FunX4 - Toolchanging 3D printer

thingiverse

This is a blog post about a custom-built 3D printer, specifically the positioning mechanism and servo-lock system used in the machine. The author has provided detailed information on the design and construction of these subsystems, including materials used, manufacturing processes, and testing results. The positioning mechanism is based on a kinematic coupling implementation, using 6mm diameter steel balls sitting in 3 pairs of 5mm diameter steel pins, epoxy-glued to machined aluminum plates. The author has achieved high repeatability of positioning accuracy, exceeding expectations. The servo-lock mechanism uses a spring-loaded T-shaped shaft, rotated by a servo motor to hold or release tools. In the locked position, the top bar of the T rests on four small steel balls. The author discusses why they chose to use precision steel balls and pins instead of printed parts, citing wear resistance and cost-effectiveness as reasons. They also mention that aluminum is used for lightweight components. A cautionary note is provided regarding the gluing process, emphasizing the importance of using two-part epoxy and avoiding excess glue. The author recommends creating notches in each 6mm hole edge to facilitate excess glue removal. The post includes links to a YouTube video demonstrating the printer's capabilities and a first-post message indicating that this is still a work-in-progress project with potential modifications ahead. Key components used in the build include: * Duet Wifi + Duex 5 boards * CoreXY configuration * Suspended Z axis * Igus bushings * MGN15 hiwin rails for Z, MGN9 hiwin rails for XY * Openbuilds C-Beams and laser-cut aluminum plates frame * Titan extruder * E3D V6 with threaded heatsink, pt100 sensors, and precision cartridges * 0.9° steppers (1.8° for Z, with a 20T/40T pulley system) * PrintBite build surface * Capricorn tubing * MKS DS450 servo * 240V heatbed with panasonic SSR * Gates belts * Shoulder screws on every pulley * Hall-effect endstops The author invites feedback and questions in the comments section, providing a link to purchase machined parts if needed.