Contact lenses are very popular today. They are made from a polymer with cut button. To create contact lens, the manufacturer needs a computer to guide them in shaping the inside of the contact according to the prescription. Then, any imperfection which may come to the lens is removed by polishing it with the abrasive paste. Any imperfection in the lens can cause the vision to blur so that it is not comfortable to use.
Then, the thickness of the lens is measured to make sure that it is in correct size. Then, it will be coated with the wax to make the outside part of the lens be molded for the desired shape. If the outside part has already been shaped, the wax is removed by using ultrasound. Then, the rims and outer surface of the lens are polished for better result. Hereafter, the lens is put in a saline solution for about 24 hours so that the lens will absorb adequate liquid until it is flexible and soft.
The last step is to make sure that the lens has met what the prescription say. Also, it is checked to see if the lens is able to refract the light correctly. Then, it is sealed in a bottle with saline solution. The container has been sterilized so that it can last up to 7 years.
In addition, contact lens can be made through a process which is called as the spin casting. It uses mold which is filled with the liquid monomer. Monomers are popularly known as the tiny molecules with different characteristics so that they can be combined in various ways for making polymers. To create the lens, the monomer is polymerized through the rotating mold. Different speed of the mold’s rotation can result different quality. In this process, the lens can be through some finishing process including polishing, check, sterilization and packaging.
Instead, contact lens can be made through an injection molding process. It involves a mold which is made of two halves. Those halves are put together. Then, the polymer of the lens is injected into that mold under pressure. Then, the mold is removed and cooled. For the last step, the lenses are polished, checked, sterilized and then packaged.
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Injection molding process can be used to create some other daily equipment, especially from plastic. With special machine such as blow molding machine, the manufacturer can easily form the plastic for the final products. For more information about it, you can read injection molding equipment.