Re: 3D printer fun with powder

Graham,
when making abrasive wheels they use radial spiral blades to even
end spread the powder. In your case may be to use a blade which is
at the angle or curved , similar to a snow plow? May be behind the
blade have a piece of flat to furter smoothen the surface?
Alex

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

>
> An interesting aside on photocopiers and laser printers but lets get
> back to 3D printing.
>
> A fellow aeromodeler was kind enough to make a video of the roller
> spreading the powder, he even marked the roller with a black mark so I
> could see the relative motion of roller and gantry. I've asked about
> the clearing scraper but it seems a no-brainer and I feel sure I can
> actually hear it in the video.
>
> As I suspected the distance traveled by the gantry was basically the
> same as the circumference of the roller multiplied by the number of
> revolutions it performed over the distance, in other words the roller
> does just enough to ensure that the powder it is pushing does not dig
> in and nothing more.
>
> I'll stick a stepper on the roller and assemble the gantry belt drive
> and then set to work doing the firmware, it should not be too much of
> an issue, I can set one pin to operate at some divider of another
> using one of the hardware counters, so the roller will be synced to
> the gantry.
>
> I also had a most amusing and exciting idea, I'm wondering about
> picking up a little Lexmark photo printer we know the Lexmarks tend to
> be dumber so that will make things easier. Nema11 motors are quite
> cheap if you know where to go and it could be seriously tiny and still
> have a useful build volume. But first I must get this one working!
>
> Thanks for all the ideas everyone and the asides, its all very
> interesting and thought provoking.
>
> Graham
>