Build Your Own SLA/SLS

Hi all, I'm having trouble curing SubG+

As a test, I'm putting a drop of resin on my build platform and waiting for it to cure with the projector at full blast white, on the bright setting (308W). I've left it for over a minute and it's still soft. If I hold the drops a few inches away from the projector, they will cure in a few seconds, but the projector can't focus that close.

From the build plate to the projector is about 10" with a 45* front surface mirror. Top down build.


The projector is an Optoma HD2200.

Am I doing something wrong or is the projector just not putting out enough UV?

Thanks,
Vaughan

Hi,

from what i hear, Projectors must have 2200 Lumen or more to be effective..

your projector is 1900 ANSI lumens.


Kind regards,
hp

Bummer...I guess I will try pico with UV led then...

That's not actually correct, I have a test bed with a Optoma HD65 which is 1600 lumens with a end of life lamp and it will cure resin fine. It did however need a mod to focus closer and the color wheel removed or it would not cure resin properly.
So OP if you haven't removed the color wheel I would do so, you need to remove it from the light path and still have it connected and working. I was able to place mine to the side and fasten it down out of the way.
Also what is your focal distance for the resolution you are trying to cure? I found I had to put a spacer between the inner and outer lens to shorten the distance, it was over 300mm focal now around 250mm which made a very big impact in exposure times.

Ahh, thanks for the info guys. Maybe I'll try to find a broken projector online (or pico) to salvage, dont want to wreck this one. Also I have an old LCD screen lying around I'll test if that will let UV light through.

ah well, thanks for saving me the time. I'm still interested in Pico though...do you think its better to just usea 20W UV in or 3 5w leds where the old ones were?

Has anyone managed a mod of a mercury lamp projector to use UV LEDs? Even giving the LEDs their own power supply, I guess you'd have to trick the projector into thinking the lamp was still connected, but there should be a way.

Regarding the question about single or multiple UV LEDs, I imagine the best is to remove the dichroic mirrors and use a single LED, but I'm not expert.