LinuxCNC

LinuxCNC is a free, open-source software suite for controlling computer numerical control (CNC) machines such as mills, lathes, routers, and plasma cutters. It provides a real-time control environment that interprets G-code and drives machine motors and actuators through a hardware abstraction layer. LinuxCNC runs primarily on Linux and historically requires a real-time kernel to achieve precise motion timing.

The project originated as EMC2, the Enhanced Machine Controller 2, and later was renamed LinuxCNC. It is released under an open-source license and maintained by a community of developers and users.

LinuxCNC interfaces with hardware through HAL, which allows software to interact with various motion controllers, I/O devices, and sensors. Supported hardware ranges from traditional parallel-port systems to modern external motion controllers and Mesa electronics cards, enabling multi-axis control with encoder feedback and limit switches. The software outputs standard CNC commands such as G-code and M-code and supports a variety of coordinate systems, work offsets, and kinematic configurations for different machine geometries.

Users interact with LinuxCNC through graphical front ends such as Axis and other user interfaces, as well as textual command interfaces. Configuration is performed via human-readable INI and HAL configuration files that describe the machine, its axes, drives, and I/O, allowing customization for different toolpaths and workflows. LinuxCNC supports multi-axis machines, typically 3-axis or more, with additional axes enabled through appropriate kinematics and hardware.

Applications include hobbyist CNC mills, commercial machine tools, educational labs, and research projects. The software emphasizes precision, repeatability, and flexibility, but requires some technical setup to integrate hardware and tune real-time performance.