How to Resume a Failed Print Mid-Layer on the Kobra 3

Power outage, filament runout without a sensor, spaghetti — prints fail. Sometimes you can save them. Here's how to resume a print from a specific layer.

When It's Worth Trying

• Part broke free from bed (adhesion issue) → not worth it, restart
• Power cut or stopped mid-layer → worth trying
• Filament ran out mid-print → worth trying if you catch it quickly
• Clog mid-print → fix clog, then try resume

Method 1 — Orca Slicer "Cancel Object" and Re-Slice from Layer

1. Open your original .3mf or sliced project in Orca Slicer
2. Right-click object → Change Layer Height — note the failed layer number
3. Edit → Cut → Lower part — delete the lower portion
4. Re-slice the upper half
5. Modify start G-code to lift Z to failure height before starting

Modified start G-code:

G28 X Y  ; home X and Y only — NOT Z
G1 Z[failed_height + 0.2] F3000  ; move to resume height
G92 E0

Method 2 — Edit G-code Directly

1. Open the original G-code in a text editor
2. Find the layer number (search ; layer_num = X)
3. Delete everything before that layer
4. Add home and position commands at the top

Tips for Success

• Clean nozzle before resuming — any ooze will blob at resume point
• Use same filament from same spool if possible (color match)
• Print slowly for the first few resumed layers (60% speed)
• Expect a visible seam line at the resume point — unavoidable

Prevention

• Enable filament runout sensor in settings if your Kobra 3 has one
• Enable power loss recovery in the LCD menu
• Use UPS or power strip with surge protection