Patent ID: 11938694
Assignee: ESSILOR INTERNATIONAL
Field: Other special machines (Mechanical engineering)
Classification: CPC B  G | IPC B  G

Claim 7:
8. An injection molding system for producing an injection molded optical article, the injection molding system comprising:
a mold having a mold cavity for receiving a thermoplastic material, the mold cavity including a Fresnel surface;
a heat source in thermal communication with the mold; and
a processor configured to successively perform:
(i) controlling the heat source to set a surface temperature of the mold cavity to a cooling temperature at least 5° F. to 150° F. lower than a softening temperature of the thermoplastic material before an injection of said thermoplastic material in the mold cavity;
(ii) after the injection of said thermoplastic material in the mold cavity, controlling the heat source to raise the surface temperature of the mold cavity to a heating temperature at least 20° F. higher than the cooling temperature; and
(iii) controlling the heat source to lower a temperature of the mold cavity to the cooling temperature;, wherein the thermoplastic material is a thermoplastic polyurethane (TPU), polyvinylchloride (PVC), or thermoplastic elastomer (TPE).