Line Displacement Evaluation Using 4th Order Differential Coefficient

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Solution Overview

Problem

Current methods fail to quantitatively evaluate line displacement in press-formed articles during character line formation, leading to inconsistent product quality due to the inability to accurately measure curvature changes along the character line.

Innovation Solution

A method involving the acquisition of a cross section profile, calculation of the 4th order differential coefficient, and evaluation of line displacement using parameters such as peak value H and displacement width L, with optional inclusion of curve radius R, to determine the line displacement evaluation parameter S or SII.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If curvature distribution is used for evaluation, then surface characteristics can be assessed, but quantitative line displacement evaluation remains difficult

Engineering Contradiction:

Improveevaluation consistencyVSAvoidline displacement quantification

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The invention changes the evaluation parameter from general curvature distribution to specific cross-sectional shape parameters. By calculating the cross-sectional curvature and comparing it with the design cross-section, the method provides quantitative line displacement evaluation through specific measurable parameters rather than qualitative curvature distribution analysis.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If sensory evaluation by workers is used, then line displacement can be detected, but product quality variations occur and criteria are not clarified

Engineering Contradiction:

Improveline displacement detectionVSAvoidproduct quality consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The invention replaces the mechanical sensory evaluation system (human workers visually inspecting and judging line displacement) with an automated measurement and calculation system. The system objectively measures cross-sectional profiles, calculates curvatures, and compares them with design data, eliminating subjectivity and providing consistent, quantifiable evaluation criteria for line displacement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10508909B2Line displacement evaluation method, line displacement evaluation device, program, and recording medium

Publication Date: 2019.12.17 NIPPON STEEL CORPORATION

AI summary

Provided is a line displacement evaluation method of evaluating line displacement occurring in a press-formed article in press forming of forming a character line. This method includes acquiring a cross section profile of the press-formed article measured so as to traverse the character line formed in the press-formed article; calculating a 4th order differential coefficient of the acquired cross section profile; and evaluating the line displacement, on the basis of the calculated 4th order differential coefficient of the cross section profile.