RE: [CAD_CAM_EDM_DRO] How Would You Design question

I would use some linear rail of some type, what ever I could get on ebay or
surplus, belt or rack and pinion drive for the long axis and lead screw
drive for the short axis. Alignment to the saw would be with a long key
that fit in the miter slot on the saw table and a couple of clamps to keep
it from moving during use. The moving table would be a metal frame with a
mdf top or maybe particle board for the top. It seems to me that you are
not moving a lot of weight here, but that you do need positional accuracy
straight movement of the carriage past the blade. It seems that movement
would not need to be more than 42 inches, 37 inches for material plus 1/2
the blade diameter. It sort of sounds like a cross between a sliding table
for the saw and an incra fence with stepper or servo drive for the fence.
For this application you might even be able to get away with tubular rails
and machined UHMW bushings on the rails. I see no reason that this would
cost more than $500 if you get creative on how you build the sliding table.

John Guenther
Sterling, Virginia

> -----Original Message-----
> From: Tim Goldstein [mailto:timg@...]
> Sent: Wednesday, April 24, 2002 12:57 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] How Would You Design question
>
>
> Been thinking about creating a specific purpose CNC machine and thought it
> would be help to see how some of you would attack the problem.
> The question
> revolves complete around the mechanical design of the equipment
> and does not
> at all consider the electrical or software from the motors to the
> computer.
>
> Here are the design parameters:
> 1) The machine will be single purpose to cut sheets of wood off of blocks
> with a maximum dimension of 3" x 4" x 37"
> 2) The resulting sheets need to be consistent in thickness over the lenght
> of the sheet + - .0025
> 3) The thinnest sheets cut will be .050" and the thickest will be .200"
> 4) The cutting motion travel will need to be in the speed range of 20 - 60
> ipm with a rapid backfeed in the 200+ ipm range.
> 5) The actual cutting equipment will be a high end table saw with
> very good
> bearings so that the spindle rigidity, run out, etc do not need to be part
> of the design discussion
> 6) The designed mechinism has to fit on and be compatable with a high
> quality table saw
> 7) The mechanical portion of the design (not including motors,
> the base saw,
> electronics, or software) should be able to be constructed for about $500
> 8) Specifying expensive components that are commonly able to be
> found in the
> surplus market to meet the cost goal of #7 is acceptable.
>
> I think that pretty well lays out the general requirements I am trying to
> meet. Look forward to the various ideas that everyone may have on how to
> accomplish this. I have some ideas in mind and it will be
> interesting to see
> if they are consistent with the group consenses.
>
> Tim
> [Denver, CO]
> http://www.KTMarketing.com/CNC.html
>
>
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