Is it possible to manually stop a print, shutdown the printer, and then continue the print later?  

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Posted by: @truls

I am not comfortable leaving my printer on while I am away from home. Therefore, I am wondering if it is possible to manually stop the print and shutdown the printer before I leave home, and then turn the printer on again and continue the print at some hours later.

Is this possible?

No, this is not possible. You can pause and resume printing. However, as soon as the printer is de-energized, the program run is interrupted and the nozzle and print bed cool down. As a rule, cooling also causes the print part to detach from the printing plate.
You will probably have to schedule a longer print accordingly, e.g. at the weekend.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

If you are feeling lucky (do ya? huh?) and if you have faith in the power failure recovery, you could try pulling the plug, simulating a power failure.

If all goes well, when the power comes back, it should re-heat and resume.

I have not tried this, and do not intend to, however.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

@jsw

@truls

I guess you are thinking about the "power panic" function? Info about it here: https://help.prusa3d.com/en/article/power-panic_2092

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

@jsw

I had read about this, and wondered if it could be done in a more controlled way. But since it has such a risk, I guess that is why it's only meant as a solution to a power failure.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Yes, that's what I was referring to.  However, I would not want to use it for an otherwise routine long intentional pause in a print.

Even with a stay-warm pause, there's often some visual evidence where the pause occurred.  I'm assuming that it would be worse after the reheat and resume.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

I tested the power panic accidentally the other day by switching the power switch while moving stuff next to my enclosure. Works as expected after switching it on again. You could use this to pause a print-but, as Karl-Herbert pointed out, you will most probably have issues with detached parts due to cool down and reheating of the bed. Might work with PLA on the smooth sheet since that generally keeps sticking to the bed even after cool down. Also, depending on the spot the extruder stops you will have imperfections, try to switch it of somewhere in the infill...

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Posted by: @robin

I tested the power panic accidentally the other day by switching the power switch while moving stuff next to my enclosure. Works as expected after switching it on again.

Hmmmm ... I seem to recall somewhere in TFM them saying that the power switch (probably??) would not generate a print-saving power panic.  (Am I on drugs here?)

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

@robin

As Prusa writes, powerpanic only works during/after power interruptions. After switching off the printer power supply using the switch provided for this purpose, print can no longer continue. Can be tested quite easily.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Sorry for the confusion, my enclosure has a power switch, it supplies printer PSU, lights and RasPi... I never use the switch on the PSU.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

If the extruder nozzle is in contact with the object on power-down, how does the re-powered mk3 handle making sure that the nozzle heats up again before moving it.  Otherwise any movement of the extruder assembly will yank the object off the heat bed.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

I think the extruder is very slightly removed from the object with the last bit of power. Here, somebody filmed the whole process:

(This is an old video, firmware might react differently by now)

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

@karl-herbert

Not what I found to be honest with an i3 Mk3S. I was making a cupboard support that was going to be fully out of sight [so I didnt mind small layer shifts], and I needed to stop the print for 24 hours. I switched the printer off at the mains.

The head moved away from the object towards the PSU and everything cooled down.

The next day when I switched on, it asked me if i wanted to resume printing, heated up and carried on. There was an obvious layer shifts, but not enough to affect structural integrity.

I was printing from the SD card - I Very much doubt if this would work with Octoprint.

But there is a risk of lifting off the bed (mine didn't)  and of losing the print.

However it can work - I've seen it. But it is telling that I dont make a habit of doing it.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

It would be nice if printers have the ability to pause and save a print to restore later at the user's decision and not just a power outage.  

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Posted by: @01pad

@karl-herbert

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I was printing from the SD card - I Very much doubt if this would work with Octoprint..

I tried the 'pause' feature in Octoprint but ran into the problem of the head not being raised off the last print location and the 'resume' doesn't re-pre-heat the equipment so when I 'resumed' it the head obviously pulled the print off the bed.

Maybe I could have used Octoprint 'pause' then manually lifted the head and trying to manually pre-heat the bed/extruder.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

It seems like you should be able to use custom G Code to tell it to pause, raise Z, and cool.  The use code, to heat, lower, and resume printing,  

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Also OctoPrint certainly saves the XYZ position locally on pause ie it does not rely on the printer saving it pause position.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

Ah, I Wasn't considering pausing from Octoprint, but power out by pulling the mains supply. That would pull the supply for the Pi as well, and I would be amazed if it could recover from that.

But I upgraded the firmware for my i3 Mk3s  two weeks ago, so I'll do a video of power failure recovery with  a small part.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

I said I'd put a video up, and this is it. In fact there are two. I decided to test power outage on the treefrog model,  sliced for a 0.6 nozzle at 0.48 layer height, which is what I have set up at the moment.

I'm running an i3 Mk3s, and firmware 3.9.3-3556, my third firmware update since buying the printer as a lockdown toy in April.

Earlier, using a Pi 4 to supply the same gcode, I did the same experiment, cutting the power to the printer (at the plug, not the switch), but leaving the Pi running.

No recovery proved possible: when switched back on, the Prusa started as normal, just with half a model on the bed.

So this time, printing from the SD card, at 52%, just after the front legs were attached, I pulled the plug.

Note - The nozzle had dropped to about 186 degrees when I switched power back on, so any problems that might arise from the bed reaching room temperature (shrinkage, detachment) were not shown. When I've left a model over a weekend after a power outage, there was a small but obvious layer shift.

Also, that time, when I switched back on, I was given an option whether I wanted to restart or not. This time, and 2 firmware upgrades later, I was given no option; it just got on with it, as you can see.

I am currently using up a cheap and nasty orange PLA, which snapped during the print, at about 25%. Instead of stopping the print, I did a running re-load, which resulted in some under-extrusion which you can clearly see on the video below. But this was before the test layer at 52%. There is also quite a lot of stringing on the print as 207 degrees seems to be a little hot for this filament. It doesn't even have a thermal range on the label, so this was a guess.

The video below shows a look at the completed model. 

I think the re-start in this case was a success. However, 0.45 mm layers is course enough to hide small layer shifts, so this needs repeating with a smaller layer, and a smaller nozzle.

RE: Is it possible to manually stop a print, shutdown the printer, and then continue the print later?

I was able to view these with a cut-paste.  It looks like the print successfully completed.  Congratulations.  😉