Instructions to Resume / Restart a stopped print, e.g. power failure
Basic steps are:
1. Figure out where you stopped (varying degrees of precision)
2. Edit gcode to cut out what you completed and add new header
3. Restart
I know there are other examples on the web, but these are Prusa specific instructions. I was 35 hrs into a 40 hr print when power failed. Here is what I did. This assumes the head is left sitting where it was last printing (same Z at least).
1. Finding stop point.
If it wasn’t a power failure, you may find the coordinates from the LCD menu under “Move axis”. Otherwise, you will need to measure the Z height above the bed. I used a digital caliper, but you can use a ruler to get close. Now, re-slice your model with the same settings. If you forget, they are listed at the end of the gcode file. Go to the preview in slic3r and use the layer slider to go to the Z you measured.
I studied the last layer on the printer to see patterns of perimeter where there were unique jogs and fill layer directions. In slic3r I moved the layers +/- what I measured to identify the exact layer where it stopped. I knew this layer was still being printed, but I also knew that slic3r did the perimeter first, so I decided to just start with the next layer. In my case, I determined it stopped in the middle of layer 103.4. I added the layer height 0.2, so I knew I wanted to restart at layer 103.6.
You can be more clever and also determine X,Y for higher precision restart. But it can be tricky to extract the X Y from the gcode since it is typically relative movements. There are gcode visualizers online that might help. It depends how desperate you are to save the print and how exact you want it. My Z only restart worked great because it had finished the perimeters for that layer.
2. Editing Gcode.
I edited the gcode and searched for the first “Z103.6” (should be a G1 command) and cut everything before that line. Please be aware of Z hops. For example, if your layer height is 0.1 and Z hop is 0.5, then you might find the new Z value 5 layers early. You can identify this because there is usually just one move (G1) before another Z change which is smaller. Once you find the correct layer change for you new Z, you won’t find a smaller Z after it. Luckily, default settings of 0.2 layer height and 0.5 hop won’t ever create this confusion since hops are odd and layers are even.
Then I added a new header that primes the printer, homes X,Y (but not Z!), resets the coordinates, heats the nozzle and bed, and restarts.
You will need to edit lines with ### to match your situation!
M107
M115 U3.0.10 ; tell printer latest fw version ### GRAB THIS LINE from original gcode
M83 ; extruder relative mode
G21 ; set units to millimeters
G90 ; use absolute coordinates
G92 Z103.4 E0 ; reset Z height and extruder ### CHANGE THIS TO YOUR Z that completed already (this is where your nozzle stopped)
G1 Z104 F7200.000 ; Z hop ### CHANGE THIS TO YOUR Z + ~0.5mm to avoid collisions on homing
G28 X Y ; home X Y without mesh bed level
M104 S205 ; set extruder temp ### MAKE SURE THESE TEMPS ARE CORRECT FOR YOUR FILAMENT
M140 S55 ; set bed temp
M190 S55 ; wait for bed temp
M109 S205 ; wait for extruder temp
M83 ; use relative distances for extrusion
M106 S255 ; turn fan on full ### ADJUST AS NEEDED for your filament type, e.g. 0 for ABS
; This is the start of the rest of the gcode
G1 Z103.600 F7200.000
G1 E0.80000 F2100.00000
M204 S800
[...]
NOTE: if your gcode was not E relative (default), you will need to make a couple changes. If you see E value grow through file, you are not relative.
Change E0 in G92 command to last E value that you cut out before the new Z value
Remove M83 commands
3. Print
To be safe, I loaded the new code onto the SD card. If you use a print server like Octoprint, it _may_ add its own start gcode that could mess things up. Then I just selected my new file from “print from SD card” and it worked beautifully. I can’t even see the seam!
YMMV.
Re: Instructions to Resume / Restart a stopped print, e.g. power failure
Here's pics to prove it happened. 😉
Re: Instructions to Resume / Restart a stopped print, e.g. power failure
Thanks for this. Unfortunately when it resumed it was off by less than an mm in the x and y directions, but still better than completely having to redo the print.
Re: Instructions to Resume / Restart a stopped print, e.g. power failure
How does this look?
For some reason when I fed this to the printer, it started at 108z ...?!
; generated by Slic3r 1.37.2.1-prusa3d-win64 on 2018-10-29 at 19:24:56
;
; external perimeters extrusion width = 0.42mm
; perimeters extrusion width = 0.45mm
; infill extrusion width = 0.45mm
; solid infill extrusion width = 0.45mm
; top infill extrusion width = 0.42mm
; support material extrusion width = 0.35mm
; first layer extrusion width = 0.42mm
M107 ; disable fan
M115 U3.1.0 ; tell printer latest fw version
M83 ; extruder relative mode
M104 S215 ; set extruder temp
M140 S55 ; set bed temp
M190 S55 ; wait for bed temp
M109 S215 ; wait for extruder temp
M107
M115 U3.1.0 ; tell printer latest fw version
M83 ; extruder relative mode
G21 ; set units to millimeters
G90 ; use absolute coordinates
G92 Z73.2 E0 ; reset Z height and extruder ### CHANGE THIS TO YOUR Z that completed already (this is where your nozzle stopped)
G1 Z73.8 F7200.000 ; Z hop ### CHANGE THIS TO YOUR Z + ~0.5mm to avoid collisions on homing
G28 X Y ; home X Y without mesh bed level
M104 S205 ; set extruder temp ### MAKE SURE THESE TEMPS ARE CORRECT FOR YOUR FILAMENT
M140 S55 ; set bed temp
M190 S55 ; wait for bed temp
M109 S205 ; wait for extruder temp
M83 ; use relative distances for extrusion
M106 S255 ; turn fan on full ### ADJUST AS NEEDED for your filament type, e.g. 0 for ABS
; This is the start of the rest of the gcode
G1 Z73.000 F7200.000 ; lift Z
G1 X129.747 Y78.485 F7200.000 ; move to first support material point
G1 Z72.400 F7200.000 ; restore layer Z
G1 E0.80000 F2100.00000 ; unretract
G1 F3000
G1 X127.955 Y78.485 E0.03552 ; support material
G1 F5760
G1 X129.747 Y78.485 E-0.62072 ; wipe and retract
G1 E-0.17928 F2100.00000 ; retract
G1 Z73.000 F7200.000 ; lift Z
G1 X126.867 Y80.803 F7200.000 ; move to first support material point
G1 Z72.400 F7200.000 ; restore layer Z
G1 E0.80000 F2100.00000 ; unretract
G1 F3000
G1 X121.185 Y80.803 E0.11262 ; support material
G1 X120.395 Y81.254 E0.01804 ; support material
G1 X119.986 Y81.017 E0.00938 ; support material
Re: Instructions to Resume / Restart a stopped print, e.g. power failure
I could not get this to work. I hope someone chimes in.
I gave up on it.
Re: Instructions to Resume / Restart a stopped print, e.g. power failure
was your nozzle still at level of the last layer when it stopped (looks like 72.4 from remaining gcode)? When you restarted it climbed higher to 108? The G92 should reset the Z coordinate. Why did you use 73.2?
How far into the print are you, hours and %?
RE: Instructions to Resume / Restart a stopped print, e.g. power failure
i made an account only for say thanks! you are a genius, you save my 1day 17 hours print!
thanks, gracias, brigado, danke, arigató ,grazie, mercie!
RE: Instructions to Resume / Restart a stopped print, e.g. power failure
My filament jammed 22hrs into a 30hr print
Trying to find where exactly you edit the gcode to take out the part you don’t want. Can you do this in Prusa Slicr?
I can’t find the full gcode in prusa slicr. I Tried notepad++ and can’t get that to export AS a gcode.
don’t know what to do
RE: Instructions to Resume / Restart a stopped print, e.g. power failure
Do you know the Z value at which the error occurred?
notepad++ defaults to a plain old text file, which gcode is a type of.
RE: Instructions to Resume / Restart a stopped print, e.g. power failure
@jsw
Yes, I know the value, I deleted the rest. As for the “plain old text” file. It saves as a .txt.
When I save it to my SD card, my prusa doesn’t recognize it.
RE: Instructions to Resume / Restart a stopped print, e.g. power failure
I guess I'm having trouble figuring out how I'm supposed to go about completing STEP 2 above. Where/how do I go about loading the gcode so it can be edited. OR, how do I turn a .txt file into a gcode that can be read by the Prusa?
RE: Instructions to Resume / Restart a stopped print, e.g. power failure
If you save as 'whatever.gcode' that should do it and override the .txt extension. If for some reason that does not do it (yes, many apps can be quirky), either go to the file browser and rename it, or to the command prompt and rename it. Then it should be recognized when you copy it to a SD card.
You can also do the rename as part of the copy command like:
copy whatever.txt f:whatever.gcode