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

Bill,

I think commercial machines use scanning mirrors and they still take
an age to do anything, with a gantry it would take forever, literally.

I think I have seen something a little like you mention for the fluid
level, they also have to make sure the surface tenstion is broken
otherwise the level will rise but not come over the part. My memory
is a little foggy on the details to be honest.

You can put balls in bearings with the laser based stuff but the balls
need supports that are later knocked off.

> 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.

I think this would be the way to go for homebrew rapid prototyping but
it is still a serious project.

There are two ways I can see it might be done:

A: modify a printer keeping the drivers as they are but changing the
mechanics to produce a gantry printer. You might have to hijack the
step and direction pulses for the paper feed but I am sure it could be
done. Then print the layers generated from CAD as bmps to the powder.
Dump more powder with an auger on the gantry and squeegy to level
after lowering the base. Repeat.

There will have to be much messing to prevent the printer from going
crazy when it tries to feed in the paper at the start and at the end,
a pic might be added to fool it at the appropriate times.

If you do want to try this stick with epson, they use bipolar steppers
in the cheap printers and the print heads are hackable.

B: Go full custom, use an epson print head as they are stand alone and
have tubes going to them, you would need to learn the voltage and
pulse requirements to drive the head though. Then there is the
software.... dunno.

The first option seems best, the page per minute of a printer is
fairly high, you can probably kid it there is no paper between "pages"
giving you time to sort the next layer out. I would guess that a CAD
guru could probably write the app to produce the layers from cad and
send them to the printer quite easily. You then need someone to get
very friendly with a printer to learn its ways. Add a bit of pic
programming and a lot of playing with corn starch and you might have a
working machine. Or not :)

Cheers,

Graham