Laser Beam Oscillation in Metal DED for Trace Width Control
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Solution Overview
Problem
Directed energy deposition additive manufacturing systems face challenges in achieving high productivity while maintaining precision and quality, often requiring complex systems and increased production times due to the need for multiple heads or adaptive collimators that cannot vary energy distribution.
Innovation Solution
A method and system that impart a dynamic movement on the laser beam during additive manufacturing, allowing the width of the metal trace to be independent of the laser spot size, with a power distribution varying along the trace width, enabling decoupling of trace depth and width, and using cyclic movements like oscillations to control the trace geometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a laser beam with a fixed focusing spot size is used for directed energy deposition, then the trace width is determined by the spot size, but the productivity is limited because the system cannot rapidly change trace geometry
Solution Approach 1:
The patent applies dynamics by making the laser beam movable relative to the powder jet through rapid oscillation of optical deflectors (galvanometric mirrors or acousto-optic deflectors). This allows the laser spot to dynamically scan across the powder deposition area, enabling the trace width to be varied by changing the oscillation amplitude or pattern without physical reconfiguration of the system. The dynamic control of laser position decouples trace geometry from fixed optical parameters, thereby increasing productivity while maintaining relatively simple system architecture.
2Manufacturing precision
If multiple additive manufacturing heads are used to achieve different trace characteristics, then manufacturing precision is improved, but device complexity and production time increase
Solution Approach 1:
The patent implements multi-functionality by enabling a single additive manufacturing head to produce multiple trace geometries and characteristics through dynamic laser beam oscillation. By controlling the oscillation parameters (amplitude, frequency, pattern), the same head can generate narrow or wide traces, shallow or deep melt pools, and various trace profiles. This universal capability eliminates the need for multiple specialized heads while maintaining manufacturing precision across different trace requirements.
Solution Approach 2:
The patent applies parameter changes by varying the laser beam oscillation parameters (amplitude, frequency, waveform) to achieve different trace characteristics. Changing the oscillation amplitude modifies the effective laser spot width, while changing the oscillation pattern (e.g., sinusoidal, triangular, custom waveforms) controls the power distribution across the trace. This parametric control allows a single head to adapt to different manufacturing requirements, achieving high precision without increasing the number of heads.
3Productivity
If the laser spot size is increased to widen the trace, then productivity is improved, but the resolution and surface quality deteriorate
Solution Approach 1:
The patent applies segmentation by dividing the effective laser heating zone into multiple positions through oscillation. Instead of using a single large spot that would reduce resolution, the laser spot is rapidly moved across multiple positions, effectively segmenting the energy delivery. This creates a wider trace through sequential heating of adjacent areas while maintaining high resolution at each individual spot position, as each location receives focused energy from the smaller oscillating spot rather than diffuse energy from a large spot.
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 allows for high productivity with precise control over trace geometry, enabling faster production of complex parts with reduced porosity and increased resolution, simplifying system complexity and reducing production time.
Implementation Method 1
a laser-beam focusing and directing device for directing a laser beam onto such a region simultaneously with direction of such jets of metal powders, to form a focusing spot of the laser beam on such a region
Implementation Method 2
to give rise to a trace obtained by means of melting of such powders as a result of the power transmitted to such powders by such a focusing spot
Data Source
Figure 1A~1B
Figure 2
Figure 3~3A
AI summary
A method for additive manufacturing, wherein an additive-manufacturing head (12) is provided, configured both for directing one or more jets of powders, in particular metal powders, onto a region of a working surface (110), and for directing simultaneously a laser beam onto such a region, to form a laser-beam focusing spot (LS) on the region, and wherein, during direction of the powder jets and of the laser beam, the additive-manufacturing head (12) is simultaneously translated in a direction transverse to the direction of the laser beam so as to give rise to a trace (MRP) obtained by melting of the powders as a result of the power transmitted to the powders by the focusing spot (LS). During movement of the additive-manufacturing head (12) in the transverse direction, a dynamic movement is imparted on the laser beam emitted by the head (12), the movement being configured in such a way as to obtain a width of the trace (MRP) that is independent of the size of the focusing spot (LS) of the laser beam (L) and is equivalent to the one that would be produced by an apparent spot having a width substantially corresponding to the width of the trace (MPP), and in such a way that the distribution of the power transmitted by the laser beam to the trace (MPP) varies along the direction of the width of the trace (MPP).