Patent ID: 7854865

Claim:
A method for injection molding thin lenses with a coining operation, the method comprising the steps of: providing an injection molding machine with two mold halves that are opened and closed by a mold clamp along a parting line, wherein each mold half includes a sleeve securely fixed to the respective mold half and a mold insert secured in a fixed position within the sleeve, wherein the insert, sleeve and respective mold half remain securely fixed in position relative to one another during the entire process; closing the mold halves with the mold clamp to a predetermined clamp force F c that is less than a net integrated force exerted on the mold inserts during injection, whereby the closed inserts define a cavity; injecting molding material into the cavity via at least one gate so that the force exerted on the inserts by the molding material is transferred via the securely fixed position of the inserts to the mold halves to force the mold halves open along the parting line of the mold thereby reducing flow resistance and allowing the material to reach portions of the mold insert periphery; and coining a lens having a section less than 1 mm thick as the net integrated force on the inserts subsides and the mold halves close back down.