CNC Lathe Rotational Control for Optical Insert Positioning
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Solution Overview
Problem
Existing methods for manufacturing ophthalmic devices like contact lenses and intraocular lenses lack precise rotational positioning of optically defined surfaces during the manufacturing process, which is crucial for achieving the desired optical effects.
Innovation Solution
A method for manufacturing a cylindrical optical insert for an injection mold using a CNC-controlled lathe with a clamping head and tool displacement, enabling accurate formation of optically defined surfaces and positioning surfaces, such as stop surfaces or pin recesses, to ensure precise rotational orientation of the optical insert within the mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods are used for optical inserts, then manufacturing simplicity is maintained, but rotational positioning precision of optically defined surfaces deteriorates
Solution Approach 1:
The method incorporates preliminary rotational positioning of the optical insert in the lathe's clamping head before machining the optically defined surface. The clamping head is rotated to a predetermined angular position, and the insert is secured in this positioned state, ensuring that subsequent machining operations occur at the correct rotational orientation. This preliminary positioning action resolves the contradiction by establishing precise rotational alignment before the actual optical surface creation.
Solution Approach 2:
The invention replaces conventional mechanical positioning methods with a CNC-controlled lathe system that uses programmable rotational positioning of the clamping head. Instead of relying on manual alignment or mechanical fixtures, the system uses computer-controlled rotation to achieve precise angular positioning, thereby improving rotational positioning precision while managing process complexity through automation.
2Manufacturing precision
If CNC-controlled lathe with rotational control is used, then rotational positioning accuracy is improved, but manufacturing process complexity increases
Solution Approach 1:
The clamping head of the lathe is designed with multi-functionality, serving both as a securing mechanism for the optical insert and as a rotational positioning device. The same clamping head that holds the insert can be rotated to precise angular positions, combining two functions (securing and positioning) into one component. This reduces overall process complexity while maintaining high rotational positioning accuracy.
Solution Approach 2:
The method enables the optical insert itself to define its own rotational orientation through the positioning surfaces and stops that are machined during the same setup. The insert's own geometry, created by the CNC lathe, serves as the reference for its rotational positioning in the injection mold, eliminating the need for separate external positioning fixtures or procedures.
Data Source
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AI summary
Method for manufacturing a cylindrical optical insert (64) for an injection mold (50) for manufacturing an ophthalmic device (12, 20, 250, 260). The method comprises manufacturing an optically accurately defined surface (66, 66') of the optical insert (64) on a lathe (200) with a CNC control, the lathe being provided with a rotatable clamping head (202) whose rotational position is controllable and in which the optical insert (64) is in a clamped position during the manufacture of the optical surface, whereby a stop surface or a pin recess (106) of the optical insert (64) is provided with a cutter or a drill (206) while the optical insert is in the clamped position in the clamping head, whereby the CNC control defines the position of the stop surface or the pin recess (106) with respect to the optically accurately defined surface (66) through accurate rotational control of the clamping head for positioning the optical insert with respect to the cutter or drill.