I’m having a lens injection molded. (Almost 1/2" thick in the middle).
We’re finding that with polycarbonate, the plastic tends to “sink”, causing lens distortion. The engineers suggest using GPPS which I haven’t seen yet, but I’m told is not glass-clear as polycarbonate is. I need both clarity and smoothness. What should I do?!?!? Someone please help me. Is there a material that has both properties I need?
Have you spoken with your tooling supplier to investigate other possible remedies to the sink? It may be a modification of tooling parameters or the tool design itself that needs to be looked at. PC should be a good material for lenses.
With molding you will always have some shrinkage though generally less with higher grade polymers such as PPSU/Radel.
I advise to CNC them instead, acrylic will be a good alternative.
If you’re going for mid level (on the higher end of mid) or high levels of production though CNC will more than likely be cost prohibitive. I would start discussions immediately with your plastic supplier and molder simultaneously, I would be very surprised if they haven’t ran into a similar issue in the past that they can lean on for understanding.