Surface Roughness Prediction Using Frequency-Spectrum Coefficients

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Solution Overview

Problem

Existing methods struggle to accurately predict the surface roughness of workpieces machined by machine tools due to factors unrelated to the machine tool's performance, such as tool wear and operator setup, making it difficult to reliably forecast the surface roughness of actual products based solely on test piece measurements.

Innovation Solution

A computation device and method that acquire measurement data and physical quantities related to machine tool performance, perform frequency analysis, and calculate a coefficient to equate amplitude values at specific frequencies, enabling prediction of surface roughness by converting physical quantities into amplitude spectra and multiplying them with the coefficient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If surface roughness is measured by experimentally machining a test piece, then measurement data can be obtained, but the measurement is greatly affected by factors unrelated to machine tool performance such as tool wear and operator setup

Engineering Contradiction:
Improvesurface roughness measurement accuracyVSAvoidprediction reliability for actual workpieces
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent segments the surface roughness measurement into two independent components: (1) measurement data from test piece machining that captures all factors including operator setup and tool wear, and (2) physical quantity data from machine tool performance monitoring. By separating these components and using frequency analysis to identify machine tool-specific characteristics, the system isolates the reliable machine tool performance indicators from the variable operational factors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary computational model that uses frequency analysis and amplitude spectrum comparison to bridge the gap between test piece measurements and actual workpiece predictions. The model acts as a mediator that processes both measurement data and physical quantity data, using coefficient calculation to establish a reliable prediction relationship that filters out unrelated factors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If only test piece measurement data is used, then the process is simple, but it is difficult to accurately predict the surface roughness of actual workpieces

Engineering Contradiction:
Improvemeasurement process simplicityVSAvoidsurface roughness prediction accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent merges two data sources: simple test piece surface roughness measurement data and machine tool physical quantity data. By combining these datasets and performing joint frequency analysis, the system maintains the simplicity of test piece measurement while adding machine tool performance indicators to improve prediction accuracy for actual workpieces.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal prediction model that can handle both test piece measurements and machine tool performance data. The computational device performs multiple functions: it processes surface roughness data, processes physical quantity data, performs frequency analysis on both, and generates predictions that are universally applicable to actual workpieces regardless of variations in test piece machining conditions.

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

3Measurement precision

If frequency analysis and coefficient calculation are performed to predict surface roughness, then prediction accuracy improves, but the computational complexity increases

Engineering Contradiction:
Improvesurface roughness prediction accuracyVSAvoidcomputation device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies partial action by performing frequency analysis selectively on specific components of the measurement and physical quantity data. Rather than processing all frequency components equally, the system identifies and focuses on the relevant frequency ranges that correspond to machine tool performance characteristics, reducing unnecessary computational complexity while maintaining prediction accuracy.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS20230258447A1Calculation device, surface roughness prediction system, and calculation method
Publication Date: 2023.08.17 FANUC LTD
  • US20230258447A1 patent drawing
  • US20230258447A1 patent drawing
  • US20230258447A1 patent drawing

AI summary

This calculation device for predicting the surface roughness of a processed product from a physical quantity includes: a measurement data acquisition unit which acquires measurement data of surface roughness measured by a surface roughness measuring device; a physical quantity acquisition unit which acquires a physical quantity indicating a factor that causes surface roughness; a first amplitude spectrum conversion unit which converts the measurement data into a first amplitude spectrum; a second amplitude spectrum conversion unit which converts the physical quantity into a second amplitude spectrum; and a coefficient calculation unit which calculates a coefficient on the basis of a specific frequency, the second amplitude spectrum, and the first amplitude spectrum.