The application is a compact, portable, high-precision FDM (fused-deposition modelling) 3D printer. The device is viewed as a Cartesian robot that manufactures its workpiece by melting plastic to form layers. The objective was to develop a 3D printer that can manufacture small workpieces quickly and with high precision while maintaining a low printer purchase price. The device’s installation space is 120mm x 100mm x approx. 120mm (W/D/H). Perfect harmonisation of electronics and mechanics achieves a resolution of 1,280 steps per millimetre on the X and Y-axes and up to 64,000 steps per millimetre on the Z-axis. The Merlin Mini Hotend, which was developed in-house, weighs only 4.6g and can be used with a 0.2mm diameter nozzle. The printer can process almost any commonly-used plastic filament, regardless of manufacturer.
Problem:
High-precision 3D printing requires clearance-free linear axis movements. The printer is also to be almost silent to allow easy use in offices, studios, etc. without causing a disturbance. Ball recirculation spindles are not suitable because of the noise they cause. In component selection, consideration is also to be given to low-wear operation. The high printing speeds subject the bearings and axes to very fast movements and continuous changes of direction.
The ribbon cable on the heating bed and the extruder are also constantly subjected to these movements, and therefore must be guided in a manner that involves as little load as possible.
Solution:
The use of drylin rails and bearing housings with corresponding bearing liners, allowed us to achieve clearance-free axis guidance that has no trouble handling extended, fast loads and movement and allows fast, high-precision 3D printing. The drylin system is also very low-maintenance and almost silent, allowing device use in the immediate work environment (such as on one’s desk).
igus energy chains allow gentle guidance of the ribbon cables, preventing cable breaks and minimising cable wear.
