Subject:
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Re: the LEGO CNC-Machine
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Newsgroups:
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lugnet.robotics.rcx
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Date:
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Sat, 1 Sep 2007 14:02:58 GMT
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Viewed:
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25669 times
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In lugnet.robotics.rcx, Robert G Fay wrote:
>
> I like the worm for a drive. It provides the best ratio and the least
> backlash. It also acts as a brake while the slide is under the pressure
> returned by the cutter. Backlash invites oscillation and vibration in a
> loose drive. Real controls deal with this using tachometers to sum opposite
> dc voltage into the drive amplifier. The control says go forward and the
> tach says no. This allows high gain for that small move and control for the
> high speed move.
> This machine has worm in every axes,
>
> http://www.ozbricks.com/bobfay/newmill.htm
i see that the x axis on your machine is driven by a worm gear, over a 24t to a
16t gear to the gear rack on the bottom of the table. also, the z axis seems to
use an idler gear. that's exactly the setup i've built, you can see it here:
http://formatc1702.prul.net/gallery/v/robocnc/DSC03536.JPG.html
on top left, next to the tool changer idea (right next to the tiny word "tool").
i drew an 8t gear but i'm using a 24t now.
>
> You best
> > > design your positioning device driven from the slide and not the drive
> > > gear
> > > train.
> >
> > why is that? i am planning to use a pole reverser short-circuited on one
> > side as
> > a rotation counter
>
> Is this Lego?
yes, check out this link:
http://lego.brandls.info/legtips.htm#Rotationssensor
scroll down a bit to see how to short-circuit the pole reverser with a looped
cable. this acts like a touch sensor that opens/closes 8 times in one rotation.
out of curiosity, how long is the axle for your y-axis worm beam? because i
guess your max axle length limits the length of your axis unless you build a
more advanced setup..
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Message has 1 Reply:
 | | Re: the LEGO CNC-Machine
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| "daniel" <daniel.formatc.at.gmail.com> wrote in message news:Jnp0Cy.2CJ@lugnet.com... (...) This X axis gear box is loaded so there is no backlash. The 16T gear on the right side has a hole through it and is fixed to the shaft with a serrated half (...) (19 years ago, 1-Sep-07, to lugnet.robotics.rcx)
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Message is in Reply To:
| | Re: the LEGO CNC-Machine
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| "daniel" <daniel.formatc.at.gmail.com> wrote in message news:JnMwFu.CMs@lugnet.com... (...) I like the worm for a drive. It provides the best ratio and the least backlash. It also acts as a brake while the slide is under the pressure returned by (...) (19 years ago, 31-Aug-07, to lugnet.robotics.rcx)
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