To increase transmissivity of FDM parts:
Make part with ABSi (air gap: 0.004 inchs/0.1 mm).
Infiltrate part in transparent epoxy resin in proper mixing rate of main resin and hardener.
Remove the extra epoxy resin on the surface with tools like a putty remover.
Dry the part in the oven (30-35C) for 15-20 minutes and continuously dry it at
normal temperature until it dries perfectly.
Time required for this process depends on part shape. The sample part at left takes 3-4 hours to dry completely.
After this process transmissivity of FDM part increased from 5% to 39% and part strength is about the same as the original part. As a result we can get a durable ABS part with more than a 39% transmissivity increase.