Laser Polarization Control in Powder Bed Fusion for Stable Cu Melting
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Solution Overview
Problem
Existing methods for producing three-dimensional work pieces using powder bed fusion struggle with inefficiencies and quality issues due to uncontrolled laser energy absorption and capillary formation during the additive layering process.
Innovation Solution
The method involves using linearly polarized laser radiation with a degree of polarization (DOP) between 30% and 99% to control the orientation of the plane of polarization relative to the plane of incidence, optimizing laser energy absorption and capillary stability, and adjusting parameters like scan direction and gas flow to enhance process stability and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If linearly polarized laser radiation with high degree of polarization (DOP ≥ 99%) is used, then laser energy absorption is enhanced, but capillary instability and material splashes increase
Solution Approach 1:
The patent changes the polarization parameter by using linearly polarized laser radiation with a controlled degree of polarization (DOP) between 30% and 99%, optimizing the balance between energy absorption and capillary stability. This parameter optimization resolves the contradiction by preventing excessive polarization that would cause capillary instability while maintaining sufficient energy absorption.
2Use of energy by moving object
If the plane of polarization is not aligned with the plane of incidence, then laser energy absorption decreases, but process stability is compromised
Solution Approach 1:
The patent implements dynamic control of the plane of polarization orientation relative to the plane of incidence. The system adaptively adjusts the polarization orientation during the additive manufacturing process to maintain optimal alignment, thereby simultaneously maximizing laser energy absorption and ensuring process stability through real-time parameter adjustment.
3Device complexity
If conventional unpolarized or randomly polarized laser radiation is used, then equipment complexity is reduced, but productivity and work piece quality decrease
Solution Approach 1:
The patent introduces controlled linear polarization as a parameter change in the laser radiation, which enhances productivity and work piece quality. By optimizing the degree of polarization and plane orientation, the system achieves improved manufacturing efficiency and quality without requiring excessively complex equipment modifications.
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 leads to improved process stability, increased productivity, and the production of high-quality three-dimensional work pieces, particularly with materials like Cu and Cu alloys, by enhancing laser energy absorption and reducing material splashes.
Implementation Method 1
the absorption of laser radiation impinging onto the raw material powder causes the raw material powder to melt and/or sinter
Implementation Method 2
irradiating layers of a raw material powder with laser radiation
Implementation Method 3
the evaporation of raw material leads to the formation of a vapor capillary via which the laser beam penetrates into deeper regions of the raw material
Implementation Method 4
a polarization means which performs a linear polarization of the laser beam is provided upstream of the spatial light modulator
Data Source
AI summary
In a method of operating an irradiation system (10) for irradiating layers of a raw material powder with laser radiation in order to produce a three-dimensional work piece (110) at least a section of a raw material powder layer (11) applied onto a carrier (102) is selectively irradiated with linearly polarized laser radiation having a degree of polarisation, DOP, of no more than 99% and no less than 30%. An orientation of a plane of polarization of the linearly polarized laser radiation is controlled in dependence on an orientation of a plane of incidence of the linearly polarized laser radiation on the raw material.