Thrust Reverser Cascade Array Overmolding Segmentation

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Solution Overview

Problem

The manufacture of thrust reverser cascade arrays for aircraft propulsion systems is time-consuming and labor-intensive due to their complex three-dimensional configuration, making current methods expensive and inefficient.

Innovation Solution

The use of comb subassemblies formed through an overmolding process, where strongbacks are coupled with vanes and fillets to create a unitary structure, allowing for the formation of complex geometries that are less expensive to produce and assemble, using thermoplastic materials and ultrasonic welding for attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If hand layup of individual vanes between adjacent strongbacks is used, then the cascade array can be manufactured with complex three-dimensional configuration, but the manufacturing process becomes time-consuming and labor-intensive

Engineering Contradiction:

Improvecomplex three-dimensional configurationVSAvoidmanufacturing time and labor

Core Design Contradiction:

ShapeVSProductivity

Solution Approach 1:

The cascade array is divided into multiple comb subassemblies, each comprising a strongback with attached vanes. These subassemblies are manufactured separately through injection molding and then assembled together using friction stir welding to form the complete cascade array. This segmentation enables parallel manufacturing of multiple subassemblies, significantly improving productivity while maintaining the complex three-dimensional configuration of each subassembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The vanes are pre-attached to the strongbacks to form complete comb subassemblies through injection molding before the final assembly of the cascade array. This preliminary action of creating pre-assembled units allows for more efficient manufacturing and assembly processes, reducing the overall manufacturing time and labor requirements compared to assembling individual vanes.

Inventive Principle:

Principle #10Preliminary action

2Shape

If hand layup and curing process is used for manufacturing cascade arrays, then the complex geometry can be achieved, but the manufacturing cost increases due to time-intensive manual processes

Engineering Contradiction:

Improvecomplex geometryVSAvoidmanufacturing cost

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The manual hand layup and curing process is replaced with injection molding technology for manufacturing the comb subassemblies. This mechanical substitution automates the manufacturing process, eliminates labor-intensive manual operations, and significantly reduces manufacturing time and cost while maintaining the ability to produce complex geometries through mold design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The manufacturing approach transitions from batch manual processing to high-volume injection molding production. This parameter change in the manufacturing process enables economies of scale, reducing the cost per unit while maintaining the complex geometric requirements through precise mold engineering.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If multiple separate components are assembled manually, then the cascade array can be constructed, but the assembly process becomes labor-intensive and expensive

Engineering Contradiction:

Improveassembly structureVSAvoidassembly labor

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The cascade array is segmented into comb subassemblies that are pre-assembled through injection molding with integrated vanes and strongbacks. These pre-formed subassemblies are then quickly joined using friction stir welding, which automates the assembly process and significantly reduces labor requirements compared to manual assembly of individual components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Manual assembly operations are replaced with automated friction stir welding technology for joining the comb subassemblies. This mechanical substitution provides consistent, repeatable assembly processes with higher productivity and lower labor costs while maintaining the structural integrity and complexity of the overall assembly.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 the efficient and cost-effective production of cascade arrays with complex geometries, reducing manufacturing time and labor while maintaining mechanical strength and functionality.

Implementation Method 1

formed through an overmolding process

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

using thermoplastic materials and ultrasonic welding for attachment

Methodology Applied

Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP3974641B1Thrust reverser cascade array and method for producing the same

Publication Date: 2024.05.08 ROHR INC

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AI summary

A method of producing a cascade array (124) and a cascade array (124) is provided. The method includes: forming a plurality of strongbacks (130) from a first thermoplastic material; forming a plurality of comb subassemblies (170), each said comb subassembly (170) including one of the plurality of strongbacks (130) and a plurality of vanes (132) comprising a second thermoplastic material extending outwardly from the respective one of the plurality strongbacks (130); and attaching the plurality of comb subassemblies (170) into a unitary structure to produce the cascade array (124).