Ophthalmic Lens Mandrel Surface Layout for Wax-Controlled Alignment
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Solution Overview
Problem
Existing mandrel systems for machining ophthalmic lenses face challenges in accurately positioning the lens blanks, leading to machining errors and optical performance issues due to wax residue, especially when handling complex lens assemblies with optical components.
Innovation Solution
A mandrel design featuring a planar surface region and drainage channel to accurately locate the lens blank, reducing wax overflow and misalignment, and a kit of parts with interchangeable center-pieces for various lens shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a block of wax is provided on the front surface of the mandrel to hold the lens blank, then the lens blank can be mounted on the mandrel during machining, but accurate placement of the lens blank and consistent wax thickness are difficult to obtain, leading to machining errors
Solution Approach 1:
The front surface of the mandrel is segmented into distinct functional zones: a curved surface region for receiving the lens blank, a planar surface region for stable contact, and a drainage channel region for wax management. This segmentation allows each region to perform its specific function optimally, ensuring both ease of mounting and high placement accuracy.
Solution Approach 2:
The drainage channel acts as an intermediary structure that manages the wax between the curved surface region and the planar surface region. It controls wax flow to prevent contamination of the planar surface, thereby maintaining both the ease of mounting (through adequate wax) and the precision (through clean contact surfaces).
2Ease of operation
If a block of wax is used to hold the lens blank on the mandrel, then the lens blank can be secured during machining, but wax residue remains on the lens surface producing a hazy or cloudy effect that impacts optical performance
Solution Approach 1:
The drainage channel extracts excess wax from the curved surface region where it would otherwise remain in contact with the lens blank. By providing a dedicated pathway for wax to drain away, the system removes the harmful element (excess wax) while preserving the useful function (securing the lens blank).
Solution Approach 2:
The drainage channel converts the potentially harmful excess wax into a beneficial controlled flow. The wax that would otherwise create residue and optical defects is redirected through the drainage channel, transforming from a harmful contaminant into a controlled element that maintains lens security without compromising optical quality.
3Manufacturing precision
If more accurate machining techniques are applied to ophthalmic lens assemblies with optical components, then the required dimensions and precision can be achieved, but the complexity and cost of the machining process increases
Solution Approach 1:
The mandrel design performs preliminary positioning actions before the machining process begins. The curved surface region receives and pre-positions the lens blank in the correct orientation and location, ensuring that subsequent accurate machining can be performed without requiring complex positioning mechanisms or multi-step alignment procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves accuracy and reduces machining errors, minimizing wax residue and enhancing optical performance by ensuring precise alignment and efficient wax management during the machining process.
Implementation Method 1
a drainage channel extending around a boundary between the curved surface region and the planar surface region such that excess wax on the curved surface region is directed away from the planar surface region
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3~4
AI summary
A mandrel (1) for holding an ophthalmic lens member blank (16) during machining is disclosed. The mandrel (1) has a front surface (6) for receiving an ophthalmic lens member blank (16) to be machined. The front surface (6) comprises a planar surface region (10); a curved surface region (8); and a drainage channel (12) located between the curved surface region (8) and the planar surface region (10) such that wax applied to the curved surface region (8) flows into the drainage channel (12). A kit of parts comprising such a mandrel (1), a method of mounting an ophthalmic lens member blank (16) for machining, a method of machining an ophthalmic lens member blank (16), an ophthalmic lens produced using the apparatus and a batch of such lenses are also disclosed.