Porous Acoustic Layer Laser Drilling for Faster Open Surface Control

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Solution Overview

Problem

Current methods for manufacturing porous layers for acoustic attenuation structures are time-consuming, whether through mechanical drilling or laser ablation, due to the large number of holes required, which increases production time and risks damage to the material.

Innovation Solution

A method involving the production of a solid layer with a structural frame embedded in a resin matrix, where through-holes are created using a laser beam parameterized to maintain temperatures within specific ranges to avoid material alteration, reducing the number of passes and production time, while maintaining an optimal open surface ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If mechanical drilling or laser ablation is used to produce a large number of through-holes in the porous layer, then the open surface ratio can be greater than 10%, but the production time becomes very long (several tens of drilling hours or up to ten laser passes)

Engineering Contradiction:

Improvenumber of through-holesVSAvoidproduction time

Core Design Contradiction:

Quantity of substanceVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the porous layer into zones with reinforcing strips and zones without reinforcing strips. The laser beam is parameterized to selectively remove material only in zones without reinforcing strips, creating through-holes efficiently without damaging the structural frame. This segmentation allows parallel processing and reduces the number of passes required.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the laser beam parameters (power, pulse duration, frequency) to maintain the temperature in the impact zones within a specific range that is greater than the sublimation temperature of the resin matrix but less than the alteration temperature of the structural frame fibers. This parameter optimization enables single-pass or few-pass hole creation without material damage.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the laser beam power is increased to reduce the number of passes, then the production time decreases, but the risk of damaging the porous layer by burning increases

Engineering Contradiction:

Improvenumber of laser passesVSAvoidmaterial burning damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes laser beam parameters including power, pulse duration, and frequency to achieve the correct temperature window for resin sublimation without structural frame damage. This allows high-power single-pass drilling without burning the material.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating different thermal zones: the impact zones reach temperatures above resin sublimation for efficient hole creation, while the zones with reinforcing strips remain below fiber alteration temperatures. This localized temperature control prevents damage while maintaining productivity.

Inventive Principle:

Principle #3Local quality

3Object-generated harmful factors

If the diameter of through-holes is reduced to minimize drag, then the aerodynamic performance improves, but the number of holes must be increased to maintain the open surface ratio

Engineering Contradiction:

Improveaerodynamic dragVSAvoidnumber of through-holes

Core Design Contradiction:

Object-generated harmful factorsVSQuantity of substance

Solution Approach 1:

The patent segments the porous layer into zones with and without reinforcing strips, allowing concentrated hole creation in specific areas. This enables using smaller hole diameters for drag reduction while maintaining the required open surface ratio through strategic zone selection rather than uniform hole distribution.

Inventive Principle:

Principle #1Segmentation

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 significantly reduces the time to manufacture porous layers with a controlled open surface ratio, optimizing acoustic treatment and minimizing impact on aerodynamic performance.

Implementation Method 1

for a temperature in the zones of impact of the laser beam to be maintained within a range of temperatures greater than a sublimation temperature of the resin of the matrix

Methodology Applied

Scientific EffectSublimation: Sublimation

Implementation Method 2

the laser beam is parameterized so that the temperature in the impact zones is maintained within a range of temperatures greater than a sublimation temperature of the resin of the matrix and less than a temperature of alteration of the fibers of the structural frame

Methodology Applied

Scientific EffectLaser heating: Laser

Data Source

PatentUS11638972B2Method for manufacturing a porous layer of an acoustic attenuation structure, porous layer of an acoustic attenuation structure thus obtained and acoustic attenuation structure comprising said porous layer

Publication Date: 2023.05.02 AIRBUS OPERATIONS (SAS)

AI summary

A method for manufacturing a porous layer of an acoustic attenuation structure, porous layer of an acoustic attenuation structure thus obtained and acoustic attenuation structure comprising the porous layer. A method for manufacturing a porous layer of an acoustic attenuation structure includes a first step of production of a solid layer including at least one structural frame embedded in a resin matrix and having first and second reinforcing strips arranged so as to delimit zones without reinforcing strips and a second step of production of through-holes in the zones without reinforcing strips of the solid layer using a laser beam.