Active Piezoelectric Tool for Machining Vibration Compensation

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Solution Overview

Problem

Machining vibrations, particularly in slender tools, lead to reduced performance and quality in turning and boring operations, resulting in higher costs and scrap rates due to chattering on finish surfaces.

Innovation Solution

An active machining tool equipped with a piezoelectric device that includes two facing supports, accelerometers, and piezoelectric actuators, which generate signals to compensate for torque and vibrations by elongating or retracting under a driving signal proportional to the tool's velocity, thereby mitigating harmful effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If slender tools are used for deep boring operations, then access to internal components is improved, but machining vibrations and chattering increase significantly

Engineering Contradiction:

Improveaccess to internal componentsVSAvoidmachining vibrations and chattering

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The system employs accelerometers to detect vibrations and a control unit that processes this information to generate compensating signals for the piezoelectric actuators, creating a closed-loop feedback system that actively counteracts harmful vibrations in real-time

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces traditional passive mechanical vibration damping methods with an active piezoelectric-based system that uses electrical signals and piezoelectric material deformation to counteract vibrations, enabling more precise and adaptive control

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If traditional vibration damping methods are used, then some vibration reduction is achieved, but the system complexity and cost increase without sufficient effectiveness

Engineering Contradiction:

Improvevibration reductionVSAvoidsystem complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The piezoelectric actuators serve multiple functions: they can counteract vibrations in multiple directions, compensate for torque, and adapt to different machining conditions, reducing the need for separate dedicated components for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically changes the electrical parameters (voltage, frequency) applied to the piezoelectric actuators based on real-time vibration measurements, allowing adaptive optimization of vibration compensation without fixed mechanical adjustments

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If active vibration compensation systems are implemented, then machining quality improves, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improvemachining quality and surface finishVSAvoiddevice complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The piezoelectric actuators are integrated within the existing toolbar structure, with components nested within each other (accelerometers embedded in the toolbar, actuators positioned within the toolbar cross-section), minimizing additional space and complexity

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The system combines the vibration sensing, signal processing, and actuation functions into an integrated control system that operates as a unified unit, reducing the number of separate components and interfaces

Inventive Principle:

Principle #5Merging (Combining)

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 solution effectively reduces vibrations and torque, improving machining quality and reducing costs by up to 80% in material removal rate and surface quality, with no need for frequency response measurements.

Implementation Method 1

The piezoelectric device also comprises piezoelectric actuators arranged between the two supports, capable of elongating or retracting under a driving signal

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

one or preferably two accelerometers, configured to generate an electric signal proportional to the velocity of the toolbar

Methodology Applied

Scientific EffectAccelerometer detection: Accelerometer

Data Source

PatentUS20240024965A1Active piezoelectric tool, active piezoelectric device and operating method of the active piezoelectric tool

Publication Date: 2024.01.25 NUOVO PIGNONE TECH SRL

AI summary

A toolbar with a longitudinal axis and a machining tool for machining a workpiece, the toolbar comprising at least one accelerometer configured to generate an electric signal proportional to the velocity of the toolbar along a direction; at least one piezoelectric actuator; and a control logic unit, operatively connected to the at least one accelerometer and to the at least one piezoelectric actuator, wherein control logic unit is configured to drive the at least one piezoelectric actuator by a driving signal proportional to the velocity derived from at least one accelerometer adapted to compensate the torque and the vibrations on the toolbar.