INVESTIGATIONS OF 3D PRINTED BIO-CERAMIC SCAFFOLDS AND IT’S LOGISTICS IMPLICATIONS

Abstract

Additive Manufacturing (AM), also known as 3D printing, is an advance manufacturing process. In this process, material is added in layer-by-layer fashion to fabricate a product opposite to subtractive and formative type of traditional manufacturing (TM) methods. There are different AM techniques including stereolithography (SLA), fused deposition modeling (FDM), selective laser sintering (SLS), and others. Each of them has its own benefits and limitations. Fused Deposition Modeling (FDM) is an extrusion-based AM technique. This technique uses polymers or their composites to fabricate products. The process has various advantages such as reduced waste, overall production time of a product, design flexibility, economic and easy in use etc. It is increasingly used in a wide range of industries including aerospace, automotive, healthcare, fashion, sports etc. AM has the potential to revolutionize the manufacturing industries and also their supply chains. It has potential to simplify the supply chain through decentralization, reducing transportation. AM can enable new business models such as digital inventory, where companies can produce parts on demand and eliminate the need for physical inventory. This leads to economic and sustainable supply chain. It allows fast and efficient production, which can reduce lead times. This means that companies can respond more quickly to changes in demand, reduce inventory levels, and improve overall efficiency. AM enables customization of products, improving customer satisfaction which help companies differentiate themselves in a crowded market. The present research work focused on preparation of a bio-composite for the fabrication of scaffold for bone tissue engineering. Assessment of barriers in AM adoption in medical supply chain, facility location allocation of 3D printers and sustainability analysis has been performed. In this regard, bio-composite filaments have been developed for FDM using Poly Lactic Acid (PLA) polymer and bio-ceramics (alumina and yttria stabilized zirconia). In order to validate the characteristics of developed bio-composite with two different bio-ceramics, thermal, physicochemical and mechanical characterization have been performed. Besides this, statistical models for mechanical strength (Ultimate Tensile Strength, Ultimate Compression Strength and Ultimate Flexural Strength) have been developed for FDM process. The experiments have been designed using Response Surface Methodology (RSM). The effect of input parameters has been investigated on output responses using Analysis of Variance (ANOVA). The influence of individual parameters on process outcomes and response surface plots for significant interactions have also been discussed. The statistical models have also been validated using experimental analysis. Additionally, porous structures having medical application have been printed using the optimized parameters and checked for dimensional accuracy, roughness compression strength and tribological behavior. 3D porous scaffolds have also been fabricated through FDM using developed bio-composite (PLA/alumina). The scaffolds have four different pore architectures and also coated with hydroxyapatite through dip coating technique. The physical, chemical and thermal characterization of PLA, PLA/alumina and coated scaffolds’ have been performed. Additionally, compression strength of different scaffolds has also been investigated. Besides this, the cytotoxicity test for material and other biological test have been performed to check the biocompatibility of the material and its geometry. The impact of AM on supply chain has been investigated through identifying the barriers in AM adoption for medical sector supply chain. The key barriers have been selected from previous studies through literature survey. The impact of different barriers upon each other have been analyzed with the help of experts. The interrelationship and ranking of barriers have been investigated using integrated approach of Interpretive Structural Modeling (ISM) and Analytic Network Process (ANP) methodologies. Also, managerial implications of the barriers have been discussed. Besides this, facility location allocation of 3D printing machine has been discussed for Uttarakhand state. The optimum number of locations and their allocations have been identified with minimum cost (fixed and variable transportation cost) objective function and coverage distance constraints. The sensitivity of the output has also been investigated for variable demand and capacity of the hub. Additionally, the sustainability analysis (economic, environmental and social) from the lifecycle perspective of a medical scaffold has been performed for AM and compared with TM route. The sustainability index for both the routes have also been evaluated through entropy weight method.