Laser Welding Feedback Control for Reflectivity Compensation
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Solution Overview
Problem
Current Through Transmission Infrared (TTIr) welding techniques require manual and laborious adjustment of laser output for precise welding, lacking efficient control mechanisms to ensure consistent results.
Innovation Solution
Implementing a closed-loop feedback control system using an optical sensor and control module to automatically compensate for part and tool reflectivity, allowing for precise calibration and adjustment of laser power delivery to the weld zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual adjustment of laser output is used, then welding can be performed, but the process is laborious and time-consuming
Solution Approach 1:
The patent implements a closed-loop feedback control system where a photodiode detects the actual laser power output and feeds this information back to a control module. The control module automatically adjusts the laser driver to maintain the desired power level, eliminating manual trial-and-error adjustments and significantly improving welding productivity while reducing operational complexity
Solution Approach 2:
The system performs self-adjustment by automatically compensating for laser power variations through the feedback loop. The control module continuously monitors the actual output and makes real-time corrections without operator intervention, allowing the system to self-regulate and maintain consistent welding quality
2Manufacturing precision
If manual adjustment is used to achieve desired laser heating, then welding can be performed, but it requires trial and error process
Solution Approach 1:
The feedback control system using a photodiode provides real-time measurement of actual laser power delivered to the workpiece. This immediate feedback allows the control module to make precise adjustments to maintain consistent heating conditions, eliminating trial-and-error processes and reducing the time required to achieve desired weld quality
Solution Approach 2:
The patent replaces manual mechanical adjustment mechanisms with an automated electronic control system. The photodiode-based optical detection system substitutes for manual visual inspection and adjustment, providing precise, repeatable measurements and control that eliminate variability associated with manual operations
3Measurement precision
If closed-loop feedback control is implemented, then laser output can be controlled precisely, but device complexity increases
Solution Approach 1:
While feedback control does increase device complexity, the patent implements a relatively simple feedback loop using a photodiode and control module that integrates with existing laser hardware. The complexity added is minimal compared to the significant improvement in measurement precision and weld quality control achieved
Solution Approach 2:
The photodiode serves as an intermediary device that converts optical laser power measurements into electrical signals that can be processed by the control module. This intermediary approach allows for precise measurement and control without requiring direct modification of the laser source itself, thereby limiting the increase in overall system complexity
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
Enables quick and accurate control of laser power, reducing manual intervention and ensuring consistent weld quality by automatically accounting for reflectivity and absorption, thereby improving the efficiency and reliability of the welding process.
Implementation Method 1
Feedback control system 12 comprises an optical sensor 16 positioned downstream from laser source 14
Implementation Method 2
The second plastic part is often referred to as absorptive piece, since this piece generally absorbs the radiative energy of the laser beam to produce heat in the welding zone
Implementation Method 3
This heat in the welding zone causes the transmissive piece and the absorptive piece to be melted and thus welded together
Implementation Method 4
control module 17 operably coupled in electrical communication with optical sensor 16 for receiving real-time laser intensity information from laser source 14 and operably coupled in electrical communication with laser source 14 for controlling an output intensity of laser source 14
Data Source
AI summary
A feedback control system for controlling a laser source. The feedback control system includes a laser source outputting laser energy and an optical sensor detecting the laser energy. The optical sensor outputs a measured signal in response to a measured amount of the laser energy. The system further includes an optical device receiving the laser energy and directing the laser energy to a predetermined location. The optical device reflects a first portion of the laser energy toward the optical sensor. A controller receives the measured signal from the optical sensor and calculates the amount of the first portion of the laser energy. The controller then adjusts the laser source to correct for the losses associated with the first portion of the laser energy reflecting from the optical device to obtain a predetermined amount of laser energy at the predetermined location.