Laser Processing with Pulse-Assisted Plasma Light Detection
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Solution Overview
Problem
Laser processing apparatuses using fiber or YAG lasers struggle to accurately grasp process conditions and states due to the low absorption of laser beams by ionized plumes, resulting in insufficient plasma light production for quality determination.
Innovation Solution
A laser processing apparatus that combines a continuous process laser beam with a pulse laser beam having a higher peak energy density, directed to the workpiece through separate optical systems, to enhance plasma light intensity for accurate detection and feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a fiber laser or YAG laser is used as the process laser light source, then the laser processing can be performed with continuous energy density, but the plasma light intensity is insufficient for accurate process monitoring
Solution Approach 1:
The patent applies periodic action by introducing a pulse laser beam with peak energy density higher than the continuous process laser beam during a specific period (second period) that is part of the first period. This periodic high-intensity pulse action temporarily enhances plasma light generation, enabling accurate process monitoring while maintaining continuous processing capability. The pulse laser operates periodically within the continuous process, creating moments of enhanced plasma emission for detection purposes.
2Productivity
If the laser beam wavelength is shorter (fiber laser or YAG laser), then the laser processing efficiency is improved, but the absorption by ionized plume is reduced
Solution Approach 1:
The patent applies parameter changes by varying the energy density parameter of the laser beam over time. It uses a continuous process laser beam with stable energy density for efficient processing, then periodically introduces a pulse laser beam with higher peak energy density to enhance plasma generation. This temporal variation in energy density parameter allows the system to achieve both efficient processing (during continuous phase) and adequate plasma light for monitoring (during pulse phase).
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 configuration allows for more accurate detection of plasma light intensity, enabling precise determination of process conditions and states, even when parameters vary, thereby improving the quality control of laser processing.
Implementation Method 1
a process laser light source operable to generate a process laser beam having a continuous energy density during a first period of time, a first optical system that directs the process laser beam to a surface of a workpiece
Implementation Method 2
When the laser beam passes through the generated plume, the plume is overheated so as to produce plasma light
Implementation Method 3
an optical detection portion operable to detect plasma light produced at the process portion of the workpiece
Data Source
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AI summary
The present invention provides a laser processing apparatus that enables process conditions or a process state to be grasped with accuracy. A laser processing apparatus 1 has a process laser light source 20 operable to generate a process laser beam CL having a continuous energy density during a certain period of time, a first optical system 31, 32 that directs the process laser beam CL to a surface of a workpiece W, a pulse laser light source 50 operable to generate a pulse laser beam PL having an energy density with a peak value that is higher than the energy density of the process laser beam CL, a second optical system 61, 62 that directs the pulse laser beam PL to a process portion P of the workpiece W, and an optical detection portion 80 operable to detect plasma light produced at the process portion P of the workpiece W.