I-Form Advanced Manufacturing Research Centre, University College Dublin, Belfield, Dublin, 4, Ireland.
I-Form Advanced Manufacturing Research Centre, University College Dublin, Belfield, Dublin, 4, Ireland.
J Mech Behav Biomed Mater. 2020 Jun;106:103723. doi: 10.1016/j.jmbbm.2020.103723. Epub 2020 Mar 23.
Selective Laser Melting allows for the creation of intricate porous structures, that possess favourable biological properties. These structures are known as porous biomaterials. The focus of this paper is to evaluate the use of an in-line photodiode based process monitoring system, for the monitoring of the operational behaviour of the laser, and to correlate this with the resultant parts mechanical performance. In this study the production scale Renishaw 500M was used to produce porous structures, using Ti-6Al-4V feedstock powder. During the process, a co-axial process monitoring system was utilised to generate data relating to both the meltpool and the operational behaviour of the laser. An advanced scanning technique was used to produce the structures, whereby the laser parameters determine the strut dimensions. In this study, the laser input energy was reduced by 33%, 66% and 100%, at specific layers within the structures. Computer Tomography and Scanning Electron Microscopy was utilised to characterise the affected struts within the structures, while quasi-static compression testing was used to determine the structure's mechanical properties. It was demonstrated that as the level of input energy decreased and the number of affected layers increased, a corresponding decrease in the load bearing capacity of the structures occurred. With the structures experiencing a significant loss in strength also exhibiting a change in the failure mode during compression testing. Data generated during the processing of such structures was compared to the data generated during the processing of control structures, with the difference between the two been calculated on a layer-by-layer basis. A clear correlation was demonstrated between the total level of deviation between the two signal sets and a reduction in the load bearing capacity of the structures. This indicates that by comparing build data to a benchmark data set, valuable information relating to the structural integrity of the porous structures can be obtained.
选择性激光熔化允许创建具有有利生物特性的复杂多孔结构。这些结构被称为多孔生物材料。本文的重点是评估使用基于在线光电二极管的过程监测系统来监测激光的运行行为，并将其与所得零件的机械性能相关联。在这项研究中，使用 Renishaw 500M 生产规模生产多孔结构，使用 Ti-6Al-4V 原料粉末。在过程中，使用同轴过程监测系统生成与熔池和激光运行行为相关的数据。采用先进的扫描技术来生产结构，其中激光参数决定了支柱的尺寸。在这项研究中，激光输入能量在结构的特定层中分别减少了 33%、66%和 100%。计算机断层扫描和扫描电子显微镜用于表征结构内受影响的支柱，而准静态压缩测试用于确定结构的机械性能。结果表明，随着输入能量水平的降低和受影响层数量的增加，结构的承载能力相应降低。结构经历了显著的强度损失，同时在压缩测试中也表现出失效模式的变化。对处理此类结构生成的数据与处理对照结构生成的数据进行了比较，两者之间的差异是在逐层基础上计算的。两个信号集之间的总偏差水平与结构承载能力的降低之间显示出明显的相关性。这表明通过将构建数据与基准数据集进行比较，可以获得有关多孔结构结构完整性的有价值信息。
