Pulse Laser Welding Control for Stable First-Weld Output
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Solution Overview
Problem
High-speed pulse welding for multiple welds on small workpieces like disk device suspensions often results in unstable output for the first weld, leading to potential errors, and pre-shot techniques can decrease productivity by requiring workpiece stoppage and extra time.
Innovation Solution
A laser welding apparatus and method that supplies preliminary excitation power to the excitation light source for a longer duration than the pulse width before the first weld, followed by a predetermined interval, ensuring stable energy injection for the first weld without the need for a pre-shot, using a control unit and galvano scanner for precise beam focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-shot of laser beam is carried out before welding the first weld, then welding errors in the first weld can be prevented, but productivity decreases due to extra time spent and workpiece stoppage
Solution Approach 1:
The invention applies preliminary action by supplying preliminary excitation power to the excitation light source before welding the first weld. This pre-excites the laser medium to a stable state, ensuring stable laser beam output without requiring actual pre-shot welding or workpiece stoppage. The preliminary excitation power is supplied over a preliminary supply time longer than the pulse width of the drive power, and a predetermined interval elapses before welding begins, achieving reliable welding quality while maintaining high productivity.
2Productivity
If high-speed pulse welding is applied to weld more than one hundred welds per second, then welding efficiency increases, but the output of laser beam on the first weld becomes unstable
Solution Approach 1:
The invention resolves this contradiction by performing preliminary excitation of the laser medium before high-speed pulse welding begins. The control unit supplies preliminary excitation power to the excitation light source over a duration longer than the pulse width of subsequent weld pulses, allowing the laser medium to reach a stable excited state. This ensures that when high-speed welding commences, the laser beam output is stable from the first weld onward, maintaining both high productivity and welding quality.
Solution Approach 2:
The invention employs periodic action through the structured timing of preliminary excitation followed by high-speed pulse welding. The control unit implements a periodic cycle where preliminary excitation power is supplied for a specific duration, followed by a predetermined interval, and then high-speed pulse welding proceeds at more than one hundred pulses per second. This periodic structure ensures the laser medium is consistently prepared for each welding cycle, maintaining stable output throughout high-speed operation.
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 prevents welding errors in the first weld while maintaining high productivity by stabilizing the laser beam output and focusing, even on small workpieces without the need for pre-shot irradiation, thus ensuring consistent quality and efficiency.
Implementation Method 1
an excitation light source which injects excitation energy into the laser medium while drive power is supplied thereto
Implementation Method 2
a laser medium which emits a laser beam for the welds while excitation energy is injected thereto
Data Source
AI summary
A laser welding apparatus includes a laser medium, an excitation light source and a control unit. The control unit supplies drive power to the excitation light source to inject excitation energy to the laser medium. The control unit supplies preliminary excitation power, which is smaller than pulsed drive power, to the excitation light source over a preliminary supply time, which is longer than a pulse width of the drive power before welding the first weld to be welded. After the preliminary supply time elapses and then an interval, the pulsed drive power is supplied to the excitation light source to weld the first weld.