Vehicle Frame Sheet Metal Shaping for Laser-Softening Tolerance Control

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Solution Overview

Problem

The laser-softening process for vehicle frame parts induces geometrical distortions, leading to parts being out of tolerance, which complicates validation and increases costs due to the need for additional post-processing steps.

Innovation Solution

A three-dimensional distortion-absorbing area is created within the sheet metal part to enclose the locally heat-softened portion, absorbing dimensional distortions and maintaining part stability within predetermined tolerances, using a dedicated recess or projection with specific dimensions and shapes to counteract heat-induced tensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If laser softening is applied to reduce tensile strength in specific areas, then crash energy absorption is improved, but geometrical distortions occur causing parts to go out of tolerances

Engineering Contradiction:
Improvetensile strengthVSAvoidgeometrical tolerances
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

A distortion-compensating geometric feature is integrated into the part design before the laser softening process. This feature is预先 designed to counteract the expected thermal distortions, allowing the part to maintain tolerances after heat treatment without requiring additional post-processing steps

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the geometric parameters of specific areas by introducing a distortion-absorbing feature with specific dimensions and shape. This feature is designed to absorb dimensional changes during laser softening, maintaining the overall part geometry within tolerances while allowing local tensile strength reduction

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If post-processing steps are added to correct geometrical distortions, then manufacturing precision is improved, but production costs and complexity increase

Engineering Contradiction:
Improvegeometrical tolerancesVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The distortion-compensating feature is designed and integrated into the part during the initial forming process, before laser softening occurs. This preliminary design approach eliminates the need for additional post-processing steps to correct distortions, simplifying the overall production process while maintaining precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The distortion-absorbing feature acts as a self-compensating mechanism that automatically counteracts thermal distortions during laser softening. The part's own geometry serves to correct itself, eliminating the need for external post-processing operations and reducing production complexity

Inventive Principle:
Principle #25Self-service

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 reduces deformations by up to 93.9% and maintains part tolerances, ensuring enhanced crash behavior and production quality without additional processing costs.

Implementation Method 1

The laser softening process... consists of a non-isothermal rapid heating treatment of hot stamping parts

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

This results in a tempering of the martensite contained in the material and thus a reduction of the tensile strength

Methodology Applied
Scientific EffectTempering: Heat Treatment

Implementation Method 3

it induces geometrical distortions in the parts... absorb the dimensional distortions induced by said locally heat-softened first portion

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4054777B1A forming sheet metal part for a vehicle frame and corresponding production method
Publication Date: 2023.09.13 AUTOTECH ENG SL
  • EP4054777B1 patent drawingFigure 1~3
  • EP4054777B1 patent drawingFigure 4A~4B
  • EP4054777B1 patent drawingFigure 5~7

AI summary

The invention relates to a forming sheet metal part (1) for a vehicle frame comprising: a first portion (2) being locally heat-softened after the sheet metal part (1) has been formed out. The part (1) further comprises a dedicated three-dimensional distortion-absorbing area (4), defining an internal boundary (6) within which the first portion (2) is to be locally heat-softened after the sheet metal part (1) has been formed out. The distortion-absorbing area (4) is dimensioned such that once said locally heat-softening step has been performed, the internal boundary (6) is adjacent to the first portion (2) and encloses the first portion (2) to absorb the dimensional distortions induced by the locally heat- softened first portion. The invention further relates to a method for producing a forming sheet metal part (1).