March 7, 2019
Description
This project is insprired by https://www.thingiverse.com/thing:2348263, but I think it's much simpler and puts the torsion spline the other way round: Gudo & Neotko stab the spline through the printhead, this one stabs it through the motor. My approach seems to be a bit more modular for me.
The better:
-Working with the torsion spline fixed to the motor make housing with a roof difficult, but still possible.
-Can be applied to a printer not particalary build for that (not flat top for instance)
-fits better to printers with big build areas compared to overall printer's size.
-since the skid is heavier than just a fix, less mass is moved with the carriage.
-It does not come with an own extruder drive design but is meant to give mount to your driveblock of choice. It's just to exchange the Nema17-on-the-carriange against a much lighter construction and a nema besides your housing
-With a little luck only thing you have to build on your own is the shoulder piece. Only thing with must be changed with another extruder drive is the drive holder / head piece (and with luck not even that; for instance the only difference between the titan holder and the double drive holder is the position of the filament-exit. So it's easy to construct another one.
-For whatever reason, you can change back to your former bowdenextruder within the time you need to heat your nozzle. And that's not an exaggeration, because for only have to remove 2 screws and stuff back your ptfe bowden tube.
The worse:
-you need lot of more space in one direction and a bit more into another direction (look at the photo.
-With a misplaced motor and without a spinner (not provided yet) your printer will try to drill-stab you and remove your eyes.
The ugly:
-because of the concept a double extrusion with two motors and to nozzles would stack to high and is probably not possible.
How this is meant and to mount:
Look at the 4th picture (advance to the sequence at it seems to fit against the text): A simple printhead with a bowden extruder. This is what you probably have before and what you have back after removing just two screws. The short ptfe will remain there, going through all the way to the extruder drive, giving it a well guided filament's path. (so it's still a bowden extruder, but so short, that even flexible filament will work (still unproven, but it worked with a pipe just a little shorter)).
So a piece called shoulders will hold a bearing there (10mm bore bearing, 15mm diameter, 4 or 5mm width).
From the downside, a piece called throat is pressed into that bearing. On the upper side of the throat piece is a hole for a 3mm screw for mounting with the head. When this is mounted, you have a turnable, tight connection between the shoulder part and the head (wich is the holder for your extruder drive) and the ptfe tube going all the way through. Last part is to mount the shoulder part against your carriage and we are done (last Foto).
Ready already? Well we still have the motor section here: https://www.thingiverse.com/thing:3476085.
And the mounting of the driveblock against the head-things (wich should be done before the mounting with shoulders and stuff - I changed sequence in description because of the modular concept in it).
For that, you need a 5mm bore bearing and a 5mm tube with 4mm bore, 40 to 50 mm long. The bearing is placed into the Driveblockholder (should fit tight), a brass tube is going through; onto this you mount the Gear of the driveblock usually sitting on the Nema17 axis. My brass tube fiths so tight in the bearing that there is no need for another fixation. The outer end of the brasstube needs a little hole for the connection with the coupler-piece. Wich is already forced onto that 2mmx2mm square spline.
And that's it.
Thing is still in testing. The Titan works ok (was the first try of forcing the bearing onto the brass tube and it bend a little; furthermore the concept of the titan - part of the pressing part is sort of mounted against the motor axis, and that does not work well with the brass tube. The DoubleDrive Bondtech Clone worked extremely well and smooth after I turned the Motor Gear with the wider side outward. Otherwise it fits to tight.
Have still to undergo tests with flexible material.
License:
Creative Commons - Attribution - Non-Commercial
eremit
