LinuxCNC is the leading open-source CNC controller software, providing production-grade motion control for a wide range of machine tools. It transforms a standard PC running Linux into a powerful, flexible CNC controller capable of driving everything from hobby 3D printers to industrial 5-axis machining centers.

Core capabilities

Motion control

Real-time performance: Uses Linux PREEMPT_RT kernel for deterministic timing
Multi-axis support: Control up to 9 axes with synchronized motion
Advanced features: Rigid tapping, cutter radius/length compensation, lathe threading, constant surface speed, adaptive feedrate
Trajectory planning: Look-ahead motion planning for smooth, efficient toolpaths

Hardware interfaces

LinuxCNC supports an extensive range of hardware interfaces:

FPGA-based (Recommended for production)

Mesa Electronics (7i76, 7i77, 7i92, 7i93, 7C81, etc.)
PCI, PCIe, Ethernet, SPI, and parallel port interfaces

Fieldbus protocols

EtherCAT (via etherlab)
Modbus TCP/RTU
CAN bus

Legacy/Embedded

Parallel port (for simple setups)
Raspberry Pi and other ARM boards via SPI

Software architecture

HAL (Hardware Abstraction Layer): Modular component system for wiring together hardware and software
INI configuration: Text-based machine configuration
Python integration: Scripting and custom components in Python
ClassicLadder: Built-in PLC for sequential control

Use cases

CNC retrofit: Upgrade old machines with modern PC-based control
Custom machines: Build unique CNC machines with full software control
Educational: Learn CNC programming and machine control
Research: Develop new kinematics and control algorithms
Production: Run small to medium manufacturing operations

Getting started

LinuxCNC offers multiple installation paths:

Live ISO: Boot and run without installation
Debian/Ubuntu packages: Install on existing Linux systems
Build from source: For developers and custom configurations

Community & support

Active forum at forum.linuxcnc.org
IRC channel #linuxcnc on libera.chat
Extensive documentation and wiki
25+ years of development history

Limitations

Requires Linux (Windows not natively supported)
Real-time kernel recommended for best performance
HAL (Hardware Abstraction Layer) configuration requires understanding signal routing and component wiring — not intuitive for PLC-trained electricians
USB not suitable for real-time motor control

LinuxCNC

Open-source software system for computer control of mills, lathes, 3D printers, plasma cutters, and robot arms with up to 9 axes. Runs on Linux with real-time extensions for precise timing.