L-Shaped Press Component Molding with Crease Suppression

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Solution Overview

Problem

Conventional methods for manufacturing press components with a hat-shaped cross-section and L-shaped curvature along the longitudinal direction face challenges in preventing creases and cracks, especially when using high-strength sheet steel with low extensibility, leading to reduced material yield and increased manufacturing costs.

Innovation Solution

A manufacturing method and device that molds the vertical wall and flange portion at the inside periphery of the curved portion by moving the bender towards the punch, while maintaining the top plate section clamped against the punch, and the outside periphery clamped against the die, reducing stretching and compression stress, thereby minimizing crease formation and crack development.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If drawing method is used to manufacture L-shaped press component, then creases can be suppressed, but material waste increases and manufacturing cost increases

Engineering Contradiction:
Improvecrease suppressionVSAvoidmaterial waste
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The manufacturing process is divided into two distinct stages: first forming the vertical wall portion, then forming the flange portion. This segmentation allows each stage to be optimized independently, reducing overall material waste while preventing creases through controlled forming sequences

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vertical wall portion is formed first as a preliminary step before forming the flange portion. This preliminary action creates a stable base structure that prevents material instability and crease formation during subsequent flange forming operations

Inventive Principle:
Principle #10Preliminary action

2Strength

If high strength sheet steel is used, then crash safety performance improves, but extensibility decreases leading to cracks and creases

Engineering Contradiction:
Improvecrash safety performanceVSAvoidextensibility
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The forming process is segmented into separate stages for vertical wall and flange portions, allowing high strength sheet steel to be formed without excessive stretching in a single operation, thus preventing cracks while maintaining strength

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The forming parameters are changed by controlling the sequence of operations and using intermediate states between forming stages, enabling the use of high strength materials with low extensibility by reducing the total strain accumulation

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If bending method is used for straight frame member, then manufacturing is simple, but L-shaped curved components generate creases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcrease generation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The single bending operation is segmented into two sequential forming stages: vertical wall formation followed by flange formation. This segmentation maintains manufacturing simplicity while eliminating creases by controlling material flow in each stage

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The forming process uses dynamic control of the press machine to apply different forming forces and velocities in each stage, adapting the manufacturing process to prevent creases while maintaining operational 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 enables the production of press components with excellent yield and reduced material waste, preventing creases and cracks in high-strength sheet steel, even with tensile strengths above 590 MPa, while maintaining structural integrity and reducing vehicle weight.

Implementation Method 1

the portion of the metal stock sheet for forming the top plate section is press and clamped against the punch by the pad

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

the portion of the metal stock sheet that will be further to the outside of the L shaped curve portion than the portion for forming the top plate section is pressed and clamped against the die by the blank holder

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

the vertical wall and the flange portion at the inside periphery of the curved portion are molded by moving the bender in the direction toward where the punch is positioned

Methodology Applied
Scientific EffectPlasticity: Plasticity

Implementation Method 4

the vertical wall and the flange portion at the outside periphery of the curved portion are molded by moving the die and the blank holder relative to the metal stock sheet

Methodology Applied
Scientific EffectPlasticity: Plasticity

Data Source

PatentEP2942123B1Method and device for manufacturing a l-shaped component
Publication Date: 2019.02.06 NIPPON STEEL CORPORATION
  • EP2942123B1 patent drawingFigure 1(a)~1(e)
  • EP2942123B1 patent drawingFigure 2(a)~2(e)
  • EP2942123B1 patent drawingFigure 3(a)~3(b)

AI summary

The invention provides technology for manufacturing a press component that has a hat shaped cross-section and that is curved in an L shape along the longitudinal direction using sheet metal having a tensile strength of from 500 MPa to 1800 MPa as stock, without generating creases or cracks, and achieving high yield. The top plate section of the metal stock is pressed and clamped against a punch 72 by a pad 74, a portion that will be at the outside of the L shaped curve is pressed and camped against a die 71 by a blank holder 73, a bender 75 is moved, and a vertical wall portion at the inside of the L shaped curved of the metal stock sheet and the flange portion joined to the vertical wall at the inside of the L shaped curve are molded. The metal stock sheet is moved in the direction toward where the blank holder 73 is positioned while maintaining a state in which the metal stock sheet is pressed and clamped against the die 71 by the blank holder 73, and a vertical wall portion at the outside of the L shaped curve of the L shaped hat shaped cross-section and the flange portion joined to the vertical wall at the outside of the L shaped curve are molded.