Resume from a Power Outage?

[mmorgan11]

Is there any way to resume a print after a power outage when printing from an SD card, or is the memory completely cleared?

If the memory is cleared, does anyone have a suggestion on a UPS?

-thanks

[Eric]

No practical way to resume if the printer has lost power.

As for UPS's, before you even start looking, the questions you need to have an idea about are:

1) What peak load (NOT average load) does it need to support, in watts? Include the computer if it's attached to the printer.
2) How long a power outage do you want to survive?
3) How much are you willing to spend?
4) What's the power situation in your area?

Obviously those questions interact. Most consumers choose to limit backup-time to keep the price reasonable, but that would depend on how often you have power outages and how long they typically last.

[mmorgan11]

Ok, thanks.

I can answer most of those questions for the UPS, but I'm not sure how much power a Max v2 typically uses. I know the power supply is rated at 450 W, but I doubt the actual draw is anywhere near that??

[geolupulus]

I use a UPS for the printer only and not for the computer. I print from SD cards and use the computer w/ Repetier to monitor temps & adjust print speed mid-print. I have confirmed that losing power to the computer while printing from SD (even with Repetier connected to the printer) does not affect the printing in any way. MOST of my power outages are 5 min or less, the UPS from amazon http://amzn.com/B000Z80ICM" onclick="window.open(this.href);return false; ~$80 works for me, I get about 6.5 minutes out of it. I have a generator, but it would certainly take me more than 6.5 minutes to pull the generator out of the garage, start it, and run the extension through the window & to the UPS before it dies. I'm just playing the odds with my UPS. If you can afford it, get a bigger UPS.

[mmorgan11]

Great, that's what I needed to know. Thanks for your help!

[mhackney]

The data on the SD card is persistent, it doesn't get cleared. However, details about where the print was when the outage occurred are lost.

In the CNC machining world, you can usually find where to pick up a machining operation, say after a broken tool. But in additive manufacturing it isn't that easy since you can't track over previously laid down plastic. I've attempted to restart failed prints with some success but it is never perfect - and it requires a deep knowledge of gcode.

[JohnStack]

Well....there is something you can do...

You can output the layer # via serial or mod Octoprint to log lines in an overwrite fashion ("last line printed for x").

Also, some of the print server apps are open-source. Some of them log on the interface - so it is not a leap to get it to write the last line printed log.

I'm not deep enough into this to give you a process but I believe a few folks here can.

[jesse]

if you can log the time of the power outage and the gcode command executed at each time it's possible.

the gcode may need to be edited manually to move everything back to a restartable position.

[geolupulus]

Also, if printing ABS, your bed may have time to cool during the outage and your part will pop off the build plate, PLA probably wouldn't have this issue? I have had it happen with ABS. Happened two weeks ago and it is the reason I bought myself a UPS.

[dgriff]

I've attempted to restart failed prints with some success but it is never perfect - and it requires a deep knowledge of gcode.

I've done a restart (not from a full power outage, but from when I had a filament break and had to re-feed and re-prime the extruder). It took some careful tinkering to find the z-height of the last layer, then edit the g-code to restart at the next layer and continue. Probably only worked because I was printing PLA and layer adhesion wasn't going to be an issue.

Also managed to do it a different time, but I mis-typed a gcode command and shoved the hotend down into my print (no damage to hotend, but made a nice big melted hole in the print).

Gotta be careful