This is my second attempt at making a 3D printer.
It was designed to be a cantilever construction using MGN7 rails on the X and Y axes.
The Z axis was to be the column of a Durst M600 enlarger.
The Z axix features a built in rack and pinion drive and a torsion spring that serves to balance the mas of the print head. The column consists of a 80*4mm stainless steel plate reinforced by a 70*20 mild steel box section. This is bolted to the baseboard using a die cast aluminium fixture.
The Z axix proved reliable, though there is sone tortional play due to the friction pads having worn and the adjustment either allowing play or restricting movement sufficient to stall the Nema23 motor (5Nm).
Asa result, the Z drive was replaced by an 8mm*8 lead screw which works perfectly.
The X axis consists of two MGN 7 rails separated by 60mm mounted to a 75*37.5mm aluminium channel. There are 4 MGN7 carriages that support the Y axis, The axix is driven by the normal arrangement of 0.9 degree Nema17 motor and GT2 drive belts.
The hotend and filaament drive is a standard 0.9 degree extruder bolted directly to a cooling tower. The red plastic block mounts the Z probe. Firmware is Klipper.
The Y axis is a cantilever design using 15mm aluminium tubing and dual MGN7 rails separated by 50mm. As with all cantilever designs, there is substantial wobble at the end of the jib. Some is from the structure of the Y axis, the remainder is from the Z-X carriage that needs to be replaced by proper bearings so that the play can be removed.
Overall, despite the shortcomings, the machine prints well provided the acceleration of the carriages and gondolas is managed.
There are some significant artifacts when extrusion restarts after a retract, which, I fear, may be coming from the Klipper firmware as they are consistent at given places in the face shields I have been bulk printing.
The next upgrade will replace the Z carriage and change the Y structure to a 25mm square section which should be much stiffer. My Cubist project has shown that a 20mm square tube is sufficient for 500mm lengths if used in a gantry configuration. 25mm square should be sufficient even in a light section, though I will probably go for a medium section.
The X and Y rails are 425mm long, providing 300 and 380mm of travel respectively.
The Z axis is capable of going to 800mm+ but has been limited to 180mm by the wiring harness. Rwiring is waiting on some further products in the Shorai range.