Laser Machining Backwall Protection via Fluid Absorption

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Solution Overview

Problem

Laser machining often results in damage to the backwall or opposite surface of a workpiece due to uncontrolled laser energy, leading to unwanted holes or structural degradation during the drilling process.

Innovation Solution

A protection system is implemented, which includes a protection substrate positioned within the cavity of the workpiece, coupled with a fluid conduit to direct a fluid that absorbs and dissipates laser energy, and a gas conduit to prevent fluid from entering the drilled hole, thereby reducing damage to the backwall surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser pulses are used to drill through a wall, then a hole is formed in the wall, but damage occurs to the backwall surface opposite the hole

Engineering Contradiction:
Improvehole formationVSAvoidbackwall damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

A protection substrate is introduced as an intermediary component positioned within the cavity between the laser path and the backwall surface. This substrate absorbs and dissipates the laser energy that would otherwise damage the backwall, while being easily replaceable after use.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protection substrate is designed as a disposable, low-cost component that is consumed during the laser drilling process. After absorbing laser energy and protecting the backwall, the substrate is replaced rather than reused, eliminating the need for complex protection systems.

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

2Object-affected harmful factors

If a protection substrate is positioned within the cavity to protect the backwall, then backwall damage is prevented, but the device complexity increases

Engineering Contradiction:
Improvebackwall protectionVSAvoidprotection system structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protection system is segmented into simple, modular components: a protection substrate, a support structure, and a fluid conduit. This segmentation allows for easy assembly, disassembly, and replacement of individual parts without affecting the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protection substrate automatically performs its protective function by being positioned in the laser path, eliminating the need for active control systems. The fluid conduit provides cooling and debris removal passively, reducing the need for complex active management.

Inventive Principle:
Principle #25Self-service

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

The system effectively prevents or minimizes damage to the backwall surface by absorbing and reflecting laser energy, maintaining the integrity of the workpiece and preventing unwanted holes or structural degradation during laser machining.

Implementation Method 1

a fluid conduit to direct a fluid that absorbs and dissipates laser energy

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

The system effectively prevents or minimizes damage to the backwall surface by absorbing and reflecting laser energy

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2788142B1Methods and systems for use in laser machining
Publication Date: 2020.02.26 GENERAL ATOMICS CO
  • EP2788142B1 patent drawingFigure 1~2
  • EP2788142B1 patent drawingFigure 3
  • EP2788142B1 patent drawingFigure 4

AI summary

The present embodiments providing methods, systems and apprartuses of protecting a surface during laser machining. In some embodiments, a method of protecting a surface during laser machining comprises: directing a fluid 938 into a cavity 318 of an object 320 being laser machined, where the fluid does not have laser absorption properties; and directing a plurality of laser pulses 324 at a wall 332 of the object being laser machined, where the laser pulses are configured to form a hole 330 through the wall 326 such that at least one laser pulse passes through the hole and enters the cavity while the fluid is directed into the cavity such that the laser pulse is incident on the fluid and a surface 612 together in order to inhibit backwall damage.