Lens Processing Torque Control for Axis Deviation
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Solution Overview
Problem
Eyeglass lens processing apparatuses face axis deviation issues due to excessive load exceeding the holding force, particularly in liquid-repellent lenses with slippery surfaces, leading to rotational deviations during high-speed processing.
Innovation Solution
An eyeglass lens processing apparatus equipped with a lens rotating unit, axis-to-axis distance changing unit, torque detector, torque level setting unit, and driving controller to adjust rotational speed and processing pressure, ensuring the detected torque remains below a set allowable level, thereby preventing axis deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed processing is performed with a rotating processing tool, then productivity is improved, but axis deviation occurs due to excessive load exceeding the holding force of the lens
Solution Approach 1:
The holding force is made dynamically adjustable through a variable holding force generating mechanism. The mechanism includes a holder that can be positioned at different distances from the lens rotation axis, allowing the holding force to be varied in response to detected torque levels. When excessive torque is detected indicating impending axis deviation, the holder distance is adjusted to reduce the holding force and prevent further deviation, thus maintaining manufacturing precision while enabling high-speed processing.
Solution Approach 2:
A torque detection mechanism continuously monitors the torque applied to the lens during high-speed processing. This feedback information is used by the control system to adjust the holder distance and thereby the holding force in real-time. The feedback loop ensures that when torque exceeds a predetermined threshold, the holding force is automatically adjusted to prevent axis deviation, resolving the contradiction between maintaining high processing speed and preventing precision loss.
2Manufacturing precision
If the holding force is increased to prevent axis deviation, then manufacturing precision is improved, but the complexity of the device increases due to additional control mechanisms
Solution Approach 1:
The invention changes the parameter of holder distance from the lens rotation axis to control the holding force. By varying this geometric parameter, the holding force is adjusted without requiring complex mechanical structures. The variable holding force generating mechanism achieves precise control of holding force through simple positional adjustment of the holder, thereby preventing axis deviation while minimizing device complexity.
Solution Approach 2:
The torque detection mechanism automatically detects when excessive torque is applied and triggers the holder distance adjustment without requiring external intervention. The system serves itself by using the detected torque information to automatically correct the holding force, reducing the need for complex external control systems while maintaining manufacturing precision.
3Device complexity
If a fixed holding force is used, then the device complexity is reduced, but axis deviation occurs in liquid-repellent lenses with slippery surfaces
Solution Approach 1:
The invention transitions from a fixed holding force system to a dynamic one where the holding force automatically adapts to the lens surface properties. The variable holding force generating mechanism allows the holder distance to be adjusted based on detected torque levels, enabling the system to maintain appropriate holding force for slippery liquid-repellent lenses without requiring complex predetermined settings for different lens types.
Solution Approach 2:
The torque detection mechanism provides continuous feedback on the actual holding effectiveness. For liquid-repellent lenses with slippery surfaces that are prone to axis deviation, the feedback signal triggers automatic adjustment of the holder distance to optimize the holding force. This feedback-based adaptation resolves the contradiction by maintaining manufacturing precision while keeping the control mechanism relatively simple.
Data Source
AI summary
An eyeglass lens processing apparatus includes: a lens rotating unit having lens chucking shafts which hold an eyeglass lens, and a first motor which rotates the chucking shafts; an axis-to-axis distance changing unit having a second motor which changes an axis-to-axis distance between a center axis of rotation of a processing tool which processes a periphery of the lens and a center axis of rotation of the chucking shafts; a torque detector which directly or indirectly detects torque transmitted to the chucking shafts; a torque level setting unit which variably sets an allowable torque level; and a driving controller which controls at least one of driving of the first motor and driving of the second motor to adjust at least one of a rotational speed of the chucking shafts and a processing pressure of the lens so that the torque falls below the allowable torque level.