A novel convergent–divergent annular nozzle design for close-coupled atomisation. (27th May 2017)

• Record Type: Journal Article
• Authors: Schwenck, Daniel; Ellendt, Nils; Fischer-Bühner, Jörg; Hofmann, Peter; Uhlenwinkel, Volker
• Is Part Of: Powder metallurgy. Volume 60:Number 3(2017)
• Page Start: 198
• Page End: 207
• Publication Date: 2017-05-27
• Subjects: Atomisation -- melt -- close-coupled -- nozzle design -- CuSn -- powder -- convergent–divergent; Powder metallurgy -- Periodicals; 671.3705
• DOI: 10.1080/00325899.2017.1291098
• Languages: English
• ISSNs: 0032-5899

Abstract

ABSTRACT: Additive manufacturing processes such as selective laser melting and electron beam melting require small particle sizes. A widely used technique to produce suitable powders is close-coupled atomisation. To further decrease the achieved particle sizes, the annular geometry of the gas nozzle is changed to a convergent–divergent (CD) profile. This novel configuration is capable of operating stably at low pressures of 0.8 MPa and above. Beyond that, the unwanted effects of lick-back are avoided. Different nozzles with conventional and convergent–divergent annular geometry have been designed based on fluid-flow calculations. The aspiration pressure was measured to determine stable process windows. Powders from a CuSn alloy were produced using cold and hot gas atomisation to show the influence on the process stability, particle size and morphology. High-speed recordings are used to investigate the process conditions of the different nozzle configurations.