Maximum Overhang?

[Slatye]

Umm you sure about that.
I understood the even on the original model the dripper was controlled.
Either that or the laser has to cover the entire surface of the print vessel for every single layer. Which would set a specific print time per layer that would allow any part of the surface to be printed.
Otherwise it would be impossible to print different things on each layer - the very definition of 3d printing.
Either way you can print the entire surface per layer.
And the resin must be less dense than the water otherwise the whole thing just would not work.

The dripper is only "controlled" by a manual valve - the printer itself can't change the drip rate. As Synchron has said, if you replace the dripper with a pump then you can print a perfect 90 degree overhang, or maybe even more (in that you can run the pump backwards and effectively re-print earlier layers, as long as the parts you need to access aren't shadowed by parts already printed).

To be able to create absolutely any part (with overhangs to 90 degrees, but no more than that) with the whole surface being touched at every layer, you would indeed need to set the drip rate to a very low level so that the laser would have time to cover the whole print area. This is not practical. Instead, you make an estimate at how much of the area the laser will actually need to cover (probably something like 1%, since you'd normally just print a shell rather than a solid object) and set the dripper to allow that much time.

Because the layer height is so small, the laser can probably cure a couple of layers at a time - so if it takes three layers to get to every part of the job then it'll probably still be fine (although possibly not as smooth).


The challenge is when you do want a very large amount of stuff done on one layer, like a big flat surface. If you want to print fast, you need active water level control so it can slow down for this part and then speed up for others. With the dripper, you'll just have to turn down the speed until the result is acceptable.

[Morten]

So overall print speed can be optimized if we augment our Peachy with a micropump of some kind, and for some prints this can be a dramatic increase? Has anyone started trying to use a motorised pump yet?