W.E.T. [CAD_CAM_EDM_DRO] Re: Stereolithography machine

Hi Graham and All:
I had a some thoughts about the liquid system. Could you not
use two pieces of pvc pipe side by sidewith a small channel between
them. They would be strapped together with a piston in each driven
by a screw and motor. The one would go up after the other had been
lowered the same amount. This way one could be filled with the resin
at the start and fill the one with part layer by layer as needed.
As for a small spot size you are right and the commercial
machines take hours to build just a small part and days to build a
large part. The largest I know about has a capacity of 20" x 24" x
16 inches deep. They glue small parts together to make extra large
parts. Time was this is not a whole lot longer if longer then
machining out of solid steel. The material machined would make the
difference in time such as a alumunim part could possible be
machined from solid faster then built up of resin. The main
difference is that you can build up parts from the resin that you can
not machine. Two examples of this is two bevel gears running in a
box with only the shafts of the gears sticking out of the solid box
or a ball bearing with the balls all ready in the races when
finished.
Another way of using the power is by the way the Z-Corp
(ZCORP.COM) does it. They use HP printer heads (and it looks like
the bridge is from a printer) to jet the fluid onto the powder. They
even use different colors so they can make a part look like it has
wood grain from darker shades for the grain. One of the fluids they
use is a starch to make removable cores for expermential castings.
They also make the molds for the casting but with a different fluid.
Note: I am not a Z- Corp customer or owner I just received the
information and saw the machine at the local rep's place of business
while researching information for the local inventors group.
I hope this is clearer then mud and helps to get the gray
matter flowing.
GOD'S BLESSINGS
Bill


For the UV cured resin machines you lower the working bed then top up,
it can't be overflowing (although it can overflow oncce each time).

For laser sintering they seem to use a gantry that lays a layer of the
fine poweder and then levels it with a squeegy. It is tempting to try
with some toner and a 2W diode from ebay.

if you use a gantry system it is going to be increadibly slow you will
probably want and need quite a small spot size so for each layer it
will be necessesary to raster scan the whole area. Even if you make a
fast gantry system (say based on a plotter) it will take forever. If
you really want to make small parts I guess that would be OK.

Graham