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Arno’s hand edger features a sponge/ water system that constantly and gradually supplies water to edge any type of lens.
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Many optical dispensers and doctors have little knowledge of what it takes to craft a pair of eyeglasses once the lenses have been surfaced. This operation, known as “finishing,” helps create quality eyewear. Here’s a tour around the finishing department.
TRAY UP
The first thing that’s done is to “tray up” the job (order). A shallow plastic box measuring about 7 in. W x 12 in. H x 2 in. D is typically used; these are available from OptiSource International or Amcon. The front of the tray usually has a slot that holds a tag with the customer’s name, job order, or barcode on it for identification purposes. This tray holds the lenses, the frame, and the job order ticket with all the parameters needed for crafting the eyeglasses.
TRACING
Next is tracing. The frame is placed in a box-like tracing device that has a stylus to trace the exact shape of the frame’s eyewires. Modern tracing machines are extremely accurate so they can trace for shape and the amount of curvature in the eyewires (such
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| USOphthalmic’s Huvitz Auto Blocker CAB 4000 has automated lens centering and blocking available at the push of button. |
as a wrap sunwear). Tracers are available from AIT Industries, Briot USA, Gerber Coburn, National Optronics, Santinelli International, Inc., and Topcon-Lens Edging Division.
LAYOUT AND BLOCKING
At layout, the lenses are placed in a manual or automated lensometer to determine the lens power, axis and center, and any multifocal dimensions needed, like fitting height. With this information, a technician orients the lens properly, either mounting the lens on a block manually or automatically with a blocking unit.
A block is a metal or plastic circular holder attached to the front of the lens so it can be mounted in an edger. Types of double-sided tape securely hold the block to the lens.
After the lenses are marked in layout, they go directly to a blocking machine that automatically aligns and affixes the block in one operation using all the information obtained. These machines can be quite simple with a basic grid and screen (like AIT’s Speede® Blocker and Nu-Tec’s Blockrite) or very advanced (such as the blockers from Gerber Coburn and Santinelli) that display computer-generated images of the shape and lens size, and also have a motorized arm to place the block on the lens.
USOphthalmic’s Huvitz Auto Blocker CAB 4000 has fully automated lens centering and blocking available at the push of button. Users complete all lens layout work, adjust parameters (such as PD & OH values), and select edging using the icon-based touch screen.
EDGING
At this point, the lens is ready for the edger. Edging means shaping lens to the desired size and configuration of the eyewire while placing a bevel or flat edge on it.
Machines range from a basic model that places a simple bevel on a lens to those that
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| Gerber Coburn’s Sigma II can polish the edges of plastic lens materials. |
edge, drill holes, groove, notch, polish lens edges, and provide a number of special bevel types. Most of today’s models all have special cycles for lens materials like polycarbonate, Trivex®, and high-index. These adjust the grinding speeds and coolant flow to improve the grinding outcome.
Many edgers are “wet,” which means they require a liquid coolant to flow as they grind lenses. Edgers such as those from AIT, Briot, Gerber Coburn, and Santi-nelli are some examples. These machines can edge glass lenses and polish the edges of plastic lens materials. National Optronics’ pro-duces a “dry cut” edger (named 7E) that cuts specialty bevels traditional wheeled edgers cannot.
In addition, Arno Optical Corp.’s DIA E-950 edging system has a touch-screen interface that features shape modification technology.
HAND STONE
A manual hand edger (sometimes called a hand stone) enables you to make slight alterations on the lens such as an increased safety bevel or perhaps to alter a lens size and shape to mount it in a frame being used to replace a customer’s broken one.
Arno’s hand edger works with a sponge/water system that allows it to constantly and gradually supply water to edge any type of lens. Other companies that carry hand stones include AIT, Nu-Tec, Lab-Tech, Inc., and USOphthalmic.
DRILL OR GROOVE
If your edger doesn’t have a drilling or grooving function, separate machines are required to achieve these needs. Drilling mach-ines can range from a handheld Dremel rotary tool to an automatic, computer-controlled device. Lens edge grooving machines can be manual or automatic, but there’s no need for anything more complicated than a motor and a small sharp wheel to get the job done.
ALL-IN-ONE An all-in-one machine incorporates tracing, layout, blocking, and edging for an easy and effective method of fabricating eyewear. Most edger manufacturers like Santinelli Inter-national, Inc., Briot USA, and Gerber Coburn make all-in-one machines.
USOphthalmic makes several units including the CPE3000 Excelon EZ 3D Edger and CPE 4000 3D Edger. All the processes from lens layout to selection of edging options in Excelon EZ 3D Edger can be completed through a one-page display without moving to other pages. And all the finishing processes in the 4000 3D Edger are operated with advanced 3-Dimensional Digital Technology optimizing the productivity and efficiency. |
TINTING
All tints are applied using a heated dye, usually with a machine that holds anywhere from six to 12 1-qt. tanks. Dyes can be a condensed liquid or in tablet form. Companies such as Arno, Brain Power, Inc. (BPI), Optisource, Vigor Optical, A Division of Grobet USA, Lab-Tech, Phantom Research Laboratories, Inc., and Western Optical Supply offer a variety of these machines and necessary dyes, UV blockers, neutralizers, and transfer fluids.
Simply place the lens in a holder then put it in the dye until you get the desired color. If a gradient tint is needed, you can do it by hand, but I suggest an automatic gradient de-vice. This unit dips the lens in and out of the dye for a given period of time to accomplish the amount of gradient and density of color.
It’s now time to mount the lenses in the frame. With a metal frame, all you need is a screwdriver. For a plastic frame, either a frame warm-er with salt or glass beads in it or a hot-air blower will do the job.
After the lenses are mounted, a final quality control check is done for Rx, lens materials and lens style, appearance, proper frame alignment, and any cosmetic applications such as tint.
If you have never had the opportunity to watch a finishing pro-cess, ask your local lab to give you a guided tour of their facility.
Larry Guess is a consultant to the optical industry and designer of new optical tools.
WHERE TO FIND IT
AIT Industries
800-729-1959 • aitindustries.com
Amcon
800-255-6161 • amconlabs.com
Arno Optical Corp.
800-822-2766 • arnooptical.com
Brain Power, Inc. (BPI)
800-327-2250 • callbpi.com
Briot USA
800-292-7468 • briot-usa.com
Gerber Coburn
800-843-1479 • gerbercoburn.com
Lab-Tech, Inc.
800-822-4343 • lab-tech.net
National Optronics
800-247-9796 • nationaloptronics.com
Nu-Tec
972-231-4921 • nu-tecinc.com
OptiSource International
800-optisource • 1-800-optisource.com
Phantom Research Laboratories, Inc.
800-225-5559 • phantomresearch.com
Santinelli International, Inc.
800-644-3343 • santinelli.com
Topcon-Lens Edging Division
888-551-2020 • topconmedical.com
USOphthalmic
888-334-4640 • usophthalmic.com
Vigor Optical,
A Division of Grobet USA
800-847-4188 • vigoroptical.com
Western Optical Supply
800-423-3294 • westernoptical.com
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