scholarly journals Optimal design of three-dimensional non-uniform nylon lattice structures for selective laser sintering manufacturing

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401879083 ◽  
Author(s):  
Xin Jin ◽  
Guo Xi Li ◽  
Meng Zhang
Keyword(s):  
Mechanical Properties ◽  
Topology Optimization ◽  
Optimal Design ◽  
Cell Size ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Manufacturing Constraints ◽  
Lattice Structures ◽  
Cell Type

As a kind of novel multifunctional structure with three-dimensional pores characterized by low relative density, lattice structures can attain a lightweight design while maintaining high specific mechanical properties in three-dimensional solid structures. Focusing on the challenge of finding the optimal design of lattice structures in the design object, a design and modeling method of non-uniform three-dimensional lattice structures is proposed while ensuring the selective laser sintering manufacturability. Optimization for cell type, cell size, and strut size distribution of lattices is specified with the mechanical properties analyzed and the material model calculated beforehand. The manufacturing constraints are analyzed and expressed in topology optimization and the optimal distribution of topology optimization results is mapped to the strut size distribution of lattice cells. The rapid and automatic computer-aided design modeling of optimized structures is realized by the parametric definition and assembling of lattice components. Finally, the non-uniform structures are successfully manufactured by selective laser sintering and it is shown by means of finite element analysis and experiments that the proposed design approach can improve the mechanical performance compared to the uniform lattice structure under the same weight reduction. And for the design object in this study, body-centered structure with cell size [Formula: see text]mm is chosen as the optimal cell type and cell size under the given selective laser sintering manufacturing constraints.

scholarly journals Finite element analysis and experimental study of plastic lattice structures manufactured by selective laser sintering

2016 ◽  
Vol 231 (1-2) ◽  
pp. 171-178 ◽  
Author(s):  
Jie Niu ◽  
Hui Leng Choo ◽  
Wei Sun
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Experimental Study ◽  
Finite Element ◽  
Selective Laser Sintering ◽  
Laser Sintering ◽  
Periodic Lattice ◽  
Triangular Prism ◽  
Lattice Structures ◽  
Element Analysis

The availability of additive manufacturing technologies in particular the selective laser sintering process has enabled the fabrication of high strength, lightweight and complex cellular lattice structures. In this study, the effective mechanical properties of selective laser sintering produced periodic lattice structures were investigated. Three different types of lattice structures were designed by repeating three types of open-form unit cells consisting of triangular prism, square prism and hexagonal prism. A novel approach of creating the complex and conformable lattice structures using traditional modelling software such as Creo® proposed by the authors was used. Based on the predesigned lattice structures, finite element analysis was carried out to evaluate the mechanical properties of these structures. For the experimental study, nylon samples were printed using a plastic selective laser sintering system and tested using a universal testing machine. Finite element analysis results show that lattice structures with triangular prism perform better than the other two prisms in terms of Young’s modulus to relative density ratio. Tensile tests results show good conformance with the results obtained from finite element analysis.

scholarly journals Bioactive Tetracalcium Phosphate Scaffolds Fabricated by Selective Laser Sintering for Bone Regeneration Applications

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2268 ◽  
Author(s):  
Tian Qin ◽  
Xiaoqian Li ◽  
Hui Long ◽  
Shizhen Bin ◽  
Yong Xu
Keyword(s):  
Mechanical Properties ◽  
Bone Regeneration ◽  
Laser Power ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Scaffold Material ◽  
Promising Candidate ◽  
Tetracalcium Phosphate ◽  
Good Biocompatibility

Tetracalcium phosphate (TTCP), a potential biological scaffold material, has attracted increasing interest for bone regeneration applications due to its good biodegradability and biocompatibility. In this research, three-dimensional porous TTCP scaffolds were manufactured via selective laser sintering (SLS), and an in-depth and meticulous study on the influence of laser power on the microstructure and mechanical properties of TTCP scaffolds was performed. The results showed that the TTCP particles fused together and formed a solid object due to the decrease in the number of micro-pores in the scaffold as the laser power increased from 6 W to 9 W. The maximum compressive strength that the scaffold could withstand and the strength of the fracture toughness were 11.87 ± 0.64 MPa and 1.12 ± 0.1 MPa·m1/2, respectively. When the laser power increased from 9 W to 10 W, the TTCP grains grew abnormally, resulting in diminished mechanical properties. The bioactivity tests showed that the surfaces of the scaffolds were entirely covered by bone-like apatite layers after soaking in simulated body fluid (SBF) for three days, indicating that the scaffolds exhibit excellent bioactivity. Moreover, cell experiments showed that the TTCP scaffolds had good biocompatibility. This study indicated that SLS-fabricated TTCP scaffolds may be a promising candidate for bone regeneration applications.

On Mechanical Properties of Cellular Steel Solids With Shell-Like Periodic Architectures Fabricated by Selective Laser Sintering

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Oraib Al-Ketan ◽  
Reza Rowshan ◽  
Anthony N. Palazotto ◽  
Rashid K. Abu Al-Rub
Keyword(s):  
Mechanical Properties ◽  
Material Selection ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Laser Sintering ◽  
Cellular Materials ◽  
Structure Property ◽  
Printing Quality ◽  
High Control ◽  
Proper Material

Historically, the approach in material selection was to find the proper material that serves a specific application. Recently, a new approach is implemented such that materials are being architected and topologically tailored to deliver a specific functionality. Periodic cellular materials are increasingly gaining interest due to their tunable structure-related properties. However, the concept of structure–property relationship is not fully employed due to limitations in manufacturing capabilities. Nowadays, additive manufacturing (AM) techniques are facilitating the fabrication of complex structures with high control over the topology. In this work, the mechanical properties of additively manufactured periodic metallic cellular materials are investigated. The presented cellular materials comprise a shell-like topology based on the mathematically known triply periodic minimal surfaces (TPMS). Maraging steel samples with different topologies and relative densities have been fabricated using the powder bed fusion selective laser sintering (SLS) technique, and three-dimensional printing quality was assessed by means of electron microscopy. Samples were tested in compression and the compressive mechanical properties have been deduced. Effects of changing layer thickness and postprocessing such as heat treatment are discussed. Results showed that the diamond TPMS lattice has shown superior mechanical properties among the examined topologies.

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.

scholarly journals Estimation of the compression strength and surface roughness of the as-built SLS components using weibull distribution

2021 ◽  
pp. 1-6
Author(s):  
Hamaid Mahmood KHAN
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Compressive Strength ◽  
Weibull Distribution ◽  
Selective Laser Sintering ◽  
Three Dimensional ◽  
Random Variable ◽  
Production Quality ◽  
Laser Source ◽  
Distribution Method

Selective laser sintering (SLS) is a process of fabrication of three-dimensional structures by fus- ing powder particles using a guided laser source. The uncertainty in the mechanical properties of the SLS parts fabricated at the same time and with the same process parameters can affect the repeatability of the SLS process. A vast difference in the mechanical properties of the concurrently processed parts can lower the production quality of the batch. Therefore, the param- eters are required to be design based on the most probable outcome of the desired properties. Weibull distribution is one such statistical-based probability distribution method to measure the likelihood of the occurrence of a value of any random variable falling within a particular range of values. Here, the Weibull distribution was used to measure the relative likelihood (90% probability) of the surface roughness and the compressive strength values of the SLS-built polyamide PA2200 components in the given sample space that was obtained from 20 random samples. The results show that the variance in the surface roughness (scan and built plane) and the compressive strength values were in the range of 6–7 μm and around 10 MPa, respectively. Moreover, the surface roughness of the two orthogonal planes with 90% reliability was measured at 14.81 μm (scan plane) and 12.15 μm (built plane). Similarly, the yield strength and the compressive strength with 90% reliability were found 25.87 MPa and 62.64 MPa, respectively.

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