Re: lexmark 3d printer is back (binder & build matl)

This is what I came up with, maltodextrin 25% and 75% regular
plaster. It holds the plaster particles realy well, I've got the
first part out of the machine with that mix printing on high setting
(1200 dpi) and a 0.1mm slice.
It looks very nice.
Just don't add too much dextrin, or the parts starts to curl while
printing.
Dextrin works like glue when it gets wet, I do print and then put
the part on the owen (60 degrees centigrade) for about 30 min then
seal it with cianoacrylate(super bond).
If you don't seal it , it keeps absorving humidity and never gets
hard enough to handle it, it's rainning a lot down here.
The plaster powder sample I've got from zcorp had some kind of
glue mixed with it, probably PVA, so I tough about adding the
dextrin to the plaster and guess what.., it work.
I've to do a little work on the sliding shafts before atempting to
get another part printed out.
Don't know if the parts will come up dimension stable but it was
nice to see it printing ( about 233 layers).
The finish line is not there anymore!!

Fogassa.










--- In CAD_CAM_EDM_DRO@yahoogroups.com, H & J Johnson
<hjjohnson@...> wrote:

>
> Have you guys tried looking through USG.com's site? They have

several

> high performance plasters. One in particular which might work for

you

> is called Rayite100. It has a flash time of 20-30 minutes and comes
> out like plastic [it's a plasticized plaster.. if thats the proper

term]

> just add water. It's origin is as a castable and machinable

plaster.

> It is supposed to machine dust free [just soap like chips]. It's

also

> great for those who want to do test machined parts and patterns
> as well. It's not terribly cheap however, a 22kg bag is ~$125usd..
>
> If that doesn't fit the bill, there may be other types on there

which

> would... they have hundreds of different types of plaster for

different

> applications..
>
> FWIW
> Jarrett Johnson
>
> > Guys - we were going to try dental alginate in our machine, but

never

> > got around to it - in "cup" tests, however, it seemed to perform

just

> > as well (time to solid, absorption, heat, etc) as our original
> > high-performance build material. We also tried a bit of molder's
> > plaster (it does feel finer than wall-patch) with equaled

success, so

> > spread-ability is the real determining factor here (stabilizers

and

> > de-cakers really don't apply to our typical storage times!)
> >
> > I don't know which post it was, but I think I recall one of you
> > mentioning that perhaps "adding a glue to the build

material"....ZC

> > announced on their price list just recently a new premium

performance

> > build material with binder added for greater green
> > strength...small world.
> >
> > Ted.
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "afogassa" <afogassa@>
> > wrote:>
> > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Graham Stabler"
> > > <grezmos@> wrote:
> > > >
> > > >
> > > > > Santa stop by to help me out :)
> > > > > The roler came from a old lexmark laser printer toner
> > cartridge.> > > it's aluminum an about 30mm diameter.
> > > > >
> > > >
> > > > I used to have a nice roller like that but thought I would
> > never
> > > need
> > > > it, should be easy to find one though.
> > > >
> > > > What about the rotation speed, have you synced it to the
> > movement
> > > of
> > > > the gantry or did you just experiment? How well does it

work

> > and
> > > do
> > > > you think the plaster used is of great importance, you used

zcorp

> > > > stuff right?
> > > >
> > > > Cheers,
> > > >
> > > > Graham
> > > >
> > >
> > > I'm using just plain plaster, it does not spreads nice.
> > > Zcorp plaster is granulated, almost like refined sugar, it
> > should
> > > spread very nice, I don't have enough zcorp powder to fill the
> > > feeding bin with it, so can't tell for shure.
> > > i've tried refined sugar and it spreads very nice.
> > > The rotation speed was just to get the powder spread,not

shure

> > at
> > > what speed it's rotating, I guess it's about 200rpm.
> > > The type of plaster is very important, as it should spread
> > without
> > > lumps.
> > > There is a granulated dental plaster that I've to check it

out.

> > > I think that the main thing is to get the right binder or

glue

> > to
> > > hold the plaster particles togheter and does not clog the
> > printer
> > > head, that's a tough one.
> > >
> >
> >
> >
> >
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