Light Pipe


#1

I was looking through the forums for information and any history on printing light pipes. Most articles are pretty old and closed. I am using a Form 3 with clear resin doing some experiments making light pipes.Any new updates or resign tricks? One comment stated that the Formlabs process really can’t make light pipes because of the way the laser cures resin . Wondering if a DLP printer would be better because it will cure a whole layer at a time.


#2

I’ve done this before - see image below. It’s better on the Form 3 than the Form 2 because the lower peel forces result in more clear parts.

You need to be careful of your print orientation when making these. The efficacy is probably worse than molded acrylic lenses and the internal reflection is probably worse, but from what I’ve done it works pretty well.

image


#3

How did you cure these without getting the yellowing effect? I use the wash and cure. Did you cure these in a glass of water?


#4

Don’t use the cure machine.
I find yellowing happens when either cured or left in a bright place for a while.,Given you don’t need the extra mechanical strength for light pipes. just wash them and let them dry off, then use them.


#5

Yup exactly what @nwalker said. These don’t need better mechanical properties, so just don’t cure them (or cure them for a shorter time if they’re tacky).

Curing underwater doesn’t prevent parts from yellowing, it prevents parts from staying tacky since it displaces the oxygen near the surface which prevents polymerization.

Note that even if you don’t cure these, they will yellow over time as they age - the speed depends on the environment.