scholarly journals Dimensional Accuracy of Models Manufactured by Selective Laser Sintering Technology

2019 ◽  
pp. 0787-0790
Author(s):  
Tomasz Kozior ◽  
Stanislaw Adamczak ◽  
Michal Skrzyniarz ◽  
Pawel Zmarzly ◽  
Damian Gogolewski
Keyword(s):  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Laser Sintering

Formability of the Layer Additive Ceramic Part

2008 ◽  
Vol 594 ◽  
pp. 241-248 ◽  
Author(s):  
Fwu Hsing Liu ◽  
Yunn Shiuan Liao ◽  
Hsiu Ping Wang
Keyword(s):  
Surface Roughness ◽  
Laser Scanning ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Scanning Speed ◽  
Laser Sintering ◽  
Single Line ◽  
Laser Scanning Speed ◽  
Silica Slurry

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.

Experimental Study on Warping Height of PA12/HDPE Specimen by Selective Laser Sintering

2010 ◽  
Vol 43 ◽  
pp. 430-433
Author(s):  
Nai Fei Ren ◽  
Pan Wang ◽  
Yan Luo ◽  
Hui Juan Wu
Keyword(s):  
Process Parameters ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Sintering Process ◽  
Influence Of Process Parameters ◽  
Optimum Parameters ◽  
Scan Speed ◽  
The Relationship

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.

scholarly journals Selective Laser Sintering (SLS) and Post-Processing of Prosopis Chilensis/Polyethersulfone Composite (PCPC)

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3034
Author(s):  
Aboubaker I. B. Idriss ◽  
Jian Li ◽  
Yangwei Wang ◽  
Yanling Guo ◽  
Elkhawad A. Elfaki ◽  
...  
Keyword(s):  
Mechanical Strength ◽  
Particle Distribution ◽  
Low Cost ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Raw Material ◽  
Post Processing ◽  
Prosopis Chilensis

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.

Investigation on selective laser sintering of PA12: dimensional accuracy and mechanical performance

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Achille Gazzerro ◽  
Wilma Polini ◽  
Luca Sorrentino
Keyword(s):  
Mechanical Performance ◽  
Selective Laser Sintering ◽  
Central Zone ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Point Of View ◽  
Content Type ◽  
Mechanical Performances ◽  
The Many ◽  
Additional Support

Purpose Selective laser sintering (SLS) has passed other techniques, thanks to its high print resolution, its ability to print microscale geometries without any additional support, its surface quality and its long-term thermal stability. However, despite the many advantages of SLS compared to fusion deposition modelling, there are still today some limitations on the materials to be printed. A limit critical from an industrial point of view is the aging of PA12 powder, i.e. the degradation of its physical and chemical performances, due to the high temperatures and the long printing cycles, thus involving a decrease of the mechanical properties of the printed parts. The purpose of this study was to charaterize mechanically and dimensionally specimens printed in PA12 through SLS by means of virgin or aged powder, i.e. powder just used for five printing cycles. Design/methodology/approach To achieve this aim, a set of specimens were designed, built, measured and mechanically tested; the obtained results were put into relationship with the values of the process parameters used to print them. Statistical tools to design the experiments and to analyse the obtained results were used. Findings The results show that the SLS process carried out through a Sintratec machine on PA12 powder has a good repeatability. To obtain the best dimensional and mechanical performances, it is needed to use virgin powder and place the part in the central zone of the printing area. Originality/value There are no scientific articles dealing with the influence of both the aging of the powder and the manufacturing parameters on the dimensional and mechanical characterization of specimens printed with SLS technique in PA12.

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 ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Orthogonal Experiment ◽  
Selective Laser Sintering ◽  
Single Layer ◽  
Dimensional Accuracy ◽  
Amorphous Polymers ◽  
Laser Sintering ◽  
Temperature Fields ◽  
Post Processing ◽  
Forming Process

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.

The Optimization Design Study of Selective Laser Sintering Process Parameters on the Pro-Coated Sand Mold

2011 ◽  
Vol 55-57 ◽  
pp. 853-858
Author(s):  
Rong Cheng ◽  
Xiao Yu Wu ◽  
Jian Ping Zheng
Keyword(s):  
Layer Thickness ◽  
Process Parameters ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Process Variables ◽  
Scan Speed ◽  
Coated Sand

This paper presents experimental investigations on influence of important process parameters viz., laser power, scan speed, layer thickness, hatching space along with their interactions on dimensional accuracy of Selective Laser Sintering (SLS) processed pro-coated sand mold. It is observed that dimensional error is dominant along length and width direction of built mold. Optimum parameters setting to minimize percentage change in length and width of standard test specimen have been found out using Taguchi’s parameter design. Optimum process conditions are obtained by analysis of variance (ANOVA) is used to understand the significance of process variables affecting dimension accuracy. Scan speed and hatching space are found to be most significant process variables influencing the dimension accuracy in length and width. And laser power and layer thickness are less influence on the dimension accuracy. The optimum processing parameters are attained in this paper: laser power 11 W; scan speed 1200 mm/s; layer thickness 0.5 mm and hatching space 0.25 mm. It has been shown that, on average, the dimensional accuracy under this processing parameters combination could be improved by approximately up to 25% compared to other processing parameters combinations.

Comparison of Dimensional Accuracy for Different Investment Casting Shells and Binders Based on Selective Laser Sintering

2011 ◽  
Vol 120 ◽  
pp. 243-247 ◽  
Author(s):  
Qing Song Yan ◽  
Xu Xiong ◽  
Gang Lu ◽  
Hong Wan ◽  
Can Cheng Liu ◽  
...  
Keyword(s):  
Investment Casting ◽  
Colloidal Silica ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Ethyl Silicate ◽  
Comprehensive Properties ◽  
Variation Rate ◽  
Dimensional Variation ◽  
Production Cost Control

The dimensional accuracy of shells and binders of investment casting which incorporation with selective laser sintering is investigated. The results show that the dimensional accuracy of colloidal silica is higher than that of ethyl silicate, and the dimensional variation rate of investment casting shells produced with colloidal silica is much lower than ethyl silicate shells. Moreover, colloidal silica possesses better performance on environmental protection and production cost control. These indicate that the comprehensive properties of colloidal silica are better than that of ethyl silicate. Meanwhile, the average dimensional variation rate of the single colloidal silica shell and the ethyl silicate-colloidal silica alteration shell was almost identical and it was much lower than that of the other shells which were produced in this study. This means two kinds of shells are optimized in all five types of shells studied in the aspect of dimensional accuracy. The unique properties of two shells show clearly direction to choose the type of shell.

Influence of part’s geometrical properties on shrinkage and laser heat affected zone size at selective laser sintering

2019 ◽  
Vol 25 (1) ◽  
pp. 208-220
Author(s):  
Tomaz Brajlih ◽  
Urska Kostevsek ◽  
Igor Drstvensek
Keyword(s):  
Heat Affected Zone ◽  
Manufacturing Process ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Factorial Experiment ◽  
Future Research ◽  
Content Type ◽  
Geometrical Properties ◽  
Laser Heat

Purpose One of the main problems of selective laser sintering (SLS) manufacturing process is the dimensional accuracy of products. Main causes of dimensional deviations are material shrinkage and size of laser heat affected zone (LHAZ). This paper aims to present a new method of adapting SLS manufacturing shrinkage and LHAZ compensation parameters to the geometrical characteristics of processed parts to improve their accuracy. Design/methodology/approach The first part of this work presents a hypothesis asserting that the shrinkage and the LHAZ size depend on geometrical properties of products. A method that defines geometrical properties by numerical influence factors is described in the continuation. A multi-factorial experiment with adaptable test part is set up. Then, test builds are manufactured on an SLS machine and measured with a three-dimensional optical scanner. Afterwards, the results are analysed in relation to the presumed hypothesis. Findings The analysis of variance of multi-factorial experiment proves the hypothesis and the influence of the geometrical properties on the accuracy of the SLS manufacturing process. Afterwards, a part is manufactured with adapted values of compensation parameters and the archived accuracy is discussed. Research limitations/implications Presented research is limited on a single SLS material. Also, some numerical factors are directly linked to the build volume dimensions of the SLS machine that was used in the experiment. However, results can be generalised and some guidelines for shrinkage and LHAZ compensation method are presented. Also, some guidelines for future research are proposed. Practical implications Based on the presented results, it can be determined that using constant shrinkage and LHAZ values on an SLS machine will not yield the same results in terms of accuracy if the geometrical properties of parts change significantly. Social implications By correctly adapting compensation values, the overall achievable accuracy of the SLS process can be achieved, enabling a more reliable production of mass-customised end-user parts such as customised medical accessories and devices for example. Originality/value A similar method of numerically describing geometrical properties of part in regard to SLS and directly adapting shrinkage and LHAZ compensation values to them for every individual build has not yet been proposed.

A New Rice Husk-Plastic Composite Powder Preparation Process for Selective Laser Sintering Fabrication

2013 ◽  
Vol 750-752 ◽  
pp. 1577-1581
Author(s):  
Wei Liang Zeng ◽  
Yan Ling Guo ◽  
Ying Liu ◽  
Yan Ping Gong ◽  
Pei Feng Zhao ◽  
...  
Keyword(s):  
Rice Husk ◽  
Composite Powder ◽  
Selective Laser Sintering ◽  
Dimensional Accuracy ◽  
Laser Sintering ◽  
Basic Material ◽  
Preparation Process ◽  
Powder Preparation ◽  
Plastic Composite ◽  
Hot Melt

A new powder material, rice husk-plastic composite powder (RPC), was successfully developed for selective laser sintering (SLS) process. RPC is mainly composed of rice husk powder and a hot-melt adhesive powder, it is a green and biological material and its most important advantage is low-cost, but because the hull surface of rice is burr and not smooth, easily jammed between particles, poor mobility, is not the medium of easy flowing, so mixing process was successfully developed to prepare RPC powders. The preparation process is divided to three steps. First, before mix, the rice husk power is dried for reducing the hydrophilic nature of rice husk fiber and improving the wettability and the adhesion actions of the interface. Then, put the PES hot melt adhesive, the dried wood powder and the acetone solution which contain coupling agent and initiator together to mix evenly. At last, dry the basic material at the constant temperature of 45±2°C in the oven, add the organic filler and light stabilizer. Finally, RPC powder for SLS is got. As the result of SLS fabrication, part made by RPC powder is got, its mechanical properties and dimensional accuracy is satisfied.

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