Laser Aperture Formation in Fiber-Reinforced Composites

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Solution Overview

Problem

Forming through-holes in fiber-reinforced composite materials, such as those used in aircraft propulsion systems, is time-consuming and expensive, and existing methods like mechanical drilling can cause delamination due to heat generated by rapid laser drilling.

Innovation Solution

A process using a pulsed fiber laser with a scanner head that changes focal length and moves along spiral or circular trajectories to form apertures in fiber-reinforced composite objects, reducing delamination by allowing material cooling between laser pulses and maintaining the laser beam's energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If rapid laser drilling is used to form through-holes in fiber-reinforced composite material, then manufacturing time is reduced, but delamination occurs due to heat generation

Engineering Contradiction:
Improvemanufacturing timeVSAvoidstructural integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The laser beam is applied in periodic pulses rather than continuous operation, allowing intervals for heat dissipation and material cooling between pulses. This prevents excessive heat accumulation that causes delamination while maintaining efficient through-hole formation in fiber-reinforced composite materials.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The process begins with forming a pilot hole using a mechanical drill or laser, which creates a preliminary pathway through the composite material. This preliminary action reduces the subsequent laser drilling time and heat exposure required to complete the through-hole, preventing delamination while maintaining productivity.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If mechanical drilling is used to form through-holes in fiber-reinforced composite material, then delamination is avoided, but manufacturing time increases and cost increases

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

A mechanical drill or laser creates a pilot hole first, establishing a preliminary pathway through the composite material. This reduces the subsequent laser drilling time and heat exposure, combining the structural integrity benefits of mechanical drilling with the speed advantages of laser completion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The process replaces continuous mechanical drilling with a hybrid approach where a mechanical pilot hole is followed by laser completion. This substitution leverages the precision and speed of laser technology for the final through-hole formation while using mechanical drilling only for the initial pathway creation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If continuous laser beam is used to form apertures, then manufacturing speed increases, but heat accumulation causes delamination

Engineering Contradiction:
Improvemanufacturing speedVSAvoidheat accumulation
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The continuous laser beam is replaced with periodic pulsed laser application. The laser operates in cycles of activation and deactivation, creating intervals for heat dissipation between pulses. This maintains manufacturing speed while preventing excessive heat accumulation that leads to delamination in fiber-reinforced composite materials.

Inventive Principle:
Principle #19Periodic action

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 efficiently forms apertures in fiber-reinforced composite materials without delamination, reducing manufacturing time and cost while maintaining the structural integrity of the composite materials.

Implementation Method 1

forming apertures in a fiber-reinforced composite object with a laser

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The laser may be configured as or otherwise include a pulsed fiber laser

Methodology Applied
Scientific EffectPulsed laser heating: Laser

Data Source

PatentEP2915620B1Forming one or more apertures in a fiber-reinforced composite object with a laser
Publication Date: 2019.09.18 ROHR INC
  • EP2915620B1 patent drawingFigure 1
  • EP2915620B1 patent drawingFigure 2
  • EP2915620B1 patent drawingFigure 3

AI summary

A process is provided for forming a plurality of apertures (22) in a fiber-reinforced composite object (24) using a laser (30). The apertures (22) include at least a first aperture and a second aperture. During the process, a scanner head (38) of the laser (30) is operated from a location to selectively scan a laser beam over the object (24) to form a first portion of the first aperture and to form a first portion of the second aperture. The scanner head (38) is also operated from the location to selectively scan the laser beam over the object (24) to form a second portion of the first aperture and to form a second portion of the second aperture.