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

Posted by realthor 
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.


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.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Again, how are Z belts being tensioned? Are they closed loops the ones the smartrapcore guys send with the kits?


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.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
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 .


the Smartrap project

[smartfriendz.com]
[www.thingiverse.com]
[reprap.org]
[github.com]
doc assemblage: [reprap.org]
NEW: Forum smartfriendz: [smartraptalk.smartfriendz.com]
Counterweight added and working nicely. [www.thingiverse.com]



Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions

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