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arXiv · 2509.11433

A Software-Only Post-Processor for Indexed Rotary Machining on GRBL-Based CNCs

Pedro Portugal·Damian D. Venghaus·Diego Lopez
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Abstract

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.

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Pedro Portugal, Damian D. Venghaus, Diego Lopez. 2025-09-14. A Software-Only Post-Processor for Indexed Rotary Machining on GRBL-Based CNCs. https://arxiv.org/abs/2509.11433

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