Diffractive Optical Element for Laser Welding Seam Width
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Solution Overview
Problem
Existing laser processing methods struggle to achieve a wider weld seam than the diameter of the laser light spot, requiring inefficient scanning or misalignment of the focal plane, leading to increased production costs and process times.
Innovation Solution
A method using a diffractive optical element to split and recombine laser beams, increasing the diameter of the laser light spot to match the desired weld seam width, allowing for a single processing point with adjustable beam profiles and power distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the laser beam is focused to a small spot size for precise processing, then the energy density is high, but the weld seam width is limited to the spot diameter
Solution Approach 1:
The laser beam is divided into multiple partial beams by the diffractive optical element, creating an array of focused spots that collectively form a wider effective weld seam while each individual spot maintains high energy density for precise processing
2Length of moving object
If the focal plane is misaligned to increase weld seam width, then the weld seam width increases, but the energy transfer efficiency decreases
Solution Approach 1:
Instead of misaligning a single focused spot, the invention segments the beam into multiple spots arranged in an array that spans the desired weld seam width, with each spot remaining sharply focused at the correct focal plane, thus maintaining energy transfer efficiency while achieving the required width
Solution Approach 2:
The invention transitions from a single-dimensional focused spot to a two-dimensional array of focused spots, enabling width control in the lateral dimension while maintaining focal precision in the depth dimension
3Length of moving object
If repeated scanning is performed to create wider weld seams, then the weld seam width increases, but the production time increases
Solution Approach 1:
The weld seam width is achieved in a single pass by using a segmented beam structure with multiple parallel focal spots that cover the entire required width simultaneously, eliminating the need for repeated scanning operations and reducing production time
Solution Approach 2:
Multiple partial beams are combined in parallel to form a composite beam structure that delivers the entire weld seam energy distribution in one processing pass, merging the functionality of what would otherwise require multiple sequential scans
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 the creation of a wider weld seam without the need for repeated scanning or misalignment, optimizing energy transfer and reducing production costs by maintaining the focal plane and interaction surface coincidence.
Implementation Method 1
an active optical element for adjusting the beam diameter of the laser beam, with the active optical element being designed as a diffractive optical element that splits the original laser beam into a bundle of partial laser beams
Implementation Method 2
at least one focusing lens for converging the laser beam
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
Adjusting a laser light spot (12) of high intensity for laser processing of workpieces (7), preferably for laser welding of plastic workpieces to be joined using a laser arrangement (1) with laser emitting at least a laser beam (6), at least one focusing lens (4) for converging the laser beam, and an optical active element for adjusting the beam diameter of the laser beam, comprises forming optical active element as a diffractive optical element, which decomposes the original laser beam in a radiation beam from laser beam part, which are directed onto the workpiece. Adjusting a laser light spot (12) of high intensity for laser processing of workpieces (7), preferably for laser welding of plastic workpieces, which are to be joined using a laser arrangement (1) with laser emitting at least a laser beam (6), at least one focusing lens (4) for converging the laser beam, and an optical active element for adjusting the beam diameter of the laser beam, comprises forming optical active element as a diffractive optical element, which decomposes the original laser beam in a radiation beam from laser beam part, which are directed onto the workpiece. The diameter of the laser light spot on the workpieces, preferably in the focal plane and transverse to the extending direction of the focal plane is increased compared to the diameter of the original laser beam during entry into the diffractive optical element to a desired dimension using the diffractive optical element, where the partial laser beams generated from original laser beam is directed with overlapping and/or gaps of any shape to the workpieces and to a total laser beam, which respectively acts on a single processing point. The number and the diameter of the partial laser beams and the overall diameter of the total laser beam are determined through the diffractive optical element. An independent claim is also included for a laser arrangement for laser processing of workpieces, where (a) the focusing lens produces the laser light spot of high intensity on the workpiece and the active element is formed as the diffractive optical element, which splits the original laser beam into a beam of partial laser beams, (b) partial laser beams generated by the diffractive optical element forms the resultant beam profile, which is directed onto the focal plane, (c) the diffractive optical element increases the diameter of the laser light spots on the work pieces, preferably in the focal plane and transverse to the extending direction of the focal plane, compared to the diameter of the original laser beam during entry into the diffractive optical element to the desired dimension, (d) the generated partial laser beams are brought together to the total laser beam, which exhibits overlapping and/or gaps of any form and respectively directed to the single processing point of the workpiece.