Coaxial LMD Head Layout for Tight-Space Powder Deposition
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Solution Overview
Problem
Conventional laser metal deposition (LMD) head designs are difficult to maintain, inefficient in powder delivery, too large to access tight spaces, prone to laser reflections, and lack customization options for auxiliary gas flows, leading to precision issues and material waste.
Innovation Solution
The improved LMD head design features angled powder inlets and outlets, helical powder channels for even distribution, angled powder distribution channels to reduce nozzle wear, a clamping mechanism for easy maintenance, adjustable axial hard-stop for precise focus, external cooling elements, and modular auxiliary gas nozzles for customizable gas flows, all within a compact and robust construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LMD head designs are used with protruding hoses for powder, gas, and coolant delivery, then the head can deliver all necessary functions, but the diameter becomes greater than 100 mm which limits access to tight spaces and reduces manufacturing precision
Solution Approach 1:
The patent applies nesting by placing the coolant delivery line, powder delivery line, and gas delivery line concentrically within each other, with the coolant line at the center, powder line surrounding it, and gas line outermost. This nested arrangement reduces the overall diameter of the LMD head to enable access to tight spaces while maintaining all necessary delivery functions.
2Reliability
If conventional LMD head designs with protruding hoses are used, then all delivery functions are achieved, but the head becomes susceptible to laser reflections which may damage the powder, gas, coolant delivery lines and other parts
Solution Approach 1:
The nested concentric arrangement of delivery lines within the LMD head body positions all hoses internally rather than protruding externally. This configuration shields the powder, gas, and coolant delivery lines from direct exposure to laser reflections, thereby protecting them from damage and improving system reliability.
3Productivity
If conventional LMD heads with independent powder-stream nozzles are used, then multiple powder streams can be delivered, but the powder cannot be focused into the laser spot as precisely as with coaxial nozzles, resulting in delivery rates less than 50% and wasted material
Solution Approach 1:
The patent merges multiple powder streams into a single coaxial arrangement where powder is delivered through a central nozzle aligned with the laser beam axis. This consolidation focuses all powder delivery into the laser spot precisely, achieving delivery rates above 50% and eliminating the material waste associated with multiple independent nozzles.
4Ease of repair
If conventional LMD heads are used, then basic powder delivery is achieved, but maintenance is difficult and requires time-intensive disassembly to clean powder and change nozzles
Solution Approach 1:
The LMD head is segmented into modular components including the nozzle assembly, delivery lines, and cooling system that can be independently accessed and maintained. The nozzle can be quickly removed and replaced by accessing it from the front of the head, while the concentric delivery lines can be cleaned by introducing solvents through the central coolant channel, significantly reducing maintenance time and effort.
5Adaptability or versatility
If conventional LMD heads are used, then basic shield gas flow is provided, but customization of auxiliary shield gas flows is not allowed
Solution Approach 1:
The LMD head incorporates multiple gas delivery channels including shield gas, auxiliary shield gas, and cooling gas channels that can all be configured through the same concentric structure. The auxiliary gas channel surrounds the shield gas channel, allowing independent control and customization of different gas flows for various processing requirements, making the head versatile for different applications.
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 design enhances precision, reduces material waste, minimizes laser reflections, allows for easier maintenance and nozzle changes, and provides customizable gas flows, resulting in improved deposition quality and versatility in tight spaces.
Implementation Method 1
a coolant sleeve comprising an inner surface in contact with an outer surface of the outer nozzle
Implementation Method 2
a laser generates a molten bath on an existing surface
Implementation Method 3
The powder melts and bonds with the base material in the molten pool thereby forming new layers
Data Source
AI summary
Aspects of the present disclosure relate to improved laser metal deposition heads. Various embodiments may include a main body, a nozzle seat, a powder flow guide, an inner nozzle, an outer nozzle, and a coolant sleeve. In some embodiments, powder inlets in the main body are angled relative to a primary axis of the laser metal deposition head. In some embodiments, the nozzle seat includes a plurality of powder distribution channels that are also angled relative to the primary axis of the laser metal deposition head.