Many opticians find it extremely confusing the process of production of blanks of lenses. What they don’t know is that there are different processes that must be followed depending on the type of lens manufactured. We have been working with optical stores for a long time, where lenses come in the form of blanks for spectacle lenses. In optical shops, these prefabricated lenses are processed on edgers, measured with lensmeters such as Tomey and others, tinted, inserted into a rim, etc. But for our customers, the processes that the lens goes through before appearing in the optician’s remains unclear. We decided to talk about it in this article.
Step-by-step process to create a semi-finished lens
Preparing for the Production
The first step in the production of the lenses is the grinding of the lenses, which will make the vision correction possible. Lens grinding consists of two stages. The first step is to grind the lens. This will be done with a series of different grits. Grit is a grain of sand with a certain amount of coarseness. Its coarseness will determine how accurate the lens will be ground. The more accurate the lens is, the better the vision correction will be.
Blocking Using a Protective Coating
In the world of lens production, there are several ways to block the lens. This is done to prevent the lens from being scratched while the process of making the lenses is taking place. There are several types of protective coatings in lens production. The most commonly used are water-based coating (methanol, isopropyl alcohol, and toluene) and silicone-based coating. They are often mixed together in order to achieve the best result.
A lens blocking is done to fix the lens so that the next step equipment can work on it. It also helps to protect the lens during polishing and to fill up scratches on the lens surface that often occur during this process. The scratches are difficult to remove and will cause the lens to be out of tolerance.
Next, the lens must be given a certain shape and characteristics. When a semi-finished lens comes from the factory, its front surface already has optical power. It is only necessary to process and give the necessary shape to the back surface in accordance with the individual requirements of the owner. Chamfering machines are used for this, which in about 90 seconds give the semi-finished product the correct shape. In general, three main stages are carried out in 1.5 minutes: the lens is hardened, giving them a shape, after which tens of thousands of processing points are set with natural diamond. This method allows you to give it a suitable shape.
When the lens is being manufactured, each piece of glass is measured and sorted by the edger. The edger generally sorts lenses into four generations: coarse, first, second and third. This process makes it possible to personalize the lens.
Polishing and Engraving
The polishing and engraving are among the most important parts of the lens-making process because they give the lenses the required shape and their proper refractive power and focal length. The process is pretty simple and done in four basic steps.
The first step is to turn the lens blank into a negative shape by using a grinding machine. The second step is to polish the lens by using various types and grades of polishing wheels. The third step is to use a polishing compound to polish the lens further, and the final step is to polish out the lens using a machine with a diamond tip.
De-blocking and Cleaning the Lenses
The de-blocking process is an important step in the cleaning of lenses. During it, the alloy that connected lens with the blocker melts and the de-blocked lens is then plunged into hot water. This process is used to remove the blockages that are present after the grinding process has been completed. Here there is also used different cleaning equipment, i.e. brushes, various cleaning products and well-purified water. This process can be quite challenging to the inexperienced. If the lenses are not processed correctly, they can be severely damaged. This process is used to remove the grinding residue from the lens.
Tinting (If Needed)
At this production stage, tint is applied to lenses if required. The necessary shades of glass lenses are applied with technology that uses application of layers of metal oxide. In the individual production of lenses, this step is carried out only by proficient workers to ensure the perfect color of lens tint.
The coating process is the most sophisticated manufacturing process in terms of technology. Why is the coating needed? It prevents the lens from scratches and extends their service life, ensures a patient’s perfect vision in any weather, or any other conditions, be it when driving or working on the smartphone. For the most part, this is done with the help of professional equipment. The lens will be mounted onto a spinning mandrel, then placed into a coating machine. The coating machine will use a vacuum to pull the lens into position, and then it will spin the lens and spray it with a coating material. There are a few different types of coating materials and machines, but one of the following ways is widely used: PECVD (Plasma Enhanced Chemical Vapor Deposition) or PVD (Physical Vapor Deposition) Coating.
Quality assurance (QA) is the part of the production process that checks whether the lenses produced meet the required standards. It is also the process that determines if the lenses are defective or not. The process involved in quality assurance is very simple. The first step is to check if the lenses are produced according to the specifications. The next step is to check if the lenses meet the requirements of the customer. The final step is to check if the lenses are defect-free or not.
This means inserting the ready lenses into the rims, and it is usually done by an optician. It is of utter importance to be precise to ensure the best correction of the patient’s vision – and here the Tomey micrometers will be just appropriate.
3 Things to Consider when Processing Lenses on Tomey Edger
A lens is a device used to focus light or any other kind of electromagnetic radiation, as well as diverging or converging the light rays. It is made from a piece of cut glass or plastic. The main purpose of a lens is to make it possible for the patient to see things that are not visible for them due to poor eyesight. Here are the top three things to consider when processing lenses on Tomey Edger.
Most people don’t stop to think about how their prescription lenses change the way they view the world. This is particularly true for eyeglasses, which are so often seen as a tool for correcting vision rather than a tool for improving life quality. The fact is, the kind of lenses chosen for the glasses are a huge part of the patient’s optical experience. In fact, the unsuitable lenses can make it harder to see clearly and can even worsen the patient’s eyesight. The good news is that eye care professionals really do have a lot of freedom to choose the lenses that work best for their clients.
The system needs to know the preferences of the client and the requirements of the optician. This is one of the most important steps in the whole process because it will determine how the rest of the procedure goes.
Sometimes you need to explain to your patients that when choosing their lenses, they should keep in mind that they are not just buying the lens, but paying for the services of the additional equipment that is needed to process their lenses. Each lens has different equipment required to process it. For example, a lens that is 50 mm will need a different set of equipment than a lens that is 100 mm. The same goes for a lens that is 400 mm.
Make sure of your good online Reviews
Lens processing is not a very easy thing to do, and to assure your customers and make them choose your services, you should have positive online reviews left by other customers. By reading these reviews, the customers can understand that you are a professional with top-notch equipment such as Tomey offers.