The selective laser sintering (SLS) is an additive manufacturing technique, which allows the construction of three-dimensional objects layer by layer with even very complex geometry. It is based on the possibility of sintering with a laser beam selectively particles arranged on a floor layer. Layer by layer is possible produce solid forms of even very complex geometry. The granular material used in this process must have well-defined characteristics, in particular, must be capable of forming a thin and homogeneous layer of about 100 microns. The main factors which determine the ability of the particles used to form relatively homogeneous layers are: the average diameter, the shape and the interparticle forces [1], which directly or indirectly define the flow properties of the powder used to form the layers. The quality of the spread powder layer in each cycle depends on the procedure followed and the numerous techniques used to measure the powder flowability adopt measuring conditions which are very different from those occurring during the layer formation in LS [2-3]. This paper proposes a characterization technique of powder quality for SLS application by using a set up that mimics the movements in an SLS apparatus (Figure1). A roller is used to spread the powder. It works by advancing against a pile of the powder. The set up allows to independently control and the advancement and rotation speed. The quality of the produced powder layer is characterized by means of a linear laser beam scanning its surface. In particular, the image of the laser beam projected on the surface is analyzed in order to obtain a quality index indicating the homogeneity of the powder formed layers. The values of this quality index are compared to the flow properties of the material measured with standard technologies.

Flowability of ceramic powders in the sintering process

SOFIA, DANIELE;BARLETTA, Diego;POLETTO, Massimo
2016-01-01

Abstract

The selective laser sintering (SLS) is an additive manufacturing technique, which allows the construction of three-dimensional objects layer by layer with even very complex geometry. It is based on the possibility of sintering with a laser beam selectively particles arranged on a floor layer. Layer by layer is possible produce solid forms of even very complex geometry. The granular material used in this process must have well-defined characteristics, in particular, must be capable of forming a thin and homogeneous layer of about 100 microns. The main factors which determine the ability of the particles used to form relatively homogeneous layers are: the average diameter, the shape and the interparticle forces [1], which directly or indirectly define the flow properties of the powder used to form the layers. The quality of the spread powder layer in each cycle depends on the procedure followed and the numerous techniques used to measure the powder flowability adopt measuring conditions which are very different from those occurring during the layer formation in LS [2-3]. This paper proposes a characterization technique of powder quality for SLS application by using a set up that mimics the movements in an SLS apparatus (Figure1). A roller is used to spread the powder. It works by advancing against a pile of the powder. The set up allows to independently control and the advancement and rotation speed. The quality of the produced powder layer is characterized by means of a linear laser beam scanning its surface. In particular, the image of the laser beam projected on the surface is analyzed in order to obtain a quality index indicating the homogeneity of the powder formed layers. The values of this quality index are compared to the flow properties of the material measured with standard technologies.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11386/4687239
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact