Polygonal Laser Scanner for Coating Removal
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Solution Overview
Problem
Current laser coating removal systems face limitations in achieving high power handling, efficient coating removal rates, and minimizing substrate alteration for large areas and delicate substrates, with existing oscillatory scanners being limited in scan speed and power handling, and lacking effective solutions for thermal management and contaminant exclusion.
Innovation Solution
A polygonal laser scanner system with a rotating multi-faceted mirror and reimaging optics, combined with a camera and strobe assembly for real-time imaging and power adjustment, and a gas flow system for contaminant exclusion, capable of handling up to 10 kW of power and achieving high scan speeds without substrate alteration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oscillatory scanning mirrors are used for coating removal, then coating removal is achieved, but scan speed is limited to less than 10 m/s and dead zones occur at the end of the scan
Solution Approach 1:
The patent transitions from static oscillatory mirrors to a dynamic rotating polygonal mirror system. The polygonal mirror rotates continuously at high speed, dynamically scanning the laser beam across the surface without dead zones. This dynamic approach enables scan speeds exceeding 10 m/s while maintaining continuous coverage throughout the scanning area.
Solution Approach 2:
The rotating polygonal mirror implements periodic scanning action through its continuous rotation, with each facet sequentially directing the laser beam across the treatment area. This periodic motion eliminates the dead zones associated with oscillatory mirrors by maintaining constant forward motion and systematic overlap between successive scan passes.
2Productivity
If high laser power (5-10 kW) is used for large area coating removal, then coating removal rate increases, but thermal damage and substrate alteration occur
Solution Approach 1:
The system performs preliminary actions by using high-speed scanning to rapidly move the laser beam across the surface, limiting the duration of thermal exposure at any single location. The gas flow system also performs preliminary cooling and contaminant removal before excessive heat accumulation can occur, preventing thermal damage while maintaining high power operation.
Solution Approach 2:
The continuous rotation of the polygonal mirror ensures uninterrupted scanning action, maintaining constant laser beam movement across the surface. This continuous action prevents localized heat buildup by ensuring that no single area remains under the laser beam longer than necessary, thereby enabling high power operation without substrate alteration.
3Object-affected harmful factors
If gas flow is used for contaminant exclusion, then contaminants are removed, but system complexity increases
Solution Approach 1:
The gas flow system acts as an intermediary between the laser processing zone and the surrounding environment. By introducing a controlled gas flow field, the system mediates contaminant removal and thermal management without requiring complex mechanical barriers or additional active control systems, thereby achieving contaminant exclusion with relatively simple implementation.
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 achieves efficient coating removal with high power handling and minimal substrate alteration, maintaining precise control over coating removal rates and thermal management, while effectively excluding contaminants and optimizing beam cross-over regions for improved performance.
Implementation Method 1
a laser source operative to generate a laser beam and direct the laser beam onto a work surface
Implementation Method 2
uses pulsed light sources to remove coatings from substrates by ablation
Implementation Method 3
a photodetector circuit senses reflected light from the surface under ablation
Implementation Method 4
a strobe assembly for illuminating the work surface and overwhelming light generated by the laser beam interaction with the work surface
Implementation Method 5
means for providing an outward flow of gas though the aperture for preventing contaminants from entering the interior of the scanner
Data Source
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AI summary
A system for removing a coating from a surface is provided. This system includes a laser scanner, wherein the laser scanner further includes at least one laser source, wherein the at least one laser source is operative to generate at least one laser beam, and wherein the laser beam is directed onto a work surface by the laser scanner; and a controller for operating the laser scanner. The controller further includes an imaging device for imaging the work surface; a lighting device for illuminating the work surface and overwhelming light generated by the interaction of the laser beam with the work surface; and a processor for processing information collected by the imaging device and adjusting the power output of the at least one laser source, if and when desirable or necessary.