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Selective Laser Sintering of PEEK 总被引:3,自引:0,他引:3
Polyetheretherketone (PEEK) is a good choice especially for manufacturing medical instruments or implants. These parts are typically produced by conventional manufacturing methods, like injection moulding. Selective Laser Sintering (SLS) could offer more flexibility. It enables the direct manufacturing of products with complex geometries. Although SLS of polymers like polyamide or polystyrene is a standard industrial process already, laser sintering of PEEK remains a challenge.This article will show for SLS of PEEK the necessary adaptations in systems technology and material modifications and discuss a step-by-step process implementation. Process boundaries are shown concerning temperature and energy input. The high influence of porosity, which could be varied from zero to 15%, on mechanical properties is shown. 相似文献
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基于选择性激光烧结技术的快速铸造 总被引:8,自引:0,他引:8
介绍了用选择性激光烧结(SLS)快速成型技术直接制造覆膜砂铸型(芯)的特点及工艺过程。结合铸件生产,分析研究了SLS铸型(芯)的工艺设计、三维实体造型及铸型后处理等过程中所遇到的问题。 相似文献
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This paper presents an experimental study into the production of particulate Silicon Carbide/Polyamide matrix composites via the selective laser sintering (SLS) process. FEPA standard SiC grit, F240, was blended with the commercially available Duraform Polyamide to produce blend compositions of 50 volume percent and 50 weight percent SiC for direct SLS processing. A full factorial experimental approach was applied to examine the effects and interactions of laser power, scan speed, line spacing and layer thickness with regard to the mechanical and physical properties of composite sintered parts. Analysis of results and discussions of parameter interactions and individual main effects especially with regard to part strength are also presented. 相似文献
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分析了SLS直接熔融低熔点性粉末材料成型时的控温机理,将整个逐层加工过程的控温工艺分为一般层控温和关键层控温.提出了一种基于线段求差的实体截面求差的关键层判断方法,以此来判断关键层能够快速、准确、稳定的判断出关键层.实现了SLS系统的自动控温,提高了SLS系统的自动化程度. 相似文献
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Fundamentals of Selective Laser Melting of alloyed steel powders 总被引:3,自引:0,他引:3
The successful fabrication of dense iron-based parts by selective laser melting (SLM) is still limited to a narrow range of materials. This study aims at gaining an understanding of the effect of elements such as oxygen, carbon, silicon, titanium and copper on the quality of two-dimensional and three-dimensional iron-based objects. The results are related to the effect of the elements on physical phenomena such as laser absorption, heat transfer, wetting and spreading of the melt, oxidation, Rayleigh instability and Marangoni convection. 相似文献
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Layered manufacturing (LM) is gaining ground for manufacturing prototypes (RP), tools (RT) and functional end products (RM). Laser and powder bed based manufacturing (i.e. selective laser sintering/melting or its variants) holds a special place within the variety of LM processes: no other LM techniques allow processing polymers, metals, ceramics as well as many types of composites. To do so, however, quite some different powder consolidation mechanisms are invoked: solid state sintering, liquid phase sintering, partial melting, full melting, chemical binding, etc. The paper describes which type of laser-induced consolidation can be applied to what type of material. It tries to understand the underlying physical mechanisms and the interaction with the material properties. The paper demonstrates that, although SLS/SLM can process polymers, metals, ceramics and composites, quite some limitations and problems cause the palette of applicable materials still to be limited. There is still a long way to go in tuning the processes and materials in order to enlarge the applicability of LM. This is not surprising if one compares it to the decades of R&D work devoted to tuning processes and materials for hot or cold forming, metal cutting (e.g. development of free machining steels), casting and injection moulding (including powder injection moulding: MIM, CIM, etc.). 相似文献
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选择性激光烧结(Selective Laser Sintering,SLS)是快速成形技术的一种,其成形效率是需要考虑的重要指标之一。为了提高成形效率,我们从机械和工艺两方面着手研究和改进,并在华中科技大学研制的HRPS-III型SLS快速成形系统中应用,取得了良好的效果。 相似文献
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Coalescence Behaviour of Two Metallic Particles as Base Mechanism of Selective Laser Sintering 总被引:1,自引:0,他引:1
In many R&D places, the process of Selective Laser Sintering (SLS) of high performance metals is subject of investigations. An observation often made in SLS of metals is, that certain materials show a proper bonding behaviour while others tend to form welding pearls («balling» effect). This paper aims to identify and explain process mechanisms related to this effect. The dominating physical mechanisms are investigated. In addition, it is described which material properties mainly affect the results. The attained insights are transferred to the conditions of SLS in a powder bed layer by process modelling and experimental testing. 相似文献
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提高SLS覆膜砂铸型(芯)强度的措施 总被引:6,自引:2,他引:4
分析了影响覆膜砂铸型(芯)烧结强度的因素,详细地讨论了提高选择性激光烧结(SLS)覆膜砂铸型(芯)烧结强度的各种措施。从烧结方式上探讨了如何既提高SLS制件强度、又保证制件的成形速度和精度的问题。 相似文献
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基于SLS原型的快速(重力)铸造工艺 总被引:4,自引:0,他引:4
结合SLS快速成形和铸造工艺可以实现金属零件的快速铸造.根据原型材料可熔融和烧失的特性,制定了类似于熔模铸造的快速铸造工艺方案.讨论了快速金属铸件的特点,对快速铸造工艺提出了成功率高、成形性好和性能较高的要求.分析了面向金属零件快速铸造的重力铸造工艺并以实例说明,顶注式浇注系统适用于结构简单且高度不大的快速零件,而阶梯式浇注系统适用于中大型和复杂程度较高的铸件. 相似文献
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This study presents an experimental investigation to improve Selective Laser Melting (SLM) regarding aspects such as surface roughness, density, precision and micro machining capability by employing secondary processes such as Selective Laser Erosion (SLE) and laser re-melting. SLM is a layered additive manufacturing technique for the direct fabrication of functional parts by fusing together metal powder particles. Laser re-melting, applied after each layer or only on the top surfaces, is used to improve the roughness and density while SLE, a subtractive process, is combined with SLM to improve the precision and micro machining capability. 相似文献
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The analysis of techniques and problems in the fabrication of cutting tools based on super hard composites results in a solution by the application of lasers. The results of systematic study of diamond composites sintering with laser radiation are discussed. A mathematical modeling of the heat transfer process at high speed laser beam scanning has resulted in connections between working conditions and irradiated material characteristics. Experimental results of the influence of the laser parameters on the diamonds strength, the reliability of their fixing and composite materials structure changes are demonstrated. The possibilities to use new bonding materials based both on iron or other metals to improve the workability of the cutting tools are discussed. 相似文献
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采用选择性激光烧结(Selective laser sintering,SLS)和选择性激光熔化(Selective laser melting,SLM)工艺,分别进行了铁基合金粉末的快速成形试验,对比分析了SLS与SLM成形机理、相应的工艺参数以及它们对测试件成形过程、金相组织与力学性能的影响。结果表明:由于成形机理不同,相对于SLS技术,采用SLM能够制造高致密度、组织均匀、力学性能良好的金属零件,但容易出现翘曲变形、裂纹与球化现象。通过制定合适的材料与工艺参数能够避免上述缺陷。 相似文献
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选择性激光烧结的翘曲变形与扫描方式的研究 总被引:2,自引:0,他引:2
在研究选择性激光烧结工艺(Selective Laser Sintcfing,简称SLS)成形误差的基础上,分析造成SLS成形件翘曲的原因,构建了一种新的翘曲变形模型.并以此模型作为基础,提出一种新的光栅扫描方式.通过试验验证,此扫描方式可以有效地降低SLS成形件的翘曲变形,提SLS成形件精度. 相似文献
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激光重熔使得材料表面的固化层再次快速熔化、凝固,从而提高了材料的致密度和表面质量。作为一种表面改性技术,激光重熔已经在传统制造工艺中得到了广泛的应用。近期研究表明,激光重熔技术也可以应用到选区激光熔化(SLM)中,实现消除缺陷并优化组织结构。激光重熔技术还可以提高零件的硬度和延展性等力学性能。本文主要总结了激光重熔对于常见SLM成形金属材料的质量提升作用,激光重熔工艺手段以及重熔参数(重熔激光功率、重熔扫描速度、重熔扫描间距和重熔次数)对于缺陷消除、组织结构优化的作用规律。 相似文献
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Dongdong Gu Yves-Christian HagedornWilhelm Meiners Konrad WissenbachReinhart Poprawe 《Surface & coatings technology》2011,205(10):3285-3292
A novel Selective Laser Melting (SLM) process was applied to prepare bulk-form TiC/Ti5Si3 in-situ composites starting from Ti/SiC powder system. The influence of the applied laser energy density on densification, microstructure, and mechanical performance of SLM-processed composite parts was studied. It showed that the uniformly dispersed TiC reinforcing phase having a unique network distribution and a submicron-scale dendritic morphology was formed as a laser energy density of 0.4 kJ/m was properly settled. The 96.9% dense SLM-processed TiC/Ti5Si3 composites had a high microhardness of 980.3HV0.2, showing more than a 3-fold increase upon that of the unreinforced Ti part. The dry sliding wear tests revealed that the TiC/Ti5Si3 composites possessed a considerably low friction coefficient of 0.2 and a reduced wear rate of 1.42 × 10− 4 mm3/Nm. The scanning electron microscope (SEM) characterization of the worn surface morphology indicated that the high wear resistance was due to the formation of adherent and strain-hardened tribolayer. The densification rate, microhardness, and wear performance generally decreased at a higher laser energy density of 0.8 kJ/m, due to the formation of thermal cracks and the significant coarsening of TiC dendritic reinforcing phase. 相似文献