Abstract:
The invention relates to a mould and a method for the hot forming of a thermoplastic optical lens. The inventive mould consists of two dies (1, 2) which are mounted in a hollow shaft (3), so as to slide along the axis (6) thereof, and which comprise opposing forming surfaces (4, 5). The two dies (1, 2) and the shaft (3) are provided with intrinsic heat transfer means. The inventive method comprises the following steps, consisting in: placing a paraison or preform (P) of said thermoplastic material between the two dies (1, 2) and enclosing all of the latter inside the shaft (3); heating the dies (1, 2) and the shaft (3) to a forming temperature, using the intrinsic heat transfer means thereof (15, 16, 19, 20); bringing the dies (1, 2) closer together, in order to form the material by means of plastic deformation, until a pre-determined relative position is reached, said position corresponding to the desired thickness of the lens; cooling the dies (1, 2) and the shaft (3) to a stripping temperature, using the intrinsic heat transfer means thereof (15, 16, 19, 20); and extracting the finished lens (L) from the mould.
Abstract:
A method for in-mold coating of an injection molded thermoplastic lens that resides in an injection molding machine oriented to a horizontal parting line(116). An optical lens(
Abstract:
The invention relates to a mould half-block comprising at least one mould cavity which is defined transversely by the useful surface of a shell. The aforementioned shell, which is provided with intrinsic, dual-purpose heat transfer means (heating and cooling), comprises: a base bearing all of the heat transfer means of the shell; and a removable insert which is mounted on the base and which bears said useful surface. The insert comprises no intrinsic heat transfer means and is thermally regulated solely by means of heat transfer with said base. Moreover, the insert, which is in the form of a cap, covers at least a head portion of the base and the heat transfer means of the base determine the head portion of the base that is covered by the insert.
Abstract:
The invention relates to a method for the injection moulding of an optical element made from synthetic thermoplastic material. For each lens moulding cycle, the method comprises the following steps: the wall of the mould cavity is heated to a heating temperature which is greater than or equal to the moulding temperature of the material; the mould cavity is filled with said material; once filled, the pressure of the material thus introduced into the mould cavity is increased to a compaction pressure; the wall of the mould cavity is cooled to a cooling temperature in order to cool the moulded material to a stripping temperature which is lower than the melting temperature thereof, said cooling temperature being lower than the aforementioned stripping temperature. The filling of the mould cavity with said material is started before the heating temperature has been reached. When both the compaction pressure of said material and the heating temperature of the mould cavity wall have been reached, they are maintained for a given time.
Abstract:
A method to produce in-mold coated lenses, and the coated lenses produced by the method. A cliche (80a) with a measured amount of thermoset acrylate-based coating solution is provided on, or adjacent to, the parting line of an injection molding machine. An inflatable silicone bladder (70b) is dipped into the cliche to pickup a thin film of coating. The bladder is transported along a vertical axis or plane or other path to press the coating against the heated mold insert (46a). The bladder pauses while the coating pre-cures and the bladder is peeled off, leaving the coating on the mold insert. The mold is closed and a thermoplastic resin is injected into the mold cavity to form a coated ophthalmic lens.
Abstract:
A method of in-mold coating utilizing an injection molding machine oriented to a horizontal parting line. At the beginning of the cycle the mold opens and a charge of liquid coating solution is deposited onto the lower mold insert. A ophthalmic wafer is deposited on the coating to spread it across the insert surface. The mold is closed and a pre-cure phase elapses before the thermoplastic resin is injected into the mold cavity above the wafer. The process provides coated and functionally enhanced lenses upon ejection from the molding machine.
Abstract:
The invention relates to a mould and a method for the hot forming of a thermoplastic optical lens. The inventive mould consists of two dies (1, 2) which are mounted in a hollow shaft (3), so as to slide along the axis (6) thereof, and which comprise opposing forming surfaces (4, 5). The two dies (1, 2) and the shaft (3) are provided with intrinsic heat transfer means. The inventive method comprises the following steps, consisting in: placing a paraison or preform (P) of said thermoplastic material between the two dies (1, 2) and enclosing all of the latter inside the shaft (3); heating the dies (1, 2) and the shaft (3) to a forming temperature, using the intrinsic heat transfer means thereof (15, 16, 19, 20); bringing the dies (1, 2) closer together, in order to form the material by means of plastic deformation, until a pre-determined relative position is reached, said position corresponding to the desired thickness of the lens; cooling the dies (1, 2) and the shaft (3) to a stripping temperature, using the intrinsic heat transfer means thereof (15, 16, 19, 20); and extracting the finished lens (L) from the mould.