Innovations in Manufacturing for Sustainability

Dry and near-dry techniques have been developed for sustainability interventions in machining. These techniques not only take care of sustainability and make the machining green, but also improve productivity and surface quality. This chapter comprehensively discusses various important aspects of these green manufacturing techniques. It discusses the conventional cutting fluids, their ecological problems, recently developed green lubricants, and lubrication techniques and their applications. It also overt the latest development in oil-, aqueous-, and gas-based synthetic and semi-synthetic cutting fluids and their relative advantages and disadvantages toward green manufacturing. The environmental and health issues related to cutting fluids and the latest technologies to minimize the detrimental effects of cutting fluids on human and the environment have been discussed. Finally, the latest trends toward green manufacturing including dry machining, near-dry (i.e., minimum quantity lubrication (MQL)) machining, and nano-enhanced MQL machining are discussed. At the end, two MQL-based machining case studies utilizing vegetable-based cutting fluids have been presented to highlight the importance of advanced green manufacturing.

In the present industrial scenario, manufacturing has become the backbone for the growth of any country. The advancement in manufacturing technology and methodology adopted has led to industrial growth, but it has some adverse effects on environment as well on human being such as environmental pollution and production of poisonous gases. Therefore, it is essential to find a sustainable manufacturing solution which is eco-friendly, highly productive, and economical from all aspects for human being’s comfort and environment. Cryogenic machining is one of the best sustainable substitutes for conventional machining. Major defects due to high temperatures can be reduced because of excellent coolant properties of cryogenic materials which slowed down the heat generation at the interface of tool and workpiece. This chapter introduces cryogenic machining and sheds light on its various important aspects along with presenting its comparison with the other machining methods based on different material properties, viz. surface finish, cutting temperature, and tool life.

Electric discharge machining is a well-known advanced machining process extensively used for difficult-to-machine materials, microparts and precision engineering components for various biomedical, scientific and industrial applications. In spite of EDM’s special characteristics, this process suffers from major limitations as regards to sustainability. High specific energy consumption, hazardous emissions, operator health and safety risk, generation of toxic waste and sludge, etc., are the major issues. This chapter introduces EDM, highlights and discusses inherent sustainability issues, and suggests possible solutions. An experimental study based on the use of sustainable dielectrics is the main part of this chapter. The effects of EDM parameters on material removal rate, surface roughness, and other surface integrity characteristics under the influence of sustainable dielectric fluids are discussed. The chapter ends with the conclusions and possible avenues of future research.

Metal casting is one of the most energy-intensive manufacturing processes that have developed along the evolution of mankind. Although nowadays its scientific and technological aspects are well established, in the context of future resource scarcity and environmental pollution pressures, new studies appear necessary to describe the “foundry of the future” where energy and material efficiency are of great importance to guarantee competitiveness alongside environmental protection. In this chapter, both managerial and technical good practices aimed at implementing energy-efficient casting processes are presented alongside a few examples. The “Small is Beautiful” philosophy is presented as a systematic approach towards energy resilient manufacturing and, potentially, sustainability in the long term. Thus, this chapter aims at providing an overview of the different aspects comprising the state of the art in the industry and examples of research themes in academia about energy-efficient casting processes.

Additive manufacturing (AM) has taken off for a steadily fast development, as it enables design flexibility and capability of increasingly complex, highly personalized products with enhanced performance and functionality. More importantly, it is claimed to hold great potentials in improving sustainability. However, how to fulfill such potentials is weakly supported by the scattered research. To better outline, connect, and coordinate the efforts toward a sustainable future of additive manufacturing, a research framework with six successive parts is proposed. Fused Deposition Modeling (FDM) is a relatively mature and widely applied process. Considering its scale, the sustainability issues in FDM are first attended. To demonstrate how the proposed research framework is utilized, a life cycle energy analysis of FDM processes has been conducted, including filament production, FDM printing, post-processing, and auxiliary services. Three research projects are presented and performed with the guidance of research framework. The common motivation is to understand the energy characteristics, key influential factors, and energy-saving opportunities in the FDM printing processes. The topics are (1) how the key parameters influence the process energy consumption; (2) the relation between energy consumption and surface roughness using different printers; and (3) how to minimize the overall printing time, correspondingly printing energy, of a multi-component complex part. It is hoped that with the proposed research framework, the future studies on sustainability in additive manufacturing can be consistent and comparable, and the data integration and cross-disciplinary data analysis can be facilitated.

Sustainable manufacturing considers environmental impact, energy utilization and economic impacts on process of creating product. Welding and processing is one of the most important elements of manufacturing field. Sustainability in welding and processing is the area of concern for today’s field of manufacturing. The present chapter elucidates components of sustainability for different welding and processing techniques. The discussions on energy saving, material waste, resources and parameters, environmental benefits and cost-saving capabilities of different welding processes are highlighted. Aforementioned sustainable interventions are addressed under various categories of welding and processing such as fusion arc welding, friction-based welding and processing, laser-based welding and processing, magnetic field-based processes and ultrasonic welding.

Titanium and its alloys are well known as difficult-to-machine materials due to low thermal conductivity and chemical adherent to cutting tools. Ti6Al4V is most widely used in a thin-wall structure application in the field of aerospace industry. Thin-wall machining encounters vibration and that furthermore increases fluctuations in cutting force. Select the type of machining process that generates sustainability in thin-wall machining is crucial to master. One of the innovations in conventional machining is to promote vegetable oils as the cutting fluids. These cutting fluids offer environmentally friendly cooling as well as lubrication to foster the cleaner production in the aerospace industry. Hence, the capable, sustainable cutting fluid has to be a future of the machining process. Minimum quantity lubrication (MQL) using coconut oil is recognised to be the green machining technique in milling titanium alloy. Coconut oils as nanofluids are attracting considerable attention due to good lubrication properties, non-toxic and biodegradable nature, and easy recycling. Therefore, it is a significant finding to observe the stability, dynamic behaviour, surface quality, and environmental aspects of cutting fluids in milling thin-walled Ti6Al4V. The findings reported in this chapter show that the use of coconut oil in the MQL system for thin-wall machining of Ti6Al4V is a promising innovation in the future of aerospace industries. At last, this chapter also sheds light on the treatment of exhausted cutting fluids.

Nowadays, the adoption of sustainable manufacturing practices is a prime requirement in manufacturing sector to comply with strict environmental regulations and sustain in global competitiveness scenario. Sustainability requirements have accelerated the research and development endeavours to find the advanced and/or sustainable substitutes of conventional manufacturing processes. This article reports important aspects of manufacturing of miniature gears by abrasive water jet machining with an aim to find a viable alternate of the conventional manufacturing processes. It also presents a comparative evaluation of abrasive water jet machining, wire-EDM, and hobbing considering various processes and product performance-based sustainability aspects such as geometric accuracy, surface finish, manufacturing cost and time, wastage, resource and energy efficiency, health and safety, and noise for manufacturing of miniature brass gears. Miniature gears made by these processes are of the same material (i.e. brass) and specifications with 0.7 mm module, 8.4 mm pitch circle diameter, and 5 mm thickness. In this study, based on some sustainability indicators such as manufacturing cost and time, energy and resource consumption, noise, wear and tear, wastage, and health and safety, the abrasive water jet machining process has secured the highest value of total process sustainability index of 82.5%; hence, it is identified as the most sustainable process for manufacturing of miniature gears.