Coaxial Core-Ring Laser Machining for Crack- and Spatter-Control
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Solution Overview
Problem
Laser machining of materials with different thermal conductivities, such as aluminum and copper, often results in hot cracks and spatter, especially during high-speed welding, due to the challenges in maintaining consistent machining quality and managing thermal conductivity differences.
Innovation Solution
A method and system that utilize a laser beam comprising a core beam and a ring beam, which are coaxially aligned and power-adjusted based on the position and properties of the workpiece, to control the machining process, preventing hot cracks and spatter by optimizing the laser power distribution along the machining path and wobble pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single laser beam is used for machining materials with different thermal conductivities, then the machining process is simple, but hot cracks and spatter occur due to inconsistent thermal distribution
Solution Approach 1:
The laser beam is segmented into a core beam and a ring beam that can be independently controlled. The core beam targets the center of the workpiece while the ring beam targets the peripheral regions, allowing differential power distribution to match the thermal conductivity variations across the material surface. This segmentation enables precise thermal management without requiring multiple separate laser sources.
Solution Approach 2:
Different regions of the workpiece receive different laser power densities tailored to their specific thermal conductivity characteristics. The center region (processed by core beam) and peripheral regions (processed by ring beam) are treated with locally optimized parameters, ensuring uniform thermal distribution across the entire machining area while preventing hot cracks and spatter.
2Productivity
If laser power is increased to maintain machining quality at higher speeds, then machining speed increases, but hot cracks and spatter worsen due to excessive thermal concentration
Solution Approach 1:
The laser beam structure dynamically adapts to the machining conditions through real-time power modulation of the core and ring beams. The system can switch between different power distribution modes and beam configurations based on the current machining speed and material properties, maintaining optimal thermal distribution across varying production rates without causing defects.
Solution Approach 2:
The laser processing parameters including power distribution, beam diameter, and focal position are continuously adjusted based on feedback from the machining process. By changing these parameters dynamically, the system maintains consistent machining quality at higher speeds while preventing thermal-related defects through optimized energy input.
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 enhances machining quality by reducing hot cracks and spatter, allowing for higher speed and more consistent welding of materials with varying thermal conductivities, such as high-strength steels, aluminum alloys, and copper, while maintaining optimal machining quality.
Implementation Method 1
the material of the workpiece is heated so much by the incident laser power in an interaction area that it melts or even evaporates
Implementation Method 2
the material of the workpiece is heated so much by the incident laser power in an interaction area that it melts or even evaporates
Implementation Method 3
the material of the workpiece is heated so much by the incident laser power in an interaction area that it melts or even evaporates
Data Source
AI summary
A method of laser machining a workpiece includes the steps of: radiating a laser beam onto at least one workpiece, the laser beam having a core beam and a ring beam extending coaxially with one another, wherein the laser beam is moved over the workpiece along a pre-determined machining path, and adjusting a laser power of the core beam and/or a laser power of the ring beam as a function of a position of the laser beam on the workpiece. An associated laser machining system is also disclosed.