Re: 3D printer fun with powder

Well I tried with a bigger roller on its own and that didn't help.

Then I baked the powder and pushed it through a finer sieve using a
rubber spatula.

That has definitely improved things, of course I should have tried
just sieving and then baking and sieving but heck, sue me. Dryness is
definately a good thing anyway.

I added a strip of acetate as a squeegee for the roller to prevent
lots of powder getting thrown back, this also helps and is better than
the rubber one I was using yesterday.

Then I played around with speeds and feeds, its filling the gaps in
the build area better but only if I really move the gantry fast,
otherwise I get the sausages.

Then I remembered an experiment I tried yesterday, basically I tried
pushing the gantry by hand while rotating the roller by hand very
slowly, basically fast enough such that the linear speed of the roller
surface was just faster than the linear speed of the gantry.
Yesterday I saw the lovely clean surface left behind the roller but
the powder coated the roller and eventually it came over the top and
made a mess, today I have the squeegee reinstalled and improved.

The corn flour is strange stuff, I don't know anything about powder
science (if there is such a thing) but I'm getting a feel for it. If
you try and push the powder with a straight edge it tends to dig in to
the layers beneath and sort of tear the surface but if you push it
with a rotating roller, that will tend to lift the powder preventing
it from digging in, it stands to reason that it only needs to spin
just fast enough to do this. At least I think it might, I need to
experiment further, my motor does not go slow enough. Ideally I would
sync the gantry and roller, I may try that if it seems like a winner.

I'm covered in powder :) A drugs bust is probably imminent if the
neighbours spot me.

Graham