A special surface saver tape is applied on to the front surface of the lens to prevent it from any damage.
The semi finished lens is then blocked on CNC blockers using low melting alloys. The CNC blocker reads the Rx data from the Rx server and automatically induces required prism, de-centeration and axis in the semi finished lens.
Here the semi finished lens is cut to its final curve and thickness by a diamond tool. This operation is done on a machine called generator. This is a versatile machine, which can cut the desired curve on the semi finished lens surface, fast and accurate. The generator also reads the data from the Rx server.
Smoothing is removing the grinding marks from the surface of the semi finished lens without changing its curvature. Here the lens is brought to the exact curve required and surface is smoothened not to have any mark or scratches.
This operation is identical to the previous one. The lens is polished on a felt pad or a special plastic pad by a very fine polishing chemical mixed with water.
Quality Control Check
To ensure that lenses do not have any surface defect, have the right thickness and accurate power; stringent quality check is done using high-end lensometers by our qualified personnel.
In this process, the lens is super cleaned by ultrasonic, then dipped in lacquer maintained in super clean environment and at sub zero temperature. The lens is then withdrawn from this lacquer by robot PC controls and goes through 2 types of polymerization. 1st stage – 750C for 5 minutes. 2nd stage – 1150C for 2 hours.
AR Coating (Anti-Reflection Coating)
The application of an AR coating can virtually eliminate unpleasant mirroring effects and reflections in the lenses that can impede vision. The process of AR coating varies from mineral or organic lenses and also varies as per refractive index of the lenses.