Fluorescence-Based Measurement of Workpiece Geometry and Temperature in Laser Chemical Machining

Area of Science:

• Manufacturing Engineering
• Materials Science
• Optical Metrology

Background:

• Laser chemical machining (LCM) is a precise metal removal technique requiring controlled conditions.
• Current limitations in understanding LCM mechanisms hinder optimization of removal rate and quality.
• A need exists for in-situ monitoring of workpiece geometry and process parameters for quality control.

Purpose of the Study:

• To develop and validate a near-process measurement approach for laser chemical machining.
• To simultaneously assess machined workpiece geometry and process fluid temperature in-situ.
• To establish a foundation for future real-time quality control in LCM.

Main Methods:

• A fluorescence-based optical measurement technique was employed.
• In-situ measurement of 3D geometry of LCM-produced structures was performed.
• In-situ temperature measurement of the electrolyte solution was conducted.

Main Results:

• The developed approach demonstrated robustness in measuring 3D geometry, even with optical obstructions like air bubbles.
• Systematic measurement errors (edge artifacts) were identified in geometry measurements, necessitating signal model refinement.
• Precise temperature measurements of the electrolyte were achieved with low random (<1°C) and systematic (<1.4°C) errors.

Conclusions:

• The fluorescence-based method shows promise for in-situ monitoring in LCM.
• The technique can simultaneously measure geometry and temperature, supporting process control.
• Further refinement of the signal model is required to address observed geometric measurement errors.