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The development of sustainable manufacturing solutions is gaining attention in the manufacturing sector due to increased awareness about climate change and the formulation of stricter environmental legislation. Sustainable manufacturing involves the development of solutions that are environmentally friendly and cost-effective at the same time. Considering the opportunities and limitations of metal subtractive and additive manufacturing approaches from a sustainability perspective, this study aims to compare the environmental impact and production costs associated with the manufacture of a marine propeller using pure subtractive CNC milling along with additive Wire arc additive manufacturing (WAAM) and Selective Laser Melting (SLM) approaches. Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) are used to quantify the environmental and economic impacts, respectively for each manufacturing approach. Based on the LCA and LCC models formulated, and the input data collected, the WAAM approach is observed to be the most environmentally and cost-efficient approach for the marine propeller analyzed. WAAM shows an environmental impact about 2.5 times and 3.4 times lower than pure CNC milling and SLM approaches, respectively mainly due to its better material and energy efficiencies. The effect of key variables on the environmental impact and production cost such as raw material, electricity, and post-processing parameters like a material allowance for finish machining and cutting velocity is also studied to suggest the parameters ensuring sustainable performance for a particular approach. WAAM is seen to be the most economical and ecological option for a post-processing material allowance under 4 mm and the finish machining velocities below 96 m/min. Additionally, an uncertainty assessment using the Monte Carlo analysis method is also performed to give a probabilistic range of environmental impacts and production costs considering the input data uncertainties for each approach. The methodology used in this study can be applied to other additive manufacturing processes. This study can be of potential help to AM practitioners in decision-making on selecting the most sustainable approach for manufacturing their products.

In many cities and their surrounding environments, materials are wasted and underutilized. As a result, waste and energy recovery can play a critical role. The concept of circularity can be applied to urban environments and their areas of influence in order to stimulate Urban Industrial Symbiosis (UIS). As such, it is vital for cities to have a robust and trustworthy information management infrastructure. A blockchain-based system can provide the accountability the UIS networks need to become traceable, transparent and unchangeable for all the parties involved. Similar to the benefits that blockchain can provide supply chain networks, UIS could benefit from blockchain as well. In this article, we look at blockchain and Smart Contracts as a way to benefit UIS, what they can be used for, what the goals and potential limitations for their implementation are, and how those goals and limitations might influence UIS. Finally, through the implementation of modular blockchain architecture, an UIS blockchain model based on smart contracts is proposed.

Over the past few decades, adoption of different Additive Manufacturing (AM) processes has gained momentum in the manufacturing industry. One such emerging AM process is wire-based directed energy deposition. Environmental impacts and costs are important criteria for adoption of any manufacturing process. Therefore, the aim of this paper is to evaluate the environmental and economic performance of Wire and Arc Additive Manufacturing (WAAM) using Life Cycle assessment (LCA) and Life Cycle Costing (LCC) methodologies. In this paper, an integrated methodology to conduct a cradle-to-gate LCA based on the guidelines of ISO 14044 and LCC based on IEC 60300–3–3 standards is proposed. A case study of a single steel wall manufactured by WAAM was analysed. The environmental impacts and production costs for wire-based directed energy deposition process were compared to laser powder bed fusion (LPBF) and Computer Numeric Control (CNC) milling processes. For the steel wall analysed, CNC milling was the most economical and ecological option followed by the wire-based directed energy deposition and LPBF. However, the performance of a process depends on product complexity and the manufacturing process’s material efficiency. Raw material production and labour were identified as major environmental hotspot and cost driver, respectively, in wire-based directed energy deposition. The methodology used in this paper can be extended to other manufacturing processes. The results of this study can help manufacturers in selecting manufacturing processes based on environmental impacts and production costs

The “Circular Car”, as a strategic concept, adopts a circular flow in the whole product lifecycle: reduction, recovery, repair, renovation, reuse, and recycling of all components. These processes are a part of the value chain, and the reason is to increase value and the circularity of materials. The goal of this paper is to develop a conceptual model that uses cars as a case study in order to support the development of a full circular car throughout the product lifecycle, i.e. from the drawing to the use of the vehicle that we know today, to make the companies more environmental, socially and economically responsible. Based on the literature review and interviews and questionnaires with the automotive industry’s stakeholders, a set of practices - designated by “circular practices” – that can be used by the automotive industry are identified and the relationships between them established by using the Interpretative Structural Modelling (ISM). The main results of this study make it possible to identify the practice “Development of alternatives to internal combustion engines” being at the top of the ISM hierarchy, which means that this practice is dependent on the other practices. In order to have the “Circular Car” concept implemented solutions as battery electric vehicles, plug-in hybrid electric vehicles, among others, need to be supported by the other “circular practices”.

In this paper a methodology was followed in order to support the decision-making of one industrial unit regarding its internal logistics system. The addressed factory was facing issues with their internal logistics approach. Some alternatives were pointed out and a proper total cost of ownership (TCO) analysis was developed. This analysis was taken in order to demonstrate the more cost-effective solution for the internal logistics system. This tool is more and more valued by the companies, due to their willing to reduce the costs that are associated with the way of doing business. Despite the proposal of the best choice for the internal logistics system of the enterprise, this study also intends to present some conclusions about the match between the nature of the industrial unit and the logistics systems that best fit the requirements of those.