The cartesian printer has an completely new redesign and is now called the UltiSteel, as a homage to the brilliant 3D printer the ultimaker. But this is a bigger, tougher more modular 3D Printer. The previous design is complete, but when the final bill of materials was complete it went far over budget. I faced two options “bite the bullet” and make my excuses for the over budgeting of the printer or go back to the drawing board. I decided to go back redesign a totally new 3D printer. This new design is decent improvement over the last printer.
The xy gantry system is similar to the system used in the zortrax and ultimaker. The direct extruder has been changed to bowden type extruder. There are a number of reasons for this. Firstly and mainly the bowden extruder method is much lighter which allows better velocity and accelerations on the gantry. Since the xy build area is relatively large at 300mm square. Quicker print speeds will lead to lower print lead times. A known caveat of bowden is its difficulty to print flexible filament and the hysteresis of the filament in the teflon tube. The hysteresis can be calibrated out with fine tuned settings. The issue with the flexible filament comes down to the buckling of the filament generally in the gap between the drive gear and the teflon tube. Shortening this distance mitigates a lot of these problems. I have chosen a bowden design called the Neustruder designed by MTM to make my first attempts to use a bowden system. It is well documented on the voltivo 3d printing forums. I have back up designs such as modified direct extruders to replace the Neustruder if its performance is not satisfactory.
The chassis is made from lasercut 3mm Thick CR4 Grade steel. The lasercut plates are tabbed and slotted joined together using bolts. The use of steel sheet gives the printer tremendous strength, rigidity and mass. This helps in improving print quality by reducing resonance and flexing etc.
The z axis platform which the build platform is part of, uses 4 High Quality 12mm Diameter Linear Shaft. On the z axis plate used lmk12uu flange bearing. These are double length bearing which have a flange for mounting it the platform lasercut plate. On top of the z axis platform lasercut plate there is a heatbed mounting plate. This mounting plate is connected using a 3 point springs and bolt system. The previous printer design used a 4 point leveling system. 3 Point leveling is superior to 4 point. 3 Point fully defines a plane were a 4 over constrains the build plate. 16×4 16mm Diameter trapezoidal leadscrew actuates the linear z axis. The use of precision leadscrews will enable the machine to print at lower micron layer heights more reliably in comparison to equivalent priced 3D printers.
The xy gantry design is heavily influenced by zortrax and ultimaker 3d printers. This system allows for high speeds and acclerations due to the low mass of the gantry. To anyone reading this just google these machines and you will see this machines.
A full file with all parts, assemblies, bill of materials etc will provided on sites like github, thingiverse. Since this printer has been developed for the college. It will require manuals and extra documentation.