Understanding Light Exposure and Resin

Hi, just got my first SLA printer (Form 2). I’m feeling pretty confident about the process, but there’s one part I’m a little stuck on, can’t seem to find a direct answer in the Formlabs guides.

I understand that the resin is light sensitive, so when I open the orange light shield to retrieve my print, what happens to the resin in the tank? Does it become contaminated and should be thrown out after every print, or is it good until I notice cured resin in the tank and throw that out? I see the tank-cover, do I need to throw that on every time I go to open the tank?

Should I be manic when it comes to limiting the light exposure to almost nothing (turning out lights, covering with a blanket, etc), or can I be less concerned, as a few minutes open is not going to hurt it? This stuff is expensive, so I’d understandably like to get as much out of it as possible.

a few minutes is ok with no direct sunlight or a lot of lighting. I would turn down the lights a little .

The Formlabs Resins need quite a lot of light to cure (as opposed to some resins for DLP printers). As long as you don’t have the sun shining on the printer directly, I wouldn’t worry.

You should absolutely not be manic when it comes to light exposure. When I have not used a tank in a few days and the resin that is in it has a tendency to settle, I often put the tank on a clean surface and stirr the resin for 5minutes or more to get it back to a homogeneous state.

Technically, the amount of energy necessary to initiate the photo-polymerisation of the resin is HUGE in comparison to the amount of energy within the right bandwidth (~405nm) that is present in natural light or artificial interior lighting fixtures.

my form 2 is in a warehouse that is relatively well lit AND i consistently shine an LED flashlight through the orange cover so that i can get a better look inside.

ambient light exposure has little effect on uncured resin.

The cover is meant to filter out the light to where it’s not going to get cured when the cover is closed. When opening the cover, it’s probably best practice to turn down the lights, at the very least make sure that the window shades are down since sunlight has a much stronger effect than indoor lighting.
I put a box over the printer while it’s not being used, at the very least it keeps dust off the printer.

That shouldn’t be necessary if all you’re doing is placing and removing a tank or a build plate.

This is a terrific thing to keep in mind while you’re working, but I’ll echo some other folks in this thread. The resin isn’t sensitive enough to require undue rushing or changing of lights. As long as the printer isn’t in /-direct sunlight, 10-20 minutes with the cover open isn’t anything to be concerned about. :slight_smile:

As for when the cover is closed, you can pretty much put a printer anywhere. The cover is designed to block UV light and it does that very well!