Laser Weld Beam Oscillation to Prevent Hot Cracks
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Solution Overview
Problem
Existing welding methods face challenges in preventing hot cracks during the joining of workpieces, particularly in materials sensitive to hot cracks or in crack-sensitive geometries, such as aluminum, where conventional techniques fail to ensure a strong and crack-free weld seam.
Innovation Solution
A method involving a processing beam, like a laser beam, that moves along a two-dimensional movement path with periodic oscillations superimposed on the feed direction, featuring at least one stopping point where the speed component in the transverse direction is zero, allowing for targeted interaction time and power control to enhance weld quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding methods are used on hot-crack sensitive materials, then welding speed and productivity are maintained, but hot cracks occur during penetration and through-welding
Solution Approach 1:
The patent applies periodic oscillation of the laser beam in a figure-eight pattern, creating cyclic heating and cooling zones that prevent hot crack formation. The beam oscillates with specific frequencies and amplitudes in transverse and feed directions, transforming continuous welding into a periodic process that eliminates crack-prone conditions while maintaining productivity.
Solution Approach 2:
The invention introduces dynamic motion patterns for the laser beam, combining feed direction movement with superimposed oscillation in transverse direction. The beam position varies continuously through programmed trajectories, creating dynamic heat distribution that prevents stagnant molten pools and associated cracking.
2Reliability
If laser beam oscillation is applied to prevent hot cracks, then weld quality improves, but process complexity increases
Solution Approach 1:
The control device integrates multiple functions: it manages the basic feed motion of the laser beam along the weld seam, simultaneously superimposes oscillation in the transverse direction, and coordinates beam deflection. This multi-functional control system eliminates the need for separate oscillation mechanisms, reducing overall device complexity while achieving crack-free welds.
Solution Approach 2:
The patent replaces mechanical oscillation systems with optical beam deflection controlled by a control device. Instead of physically moving the laser source or workpiece with complex mechanical mechanisms, the invention uses electronic control to deflect the beam along figure-eight trajectories, simplifying the mechanical system while maintaining precise motion control.
3Reliability
If figure-eight oscillation path is used, then hot crack resistance increases, but energy consumption increases
Solution Approach 1:
The figure-eight oscillation pattern ensures continuous laser beam contact with the workpiece surface throughout the oscillation cycle, eliminating idle positions where energy would be wasted. The beam continuously deposits energy along the weld path while oscillating, maintaining productive action throughout the entire motion cycle and improving energy utilization efficiency.
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 reduces the occurrence of hot cracks and improves the mechanical connection between workpieces by optimizing the interaction time and heat distribution, resulting in a stronger weld seam, especially beneficial for materials like aluminum.
Implementation Method 1
forming a weld seam by moving a processing beam, in particular a laser beam, and the at least two workpieces relative to each other
Implementation Method 2
a processing beam, in particular a laser beam... moving the processing beam and the at least two workpieces relative to each other
Implementation Method 3
a beam deflection device for deflecting the processing beam... control device for controlling the beam deflection device to generate a periodic movement
Data Source
Figure 1
Figure 2a~4b
Figure 5a~6b
AI summary
The invention relates to a method for joining at least two workpieces (2a, 2b), having the steps of: forming a welding seam (7) by moving a machining beam, in particular a laser beam (3), and the at least two workpieces (2a, 2b) relative to one another along an advancing direction (Y), wherein the movement of the machining beam and the two workpieces (2a, 2b) relative to one another is superimposed with a periodic movement in a preferred two-dimensional movement path, which extends in a transverse direction (X) perpendicularly to the advancement direction (Y) and preferably additionally in the advancement direction (Y). The movement path has at least one stopping point (H), where a speed component of the periodic movement in the transverse direction (X) is null, between two reversal points in the transverse direction (X). The invention also relates to a computer program product and to a device for carrying out the method.