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How long can a print job be?  

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Glenn Bech
(@glenn-bech)
New Member
How long can a print job be?

Hi,

After a month of 3D printing I've discovered how slow, smelly and noisy (and fun!) FDM really is. I'm in the process of making arrangements with my family so that I can keep the printer. Its moving to a fire safe box in the garage. That opens the possibilities for longer, possibly multi day print jobs and of course unattended printing.

But I can't find any good sources on how long a 3D print job can be. Will the printer run (safely and accurately ) for lets say 4-5 days? A week? Longer? I'd like to do some detailed prints where I utilize a lot of the build volume if I first make the effort of building a home for it.

Thanks 🙂

Posted : 24/07/2017 2:36 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: How long can a print job be?

Theoretically, yes, the printer can probably print for 4-5 days straight.

Realistically, pretty much all of these amateur printers are safety hazards and cannot be left unattended.

And chances are you are going to leave the printer unattended at some point during those 4-5 days.

It's not safe.

Posted : 24/07/2017 5:45 pm
Koder
(@koder)
Trusted Member
Re: How long can a print job be?

I regularly leave my Mk2s to print overnight with minimal supervision - remotely checking progress with webcam at best. Mk2s seems to be properly fused and has thermal runaway protections bundled in.

Posted : 24/07/2017 6:41 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: How long can a print job be?

There's a difference between what you do and what you recommend.

Would you actually recommend leaving this printer unattended?

Do you take responsibility for your recommendations?

Posted : 24/07/2017 7:21 pm
Koder
(@koder)
Trusted Member
Re: How long can a print job be?

Would you actually recommend leaving this printer unattended?
This is not exactly consumer product. I would leave it to run unattended, yet I do have background in electronics and did some own checks while assembling it. It prints a print right now that will run another 12 hours, and I'm willing to let it print overnight. As for recommendations, I think Prusa (the company, not Josef 🙂 - unless he speaks on behalf) has final say. Yet I'm pretty sure the print farm works 24/7.

Posted : 24/07/2017 9:17 pm
Glenn Bech
(@glenn-bech)
New Member
Topic starter answered:
Re: How long can a print job be?

I'll probably re-purpose a server rack, put it in my garage, add an automatic fire extinguisher http://www.fireprotectiononline.co.uk/automatic-fire-extinguishers/ - and a smoke alarm connected to the rest of the house.

Now I feel paranoid 🙂

Posted : 24/07/2017 9:22 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: How long can a print job be?


Would you actually recommend leaving this printer unattended?
This is not exactly consumer product. I would leave it to run unattended, yet I do have background in electronics and did some own checks while assembling it. It prints a print right now that will run another 12 hours, and I'm willing to let it print overnight. As for recommendations, I think Prusa (the company, not Josef 🙂 - unless he speaks on behalf) has final say. Yet I'm pretty sure the print farm works 24/7.

I'm pretty sure the PR print farm is attended to by some sort of sterile worker bee.

Let's take an example. Hotend fan fails. That's a catastrophic failure.

Which fuse or firmware feature, from your background in electronics and personal checking, catches that failure?

Posted : 25/07/2017 6:32 pm
Vertigo
(@vertigo)
Trusted Member
Re: How long can a print job be?


Let's take an example. Hotend fan fails. That's a catastrophic failure.

Which fuse or firmware feature, from your background in electronics and personal checking, catches that failure?

How does a hotend fail? If the heating element shorts out, the fuse will blow. If the thermistor fails, it will stop immediately.
If the nozzle gets clogged, you may get one giant mess, but 255C is very far below ABS's ignition temperature.

Mind you, Im no fan of running a printer unattended, but its probably less dangerous than keeping your dryer running.

Posted : 25/07/2017 7:57 pm
Koder
(@koder)
Trusted Member
Re: How long can a print job be?

Let's take an example. Hotend fan fails. That's a catastrophic failure.

Which fuse or firmware feature, from your background in electronics and personal checking, catches that failure?
If you print with PLA, not much will happen. Your hotend will jam, extruder will grind trough filament. Print is ruined, yet nothing catches fire.

If you print with ABS or other high-temperature filament, firmware will catch MAXTEMP as soon as nozzle gets to 310'C and will perform emergency shutdown.

Posted : 25/07/2017 8:07 pm
Koder
(@koder)
Trusted Member
Re: How long can a print job be?

If the nozzle gets clogged, you may get one giant mess, but 255C is very far below ABS's ignition temperature.
Worst case scenario is probably: fan fails, but print temperature is low enough that used PID does not trigger MAXTEMP, yet high enough that radiator eventually hits ABS glass transition. Extruder assembly melts and hotend slips out. If no cable is damaged, it will continue to operate, dragging nozzle around. Extruder damaged, yet no fire hazard. Should thermistor wire be damaged, it will either immediately trigger MAXTEMP or thermal runaway protection.

Posted : 25/07/2017 8:18 pm
Vertigo
(@vertigo)
Trusted Member
Re: How long can a print job be?


Worst case scenario is probably: fan fails, but print temperature is low enough that used PID does not trigger MAXTEMP, yet high enough that radiator eventually hits ABS glass transition. Extruder assembly melts and hotend slips out.

Far fetched (ive accidentally printed with a V6 without fan, cool end doesnt get that hot. Hot enough to jam, but not too hot to touch); but ok, its a worst case hypothetical.

If no cable is damaged, it will continue to operate, dragging nozzle around. Extruder damaged, yet no fire hazard. Should thermistor wire be damaged, it will either immediately trigger MAXTEMP or thermal runaway protection.

On my previous printer, my biggest concern was the thermistor getting dislodged, causing the hotend to be heated continually. But I see at least in prusa's firmware, this is being taken in to account. Or maybe that was already in Marlin firmware, and I just wasnt aware of it. Anyway, nice to see.

Posted : 25/07/2017 11:34 pm
Koder
(@koder)
Trusted Member
Re: How long can a print job be?

Far fetched
Agreed - that's why I called it "worst case scenario".

Posted : 25/07/2017 11:44 pm
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