OCT-Guided Beam Machining Monitoring With External Signal Sync
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Solution Overview
Problem
Existing machining processes using high-energy beams for welding face challenges in reliable and accurate monitoring due to temporal jitter in signal allocation and the inability to accurately determine threshold values for process control, especially when the welding wire and molten material obscure the workpiece surface, leading to unreliable OCT measurements.
Innovation Solution
A method and device that utilize an external signal independent of machining and measurement control signals to accurately determine measurement points and threshold values, incorporating an optical coherence tomograph for real-time monitoring, and a control unit to evaluate these points against threshold values, ensuring precise process monitoring and regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If OCT measurement beam is used to monitor weld seam, then three-dimensional depth measurement is achieved, but temporal jitter in signal allocation reduces measurement accuracy
Solution Approach 1:
The patent introduces an external reference signal as an intermediary to synchronize the OCT measurement beam with the machining beam. This reference signal serves as a mediator that eliminates temporal jitter by providing a common time reference for both beams, thereby improving the reliability of signal allocation while maintaining depth measurement accuracy
Solution Approach 2:
The system implements feedback by continuously monitoring the temporal alignment between the OCT measurement beam and machining beam using the external reference signal. This feedback mechanism allows real-time adjustment and synchronization, ensuring consistent measurement accuracy throughout the machining process
2Measurement precision
If target range is determined by evaluating profile at workpiece surfaces, then defect detection is enabled, but welding wire and molten material obscure the surface reference
Solution Approach 1:
The patent applies preliminary action by determining the target range before the welding wire and molten material obscure the workpiece surface. The system pre-establishes reference profiles and target ranges based on the initial workpiece geometry, enabling accurate defect detection even when the surface becomes obscured during the machining process
Solution Approach 2:
The system transitions from relying solely on two-dimensional surface profiles to utilizing three-dimensional OCT depth measurements. By incorporating the depth dimension, the system can determine target ranges and detect defects without being obscured by the welding wire or molten material on the surface
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 achieves high accuracy and reliability in machining process monitoring by eliminating temporal jitter and providing accurate threshold determination, enabling precise control of machining parameters such as penetration depth and weld seam quality.
Implementation Method 1
an optical coherence tomograph (OCT) is often used, by means of which there can be generated a measurement beam which is able to be coupled into the machining beam optics
Implementation Method 2
A high-energy machining beam in the form of a laser machining beam is thereby used to act on one or more workpieces or workpiece parts
Data Source
AI summary
The invention relates to a method for conducting and monitoring a machining process of a workpiece (10), in particular a welding process for joining the workpiece (10) to a further workpiece (10), by means of a high-energy machining beam (14), wherein the method comprises the following steps: generating a high-energy machining beam (14); projecting and/or focusing the machining beam (14) onto the workpiece (10), wherein, in accordance with a machining control signal, different machining regions of the workpiece (10) are machined; generating a measurement beam (16) by means of an optical coherence tomograph (18), wherein the measurement beam (16) is able to be coupled into the machining beam (14); determining measurement points (20) during the machining process by means of the optical coherence tomograph (18) using the measurement beam (16), in accordance with a measurement control signal; obtaining at least one external signal which is based on a measured variable and which is independent of a processing of the machining control signal and of the measurement control signal; generating an evaluation on the basis of the measurement points (20) and of the at least one external signal, which evaluation comprises a comparison of the measurement points (20) with at least one threshold value; monitoring the machining process on the basis of the evaluation.The invention relates further to a correspondingly configured device for conducting and monitoring a machining process of a workpiece (10).