FoX (ZX) 45mm Axis System - Anycubic I3 Mega or any (custom printer)

thingiverse

The Anycubic I3 Mega stands out as an exceptional entry-level 3D printer. It boasts a robust mainframe, a top-notch heat bed, decent electronics, and a low acquisition price that makes it an attractive option for beginners. However, several weak points hinder the printer's performance. The hot-end assembly is notoriously unreliable, and the positioning of the heavy Bowden extruder far from the X-gantry's center plane causes issues. Additionally, the sheet metal construction of the Z-carriages is flimsy and prone to wobbling, affecting the ZX axis's geometry. A design decision that isolates the Anycubic I3 Mega from its i3 counterparts further exacerbates these problems. The 50mm X-gantry system used in this printer differs significantly from the 45mm systems employed by most other i3 printers. As users progress beyond their initial forays into 3D printing, they may feel compelled to overhaul or upgrade their Anycubic I3 Mega. Two possible courses of action are available: either invest heavily in a more advanced printer that still requires upgrades and maintenance or breathe new life into the Ai3M by transforming it into a high-performance machine. The "FoX" ZX axis design, developed specifically for users seeking this latter option, addresses many of the Ai3M's mechanical shortcomings. This modification returns the printer to its i3 roots by incorporating a 45mm X-gantry system, thus opening up a vast array of dedicated solutions. This design is an adaptation of the Ai3M 50mm FoX X-gantry system: https://www.thingiverse.com/thing:4352064 Readers interested in this project should familiarize themselves with the information provided on that page. Notable changes include: * A return to the "original Prusa" i3 large family of printers based on 45mm X-gantry systems, allowing users to employ X-carriages and extruders designed within this concept. * The design incorporates a complete ZX kinematic system, featuring a 45mm X-carriage tailored for Ai3M. This carriage is derived from the Prusa MK3 R2 X-carriage, boasting standard Prusa interface attachment points and a cable chain support. * Optional top Z axis guiding fittings (4 ball bearings 8x16x5mm required) are included to enhance printing quality. * The design incorporates minor refinements and evolution of the original 50mm FoX system. To test this design, I used one of the best direct drive extruders available in the 45mm world – the Bondtech MK2-MK3 (full kit) upgraded extruder designed for Prusa: https://www.bondtech.se/en/product/prusa-i3-mk2-mk2s-extruder-upgrade/ Some observations regarding this extruder include: * I was surprised by its weight, which approaches that of my E3D Hemera X-carriage despite its larger appearance. * After some tuning and over 25 hours of printing, the extruder proved accurate and reliable. The automatic filament loading-unloading mechanism operates smoothly and precisely, leaving me contemplating a potential upgrade to an Ai3M with Prusa's MMU (multi-material unit). * However, after another 25 hours of printing, I noted that the center of gravity for this extruder assembly is about 40mm away from the ZX axis mid-plane in a high Z position. This configuration can amplify micro-vibrations on the ZX axis, requiring perfect linear guiding and reduced X accelerations to achieve good printing quality. * The Vref was reduced to 0.69V for this extruder, but the motor runs quite hot during printing – around 60°C-70°C, nearing its maximum operational temperature of 80°C. This setup might not be suitable for an enclosed environment. FINAL EDIT: The last minor design refinements and CAD data, along with 2D drawings and high-resolution pictures, can be found in the following repository: https://github.com/Sergiu-I/AI3M---FoX-45mm-ZX-Axis/tree/CAD-models If opening a step file and saving STL models sounds unfamiliar or is too much trouble, the included models are fully tested and satisfactory.