Burnishing Surface Quality Prediction Using Vibration Signals

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Solution Overview

Problem

Current ultrasonic burnishing processes face inefficiencies in monitoring surface quality during machining due to complex nonlinear dynamics and inherent defects in metallic materials, leading to potential fatigue failure and prolonged testing cycles.

Innovation Solution

A method involving vibration signal measurement and acquisition, ensemble empirical mode decomposition, and a support vector machine with Bayesian optimization to predict surface quality in real-time by analyzing time-frequency domain characteristics and optimizing kernel function parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional post-processing measurement methods are used (electron microscopes, X-ray diffractometers, etc.), then measurement precision of surface quality is improved, but productivity is reduced due to prolonged testing cycles and multiple processing steps

Engineering Contradiction:
Improvesurface quality measurement precisionVSAvoidtesting efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent replaces complex mechanical measurement systems (electron microscopes, X-ray diffractometers requiring multiple processing steps) with an acoustic emission-based detection system that uses sensors to directly capture surface quality information during machining, eliminating the need for post-processing measurement steps

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements real-time surface quality detection during the burnishing process itself, allowing for immediate feedback and parameter adjustment before the machining is complete, rather than waiting for post-processing measurement after the workpiece has been fully manufactured

Inventive Principle:
Principle #10Preliminary action

2Reliability

If process parameters are not optimized in real-time, then device complexity is reduced, but reliability deteriorates due to chaotic characteristics and sensitivity to initial conditions in the nonlinear dynamical system

Engineering Contradiction:
Improvesurface quality stabilityVSAvoidmonitoring and control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a closed-loop feedback system where acoustic emission sensors continuously monitor the burnishing process, the data is analyzed in real-time, and process parameters are automatically adjusted based on the detected surface quality trends, creating a self-regulating system that maintains stability despite the nonlinear chaotic nature of the process

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses the acoustic emission signals generated naturally during the burnishing process itself as the monitoring source, eliminating the need for external complex measurement equipment, and the system automatically adjusts its own parameters based on real-time analysis of these signals

Inventive Principle:
Principle #25Self-service

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 rapid and accurate classification of surface quality, improving testing efficiency and allowing for timely optimization of process parameters to prevent defects, with an accuracy of 88.9% as demonstrated by the support vector machine model.

Implementation Method 1

determining main influencing factors affecting surface quality of a burnishing workpiece and the number of each influencing factor, designing orthogonal tests with different combinations of influencing factors and levels, performing burnishing tests and acquiring vibration signals

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

dividing vibration signals in different scales by using the ensemble empirical mode decomposition method to achieve noise reduction

Methodology Applied
Scientific EffectSignal decomposition:

Implementation Method 3

calculating the time-frequency domain characteristics of superposed signals; selecting a support vector machine as a decision-making model of the workpiece surface quality, selecting a radial basis function as a kernel function

Methodology Applied
Scientific EffectTime-frequency analysis:

Implementation Method 4

Ultrasonic burnishing processing is a machining technology which utilizes ultrasonic waves to perform high-frequency impact on a workpiece based on the traditional burnishing technology

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Implementation Method 5

After ultrasonic burnishing process, grains on the surface layer of the workpiece are refined and a gradient nano-layered structure is formed

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS11879869B2Method for predicting surface quality of burnishing workpiece
Publication Date: 2024.01.23 ZHEJIANG UNIV OF TECH
  • US11879869B2 patent drawing
  • US11879869B2 patent drawing
  • US11879869B2 patent drawing

AI summary

Disclosed is a method for predicting surface quality of a burnishing workpiece. The method includes the steps: using vibration sensors and signal acquisition instrument to acquire vibration signals generated on a surface of the burnishing workpiece during machining, evaluating the surface quality of the burnishing workpiece based on a coupling coordination degree model, processing signals by using an ensemble empirical mode decomposition method, identifying power spectral density, kurtosis and form factor as signal characteristics, identifying a support vector machine as a decision-making model, optimizing penalty parameters and kernel function parameters by using the Bayesian optimization method, and establishing the relationship between the signal characteristics and the surface quality. The method can quickly identify the signal characteristics for evaluating the workpiece surface quality, thereby improving the workpiece surface quality by intervening in process parameters, making up for the technical defect that condition monitoring cannot be performed during the machining process.