Expert Advice, March/April 2013

By Christie Walker

When UV Coating Lenses, Remember: Water is a Solvent

Not everyone realizes that not all water is created equal, and that the type you use in your coating machine can affect your coating results. For most spin-coating machines consider using distilled or R.O. water over D.I. water. The reason some manufacturers recommend D.I water is because it sheets off the lens without leaving streaks or residue. This process is necessary when dip coating, but with coaters using spin and air dry assist, the properties of D.I. water are no longer needed. The down side to D.I. water is that it deteriorates the stainless steel parts of a machine such as wash nozzle tips, pumps, and dump valves at a much more aggressive rate because of its aggressive nature compared to other types of water. The deterioration of these parts is a common cause of pits. Anyone using D.I. water in these coaters will already know about replacing these parts frequently, but they may not know why. Contact the Coburn Technologies coating group for more helpful tips and techniques to improve your coating process and save money. Curt Brey, Vice President of Marketing and Business Development

Coburn Technologies

 

Don’t Mess with the Process

If you own a high-performance vehicle that requires certain fuel and tire requirements, you probably follow those recommendations to ensure maximum results. The same goes for Digital Surfacing, AR Coating and complex edging. Nowadays, there are lots of third parties introducing cheaper and lower cost process consumables but often without a complete understanding of downstream quality results. Today’s sophisticated equipment and processes are far more susceptible to deviations caused by non-OEM supplied process consumables. In order to deliver maximum quality and throughput, manufacturers put a lot of engineering time and resources into things like polish pads, polish and cutting blades. By following manufacturer’s recommendations, you put yourself in the best possible position to achieve the results that you’re looking for—THE RIGHT TOOL FOR THE JOB! Implementing non-OEM supplied process consumables and then asking the manufacturer to support your sophisticated process makes the troubleshooting process longer and more difficult, as the machines are no longer tuned according to the factory specifications. Introducing non-OEM supplied process consumables can sound like a good, money saving idea until your realize how many lenses end up on the breakage shelf. If you truly want to save money on the process it is always a good bet that using what the manufacturer recommends will work best over the long haul. Kevin Cross, Director of Sales, North America Schneider Optical Machines

 

Inspecting What you Expect

Because the majority of laboratories are producing digital progressive designs, the demand for measuring and validating complex surfaces has increased. Whether it’s day-to-day confirmation of process and design integrity or troubleshooting when things go wrong, it is important to be able to objectively evaluate your finished product. Measuring the surface of a conventionally processed lens is pretty simple—with an arc lamp and a sag gauge you can tell pretty much everything you need to know. Not so with a complex lens surface.

In general there are three ways to verify that the digital work produced is up to standard.

1.                   Send the lens design company daily or weekly samples for measurement and evaluation. This method ensures design integrity meeting the vendor’s standard but does not provide real-time feedback.

2.                   Measure the lens yourself using a device that employs through power imaging, which is certainly more convenient but can be challenging to filter out any issues that may occur on the front surface of the lens.

3.                   Evaluate the lens surface using a CMM (Coordinate Measuring Machine) technique, which is the most accurate but has traditionally been both time consuming and expensive (CMM machines typically cost in excess of $200K).

 

Satisloh’s VFT series generators feature an ITM (Integrated Topography Measurement) option for measuring complex surfaces. For less than $10K this revolutionary process, based on CMM technology, allows the operator to perform a very precise measurement of a generated or polished surface in about 60 seconds. The measurement can then be compared to the original design file with any deviation displayed through a graphical user interface. This method is both convenient and extremely accurate. It also provides a high level of IT security for your Lens Design provider because the original design file is not downloaded to a separate system and the resulting data file contains only the difference between the original file and the measured results. Ian Gregg, Director Surfacing Products Satisloh

 

Standardized Care and Operational Health of Your Equipment

Wholesale labs may use a mix of different equipment vendors for their finish tracing, blocking, and edging needs with seamless connectivity. However, too little attention is paid to the long-term goal of standardized care and operational health of each piece of the finishing dynamic. Equipment varies in robustness, short-term routine maintenance needs, as well as longer term preventative maintenance requirements in order to keep costs and downtime in check. This requires a vendor partnership throughout the life of the equipment, well beyond installation, training, and warranty coverage. Such expectations would require a thorough vetting prior to purchase. Simply the long term cost of parts, onsite or remote service, and availability of continual training throughout the lifetime of the equipment would be an invaluable discussion to have with any vendor under consideration. This is the best way to assure continual customer satisfaction as well as consistent operational equipment performance throughout the life cycle. It would behoove the buyer to get an understanding of possible extended service programs available that include annual visits for preventative maintenance, discounts on parts and consumables, and onsite discounted labor rates. Steve Swalgen, National Director, Lab BusinessSantinelli, International

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