Powder-based additive manufacturing (AM) technologies have been evaluated for use in different fields of application (aerospace, medical, etc.). Ideally, AM parts should be at least equivalent, or preferably better quality than conventionally produced parts. Manufacturing defects and their effects on the quality and performance of AM parts are a currently a major concern. It is essential to understand the defect types, their generation mechanisms, and the detection methodologies for mechanical properties evaluation and quality control. We consider the various types of microstructural features or defects, their generation mechanisms, their effect on bulk properties and the capability of existing characterisation methodologies for powder based AM parts in this work. Methods of in-situ non-destructive evaluation and the influence of defects on mechanical properties and design considerations are also reviewed. Together, these provide a framework to understand the relevant machine and material parameters, optimise the process and production, and select appropriate characterisation methods.Abstract: Powder-based additive manufacturing (AM) technologies have been evaluated for use in different fields of application (aerospace, medical, etc.). Ideally, AM parts should be at least equivalent, or preferably better quality than conventionally produced parts. Manufacturing defects and their effects on the quality and performance of AM parts are a currently a major concern. It is essential to understand the defect types, their generation mechanisms, and the detection methodologies for mechanical properties evaluation and quality control. We consider the various types of microstructural features or defects, their generation mechanisms, their effect on bulk properties and the capability of existing characterisation methodologies for powder based AM parts in this work. Methods of in-situ non-destructive evaluation and the influence of defects on mechanical properties and design considerations are also reviewed. Together, these provide a framework to understand the relevant machine and material parameters, optimise the process and production, and select appropriate characterisation methods.Reference to this paper should be made as follows: Taheri, H., Shoaib, M.R.M., Koester, L., Bigelow, T.A., Collins, P.C. and Bond, L.J. (2017) 'Powder-based additive manufacturing -a review of types of defects, generation mechanisms, detection, property evaluation and metrology', Int. Institute of Aviation Technology conducting research on UAVs and designing and printing 3D parts for UAVs. His research interest areas include engineering mechanics, additive manufacturing and non-destructive testing.Lucas W. Koester received his PhD from the University of Nebraska at Lincoln studying wave propagation and scattering in polycrystalline media. His current and past research interests include wave propagation in polycrystalline media, defect scattering, and modelling with emphasis on additive manufacturing processes and materials.Powder-based additive...

3D printing (3DP) is one of the modern approaches in the field of manufacturing. Although this process has been known for a fair amount of time, only the recent developments have revealed its novel and true potential for applications in different manufacturing sectors. Textile, one of the basic human requirements, does more than just fulfilling the fundamental necessity of covering our body. Integrating 3DP technology in textiles has broadened the horizon of the textile world.This review explores the historical background as well as state-of-the-art developments in 3DP related to textiles and fashion. Basic ideas about fundamental textile substrates, various 3DP technologies related to textiles, different printing devices and tools, materials used as print inks, direct printing of 3D objects on various textile substrates, fabrication techniques of 3D printed textile structures, different process parameters and their impacts, tests and standards, benefits and limitations are the contents of the discussions throughout this paper. It also highlights the future aspects concerning the further implementation of 3DP technology in the textile industry.Overall, the paper draws a picture with an intention to ascertain the undeniable promise of 3DP, despite having some drawbacks, to enrich the future of the textile and fashion industry with an aim to motivate future designers and scientists towards further exploration within this field of knowledge.

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