Laser Machining Apparatus Reflected Light Control
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Solution Overview
Problem
Laser machining is often interrupted by strong reflected light, which can damage the laser oscillator and hinder stable production, especially when machining conditions are unknown or incorrectly inputted, and when reflectance varies due to surface conditions or material properties.
Innovation Solution
A laser machining method that initially outputs a low-power laser beam to measure reflected light, selects suitable power for melting or oxidizing based on measured values, and adjusts power and focal position to control reflected light, using databases to associate reflectance values with appropriate laser powers and maximum output limits, ensuring the laser oscillator operates within safe parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high laser power is used to perform laser machining, then machining efficiency is improved, but reflected light may damage the laser oscillator
Solution Approach 1:
The patent applies preliminary action by performing preparatory machining at low laser power before the main high-power machining. This preliminary step creates initial penetration or modifies the surface to reduce reflectance, thereby preventing damage to the laser oscillator when high power is subsequently applied. The control unit manages this two-stage process to ensure safe operation.
Solution Approach 2:
The patent implements periodic action through pulse-width modulation of the laser beam. By alternately applying low-power pulses (for safety and preliminary processing) and high-power pulses (for efficient machining), the system achieves both oscillator protection and machining efficiency. The duty cycle and pulse timing are controlled to optimize both safety and productivity.
2Reliability
If low laser power is used to avoid reflected light damage, then laser oscillator safety is improved, but machining efficiency deteriorates
Solution Approach 1:
The patent uses low laser power in a preliminary stage to safely initiate processing and reduce surface reflectance. Once the preliminary machining is complete and the surface is more absorptive, the system transitions to high-power machining. This staged approach ensures oscillator safety during the critical initial phase while maintaining overall machining efficiency.
Solution Approach 2:
The system employs periodic alternation between low-power and high-power laser pulses. Low-power pulses are used intermittently to manage reflectance and protect the oscillator, while high-power pulses are applied when conditions are safe. This periodic modulation optimizes both safety and productivity throughout the machining process.
3Reliability
If preparatory machining is performed to reduce reflected light, then laser oscillator safety is improved, but machining time increases
Solution Approach 1:
The patent merges the preparatory machining and main machining operations into a single continuous process controlled by pulse-width modulation. Rather than completing all preparatory work before main machining, the system interleaves low-power and high-power pulses, combining the functions of surface preparation and material removal in one integrated operation. This reduces total machining time while maintaining oscillator safety.
Solution Approach 2:
By using periodic pulse sequences that alternate between low-power (preparatory) and high-power (main machining) modes, the system performs both preparatory and main machining functions simultaneously over time. This eliminates the need for separate preparatory and main machining stages, thereby reducing total machining time while ensuring oscillator protection during low-power phases.
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 prevents damage to the laser oscillator by stabilizing the machining process, allowing for accurate determination of suitable laser power and preventing interruptions due to reflected light, thereby ensuring stable and productive laser machining.
Implementation Method 1
outputs a laser beam from a cutting head to a workpiece and performs laser machining
Implementation Method 2
laser power high enough to melt or oxidize the workpiece
Implementation Method 3
A very strong reflected light sent back to the laser oscillator would destroy the laser oscillator in an instant
Data Source
AI summary
A laser machining method includes the steps of: outputting a laser beam to the workpiece at a laser power low enough not to melt or oxidize the workpiece to measure reflected light of the laser beam; selecting a laser power suitable for melting or oxidizing the workpiece based on a measured value of the reflected light; determining whether or not the workpiece can be melted or oxidized based on the selected laser power; when the workpiece can be melted or oxidized, outputting a laser beam to the workpiece at a laser power high enough to melt or oxidize the workpiece; outputting again a laser beam to the workpiece at the low laser power to measure reflected light of the laser beam; and checking the degree of the melting or oxidization of the workpiece based on a measured value of the reflected light to determine whether or not to start laser machining.