Latching magnetic tool changer

fma

Don't hold your breath, as I need to re-design all my CoreXY gantry to be able to implement a tool changer

pawPrinter

@fma Ha ha - Yeah, I know how it is!!

Red Sand Robot

@pawPrinter Have you seen any issues with the magnets causing interference with the stepper motor driving the Bondtech extruder? I want to make a version of a magnetic parking extruder system on a Prusa style machine, but am concerned about the electromagnet interfering with the operation of the stepper motor.

fma

A magnet does not generate electromagnetic interference, as it is a pure static magnetic field.

It can influence a stepper motor in 2 ways:

if the stepper and the magnet move relatively of each other (Foucault currents, Faraday effect...). But you need to move them fast to have an effect!
if the static field is high enough to reduce/cancel the magnetic field of the stepper. Unless the magnet is very big and touches the stepper, it should not happen.

dc42

As @fma implies, the chances of magnets interfering with stepper drivers is very small. However, strong magnets can prevent brushless fans from working, and even weak magnets can affect a BLTouch.

Red Sand Robot

@fma @dc42 Thanks for the info! I'll probably have the Bondtech/Titan in between the electromagnet and the stepper motor just to be safe. I'm planning on using a small M3 screw, spring and printed flag with an optical endstop switch (and homing without the electromagnets on) so there shouldn't be any issues there as might happen with a BLTouch.

pawPrinter

@red-sand-robot No, I've not noticed any problems with the Bondtech being affected by the magnets (which are permanent magnets in my case, not electromagnets - I found electromagnets a bit heavy).
Interestingly, I have had one occasion when a fan didn't start up properly. I didn't think much of it at the time, because fans can be annoying, but it could have been related to the magnets as @dc42 predicts.

juan74

@pawPrinter Nice work! I'll be inspiration for me. Could you please share your config file?

psychotik2k3

@fma kinda like mmu2 but once the filament is feeded it would go into free mode or another channel

psychotik2k3

@pawPrinter do you have link about the magnets you use ?
and do you think an external counter weight can replace the spring mecanism ?

thanks