Astigmatic Beam Shaping for Faster Welding Without Evaporation
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Solution Overview
Problem
In additive manufacturing and welding, increasing the power and speed of the energy beam beyond a certain point leads to evaporation of the material due to insufficient heat penetration, limiting the efficiency and speed of the process.
Innovation Solution
The use of an astigmatism lens to shape the energy beam, making it longer in the direction parallel to the deflection direction than perpendicular to it, allowing for higher power and faster scan speeds while maintaining sufficient heat penetration and avoiding evaporation, by varying the beam spot size based on power and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power of the energy beam is increased beyond a predetermined value, then the efficiency and speed of welding or additive manufacturing is improved, but the material evaporates due to excessive surface temperature
Solution Approach 1:
The patent changes the physical parameters of the energy beam by introducing astigmatism, transforming the beam profile from circular to elliptical. This parameter change allows the beam to deliver higher power while distributing energy over a larger area, preventing excessive temperature rise and material evaporation.
Solution Approach 2:
The patent applies asymmetry by creating an elliptical beam spot through astigmatism lenses, where the beam has different dimensions in orthogonal directions. The major axis is oriented parallel to the scanning direction, creating an asymmetric energy distribution that enables higher power delivery without proportional temperature increase, thus avoiding evaporation while maintaining welding speed.
2Productivity
If the speed of deflection of the energy beam is increased, then the efficiency and speed of welding or additive manufacturing is improved, but the heat from the energy beam does not have sufficient time to penetrate into the material
Solution Approach 1:
The patent modifies the beam parameters by introducing controlled astigmatism, which changes the spatial distribution of energy. This parameter change allows the system to operate at higher deflection speeds while maintaining adequate heat penetration, as the elliptical profile distributes energy more effectively along the scanning direction.
Solution Approach 2:
The patent transitions from a one-dimensional circular beam spot to a two-dimensional elliptical beam spot by utilizing astigmatism. This dimensional change allows the beam to cover a larger area parallel to the scanning direction, compensating for the reduced interaction time at higher deflection speeds and ensuring sufficient heat penetration.
3Length of stationary object
If the power of the energy beam is increased, then the fusing depth is improved, but the surface temperature becomes too high causing material evaporation
Solution Approach 1:
The patent changes the beam profile parameter from circular to elliptical through astigmatism, allowing higher power to be delivered while the energy is distributed over a larger surface area. This parameter change enables deeper fusing without proportional surface temperature increase, preventing evaporation.
Solution Approach 2:
The asymmetric elliptical beam profile concentrates energy in the direction perpendicular to the scan (minor axis) to achieve deep penetration, while extending along the scan direction (major axis) to distribute heat over a larger area, preventing excessive surface temperature and evaporation.
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 method enables increased power and speed without material evaporation, maintaining fusing accuracy and reducing building time in additive manufacturing.
Implementation Method 1
shaping the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction
Implementation Method 2
focusing the high energy beam on said workpiece with at least one focusing lens
Implementation Method 3
deflecting the high energy beam with at least one deflection lens for making a second weld at a second position on said workpiece
Implementation Method 4
making a first weld at a first position on said workpiece with a high energy beam
Implementation Method 5
the heat from the energy beam will not have sufficient time to penetrate into the material to be fused or welded
Data Source
AI summary
Various embodiments of the present invention relate to a method for welding a workpiece comprising the steps of: making a first weld at a first position on said workpiece with a high energy beam, deflecting the high energy beam with at least one deflection lens for making a second weld at a second position on said workpiece, focusing the high energy beam on said workpiece with at least one focusing lens, shaping the high energy beam on said workpiece with at least one astigmatism lens so that the shape of the high energy beam on said workpiece is longer in a direction parallel to a deflection direction of said high energy beam than in a direction perpendicular to said deflection direction of said high energy beam. The invention is also related to the use of an astigmatism lens and to a method for forming a three dimensional article.