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1.
Janaina Lisi Leite Gean Victor Salmoria Rodrigo A. Paggi Carlos Henrique Ahrens Antonio Sérgio Pouzada 《The International Journal of Advanced Manufacturing Technology》2012,59(5-8):583-591
The use of selective laser sintering in the production of functional gradient materials offers advantages, as freeform construction and localized control of the composition and process parameters, compared to other rapid manufacturing processes. In this work, selective laser sintering was used for manufacturing three-dimensional parts in functionally graded polymer blends based on polyamide 12 and high-density polyethylene with gradient composition in two directions (Y and Z). Test specimens were prepared in PA12/HDPE ratios of 0/100, 20/80, 50/50, 80/20 and 100/0 (w/w). These specimens were assessed in terms of density, microstructure by scanning electron microscopy and polarized light microscopy and mechanical performance by DMA. The sintered binary blend systems with composition gradient showed microstructure and properties variation as function of the blend compositions. The results demonstrated the potential of selective laser sintering to manufacture advanced polymeric functional gradient material parts. 相似文献
2.
Jinhui Liu Zhongliang Lu Yusheng Shi Wenwu Xu Jing Zhang 《The International Journal of Advanced Manufacturing Technology》2010,48(1-4):155-163
Cooling system of an injection mold is important for the promotion of production rate and the quality of injection plastic components. Conformal cooling channels are newly developed temperature-adjusting method to promote the efficiency of cooling system. They can be made in the injection mold inserts via the method of indirect selective laser sintering combined with traditional powder metallurgy. This work discussed some processes such as thermal transmission, powders removing, and metal melt infiltration during the manufacturing of the mold inserts in detail. The result showed that redundant powders outside of laser-scanned areas might be sintered together with the sintered parts owing to the accumulation of laser energy during sintering process. This was solved by switching the temperature to initial level after one layer had been sintered. A limit length corresponding to some certain power vacuum system was found when the removal of unsintered powders in the cooling channels was carried out. Therefore, some subsidiary channels leading the cooling channels outside were made to help the removal of powders within the cooling channels. Dripping method was adopted during metal melt infiltration process, which was proven to be relevant for maintaining of the final shape of infiltrated inserts. 相似文献
3.
J. H. Liu Y. S. Shi K. H. Chen S. H. Huang 《The International Journal of Advanced Manufacturing Technology》2007,33(7-8):693-697
The property of alloy parts can be adjusted conveniently if alloy element powders are used for manufacturing alloy parts by
indirect selective laser sintering (SLS), but there have been no reports in this field. Fe, Cu, Ni, C composite powders of
two compositions were obtained through a 3D blending way in this paper. Green parts of above composite powder were manufactured
by indirect SLS. Then, Cu matrix Fe-Cu-Ni-C alloy composites were produced after green parts had been depolymerized, high
temperature sintered and infiltrated by molten Cu. The post-processing of green parts, microstructure and mechanical properties
of alloy composites were investigated. The results show: Ni, Cu and C diffuse into γ-Fe when green parts are being sintered
at high temperature and the distributing non-uniformity of alloy elements is eliminated basically; at room temperature, alloy
composite microstructures are composed of lower bainite, α-Cu precipitated out of γ-Fe and Fe-Ni after they have been solution
treated at 930°C and held at 350°C for 1 h later; the yield strength of alloy composites is near to 400 MPa and the elongation
is under 3%. It can be used for manufacturing injection mold or other functional parts by indirect SLS. 相似文献
4.
研究了激光选区烧结(SLS)成型工艺中不同工艺参数以及后续热处理工艺对超高分子量聚乙烯(UHMWPE)材料成型性能的影响。通过调整扫描间距、激光功率、扫描速度等不同工艺参数,描述了SLS成型UHMWPE零件的致密度、拉伸强度以及断裂伸长率,并对热处理前后的SLS成型UHMWPE零件的力学性能进行了比较。结果显示,致密度、拉伸强度、断裂伸长率总体上与激光功率呈正相关关系,与扫描间距、扫描速度呈负相关关系。经热处理后,SLS成型UHMWPE零件的力学性能有明显提高,致密度达到95.12%,抗拉强度达到24.08 MPa,断裂伸长率达到334.82 MPa。实验结果表明:SLS成型UHMWPE零件与模塑成型UHMWPE零件性能尚有差距,仅优化成型工艺不足以得到理想性能,但经热处理后,零件性能基本满足使用要求。 相似文献
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Sharma Faladrum Dixit Uday Shanker 《Journal of Mechanical Science and Technology》2019,33(9):4439-4449
A fuzzy set based cost model for additive manufacturing is proposed. The model is illustrated through an example of selective laser sintering (SLS), a commonly used additive manufacturing (AM) process. Initially, a deterministic cost model is developed. It is then converted to a fuzzy set based model by considering uncertainty in build time estimation and cost components. For the specific case of SLS, a build time estimation procedure is developed as a part of the cost model. A method to evaluate the reliability of the cost estimate in AM and its significance is also introduced. The cost model is illustrated through two examples of products manufactured by SLS.
相似文献7.
选择性激光烧结主要成型材料的研究进展 总被引:1,自引:0,他引:1
简要介绍了选择性激光烧结的原理以及特点,比较和分析了几种选择性激光烧结主要成型材料的特点和国内外的研究现状,展望了选择性激光烧结材料的展前景. 相似文献
8.
Song Changhui Huang Aibing Yang Yongqiang Wang Di Yu Jia-kuo 《The International Journal of Advanced Manufacturing Technology》2016,87(5-8):1217-1228
Life cycle assessment (LCA), as an assessment tool for environmental performance, is used widely in decision making of product design. However, apparently, it is not sufficient to make final decision only depending on environmental assessment results for profit-directed organizations. One of the main purposes of this paper is to propose a methodology for integration of LCA and economic analysis tool-life cycle costing (LCC) in order to get the integrated evaluation results. A framework of integration of LCA and LCC has been introduced, which is contained by four components: the definition of unity time and physical boundaries, integration of inventory analysis, integration of impact assessment, environmental and economic interpretation. However, the integrated evaluation results always indicate that the relationship between economic and environmental performance is not in balance. Optimization is as important as integration to eco-balance. An optimization method is proposed to improve the initial product design with maximizing the integrated environmental and economic benefit for mechanical product. In optimization step, product system is divided two parts with environmental subsystem and economic subsystem. The integrated evaluation results are adopted to support for the optimization. Some mathematic optimization models are set up for environmental and economic subsystems. Multidisciplinary design optimization is applied to optimize these models so that the initial mechanical product design can achieve the best environmental and economic performance result. A case study of type 4135G diesel engine is presented to validate the rationality and feasibility. 相似文献
9.
Mario Ganci Wei Zhu Gianluca Buffa Livan Fratini Song Bo Chunze Yan 《The International Journal of Advanced Manufacturing Technology》2017,91(9-12):3169-3180
A numerical approach to model the selective laser sintering (SLS) of polypropylene is proposed. A 3D thermal model was developed and thus enables the prediction of the temperature fields and the extension of the sintered area in the powder bed taking into account the phase change during multiple laser passes. Powder–liquid, liquid–solid and solid–liquid phase changes were modelled during the SLS and the subsequent cooling processes. Then, a 3D thermomechanically coupled model was set up based on the temperature results of the thermal model in order to predict the distortion of the produced parts after cooling down. Different pre-heating temperatures were considered, highlighting their influence on the final part properties. 相似文献
10.
Fred L. Amorim Armin Lohrengel Norbert Müller Guenter Schäfer Tiago Czelusniak 《The International Journal of Advanced Manufacturing Technology》2013,65(9-12):1423-1428
Electrical discharge machining (EDM) is a nonconventional machining process widely applied for the manufacture of intricate shapes in hard materials which are not easily machined by conventional machining processes. The production of geometrically complex EDM electrodes is difficult, time consuming, and it can account for about 50 % of the total process costs. Selective laser sintering (SLS) can be an alternative technique to produce EDM electrodes in a faster way. This work conducted an experimental study on the performance of EDM electrodes made by SLS using pure copper, bronze–nickel alloy, copper/bronze–nickel alloy, and steel alloy powders. Important EDM performance measures such as material removal rate and volumetric relative wear were investigated and discussed for finishing, semifinish, and roughing regimes. This work contributes with an insight into the production of EDM electrodes via selective laser sintering, as an alternative technique to conventional machining processes, as well as to evaluate the performance of the electrodes, and also provide directions for future research on this field. 相似文献
11.
H. Chang C. S. Jwo P. S. Fan S. H. Pai 《The International Journal of Advanced Manufacturing Technology》2007,34(3-4):300-306
Using an innovative nanofluid preparation method, ultrasonic-aidedsubmerged arc nanoparticle synthesis system, this paper
employs the robustness design method to examine the optimal parameters, such as peak current, pulse duration, open voltage
and amplitude of ultrasonic vibration, for obtaining the optimal process for TiO2 nanofluid preparation. Experimental results show that the proposed manufacturing system can successfully prepare uniformly
distributed TiO2 nanoparticle using the optimal parameters. The pH of the as prepared TiO2 nanofluid is 7.5, which is much higher than that of isoelectric point, about 4.4. Hence, the suspended TiO2 nanoparticles already possess electrostatic stability properties. Regarding ultraviolet/visible absorbency, the produced
TiO2 nanofluid would absorb UV energy when the wavelength is 280 nm to 400 nm. According to the UV-Vis absorption spectrum analysis,
the energy band gap of the prepared TiO2 nanoparticle is 3.4 eV. 相似文献
12.
多零件选区激光熔化成型效率的优化 总被引:1,自引:1,他引:0
对多零件选区激光熔化的成型效率进行了优化.首先,分析了多零件选区激光熔化成型过程的时间消耗,并以减少时间消耗为目标建立了3维零件在3维成型空间中的2.5维排料优化规则.然后,研究了2.5维自动排料,提出利用3维零件模型在2维平面区域的投影将2.5维排料转化为2维排料的简化方法和一种利用切片数据进行投影生成的算法.最后,为验证所述方法的有效性,以手术模板模型为例,在虚拟选区激光熔化系统VDemetal280上进行了优化实验.与优化前相比,优化后的成型次数从4次降为3次,在扫描速度为600 mm/s、切片层厚为0.035 mm、扫描间距为0.08mm的工艺参数下,总铺粉次数从3 892次降为2 231次,预计加工时间从约91 276 s降为69 918 s,时间消耗有明显减少. 相似文献
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I. Konstantinou G-C. Vosniakos 《The International Journal of Advanced Manufacturing Technology》2018,98(1-4):29-35
The surface micro/nano-topographical modifications have been widely used in improving the biocompatibility of biomedical implants. In this paper, the feasibility of the micro-milling process for construction of micro-grooves without burrs on titanium alloy materials was investigated. Low melting point alloy was selected as supporting material to extend the boundary of the workpiece, so the burrs produced on the surface of supporting material. A novel hierarchical micro/nano-topography with micro-grooves and TiO2 nanotubes was fabricated on titanium alloy surface combining micro-milling and anodic oxidation. The scanning electron microscope, energy-dispersive spectroscopy, laser scanning microscope, and contact angle tester were used in characterizing surface features of machined workpieces. Results showed that the micro-grooves with dimension of 40 μm in depth were machined using V-shaped cutting tool, and the TiO2 nanotubes with dimension of 70 nm in diameter were superimposed on the surfaces of micro-grooves by anodic oxidation. In addition, the hydrophilicity of micro/nano-structured surface was significantly enhanced with the water contact angle decreasing from 114.8° to 60.3°. It is concluded that this hybrid method combining micro-milling technology and anodic oxidation can be used in improving the biological activity of biomedical implants through changing surface topographies. 相似文献
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16.
A multifactorial model is proposed for the surface microgeometry after selective laser sintering of metal powder. The dependence of the microgeometry on the following dominant factors is established: the laser power, the speed of the laser beam, and the scanning increment. 相似文献
17.
基于选择性激光烧结生物陶瓷复合粉体的工艺研究 总被引:1,自引:0,他引:1
主要研究了复相陶瓷Al2O3-ZrO2-SiO2单层烧结工艺,采用Nd:YAG激光器通过选择性激光烧结(SLS)成型复相陶瓷Al2O3-ZrO2-SiO2,实现了在不添加粘结剂、不作任何后处理的情况下激光束完全熔化样品。采用试验设计法系统地分析了激光烧结各项工艺参数对单层烧结质量的影响。利用SEM、XRD分析了不同工艺参数下单层烧结的显微结构以及对试样性能的影响,并通过试验确定最优工艺参数。而后,分别研究了t-ZrO2相对复合粉体的增韧效果与莫来石对改善零件强度所起的作用,对改善零件整体寿命和可靠性有着重要的意义。 相似文献
18.
Gean V. Salmoria Eduardo A. Fancello Carlos R. M. Roesler Frederic Dabbas 《The International Journal of Advanced Manufacturing Technology》2013,65(9-12):1529-1534
This paper presents a study on the effect of hydroxyapatite (HA) content on the microstructure and mechanical properties of high-density polyethylene (HDPE)/HA composites and the fabrication of functional graded scaffold of HDPE/HA by selective laser sintering (SLS). The microstructure of the sintered composite scaffolds had interconnected pores with diameters of 30–180 μm and porosity of 45–48 %. The HDPE/HA composite scaffolds had a flexural modulus of 36–161 MPa and ultimate strength of 4.5–33 MPa. The maximum loss modulus peak tended toward lower temperature values for HDPE/HA composites with 10 and 20 % of HA content, indicating that the αχ relaxation was slightly affected by higher quantities of HA. The HA particles reinforced the matrix and minimized the plastic and definitive deformation under the test conditions. HDPE/HA functional graded scaffold fabricated using SLS with controlled microstructure and properties showed considerable potential for biomedical applications, being suitable for bone and cartilage tissue engineering. 相似文献
19.
K. A. BARTELS R. H. CRAWFORD S. DAS S. GUDURI A. C. BOVIK K. R. DILLER S. J. AGGARWAL 《Journal of microscopy》1993,169(3):383-389
We discuss and give examples of the use of selective laser sintering to fabricate solid macroscopic models of microscopic specimens that have been imaged with a confocal microscope. The digital image processing necessary to create structurally sound models of both translucent and opaque specimens is presented. The fabricated models offer the ultimate in data visualization since they can be physically handled and manipulated to investigate the shape and features of the specimen. Such a powerful visualization tool is useful in both research and educational environments. 相似文献