Dual/triple/quad extruder docking system

Hey all.

I was pointed to this forum by someone after showing them my design for a docking system.

Now this isn't the first idea by all means, more information can be found here, although I have designed this from the ground up to fit on my 2020 extrusion corexy machine.
So far I have it docking and undocking a single tool. Although the main concept is working, and it repeatable, i would say this is still in the alpha stages of design.

[youtu.be]

This shows the docking mechanism working with an e3d v6 hotend and bowden systems.
Once i replace the heatbreak that i just broke, i can continue on designing this.

Just thought I would post this here to keep track of this design, if you have any tips, pointers, or ideas, do let me know

Cheers.

Love it, Great design! What's the repeatability of the docking mechanism? Will it click back exactly? Also, do you save weight with this design over just having 2, 3 or even 4 non-docking bowden hot ends that move on a single carriage?

Hey sorry for the late reply.

The mechanism used to locate this is just 4 cone shaped points on one part and the coresponding crevices on the other part. This locks back into the exact same spot every single time. The magnets used are N52 Neodymium magnets with a holding force of 1.2kgs each. I am waiting on some parts which have a holding force of 3kgs each. This will ensure that it will always be pulled back to the plate and locked into the exact same location each time.

Weight wasn't a massive issue, what was though is the other hot ends not being used always oozing out material and rubbing on the print if it was never lined up exactly.
With the docking mechanism, you are not only saving weight, but the idle hot ends can sit there and ooze all they want, when it comes time to print, they will be picked up, primed, wiped and then start printing their colour, all without a priming tower, and without the extra filament ruining the print.

I still have a way to go, but for now, I have the locking mechanism working, and the docks working. I just need to replace my e3d hotend heatbreak and ill be able to test again.

I'm working on a dual nozzle set up at the moment, but my system utilises a secondary lifting nozzle. I'm hoping the standby temperature feature of Duet will be enough to stop oozing.

You may want to consider a detector built in to see if the new tool has been picked up. There is always a chance for a magnet to detach, and a small microswitch will stop any print failures. The software just needs to know when to expect it to be detached.

Quote
Origamib
I'm working on a dual nozzle set up at the moment, but my system utilises a secondary lifting nozzle. I'm hoping the standby temperature feature of Duet will be enough to stop oozing.

You may want to consider a detector built in to see if the new tool has been picked up. There is always a chance for a magnet to detach, and a small microswitch will stop any print failures. The software just needs to know when to expect it to be detached.

Hey Origamib,

I do want to install microswitches into the docks, although Im not sure how i would include that in my smoothie firmware as to whether it does the Gcode for the dock/undock commands or not. Any idea?

As far as I'm aware, you'll need to make a script that asks if the endstop is currently triggered or not. This script would then end when a tool change procedure is initiated, and would restart once it has ended. If the endstop is not triggered on normal print procedure (not tool change) then printing will pause and wait for assistance, or alternatively it will retry docking / undocking x number of times.

I don't know anything about scripts for Gcode, but there is a page on S3D that explains some nice tool change scripts using IF commands. https://forum.simplify3d.com/viewtopic.php?f=8&t=1959

I'm going to start looking into more scripting like this I think, it adds a lot of functionality outside of standard slicing.

Quote
Origamib
As far as I'm aware, you'll need to make a script that asks if the endstop is currently triggered or not. This script would then end when a tool change procedure is initiated, and would restart once it has ended. If the endstop is not triggered on normal print procedure (not tool change) then printing will pause and wait for assistance, or alternatively it will retry docking / undocking x number of times.

I don't know anything about scripts for Gcode, but there is a page on S3D that explains some nice tool change scripts using IF commands. https://forum.simplify3d.com/viewtopic.php?f=8&t=1959

I'm going to start looking into more scripting like this I think, it adds a lot of functionality outside of standard slicing.

S3d scripting is quite good for this, but unfortunately on a toolchange command, you only have certain parameters that are available, such as OLDTOOL and NEWTOOL, CURRENTZPOS etc.
I would more or less need to modify the smoothie firmware