Hot-Formed Vehicle Components With Integrated Edge Trimming

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Solution Overview

Problem

Hot forming processes for motor vehicle components result in hardened materials that are difficult to rework, especially for edge trimming, leading to high costs and abrasive wear, particularly when dealing with Tailor Welded Blanks with varying wall thicknesses, where subsequent trimming is often necessary to correct weld seam issues.

Innovation Solution

A method combining hot forming and hot cutting in a single press stroke, where edge trimming is performed vertically and completed before the forming process begins, using a cutting tool driven exclusively by the press stroke, eliminating the need for subsequent trimming and reducing tool wear, allowing for precise production of components with complex geometries like C-shaped or hat-shaped designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If edge trimming is performed after hot forming on hardened material, then component precision can be improved, but tool wear increases significantly and manufacturing cost rises

Engineering Contradiction:
Improvecomponent precisionVSAvoidmanufacturing effort
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent performs edge trimming before hot forming while the blank is still in a soft, unhardened state. This preliminary action allows the trimming to be completed with minimal tool wear and manufacturing effort, while the subsequent hot forming process maintains the precision of the trimmed edges through the forming operation itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the material parameter (hardness) by performing trimming before the hot forming process hardens the steel. By utilizing the soft state of the blank during trimming, the process avoids the difficulties of cutting hardened material, reducing tool wear and manufacturing complexity while maintaining precision.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If laser cutting is used for trimming hardened components, then precision can be improved, but manufacturing cost increases significantly

Engineering Contradiction:
Improvecomponent precisionVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent performs the cutting action before hot forming while the material is still soft and inexpensive to process. This preliminary trimming eliminates the need for expensive laser cutting of hardened components later, achieving precision at a fraction of the cost.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses a simple, inexpensive mechanical cutting tool for trimming the soft blank before forming, rather than investing in expensive laser cutting equipment for hardened components. The cutting tool operates on soft material where simple mechanics suffice, avoiding the need for costly high-precision thermal cutting systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If cold cutting is used on hardened components, then manufacturing cost can be reduced, but the risk of microcracking increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidcomponent reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the material parameter from hardened to soft state by performing cutting before hot forming. This allows inexpensive cold cutting methods to be used without the risk of microcracking, since the material is ductile and soft during the trimming operation.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If re-trimming is performed on tailor-welded blanks after welding, then weld seam precision can be improved, but manufacturing time and complexity increase

Engineering Contradiction:
Improveweld seam precisionVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs edge trimming on the tailor-welded blank before hot forming, while the material is still soft and formable. This preliminary trimming corrects any weld seam protrusions or offsets, and the subsequent hot forming process consolidates the weld area, eliminating the need for re-trimming and reducing total manufacturing time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent combines the trimming operation with the hot forming process by performing trimming on the blank before forming, rather than as a separate post-forming operation. This integration allows weld seam corrections to be made when the material is most formable, and the forming process itself helps finalize the precision of the trimmed edges.

Inventive Principle:
Principle #5Merging (Combining)

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 method enables cost-effective and precise production of motor vehicle components with high tolerance requirements, eliminating the need for additional trimming and reducing tool wear, while maintaining the material's structural integrity and precision, especially for components with different wall thicknesses.

Implementation Method 1

a sheet metal blank made of a hardenable steel alloy is heated to a temperature above the Ac1 or Ac3 point

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

The forming tool is then closed in a direct hot forming process and quickly cooled, so that the formed blank is hardened

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP4321271B1Method of manufacturing a motor vehicle component by hot forming with integrated trimming
Publication Date: 2024.07.31 BENTELER AUTOMOBILTECHNIK GMBH
  • EP4321271B1 patent drawingFigure 1a
  • EP4321271B1 patent drawingFigure 1b
  • EP4321271B1 patent drawingFigure 1c

AI summary

The present invention relates to a method for manufacturing a motor vehicle component (13) by hot forming and hot cutting, and in particular press hardening: • Providing a blank (6) made of a steel sheet alloy, in particular hardenable, • Heating it completely to a temperature greater than Ac1, in particular greater than Ac3, • Inserting it into a combined forming and cutting tool, • Fixing the inserted blank (6) in the forming and cutting tool by a punch arranged inside the tool, • At least partial circumferential edge trimming (10) before the start of forming or during a period of up to 50% of the forming progress and/or at least 20%, preferably more than 30% of the press stroke before bottom dead center, • Hot forming in one press stroke with the edge trimming (10) and optional press hardening.