Name the 3 steps in surfacing.

• A. Grinding, Fining, Polishing
• B. Cutting, Grinding, Polishing
• C. Smoothing, Finishing, Polishing
• D. Grinding, Sanding, Polishing

Answer: (A)

Surfacing a lens is about shaping and smoothing the surface through a progression of abrasive steps to achieve the desired curvature and optical quality. The first step uses coarse abrasives to remove material and establish the approximate curvature and thickness; this is grinding. The next step uses finer abrasives to smooth out the grooves and scratches left by grinding, refining the surface toward its final shape; this is fining. The final step employs very fine abrasives to eliminate micro-scratches and produce a smooth, optically clear finish; this is polishing. Skipping the intermediate fining stage would leave noticeable surface irregularities, and skipping polishing would leave residual roughness that degrades optical clarity. Therefore, the three steps in surfacing are grinding, fining, polishing.