Multi-color lens assembly injection molding process and apparatus

A method of injection molding a multi-color lens assembly including a viewing side and an illumination side in a multi-station injection molding apparatus having a plurality of injection stations with respective nozzle drops including an initial injection station and a final injection station, the molding apparatus including a plurality of non-indexing halves corresponding to the plurality of injection stations and an indexing half adapted for movement through sequentially progressive injection stations, comprising the steps:

• closing the indexing half to the non-indexing half corresponding to the initial injection station;
• valve gating from the illumination side a first color transparent portion of the lens assembly including peripherally extreme features of the lens assembly that at least partially engage a plurality of interference mechanisms associated with the indexing half for obstructing release of the first color transparent portion of the lens assembly from the indexing half;
• releasing the first color transparent portion of the lens assembly from the non-indexing half corresponding to the initial injection station by stroking a plurality of ejector pins located in the corresponding non-indexing half as the indexing half is parted from the corresponding non-indexing half;
• moving the indexing half and first color transparent portion of the lens assembly to the next sequentially progressive injection station which is intermediate the initial and final injection stations and closing the indexing half to the corresponding non-indexing half;
• valve gating from the illumination side a second color transparent portion of the lens assembly abutting the first color transparent portion of the lens assembly;
• releasing the first and second color transparent portions of the lens assembly from the non-indexing half corresponding to the intermediate injection station by stroking a plurality of ejector pins located in the corresponding non-indexing half as the indexing half is parted from the corresponding non-indexing half;
• moving the indexing half and first and second color transparent portions of the lens assembly to the final injection station and closing the indexing half to the non-indexing half corresponding to the final injection station;
• valve gating from the illumination side a frame portion of the lens assembly abutting predetermined portions of the illumination side of at least one of the first and second color transparent portions to complete the multi-colored lens assembly;
• and,
• releasing the multi-colored lens assembly from the final injection station.

A multi-station injection molding apparatus for molding multi-color lens assemblies having a plurality of injection stations including initial and final injection stations, the injection stations having respective nozzle drops for molding material injection into molds comprising closed ejector and cover halves, the molding apparatus comprising:

• non-indexing ejector halves associated with each injection station, each non-indexing ejector half including respective ejector pins and nozzle drops adapted for valve gating station specific portions of the lens assembly from an illumination side thereof;
• an indexing cover half adapted for movement through sequentially progressive injection stations, said indexing cover half including edge retention heads which in an engaged position overlap peripherally extreme features of the lens assembly molded at the initial injection station to retain the lens assembly to the indexing cover half and in a disengaged position clear the peripherally extreme features of the lens assembly to liberate the lens assembly from the indexing cover half;
• ejection apparatus associated with each non-indexing ejector half for stroking respective ejector pins subsequent to molding material injection at the corresponding injection station;
• and
• positioning apparatus for establishing the edge retention heads in the engaged position prior to molding material injection at the initial station and in the disengaged position subsequent to molding material injection at the final station.