Superplastic Forming Coating Thickness for Wrinkle Control

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Solution Overview

Problem

Conventional methods for mitigating wrinkles in super-plastically formed parts are inefficient and costly, as they require complex die modifications that are difficult to implement and often result in unsuitable parts due to wrinkles.

Innovation Solution

A method involving the application of a friction-modifying layer with non-uniform thicknesses to specific portions of the part assembly, combined with controlled stress management through flanges and surface irregularities, to ensure a uniform stress state during super-plastic formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hard features are incorporated into the die geometry to mitigate wrinkles, then wrinkle mitigation is improved, but device complexity and manufacturing cost increase substantially

Engineering Contradiction:
Improvewrinkle mitigationVSAvoiddie complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

A friction-modifying layer is introduced as an intermediary between the die and the part assembly. This layer, applied to the die surface at wrinkle-prone locations, controls friction to prevent wrinkle formation without requiring complex die geometry modifications. The layer acts as a mediator that simplifies the die design while achieving the same wrinkle mitigation effect.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The friction-modifying layer is applied selectively only to specific regions of the die where wrinkles are predicted to form, rather than modifying the entire die geometry. This localized approach reduces device complexity and manufacturing cost while maintaining effective wrinkle mitigation at critical locations.

Inventive Principle:
Principle #3Local quality

2Reliability

If hard features are incorporated into the die geometry to mitigate wrinkles, then wrinkle mitigation is improved, but ease of manufacture deteriorates due to difficult implementation and multiple adjustments

Engineering Contradiction:
Improvewrinkle mitigationVSAvoiddie manufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The friction-modifying layer serves as a removable intermediary that simplifies manufacturing. Instead of permanently modifying die geometry through complex machining or additive processes, the layer can be applied and removed easily, making the manufacturing process simpler and more adaptable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the friction parameter at the die-part interface by applying a friction-modifying layer, rather than changing the geometric parameters of the die. This parameter change approach is easier to implement and adjust during manufacturing compared to modifying die geometry.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional die modifications are used to mitigate wrinkles, then wrinkle mitigation is improved, but loss of time increases due to multiple adjustments required

Engineering Contradiction:
Improvewrinkle mitigationVSAvoidmanufacturing cycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Wrinkle-prone locations are identified through simulation before the actual forming process, and friction-modifying layers are pre-applied to these locations. This preliminary action eliminates the need for multiple trial-and-error adjustments during production, reducing manufacturing cycle time while maintaining effective wrinkle mitigation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Simulation results provide feedback on wrinkle-prone locations, which guides the selective application of friction-modifying layers. This feedback loop enables precise targeting of treatment areas, reducing the need for broad, time-consuming die modifications and multiple adjustments.

Inventive Principle:
Principle #23Feedback

4Manufacturing precision

If friction-modifying layer with non-uniform thickness is applied to control stress, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvestress uniformityVSAvoidapplication process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The friction-modifying layer is applied with non-uniform thickness specifically at wrinkle-prone locations rather than uniformly across the entire die surface. This localized variation in layer thickness provides precise stress control where needed without complicating the overall application process excessively.

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 reduces or eliminates wrinkles, producing wrinkle-mitigated parts by managing stress uniformly across the assembly, thereby enhancing the manufacturing process efficiency and quality.

Implementation Method 1

applying a friction-modifying layer to the first outer sheet of the part assembly... controlling a state of stress within the part assembly during the super-plastic forming process

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

super-plastically forming the part assembly into the formed part... moving an upper die of the die system in a forming direction toward the lower die to stretch and compress the part assembly

Methodology Applied
Scientific EffectSuperplasticity: Superplasticity

Data Source

PatentEP4596133A1Method of mitigating wrinkles during the manufacture of super-plastically formed parts
Publication Date: 2025.08.06 THE BOEING CO
  • EP4596133A1 patent drawingFigure 1
  • EP4596133A1 patent drawingFigure 2A~2B
  • EP4596133A1 patent drawingFigure 3

AI summary

A method (200) of mitigating wrinkles during a manufacture of a super-plastically formed part, the method (200) comprising: arranging (202) a plurality of flat sheets (104) into a part assembly (106), the plurality of flat sheets (104) comprising a first outer sheet (108) and a second outer sheet (110); applying (204) a friction-modifying layer (120) to the first outer sheet (108) of the part assembly (106), wherein: the first outer sheet (108) comprises a first portion (116) having a first percentage of coverage and a second portion (118) having a second percentage of coverage; the friction-modifying layer (120) is applied at a first thickness (122) in the first portion (116) and a second thickness (124) in the second portion (118); and the first thickness (122) and the second thickness (124) are different thicknesses; placing (206) the part assembly (106) on a lower die (134) of a die system (130) such that the first outer sheet (108) is facing the lower die (134); and moving an upper die (132) of the die system (130) in a forming direction (136) toward the lower die (134) to stretch and compress the part assembly (106) between the upper die (132) and the lower die (134) and to super-plastically form the part assembly (106) into a formed part (102).