U-Cross-Section Bending Process to Prevent Wrinkling

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Solution Overview

Problem

Conventional UO-forming methods face challenges in producing bent tubes and irregular cross-section tubes due to issues like fracture, wrinkling, and creasing during the shaping process, leading to low yields and shaping defects.

Innovation Solution

The method involves separate steps for U-forming and longitudinal bending, using tooling with a die and punch where the bottom part of the die and punch extend straight in the longitudinal direction, and applying external forces to suppress creasing and wrinkling, allowing for stable bending and formation of U-cross-section bent articles without defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If U-forming and bending in the longitudinal direction are performed simultaneously, then the production process is simplified, but shaping defects such as fracture, wrinkling, and creasing occur

Engineering Contradiction:
Improveprocess complexityVSAvoidshaping quality
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the forming process into two separate steps: first U-forming to create a U-shaped article with a straight bottom part, then bending in the longitudinal direction to create the bent shape. This segmentation prevents the simultaneous application of forming and bending forces that cause defects, allowing each operation to be optimized independently for high quality results.

Inventive Principle:
Principle #1Segmentation

2Productivity

If bending in the longitudinal direction is performed at the time of U-forming, then the number of steps is reduced, but yields decrease due to shaping defects

Engineering Contradiction:
Improveproduction efficiencyVSAvoidproduction yield
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent performs U-forming first to create a stable U-shaped article with a straight bottom part before proceeding to bending. This preliminary action ensures the material is properly prepared and positioned, reducing the risk of defects during the subsequent bending operation and thereby improving overall production yield.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If conventional UO-forming is used, then straight shaped tubes can be produced, but bent tubes and irregular cross-section tubes cannot be formed

Engineering Contradiction:
Improveproduct shape rangeVSAvoidforming difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent introduces a dynamic bending process that can accommodate various bending radii and angles after the initial U-forming. This dynamic approach allows the same basic process to produce straight tubes, bent tubes, and irregular cross-section tubes by adjusting bending parameters, significantly expanding product versatility while maintaining manufacturing simplicity.

Inventive Principle:
Principle #15Dynamics

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

This approach effectively suppresses shaping defects in U-cross-section bent articles and enables the production of tubular shaped articles with improved yield and reduced wrinkling and fracture rates, allowing for more complex shapes and larger shaping ranges.

Implementation Method 1

press-forming a metal plate into a U-shape to obtain a U-shaped article having a bottom part straight extending in a longitudinal direction

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

applying external forces to suppress creasing and wrinkling, allowing for stable bending

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP3195951B1Method for manufacturing molded article and mold
Publication Date: 2023.07.12 NIPPON STEEL CORPORATION
  • EP3195951B1 patent drawingFigure 1A~1F
  • EP3195951B1 patent drawingFigure 2A~3
  • EP3195951B1 patent drawingFigure 4A~5D

AI summary

A method of production of a shaped article able to suppress occurrence of shaping defects, that is, a method of production of a shaped article including a first step of press-forming a metal plate (1a) into a U-shape to obtain a U-shaped article (1b) having a bottom part (2) straight extending in a longitudinal direction and a second step of press-forming the U-shaped article (1b) to bend it in the longitudinal direction so that the bottom part (2) of the part projects to the inside and obtain a U-cross-section bent article (1c).