Best practice for stopping and resuming a print?
What is the best way to pause a print for an extended period of time (several hours), and resume it with minimal layer misalignment or other issues?
For my situation, I want to power off the heat sources for the several hours I'm out of the house (the machine could remain on if needed, just cold). The printer is sitting undisturbed during the pause, in a dedicated spot, the bed and extruder are not jostled, etc.
RE: Best practice for stopping and resuming a print?
I don't think there's a "best way". You let the steel sheet cool down, you risk the model getting loose.
I for one consider the risk of letting my printers print around the clock unattended as minimal. That's what they're built to do. But I do appreciate that others may have more concerns about it, maybe it's worth looking into attaching a fire detector or at least remote monitoring with a web cam (which is what I do, all my printers have a web cam installed).
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Best practice for stopping and resuming a print?
I agree with fuchsr. It´s not a good idea to cool down the sheet and then continue the print.
I have a web cam, so I can look at my printer when I am not at home and I also have a wifi plug so I can switch power off remotely.
In the enclosure I also have a smoke detector, but only a standard device without any connectivity. I was thinking about an wifi smoke detector, so I would get a message on my phone. E.g. the shelly smoke detector
RE: Best practice for stopping and resuming a print?
I've been coming around to the 'just let it run' stance. Just fighting long-standing family paranoia of not leaving heat sources plugged in with nobody around.
My machine is in a Prusa Enclosure, so a mostly metal floored box, with nothing flammable down low for hot goo etc. to drop on. There is the heavy cardboard reel of the filament, in the enclosure, but that's mounted up high. I have a dual (ionization and photoelectric) smoke alarm mounted a foot or so above the enclosure. Short of some kind of attached extinguishing system, I can't think of anything that would significantly reduce the out-of-control fire risk; if the heated elements became an ignition source, there's really nowhere for a fire to spread.
RE: Best practice for stopping and resuming a print?
Our Prusa enclosures are equipped with smoke detectors which are connected to a mains contactor. Once it gets triggered, the power is cut off immediately. This can stop a beginning fire right away whereas sending a message can not. This is somewhat analog to a solid door versus burglar alarm. The latter sending a message "Too late. The burglar is already in the house".
RE:
The platic parts of the MK3s are mostly made out of PETG which is quite flammable. Prusa offers a UL-certified self exstinguishing PETG filament. I made a Raspberry PI case out of it. It is as easy to print as regular PETG.
As far as I know, the MK4's electronic box is made out of sheet metal. Apart from being inflammable, maybe its capable of shielding the electronics. An MK3 disturbes an old fashioned fm radio sitting nearby a lot -- even when operating on batteries and not plugged into the same power circuit.