Piezoelectric Tool Tip for Dual-Speed Microstructure Machining

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Solution Overview

Problem

Conventional methods for creating microreplicated structures, such as chemical etching and bead blasting, are incapable of producing highly accurate and repeating sharp features, which are essential for achieving desired light diffusion characteristics.

Innovation Solution

A cutting tool assembly with a piezoelectric actuator and tool post system that allows for variable and independent movement in the x-direction and z-direction, enabling precise control of a tool tip for machining microstructures, utilizing a PZT stack and dual in-line actuator for high precision and speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional methods such as chemical etching and bead blasting are used to create microstructures, then the process is simpler and more accessible, but the manufacturing precision and repeatability deteriorate due to inherent impreciseness and unrepeatability

Engineering Contradiction:
Improveprecision of microstructure featuresVSAvoidcomplexity of machining system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cutting tool system is segmented into multiple independent actuation mechanisms: a primary actuator for gross positioning and a fast tool servo (FTS) actuator for fine precision control. This segmentation allows each component to specialize in a specific function range, achieving high manufacturing precision without requiring the entire system to be overly complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system employs dynamic control through the FTS actuator that operates at high frequencies (up to 10 kHz) to dynamically adjust tool tip position during machining. This dynamic capability enables real-time compensation and precise control of cutting forces, achieving sub-optical wavelength precision in microstructure fabrication.

Inventive Principle:
Principle #15Dynamics

2Productivity

If a single-speed actuator is used for tool tip movement, then the device complexity is reduced, but the productivity deteriorates due to inability to selectively cut at different speeds

Engineering Contradiction:
Improvecutting speed variabilityVSAvoidactuator system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system merges two actuator systems with different speed characteristics into a single integrated tool positioning system. The primary actuator provides low-speed gross movement while the FTS actuator provides high-speed fine adjustment, combining their capabilities to achieve both粗加工 and精加工 functions through one unified system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dual-actuator system provides multi-functionality by enabling the tool tip to operate at multiple speed ranges depending on the machining requirements. The same tool positioning system can perform both slow precision cutting and fast material removal, making it universally applicable to various cutting operations.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If high precision machining is performed at slow speeds, then the manufacturing precision is improved, but the productivity decreases due to limited cutting speed

Engineering Contradiction:
Improveprecision of microstructure featuresVSAvoidcutting speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The FTS actuator enables dynamic speed adjustment during the machining process, allowing the system to switch between slow speeds for precision cutting and faster speeds for material removal. This dynamic capability resolves the trade-off by making cutting speed variable rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system applies preliminary high-frequency adjustments through the FTS actuator to counteract the limitations of slow cutting speeds. By pre-positioning the tool tip with high-speed adjustments, the system can achieve precision machining results without being constrained by slow primary actuator speeds.

Inventive Principle:
Principle #9Preliminary anti-action

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

Enables the creation of microstructures with high precision and accuracy, capable of producing features with dimensions down to sub-optical wavelengths, overcoming the limitations of imprecise and non-repeating stochastic surface modification techniques.

Implementation Method 1

an actuator including a piezoelectric stack

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP1948391B1Cutting tool having variable movement at two simultaneously independent speeds in an x-direction into a work piece for making microstructures
Publication Date: 2019.04.03 3M INNOVATIVE PROPERTIES CO
  • EP1948391B1 patent drawingFigure 1
  • EP1948391B1 patent drawingFigure 2~3
  • EP1948391B1 patent drawingFigure 4A~5D

AI summary

A cutting tool assembly having a tool post capable of lateral movement along a work piece to be cut and an actuator with a tool tip. The actuator provides for variable control of the movement of the tool tip in an x-direction into the work piece at two simultaneously independent speeds for use in making microstructures in the work piece.