Eccentric Chuck for Monolithic Lens Array Machining
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Solution Overview
Problem
Existing positioning and indexing solutions for machine tools are not suitable for ultra-precision machining of monolithic lens arrays, as they require rebalancing after each displacement and struggle with maintaining accuracy and speed during high-speed rotation, especially when machining steep slopes and freeform surfaces.
Innovation Solution
A chuck with eccentrically mounted rotatable plates and balancing means that allows precise positioning of objects with respect to the main axis of rotation without rebalancing, using a holding mechanism and actuating mechanism to angularly displace the plates, ensuring the principal axis of inertia aligns with the spindle axis, enabling dynamic micrometer accuracy and continuous machining without stopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional diamond turning with substrate shifting is used, then lens-to-lens registration accuracy can be achieved, but production time increases significantly
Solution Approach 1:
The invention employs dynamic positioning of the substrate using a motor-driven indexing mechanism that rotates the substrate to precise angular positions during machining. This allows the substrate to be repositioned dynamically without stopping the machining process, enabling continuous production while maintaining lens-to-lens registration accuracy through programmed indexing positions.
Solution Approach 2:
The substrate is pre-indexed to multiple predetermined positions before machining begins. The indexing mechanism is calibrated in advance with accurate angular positions for each lens location, allowing the machining process to proceed continuously through pre-programmed positions without intermediate measurement or adjustment operations.
2Productivity
If freeform machining techniques are used to reduce production time, then productivity improves, but surface form accuracy and surface quality deteriorate
Solution Approach 1:
The invention introduces a precision indexing mechanism as an intermediary between the substrate and the machining tool. This intermediary device enables the substrate to be positioned at exact angular orientations for traditional diamond turning operations, thereby maintaining surface form accuracy while allowing continuous machining across multiple lens positions without intermediate setup operations.
3Manufacturing precision
If automatic positioning and indexing devices are added to maintain precision during rotation, then manufacturing precision can be maintained, but device complexity increases
Solution Approach 1:
The indexing mechanism is designed to be self-aligning and self-latching at predetermined positions. Once the substrate is mounted, the indexing mechanism automatically maintains precise angular positions through mechanical features such as indexed slots and detent mechanisms, eliminating the need for complex active control systems, sensors, or continuous feedback mechanisms.
4Manufacturing precision
If the substrate is repositioned for each lens position, then lens-to-lens registration can be achieved, but the need for rebalancing the work spindle increases production time
Solution Approach 1:
The substrate is pre-mounted on the indexing mechanism in a balanced position before machining begins. The indexing mechanism is designed to rotate the substrate to different angular positions while maintaining the center of gravity on the rotation axis, eliminating the need for rebalancing operations between lens positions.
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
This solution significantly reduces production time for monolithic lens arrays while maintaining high machining accuracy, allowing for the machining of complex geometries like steep slopes and freeforms without the need for rebalancing, ensuring thermal stability and minimizing positioning times.
Implementation Method 1
The chuck is arranged such that one principal axis of inertia can be arranged to substantially coincide, or even coincide, with the main axis of rotation of the work-spindle irrespective of the position, for example off-axis position, of the object mounted on the chuck
Data Source
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AI summary
A chuck for a machine tool having a rotation spindle (14) with a main axis of rotation (19). The chuck comprises a base plate (1), a first rotatable plate (2) eccentrically mounted on the base plate (1), a second rotatable plate (3) eccentrically mounted on the first rotatable plate (2), balancing means (6, 11) for aligning a principal axis of inertia of the chuck with the main axis of rotation (19) and a holding mechanism (17,18). The chuck is provided with an actuating mechanism for angularly displacing the first rotatable plate (2) around a first rotation axis (20) over a first angle of rotation and/or the second rotatable plate (3) around a second rotation axis (21) over a second angle of rotation such that the position of the object (13) with respect to the main axis of rotation (19) can be altered.