Ring-Shaped Laser Deposition Head for Precise Powder Delivery
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Solution Overview
Problem
The directed energy deposition method in additive manufacturing faces challenges with low material powder usage efficiency due to complex parameter combinations, leading to powder scattering and difficulty in achieving a 100% usage rate, which results in increased costs and maintenance issues.
Innovation Solution
An additive-manufacturing head with a ring-shape laser beam forming unit using axicon lenses and a convex lens, along with moving mechanisms to control the laser-beam-irradiated region, allows for precise adjustment of the laser beam size and powder feeding to optimize powder deposition efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If material powder is fed from outside the laser beam, then the directed energy deposition method can be implemented, but it is difficult to prevent scattering of the material powder to the outside of the melt pool, resulting in low material powder usage efficiency
Solution Approach 1:
A gas flow field is introduced as an intermediary between the material powder feed and the laser beam. The gas flow acts as a mediator to transport material powder from outside the laser beam into the laser beam path, enabling controlled delivery of powder to the melt pool while preventing scattering to the outside environment.
Solution Approach 2:
The problem is solved by transitioning from a two-dimensional view (powder fed directly to laser beam) to a three-dimensional approach. Material powder is fed from outside the laser beam through a gas flow field that extends in the depth direction, allowing powder to be delivered to the laser beam path without direct contact between the feed mechanism and the laser beam path.
2Loss of substance
If the combination of laser output, material powder feed amount, carrier gas feed amount, and feed rate is optimized, then material powder usage efficiency can be improved, but the parameter combination is complicated making optimization difficult
Solution Approach 1:
The complex parameter optimization problem is extracted and separated into independent controllable factors. The gas flow field parameters (flow rate, direction, velocity distribution) are extracted as independent control variables, allowing optimization of material powder delivery efficiency without needing to simultaneously optimize all four parameters (laser output, powder feed amount, carrier gas feed amount, and feed rate) together.
Solution Approach 2:
The invention changes the control parameters from the traditional four-parameter combination to gas flow field parameters (flow rate, direction, velocity profile). By changing the parameter space and introducing gas flow characteristics as the primary control variables, the optimization becomes more manageable and directly controllable.
3Loss of substance
If material powder is collected in the machining chamber, then material powder usage efficiency can be improved, but a device is necessary for collecting material powder and uncollected powder must be discarded, increasing cost and maintenance difficulty
Solution Approach 1:
The gas flow field, which could potentially cause powder scattering, is converted into a beneficial tool for powder control. The same gas flow that transports powder is used to contain and direct powder precisely to the melt pool, turning a potential harmful effect (scattering) into a useful function (precise delivery and containment).
Solution Approach 2:
The gas flow field performs multiple functions simultaneously: it transports material powder, contains the powder within the laser beam path, directs powder to the melt pool, and protects surrounding areas from powder scattering. This self-service approach eliminates the need for separate collection devices while improving powder usage efficiency.
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 solution enables efficient control of the laser-beam-irradiated region and material powder distribution, enhancing deposition accuracy and reducing waste, thus improving overall manufacturing efficiency and reducing maintenance needs.
Implementation Method 1
a ring-shape laser beam forming unit including a first axicon lens and a second axicon lens disposed to face each other in an optical axis direction of the laser beam, and a convex lens disposed between the first axicon lens and the second axicon lens, to form the laser beam entering through the first axicon lens into a ring-shape laser beam
Implementation Method 2
irradiating the workpiece with a laser beam
Implementation Method 3
the workpiece is irradiated with a laser beam
Implementation Method 4
material powder is fed from an additive-manufacturing head to a workpiece
Data Source
AI summary
An additive-manufacturing head includes: a ring-shape laser beam forming unit having axicon lenses facing each other and a convex lens between the axicon lenses to form a laser beam entering through the axicon lens into a ring-shape laser beam and emit the ring-shape laser beam from the other axicon lens; a lens moving mechanism to move the convex lens in the optical axis direction of the laser beam; a laser beam emitting unit to emit the ring-shape laser beam toward a workpiece; and a material powder feeding tube having an outlet which is disposed inside the ring-shape laser beam emitted from the laser beam emitting unit and from which material powder is released, to feed the material powder from the outlet toward the workpiece. Accordingly, the additive-manufacturing head capable of freely controlling the size of the laser-beam-irradiated region and the laser beam intensity distribution on the workpiece is provided.