Preventing Spoilage
This OLA-sponsored article explains how a little care can go a long way toward avoiding spoilage and saving hundreds of dollars
by Alex Yoho, ABOM
Spoilage is a dreaded lab occurrence. It eats into profit and is probably responsible for many price increases in our industry. The causes are many—but, there are also many ways to fight spoilage.
EDITING FOR CLARITY
When a job comes into the lab, someone has to determine its routing. This person can also look over the order and highlight what needs special attention. A person in this capacity should have a firm grasp of every process in the lab and be familiar with various dispensers' preferences.
There is no rhyme or reason to where on the order form dispensers will write a special instruction. Some accounts will use their own computer-generated forms, which place the information in different areas on the order form. Ensuring the proper information is brought to attention is critical since missing just one small detail can result in hundreds of dollars in spoilage.
Imagine a rimless job with all of the proverbial bells and whistles: ultra high index, premium AR, in an exotic frame with screws that are welded to the frame. As it crosses the final inspector's desk, she notices that a high base curve for lashes was ordered but the editor missed it. Not only will the lenses need to be remade, but the job is delayed, everyone will have to do the same operations all over again, and the frame may need to be replaced because after finishing the screws, they are too short to reuse.
Unfortunately, the editor cannot catch everything. If there is not enough information, it's impossible to second-guess the order. For example, a minus three diopter prescription with a bit of cylinder to boot may be ordered with the unknown frame to follow. The lenses are processed normally on the standard low base curve for the prescription.
When the frame arrives, it is a wrapped frame that must have a high base curve to even consider mounting in this frame. After recomputing the job for the new base curve, it is discovered that the lens isn't thick enough to grind the surface all the way across the lens, and even if we could, the PD is so narrow there is not enough blank size to cut the shape. This job has been in the lab for a week and now the dispenser will have to call the patient and explain that the selected frame won't work.
| Equipment Pointers |
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| Equipment calibration and maintenance is by far one of the most important things a lab can do to prevent spoilage. In a large lab, 50 jobs could get through before an inspection starts to catch the problem. In a small lab, the problem is just as significant, and without backup equipment, could shut the lab down. Simply keeping the equipment clean can make a profound difference. Tracer calibration, curve calibration, and edger calibration should be checked several times a day depending on the equipment used. An edger running small might not be discovered until the mounter gets back from lunch. By then it's too late and the job must be started over. Though many machines are automatically set for curve, thickness, or size, an operator still needs to be vigilant and experienced to catch the various nuances that will prevent spoilage. A temporary worker might be able to run lenses through a machine all day long, but it requires experience to know that changing the bevel placement on an edger will allow that clip to fit on the frame. And only an experienced person will adjust the consistency of the lens polish to prevent poor surfaces if a lab is a little warm on a hot day. |
TRACING THE FRAMES
Frame tracing seems pretty simple—pop the frame into the tracer and it does the rest. But when frames come into the lab, they may or may not be in traceable condition. Sometimes even a new frame will not meet well at the eyewire closure. This can cause the stylus to jump out of the groove or cause a bump on the lens. So the frame groove may have to be smoothed out before a good trace can be accomplished.
Remember: you get what you trace. The tracer operator has to be an artist with good sense of what a frame should look like. Sometimes a frame can be difficult to clamp in the tracer. It takes a delicate touch to hold the frame by hand so as not to squish the frame, causing the shape to be narrower than intended.
PULLING MATERIALS
This is an area where spoilage has been greatly reduced thanks to computerized inventory in larger labs. Computers verify the lenses and frames pulled for the job with the barcode on the work ticket.
In smaller labs, human error creeps in and the wrong parts can be pulled. A +2.00 lens would normally be ground on a +8.00 base curve, but if a +6.00 base curve was pulled by accident, the lens would be around a plano after surfacing.
Pulling a smaller eye size on a frame might pass the dispenser's final inspection, but when they put the finished job on "Big Bill," the error becomes manifest.
HANDLING WITH CARE
It's tempting to move a large stack of job trays from one place to the other, and one would think it would be more efficient. But if there is a large frame lifting up a tray in the middle of a stack, everything may tumble to the floor, resulting in breakage.
There is also potential for mixups as things are returned to the trays. To prevent this type of spoilage, a little common sense and care can save hundreds of dollars.
| Double-Check the Data |
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| Data entry is an area that takes extreme care. One misplaced decimal point could mean the difference between producing a +2.00 or a +20.00 lens. A minus sign entered for a cylinder instead of a plus sign makes a whole different lens. Though order entry software has reduced the possibility of data entry errors by eliminating the need for someone to reenter hand-written orders, there are often instructions that aren't translated by the computer automatically. For this reason, the orders must be double-checked for accuracy and missed instructions. |
PROVIDING PROTECTION
Lenses can be soft in an uncoated state. Protecting them from contaminants before they are coated is crucial, so labs often bag the work trays to protect the lenses.
It's also important to protect the surface that is not being worked during the grinding process with plastic film on the lens' front. Otherwise, even with a block attached to the front surface, exposed edges could get scratched. The film also protects the surfaces from the heat of blocking.
During edging, a smaller tape is put on the lens. Depending on how it is blocked, this may or may not protect the lens from heat, but it helps keep the lenses from slipping on the block during edging. This is important with slippery super AR options.
When assembling the eyewear, protective films are often applied to prevent lens scratching during handling. A lens that is this far along is even more costly if spoiled, so protecting it is a smart move. EB
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