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 Robotics / RCX / 2917
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Subject: 
Re: the LEGO CNC-Machine
Newsgroups: 
lugnet.robotics.rcx
Date: 
Mon, 3 Sep 2007 21:27:57 GMT
Viewed: 
19609 times
  
"Bob Fay" <rgfay@earthlink.net> wrote in message
news:Jnt8MF.n84@lugnet.com...

"daniel" <daniel.formatc.at.gmail.com> wrote in message
is there any
site with tips on the geometry of the gear rack? like, how to build a
structure
that makes it mesh nicely with gears, without too much backlash but not
too
tightly? i haven't been able to figure it out... thanks!

There are several books that have some very good ideas. I have not seen
anything special on the rack drive. You have to design with the cutting
speeds in mind. You can slow down the motor, but is looses power then. Are
you going to use NQC to program your mill?

This is one of mine. Note the left worm is out if sequence by 1/4 turn with
the other two. this is putting pressure on the dual racks to remove the
backlash.
http://www.ozbricks.com/bobfay/OGSlider.jpg

This did not cure all my problems. I had to use Red Lego rubber bands on the
arms to reduce the backlash from the pins in the arms. Friction pins were
too tight.

http://www.ozbricks.com/bobfay/OGFinal1.jpg

When you get the gear ratios you want, then start looking for a way to
control that backlash.

Bob



Message has 1 Reply:
  Re: the LEGO CNC-Machine
 
the motor in the movie is called a "power motor", you can read about it here: (URL) the large black one with red axleholes. i'll be using it as the spindle. i guess the gearing in my axes is still too fast for the cutter, if i have to redesign the (...) (17 years ago, 4-Sep-07, to lugnet.robotics.rcx)

Message is in Reply To:
  Re: the LEGO CNC-Machine
 
"daniel" <daniel.formatc.at.gmail.com> wrote in message news:Jnt54J.Jpy@lugnet.com... (...) I liked the technic beams because I could lock them together. I imagine double wide bricks can make a good foundation. Put an ocassional beam in to allow (...) (17 years ago, 3-Sep-07, to lugnet.robotics.rcx)

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