Adaptive Precision Chuck With Self-Centering Compliant Flexures
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Solution Overview
Problem
In precision and ultraprecision machining, existing chuck systems face challenges with misalignment between the workpiece and spindle rotational axis, leading to machining errors and defects, particularly in applications like contact lens production, due to complex and costly designs that require manual setup and are prone to misalignment during machining.
Innovation Solution
An adaptive precision chuck with integrated compliant flexures that self-center and clamp the workpiece using rotational forces, eliminating misalignment and reducing friction and tolerance issues, allowing for a single, robust, and cost-effective device with minimal setup requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual mounting and tuning by skilled operator is used, then alignment precision can be achieved, but setup time increases and operator skill requirement increases
Solution Approach 1:
The chuck system performs self-centering and self-alignment automatically through the interaction of compliant jaws with the workpiece and centrifugal forces during rotation, eliminating the need for manual mounting and tuning by skilled operators while maintaining high alignment precision
Solution Approach 2:
The system changes the state of the jaws from static to dynamically compliant during rotation, utilizing centrifugal force to activate the centering mechanism and achieve precise alignment automatically without manual intervention
2Reliability
If vacuum chuck or magnetic clamping system is used, then workpiece holding is achieved, but misalignment can arise during machining if machining force overcomes clamping force
Solution Approach 1:
The jaws are designed to be dynamically compliant rather than rigid, allowing them to adapt their position during machining operations. This dynamic compliance enables the jaws to maintain both secure holding and precise alignment even when machining forces vary, preventing misalignment that would occur with static clamping systems
Solution Approach 2:
The system utilizes changes in centrifugal force with rotation speed to activate and adjust the clamping and centering mechanism, allowing the jaws to provide appropriate holding force while maintaining alignment accuracy throughout the machining process
3Manufacturing precision
If workpiece specific holders that closely match the shape or other properties of the workpiece are used, then misalignment is minimized, but flexibility of the machining system reduces and costs increase
Solution Approach 1:
The chuck with compliant jaws is designed to accommodate multiple workpiece types and geometries through its adaptive centering mechanism. The jaws can conform to different workpiece shapes while automatically achieving precise alignment, providing universal applicability without requiring workpiece-specific holders, thus maintaining system flexibility while ensuring alignment accuracy
4Manufacturing precision
If complex centring and jaw mechanism is used, then alignment precision is improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The centering and clamping functions are merged into a single integrated mechanism where the compliant jaws perform both alignment and holding operations simultaneously. This unified approach achieves high alignment precision without requiring separate complex centring mechanisms, thereby reducing overall device complexity and manufacturing cost
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 adaptive chuck achieves sub-micron accuracy, efficient user-defined setup, reduced noise and lubrication needs, and secure workpiece holding across varying speeds, enhancing machining precision and reducing manufacturing overheads.
Implementation Method 1
a plurality of compliant flexures configured, upon application of rotational forces by the machining system to the chuck about the axis of rotation, to engage the jaws upon a workpiece in the mount
Implementation Method 2
upon application of rotational forces by the machining system to the chuck about the axis of rotation
Data Source
AI summary
An adaptive precision chuck for a precision/ultraprecision machining system is described. The chuck (200) defining a mount for receiving a workpiece (300) wherein, when in use, the centre of the mount is configured to be substantially concentric with an axis of rotation (214) of the machining system, the chuck (200) further including jaws (201) about the mount and a plurality of compliant flexures (203-206) configured, upon application of rotational forces by the machining system to the chuck about the axis of rotation (214), to engage the jaws (210) upon a workpiece (300) in the mount.