What is the smartrapcore's solution to prevent bed free-fall in a current cut-off situation?

Hi, is there a smart(rapcore?) solution there that is simple enough yet it prevents a free-fall of the bed in the event of a current cut-off or some other electronic failure in the printer's electronics?
I've seen on thingiverse some elastic catchers but I am not convinced by those.

I am thinking some sort of 3d-printed (at least in part) centrifugal brake (but simple enough) or a counterweight that balances the bed.

Of course the ideal solution should be a zero-backlash (well, close to) worm reducer at the Z motor(s).

Edited 2 time(s). Last edit at 05/20/2016 05:07PM by realthor.

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

I've used light springs at the base of my z smooth rods to allow a soft landing. And considerably increasing the stepper_deative_time in configuration_adv.h to around 600 seconds. Also my end gcode has a command to move the bed back down before turning off the motors.

It's a fudge but with a dual z axis belt system if the two smooth rods are fractionally misaligned the bed doesn't drop like a brick when the motors go off.

I though about a counterweight which also takes the pressure off the z motor allowing lower currents and temperatures, not that my z motor particularly struggles now.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

Again, how are Z belts being tensioned? Are they closed loops the ones the smartrapcore guys send with the kits?

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RepRap Lander concept on Concept Forge
RepRap Lander concept on RepRap Forums
My Things, mostly experimental stuff

No I'm using this axis that I remixed [www.thingiverse.com] so the belts are clipped into belt grips like on the x carriage. I clip the rear belt first with something placed under the z carriage to approximate level, then clip the front belt. After that final level is done with the bed screws.

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions

I thought about that for long time. on a smartrapcore alu, as we use in production, we get used to and it never made a problem after all.. but it's not nice solution, i agree.

The simple of all would be to just don't cut the stepper power . Let them on as we have power on . They do like this on the up! printer. It's just a firmware parameter change.

I should try one day .

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Counterweight added and working nicely. [www.thingiverse.com]

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Simon Khoury

Co-founder of [www.precisionpiezo.co.uk] Accurate, repeatable, versatile Z-Probes
Published:Inventions