scholarly journals Improvement on Selective Laser Sintering and Post-Processing of Polystyrene

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 956 ◽  
Author(s):  
Zhi Zeng ◽  
Xiaohu Deng ◽  
Jiangmei Cui ◽  
Hai Jiang ◽  
Shuo Yan ◽  
...  

Amorphous polymers are heavily utilized materials in selective laser sintering (SLS) due to their good dimensional accuracy. However, sintered parts of amorphous polymers cannot be used as functional parts owing to their poor forming performance, including their low relative densities and tensile strength. Therefore, post-processing methods are employed to enhance the mechanical properties of amorphous polymers SLS parts without damaging their relatively high dimensional accuracy. In this study, the forming process of selective laser sintering (SLS) and post-processing on polystyrene (PS) was investigated. The orthogonal experiment was designed to obtain the optimal combination of process parameters. The effect of a single process parameter and the laser volumetric energy density (LVED) on dimension accuracy and warpage of the sintered parts were also discussed. In addition, a three-dimensional (3D) thermal model was developed to analyze the temperature fields of single-layer SLS parts and PS powder sintering mechanism. Then, infiltrating with epoxy resin was employed to enhance the mechanical properties of the PS parts. Good resin-infiltrated formulation was obtained based on the mechanical property tests and fractured surface analysis. This research provides guidance for SLS process and post-processing technology in polymers.

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3034
Author(s):  
Aboubaker I. B. Idriss ◽  
Jian Li ◽  
Yangwei Wang ◽  
Yanling Guo ◽  
Elkhawad A. Elfaki ◽  
...  

The range of selective laser sintering (SLS) materials is currently limited, and the available materials are often of high cost. Moreover, the mechanical strength of wood–plastic SLS parts is low, which restricts the application of a SLS technology. A new composite material has been proposed to address these issues, while simultaneously valorizing agricultural and forestry waste. This composite presents several advantages, including reduced pollution associated with waste disposal and reduced CO2 emission with the SLS process in addition to good mechanical strength. In this article, a novel and low-cost Prosopis chilensis/polyethersulfone composite (PCPC) was used as a primary material for SLS. The formability of PCPC with various raw material ratios was investigated via single-layer experiments, while the mechanical properties and dimensional accuracy of the parts produced using the various PCPC ratios were evaluated. Further, the microstructure and particle distribution in the PCPC pieces were examined using scanning electron microscopy. The result showed that the SLS part produced via 10/90 (wt/wt) PCPC exhibited the best mechanical strength and forming quality compared to other ratios and pure polyethersulfone (PES), where bending and tensile strengths of 10.78 and 4.94 MPa were measured. To improve the mechanical strength, post-processing infiltration was used and the PCPC-waxed parts were enhanced to 12.38 MPa and 5.73 MPa for bending and tensile strength.


2015 ◽  
Vol 30 (8) ◽  
pp. 1045-1055 ◽  
Author(s):  
Dejin Zhao ◽  
Yanling Guo ◽  
Kaiyi Jiang ◽  
Hui Zhang

A new type of biocomposite, bamboo flour/copolyester (BFCP) composite for selective laser sintering (SLS™) was studied in this article. The bamboo flour was made from the bamboo residual of the bamboo production collected from a chopsticks factory. The BFCP composites of three mixture ratios (20/80, 25/75, and 30/70 (wt/wt)) were processed by SLS™. The proper processing parameters were determined by single-layer sintering methods. The mechanical properties of test specimens made from BFCP composites of three mixture ratios have been investigated. The results demonstrated that the mechanical properties of the specimens made by BFCP composite of 20/80 (wt/wt) were the best among those of the three mixture ratios and the average tensile strength, flexural strength, and impact strength of the specimens made from BFCP composite of 20/80 (wt/wt) were up to 4.14 MPa, 11.02 MPa, and 0.84 kJ m−2, respectively. The mechanical properties of specimens are extremely improved through infiltrating epoxy resin.


BioResources ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 1338-1353
Author(s):  
Jian Li ◽  
Aboubaker I. B. Idriss ◽  
Yanling Guo ◽  
Yangwei Wang ◽  
Zhiqiang Zhang ◽  
...  

Selective Laser Sintering (SLS) technology can be utilized to recycle residues from forestry and agriculture, thereby alleviating shortages of materials and reducing energy consumption by producing wood-plastic pieces for industrial application. The mechanical strength of wood-plastic SLS parts is low, which restricts the application of this technology. In this study, a novel type of sisal fiber/poly-(ether sulfone) (PES) composite was prepared using a polymer mixing method in order to improve the mechanical properties of SLS parts. Single-layer sintering method was adopted to determine the proper processing parameters. The mechanical properties of the parts with different ingredient ratios and different particle sizes of sisal fiber before and after post-processing were tested using a universal testing machine. The morphology was examined using scanning electron microscopy (SEM). Results showed that the mechanical properties of the printed parts were relatively enhanced; when the mixing ratio of composite powder was 10/90 wt/wt. In addition, the part fabricated by powder of particles size less than 0.105 mm (0.125 mm ≥ PS < 0.105mm) had the best mechanical strength. Moreover, the post-wax treatment significantly improved the strength of the parts, and the surfaces became smoother.


2008 ◽  
Vol 594 ◽  
pp. 241-248 ◽  
Author(s):  
Fwu Hsing Liu ◽  
Yunn Shiuan Liao ◽  
Hsiu Ping Wang

The material in powder state has long been used by selective laser sintering (SLS) for making rapid prototyping (RP) parts. A new approach to fabricate smoother surface roughness RP parts of ceramic material from slurry-sate has been developed in this study. The silica slurry was successfully laser-gelling in a self-developed laser sintering equipment. In order to overcome the insufficient bonding strength between layers, a strategy is proposed to generate ceramic parts from a single line, a single layer, to multi-layers of gelled cramic in this paper. It is found that when the overlap of each single line is 25% and the over-gel between layers is 30%, stronger and more accurate dimensional parts can be obtained under a laser power of 15W, a laser scanning speed of 250 mm/s, and a layer thickness of 0.1 mm. The 55:45 wt. % of the proportion between the silica powder and silica solution results in suitable viscosity of the ceramic slurries without precipitation. Furthermore, the effects of process parameters for the dimensional accuracy and surface roughness of the gelled parts are investigated and appropriate parameters are obtained.


2010 ◽  
Vol 43 ◽  
pp. 430-433
Author(s):  
Nai Fei Ren ◽  
Pan Wang ◽  
Yan Luo ◽  
Hui Juan Wu

The dimensional accuracy and mechanics properties of parts made by Selective Laser Sintering depend greatly on the sintering process parameters. The influence of process parameters on warping weight of parts sintered by blends of polyamide (PA12) and high density polyethylene (HDPE) was studied. The relationship between the process parameters and the warping height was presented. The surface morphology of the part and uniformity of powder mixed were analyzed by SEM. The optimum parameters of minimum warping height were obtained: preheat temperature 110°C, scan speed 300mm/s, laser power 21W, thickness of single layer 0.2mm.


2014 ◽  
Vol 915-916 ◽  
pp. 1000-1004 ◽  
Author(s):  
Xiao Hui Song ◽  
Yu Sheng Shi ◽  
Ping Hui Song ◽  
Qing Song Wei ◽  
Wei Li

Selective Laser Sintering (SLS) has been successfully and broadly applied in biomedical engineering to fabricated biomedical part. And the porosity and microstructure of part can be controlled by main sintered parameters. This research focused aliphatic Polycarbonate (PC) sintered with SLS. According to the orthogonal experiment, the effect of laser power energy and interaction between main sintered parameters on porosity has been studied. Then the micro structure and mechanical properties of specimens sintered with the best optimal parameters have been analyzed.


2010 ◽  
Vol 113-116 ◽  
pp. 1845-1848 ◽  
Author(s):  
Wei Liang Zeng ◽  
Yan Ling Guo ◽  
Zong Sheng Xin ◽  
Kai Yi Jiang

In this paper, Wood-Plastic Composite(WPC) is successfully developed to make parts by Selective Laser Sintering(SLS) rapid prototyping (RP) process according to its advantages, such as green biological, wood texture and recycled, but the most important advantage is low-cost. With optimal design of components, the parts made by WPC have good mechanical properties as well as with good laser sintering properties. In order to further improve the mechanical properties of the parts, the post-processing–infiltrating with wax–is introduced. Through post-processing, the void fraction is decreased from from 51% to 7%, the mechanical properties are significantly improved, the average tensile strength, bending strength, impact strength are 1.214 MPa, 2.73 MPa and 1.4125 kJ/m2, compared with those without post processing, the tensile strength is 87 times, the bending strength is 4.7 times and impact strength is 2.5 times, respectively.


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