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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Sun, 2 Sep 2007 14:22:09 GMT
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Viewed:
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18760 times
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>
> This X axis gear box is loaded so there is no backlash.
by loaded, you mean it carries the workpiece and not the tool?
> The 16T gear on the
> right side has a hole through it and is fixed to the shaft with a serrated
> half bushing. This allowed me to counter rotate the gear to take up all the
> backlash including the double row of rack gearing.
ooh i see now, so that's the anti-backlash gearbox!! awesome, i would never have
thought of that. but i don't know if i will be able to integrate that mechanism
into my machine because space is already very tight. but that is a sweet idea.
>
> 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.
>
> I am not sure what your seeing on my Z axis. The four gears all engage the
> two segment worm drive and transfer motion to the dual racks on the slider.
> This is not a good design because the head is a little off center line. This
> is due to the offset of the worm thread from one side to the other side.
> Fun, but not practical.
i only meant that i'm also using the motor > worm > 24t > rack idea. however, my
z axis will not have the off-center-flaw. i haven't built it yet but i have a
very good idea of how it is going to look like.
>
> Your drawings show a lot of good planning. Try to keep your X and Y drive
> ratios the same. It will make the programming much easier if you have to
> start out with "open loops",
thanks! that's all i could do before my legos arrived :)
my x and y axes are based on identical setups, so that won't be a problem.
by open loop i'm guessing you mean no sensor feedback whatsoever? i have two
pole reversers (for x and y) and one lego rotation sensor, so at least those 3
axes should have positioning systems.
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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:Jnqvwx.p6G@lugnet.com... (...) Right! Program = x+1.005, Y-2.000, F36 (hope it makes it) i have two (...) I had forgotten that you can use a Lego Fiber Optic unit for a rotation sensor. 8 (...) (17 years ago, 2-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: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 (...) (17 years ago, 1-Sep-07, to lugnet.robotics.rcx)
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