Molding Process: - Molding the lens can be done in several different ways. The lenses first developed in Prague spin-cast. Three different liquid emptied into open molds rotation. The outer curvature of the lens is formed by the mold, and the curvature in the interior are formed according to the speed of rotation of the mold. The centrifugal force rotates the mold resulted in polymerization of the fluid so that the molecular chains attached to the form of plastic requires hydrophilic. A more reliable mass production of colour contact lenses is the method of injection molding. In injection molding, molten plastic is injected into the mold under pressure. Then the lens is removed from the mold and cooled. The goal is to finish on a lathe then. It is also possible to produce lenses completely through molding, there, no need to cut around. This is a recent development, made possible thanks to highly automated, computer controlled production mod.
Lathe process:- The initial formation of the lens can also be done by cutting on a lathe. At first a blank is prepared. The target is a circle only a little bigger than the dimension of the finished lens. This can be cut from a plastic rod, or the seal of a plastic sheet. Then, blank is put in a steel button with a slump of molten wax. The button is then turned on a lathe, which begins to rotate at high speed. A cutting tool, which can be a diamond or a laser, it cuts concave in the blank to form the CPC. Indicators on the lathe to measure the depth of cuts to guide the operator of the lens.
The button holding the target is then moved to a polishing appliance. The polishing machine has a blank against a Lapper, a spinning disk covered with an abrasive compound. The shapes of the Lapp coincide with the CPC lente. The polishing machine the blank rotates in one direction and Lapper on the other. It also moves the blank space in small figure of eight movements. The abrasion polishes the surface of the lens.
The lens is mounted on a polished steel shaft called an arbor. The end of the roundabout has been ground to match the CPC so that the lens will adjust the shaft. The garden has been installed on a lathe, and the operator makes cuts convex lens to form the curve of other great, the CAC. Now this side of the lens is polished, and Lapper has been modified to fit the convex CAC. When the second side of the lens is polished, the lens is considered semi-finished products
Finishing Process:- The lens requires several corners to the ground before the lens fits exactly in the eye of the patient. The final curves are the anterior and posterior peripheral curves and curves before and after intermediate, which govern the shape of the lens closest and next closest to the edge. The lens is mounted on an arbor again by suction or double-sided tape. The garden has been installed on the lathe or milling machine. These cut surfaces can be ground with sandpaper or cut with a razor. The diameter of the lens can also be arranged at this time.