMPS that you don't have the insulation pushed into the connector. That could result in power on the screws, and nothing going to the heater as well.

But again, to reiterate: If you see power on the RAMPS heater terminals (even 11.87v!) and you are cooling, the problem is in the heater and it's wiring . . . Oh, and be certain to read *across* D8/D9/D10, and not to ground . . . these switch the *low* lead, and reading to ground will always show power, whether the output is actually active or not.

- Tim

well i havent done any real tests that the extruder is cooling down but im using the same thermoster for the heatbed and its working fine and when i heat the extruder manually its reading fine and the temperature doesnt drop.
and i think the insulators are good because when i test the volts i put my multimeter on the wires of the heater.
and what do you mean exactly by read *accross* and switch to low ? ( im sorry im very new to this )

The MOSFET is in the ground lead, not the hot, so if you are reading voltages with your meter black lead on power supply ground, you won't get a valid reading of the heater output status.

- Tim

im not putting my black lead on the power supply its in the D10 negative terminal

Very good, just being certain . . . if you see voltage between the two D10 terminals, and have no heat, it isn't the board . . .

-Tim

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tadawson
Very good, just being certain . . . if you see voltage between the two D10 terminals, and have no heat, it isn't the board . . .

-Tim

ok great im curtain it isnt the board now should i change the heater ( although i did change it recently ) ? , or do you think its a problem with the thermistor ( although the temp is falling gradually ) ? , maybe my connection is bad? ( i'll attach a picture )

Those terminations to the board look fine.
It's also interesting to see the MOSFETs have heatsinks on them, I haven't seen that before... but I digress.

15.3 ohms seems too high. I only have my i3 for comparison, but my heater is a 5.6 ohm resistor. That's 25 watts at 12V.
15 ohms generates less than 10 watts. When you measured the resistance, was it when the temperature was dropping, or was it when it was working fine? You need to do both.

What sort of heater is it? A resistor or cartradge (which mustbe a resistor anyway)? What hotend do you have? How is the heater secured and are you using any thermal paste?
How about a photo?

How is the resistor connected to the wires that go to the ramps board? These are the connections i was referring to when I asked if they were soldered or crimped (not the connections on the board). Take some photos of the wiring too.

Eric.

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blabbersnitch
Those terminations to the board look fine.

Veto!
You should never use soldered wires in a clamping connection. The solder tends to creep away under mech. pressure and results in a loose connection.

Better use ferrules or blank twisted wire ( be careful about loose strands )

OTOH, I don´t think, this is your current Problem.
15Ohm is too much, you might have a broken heater or intermittend connection.
Maybe the wires to the heater are soldered and not clamped by a ferrule?
-Olaf

Edited 1 time(s). Last edit at 06/21/2015 04:51AM by o_lampe.

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o_lampe

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blabbersnitch
Those terminations to the board look fine.

Veto!
You should never use soldered wires in a clamping connection. The solder tends to creep away under mech. pressure and results in a loose connection.

Yep! I didn't realise they were soldered (I was just looking for insulation in the terminal as Tim mentioned). I think screw terminating soldered wires is actually illegal (here in Australia anyway).

Eric

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blabbersnitch
Those terminations to the board look fine.
It's also interesting to see the MOSFETs have heatsinks on them, I haven't seen that before... but I digress.

15.3 ohms seems too high. I only have my i3 for comparison, but my heater is a 5.6 ohm resistor. That's 25 watts at 12V.
15 ohms generates less than 10 watts. When you measured the resistance, was it when the temperature was dropping, or was it when it was working fine? You need to do both.

What sort of heater is it? A resistor or cartradge (which mustbe a resistor anyway)? What hotend do you have? How is the heater secured and are you using any thermal paste?
How about a photo?

How is the resistor connected to the wires that go to the ramps board? These are the connections i was referring to when I asked if they were soldered or crimped (not the connections on the board). Take some photos of the wiring too.

Eric.

im not sure if im measuring the resistance correctly but here is what im doing im turning off the heater the put the hot lead of my multimeter to the + at the D10 and the black lead to the - D10 so thats how im measuring it ( tell me if im doing it wrong ) and im only measuring it when its off

and thats the heater im using
[www.amazon.com]

also im attaching a couple of photos of my extruder and setup
by the way guys im very grateful for your help!