More description coming soon.
This remake of the original extruder mount part #301 of my Artifex2 All Metal Duo fixes a number of problems I've encountered with the original part. It may be possible to use this design in other 3D printers also.
I have had problems printing with two different filaments since the first day I completed building this machine. In fact, I am still struggling with accurately (<0.1 mm) calibrating the distance between the two extruder hotends.
When I purchased the kit, I did not notice that one of the extruder fan wires were connected backwards (so the fan never turned on) until one extruder became hopelessly clogged with melted filament. Hours later and using newly purchased hotends, and I was still having trouble getting both hotends to be the same height from the bed.
The new design makes it easier to align the hotends, because each mount cabn be raised or lowered about 1 mm. Loading a new filament is now easy and foolproof, removing and replacing the hotend is easier, and less attention is needed to readjust the pressure exerted by the drive gear on the filament.
Previously, the left and the right extruder mounts were completely different parts (although internally they were similar). Now, there is a common back piece for both mounts. Screws, placed through small covers for both left and right mounts, securely hold the hotends in place. If necessary, the front covers can be removed (perhaps to facilitate threading the filament) without changing the extruder alignment. Also, the current arrangement allows a PTFE tube to be placed fully into the extruder prior to positioning the hotend in the mount.
75% for the common piece, 50-75% for the covers
It is only necessary to print one of each of the three pieces if you want to keep spare parts in case the mount needs to be replaced.
I have designed my own supports for the pieces, as I felt this provided a smoother surface. The supports need to be removed after printing.
The 3D part fan can be attached to the right or left covers before the covers are put into place. Avoid over-tightening - the fan will be held at the correct angle.
Attach the base to the machine with the M3x20? screw through the top hole first.
Cut a small PTFE tube no more than 50 mm to fit into the hotend. The longer the tube, the less opportunity for the filament to stray away from its path, but the more difficult it will be to insert the hotend into its place in the base piece. See photo. If tube is cut too short, the filament may not thread as easily.
Now place the hotend with tube onto the base piece. Then screw the covers into place.
The covers fit very snugly onto the base. You might actually feel it snap into place, or it might pull into place when the pieces are screwed in.
Adjust the gear pressure before the initial printing, and then again after about 30 minutes. Tighten only enough for the filament to be grabbed by the gear.
If the mounts need to be adjusted vertically, loosen all three screws and move the entire mount vertically as needed. Retighten when done.
PTFE tube needed