Designing and Redesigning Products, Processes, and Systems for a Helical Economy

The Circular Economy (CE) concept has promised to unlock trillions of dollars in business value while driving a significant reduction in the world’s resource consumption and anthropogenic emissions. However, CE mainly lives in ambiguity in the manufacturing domain because CE does not address the changes needed across all of the fundamental elements of manufacturing: products, processes, and systems. Conceptually, CE is grounded in the concept of closed-loop material flows that fit within ecological limits. This grounding translates into a steady state economy, a result that is not an option for the significant portion of the world living in poverty. Therefore, this paper proposes the Helical Economy (HE) concept as a novel extension to CE—one that allows for continued innovation and economic growth by leveraging an Internet of Things (IoT) infrastructure and by reimagining products, processes, and systems. This paper intends to be the conceptual overview and a framework for implementing Helical Economy in the manufacturing domain

Strategies for Value Creation Through Sustainable Manufacturing

Making the business case and establishing strategic directions for sustainable manufacturing requires a collaborative effort. Strategic capabilities that can help create sustainable value for all stakeholders must be identified. Technologies and methodologies to provide these capabilities for implementation must then be developed, through public-private partnerships. This paper presents major business imperatives and strategic capabilities necessary to enable value creation through sustainable manufacturing identified based on extensive engagement with business leaders and industry professionals as well as academic experts and government agency representatives. The paper also presents a future vision for sustainable products, processes and systems that can be derived from such capabilities

A Total Life Cycle Approach for Developing Predictive Design Methodologies to Optimize Product Performance

Sustainable products must be designed by considering how design decisions impact their total life cycle (TLC) sustainability content. Even more so important when designing products to incorporate the technological elements of sustainable manufacturing, the 6Rs (Reduce, Reuse, Recycle, Recover, Redesign and Remanufacture), to achieve Circular Economy (CE). This paper presents the preliminary work of an ongoing research project on developing a novel framework incorporating predictive models with TLC considerations. This unique approach develops and integrates models with associated risks, and optimizes for maximizing the sustainability benefits due to design decisions. Such predictive capability is extremely useful for process planning, where careful planning and optimization of process conditions would allow inducing favorable product performance and improved sustainability

Towards Developing Sustainable Reconfigurable Manufacturing Systems

This paper aims to examine the sustainable manufacturing performance of Reconfigurable Manufacturing Systems (RMSs) using existing sustainable manufacturing metrics. RMS has six key characteristics including modularity, integrability, customization, scalability, convertibility, and diagnosability. In this paper, ‘convertibility’ is quantified by considering configuration convertibility, machine convertibility, and material handling device convertibility from the RMS perspective. In addition, the performance of RMSs with different convertibility levels is also evaluated by using sustainable manufacturing metrics. A numerical example is used to demonstrate the computational approach. Results of the analysis are used to show how sustainable manufacturing performance of RMS changes as system convertibility varies. The findings show that RMS sustainable manufacturing performance can be improved by selecting a suitable level of convertibility

Parallel Design of a Product and Internet of Things (IoT) Architecture to Minimize the Cost of Utilizing Big Data (BD) for Sustainable Value Creation

Information has become today\u27s addictive currency; hence, companies are investing billions in the creation of Internet of Things (IoT) frameworks that gamble on finding trends that reveal sustainability and/or efficiency improvements. This approach to “Big Data” can lead to blind, astronomical costs. Therefore, this paper presents a counter approach aimed at minimizing the cost of utilizing “Big Data” for sustainable value creation. The proposed approach leverages domain/expert knowledge of the system in combination with a machine learning algorithm in order to limit the needed infrastructure and cost. A case study of the approach implemented in a consumer electronics company is also included

Analysis of Surface Integrity in Machining of AISI 304 Stainless Steel Under Various Cooling and Cutting Conditions

Recent studies have shown that machining under specific cooling and cutting conditions can be used to induce a nanocrystalline surface layer in the workspiece. This layer has beneficial properties, such as improved fatigue strength, wear resistance and tribological behavior. In machining, a promising approach for achieving grain refinement in the surface layer is the application of cryogenic cooling. The aim is to use the last step of the machining operation to induce the desired surface quality to save time-consuming and expensive post machining surface treatments. The material used in this study was AISI 304 stainless steel. This austenitic steel suffers from low yield strength that limits its technological applications. In this paper, liquid nitrogen (LN2) as cryogenic coolant, as well as minimum quantity lubrication (MQL), was applied and investigated. As a reference, conventional flood cooling was examined. Besides the cooling conditions, the feed rate was varied in four steps. A large rounded cutting edge radius and finishing cutting parameters were chosen to increase the mechanical load on the machined surface. The surface integrity was evaluated at both, the microstructural and the topographical levels. After turning experiments, a detailed analysis of the microstructure was carried out including the imaging of the surface layer and hardness measurements at varying depths within the machined layer. Along with microstructural investigations, different topological aspects, e.g., the surface roughness, were analyzed. It was shown that the resulting microstructure strongly depends on the cooling condition. This study also shows that it was possible to increase the micro hardness in the top surface layer significantly

Sustainable Living Factories for Next Generation Manufacturing

To be profitable and to generate sustainable value for all stakeholders, next generation manufacturers must develop capabilities to rapidly and economically respond to changing market needs while at the same time minimizing adverse impacts on the environment and benefiting society. 6R-based (Reduce, Reuse, Recycle, Recover, Redesign and Remanufacturing) sustainable manufacturing practices enable closed-loop and multi-life cycle material flow; they facilitate producing more sustainable products using manufacturing processes and systems that are more sustainable. Reconfigurable Manufacturing Systems (RMS) and its characteristics of scalability, convertibility, diagnosability, customization, modularity and integrability have emerged as a basis for living factories for next generation manufacturing that can significantly enhance the system sustainability by quickly adjusting system configuration and production processes to meet the market needs, and maintain the system values for generations of products. This paper examines the significance of developing such next generation manufacturing systems as the basis for futuristic sustainable living factories by adapting, integrating and implementing the RMS characteristics with the principles of sustainable manufacturing to achieve value creation for all stakeholders

Sustainable Production Through Balancing Trade-Offs Among Three Metrics in Flow Shop Scheduling

In sustainable manufacturing, inconsistencies exist among objectives defined in triple-bottom-lines (TBL) of economy, society, and environment. Analogously, inconsistencies exist in flow shop scheduling among three objectives of minimizing total completion time (TCT), maximum completion time (MCT), and completion time variance (CTV), respectively. For continuous functions, the probability is zero to achieve the objectives at their optimal values, so is it at their worst values. Therefore, with inconsistencies among individual objectives of discrete functions, it is more meaningful and feasible to seek a solution with high probabilities that system performance varies within the control limits. We propose a trade-off balancing scheme for sustainable production in flow shop scheduling as the guidance of decision making. We model trade-offs (TO) as a function of TCT, MCT, and CTV, based on which we achieve stable performance on min(TO). Minimizing trade-offs provides a meaningful compromise among inconsistent objectives, by driving the system performance towards a point with minimum deviations from the ideal but infeasible optima. Statistical process control (SPC) analyses show that trade-off balancing provides a better control over individual objectives in terms of average, standard deviation, Cp and Cpk compared to those of single objective optimizations. Moreover, results of case studies show that trade-off balancing not only provides a stable control over individual objectives, but also leads to the highest probability for outputs within the specification limits. We also propose a flow shop scheduling sustainability index (F S S I). The results show that trade-off balancing provides the most sustainable solutions compared to those of the single objective optimizations

Experimental Study on Surface Integrity of Cryogenically Machined Ti-6Al-4V Alloy for Biomedical Devices

Titanium and its alloys are widely used in the biomedical sector. In this field, titanium and its alloys are the material of choice for biomedical devices such as hip and knee replacements. Usually, a Total Hip Replacement (THR) is based on four components, made out of different materials due to the material properties associated with the functional performance. One approach to lower the overall manufacturing costs and enhance the reliability of THR’s is to manufacture the prosthesis out of one material. The titanium alloy Ti-6Al-4V is, therefore, feasible as it exhibits better osseous integration compared to other metallic materials used as orthopedic devices. The sole use of Ti-6Al-4V alloy requires improvements of surface integrity (SI) and characteristics that are sensitive to SI. One possible way to improve the tribological properties of the THR and the biocompatibility of Ti-6Al-4V alloy is to deliberately decrease the material grain size in the surface layer from the micron scale (\u3e 1 µm) to the region of nano-sized grains (\u3c 100 nm). The objective of this paper is to study and prove the formation of nano-sized grains within the surface as well as the characterization of surface integrity when machining Ti-6Al-4V alloy. Therefore, different cryogenic cooling strategies are used where liquid nitrogen (LN2) is applied to the flank and rake face, and just to the flank face respectively. To compare the effect of cryogenic machining, conventional flood cooling was applied as third cooling strategy. As cutting tool, a roughing tool, having a large cutting edge radius, was used, since severe plastic deformation (SPD) has shown to be capable to produce nano-sized grains in the surface. The results showed, that cryogenic machining using a large cutting edge radius tool is able to decrease the materials grain size to the region of nano-sized grains

Rotary Friction Welding Versus Fusion Butt Welding of Plastic Pipes – Feasibility and Energy Perspective

According to the Plastics Pipe Institute, butt fusion is the most widely used method for joining lengths of PE pipe and pipe to PE fittings “by heat fusion” (https://plasticpipe.org/pdf/chapter09.pdf). However, butt-welding is not energy-cognizant from the point of view of a phase-change fabrication method. This is because the source of heating is external (heater plate). The initial heating and subsequent maintenance at relatively high temperature (above 200 C for welding of high-density polyethylene pipe) is energy intensive. Rotary friction welding, on the other hand focuses the energy where and when as needed because it uses electric motor to generate mechanical (spinning) motion that is converted to heat. This work will make the case for friction heating as energy efficient. An initial feasibility study will also be introduced to demonstrate that the resulting welded pipe joints may be of comparable quality to those produced by butt fusion and to virgin PE material