A small post‑processing script that removes OrcaSlicer metadata lines the Kobra 3 Max firmware cannot parse, ensuring every sliced G‑code file uploads and prints reliably.

README.md

🛠️ Using the K3M Cleanup Script with OrcaSlicer

The Anycubic Kobra 3 Max’s stock firmware cannot parse several metadata comment lines that OrcaSlicer adds to every G‑code file.
This causes prints to fail during the “Parsing…” stage or return 500 errors.

This cleanup script automatically removes those problematic lines from every file you slice, ensuring the G‑code is fully compatible with the K3M firmware.

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1. Download one of the scripts from this Gist

• k3m-fix.ps1 — PowerShell (Windows, no Python needed)
• k3m-fix.py — Python version (Windows/Mac/Linux)

Save the script locally on your computer, for example:

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2. Add the script to OrcaSlicer

Open:

Process → Others → Post‑processing Scripts

Then enter one of the following commands depending on the script you chose.

PowerShell (Windows):

C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -ExecutionPolicy Bypass -File "C:\path\to\your\k3m-fix.ps1”

Python:

python3 “/CHANGEME/PATH/TO/k3m-fix.py”

OrcaSlicer will now run the script automatically on every G‑code file you slice, removing the incompatible lines before upload.

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3. Slice → Upload → Print

You can now slice normally.

Important Note:
When using Upload + Print, the printer will immediately begin printing.
There is no popup for:

• filament selection
• ACE mode
• confirmation dialogs

Because of this, it is recommended to use “Upload” only, then start the print manually from:

• the touchscreen, or
• the WebUI (Rinkhals / Mainsail / Fluidd)

This gives you full control over filament choice and print confirmation.

k3m-fix.ps1

param(
    [string]$Path
)

# Prefixes to remove
$BadPrefixes = @(
    "; filament_adaptive_volumetric_speed",
    "; filament_adhesiveness_category",
    "; filament_change_length",
    "; filament_colour_type",
    "; bed_temperature_formula = by_first_filament"
)

# Temp file
$Tmp = "$Path.tmp"

# Track if anything changed
$Changed = $false

# Read + write safely
$in  = [System.IO.File]::OpenText($Path)
$out = New-Object System.IO.StreamWriter($Tmp, $false, [System.Text.Encoding]::UTF8)

try {
    while (($line = $in.ReadLine()) -ne $null) {
        $trimmed = $line.TrimStart()

        $match = $false
        foreach ($prefix in $BadPrefixes) {
            if ($trimmed.StartsWith($prefix)) {
                $match = $true
                break
            }
        }

        if (-not $match) {
            $out.WriteLine($line)
        } else {
            $Changed = $true
        }
    }
}
finally {
    $in.Close()
    $out.Close()
}

# If nothing changed, delete tmp and exit
if (-not $Changed) {
    Remove-Item $Tmp -Force
    exit 0
}

# Windows-safe overwrite
Remove-Item $Path -Force
Rename-Item $Tmp $Path -Force

exit 0

k3m-fix.py

import sys
import os

# Lines to remove (prefix match)
BAD_PREFIXES = [
    "; filament_adaptive_volumetric_speed",
    "; filament_adhesiveness_category",
    "; filament_change_length",
    "; filament_colour_type",
    "; bed_temperature_formula = by_first_filament",
]

# Pre-strip prefixes for faster matching
BAD_PREFIXES = tuple(p.lstrip() for p in BAD_PREFIXES)

def should_remove(line: str) -> bool:
    stripped = line.lstrip()
    return stripped.startswith(BAD_PREFIXES)

def main():
    if len(sys.argv) < 1:
        return 0

    path = sys.argv[1]
    tmp_path = path + ".tmp"

    changed = False

    with open(path, "r", encoding="utf-8", errors="ignore") as fin, \
         open(tmp_path, "w", encoding="utf-8") as fout:

        for line in fin:
            if should_remove(line):
                changed = True
                continue
            fout.write(line)

    # If nothing changed, delete tmp and exit cleanly
    if not changed:
        os.remove(tmp_path)
        return 0

    # Windows-safe overwrite
    try:
        os.remove(path)
    except FileNotFoundError:
        pass

    os.rename(tmp_path, path)
    return 0

if __name__ == "__main__":
    main()