scholarly journals Development of a characterization approach for the sintering behavior of new thermoplastics for selective laser sintering

2010 ◽  
Vol 5 ◽  
pp. 533-542 ◽  
Author(s):  
Dietmar Drummer ◽  
Dominik Rietzel ◽  
Florian Kühnlein
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Sintering Behavior

PREPARATION OF Cu-SiO2/PA12 COMPOSITE POWDERS BY ELECTROLESS PLATING FOR USE IN SLS PROCESSING

2019 ◽  
Vol 26 (09) ◽  
pp. 1950055
Author(s):  
CHENGMEI GUI ◽  
ZHENMING CHEN ◽  
CHENGUANG YAO ◽  
GUISHENG YANG
Keyword(s):  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Composite Particles ◽  
Sintering Behavior ◽  
Contact Interface ◽  
Composite Powders ◽  
Copper Particles ◽  
Dimensional Precision ◽  
Composite Plating ◽  
Sintering Neck

In this work, SiO2-encapsulated copper particles/PA12 (Cu-SiO2/PA12) composite powders were prepared by electroless composite plating, and the laser sintering behavior was investigated. Results showed that Cu, Cu2O, CuO, and SiO2 (Cu-SiO2) composite particles were plated on the surface of KH550-modified PA12 powders. The Cu-SiO2 particles existed independently on PA12 surface, and the size was around 200 nm. The melting temperature and crystallization temperature of Cu-SiO2/PA12 composite powders were 183∘C and 150∘C. The results indicate that the selective laser sintering (SLS) process involved the contact of Cu-SiO2/PA12 powders, the formation of sintering neck, the growth of sintering neck, and the formation of fused solid. The Cu-SiO2 composite particles uniformly dispersed in the part due to surface tension, and the contact interface was good due to their similar polarity. The Cu-SiO2/PA12 SLS parts had excellent dimensional precision. The tensile strength of the 15[Formula: see text]W-sintered Cu-SiO2/PA12 specimen was 48[Formula: see text]MPa.

Processing and Characterization of Core-Shell PA12/Silica Composites Produced by Selective Laser Sintering

2010 ◽  
Vol 160-162 ◽  
pp. 756-761 ◽  
Author(s):  
Jian Hong Wang ◽  
Pei Kang Bai ◽  
Zhen Lin Zhang ◽  
Yu Xin Li
Keyword(s):  
Emulsion Polymerization ◽  
Silica Particle ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Silica Particles ◽  
Sintering Behavior ◽  
Core Shell ◽  
Dense Structure ◽  
Maximum Value

Silica particles coated with PA12 by emulsion polymerization were used as fillers to reinforce PA12 based composites prepared by selective laser sintering (SLS). The influences of the treated and untreated particles on the sintering behavior and mechanical properties of the laser sintered specimens were investigated. It was found that there were many uneven holes in the untreated composites. However, for the treated composites, due to the silica particle surfaces treated by emulsion polymerization, the absorbance of laser was improved and the particles dispersed well in the polymer matrix; a full dense structure was obtained and the properties were enhanced, such as the tend strength increased 30%, the maximum value was 34MPa; the tensile strength increased up to 125%, the maximum value was 44.2 MPa, comparing to the unfilled PA12. Drawing from the results, it can be confirmed that a full dense structure can be obtained and the PA12 matrix was strengthened and toughened when the silica particles were coated with PA12 by emulsion polymerization.

scholarly journals Production and Processing of a Spherical Polybutylene Terephthalate Powder for Laser Sintering

2019 ◽  
Vol 9 (7) ◽  
pp. 1308 ◽  
Author(s):  
Rob Kleijnen ◽  
Manfred Schmid ◽  
Konrad Wegener
Keyword(s):  
Mechanical Properties ◽  
Thermal Processing ◽  
Selective Laser Sintering ◽  
Spherical Shape ◽  
Laser Sintering ◽  
Polybutylene Terephthalate ◽  
Powder Production ◽  
Injection Molded ◽  
Continuous Extrusion ◽  
Matrix Powder

This work describes the production of a spherical polybutylene terephthalate (PBT) powder and its processing with selective laser sintering (SLS). The powder was produced via melt emulsification, a continuous extrusion-based process. PBT was melt blended with polyethylene glycol (PEG), creating an emulsion of spherical PBT droplets in a PEG matrix. Powder could be extracted after dissolving the PEG matrix phase in water. The extrusion settings were adjusted to optimize the size and yield of PBT particles. After classification, 79 vol. % of particles fell within a range of 10–100 µm. Owing to its spherical shape, the powder exhibited excellent flowability and packing properties. After powder production, the width of the thermal processing (sintering) window was reduced by 7.6 °C. Processing of the powder on a laser sintering machine was only possible with difficulties. The parts exhibited mechanical properties inferior to injection-molded specimens. The main reason lied in the PBT being prone to thermal degradation and hydrolysis during the powder production process. Melt emulsification in general is a process well suited to produce a large variety of SLS powders with exceptional flowability.

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