Today we're making lenses with epoxy, using a replication molding technique. It... mostly works 😇 CONSIDER SUBSCRIBING 🥰 ☕Buy me a coffee? https://www.buymeacoffee.com/Breakingtaps 🔬Or Patreon if that's your jam: https://www.patreon.com/breakingtaps 📢Twitter: https://twitter.com/BreakingTaps 💻Discord: https://discord.gg/R45uCXcEv4 ==== Details ==== We can replicate lenses using silicone molds and optical epoxy resin. But there are a lot of caveats to this technique, and little hiccups that will ruin the optical finish. To achieve an optical finish, you need surface roughness and figure deviation in the nanometer range. This means curing temperature and shrinkage become major sources of error. Residual stress in the molded parts can be assessed with polarized light and a polarizer in front of the camera. ==== Prior Videos ==== Injection molded lenses: https://www.youtube.com/watch?v=JNXgHbBIRYQ Microlenses: https://www.youtube.com/watch?v=1tf--Fy5YJw ==== Materials ==== Mold material: Smooth-On Mold Max XLS ii Optical resin: Smooth-On Epoxacast 690 clear ==== Analysis Equipment ==== nGauge AFM from ICSPI (https://www.icspicorp.com/) Phenom XL SEM from Thermo Gwyddion for AFM post-processing Blender for 3D AFM rendering ==== Timeline ==== 0:00 Intro 1:09 Replication Molding 3:04 Alternative mandrel material 3:37 Molding and casting technique 4:30 Fabricated lens examples 7:26 Molding priorities 9:38 Molding materials and considerations 10:49 Mold release difficulties 14:30 Shrinkage difficulties 16:04 Effect of Temperature 17:20 Internal stress and polarized light 18:51 Mechanical difficulties 19:40 Alternatives to silicone? 20:40 Direct molding off mandrel? 21:45 Refinement for future work 23:45 Concluding remarks