Hotend stopping in middle of print

I have a Prusa i3v, running Marlin, with a RAMPS board and G interface. I slice with slic3r and use Pronterface to run the prints.
Ive had several prints now that get started, but when i come back (sometimes hours later) the hot end is melting itself a hole in a random layer just sitting in one spot maintaining temp. The screen on the printer says 'waiting for user', but if i push that it returns to printing and I have a large burnt hole in the print. I use Pronterface to run the printer, and in the dialog area there is a new line that just says 'k'.

Is sli3r inputting 'wait for user' commands at random into the gcode? Or is it something else? Anyone know?

I doubt that it is a Slic3r issue - I have never heard of Slic3r generating a "pause" command under any circumstances, so I suggest you look elsewhere. First off, see whether the fault is consistent - does the same G code cause a pause at the same place every time? If so you can try to find the line(s) that causes the error. Measure the height of the printed part when it stopped to point you toward the Z layer in the file where it happened, and then try dry-running just that section of code.

Do you keep a pet cat (not a joke) - cats walking across a keyboard have caused strange faults on unattended computers on more than one occasion! Another source is electrical spikes. These can get into the data lines when mains equipment turns on or off in the house, especially if you have such equipment plugged into the same extension socket as the printer. If the printer allows it, print from the printer's internal file and unplug the USB cable after the print has started. Is it possible that the printer can enter a "user intervention" mode if it detects certain conditions (e.g. an erroneous "out of filament" detector has tripped)?

Dave

How would I go about 'dry running' a section of code that takes place 30 mm up (point of failure)?
I don't have any cats in the house, so I can rule that out.
I have a few other things plugged into the same outlet as the printer, but during this print they were all turned off.

Thanks for the reply.


Update: I am printing another model, and it too randomly froze, around the 42mm layer. Pressing "Pause" and then "Resume" in Pronterface fixed the problem. The 'k' appeared in the log box, but the printer did not display a 'waiting for user' message.

Edited 1 time(s). Last edit at 04/27/2015 02:23PM by PBZ.

Quote
PBZ
How would I go about 'dry running' a section of code that takes place 30 mm up?
Thanks for the reply.

Simply cut out the block of code in which you suspect the problem lay using a text editor (preferably start and end on a layer change), take the filament out of the printer, home the axis but do not heat the nozzle or bed and send your extracted code to print in exactly the same way that the original job was sent to print. The printer will then go through all the movements but will not print anything (as it has no filament). Make sure that the extracted code does not contain any temperature commands (which is unlikely that far into a print unless you have more than one extruder). If it does contain temperature changes, comment them out so that you do not cook plastic in the nozzle. If you use absolute extruder moves the first move will probably cause the extruder to whirr away at high speed unless you add a G92 EXXXX command at the start, where XXXX is the value of the first E parameter in the extracted G-code block. If your printer firmware disallows extrusion when the nozzle is cold, send a "M302" command before printing to allow cold extrusion.

Dave

I have edited the two files into new gcode files containing the fail spots. ill test them when this print gets done.
thanks

Printing via Pronterface/USB is never a good idea, especial when using Arduino/RAMPS with its slow USB-over serial interface without flow control. I suggest you upload the file to SD card and print from that. Your print speed and quality may improve too.

Edited 1 time(s). Last edit at 04/28/2015 04:31AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

This was an occasional issue but never really bothered me before because i wasnt doing 7+ hour prints. i tried both the ones that failed, in just those sections and they worked fine. Im guessing right that its something to do with an electrical spike.

I havent had any issues using Proterface/USB printing, and i have yet to have the printer do what it is supposed to when i upload code and print from the printer. Ill keep it thanks. I prefer to have some control over my prints during the print, rather than almost none though the interface.

Quote
PBZ
This was an occasional issue but never really bothered me before because i wasnt doing 7+ hour prints. i tried both the ones that failed, in just those sections and they worked fine. Im guessing right that its something to do with an electrical spike.

I havent had any issues using Proterface/USB printing, and i have yet to have the printer do what it is supposed to when i upload code and print from the printer. Ill keep it thanks. I prefer to have some control over my prints during the print, rather than almost none though the interface.

You should have just as much control when printing from SD card than when printing from USB. The controller still accepts USB commands while it is printing from SD card. In fact in some cases the host (e.g. Pronterface) will not allow you to send commands without first stopping the USB print stream, and so you have more real-time control while printing from SD, e.g. adjusting speed or extrusion rate on the fly.

Dave

Ill try printing from the card. That's another problem to fix... Ill update with what happens.

ARGHHHH!!! This is happening to me too, and I'm completely miffed! Twice in the past week I've left Johnny5(my folgertech prusa i3) printing, and come back to the extruder in some random spot in the print just sitting there. My LCD is back at its main screen, and the bed and extruder stay on. Has anyone else had any experience with this? I print from my SD card with my USB plugged into a 120 to 5V cell charger.

ARGHHHH!!!! It has happened again, as I was typing this, my wife called to tell me it's stuck. I just got my baby back up and running after a whole bunch of new bearings and fan mounts, etc. Again, a failed print. This time the display says 2 hours 40 minutes. It just stopped mid-print. My hot-end and bed are still on.

I've added a battery back up UPS, put a 60mm fan on my ramps board. All the wires have good continuity through all build ranges of motion. I'm on a new arduino and ramps(fried the 5v on the old one). This time, I was only running off of my 120 power supply, no USB. I've got a fan on my x-axis motor, which was the only one that got "hot" for me.

I'm losing my mind with this damn thing. It prints beautifully, while it is printing; which is apparently only for short periods of time...


HELP!


The I also noticed that in the middle of the print, the machine slowed to a super crawl. I'd seen it once before, but just dismissed it the same. I happened to be sitting right next to it when it slowed down exponentially. The printer was still at 100% speed, but I was able to crank it up to 400% and it seemed to take me back to normal.

Well, any help would be great. Thanks everyone!


-Dave

P.S. Anybody located in Ohio?

Random firmware crashes or board resets can be a real bitch to find. Earth or power glitches are a common cause, but so are loose connections - especially on equipment where mechanical vibrations can cause a connection to briefly disconnect every now and then. All I can suggest is to go over all the connections, replugging or tightening, and try printing from a different power outlet (with the printer the only item plugged into that outlet). Assuming that the printer can run on a single 12V supply, you could even try powering the whole printer from a car battery for a couple of prints (with no USB connected) - if it still freezes you have at least eliminated the mains & PSU as the source. Static discharges can also cause a board reset, and there is an outside possibility that the bed or extruder movement is generating a static charge somewhere. If there are other firmware releases available (older or newer), try changing to a different version in case it is a firmware bug (though there is no guarantee that alternate firmware does not have the same bug). If you can access the controller board, feel all the components after it has been printing for a while to see if any are getting overly hot and perhaps entering thermal shutdown. Give the wiring a good wobble while you are at it to see whether it freezes when you wobble a particular wire or connector.

Also do some tests running a print job with all heaters (bed and hotend) cold (obviously with no filament). If it still freezes you can eliminate switching glitches from the heater circuits as being the culprit.

Dave

Common causes of hanging mid-print:

1. Ground loops involving the PC, printer, and USB cable. Plug the PC and the printer and nothing else into into the same power distribution block. Fit a ferrite bead on the USB cable if it doesn't already have one.

2. Mains brownouts. May be fixable using diodes and/or capacitors (depending on the electronics) if the brownouts are short enough. For printers that use a mains-powered heated bed, a UPS to protect everything else may be an option. The idea is to provide enough power to keep the controller and preferably the stepper motors powered for a fraction of a second, while not allowing the heaters to drain the stored power.

3. Some firmwares on some electronics will hang if a PC attached via USB goes to sleep, or if you attach another USB device to the PC while it is printing.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

And an even better solution to ground loops is to get a Pi (with Octoprint) and power it from the same PSU that the printer itself is running from.

Quote
Mikk36
And an even better solution to ground loops is to get a Pi (with Octoprint) and power it from the same PSU that the printer itself is running from.

Or use printer electronics that includes an Ethernet port and provides a web interface, such as the Duet; then you don't need the Pi and you don't need to use the USB port at all.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

More than a year later, I'm back. Oops.
So it turned out to be a combination of things. The first was that the USB cable was failing intermittently. The second was that the air conditioner would kick on and make the entire house power level fluctuate (I didn't notice this one until moving the printer to the basement and I can hear the AC on the other side of the wall). The third was that the laptop was running a virus and was hopping in and out of running slow, which was affecting the buffer fill on the printer.

Solved two out of three problems, and took dc42's advice on printing from the SD card as well (I can't print direct from the laptop anymore anyway). I have not had it stop since! Hope this info can help someone else.

The main issues on my case was the laptop lock/unlock screen saver generate fails.
Removing this from setting and all ok!!
But i prefer to print from SD.

Anything with a fairly large motor (or other inductive load) such as aircon and big freezers cause mains glitches. If you are in a building with an elevator, they can cause enormous mains dips & spikes. The issues are twice as bad in countries with 120V mains compared with countries that have 240V mains. Spike suppression mains power blocks may help a little, but in such situations the best solution is to power all sensitive electronics from an "always on" UPS.

Dave

Quote
dmould
the best solution is to power all sensitive electronics from an "always on" UPS.

Better known as online UPS.