Eventos Anais de eventos
COBEF 2017
Congresso Brasileiro de Engenharia de Fabricação
Indirect selective laser sintering of gas and water atomized Stainless Steel (SS) powders
Submission Author:
Matheus Aguiar , SC , Brazil
Co-Authors:
José Maria Mascheroni, Cristiano Binder
Presenter: José Maria Mascheroni
doi://10.26678/ABCM.COBEF2017.COF2017-0355
Abstract
Indirect Selective laser sintering (SLS) of metals is an alternative process to produce free form parts against direct Selective laser melting (SLM) process. In an indirect method of SLS process, “green parts” can be formed through selectively fusing a polymer binder to bond metal particles with a low power CO2 laser. The polymer binder is subsequently removed and the polymer-free part (“brown part”) is then sintered or further processed to form a finished part. Stainless steel (SS) powders are widely used in powder metallurgy industry and are produced by two common techniques: gas atomization and water atomization. Gas atomization yields spherical particles and water atomization gives irregular particles. The density of the powder bed depends on particle packing density which is influenced by particle characteristics, such as size and shape. Selection of suitable power is a promising strategy to increase the sintered density without sacrificing any benefits of free form fabrication. In the present work, a Brazilian designed and manufactured SLS equipment, with a CO2 laser, were employed for study the densification of indirect selective laser sintered metal parts, fabricated by a mixture of Nylon-12 matrix and SS gas and water atomized powder, mechanically mixed. The aim is to understand the effects of the particle size and morphology on part densification and mechanical properties. The powder characteristics are examined by scanning electron microscope (SEM) and laser diffraction particle size analysis. After sintering in a plasma reactor, the pores sizes and porosity percent of both mixtures were evaluated. Further investigations are planned into post-processing, such as binder decomposition and high-temperature sintering, of the green parts made from the powders mixture.
Keywords
Selective laser sintering, indirect, Stainless Steel
