Diy it?

[amoose136]

The resin needs to be exposed to UV light "X" amount of time to set. You can do that in 2 ways: quick repeated passes (so you would actually see it as lines, not a dot) or slowly so it only needs a single pass... Total amount of exposure time required remains the same in both options!
The latter allows for more accuracy...

Which one would you prefer?

But with a more powerful diode it should be possible to speed up the laser to the limit of the accuracy of the galvo system. There might be hard chemical/physical limits to the curing speed though so it might be that adding more light won't make it cure any faster beyond a certain point.

[CescoAiel]

True, but it also increases the risk of UV light bleeding through in to deeper layers and curing deeper/more than intended...
So it's a balancing act really and their original goal of a less than $100 printer also set some limits...

[amoose136]

I was thinking about that and ideally I would think you would want a system to maintain the resin layer depth at the desired thickness of each layer and then have the laser intentionally cure it all the way through.

[CescoAiel]

Not really, since the amount of resin used will not be constant, so you'd need a way of measuring that, and that is ignoring viscosity and flow rate challenges...
This system works because the cured layer will absorb the UV so lower layers can't be accidentally cured along. But when the UV light gets more intense that may not be the case anymore!

[amoose136]

You wouldn't need to measure the amount of resin used just the thickness of the layer above the saline and if it's not enough, add more. If the interface wasn't moving this would actually be quite easy to do using a variation of the old auto refilling dog bowl trick and some clever pneumatic valves.

[CescoAiel]

Viscosity and flowrate remain a problem in your scenario, the idea behind the thick layer of resin is to provide a bit of a buffer so that the resin can fill the gaps quick enough! With a layer of less than 1mm the surface tension would be a problem and might even lead to pearls of resin floating on top of the water due to hydrophobic behavior!...

[thej]

@Rylan
The structural parts were laser cut from "ABS", correct?
Did you experiment with Acrylic? Did it work?

Apparently, laser cutting ABS produces Hydrogen Cyanide...sooooo, my local maker space will not allow it to be used even though it is well vented. Can't say I blame them!

Acrylic is a safe plastic to laser cut.
I got to test out the cutter tonight and I cut a few parts. Just need to review to assembly instructions to test them out. :-)

[harpo99999]

@thej, it should work assuming you have a sheet at approx the right thickness (I think I had measured it at approx 3mm thick), and the gasses released are part of the issue with the FFF printers and abs also

[Reonarudo]

The resin needs to be exposed to UV light "X" amount of time to set. You can do that in 2 ways: quick repeated passes (so you would actually see it as lines, not a dot) or slowly so it only needs a single pass... Total amount of exposure time required remains the same in both options!
The latter allows for more accuracy...

Which one would you prefer?

Can you provide some reference to this or elaborate? It isn't a very scientific explanation.
Will a more powerful laser need less time?
Is it irrelevant the laser power because the curing time only depends on the resin?
Why does a single pass offer more accuracy? Its counter intuitive for me, could you elaborate?

[CescoAiel]

It is all about inertia and inertial dampening...

Slower means the mirrors need to move less, and not as fast. For a magnetically activated *and* dampened system that certainly makes a difference.

Compare it to a car: can you make a tight turn better at 5MPH or 50MPH?