Ophthalmic Lens Shaping via Blocking Position Adjustment
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Solution Overview
Problem
Existing methods for shaping ophthalmic lenses with complex outlines, particularly those featuring zones of negative curvature, often encounter interference issues between the machining tool and the blocking support, leading to difficulties in achieving the desired outline due to the tool's diameter being smaller than the tool carrier or grindwheel.
Innovation Solution
A method involving a machining device with a blocking support and rotatable tools, where the inner cutting limit is defined to detect potential intersections, allowing for a modified blocking position to avoid interference, enabling the lens to be shaped without tool-carrier interference by repositioning the blocking support based on calculated intersections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a small-diameter tool is used to shape complex outlines with negative curvature zones, then the manufacturing precision of the desired outline is improved, but the tool may interfere with the blocking support
Solution Approach 1:
The method calculates the inner cutting limit and determines potential intersections between the tool path and blocking support before the actual shaping operation begins. By pre-computing the blocking position and adjusting it in advance to avoid interference zones, the system ensures that small-diameter tools can access complex outline regions without colliding with the blocking support, thus maintaining both precision and avoiding harmful interference.
2Adaptability or versatility
If the tool diameter is smaller than the tool carrier diameter, then the ability to shape complex outlines with negative curvature is improved, but the risk of tool carrier interference with the blocking support increases
Solution Approach 1:
The system performs preliminary calculations to determine the inner cutting limit and identifies regions where the tool carrier might interfere with the blocking support. By pre-adjusting the blocking position based on these calculations, the method enables the use of small-diameter tools for complex outlines while preventing tool carrier interference before the machining operation begins.
Solution Approach 2:
The method introduces an intermediary computational step that acts as a mediator between the tool path planning and the physical machining process. By calculating the inner cutting limit and determining safe blocking positions, this intermediary analysis allows the system to select appropriate small-diameter tools for complex shapes while automatically adjusting parameters to prevent tool carrier interference with the blocking support.
3Ease of operation
If the blocking position is kept at the initial position, then the ease of operation is improved, but the tool may intersect with the inner cutting limit causing interference
Solution Approach 1:
The system performs self-service by automatically calculating the inner cutting limit and determining the appropriate blocking position based on the desired outline and tool dimensions. This automated calculation eliminates the need for manual intervention to adjust the blocking position, maintaining ease of operation while preventing tool interference with the blocking support through intelligent, self-determined position adjustment.
Data Source
AI summary
A method of shaping an ophthalmic lens to have a desired outline with a machining device including a blocking support for the ophthalmic lens and at least one first machining tool, the method includes:obtaining an inner cutting limit for the first machining tool;defining an initial blocking position for the ophthalmic lens and its desired outline;calculating whether at least a portion of the desired outline presents a non-zero intersection with the inner cutting limit;defining as the final blocking position either the unchanged initial blocking position if the calculated intersection is zero, or else a blocking position that is modified relative to the initial blocking position so that the desired outline as repositioned using the modified blocking position does not present an intersection with the inner cutting limit associated with the first tool; andblocking and shaping the ophthalmic lens with the desired outline.