Laser Additive Manufacturing Alignment via Offset Step Measurement
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Solution Overview
Problem
Existing methods for aligning lasers in multiple laser metal additive manufacturing systems are inaccurate due to the use of low power testing, two-dimensional alignment without consideration of three-dimensional melt pools, and imprecise calibration techniques, leading to unsmooth outer surfaces in the overlap region.
Innovation Solution
A method that forms a test structure at full operational power in three dimensions within the overlap region, using two sets of layers formed exclusively by each laser to measure the offset step and apply the dimension of the offset as an alignment correction to align the lasers accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional low power alignment test is used, then alignment correction can be applied, but the alignment precision is insufficient leading to unsmooth outer surfaces
Solution Approach 1:
The patent changes the power parameter from low power (conventional) to full operational power (high power) during the alignment test. This parameter change enables the laser to create actual melt pools under operational conditions, allowing for accurate measurement of alignment errors that affect outer surface smoothness. The high power test reveals misalignment issues that low power tests cannot detect.
Solution Approach 2:
The patent transitions from two-dimensional alignment testing (conventional) to three-dimensional melt pool formation (full operational power). By creating actual melt pools in the third dimension (depth), the test accurately captures the true alignment state of lasers, enabling precise correction of misalignment that causes surface irregularities.
2Ease of manufacture
If two-dimensional alignment test is used, then alignment correction can be determined, but the three-dimensional melt pool alignment cannot be accurately assessed
Solution Approach 1:
The patent creates a copy of the actual manufacturing process by forming test melt pools using full operational power. This copy reproduces the three-dimensional conditions of real object fabrication, allowing accurate assessment of laser alignment as it would occur during actual manufacturing, rather than relying on simplified two-dimensional proxies.
3Manufacturing precision
If alignment correction randomization is applied, then misalignment can be masked, but the actual alignment problem is not corrected
Solution Approach 1:
The patent performs preliminary alignment testing and correction using full operational power before actual manufacturing. By conducting the alignment test at high power and determining the actual misalignment, the system can apply accurate alignment corrections in advance, eliminating the need for randomization masking during production and ensuring reliable, consistent results.
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 ensures precise alignment of lasers, resulting in a smooth outer surface by accurately determining and correcting misalignment, effectively addressing the limitations of conventional alignment techniques.
Implementation Method 1
The laser moves in the X-Y direction using scanning mirrors, and has an intensity sufficient to fully weld (melt) the metal powder to form a solid metal
Implementation Method 2
The laser moves in the X-Y direction using scanning mirrors
Data Source
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AI summary
Methods for aligning a pair of calibrated lasers (134, 136) of a laser additive manufacturing system (100) in an overlap region (182) in which the pair of calibrated lasers (134, 136) selectively operate are provided. Respective first and second plurality of layers (190) of a test structure (180) are formed in the overlap region (182) of the pair of calibrated lasers (134, 136) solely using a first calibrated laser (134) of the pair of calibrated lasers (134, 136) and then solely using a second calibrated laser (136) of the pair of calibrated lasers (134, 136). The test structure (180) forming creates an outer surface of the test structure (180) corresponding to the overlap region (182). A dimension of an offset step (200, 202) created between the first plurality (184) of layers and the second plurality of lasers (190) in the outer surface of the test structure (180) is/are measured. The lasers (138') are aligned by applying the dimensions of the offset step (200, 202) as an alignment correction (111) to at least one of the pair of calibrated lasers (134, 136).