Composite Laser Beam Welding of Coated Plates Without Spatter
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Solution Overview
Problem
Laser welding of overlapping metal plates with coatings faces challenges in kerf control and self-burning, leading to poor quality welds and the need for expensive purifying processes due to uneven energy distribution and pressure issues.
Innovation Solution
A laser processing apparatus and method utilizing a composite laser beam comprising a center beam with a circular cross-section and an annular ring beam, directed through a multi-core optical fiber, to control energy distribution and release pressure, allowing for precise welding of coated plates without coating spatter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single laser beam is used for welding overlapping coated plates, then the coating material vaporizes and causes pressure that pushes plates apart or creates spatter, but using a composite laser beam with center and annular cores enables pressure release through the center beam while maintaining welding quality through the annular beam
Solution Approach 1:
The laser beam is segmented into two distinct functional components: a center beam (circular or hollow circular cross-section) and an annular beam (ring-shaped cross-section). Each beam type performs a specific function - the center beam releases pressure by vaporizing coating material, while the annular beam provides welding heat - thereby resolving the contradiction between maintaining welding quality and eliminating harmful spatter and pressure effects.
2Manufacturing precision
If the plates are forced together with no gap using a jig, then welding can proceed, but vaporizing coating material blows out through the welding seam causing impurity on the top plate requiring expensive purifying processes
Solution Approach 1:
The harmful function of coating vaporization (pressure and spatter) is extracted and separated from the useful welding function. The center beam specifically targets and removes coating material to release pressure, while the annular beam delivers welding heat without causing excessive spatter, thus extracting the harmful effect and directing it through a controlled path that prevents contamination of the weld zone.
3Strength
If there is no gap between plates, then welding can proceed, but coating vaporization causes pressure pushing plates apart; if there is gap, then pressure is reduced, but top plate may burn through
Solution Approach 1:
Different regions of the laser beam system are assigned different functional qualities: the center beam region is optimized for pressure release (higher energy concentration on coating), while the annular beam region is optimized for welding (distributed heat for molten pool formation). This local differentiation of beam function allows simultaneous achievement of strong welds and precise kerf control without requiring gap adjustment.
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
The hybrid laser beam approach achieves deeper weld penetration, reduces hardening effects, and prevents coating spatter, enabling efficient welding of coated plates with improved quality and reduced post-processing requirements.
Implementation Method 1
at least one first optical feed fiber with a first laser beam, at least one second optical feed fiber with a second laser beam; beam combining means connected to said first and second feed fibers and to a multi-core optical fiber
Implementation Method 2
the laser beam is typically condensed through a condenser lens into a spot of 100-500 μm to increase energy density
Implementation Method 3
the laser beam is typically condensed through a condenser lens into a spot of 100-500 μm to increase energy density and instantaneously heat the workpiece to a metal melting point of 1500 degrees or over so that the workpiece melts
Implementation Method 4
a one-micrometer waveband laser beam with a Gaussian beam... realizes a very high optical energy intensity and absorbance on a metallic work
Implementation Method 5
an assist gas may be fed to prevent oxidation of the molten metal
Implementation Method 6
the laser beam 2 causes the coating material between the plates to vaporize and the pressure causes the plates apart from each other
Data Source
AI summary
The invention concerns an apparatus and a method for laser processing. There is provided at least one first laser beam from at least one first optical feed fiber connected to at least one first laser device and at least one second laser beam from at least one second optical feed fiber connected to at least one second laser device. Said first and second laser beams are combined in a multi-core optical fiber. Said first core of said multi-core optical fiber has a circular cross-section, and said second core has an annular shape concentric to said first core. A composite laser beam comprising first and second output beams is directed from said multi-core optical fiber to a workpiece with overlapping elements to be welded.