Snodderly Kirstie Lane, Fogarasi Magdalene, Badhe Yutika, Parikh Ankit, Porter Daniel, Burchi Albert, Gilmour Laura, Di Prima Matthew
US Food and Drug Administration, White Oak, Silver Spring, Maryland, USA.
Chenega Professional Services, Anchorage, Alaska, USA.
3D Print Med. 2022 May 7;8(1):14. doi: 10.1186/s41205-022-00141-z.
Additive manufacturing (AM), commonly called 3D Printing (3DP), for medical devices is growing in popularity due to the technology's ability to create complex geometries and patient-matched products. However, due to the process variabilities which can exist between 3DP systems, manufacturer workflows, and digital conversions, there may be variabilities among 3DP parts or between design files and final manufactured products. The overall goal of this project is to determine the dimensional variability of commercially obtained 3DP titanium lattice-containing test coupons and compare it to the original design files.
This manuscript outlines the procedure used to measure dimensional variability of 3D Printed lattice coupons and analyze the differences in external dimensions and pore area when using laser and electron beam fabricated samples. The key dimensions measured were the bulk length, width, and depth using calipers. Strut thickness and pore area were assessed for the lattice components using optical imaging and µCT.
Results show a difference in dimensional measurement between printed parts and the computer-designed files for all groups analyzed including the internal lattice dimensions. Measurements of laser manufactured coupons varied from the nominal by less than 0.2 mm and results show averages greater than the nominal value for length, width, and depth dimensions. Measurements of Electron Beam Melting coupons varied between 0.4 mm-0.7 mm from the nominal value and showed average lengths below the nominal dimension while the width and depths were greater than the nominal values. The length dimensions of Laser Powder Bed Fusion samples appeared to be impacted by hot isostatic press more than the width and depth dimension. When lattice relative density was varied, there appeared to be little impact on the external dimensional variability for the as-printed state.
Based on these results, we can conclude that there are relevant variations between designed files and printed parts. However, we cannot currently state if these results are clinically relevant and further testing needs to be conducted to apply these results to real-world situations.
增材制造（AM），通常称为3D打印（3DP），由于其能够制造复杂几何形状和与患者匹配的产品，在医疗器械领域越来越受欢迎。然而，由于3DP系统、制造商工作流程和数字转换之间可能存在的工艺变异性，3DP零件之间或设计文件与最终制造产品之间可能存在变异性。本项目的总体目标是确定商业获得的含3D打印钛晶格测试 coupons 的尺寸变异性，并将其与原始设计文件进行比较。
本手稿概述了用于测量3D打印晶格 coupons 尺寸变异性的程序，并分析了使用激光和电子束制造样品时外部尺寸和孔隙面积的差异。测量的关键尺寸是使用卡尺测量的整体长度、宽度和深度。使用光学成像和µCT评估晶格组件的支柱厚度和孔隙面积。
结果显示，在分析的所有组中，包括内部晶格尺寸，打印零件与计算机设计文件之间的尺寸测量存在差异。激光制造 coupons 的测量值与标称值的差异小于0.2毫米，结果显示长度、宽度和深度尺寸的平均值大于标称值。电子束熔化 coupons 的测量值与标称值的差异在0.4毫米至0.7毫米之间，显示平均长度低于标称尺寸，而宽度和深度大于标称值。激光粉末床熔融样品的长度尺寸似乎比宽度和深度尺寸更容易受到热等静压的影响。当晶格相对密度变化时，对于打印状态的外部尺寸变异性似乎影响很小。
基于这些结果，我们可以得出结论，设计文件和打印零件之间存在相关差异。然而，我们目前无法确定这些结果是否具有临床相关性，需要进行进一步测试以将这些结果应用于实际情况。
