🔥 MZ Flow Temp Processor

Advanced G-code post-processor that intelligently smooths flow and adjusts temperature for superior 3D print quality and layer adhesion.

Features

• 🌊 Flow Smoothing: Uses a duration-weighted lookahead window to predict upcoming flow demand and smooth feedrate transitions
• 🌡️ Dynamic Temperature Control: Adjusts nozzle temperature ahead of actual flow changes - lookahead window is automatically sized to cover the full temperature range transition time
• ⚡ Feedrate Clamping: Prevents exceeding printer's maximum volumetric flow capability
• 📊 Real-time Visualization: Live plotting of flow and temperature profiles
• 🔗 Slicer Integration: Works as post-processing script (OrcaSlicer tested)
• ⚙️ Automatic Configuration: Reads parameters from G-code comments or config blocks
• 👀 Viewer Relaunch: Optionally relaunches slicer viewer after processing

Quick Start

Installation

Python 3 required with these packages:

• numpy
• matplotlib
• PyQt5
• psutil

Install dependencies:

Ubuntu/Debian:

sudo apt install python3-matplotlib python3-numpy python3-pyqt5 python3-psutil

Arch/Cachyos:

sudo pacman -S python-matplotlib python-numpy python-pyqt5 python-psutil

Windows:

pip install matplotlib numpy PyQt5 psutil

Basic Usage

python mz_flow_temp.py <input.gcode>

Debug Mode

By default, the script shows informational messages in terminal (if run manually). A log file is created only when an error occurs.

Enable debug logging: Create an empty file called DEBUG_ON in the script folder.

This enables verbose debug output and creates a detailed log file for troubleshooting.

OrcaSlicer Integration

1. Configure Machine G-code

Go to Printer Settings > Machine G-code and add:

• At the end of Machine start G-code: ; MZ FLOW TEMP START
• At the beginning of Machine end G-code: ; MZ FLOW TEMP END

2. Add Script Settings

In Printer Settings > Notes, add:

mz_flow_temp_sec_per_c_heating = 6
mz_flow_temp_sec_per_c_cooling = 4
mz_flow_temp_launch_viewer = true

Note: sec_per_c_heating and sec_per_c_cooling control how many seconds it takes the nozzle to change 1°C. These values also determine the lookahead window size - the script automatically looks far enough ahead to start temperature transitions in time. Larger values = slower transitions = larger lookahead window.

3. Configure Filament Settings

Set these values in your Filament profile:

• Temperature ranges (low/high)
• First layer temperature
• Maximum volumetric flow rate
• Minimum print speed

4. Add Post-processing Script

In Print process > Others > Post-processing scripts:

Linux/MacOS:

python <path to script>/mz_flow_temp.py

Windows:

1. Find Python path: where python
2. Add full command: "C:\Users\<USER>\AppData\Local\Programs\Python\Python313\python.exe" <path to script>/mz_flow_temp.py

Viewer Behavior

Important: OrcaSlicer doesn't automatically show post-processed G-code. The script can relaunch the viewer to display changes.

• ESC key: Close plot without launching viewer
• Window close/Q key: Close plot and launch viewer (if enabled)

Disable viewer: mz_flow_temp_launch_viewer = false

Required Parameters

Your G-code must include:

; nozzle_temperature_range_high = 260
; nozzle_temperature_range_low = 220
; filament_diameter = 1.75
; slow_down_min_speed = 30
; filament_max_volumetric_speed = 12
; nozzle_temperature_initial_layer = 240
; initial_layer_print_height = 0.2

Plus in printer notes:

mz_flow_temp_sec_per_c_heating = 6
mz_flow_temp_sec_per_c_cooling = 4
mz_flow_temp_launch_viewer = true

How It Works

1. Parse G-code: Extract all moves and calculate XYZ distances, move times, and per-move flow rates
2. Lookahead: For each move, compute a duration-weighted average flow over the upcoming window (sized to cover the full temp range transition). Travel moves are excluded from the average
3. Adjust Temperature: Track a smoothed temperature that ramps toward the lookahead target at the configured sec_per_c rate, starting from nozzle_temperature_range_low
4. Clamp Feedrate: Where lookahead flow exceeds what the current temperature can support, reduce feedrate proportionally - with a minimum speed floor and short-move exemption
5. Visualize: Display input flow, output flow, ideal temperature, and actual output temperature in real time
6. Save & Launch: Write M104 temperature commands and adjusted feedrates into the G-code, optionally relaunch slicer viewer

Expected Results

Temperature changes are predicted ahead of time based on upcoming flow demand, so the nozzle is already at the right temperature when it needs to be - not catching up after the fact. Feedrate is reduced when the nozzle is too cold to safely handle the requested flow, preventing over-extrusion and pressure spikes. Most effective on prints with large infill-to-perimeter transitions such as the Benchy hull line.

Exit Codes

Code	Description
0	Success
1	Incorrect usage
2	Input file not found
3	Missing EXECUTABLE_BLOCK markers
4	Missing MZ FLOW TEMP markers
5	Error parsing settings
6	Missing required parameters
7	No moves found in G-code
8	Error writing output file
9	Unhandled exception

Troubleshooting

• No plots/output: Check dependencies and verify G-code contains all required parameters and markers
• Script not running: Verify post-processing script path and Python executable permissions
• Temperature not changing enough: Your nozzle_temperature_range_high and nozzle_temperature_range_low may be too close together - widen the range in your filament profile
• Temperature reacting too slowly: Decrease sec_per_c_heating / sec_per_c_cooling values
• Temperature reacting too aggressively: Increase sec_per_c_heating / sec_per_c_cooling values
• Incorrect adjustments: Ensure filament_max_volumetric_speed is accurately calibrated for your filament - an incorrect value skews the entire flow-to-temperature mapping

License

GPL v3

Support

If this project helps you, consider supporting my work: https://ko-fi.com/yurymonzon

Author

Developed by Yury MonZon, inspired by BELAYEL Salim's original temperature controller: https://github.com/sb53systems/G-Code-Flow-Temperature-Controller