Spray Nozzle Array for Uniform Laser Cladding
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Solution Overview
Problem
Conventional laser cladding techniques face challenges in depositing wide coating layers with uniform thickness, as the Gaussian distribution of the laser beam leads to excessive vaporization, substrate disruption, and uneven surfaces, especially when overlapping clads, resulting in cavities and undesirable material properties.
Innovation Solution
A spray nozzle with an array of nozzle apertures arranged side-by-side, a powder supply chamber, and elongate gas apertures to eject a wide powder sheet and gas stream, allowing for uniform coating deposition by regulating powder flow and using guide plates to maintain a flat, even layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the laser beam diameter is increased to deposit a wider coating, then the coating width is improved, but the temperature at the centre of the melt pool causes excessive vaporisation of additive material and excessive melting of the substrate
Solution Approach 1:
The single laser beam is divided into multiple smaller laser beams arranged in an array pattern. This segmentation allows each beam to operate at optimal power density, preventing excessive vaporisation and substrate disruption while collectively covering a wider area to achieve broader coating deposition.
Solution Approach 2:
The invention transitions from a single-point laser beam to a multi-beam array configuration, effectively adding spatial distribution as a new dimension. This dimensional change enables simultaneous coverage of a wider area while maintaining controlled energy density at each beam location.
2Area of stationary object
If a number of clads are overlapped side-by-side to deposit a wide coating, then the coating width is improved, but cavities form between adjacent clads and the surface becomes uneven
Solution Approach 1:
The coating deposition process is segmented into multiple simultaneous laser beams rather than sequential single-beam passes. This segmentation with parallel processing eliminates the need for overlapping clads, preventing cavity formation and surface unevenness while achieving wide coating coverage.
Solution Approach 2:
Multiple laser beams operate simultaneously and continuously across the target area, creating a continuous deposition process. This eliminates the discontinuities and gaps that occur with sequential single-beam cladding, ensuring uniform surface quality without cavities between adjacent clads.
3Area of stationary object
If the laser beam diameter is increased, then the coating width is improved, but the substrate material is disrupted to an excessive depth and the deposited coating dilutes into the substrate
Solution Approach 1:
The laser energy is segmented into multiple beams with controlled individual power densities. This segmentation prevents excessive energy concentration that would cause deep substrate disruption and coating dilution, while the collective beam array achieves the desired wide coating width with uniform thickness.
Solution Approach 2:
The invention changes the parameter distribution by using multiple beams with optimized individual power levels rather than one high-power beam. This parameter adjustment maintains precise control over penetration depth and melting characteristics, preventing substrate disruption and coating dilution while achieving wide coverage.
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
The solution enables the deposition of wide coating layers with substantially uniform thickness, improving mechanical properties and reducing material usage by preventing overlap and surface irregularities, while minimizing thermal disruption and enhancing powder catchment efficiency.
Implementation Method 1
a powder supply chamber in fluid communication with the nozzle apertures and arranged in use to supply powder to the nozzle apertures under pressure so as to cause a wide powder sheet to be ejected from the array of nozzle apertures
Implementation Method 2
upper and lower elongate gas apertures located above and below the array of nozzle apertures respectively that extend substantially parallel to the array of nozzle apertures, wherein the upper and lower elongate apertures are arranged to eject a wide gas stream above and below the wide powder sheet
Data Source
AI summary
A spray nozzle 10 for a laser deposition apparatus comprises an array of nozzle apertures 16 arranged side-by-side, and a powder supply chamber 18 in fluid communication with the nozzle apertures 16. In use the powder supply chamber 18 supplies powder to the nozzle apertures 16 under pressure so as to cause a wide powder stream to be discharged from the array of nozzle apertures 16. When used with a laser deposition apparatus 100, a relatively wide coating of a uniform thickness can be deposited.