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US 2018/0122418 A1Published application
Ultrasonic molding of thin wall optical components
AssigneeJohnson & Johnson Vision Care, Inc.
InventorsVictor Lust, Jeffrey Miller, David Porter, Praveen Pandojirao, Randall B. Pugh
Life of this patent
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Abstract
An ultrasonic molding device for molding thin-walled optical components which includes an ultrasonic assembly and a plunger assembly for melting thermoplastic material and injecting it into a mold under reduced pressure conditions.
Claims35
An ultrasonic molding device for molding optical components, comprising:
- a first mold block including a first mold insert having a first mold cavity defining portion, a horn chamber, and a first passageway formed along a mating surface of the first mold block between the horn chamber and the first mold cavity defining portion;
- a second mold block including a second mold insert having a second mold cavity defining portion configured to operatively engage the first mold cavity defining portion, a plunger chamber configured to be axially aligned with the horn chamber, and a second passageway formed in a mating surface of the second mold block between the plunger chamber and the second mold cavity defining portion;
- an ultrasonic assembly having a vibration element configured to be positioned in the horn chamber and switched between an inactive and active state, and
- a plunger assembly comprising a plunger pin configured to reciprocate within the plunger chamber,
- wherein the molding device is movable between an open and closed position, wherein in the closed position, the mating surface of the first mold block engages the mating surface of the second mold block such that the first mold cavity defining portion and the second mold cavity defining portion cooperatively form a mold cavity configured to form an optical component, the horn chamber and plunger chamber axially align to form a melting chamber, and the first passageway and the second passageway longitudinally align forming a runner configured to deliver molten thermoplastic material from the melting chamber to the mold cavity.
2 more elements
A method of forming an optical component, comprising:
- (a) providing a molding device comprising:
- a first mold block including a first mold insert having a first mold cavity defining portion, a horn chamber configured to receive an ultrasonic assembly, and a first passageway formed along a mating surface of the first mold block,
- a second mold block including a second mold insert having a second mold cavity defining portion, a plunger chamber configured to receive a plunger assembly, a second passageway formed along a mating surface of the second mold block configured to align with the first passageway,
- an ultrasonic assembly including a vibration element, configured to move axially in the horn chamber, and
- a plunger assembly including a plunger pin configured to move axially in the plunger chamber, and a material feeder capable of providing thermoplastic material to the horn chamber;
- (b) placing the first mold block in engagement with the second mold block such that the first mold cavity defining portion and second mold cavity defining portion cooperatively form a mold cavity, the plunger chamber and horn chamber are aligned defining a melting chamber therein, and the first passageway and second passageway are aligned to form a runner between the mold cavity and the melting chamber;
- (c) introducing solid thermoplastic material from the material feeder into the melting chamber;
- (d) moving the vibration element into position in the horn chamber such that a terminal end portion of the vibration element is located adjacent to the thermoplastic material in the melting chamber;
- (e) activating the ultrasonic assembly such that vibrational energy of a predetermined magnitude melts the thermoplastic material;
- (f) moving the plunger pin in the plunger chamber towards the vibration element thereby expelling molten thermoplastic material through the runner into the mold cavity;
- (g) curing the material in the mold cavity thereby forming an optical component;
- and
- (h) demolding the optical component from the mold cavity.
10 more elements
The method of forming an optical component of 25, wherein the runner has a length in the range of from about 8 mm to about 20 mm.
Dependencies are inferred from the claim text.