Re: How Would You Design question

Tim what tablesaw do you have in mind? and if it will only be used
for this purpose, do you really need the whole saw vs. blade, arbor
and motor.
there are lots of sliding tables available for saws as aftermarket
and OEM. this would make a good base for the saw feed. they are
almost all good or better than .025"
unless you want very precise control of the feed, an air cylinder
with soleniods and flow control valves might work. otherwise motor
and timing belt work fine (I have seen lots of very precise
barfeeders done this way)
The crossfeed and wood holder could then be mounted to the sliding
tabletop.
One of the neatest and simplest antibacklash nuts that I have seen
uses a second brass nut spring loaded against the drive nut using 4
shoulder bolts and springs.you can sort of see it here
http://www.benchdog.com/Products/ProLift/PL1002.htm
or look at the april 2002 issue (volume 155) of Fine woodworking
router lift article.
As several before have suggested use a vaccuum to hold the wood
A riving knife or splitter after the blade would protect the cut off
piece from the blade after the cut (every saw comes with one and not
using them is one of THE leading causes of tablesaw injuries)

Oh yaa the CCED part naturally all of this is computer controlled

--- In CAD_CAM_EDM_DRO@y..., "Tim Goldstein" <timg@k...> wrote:
> 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