Cryogenic Lens Blank Mandrel for Precise Intraocular Lens Machining
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional techniques for machining intraocular lenses, particularly hydrophobic materials, face challenges in ensuring accurate alignment and centering of the lens blank during the milling process, especially when using cryogenic methods.
Innovation Solution
A mandrel with a central axis and a lens blank holding section featuring projections and a ring to support the lens blank, where a liquid is frozen to provide stability during machining, ensuring precise alignment and centering of the lens blank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cryogenic methods are used to machine hydrophobic lens blanks, then the lens material can be machined, but accurate alignment and centering of the lens blank becomes difficult to achieve
Solution Approach 1:
The mandrel is pre-cooled to cryogenic temperatures before the lens blank is mounted. The liquid (water) is frozen in advance within the mandrel's central cavity to create a stable, pre-formed support structure. This preliminary preparation ensures that when the lens blank is mounted and machined, the alignment and centering are maintained accurately throughout the machining process, resolving the contradiction between machinability and manufacturing precision.
2Device complexity
If the lens blank is held directly on the mandrel surface, then the structure is simple, but the lens blank cannot be held securely during machining
Solution Approach 1:
A layer of frozen liquid (ice) is introduced as an intermediary between the mandrel surface and the lens blank. This frozen intermediary provides a secure bonding interface that holds the lens blank firmly in place during machining operations. The ice layer acts as a mediator that transfers and distributes mechanical forces, ensuring reliable holding without requiring complex clamping mechanisms, thus maintaining structural simplicity while improving holding stability.
3Reliability
If wax is used to hold the lens blank, then the blank is held in place, but the wax interferes with subsequent machining operations
Solution Approach 1:
The holding medium is changed from wax to frozen water by altering the physical state and material properties. Water is introduced as a liquid that can be easily removed or melted away, unlike wax which requires solvent removal. By freezing water to hold the lens blank and then allowing it to melt during or after machining, the holding capability is maintained during mounting while machining accessibility is improved, as no residue interferes with the machining operations.
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
The mandrel maintains precise alignment and stability of the lens blank, facilitating accurate machining and reducing errors in the manufacturing process, especially for hydrophobic materials, and allows for prolonged storage and transportation of partially completed lenses.
Implementation Method 1
The liquid is frozen to support the lens blank as it is milled and/or machined
Implementation Method 2
a mandrel for holding and positioning an intraocular lens blank during manufacturing
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4C
AI summary
A mandrel (100) configured for holding and positioning an intraocular lens blank (204, 404) during manufacturing includes a shank portion (150) having a central axis (X) and a lens blank holding section (105) configured to hold the lens blank (204, 404). The holding section (105) includes a central cavity (110) formed concentrically with the central axis (X) of the mandrel (100). Projections (112) are formed on a surface (120) of the central cavity (110) and are configured to support a first surface (208, 408) of the lens blank (204, 404) at a fixed distance from the surface of the central cavity. A ring (200) fits within a peripheral portion (122) of the central cavity (110) to hold a second opposing surface (210, 410) of the lens blank (204, 404). A method for making an intraocular lens (612) using the mandrel (100) includes filling the space (405) formed under the first surface (208, 408) of the lens with a liquid, such as water (502), freezing the liquid (607), and then machining and/or milling the second surface (210, 410) of the lens blank (204, 404).