Resume print function for Luban - Revisited

Going through these forums it seems there is no EASY way to resume a print that failed. Regardless of the reason. Prints will fail.

Being in the CNC industry, i have always been able to restart a job from a certain “shape” or number.

I have 310 lines of print, it failed (extruder clogged) at line 230. (I can tell just by looking at the print)

Given Luban has been getting some nice updates, it would be much easier for end users like me, who cannot code (to modify the gcode), to be able to export ONLY the highlighted area being shown in the “line type” x-ray.

Everything would be set even the Z Axis

If I was able to code, I wouldn’t be here lol I’d be coding it!

It’s not too difficult. If you know it failed on Layer 230, open up the gcode in notepad. Find :LAYER:230, then search backwards for the most recent G0 command with a Z arguement. The Z argument will be the height of layer 230 in mm. ie, if you’re printing a 0.1mm layer height, it’ll be Z23.0. Keep that G0 line, and delete everything above it back to ;LAYER:0.

Open the new GCode in Luban and print without slicing.

It won’t be perfect. It probably didn’t fail right at the start of layer 230. It probably printed some of the layer before failing. So you’ll get some over extrusion in the partial layer. Figuring out how much of the partial layer was printed makes things harder, and requires more subtly in deleting.

The hard part for me is figuring out which layer it failed on. Digital calipers help, but I wish the display showed the layer AND the percentage.

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YES! not displaying the current layer X of Y is absurd.

It would be nice to see what layer is printing on the touch screen! If the new crew at snapmaker is monitoring this forum now, pass this to your software people, please!

If you’re so inclined, it appears they are accepting pull requests on the git repo. Without having read the code, I don’t expect it would be difficult to do.

They never created a git repo for the Original, and nobody has reverse engineered the update process, so I’m out of luck.

I agree. Generally, CNC machines tell you which shape is being cut.

Appreciate the write up! I’ll give this a go!

As for coding, im FAR from understanding how to write code. But i can look at it and somewhat understand what it does. If i was inclined enough, i would of added to the github already lol

I have run into this problem too. I agree with you that everyone has or will run into this. If for no other reason than if you aren’t going to waste filament at the end of a spool, you pretty much have to run to the end. But recovery is not so tough, in my experience. It DOES require editing G-code. But G-code is not very cryptic. There is a great YOUT video here: How to Resume an Unfinished/Failed 3D Print! (EASY FIX!) - YouTube that explains the process. But here’s the boil down:

  1. Determine the height of the portion of the print that completed by moving the print head to the top of the completed portion of the print. Snapmaker makes it easy to do this and read the height of the top of the completed portion of the print.
  2. Read the Z-value there.
  3. Open the G-Code and search for the Z value. Ex: “Z135.9”. If you can’t find that exact value, search for a close value “Z135.8” in this case.
  4. Once you find the closest value to where the printer stopped, delete all the G-code about that point. This includes the positioning commands as well as the start-up commands.
  5. Resave the G-Code file with a new name, like ResumePrint.gcode
  6. When resuming, begin the print with the print head ABOVE the part so that it doesn’t move through the part while returning to the correct restart position. Again, the Snapmaker does this naturally, but it warrants being aware of the position/movement of the head.

I recommend you test this function on a print that doesn’t matter. I had to do it on a production print the first time and was delighted to see how well it worked. I couldn’t even see a jink where the print had resumed which I chalk up to the Snapmaker’s excellent specs.