Extruder mounting hardware for Taz_Mega, other OpenBuilds machines, and any other machine which can accept a metal bracket. Specifically designed to accomodate LulzBot brand Gregs/Wade extruder derivatives with Hexagon or Merlin hotends.
GitHub Repository:
Four direct-drive extruders are supported per platform. Recommended configuration is as follows.
Use of bowden extensions or half-height steppers on the last two extruders is recommended if possible.
Features include:
[] Mechanical components entirely consist of aluminum extrusion and quarter inch plate.
[] Nozzle height adjustable using shims and mounting holes.
[] Balanced airflow duct system evenly distributes airflow for part cooling to all four nozzles.
[] Outward-facing stepper motors allow tradeoffs in stepper size, cooling, and type.
[] Comprehensive BOM covering many configurations.
[] Can be hung from the middle, allowing torque-free operation with less stiff linear bearings (ie. LMxUU bearings used on existing Taz machines).
That’s going to be quite a bit of torque load on the sides of the bearing wheels and a really springy end extruder. Are you planning a counterweight off the back to balance it?
Actually, concern over torquing the X-axis bearing system is the reason this project was not designed until after the Taz_Mega was ready for testing with a Z-axis probe. Based on those experiments, I am not expecting non-linear deflection exceeding 100 microns. Still, some design precautions were taken.
Since LulzBot already uses half-height steppers in both variants of their dual-extruders, and I plan to apply active heatsinks, it should be possible to keep the weight of a full direct-drive system below 2lbs without compromising performance. My milling spindle motor is already 3lbs, with a similar center of gravity.
If that is still too much, using bowden tubes for the two outermost extruders will leave only a 1lb weight, with the center of gravity close as possible to the X-axis bearing. Balancing the extruders on both front and back of the X-axis is also a possibility, but this won’t work simultaneously with the CNC milling spindle I have. In any case, there is a good chance I will simply change the Taz_Mega’s configuration to suit specific jobs.
Finally, while the CAD model simply includes four wheels, all of the Taz_Mega carriages are built with six. Additionally, preloading can be substantially greater than normal when the gantry plate is reinforced.
EDIT: By the way, the lack of an idler latch on the Flexystruder is used to push the second extruder as close to it as possible. Again, to keep the center of gravity close as possible to the X-axis. Directly driving three extruders, runnng only the Merlin on a bowden tube, is another intended configuration. Weight would only be 1.5lbs.
What a monster! With my original taz 5 and single extruder, I have a sag due to weight of 0.1mm in the middle of the bed. That’s already challenging on big prints. . If yours is aprox. 4x the weight,you have about 0.4mm sag!
Do you tried this in reality? How do you set the nozzles, so each is exactly on same height?
Actually, if half height-steppers are used for the first two extruders, and bowden tubes for the next, the weight is about the same as a normal Taz extruder. Also, 1mm and 0.1mm metal shims are provided in the design for vertical alignment. That should be able to compensate for any approximately linear sag.
So it could be used with non-openbuilds hardware, in a variety of configurations.
Interesting… It looks very big. The issue here will be the mainly the weight. Make sure you get the blower type fans as they produce more CFM. Leveling all the printer heads will probably be a nightmare too.
Assembled. Although the Taz_Mega seems stiff enough to take the full load, the outside motors will probably be switched to half-height. Also, I have steel shim stock for vertical alignment, as well as thermal tape and a USB microscope for X/Y alignment.
