Laser Pulse Waveform Control for Cutting Quality
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Solution Overview
Problem
Laser processing methods face challenges in enhancing dividing performance, leading to reduced productivity due to variations in pulse energy and fracture extension, which affects the quality of the cutting process.
Innovation Solution
A laser processing method that optimizes pulse waveforms by setting the half width and bottom width of laser pulses equal, with specific waveforms (saw-blade shapes) depending on pulse energy levels to enhance dividing performance, and adjusts pulse energy to prevent damage or expose fractures as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous wave laser is used for processing, then the laser beam can be continuously applied to the workpiece, but the laser energy is wasted and processing speed is reduced due to the need to move the laser beam back to the starting position
Solution Approach 1:
The patent employs periodic pulsed laser action instead of continuous wave operation. The laser operates in cycles of irradiation and pause, where the beam is directed to the workpiece only during the irradiation period and positioned at the end position during pause periods. This periodic operation eliminates the waste of continuously applying laser energy when the beam is repositioning, thereby improving both energy efficiency and processing speed.
2Productivity
If the laser beam is moved back to the starting position during processing, then the next processing cycle can begin, but processing time is lost and overall productivity decreases
Solution Approach 1:
The patent implements preliminary positioning where the laser beam is pre-positioned at the end position (last irradiation position) during the irradiation phase itself, rather than returning to the start position. This preliminary action of being already positioned at the end location eliminates the need for time-consuming return trips, allowing the next processing cycle to begin immediately, thus improving processing efficiency and reducing time loss.
3Productivity
If high laser power is used to increase processing speed, then productivity improves, but the laser beam may deviate from the intended path and hit adjacent areas causing harmful effects
Solution Approach 1:
The patent applies local quality control by concentrating the high-power laser beam precisely at the specific irradiation position on the workpiece surface. The beam is directed to hit only the intended local area (dents or crevices) rather than spreading to adjacent regions. This localized application of high power achieves fast processing speed while preventing harmful effects on surrounding areas through precise spatial control of the beam's impact location.
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 significantly improves dividing performance according to required quality, reducing takt time and optimizing fracture extension, while minimizing damage to the opposite surface during laser processing.
Implementation Method 1
a laser beam is moved back to a starting position for next processing
Implementation Method 2
When a laser beam is moved to a workpiece for processing
Data Source
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AI summary
To provide a laser processing method which is capable of enhancing the dividing performance according to a required quality. By irradiating an object to be processed with a laser light L having a pulse waveform in which its half width and its bottom width are equal to one another, a plurality of modified spots are formed along a line to cut inside the object, and a modified region is formed with the plurality of modified spots. Here, a laser light source 101 controls a drive power source 51 by a laser light source controller 102, to switch among a pulse waveform among first to third pulse waveforms according to a PE value of the laser light L. In the case of a low PE value, a first pulse waveform formed such that a peak value is located on its first half side and into a saw-blade shape is set as the pulse waveform, and in the case of a high PE value, a second pulse waveform formed such that a peak value is located on its latter half side and into a saw-blade shape is set as the pulse waveform.