Thanks to - Precision Optical Laboratory A full service optical lab 7148 Midlothian TurnpikeRichmond, VA 23225For Information Call 804-745-0171Fax at 804-745-5817

Surfacing Overview In PicturesAlso Called: Generating, GrindingThe creation of lens power through the grinding of curvesDL = D1 + D2

Surfacing Is ---How a lens is createdLens begins as a chunk of plastic (or glass) that is finished on the front but is just raw plastic (or glass) on the backThe back side is ground away with great precision with specific curves to match the curve on the frontThis creates the necessary power or prescription

The Nominal Lens Formula DL= D1 + D2DL = The power of a lens in dioptersD1 = The front curve or powerD2 = The back curve or powerDL = D1 is +8.00 D2 is -7.00+ 8.00 + -7.00 = +1.00DL = +1.00

DL= D1 + D2If the front base curve is a convex shape with positive or +8.00 powerAnd the desired Rx is +1.00I will need to grind a concave minus -7.00 curve on the back of the lens

Surfacing Is A 3 Step ProcessGrinding (surfacing, generating)Removes material from back of lensFiningBrings backside of lens to almost clearPolishingBrings backside of lens to perfect smooth clear finish that you can see through

Job Order FormsIt takes thousands of individual calculations to determine what curves will be ground.

Lens blanks come from the factory finished on the front but just raw plastic on the back

Lens BlanksA lab will stock thousands of them!

Lens Blank StockS/V, Lined, Progressive, Transition, Polarized, Occupational, CR-39, Poly, Glass, Hi-Index

Preparing Lens BlankFor all sphero-cylinder lenses axis position must be marked before blocking the lens

Protecting Lens BlankPlastic film placed over the front of the lens protects it from heat and scratching

Lens Is BlockedAlloy or wax is used to hold the lens blank to the surfacing blockThe block holds the lens in place through entire surfacing process

Lens blank is held to bock with alloyBlock assures proper alignment in grinderAlloy creates bond with the lens & tapeAlloy is melted and reused

Lens blank attached to blockNote the various openings that hold block in the correct position

Job Ready for SurfacingJob ticket for grinding parameters, lenses attached to blocks

Surfacing Layout ScreenProvides all the information that the generator needs to complete the jobJob numberBase curveCross curveCenter thicknessCrib diameterPin BevelLayout AxisPrismFront curveBack curveEdge thicknessDiameterMaterialBlockToolArent you glad we have computers!

Generator Cutting Wheel and Chuck ChamberThe orange nozzle sprays water on the lens and tool for coolingThe tool seen on the right has diamond blades that will cut away the back of the lensThe lens is seen on the left

Lens Off GeneratorNote Faint Red Axis LineLens back side is now an opaque smooth white with defined curves

FiningLens is chucked in machineLens is sandwiched between block and a mild abrasive padWater or lubricant is sprayed on pad while pad oscillates over a tool that matches the backside curves with near perfect precision

Job TraySurfaced LensesLap Tools With Fining Pads

A lab must stock thousands of tools to match the nearly infinite number of prescription curves

Tools may be for spheres or sphero-cylinder prescriptions

Machine holds lens in place using the block and pushes it against the tool which is covered with an abrasive pad.

FiningPerformed on a cylinder machine

Fining process

Lens Ready For PolishingNote how thin the lens is now

Polishing Uses same technique as fining but uses a soft pad and mild abrasive slurry instead.

Lens After Surface, Fine and PolishReady for de-blocking and finishing

Also See PowerPoint Presentation On FinishingFinishing is the cutting of the surfaced lens to fit a frame

Labs AlsoStock single vision un-cut lensesTint lensesDrill lensesAssemble complete pairsAdd decorative touches to lensesSome stock framesSome apply anti-reflective coatings in houseLabs can be as small as a few hundred square feet or as large as a factory

TAKE A TOUR!Contact your nearest optical lab and ask for a detailed tour.Ask Questions!Spend the day!LEARN!