Auto touch Z end-stop

Hi!

I made new Z end-stop.
After hot-end touches the bed - Z is stopped.
It better use with auto bed leveling in marlin firmware without any servo motors.

And works is great ! =)

[www.thingiverse.com]

I also commented this on your item but I think you should add bearings instead of a finger, over time you may introduce backlash into Z during layer changes especially if you have z-settle turned on.

Could you explain exactly what is going on here? I feel like I am missing something.

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I was confused about how this worked.

Looking on the comments on Thingiverse, the consensus seems to be that on one side of the Z (carriage), the drive nut(s) have been removed, and a secondary module has been added under the carriage, so that the existing carriage rests on the new carriage.

There seems to be a contact on the base of the original carriage and the top of the new carriage.

When the Z goes down, at some point, the nozzle touches the bed and takes the weight off the Z carriages, but the new carriage continues down, as its the original carriage has been disconnected from the threaded rod.

This causes the contact between the top of the new carriage and the underside of the main carriage to break the electrical circuit.

Just thinking a bit more about this.

The idea seems interesting, but perhaps there are better way to do it.

e.g.

Modified carriages (both sides), that have upper and lower halves, that separate when the nozzle touches the bed?

Use a strain gauge / weight sensor on the extruder?

Perhaps even use a microphone attached to the extruder (I'm not sure if this would work, as the "noise" transmitted along the rods, from the Z motors may be far more than the sound of the nozzle tapping the bed, but it may be the easiest to test)

There are probably other ways to determine if the nozzle has crashed into the bed.

BTW. I know some people were looking into using IR distance detection modules, but I don't know how they got on.
e.g.
[www.ebay.com.au]

Edited 1 time(s). Last edit at 01/10/2014 04:30PM by rogerclark.

I'm also not convinced the carriage is rigid enough to use this as a bed probe, it does make a very nice homing switch setup though.

Quote
rogerclark
I was confused about how this worked.

Looking on the comments on Thingiverse, the consensus seems to be that on one side of the Z (carriage), the drive nut(s) have been removed, and a secondary module has been added under the carriage, so that the existing carriage rests on the new carriage.

There seems to be a contact on the base of the original carriage and the top of the new carriage.

When the Z goes down, at some point, the nozzle touches the bed and takes the weight off the Z carriages, but the new carriage continues down, as its the original carriage has been disconnected from the threaded rod.

This causes the contact between the top of the new carriage and the underside of the main carriage to break the electrical circuit.

Thanks for that explanation, I get it now. It seems to me that an added benefit of a design like this is that the head can never be forced into the bed. Is the contact wired into the Z end stop trigger? If so this seems like a pretty easy design element that could be added to a lot of printers.

Radus, great job on your design.

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WWW.ZATOPA.COM - Your Place for high quality 3D Printing Filament and accessories

Quote
jzatopa
Thanks for that explanation, I get it now. It seems to me that an added benefit of a design like this is that the head can never be forced into the bed. Is the contact wired into the Z end stop trigger? If so this seems like a pretty easy design element that could be added to a lot of printers.

Radus, great job on your design.

Thanks, I'm glad you liked my thing ! =)

New video for how it work

[www.youtube.com]

Honestly this seems like the best auto Z design I have seen. It's simple, adaptable and it works. I am now planing on incorporating it into a printer I am working on.

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