The benefits of having a 3D printer with multiple extruders are numerous: you can print soluble support material for easy removal, print a combination of flexible and rigid filament, or simply print in different colors. Unfortunately, traditional multi-extruder setups have some serious drawbacks, even aside from the cost.
Usually, the extruders are all mounted next to each other on a single carriage. This increases the mass, which can cause print quality issues like shadowing. It also reduces the printable area, as each extruder needs to be able to reach the entire area. All of this means that the design becomes more and more impractical with each extruder you add, and that’s why it’s uncommon to see more than two extruders on a printer.
Over on Hackaday.io, [rolmie] has come up with a very practical (and affordable) solution to this problem. He has designed a tool changer that gives the printer the ability to switch out hot ends on the fly. The system is very similar to the tool changers we see on CNC machining centers: tools (the hotends) are stored on a rack, and a tool change in the G-code sends the carriage over to the rack to drop off the old hotend and pick up a new one.
The benefit of the design is that both the mass and volume of the carriage are kept to a minimum, while allowing you to use many different hot ends. Each hotend’s settings can be configured individually, and you can even use different models of hotend altogether (maybe one model works better for PLA, while another is better for ABS). The design is still in the prototyping stage and needs some refinement, but it’s a very promising proof of concept that seems like it could be implemented fairly easily into most 3D printer models.
Nice one.
I am interested in more information about the printer itself looks cheap and good at the same time.
From what little I can see it seems a Smartrapcore or oneof its derivatives:
https://www.thingiverse.com/thing:651117
from what I can see it looks like a Smartrapcore, or one of its derivatives:
https://www.thingiverse.com/thing:651117
A very simple CoreXY implementation, designed by myself, not recommended to others :)
Crazy. This is really Awesome! :)
Clever.
Are you purging before nozzle move? Aligning all those nozzles in Z would be a big chore. Probably the most difficult issue
One solution could be to probe with the nozzle one endstop switch after each tool change, to determine the Z offset automatically.
This is the biggest question I have. Even with the alignment pins that the head seems to be using, the position of the nozzle seems like it could have a big enough variation to cause print problems. This is why other solutions end up using fixed heads or swapping the filament at the extruder.
i was thinking about that as well but maybe there is an internal calibration happening on the software side you know like telling the printer tool 2 has an offset of X compared to tool 1 (reference) or something..
exactly
go clicking a microswitch in a corner with every tool to do a tool Z compensation before starting the print?
Take a look at the project images. It looks like it _should_ be able to calibrate itself in reference to a calibrated tip: https://hackaday.io/project/26053/gallery#7f4820f894a372c5fe4b928ca456d5cc
It’s aligned optically:
https://hackaday.io/project/26053/gallery#c3e200004790f05e346e1582b206c610
find more details here:
https://hackaday.io/project/26053-tool-switching-multi-extrusion/log/64076-nozzle-offset-calibration
Purging is on the list but not implemented yet. The silicone wiper already has a hole for it.
I imagine some malicious code could swap them all back and forth and neatly plait all your filaments
You’d need a free tool slot to do that, and anyway generally the tool change moves would be handled by firmware.
In order for that to be possible you’d need a free tool slot. In any case generally tool change moves are handled by the firmware and not in the gcode. The gcode tool change command only selects what tool to use, though you can insert custom moves before and after the tool change sequence in many slicers.
As of now, the slicer (Cura) creates the moves to change the tool as it provides more flexibilty than the firmware, eg. wait for heating up while the tool is still in the rack or do use speed settings from the slicer, or in future purging filament which requires knowledge about retraction length and speed
how do you figure? there’s only one slot per tool it seems so no place to swap them around….
Not sure if malicious code would have sufficient access, though it might be entertaining to do yourself if sufficiently bored…
Great idea and even better execution. If you could make this work with a direct extrusion system instead of the Bowden setup you’d have the holy Grail.
I was thinking about E3D Titan extruder, It is geared, so it works with very small and light motors.
Amazing. I have been talking about this for years. Now to combine it with a robotic arm like the helios or evezor and use multiple tool instead of just hot ends.
this is awesome, a laser head would be absolutely awesome, include a manipulator and the printer can even load and unload itself.
https://magnetic-tool-changer.com/ is pretty elegant compared to this. I’d like to see more prints, very few so far.
Awesome, like 3D printing was not slow enough.
:o)
Guess I just found the next feature to install on my Delta :) Nice job!
same idea, but for delta printers: https://www.youtube.com/watch?v=f60YuBrHRCA
I could see this being useful for supports, use a larger nozzle for the dissolvable filiments so they can be printed faster since they will be removed anyway.
Might be interesting to have multiple extruder sizes, allowing it to increase print speed in unimportant areas.
Equip the hot ends with quick boost heating while they’re in the rack. When the gantry comes over and plugs into a different hot end, hit it with some higher volts/amps for a short bit. Of course it’d need a monitoring system.
Nice idea but dont see locking system to actually hold hotend in stop stable.. Somehow was expecting seeing head to vibrate and move on its own while printing…
I had a magnetic lock in the beginning, but figured that it is not necessary, friction is doing a good job. I tested with acceleration of 2000 mm/s² (0.2g) up to 250mm/s..
Very nice one – you should bring it to the next Make Munich
Will this be out as a STL soon? Thingiverse maybe? I’m very interested in this system!
Hey can you please tell how tool changing software works is it in filmware or do you send g code for tool change in slicer and what exactly you use like how tool changer know which tool to place down to pick up new one what will happen if multiple tools are there like how will printer know which tool to undock in order to dock another
coupling this mecanism with piezo (on the head) may be a way to go ?