Helical Lens Drilling Process for Ophthalmic Tools

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Solution Overview

Problem

Existing methods for drilling ophthalmic lenses are time-consuming and prone to overheating and breakage, especially when drilling through thick lenses with difficult-to-machine materials, leading to prolonged execution times and potential lens damage.

Innovation Solution

A drilling process that determines control setpoints for transverse displacement and advance based on the lens's thickness, material, and drilling tool characteristics, using a helical or pseudo-helical trajectory with varying axial and transverse movements to efficiently drill holes of different shapes and sizes with a single tool, reducing the number of passes and minimizing tool breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If simple advance drilling method is used, then the drilling process is simple, but the execution time is long and the lens may overheat or break

Engineering Contradiction:

Improvedrilling execution timeVSAvoidlens integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies a helical trajectory for the drilling tool instead of a straight rectilinear path. The tool tip follows a helical path during drilling, which allows for continuous transverse movement while advancing through the lens material. This curved trajectory distributes the cutting action along a longer path, reducing heat concentration and mechanical stress at any single point, thereby preventing lens overheating and breakage while maintaining efficient drilling speed.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent implements dynamic control of the drilling tool by continuously varying its transverse position according to a helical pattern during the drilling process. The tool is not stationary in the transverse plane but moves dynamically along a helical path, which optimizes the cutting action throughout the drilling operation. This dynamic movement ensures consistent chip evacuation and heat distribution, improving both drilling speed and lens integrity.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If bypass drilling method is used to drill different sizes and shapes, then the same tool can be used, but the execution time increases significantly

Engineering Contradiction:

Improvetool versatilityVSAvoiddrilling execution time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The helical trajectory enables a single drilling tool to efficiently create holes of various sizes and shapes without requiring multiple tools or sequential operations. By controlling the helical path parameters (radius, pitch, and number of turns), the same tool can adapt to different hole specifications, combining versatility with speed.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The helical drilling method allows for continuous drilling action in a single pass without the need for alternating between advancement and transverse displacement steps. The tool continuously moves along the helical path, maintaining cutting engagement throughout the operation, which eliminates idle time and significantly reduces total execution time compared to bypass drilling.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If drilling speed is reduced to avoid tool breakage, then tool reliability improves, but the drilling execution time increases

Engineering Contradiction:

Improvetool durabilityVSAvoiddrilling execution time

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The helical trajectory distributes the cutting forces along a longer, curved path rather than concentrating them in a straight line. This reduces the instantaneous load on the tool at any given point, allowing the tool to operate at higher speeds without risking breakage. The continuous transverse movement prevents excessive force buildup that would occur in traditional straight drilling.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The dynamic helical movement of the tool creates optimal cutting conditions throughout the drilling process, maintaining consistent engagement and chip evacuation. This dynamic action prevents the tool from experiencing excessive static loads that could cause breakage, enabling sustained high-speed operation while protecting tool integrity.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentEP2976197B1Lens drilling process along an helicoidal trajectory and device to carry-out such a process

Publication Date: 2018.05.09 ESSILOR INTERNATIONAL(COMPAGNIE GENERALE D OPTIQUE)

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AI summary

The invention concerns a method for drilling an ophthalmic lens (10) comprising the following steps: - memorising the desired shape and dimensions of a drill hole (701; 702; 703) to be drilled in the ophthalmic lens (10) and the position of the opening of this drill hole on one of the faces (11, 12) of the ophthalmic lens, - positioning a drilling tool (80) facing the memorised position of the hole (701; 702; 703) to be drilled, - determining a control setpoint for the transverse movement and axial advance of the drilling tool (80), and, - drilling the ophthalmic lens according to said control setpoint. According to the invention, the control setpoint for the transverse movement and axial advance of the drilling tool (80) forces the point of this drilling tool, on at least one drilling run, to follow a helical or pseudohelical trajectory (H; H1, H2), depending on the desired shape and dimensions of the drill hole. The invention also concerns an associated drilling device.