Plasma Torch Atomization of Wire Feedstock for Spherical Powder
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Solution Overview
Problem
Existing techniques for producing high-quality, dense spherical powders for additive manufacturing are inefficient, require complex alignment of plasma torches, and are limited to specific materials, leading to material contamination and high energy loss.
Innovation Solution
A plasma atomization process and apparatus that uses an inductively coupled plasma torch to atomize an elongated feed material, controlling preheating and exposure to plasma jets to produce spherical powder particles efficiently and economically, suitable for a broad range of materials including metals, ceramics, and composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple plasma torches are used to produce converging plasma jets, then the atomization capability is improved, but the alignment complexity and operational difficulty increase
Solution Approach 1:
The single plasma torch is segmented into multiple independent plasma jets through radial apertures in the nozzle. Each plasma jet can be independently controlled and positioned, eliminating the need for complex alignment of multiple torches while maintaining the converging jet configuration for effective atomization.
Solution Approach 2:
The nozzle structure serves as an intermediary component that transforms a single plasma source into multiple directed plasma jets. The radial apertures in the nozzle act as mediators to distribute and orient the plasma flow, simplifying the overall system configuration while achieving the desired atomization effect.
2Length of moving object
If plasma jets are generated at a distance from the apex, then the torch size is reduced, but thermal and kinetic energy are lost before reaching the material
Solution Approach 1:
The plasma jets are generated and directed toward the apex position in advance, with the nozzle structure pre-configured to channel the plasma flow. This preliminary positioning ensures that the plasma jets reach the material at the apex with maximum energy, eliminating energy loss while maintaining compact torch dimensions.
Solution Approach 2:
The plasma generation is transitioned from a single-point approach to a distributed radial arrangement around the apex. By utilizing the radial dimension, the plasma jets converge on the apex from multiple directions, reducing the required torch length while maintaining energy intensity at the material interaction point.
3Ease of manufacture
If conventional melt atomization techniques are used, then the production process is simple, but material contamination occurs
Solution Approach 1:
The conventional mechanical melt atomization process using crucibles is replaced with a plasma-based thermal field system. The plasma torch and nozzle configuration eliminates the need for physical contact with crucible walls, thereby preventing material contamination while maintaining process simplicity through the use of gas-phase plasma energy transfer.
Solution Approach 2:
The plasma environment provides an inert atmosphere that prevents oxidation and contamination of the material during atomization. The controlled plasma gas environment acts as a protective medium, allowing the material to be atomized without contact with contaminating surfaces or atmospheric gases.
4Object-affected harmful factors
If direct induction heating is used to melt wire or rod, then crucible contact is avoided, but the process is limited to pure metals or alloys
Solution Approach 1:
The plasma torch parameters including power, gas flow rate, and nozzle configuration are optimized to handle different material types. By adjusting these parameters, the system can effectively atomize pure metals, alloys, and ceramics, expanding material versatility while maintaining the benefit of crucible-free processing.
Solution Approach 2:
The plasma atomization system is designed with universal applicability through its ability to process multiple material types. The plasma environment and nozzle configuration can be adapted to handle diverse materials including metals, alloys, and ceramics, making the system multi-functional and broadly versatile.
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 process achieves high-quality, dense spherical powder particles with controlled particle sizes and minimal contamination, suitable for industrial-scale production of pure metals, alloys, and ceramics, with reduced energy loss and operational complexity.
Implementation Method 1
a plasma torch (120) producing plasma jets (180)
Implementation Method 2
inductively coupled plasma torch to atomize an elongated feed material
Implementation Method 3
the melt droplets are stripped and atomized by the plasma jets (180) into fine spherical particles
Implementation Method 4
the atomized droplets are frozen in-flight within a cooling chamber (170)
Data Source
Figure 1
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Figure 2b
AI summary
The present disclosure relates to a process and an apparatus for producing powder particles by atomization of a feed material in the form of an elongated member such as a wire, a rod or a filled tube. The feed material is introduced in a plasma torch. A forward portion of the feed material is moved from the plasma torch into an atomization nozzle of the plasma torch. A forward end of the feed material is surface melted by exposure to one or more plasma jets formed in the atomization nozzle. The one or more plasma jets being includes an annular plasma jet, a plurality of converging plasma jets, or a combination of an annular plasma jet with a plurality of converging plasma jets. Powder particles obtained using the process and apparatus are also described.