Re: [CAD_CAM_EDM_DRO] Rack and pinion as guides and drive

In a message dated 6/15/2004 7:47:28 PM Eastern Daylight Time,
fer_mayrl@... writes:

I posted this on another group and got no answer, maybe ill get some
feedback here.
What would happen if you had a rack and pinion drive, and you just
support the gantry or bridge on the pinions, instead of using linear
guides, just use the pinions as traction wheels. some other "idlers"
should be used to prevent the bridge from moving sideways, and so it
wont rotate on its axis.
What do you guys think about this? any coments, suggestions are
welcomed.
Best regards



Fernando:

The idea you mention is exactly what many of the European manufacturers of
CNC panel saws use for the positioning "fence". This is a movable pusher that
positions the material before cutting. The rack and pinion is used to drive
that pusher and the only guide is usually either a brass screw(s) that ride
against the rack to keep the pusher in line and moving straight. However, it
is perfectly OK to allow up to 0.125" of side to side movement as the
critical measurements are the forward to backward positioning.

I guess the first question to ask is, how accurate to you want this machine
to be? If you are planning on anything more accurate that say +/- .010" I
wouldn't recommend using just the racks as guides.

Just my 2 cents worth.

Randy Abernathy
4626 Old Stilesboro Road NW
Acworth, GA 30101-4066
Phone / Fax: 770-974-5295
Cell: 678-772-4113
E-mail: Cnc002@...

I furnish technical support, repair, and other related services for your
industrial woodworking machinery. My background as Senior Service Engineer for
the SCMI Group for nearly fifteen years with factory training, combines with
my extensive background in electronics, mechanics, pneumatics, electrical and
CNC machinery to offer you needed support for your machinery.


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