HOIISP

Compact FDM 3D Printer Employing a Circumferential Single-Motor Synchronous Dual-Drive Y-Axis Architecture

Repository: https://github.com/BasilSaeedBari-bb09892/CSY-FDM-Printer
Approved: 2026-05-11 11:33:14
Last Push: 2026-05-11T11:34:08Z

Design and Fabrication of a Compact FDM 3D Printer Employing a Circumferential Single-Motor Synchronous Dual-Drive Y-Axis Architecture Fused Deposition Modelling (FDM) 3D printers are the dominant platform for desktop additive manufacturing, yet their motion systems represent engineering trade-offs that are rarely revisited at the student or hobbyist level. The most widely deployed kinematic architecture — the bed-slinger — advances the heated bed along the Y-axis using a single belt anchored to one side of the bed carriage, leaving the opposite side of the bed unsupported and susceptible to torsional loading, racking, and geometric error at higher print speeds. The alternative, CoreXY, eliminates this problem but requires two motors, a crossed belt path, complex firmware kinematics, and precise belt tension balancing — substantially increasing cost and calibration difficulty. This project proposes and physically validates a novel Y-axis belt routing strategy designated the Circumferential Synchronous Y-axis (CSY) architecture. In the CSY design, a single continuous belt is routed circumferentially around the outer perimeter of the printer frame, looping back on itself so that both lateral sides of the bed carriage are driven simultaneously by a single stepper motor. This eliminates the torsional asymmetry inherent to the standard bed-slinger without requiring a second motor or crossed belt geometry. The project will produce a complete, functional 100 × 100 × 100 mm build-volume FDM 3D printer implementing the CSY mechanism, designed for full reproducibility using components available in the Karachi local market and the Habib University Engineering Workshop. The printer will be characterised against an equivalent single-belt bed-slinger reference machine for geometric accuracy, Y-axis parallelism under dynamic load, and print quality across a range of speeds. Successful completion demonstrates the viability of the CSY architecture as a lower-cost, mechanically superior alternative to both conventional bed-slingers and CoreXY systems for compact desktop FDM machines.

Standard cartesian FDM printers that translate the heated bed along the Y-axis — commonly called bed-slingers — anchor the drive belt to a single point on one lateral edge of the bed carriage. This creates a moment arm between the drive point and the unsupported opposite edge. Under the dynamic inertial loads of high-speed printing, this moment produces measurable torsional racking: the unsupported edge of the bed lags behind the driven edge, introducing Y-axis angular error that manifests in printed parts as layer misalignment, reduced dimensional accuracy on the Y-axis, and surface quality degradation at elevated speeds. The canonical engineering solution — using two independently driven Y-axis motors (one per side) — requires precise synchronisation, doubles the motor count and driver cost, and adds firmware complexity. CoreXY systems solve the structural problem differently but introduce their own calibration burden and cost premium. No widely documented, validated solution exists that achieves synchronous dual-side Y-axis drive from a single motor using a simple, non-crossed belt path. This project identifies, designs, and physically demonstrates such a solution: a circumferentially routed belt that couples both lateral sides of the bed to a single drive motor without crossover geometry. The specific problem being solved is: can a single-motor, circumferential belt path mechanically synchronise both sides of a moving bed platform and measurably reduce torsional racking error compared to a single-anchor belt at the 100 mm/s print speed range, within a sub-Rs 15,000 independently funded component budget?