Effects of energy density on morphology and properties of selective laser sintered polycarbonate
Effects of energy density on morphology and properties of selective laser sintered polycarbonate
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DOI：
10.1016/s0924-0136(99)00007-2
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发表时间：
1999-05-19
影响因子：
6.3
通讯作者：
Cheung, WL
中科院分区：
文献类型：
--
作者：
Ho, HCH;Gibson, I;Cheung, WL
采用选择性激光烧结（SLS）法制备了聚碳酸酯（PC）粉末。研究了激光能量密度在0.036 ~ 0.12 J mm（-2）范围内对烧结试样物理密度、拉伸性能和形貌的影响。在低能量密度水平下，试样的物理密度和抗拉强度随能量密度的增加而增加。在能量密度大于0.09 J mm-2的情况下烧结时产生烟雾，表明PC粉发生了降解。这些试样呈微黄色，密度和抗拉强度降低。在低能量密度下构建的样品中，扫描电子显微镜（SEM）显示PC颗粒表面发生轻微融合。单个粒子可以被识别，粒子之间的空隙相互连接。拉伸断裂过程中裂纹在颗粒间扩展。当能量密度高时，粉末被彻底融合，从而可以构建更致密的结构。扫描电镜还显示，在PC粉末的各个层内，融合更有效，而层之间存在相当数量的空隙。因此，预计垂直于各层的构件强度将低于各层的面内强度。在高能量密度下，试样的断口表面出现了波纹状的圆形特征。这些特征通常出现在脆性塑料的断口表面。为选择性激光烧结PC功能产品的生产奠定了基础。(C) 1999 Elsevier Science S.A.版权所有
Selective laser sintering (SLS) was used to prepare components from polycarbonate (PC) powder. The effects of energy density of the laser beam, ranging from 0.036 to 0.12 J mm(-2), on the physical density, tensile properties and morphology of the sintered specimens were investigated. At low energy density levels, the physical density and tensile strength of the specimens were found to increase with the increase in energy density. Smoke was observed when the components were sintered under an energy density above 0.09 J mm-2, which suggests degradation of the PC powder. These specimens appeared slightly yellow and there was a reduction in the density and tensile strength. In specimens built under a low energy density, scanning electron microscopy (SEM) showed that slight fusion occurred at the surface of the PC particles. The individual particles could be identified and the voids between the particles were interconnected. The crack propagated between the particles during tensile fracture. When the energy density was high, the powder was fused thoroughly which allowed a more dense structure to be built. SEM also showed that fusion was more effective within the individual layers of the PC powder, whilst considerable amounts of voids were present between the layers. Therefore, the strength of the components normal to the layers is expected to be lower than the in-plane strength of the layers. Some wavy circular features were observed on the fracture surfaces of the specimens built under a high energy density. Such features are commonly found on the fracture surfaces of brittle plastics. The work forms a basis for the production of selective laser sintered PC functional products. (C) 1999 Elsevier Science S.A. All rights reserved.