Re: 3D printing, powder spreading

On the unit I got from teh dumpster, the part was 'printed' with some
hot polimer, then trimmed with a rotating cuter. much like an old
style lawnmower.

So, each pass of the printing was followed by a pass of the cutter.

the part was then lowered by some increment and the next layer was
laid down.

I never saw it work, but the roller seems to be sharp and rotate.

Dave




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Graham Stabler" <grezmos@...>
wrote:

>
>
> In a printer like the ones made by zcorp:
>
> http://www.zcorp.com/
>
> They have two vats with motorized pistons, one in which the powder to
> be used it stored and one in which the model is built, as the model is
> built its platform sinks and the powder hopper rises. The powder is
> then transfered from one side of the platform to the next.
>
> A video is worth 10million words:
>
> http://www.youtube.com/watch?v=lDNLk7XvhRc
>
> Pause it, let it download and then skip to 5:21
>
> I don't understand a word they are saying but its the best video I can
> find.
>
> Someone in the past said a roller moved the powder, that can't be the
> case it just wouldn't work, it would compress but not move, however
> there is a roller but I THINK it is spinning quickly in the opposite
> direction, its a bit hard to say so I'm guessing a squeegy pushes the
> powder and the roller makes sure it is level by flicking off the very
> top layer. Notice that the build area lowers a little before the
> printing so the roller does not catch it and also that the roller
> reverse direction and spins off the excess at the end of travel.
>
> Can anyone confirm this or does anyone have any ideas?
>
> Cheers,
>
> Graham
>