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Printer Just Stopped in Mid Job...

Posted: Wed Jul 19, 2017 2:49 am
by Gwhite
I spent this evening trying to run my 2nd & 3rd print after doing the bracelet demo. I've got a new M2 built from a kit, and other than a few very minor oddities, the bracelet came out fine.

I bought Simplify3D, installed it, and downloaded a couple M2 accessories SLT files from Thingiverse. I tried to print them over USB, and it all started out OK, but about 2/3rds of the way through, the printer just stopped. It looked like the computer had gone to sleep, and when I woke it up, it picked up where it left off.

There were several not so minor oddities about the print quality, so I tried to run that same job but from an SD card (I have the LCD interface). I left the computer hooked up, but closed S3D. Some of the oddities were still there, but others went away, but I wanted to look something up on my computer, and woke it up again. At that point, the printer froze, and shut off the heat on both the extruder and the bed.

I eventually found that one of the macros in S3d would drop the bed down, and when it did, the print job was firmly stuck to the extruder nozzle.

I found this all a bit frustrating. I can understand it freezing if the computer decided to go to sleep in the middle of the first job, but I don't understand why waking up the computer would crash the printer.

Has anyone else seen this sort of behavior? Do I need to keep my computer awake the whole time a print job is running even when I'm not using the computer to run the job, or do I need to unplug the USB cable when I print form the SD card?


Re: Printer Just Stopped in Mid Job...

Posted: Wed Jul 19, 2017 3:44 am
by sthone
Again I can't help with the LCD as I don't own one... That said you should be able to start I job from the LCD without a computer. (I think that's the reason for it)

Anytime the computer goes to sleep or wakes up it probably is sending some kind of command (sure someone will chime in with the tech details) to the USB port to check it and this will interrupt the printer. It's best to disable the sleep feature on the computer all together while printing over USB. Even if you do disable the sleep feature printing over USB is always a crap shoot and most people just print from the SD card so there aren't any problems like that.

If you are using S3D and you do not want to leave your computer on or hooked to the printer (you have to use the "Print from SD card" feature to do this) you can start a print job and after it starts (and without closing S3D) you just yank out the USB cable from the computer. The printer will keep on running the G-code and you can then use the computer for what ever you want (or shut it off).... again it has to be printing from the SD card not from the "Begin print over USB" button.

Another option is to run the printer off of a raspberry pi using Octoprint then you don't have to worry about tying up your computer at all as everything is down over your network.

Re: Printer Just Stopped in Mid Job...

Posted: Wed Jul 19, 2017 9:20 pm
by Gwhite
I've pretty much determined that you can't do pretty much anything with the computer plugged into the USB port without a high probability of crashing a print job. I tried starting a print job from the SD card on the LCD, and foolishly decided I could disconnect Simplify3D. Nope... As soon as I hit disconnect, the print job froze.

I've resorted to unplugging the USB cable before I start printing. This will add a lot of wear & tear on the USB connector, so I've ordered a cheap A/B USB switch from Amazon so I can disconnect at the push of a button.