METHOD FOR THE INJECTION MOULDING OF AN OPTICAL ELEMENT MADE FROM SYNTHETIC THERMOPLASTIC MATERIAL

摘要

For each lens molding cycle, the method comprises the following steps:raising the wall of the mold cavity to a heating temperature higher than or equal to the molding temperature of said material;filling the molding cavity with said material;at the end of filling, increasing the pressure of said material introduced in this way into the molding cavity up to a compacting pressure; andbringing the wall of the molding cavity to a cooling temperature to cool said molded material down to an unmolding temperature below its molding temperature, said cooling temperature being lower than said unmolding temperature.The molding cavity begins to be filled with said material before the heating temperature has been reached. Once both the compacting pressure of said material and the heating temperature of the molding cavity wall have been reached, they are both maintained for a given length of time.