Affordable desktop CNC routers are common in education, prototyping, and makerspaces, but most lack a rotary axis, limiting fabrication of rotationally symmetric or multi-sided parts. Existing solutions often require hardware retrofits, alternative controllers, or commercial CAM software, raising cost and complexity. This work presents a software-only framework for indexed rotary machining on GRBL-based CNCs. A custom post-processor converts planar toolpaths into discrete rotary steps, executed through a browser-based interface. While not equivalent to continuous 4-axis machining, the method enables practical rotary-axis fabrication using only standard, off-the-shelf mechanics, without firmware modification. By reducing technical and financial barriers, the framework expands access to multi-axis machining in classrooms, makerspaces, and small workshops, supporting hands-on learning and rapid prototyping.
Cite
@article{arxiv.2509.11433,
title = {A Software-Only Post-Processor for Indexed Rotary Machining on GRBL-Based CNCs},
author = {Pedro Portugal and Damian D. Venghaus and Diego Lopez},
journal= {arXiv preprint arXiv:2509.11433},
year = {2026}
}
Comments
13 pages, 10 figures, Python post-processor source code and web interface included