Eyeglass Lens Processing Torque Control
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Solution Overview
Problem
Existing eyeglass lens processing apparatuses face challenges in preventing 'axial displacement' during the rough-grinding of water-repellent lenses, where the slippery surface causes the cup to slip, leading to misalignment and torque issues, and previous solutions either result in prolonged processing times or excessive load torque.
Innovation Solution
An eyeglass lens processing apparatus that includes a motor for rotating the lens chuck shaft, an axis-to-axis distance changing unit, a calculation unit that determines the cutting depth based on the lens thickness and surface curve configurations, and a control unit that adjusts the axis-to-axis distance to maintain constant torque, ensuring precise processing without lengthening the processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cutting depth is increased to reduce processing time, then productivity is improved, but the load torque rapidly exceeds the tolerance and causes axial displacement
Solution Approach 1:
The patent applies dynamics by making the cutting depth variable rather than constant. The control unit dynamically adjusts the cutting depth based on the detected lens thickness at each position, allowing deeper cuts in thinner regions and shallower cuts in thicker regions, thereby maintaining constant torque while improving overall processing efficiency
Solution Approach 2:
The patent changes the parameter of cutting depth from a fixed value to a variable that depends on lens thickness. By calculating and adjusting the cutting depth for each position based on measured thickness data, the system maintains torque within tolerance limits while optimizing material removal rate across the entire lens
2Manufacturing precision
If the cutting depth is kept constant to maintain stable processing, then manufacturing precision is improved, but the processing time is lengthened due to conservative depth settings
Solution Approach 1:
The system transitions from static constant cutting depth to dynamic variable cutting depth. The control unit continuously adjusts the cutting depth parameter based on real-time lens thickness measurements, enabling precision control adapted to each position's specific requirements rather than applying a uniform conservative depth throughout
Solution Approach 2:
The cutting depth parameter is changed from a constant value to a position-dependent variable. By calculating optimal cutting depth for each location based on lens thickness, the system achieves both precision (by maintaining torque limits) and efficiency (by maximizing material removal where safe)
3Reliability
If the cup attaching position slips on water-repellent lens surface, then the lens becomes difficult to hold, but increasing holding force may damage the slippery surface
Solution Approach 1:
The patent replaces mechanical holding methods (relying on friction between cup and lens surface) with a measurement and control-based approach. By measuring lens thickness and calculating optimal cutting parameters, the system compensates for the slippery surface issue through intelligent control rather than increased mechanical holding force
Solution Approach 2:
The system uses feedback from lens thickness measurements to adjust cutting depth and torque control. This feedback loop allows the system to adapt to the specific conditions of water-repellent lenses, maintaining stable processing without requiring enhanced mechanical holding that could damage the surface
Data Source
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AI summary
An eyeglass lens processing apparatus includes: a lens rotation unit rotating a lens; a processing tool rotation unit processing the lens; an axis-to-axis distance changing unit for changing an axis-to-axis distance between the chuck shaft and the processing tool rotation shaft; a lens surface configuration acquiring unit which acquires a front surface curve configuration and a rear surface curve configuration of the lens; a lens outer diameter acquiring unit which acquires an outer diameter of a lens; a calculation unit which calculates a thickness of the lens and calculates a cutting depth of the lens, so that torque applied onto the chuck shaft in rough processing becomes substantially constant, based on the calculated lens thickness and a processing distance from the rotation center of the lens; and a control unit which controls the axis-to-axis distance changing unit in accordance with the calculated cutting depth and for rough processing the lens.