Cause and Effect: How Lens Technologies Can Influence Lab Efficiency

By Julie Bos

Continually adapting to new lens technologies is no cake walk. For every new lens, coating or technology, there are countless ripple effects for laboratories. Some are positive—like increased revenue, less waste and greater customer satisfaction. Other changes, however, may shake things up a bit, requiring the purchase of new equipment, revamping some workflows or even expanding your workforce.

Certainly the pros outweigh the cons (otherwise no lab would jump on board with new products), but it’s always nice to be prepared and keep the surprises to a minimum. If your lab is considering adopting a newer lens technology, knowing exactly what you’re up against (and how other labs have addressed the same issue) may help you avoid some headaches and improve your chances for a successful transition.

We reached out to several leading labs to hear about their product-adoption journeys.

Freeform Ain’t Free

Believe it or not, there are still some labs that have not yet made the transition to digital freeform processing. If you’re one of those labs, the following perspectives may be helpful.

For Cherry Optical, freeform is now “the rule” for progressive lens designs. Single-vision and enhanced bifocals are slowly gaining momentum, but for PALs, this lab is already at 99 percent freeform. According to Adam Cherry, President, the efficiency gains have been “outstanding.” He credits his success to great collaboration with freeform vendors and excellent lab management software (he uses the DVI).

Full Back-Side (FBS) freeform technology has streamlined Cherry Optical’s lens inventory while also expanding material and color availability. While the cost of equipment for freeform may be much greater than it is with conventional surfacing, the cost of scrap and warranty replacements has been reduced dramatically.

“Converting from conventional surfacing to digital surfacing is a big undertaking for any optical laboratory,” said Cherry. “The skill sets are similar, but digital surfacing requires a lot more attention to process control since the polishing step will not correct errors or allow for ‘professional adjustments.’”

To do digital surfacing correctly, Cherry offers these tips:

  • Don’t try to “do it cheap.” Give special attention to room environment (sustained heat/humidity), coolant temperature (very important), polish temperature and Baume.
  • Trying to cut corners or extend the life of tools and pads will only lead to increased scrap and headaches. Follow the equipment manufacturers’ guidelines for tool and pad usage. (In fact, Cherry Optical reduces manufacturers’ recommendations by 10 percent just to prevent possible issues.)
  • Assign the right workers. You’ll need organized people who are very detail-oriented and comfortable with ultra-precise calibration procedures. Forgetting a PM, entering calibration data incorrectly or relying on auto-calibration will cost lots of additional money over time. 

Meanwhile, FEA Industries started working with digital freeform designs about six years ago, and the increased level of efficiency has been huge.       

“The transition has greatly reduced our lab’s level of inventory, which has reduced the likelihood of backorders and increased turnaround time tremendously,” said Bill Heffner, Marketing Director. “It also means that we can be more competitive on pricing, since we don’t have to carry large dollar amounts of inventory, and have much less inventory on hand.”

At the time of transition, FEA already owned the necessary equipment because it needed additional capacity, even for traditional surfacing. However, it still needed to update some generators and polishers, and add some new equipment, like a laser engraver.

In addition to updated equipment, the transition to freeform required a few process changes:

  • A switch to more “soft” polishing tools. Instead of using hard tools to pick the correct base and cross curve, labs now simply use one of a very limited selection of “soft tools” that conform to a wide number of curves.
  • Simpler training. Training staff members on freeform wasn’t much different than other surfacing methods. In fact, Heffner claims it was easier. Since the machine was taking over a lot of the calculations and tool-selection decisions, there was actually less for the staff to do.
  • More time needed for quality control. When implementing freeform, the lab essentially becomes the manufacturer of the progressive. That means there’s more to control in terms of the process and quality inspection. This often means more frequent calibration, maintenance and refreshing of consumables (for example, polish, cutting bits) is necessary. Heffner’s tip: Don’t try to stretch consumables, since this will result in an immediate decrease in quality.

Finally, Walman Optical began implementing in-house digital processing in 2007 because it knew freeform was the future of lens manufacturing. Since then, the transition to the still-new technology has yielded a number of benefits for the lab.    

“It has allowed us to reduce our costs on those products, providing us as independents a greater ability to be more competitive with vertically integrated competitors, and allowed us to have a faster turnaround time with our customers,” said Jon Nordman, Director, Optical Service Center.

However, to make the transition, Walman needed to make a few internal changes:

  • Purchase new equipment. Before implementing the digital processing line, the lab had one generator, one polisher and one laser. Today, the lab has 20 generators, 21 polishers and eight lasers. In order to keep up the inventory of digital lenses, the lab needed to ramp up its equipment and lab space to accommodate it all. In order to maximize efficiencies, Walman has centralized its digital and non-glare manufacturing to four facilities, which service the 32 branch locations across the country.
  • Change the workforce. Walman needed to hire new lab staff to cover the new equipment and new processes. 
  • Learn new digital processes. This step can be tedious and time-consuming. Nordman’s advice: It’s best to first start doing toric work with the equipment, to help fine-tune the process and add capabilities, as needed. Once your lab is ready, introduce the digital processing. This makes the transition process much easier.

No Dip, With Dip

Dip coating is another technology that has changed the way labs think about their processes. While this practice has become much more commonplace in recent years, it also presents some new and unique challenges.

FEA has used dip coating for the past four years—and has learned much along the way. “Prior to dip coating, labs would simply use a spin coat on the backside,” said Heffner. “With dip coating, however, labs now need to address the front side of the lens as well as the back. While the back of the lens is raw material, the front side is often already coated. This necessitates a process to either remove or ‘rough up’ the front surface in order for the dip coating to successfully adhere. Unfortunately, different lens materials and coatings often respond differently to various processes, which means labs need to maintain multiple procedures to accommodate them all.”

With a few years of experience, Heffner offers these suggestions to labs considering adopting dip coating:

Don’t try to create a one-size-fits-all process. Every manufacturer has different coatings, so trying to devise a universal process is an easy way to cause defects or otherwise destroy lenses. For labs that deal with a large number of products, determining the correct processes for each lens and material type can be quite an ordeal. The payoff, however, is a superior scratch coating, as well as solid improvements to AR coating performance.

Be prepared to make some investments. Creating an effective environment for dip coating is essential. While backside spin coating can be done in a normal lab environment, dip coating is a totally different animal. It needs a clean room that’s temperature- and humidity-controlled. Your lab will also need ovens for the curing/drying process—usually several of them at different temperatures, to accommodate different materials.  

Additional staff (and more training) may be required. There are many steps that go into dip coating. You have to pre-clean and prepare the lenses before they go into the coater, run them through the coater, then make sure the lenses are properly cured afterward. This is much more involved than the “normal” hard coating process.

Don’t expect to save time. For FEA Industries, adding dip coating actually made the lens fabrication process longer, since dip coating takes longer than spin coating. However, the quality of the hard coat that is produced from this process far outweighs the additional process time.

Successful incorporation of a novel lens product can be a boon for your lab as well as for your customers. And while the journey to success will be different for individual labs, being prepared to make changes to your processes will help smooth the path. ■


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Labtalk-November/December 2017