Extremely long prints tend to fail, usually due to pigment in the resin settling after a while and blocking too much of the laser intensity reaching the cured spot.
It should be possible to use known settling times (time vs. absorbance of the bottom layer of resin) to change the laser exposure as the print progresses to compensate. This could either be done by gradually increasing the laser power (if enough headroom) or reducing print speed.
If a user pauses the print, they’d get a prompt inquiring whether they’ve agitated the resin or poured more resin in the vat. If they did, the counter (timer) modulating the exposure would reset to 0.
I believe this would increase the success ratio for very long prints.
Ambient temperature can affect the viscosity of the resin, so if the room is warm then the pigment may settle faster vs on cold day or if the air conditioning is blasting, therefore making it near impossible to keep track of the settling of the pigment.
I think the better solution would be to make clear or semi clear resins that don’t use pigments, but instead use dyes. This will help with the printing of the large prints.
Another solutions would be some kind of a sliding/mixing arm mechanism that to keeps the pigment mixed in.
Dies are typically never opaque, so while a solution, it’s probably not a universal one.
Also, pigments are actually good in that they limit cure depth (precisely because of their absorbance). Limited cure depth = smaller “smallest feature” and less “fuzz” on the bottom-facing side of the object.
That’s why the black resin is particularly good for detail, for example.
I agree that pigments are better at controlling depth. Done many experiments regarding this previously
I’m just saying that for tall objects, using the clear resin, or resins colored with dyes can be a better option.
True. Like i’ve said, it’s a solution, although not a universal one