Press-Formed Hat Section Blank Geometry for Flange Crack Prevention

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Solution Overview

Problem

The free bending method for manufacturing L-shaped, T-shaped, and Y-shaped profile components often results in flange cracking and top plate edge cracking, especially when the width of the top plate section is long, due to excessive inflow of the blank during pressing, and existing techniques fail to provide effective solutions for preventing these issues.

Innovation Solution

The method involves providing an excess portion with a first recess, a protrusion, and a second recess to the edge of the flange section in the blank, which reduces the displacement from the top plate section to the vertical wall section, thereby suppressing flange cracking and top plate edge cracking by straightening out these features during pressing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the free bending method is used to manufacture L-shaped, T-shaped, and Y-shaped profile components, then manufacturing efficiency is improved, but flange cracking and top plate edge cracking occur due to excessive inflow of the blank during pressing

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidcracking prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming specific geometric features (first recess, protrusion, and second recess) on the blank before the pressing operation. These pre-formed features control the material flow during subsequent pressing, preventing excessive inflow that causes cracking while maintaining the efficiency of the free bending method. The excess portion with controlled geometry is prepared in advance to manage deformation uniformly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by creating non-uniform geometric features (recesses and protrusions) at specific locations on the blank. These localized geometric modifications create varying material resistance and flow characteristics in different regions, allowing controlled deformation in areas prone to cracking while maintaining overall forming efficiency. The first recess, protrusion, and second recess are strategically positioned to address local deformation issues.

Inventive Principle:
Principle #3Local quality

2Length of moving object

If the width of the top plate section is increased, then component functionality is improved, but flange cracking and top plate edge cracking occur due to excessive blank inflow

Engineering Contradiction:
Improvetop plate section widthVSAvoidcracking prevention
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming specific geometric features (first recess, protrusion, and second recess) on the blank before the pressing operation. These pre-formed features control the material flow during subsequent pressing, preventing excessive inflow that causes cracking while maintaining the efficiency of the free bending method. The excess portion with controlled geometry is prepared in advance to manage deformation uniformly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by creating non-uniform geometric features (recesses and protrusions) at specific locations on the blank. These localized geometric modifications create varying material resistance and flow characteristics in different regions, allowing controlled deformation in areas prone to cracking while maintaining overall forming efficiency. The first recess, protrusion, and second recess are strategically positioned to address local deformation issues.

Inventive Principle:
Principle #3Local quality

3Weight of moving object

If high-strength blanks are used to reduce weight, then weight reduction is achieved, but manufacturing difficulty increases due to susceptibility to cracking

Engineering Contradiction:
Improvecomponent weightVSAvoidmanufacturing difficulty
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-forming specific geometric features (first recess, protrusion, and second recess) on the blank before the pressing operation. These pre-formed features control the material flow during subsequent pressing, preventing excessive inflow that causes cracking while maintaining the efficiency of the free bending method. The excess portion with controlled geometry is prepared in advance to manage deformation uniformly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies local quality by creating non-uniform geometric features (recesses and protrusions) at specific locations on the blank. These localized geometric modifications create varying material resistance and flow characteristics in different regions, allowing controlled deformation in areas prone to cracking while maintaining overall forming efficiency. The first recess, protrusion, and second recess are strategically positioned to address local deformation issues.

Inventive Principle:
Principle #3Local quality

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 prevents creasing and cracking in the press-formed articles, allowing for the use of high-strength blanks without increasing weight or cost, and enables the production of components with longer top plate section widths without shape modifications.

Implementation Method 1

moving the die and the bending mold relative to each other in a pressing direction so as to form an L-shaped profile component by forming vertical wall sections and flange sections

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP2998043B1Method of manufacturing a worked component
Publication Date: 2022.09.14 NIPPON STEEL CORPORATION
  • EP2998043B1 patent drawingFigure 1
  • EP2998043B1 patent drawingFigure 2
  • EP2998043B1 patent drawingFigure 3

AI summary

A blank (30) that is a material for an elongated press formed article (20) having a substantially hat shaped lateral cross-section profile including a top plate section (20a), a ridge line section (20b), a flange section (20c), and vertical wall section (20d), and configured with a first portion (21) in which the top plate section has a substantially fixed width, and a second portion (22) including a curved portion (23) in which the top plate section (20a) exhibits an L-shape in plan view due to the vertical wall section (20c), the ridge line section (20b), and the flange section (20d) curving along with the width of the top plate section gradually increasing. The blank (30) has a shape of an opened-out shape of the press formed article (20), additionally with a first recess (33), a protrusion (34), and a second recess (35) provided to an edge of an excess portion (32) additionally provided at an edge of a location that will form the flange section (20d) configuring the curved portion (23).