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Dynamic Healable Polyurethane for Selective Laser Sintering
摘要： Selective laser sintering (SLS) is one of the mainstream 3D printing technologies. A major challenge for SLS technology is the lack of novel polymer powder materials with improved Z-direction strength. Herein, a dynamic polymer was utilized to solve the challenge of SLS. To verify this concept, novel cross-linked poly(chlorophenol-urethane) (PCP-PU) and poly(bromophenol-urethane) (PBP-PU) containing dynamic halogenated bisphenol carbamate bond were examined. The obtained dynamic polyurethane exhibited excellent mechanical strength and self-healing efficiency, in addition to SLS processing ability. A small molecule model study confirmed the dynamic reversible characteristics of the chlorinated bisphenol carbamate, which dissociates into isocyanate and hydroxyl at 120 °C and reforms at 80 °C, as confirmed by NMR and FT-IR. SLS 3D printing using the self-made healable PBP-PU powders was successfully realized. The interface interaction between the adjacent SLS layers can be significantly improved via dynamic chemical bond linking instead of traditional physical entanglement, which leads to an improved Z-direction mechanical strength. The SLS processed PBP-PU sample exhibits an X-axis tensile strengths of ~23 MPa and an elongation at break of ~600%. The Z-axis tensile strength is ~88% of X-axis’s, much higher than that of control TPU sample (~56%).
关键词： 3D printing,self-healing,SLS,polyurethane
更新于2025-09-23 15:21:01
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Nanodot array deposition via single shot laser interference pattern using laser-induced forward transfer
摘要： Laser-induced forward transfer (LIFT) is a direct-writing technique capable of depositing a single dot smaller than the laser wavelength at small shot energy through the laser-induced dot transfer (LIDT) technique. To deposit a single nanodot in a single shot of laser irradiation, a liquid nanodrop is transferred from donor to receiver and finally solidified via a solid-liquid-solid (SLS) process. In conventional LIDT experiments, multi-shots with step scanning have been used to form array structures. However, interference laser processing can achieve an arrayed process and generate a periodic structure in a single shot. In this study, a femtosecond laser interference pattern was first applied to LIDT, and an array of nanodots was successfully deposited in a single shot, producing the following unit structures: a single dot, adjoining dots, and stacking dots. The diameter of the smallest nanodot was 355 nm, and the narrowest gap between two adjoining nanodots was 17.2 nm. The LIDT technique produces high-purity, catalyst-free that do not require post-cleaning or alignment processes. Given these significant advantages, LIDT can expand the usability of nanodots in a wide range of fields.
关键词： array,laser-induced dot transfer (LIDT),interference laser processing,nanodot,femtosecond laser,Au,solid-liquid-solid (SLS) mechanism
更新于2025-09-23 15:19:57
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The Influence of Selected Selective Laser Sintering Technology Process Parameters on Stress Relaxation, Mass of Models, and Their Surface Texture Quality
摘要： The article presents the results of research on the impact of basic process parameters of selective laser sintering technology on the mass of the produced models (density of the sintered material—polyamide PA 2200), stress relaxation during compression determined in accordance with the ISO 3384 standard, and geometric surface structure parameters (SGPs). During the tests, the influence of process parameters such as the location of the models on the virtual construction platform (printing direction), the density of the energy supplied to the sintered layer of powder, and the layer thickness of the manufactured material layer was taken into account. The test results confirmed that the process parameters have a significant impact on the density of the model material (in the sintered state), the mechanical properties (stress relaxation during compression), and the quality of the surface texture (SGPs). The most favorable positioning variants of the models on the construction platform were determined. The most favorable thickness variants of the combined layers and the density value of the energy supplied to the sintered powder layer were selected, depending on the expected mass, strength, and SGP quality. In addition, it has been shown that it is possible to build models with reduced mass (>20%), while maintaining satisfactory mechanical and qualitative properties of the surface texture.
关键词： additive manufacturing technologies,GPS,rapid prototyping,SLS,3D printing,stress relaxation
更新于2025-09-19 17:13:59
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A three dimensional meshfree-simulation of the selective laser sintering process with constant thermal coefficients applied to nylon 12 powders
摘要： 3D printing is an intersting process in the context of creating original objects.Selective laser sintering printers use a laser to fuse polyamide particles together with specific resin and heat. The difference in temperature between the different areas in the process causes the appearance of deformations, the objective of this work is the modeling of the thermal SLS phenomenona, by following the evolution of the temperature as a function of time.This model is based on the resolution of the heat conduction equation coupling with convection and radiation conditions with a distribution heat source and constant thermal coefficients by the meshless method based on radial basis function , the result of this study,will be presented and compared with other works.
关键词： heat transfer,Meshfree method,radical basis function (RBF),thermal modeling,selective laser sintering(SLS)
更新于2025-09-19 17:13:59
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Cluster Synchronization of Semiconductor Lasers Network with Heterogeneous Coupling Delays
摘要： The cluster synchronization of mutually coupled semiconductor lasers network with heterogeneous delays is systematically investigated, whose applicability is demonstrated by discussing two simple networks and a Gaussian-distribution with network random heterogeneous coupling delays.
关键词： Heterogeneous delays,Cluster synchronization,Random SLs network
更新于2025-09-16 10:30:52
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Experimental determination of material model of machine parts produced by Selective laser sintering (SLS) technology
摘要： The machine parts realized by additive production technologies are more and more frequently used as parts of machines. To achieve this an exact design process must be carried out, which in general is possible by numerical analysis. To fulfill correct calculation the material properties must be known. Earlier investigations pointed out that the orthotropic material model is suitable to describe the behavior of the model under external loads produced by additive technology. Analysis of this fact, and the material properties of this kind of materials have been investigated in this paper. The results of SLS technology have been compared with the results of other technologies.
关键词： material properties,material law,Additive manufacturing,SLS,experimental determination
更新于2025-09-12 10:27:22
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Catalyst-Assisted Solution–Liquid–Solid Synthesis of CdS/CuInSe <sub/>2</sub> and CuInTe <sub/>2</sub> /CuInSe <sub/>2</sub> Nanorod Heterostructures
摘要： Axial nanowire heterostructures composed of cadmium sulfide (CdS)/copper indium diselenide (CuInSe2) and copper indium telluride (CuInTe2)/copper indium diselenide (CuInSe2) were synthesized by a solution?liquid?solid (SLS) method with the catalyzer of bismuth nanocrystals. Electron microscopy and diffraction studies show CuInTe2 and CuInSe2 segments growing along the [112] direction with a clear epitaxial interface between them. In CdS/CuInSe2 nanorod heterostructures, CuInSe2 and CdS segments grow along the [112] and [111] direction, respectively, with an obvious epitaxial interface between them. Energy-dispersive X-ray spectrometry demonstrates the alloy-free composition modulation in two nanorod heterostructures. In CuInTe2/CuInSe2 nanorod heterostructures, Te and Se are localized in CuInTe2 and CuInSe2 segments, respectively. Cu/In/Se and Cd/S are localized in the CuInSe2 and CdS sections of the CdS/CuInSe2 nanorod heterostructures. This research confirms that the SLS mechanism provides a general alternate technique to prepare multicomponent axial 1D heterostructures that have been difficult to generate by using either catalyst-free solution-phase synthesis or vapor?liquid?solid growth.
关键词： epitaxial interface,nanowire heterostructures,solution?liquid?solid (SLS) method,bismuth nanocrystals,energy-dispersive X-ray spectrometry
更新于2025-09-04 15:30:14