Fused deposition modelling (FDM), one of the most commonly used additive manufacturing techniques in the industry, involves layer-by-layer deposition of melted material to create a 3D structure. The staircase and beading effect caused by the printing process and temperature variation cause delamination and poor surface finish in FDM-printed parts. This hinders the use of these specimens in various applications, which are then usually resolved using pre-processing and post-processing techniques. Higher surface finish in pre-processing is achieved by increasing the resolution, changing layer thickness and optimizing build orientation. However, this increases the processing time considerably. On the other hand, post-processing techniques involve different processes such as mechanical, chemical, thermal and hybrid methods but can affect the mechanical and structural properties of the printed components. This review paper analyses three different aspects in the area of improving the surface finish of FDM-printed parts. First, this article reviews the state-of-the-art attempts made to improve the surface finish of FDM-printed parts concentrated mainly on different vapour polishing techniques and their respective merits and demerits. Second, it focuses on the changes in mechanical properties before and after polishing. Finally, the paper explores the development in the 3D printing of thermosets and composite materials and their post-processing processes and process parameters.

Additive manufacturing (AM) or 3D printing has been playing a very important role in the manufacturing sector in recent decades. The AM basic process is meant to produce an object layer by layer and has many advantages that include the occurrence of only minimal production waste during production and easy manufacture of even the most geometrically complex materials. However, there are many challenging decision-making situations in the production of AM for its users, for example, the build chamber, material specification, technology types, and application requirements. This includes the choice of the best AM machine (AMM) from many AMM with slightly different features that are identical on the market, especially on a real-time basis. This research explored ways that AMM is to be selected using multi-criteria decision-making (MCDM) on a real-time basis. This includes the use of the MCDM fussy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to help select the most suitable fusion deposition modeling (FDM) for an Indian nongovernment organization (NGO) from nine different machines based on contemporary. Practice in this research paper, an Indian NGO is considered as a decision-maker in the choice of the best FDM machine based on nine common criteria because an NGO has prescribed nine different FDM machines and the NGO needs the help for the purchase of the suitable FDM to produce different fields of prototypes. The outcome of this research is to recommend a suitable FDM machine from the nine similar to slightly different features of FDM machines by the suggestion of the field experts (AM machine users). The contribution of this research is not only to enable the purchase of the suitable AM machine but also to reveal the various contemporary FDM machines and the general criteria to be considered in choosing them.

In the emerging modern technology of additive manufacturing, the need for optimization can be found in literature in many places. Additive manufacturing (AM) is making an object layer by layer directly from digital data. Previous works of literature have classified additive manufacturing processes into seven types. However, there is a lack of comprehensive review describing the optimization challenges and opportunities in the material extrusion process (polymer technology) and also the need for FDM polymer materials application in impeller making. In this review paper, a specific optimization method called multicriteria decision-making (MCDM) from the mathematical programming technique used in additive manufacturing polymer technology (AMPT) is discussed. The other topics such as different types of optimization techniques, applications of different MCDM tools and their applications in different fields including AM, and the optimization challenges and opportunities in AMPT particularly impeller application are discussed.

The temperature of Photovoltaic (PV) module rises by absorbed incident solar radiation and causes subsequent drop off in electrical efficiency. To overcome this ill effect, an appropriate material must be used to absorb the heat and maintain the temperature of PV module. The purpose of present study is to review and understand various cooling techniques used to enhance cooling and electrical performance. The emphasis was placed on design and operating parameters like absorber configuration, flow pattern, flow rates, climatic conditions, radiation intensity, wind speed, thermal conductivity, glazing, concentration on the electrical and thermal characteristics. The reviewed papers include theoretical analysis, computer simulation, solar simulator and on-field experiments. The study states that the proper selection and utilization of cooling technology, design and process parameters are the key elements in the solar photovoltaic (PV) system to achieve optimum performance.

In this modern world, 3D printing technology plays a very important role in the manufacturing sector. It can be found easily in recent decades, be the increasing use of 3D printing in many fields and including FDM [Fusion Deposition Modelling] technology. This research paper is for an Indian electrical switch product-based manufacturing MSME [Micro Small and Medium Enterprises] company, to select the optimum set of printing parameters of the FDM machine for producing a high-quality final product in less time. To this end, the fifteen pieces of ASTM D638 tensile specimen were fabricated with a modified cluster of fourteen printing parameters for ensuring the mechanical property with less production time by the results of fabrication time, tensile test, and microstructure analysis. Moreover, the Design of Experiments (DoE) has been used for the analysis of the tensile strength and FESEM (Field Emission Scanning Electron Microscope) equipment has been used for the analysis of microstructures. Finally, the optimum printing/process parameters have been suggested to the MSME Company based on the experimental results.

Urban freight sector in India witnesses the exponential usage of cargo bikes since 2011, for reaching its customers. Cargo bikes are used by e-retail firms for mobility in traffic dense roads. This research contributes to the sustainable development of e-commerce and it measures the economic, environmental and social efficiency of cargo bikes in e-retail firms using survey method. It also estimates the optimum volume of cargo bikes on city roads for effective and timely delivery. Data collected by video graphic study is analysed by a traffic simulation tool 'PTV Vissim'. Simulation results are validated with the real data. The findings of this research help to replace mini trucks with cargo bikes, which in turn minimizes the delivery time, carbon emission, and driver discomfort. The major implications of this research are: e-retail firms have to motivate its customers to prefer prepaid orders and delivering the goods at non-peak time to achieve sustainability.