Pedro Portugal, Damian Venghaus, Diego Lopez | International Journal of Computer Aided Manufacturing | Vol 12, Issue 1 | ISSN: 2456-642X
Abstract
Conventional 4-axis CNC machining remains inaccessible to many due to the high costs of industrial hardware and the complexity of firmware modifications for entry-level controllers. This paper presents a software-defined framework that enables Planar-to-Rotary G-code Transformation, allowing standard 3-axis CNC systems to perform discrete 4-axis machining without hardware retrofits or firmware changes. The core of the proposed method is a custom Python-based post-processor that maps Cartesian XZ toolpaths onto a cylindrical coordinate system by injecting indexed Y-axis rotations.
The framework incorporates an automated calculation module that determines optimal angular displacement based on stock diameter and tool geometry, utilizing an 80% overlap factor to ensure surface continuity. To facilitate user adoption, the system was implemented as both a desktop GUI with 3D visualization capabilities and a platform-independent web interface. Experimental validation using hardwood and copper specimens demonstrated high dimensional fidelity, with average deviations within ±0.25 mm. By shifting the complexity from hardware to a post-processing software layer, this approach provides a cost-effective solution for indexed rotary fabrication, expanding the capabilities of desktop CNCs in educational, prototyping, and makerspace environments.
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How to cite this article
@article{PortugalP2026,
author = {Pedro Portugal and Damian Venghaus and Diego Lopez},
title = {Planar-to-Rotary G-code Transformation Via Post-Processing for Discrete 4-Axis Machining},
journal = {International Journal of Computer Aided Manufacturing},
year = {2026},
volume = {12},
number = {1},
issn = {2456-642X},
url = {https://journalspub.com/publication/ijcam/article=26082}
}