Re: [CAD_CAM_EDM_DRO] Re: LCDs and UV

On Wednesday 03 January 2007 18:57, Graham Stabler wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@...> wrote:
> > Also, if you can keep it cool, the DLP can handle a
> > LOT of
> > light -- like a 1000 W Xenon arc lamp focussed on a thumbnail. The
> > trick is the
> > DLP shines the mirror spots on the target, or on a black beam dump.
> >
> >The LCD absorbs the light not wanted. Turn the "screen" black, and
>
> it >has to absorb the entire 1000 W in the polarizers! Poof!
>
> The question becomes how much power does the hardening of the resin
> require? Assuming the very near UV resin was used as per the paper
> (460nm). A wide field system has the advantage over a scanning on of
> speed so if it requires greater exposure times because of lower power
> it might not be so bad.
>
> DLPs are certaily nice but I had a feeling they were a tad expensive
> to play with. Anyone any ideas?
>
> Also note that the system linked to is inverted, that means no
> complicated fluid leveling systems are required.
>
> Graham

I think it's probably doable, if not already done, but I favor a FDM (hot-glue
gun or syringe-squeezer) type fabber, just because you have a much wider
range of materials you can put down. In the case of FDM, you can put a
fairly wide range of cheap thermoplastics into it.

Using light to polymerize monomer into hard plastic means you're restricted to
using to buying photo-sensitive goop that's definitely going to be more
expensive than your FDM feedstock. You'll have to buy your goop from a
smaller number of suppliers who may not be eager to deal with you. For FDM,
you can just go to the hardware store and buy a tube of silicone caulking or
wood filler, or melt down some milk jugs. (Or more likely, buy bags of
plastic pellets from a supplier/recycle old print-outs.)

The mechanical side of FDM is also easier, unless you're more comfortable
around an optical table than a machining workshop.

Of course, I'm biased.

Regards,
Sebastien Bailard
RepRap.org - self-replicating 3D printer project.