SO3 Z-axis spring alternative

discussion of design changes / improvements / suggestions
twforeman
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Re: SO3 Z-axis spring alternative

Post by twforeman » Fri Sep 18, 2015 6:15 pm

Actually the brake in the original post is applied when there is no power, so it is exactly what is needed.
Brake is spring actuated when no voltage is supplied to the unit. When current is supplied, the braking action is released.
It runs on 24VDC, so if you energized it with the S3 power supply it would engage when you turned off your machine.

If you put it on a relay and used the same relay to control your spindle you could make it disengage whenever the spindle was running.... I kind of like that idea. Not sure I like it $200 worth though.
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cvoinescu
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Re: SO3 Z-axis spring alternative

Post by cvoinescu » Fri Sep 18, 2015 8:09 pm

Better yet, put it on the ENABLE signal of the Z driver*. When the motor is energized, the brake disengages.

* Actually, with GRBL, of all the drivers -- there's only one ENABLE signal for all axes.
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twforeman
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Re: SO3 Z-axis spring alternative

Post by twforeman » Fri Sep 18, 2015 8:31 pm

Still not sure I like it $200 worth, though some googling finds other possible options for around $100.

I had a thought about adding a catch of some sort at the bottom of the Z carriage that would be released with a solenoid. When you raise the Z to the top it would hook the plate unless the solenoid was energized. Sort of like parking the heads on a hard drive.
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cvoinescu
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Re: SO3 Z-axis spring alternative

Post by cvoinescu » Sat Sep 19, 2015 12:25 am

Make it the same mechanism used in some retractable ball-point pens, or latching push-buttons -- then you can latch and unlatch the carriage simply by driving it all the way up.

I agree that the brake isn't worth the money.
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LTEPM
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Re: SO3 Z-axis spring alternative

Post by LTEPM » Fri Sep 25, 2015 12:49 pm

edwardrford wrote:All

I'm working on this - somewhere along the line there was a disconnect between the springs that I originally speced for the machine and the springs that are being delivered.

I'll have some definitive information to share by Monday afternoon and will report back here.

-Edward
Hi Edward,
Any update on the springs?

jacob32123
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Re: SO3 Z-axis spring alternative

Post by jacob32123 » Sat Oct 03, 2015 4:12 am

I don't have a Shapeoko 3, but has anyone tried one of these? http://www.robotdigg.com/product/558/Br ... tor+Nema23?

It's cheap, and the description says "when power failure, the max holding torque can reach 1N.m." That sounds like exactly what you'd want.

twforeman
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Re: SO3 Z-axis spring alternative

Post by twforeman » Sat Oct 03, 2015 7:20 pm

That looks cool. Need to find some way to power the brake so it turns off when you want it to, but still... If you hooked it up to your spindle control you could turn on the spindle and release the brake at the beginning of your program. I like it.
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RoguePirin
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Re: SO3 Z-axis spring alternative

Post by RoguePirin » Thu Oct 22, 2015 1:58 am

edwardrford wrote:All

I'm working on this - somewhere along the line there was a disconnect between the springs that I originally speced for the machine and the springs that are being delivered.

I'll have some definitive information to share by Monday afternoon and will report back here.

-Edward
Hi Edward,

What did you discover about the springs? Do you have any information to share?

Thanks.
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FabricatorCraig
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Re: SO3 Z-axis spring alternative

Post by FabricatorCraig » Fri Nov 13, 2015 4:16 am

Bump.

Edward indicated on September 18th that he'd have an update on the spring situation the following week. Not to bug, but we are now approaching 2 months since that comment.

Any info yet?
-----------------Craig The Fabricator-----------------
SO1 - (1) Red Powder-Coat & (1) Non-Painted Steel
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edwardrford
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Re: SO3 Z-axis spring alternative

Post by edwardrford » Fri Nov 13, 2015 3:12 pm

Hey All,

Classic case of fixing the problem and not closing the loop.

Summary:
1.) The combined strength of the two springs was slightly greater than the weight of z-axis assembly.
2.) Like all things manufactured, there is a tolerance on the springs +/-10%
3.) A certain amount of springs must have been in the -10% category and therefor could not support the weight of the z-assembly
4.) We figured all of this out back in September and changed the springs immediately. So if your machine has shipped after 9/9/2015, this is not an issue.
5.) If you have a set of springs that you'd like replaced, send an email into support@carbide3d.com and we'll get you sorted out.

-Edward
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
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