Laser Cavity Temperature Control for Turbine Drilling

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Solution Overview

Problem

Existing pulse laser drilling technologies for turbine engine parts are inefficient due to unstable temperature control, leading to suboptimal orifice geometry and increased microcracking, limiting their usage duration and quality.

Innovation Solution

Implementing a method to servo-control the temperature of the laser cavity based on the characteristics of the part and orifices to be drilled, optimizing operating parameters such as pulse frequency, duration, and power percentage, ensuring consistent cavity temperature within ±3°C to maintain drilling quality and extend device lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If prior art laser devices are used for making a small number of successive orifices, then the quality and repeatability of orifice shapes are maintained, but the device usage duration is limited and long rest periods are required

Engineering Contradiction:

Improveorifice shape quality and repeatabilityVSAvoiddevice usage duration

Core Design Contradiction:

Manufacturing precisionVSDuration of action of moving object

Solution Approach 1:

The patent implements a feedback control system that continuously monitors the laser cavity temperature and adjusts cooling parameters to maintain the temperature within the optimal range of 15°C to 30°C. This feedback mechanism allows the device to operate continuously without the quality degradation that previously occurred after a certain number of orifices, thereby extending the usable duration while maintaining manufacturing precision.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the operating parameters by actively controlling the cavity temperature within a specific range (15°C to 30°C) rather than allowing it to fluctuate freely. This parameter control enables the laser to maintain consistent beam quality and drilling performance over extended periods, resolving the contradiction between maintaining precision and extending operational duration.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the laser cavity temperature is not controlled, then the device can operate without temperature monitoring, but the orifice geometry becomes suboptimal and microcracking increases

Engineering Contradiction:

Improveoperation simplicityVSAvoidorifice geometry quality

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent implements a self-service temperature control system where the laser device automatically monitors its own cavity temperature and adjusts its cooling system accordingly. This self-regulating mechanism maintains optimal drilling conditions without requiring external intervention or complex external control systems, thus preserving ease of operation while dramatically improving manufacturing precision.

Inventive Principle:

Principle #25Self-service

3Productivity

If the laser cavity temperature exceeds the threshold, then the device must be rested for long periods, but continuous operation with temperature control is possible

Engineering Contradiction:

Improvedrilling throughputVSAvoiddevice stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The feedback control system continuously monitors cavity temperature and dynamically adjusts cooling parameters to prevent temperature excursions above the threshold. This enables continuous operation without the long rest periods previously required, thereby increasing productivity while maintaining device stability through active temperature management.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system takes preliminary action by proactively cooling the cavity before temperature thresholds are reached. The feedback control anticipates temperature rise during continuous operation and adjusts cooling in advance, preventing the conditions that would otherwise require device rest periods and maintaining both productivity and reliability.

Inventive Principle:

Principle #10Preliminary 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 approach enhances the stability and repeatability of orifice drilling, reducing microcracking and extending the usable duration of the laser generator by maintaining optimal drilling conditions, allowing for longer and more reliable operation.

Implementation Method 1

drilling a part, in particular a turbine engine part, by means of a pulse laser generator having a cavity (of controlled temperature) in which there is mounted a solid bar enabling a laser beam to be generated

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

the laser cavity also has a temperature sensor that is connected to detection means for warning an operator when the temperature of the cavity reaches a certain threshold. In order to avoid the laser cavity reaching the threshold, it is cooled while it is in operation

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS9713855B2Method and device for drilling a workpiece with laser pulses

Publication Date: 2017.07.25 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A method of drilling a part, or a turbine engine part, by a pulse laser generator including a cavity in which there is mounted a solid bar for generating laser pulses, the method including determining values of a plurality of operating parameters of the laser generator for forming orifices of predetermined diameter in the part, and taking account, among the parameters, of a setpoint value for the temperature of the laser cavity, which value is determined as a function of characteristics of the orifices to be drilled.