Athulan Vijayaraghavan

Metrics for Sustainable Manufacturing

Proceedings of the 2008 International Manufacturing Science and Engineering Conference MSEC2008 October 7-10, 2008, Evanston, Illinois, USA Proceedings of The 2008 International Manufacturing Science And Engineering Conference MSEC2008 October 7-10, 2008, Evanston, Illinois, USA MSEC_ICM&P2008-72223 MSEC2008-72223 METRICS FOR SUSTAINABLE MANUFACTURING Corinne Reich-Weiser ∗ Athulan Vijayaraghavan David A Dornfeld Laboratory for Manufacturing and Sustainability Department of Mechanical Engineering University of California Berkeley, California 94720-1740 {corinne@me.berkeley.edu, athulan@berkeley.edu, dornfeld@berkeley.edu} ABSTRACT A sustainable manufacturing strategy requires metrics for decision making at all levels of the enterprise. In this paper, a methodology is developed for designing sustainable manufac- turing metrics given the specific concerns to be addressed. A top-down approach is suggested that follows the framework of goal and scope definition: (1) goal - what are the concerns ad- dressed and what is the appropriate metric type to achieve the goal (2) scope - what is the appropriate geographic and manu- facturing extent. In this methodology a distinction is made be- tween environmental cost metrics and sustainability metrics. Uti- lizing this methodology, metrics focused on energy use, global climate change, non-renewable resource consumption, and water consumption are developed. ments (LCA), (3) adjustment/optimization of the system to min- imize environmental impacts and cost based on the chosen met- rics and the LCA [1]. This paper focuses on the first of these goals, and discusses the development of appropriate metrics for industrial processes and manufacturing systems. Metric selec- tion and development is a critical component in a sustainable manufacturing strategy as it enables decision making on all as- pects of manufacturing from tool choice to system configuration. For the purposes of this paper “sustainability” is understood as the ability of an entity to “sustain” itself into the future without impacting the capacity of other entities in the system to sustain themselves. This definition involves consideration of three main drivers: economics, society, and the environment. The first of these, economics, has traditionally been the focus of the manu- facturing research community. Societal concerns have been ad- dressed by researchers as they relate to increased profit, however additional social metrics to be considered include poverty, gen- der equality, nutrition, child mortality, sanitation, health, educa- tion, housing, crime, and employment [2]. Aggregated indices that provide a broad value for “wellbeing” or “environmental sustainability” have also been developed [3]. While these social and aggregate metrics are valuable to make broad decisions, they may not allow for granular insight and decision making within the manufacturing enterprise. Introduction Innovative strategies are needed to achieve sustainable pro- cesses technologies and industrial systems. “Green” technolo- gies are often understood as those capable of meeting product de- sign requirements while minimizing environmental impact. Min- imizing impacts, however, is a necessary but not sufficient con- dition for a sustainability strategy. Three important components of a sustainable manufacturing strategy are: (1) selection and application of appropriate met- rics for measuring manufacturing sustainability, (2) completion of comprehensive, transparent, and repeatable life-cycle assess- ∗ Address all correspondence to this author. This paper specifically discusses metrics related to the en- vironment and environmental sustainability, although the proce- dure for metrics development is applicable across other areas as well. Environmental metrics are a useful starting point for dis- Downloaded From: http://proceedings.asmedigitalcollection.asme.org/ on 07/09/2014 Terms of Use: http://asme.org/terms Copyright c 2008 by ASME

Introduction to Green Manufacturing

This chapter has as its objective a basic introduction to the topic to set the stage for the rest of the book. It introduces first the importance of this topic now and then the motivation, basics, and definitions associated with green manufacturing and sustainability. It describes some of the drivers that are causing governments and industry to take steps to green their processes, machines, systems, and enterprises. A discussion about the distinction between green and sustainable is introduced with respect to incremental improvements, greening and achieving overall sustainability. Strategies for achieving green manufacturing are presented. Barriers and obstacles to greening manufacturing are presented along with examples from industrial practice.

Strategies for Burr Minimization and Cleanability in Aerospace and Automotive Manufacturing

The quality of machined components in the aerospace and automotive industries has become increasingly critical in the past years because of greater complexity of the workpieces, miniaturization, usage of new composite materials, and tighter tolerances. This trend has put continual pressure not only on improvements in machining operations, but also on the optimization of the cleanability of parts. The paper reviews recent work done in these areas at the University of California-Berkeley. This includes: Finite element modeling of burr formation in stacked drilling; development of drill geometries for burr minimization in curved-surface drilling; development of a enhanced drilling burr control chart; study of tool path planning in face-milling; and cleanability of components and cleanliness metrics.

Metrics for Green Manufacturing

This chapter looks at metrics for green manufacturing and sustainability. Relevant economic metrics are reviewed and for complete coverage of sustainability issues, social metrics are also surveyed. The challenges of quantitatively evaluating social concerns are illustrated by highlighting the multiple considerations that social metrics attempt to capture. The chapter then survey metrics that tie in multiple considerations, pulling together ecological, social, and economic metrics. To inform metrics development, methods for inventory and impact assessment are also reviewed. Finally, the chapter presents several approaches for metric development, which systematically build up the metric based on considerations of goal, scope, system boundary, planning horizon, and system drivers.

Enabling Technologies for Assuring Green Manufacturing

This chapter reviews various technologies applicable in characterizing the resource utilization of manufacturing processes. A review of sensors to measure and quantitatively characterize the various flows involved in manufacturing processes and machines is first presented. Given the complexity of managing and parsing the sensor data, software tools are needed to automate data monitoring and the chapter presents a framework based on event stream processing to temporally analyze the energy consumption and operational data of machine tools and other manufacturing equipment. Finally, a case study that focuses on energy measurements and demonstrates the use of energy monitoring in reasoning over the performance of a manufacturing system is presented.

Closed-Loop Production Systems

This chapter discusses the closed-loop aspects of production systems in the context of green and sustainable manufacturing. Specifically, we consider the life cycle of production systems from design and construction through use, decommissioning, and recycling or repurposing. We discuss resource and economic efficiency and present a series of examples of life cycle analysis of manufacturing systems. We also describe how to design systems for reduced life cycle impact. Examples include comparisons of different machine tool systems, process parameter optimization, consumable utilization, plant services, and plant design.

Design and Fabrication of a Roller Imprinting Device for Microfluidic Device Manufacturing

Microfluidic devices are gaining popularity in a variety of applications, ranging from molecular biology to bio-defense. However, the widespread adoption of this technology is constrained by the lack of efficient and cost-effective manufacturing processes. This paper focuses on the roller imprinting process, which is being developed to rapidly and inexpensively fabricate micro-fluidic devices. In this process, a cylindrical roll with raised features on its surface creates imprints by rolling over a fixed workpiece substrate and mechanically deforming it. Roller imprinting aims to replace processes that were developed for laboratory scale prototyping which tend to not be scalable and have high equipment requirements and overheads. We discuss the limitations of PDMS soft lithography in large-scale manufacture of microfluidic devices. We also discuss the design, fabrication, and testing of a simple roller imprinting device. This imprinter has been developed based on the principles of precision machine design and is implemented using a three-axis machine tool for actuation and position measurement. A framework for the micromachining of precision imprint rolls is also presented.

Subdivision surfaces for procedural design of imprint rolls

We discuss the use of subdivision surfaces in the procedural design of imprint rolls for use in the roller imprinting process. Roller imprinting is being developed for the fabrication of microfluidic devices in polymer substrates. Imprint rolls are modeled using Catmull-Clark subdivision surfaces, and are procedurally designed based on feedback from finite-element simulations of the imprinting process. Microfluidic devices exhibit repeating patterns, and can be modeled using a small set of unique entities (or tiles). Imprint rolls are also modeled as a sum of tiles, and rolls are designed by studying the imprinting behavior of clusters of tiles corresponding to the repeating patterns seen in the device. This approach reduces the roll complexity and analysis time. The rolls need to be described in a sufficiently flexible format for the tile-based analysis to be effective. Conventional model representations are too cumbersome for piecewise iterative refinement as they require the manipulation of a large number of variables to modify surface features while preserving continuity. Subdivision surfaces, on the other hand, are naturally continuous and can be modified by manipulating a small number of variables. The ability to apply rule-based, arbitrary refinement on subdivision surfaces makes them especially suitable. The procedural modeling methodology and the subdivision design representation enable the integrated design, analysis, and manufacturing of imprint rolls, and has proven effective in decreasing the design-to-manufacture time of novel microfluidic technology.