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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: 
28678 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 (...) (19 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 (...) (19 years ago, 3-Sep-07, to lugnet.robotics.rcx)

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