Polystyrene‐coated alumina powder via dispersion polymerization for indirect selective laser sintering applications

Abstract

A promising method for the manufacture of complex 3D ceramic parts is selective laser sintering (SLS). SLS of alumina components can be done either directly or indirectly. In this article, the indirect method is used by using polystyrene coated alumina particles. One of the methods to produce these alumina powders is dispersion polymerization. In this research, it is described how the alumina powder has been developed and tested. The powder has been characterized to define its processability within the SLS process. Used techniques include SEM (morphology), STA/TGA (overall mass loss), DSC (glass transition temperature T g ), and laser diffraction (particle size distribution). The investigated SLS process parameters were the preheating temperature, laser power, scan spacing, and scan speed. STA/TGA has proven that polystyrene-coated alumina powders are suitable for SLS process, while DSC results were judged to be a good source of complementary data on preheating temperature of alumina/polystyrene powders. SLS experiments showed that single layer green parts can be produced. By using the optimized SLS parameters, it was demonstrated that different 3D geometries can be produced with the polystyrene coated alumina powders.

Shaping ceramics through indirect selective laser sintering

“…As the SLS machine was equipped with a counter current roller for the deposition of dry powders, different powders had to be developed. Five different Al 2 O 3 containing composite powders were produced by four powder production methods (Table I): ball milling (Deckers et al , 2012b), dispersion polymerization – cake formation – ball milling (Deckers et al , 2013, Cardon et al , 2013), thermally induced phase separation (TIPS 1) (Deckers et al , 2012a, Shahzad et al , 2012, 2013) and thermally induced phase separation – cake formation – ball milling (TIPS 2) (Rombouts et al , 2012). The five composite powders had different binder materials and a different amount of binder: polyamide (PA, 53 vol%) (Deckers et al , 2012b) (and 60 vol%) (Shahzad et al , 2012, Deckers et al , 2012a), amorphous polystyrene (PS, 71 vol%) (Cardon et al , 2013, Deckers et al , 2013), polypropylene (PP, 60 vol%) (Shahzad et al , 2013) and a 82 wt% carnauba wax–18 wt% low-density polyethylene combination (carn.…”

“…Five different alumina containing composite powders were produced by four powder production methods (Table 1): ball milling (Deckers et al, 2012b), dispersion polymerization -cake formation -ball milling (Deckers et al, 2013, thermally induced phase separation (TIPS1 (Deckers et al, 2012a, Shahzad et al, 2012) and thermally induced phase separationcake formation -ball milling (TIPS2) (Rombouts et al, 2012). The five composite powders had different binder materials and a different amount of binder: polyamide (PA, 53vol% (Deckers et al, 2012b) and 60vol% (Shahzad et al, 2012, Deckers et al, 2012a), amorphous polystyrene (PS, 71vol%) (Cardon et al, 2013, polypropylene (PP, 60vol%) (Shahzad et al, 2013) and a 82 wt% carnauba wax -18 wt% low density polyethylene combination (carn.+LDPE, 54vol% (Rombouts et al, 2012)). PA and PP were chosen as binder material since they have an 'SLS window' (Drummer et al, 2010) due to their semi-crystalline behavior (PP has an SLS window at a lower temperature compared to PA).…”

Densification and Geometrical Assessments of Alumina Parts Produced Through Indirect Selective Laser Sintering of Alumina-Polystyrene Composite Powder

“…After being dried, the cake material prepared in the 2000 ml flask was ground in a ball mill (Fritsch, Germany) to obtain a fine powder that was sieved (Retsch, Germany) with a mesh of 160 µm. For a more detailed description of the powder production method, see Cardon et al [37].…”

The synthesis of epoxy resin coated Al2O3composites for selective laser sintering 3D printing

“…Nelson et al (1995) synthesized the poly (methyl methacrylate) (PMMA)-coated silicon carbide powders for SLS. Also, a systematical study on polymer-coated alumina powder's influence on the 3D printing parts' density and mechanical properties is done by Tang et al (2011) and Cardon et al (2013). Liu et al (2016) brought up a novel approach to fabricate complex tradition ceramic products via SLS combined with CIP and sintering.…”