Smart Manufacturing Processes and Equipment Program 

This program addresses measurement science and standards necessary to develop next generation smart manufacturing processes and equipment (self aware, self diagnosed, adaptive and optimized operations), which enable cost effective and agile manufacturing of complex, technology-intensive, innovative, customized products of the future. The program seeks to accomplish its objective through measurement science research and developing measurements and standards solutions in three thrust areas: (1) additive manufacturing, (2) smart machining, and (3) micro- and nano-manufacturing.

Objective: 

To develop and deploy advances in measurement science that will enable rapid, agile and cost-effective production of innovative, complex products through advanced manufacturing processes and equipment by the end of 2016.

What is the problem?  

Global economic and technological forces have created fundamental changes in U.S. manufacturing.  Rapidly changing global market demands and competitive environment create pressure on U.S. manufacturers to respond more quickly and efficiently with innovative products and processes^[1].  The future vision of U.S. manufacturing^[2] includes innovative, technology-intensive products and processes requiring intelligent manufacturing equipment; customization of manufactured products to meet individual customer needs; and 'point-of-use' manufacturing capabilities based on proximity to customers that are highly responsive to rapidly changing needs.  In a workshop^[3] organized by NIST recently, the following major industrial drivers were listed, among others: increasing pace of technological change; increasingly rapid product and process innovation; shorter time to market; continual push for higher quality, better performing customized products; increasing productivity and reducing costs; and highly efficient unit-of-one production.  Therefore, the ability to mass-customize products for a wide range of increasingly sophisticated and demanding customers and to produce them cost-effectively in any lot size will provide a competitive edge in the future.  In fact, according to a new report by The Boston Consulting Group, products more attractive to produce in the U.S. include those made in small lots and those that involve multiple design changes^[4].  Agile manufacturing processes, where the production is achieved by means of programmable action to create parts out of bulk or powder material with minimum specialized tooling, are therefore critical enablers for achieving U.S. competitive advantage. 

As one aspect of agile manufacturing, micro-nano-manufacturing also has potential high impact across a broad number of future manufacturing industries^[5].  The same report states that manufacturers need design models, standards, and in-situ measurements in order to increase yield and reduce material waste in micro-nano-manufacturing.  Considering the market for micro-nano products is expected to grow to $16-24 billion by 2020, solving these measurement science problems is urgently needed.

To address these challenges, measurement science is lacking to rapidly evaluate fundamental process characteristics and specify optimal process parameters, to evaluate and improve the performance of next generation manufacturing equipment, to improve quality of complex, high-value manufactured products, and to enable micro- and nano-scale agile manufacturing.

Why is it hard to solve?  

Manufacturing processes are very complex interactions of workpiece material properties, tool material properties, as well as mechanical and thermal loading of these components. Scientific understanding requires multi-disciplinary approaches and sophisticated measurement methods and instruments.  Similarly, rigorous characterization, measurement and control of manufacturing equipment, which consists of precisely interacting subsystems, are highly complex and costly.  In order to rapidly respond to changes in design, material and functionality of products, the operation of these complex systems, interacting with each other, have to be optimized rapidly and production must start without extensive period of operator adjustments.  Multi-disciplinary measurement science capabilities are needed to capture the system complexities and interactions in real manufacturing environments such that these processes and equipment can be modeled accurately.  Such robust predictive models are then used in process and equipment optimization eliminating the need for lengthy and costly adjustment prior to production.

How is it solved today, and by whom?  

Some U.S. companies have made strategic decisions to gain and retain specific manufacturing capabilities for their high-value, high-technology content products and processes, thus protecting competitive advantage.  For example big aerospace companies spend significant resources and efforts to learn how to process new non-conventional materials, such as super alloys, and keep the production of key components in house.  However, for any advances in material technologies, they have to go through similarly large expenses to learn about processing these new materials.  Furthermore, when they eventually subcontract some of these components to small and medium size second and third tier suppliers, there is a significant knowledge gap and this gap has to be filled with trial-and-error type learning processes.

Some other U.S. companies facing this problem choose to outsource their manufacturing operations to locations where these optimizations are done by many low cost engineers.  As an example, Apple has 700,000 manufacturing contract workers in China making iPods, iPhones and iPads.  The biggest challenge facing Apple that prevents them manufacturing in the U.S. is finding "mid-level manufacturing engineers in the factory who are constantly tweaking and making sure the operations are functioning effectively^[6]."  Smart manufacturing processes and equipment will overcome this problem such that constant tweaking will be achieved by machines incorporating relevant knowledge and real-time sensing about the process and adapting to changing conditions accordingly.

Why NIST?   

This program is closely aligned with the EL mission to promote U.S. innovation and industrial competitiveness in technology-intensive manufacturing by anticipating and meeting the measurement science and standards needs of the U.S. manufacturing industry.  The program is structured around the EL vision to be the source for creating critical solution-enabling measurement science and for critical technical contributions underpinning emerging standards that will be used by the U.S. manufacturing industry.  The program has several unique features that distinguish it from manufacturing research conducted in industry and academia: 1) emphasis on baseline performance metrics, metrology, and standards that can be applied to a broad class of measurement and manufacturing technology challenges, 2) effective use of NIST's demonstrated diverse interdisciplinary expertise, sustained commitment, and neutrality that are essential for the development of harmonized and unbiased national and international standards needed by broad sectors of industry.  In short, NIST has the necessary expertise, program focus, and statutory mandate to address the high-priority measurement science challenges in smart manufacturing processes and equipment most needed by U.S. industry.

What is the new technical idea?  

The new idea to accomplish agile and rapid manufacturing of complex customized products is to develop smart machines and processes, where most critical decisions and optimization is carried out by machines without significant operator intervention.  Such smart machines and processes will have the following characteristics:

• Self aware
• Adaptive and optimized
• Self diagnosed

Self awareness of machines and processes will require rigorous assessment of their performance.  Adaptive and optimized operation will be achieved through robust modeling and simulation and control.  Self diagnostic capability will be achieved by pervasive real-time sensing and monitoring to provide the equipment and process controllers with up-to-date status and conditions to ensure the correct manufacture of products without unscheduled down time.

The measurement methods, instruments, algorithms as well as knowledge and data exchange protocols and standards enabling self awareness, self diagnosis and optimization of processes and equipment will be developed and applied in each of the thrust areas within the program.

Why can we succeed now?  

There have been significant technological advances in machine controllers enabling execution of sophisticated control algorithms, in instruments enabling performance measurements, and in sensors and imaging systems to enable investigation of process phenomena with more accuracy and resolution.  Furthermore, in case of additive manufacturing, there is a ground swell of interest by U.S. manufacturing industry to improve the capability of this technology as evidenced by the recent initiation of an ASTM standards committee and the Additive Manufacturing Consortium.  By leveraging industrial experience and knowledge it will be more feasible to develop better process models, performance evaluation methods, and product quality metrics.  The program staff has access to most modern manufacturing equipment, including 5-axis machine tools, an ultra-precision diamond turning machine, and a brand new metal-based laser sintering machine to conduct experimental studies. 

What is the research plan?  

The program focuses on the processes and equipment at the workstation level, which consists of the machine tool and its peripherals that convert powder or bulk material into finished parts using agile processes that can be controlled by software programmable actions.  The complexity of products that are in consideration is associated with either: geometry, material, size, tolerance, number of parts and functions.  Within this broad scope, the program seeks to accomplish its objectives by focusing on three thrust areas: (1) additive manufacturing, (2) smart machining, and (3) micro- and nano-manufacturing.  These thrust areas were selected because machining is by far the most basic manufacturing process enabling other manufacturing processes, and additive manufacturing and micro- and nano-manufacturing are two new areas of manufacturing with potential to revolutionize manufacturing in the U.S.

Additive manufacturing (AM) is a key enabler for agile manufacturing providing fast response to changes in market demand and efficient and local production of specialized products directly from electronic communication of designs and design changes.  Industry observers project the market for AM will grow to $7 billion by 2020^[7].  It is predicted that biological and medical applications could make this market even larger.  AM is expected to contribute to competitiveness in the quality of American designs, time to market for new designs, and is considered as enabling technology for new industries.  Therefore, there is significant interest and focus on AM, including attention at the highest levels of corporate management and the federal government. On the other hand, AM is lacking the measurement science infrastructure to make it a strong alternative to other more established manufacturing processes.  Processes and powder material are developed by the machine vendors without any means of quantifying their performance and thus any clear path for improvements.  Therefore, the program, focusing on only metal-based additive processes, will investigate measurement science challenges related to AM equipment, processes, materials as well as AM systems integration and optimization.  Measurement methods and instruments will be developed to understand the fundamental process characteristics driving the related performance metrics and standards.  Performance evaluation methods will be developed for AM machines so that commercially available machines can be compared and selected by the users for optimum utilization.  The system integration efforts will seek to provide methods to integrate in-process measurement tools so that the process can be adaptively controlled to produce the parts with more and more stringent form and functional tolerances.  In parallel to these efforts, measurements and standards related to properties of powder metals used in AM as well as bulk metal properties produced by AM will be investigated to develop relevant standards for end users to confidently pick and choose their suppliers.

In the smart machining (SM) thrust, the program will seek to develop and integrate the measurement science and relevant technologies enabling smart machining.  Since many of today's high technology products use advanced, non-conventional materials for improved efficiency and reliability (corrosion resistance, high temperature operations, etc), the program focuses on machining of non-conventional materials, such as titanium alloys, inconel, composites, etc.  Working with a consortium of stakeholders, the program will identify high priority materials to be investigated.  Machining process metrology using such materials will be demonstrated and relevant process parameters will be correlated to the measured process characteristics.  The measurement data will be used to validate physics-based models to improve the robustness of these models such that they can be easily integrated with optimization algorithms for rapid decision making on the workstation level.  On the other hand, self awareness of smart machines dictates that the machine tool performance be quantified for any given task, involving complex motion of cutting tool with respect to the workpiece, and be available on the machine for any machine level optimization.  To integrate machine and process performance knowledge, data specifications and IT aspects of knowledge representation will also be investigated.  Such integration is targeted either within STEP-NC environment or within a commercially available Computer Aided Manufacturing (CAM) software package.  Finally, in order to self diagnose and eliminate any non-scheduled down time of machines, measurement science for continuous real-time monitoring of machines and processes will also be investigated.  The vast knowledge base related to general condition monitoring of industrial equipment will be used to identify and implement effective methods to machine tools and machining processes.

In the micro- and nano-manufacturing (MNM) thrust area, the program focuses on the challenges associated with manufacturing of miniaturized products, devices, and miniaturized features on larger products.  The size scale of interest is from nanometers to tens of micrometers, therefore the research activities address measurement science challenges related to manufacturing of a broad range of manufactured products including nanoelectromechanical systems (NEMS), complex micro optics, and micro mechanical systems.  The cross-cutting challenge in both micro- and nano-scales manufacturing is the need for measurement methods with adequately low uncertainties that can be incorporated in the manufacturing environment for deterministic control of the manufacturing process.  Due to size limitations and high bandwidth requirements, the measurement methods have to utilize non-contact instruments.  The interactions of the instruments with the manufacturing equipment and the product have to be well characterized through modeling, uncertainty analyses and rigorous tests.  This same approach will be used in the projects addressing both micro- and nano-scale manufacturing.  In addition, since this thrust area is still an emerging area, a key strategy of the program will be to maintain continuous and extensive interactions with groups of stakeholders to identify changing needs and priorities and to adapt the research directions accordingly.

What is the impact if successful?  

The primary outputs and outcomes of this program will consist of innovative measurement methods and new standards, advanced modeling and simulation tools, and other related measurement science needed for smart manufacturing processes and equipment.  Widespread implementation of program outcomes will lead to broad benefits for the U.S. economy, give U.S. manufacturers a significant technological edge in rapidly evolving markets and trigger the following future impacts:

• New era of U.S. manufacturing characterized by rapid production of innovative, customized, complex, high-value products
• Enhanced competitiveness of U.S. manufacturers in domestic and global markets, with increased innovation in products and production technologies
• New and better high-skill, high-technology manufacturing jobs based on U.S. manufacturers' use of smart manufacturing processes and equipment

Specific to the three thrusts of the program, the impact of program outputs and outcomes in additive manufacturing enable widespread adoption of AM processes by overcoming technology barriers identified in the 2009 Roadmap for Additive Manufacturing^[8]. 

The impacts in the smart machining area will be observed in widespread use of modeling and simulation along with on-machine measurements of processes and products to enable realization of autonomous smart machines that produce first and every subsequent part to specification without unscheduled delays. Manufacturers will also be able to use standard test methods to characterize new, non-conventional materials for modeling and optimization of machining, thus avoiding costly trial-and-error empirical practices.

The main impacts of the program in micro and nano manufacturing will cause a paradigm shift in application-specific imaging systems enabling large scale integration of optics and electronics, through manufacturing of complex optical components with nanometer level form tolerances simplifying the design of imaging systems.  The impacts will also be observed in widespread use of nanoelectromechanical systems for in-process and post-process measurements of nanomanufacturing processes and products enabling better process control to realize the significant growth projections of the micro- and nano-systems in the market.

What is the standards strategy? 

Sustained commitment and engagement with stakeholders is essential to develop consensus-based standards.  The SMPE program will allocate the resources necessary to maintain and initiate standards leadership for the U.S. and provide critical technical contributions for development of high-impact standards within its scope.

Top Standards Development Needs within the next five years to help achieve program objectives are identified as follows:

• Performance metrics and measurement methods for AM systems
• Standard metrics and assessment methods for AM materials
• Extension of international (ISO) machine tool performance standards to accommodate new methods to measure the performance of complex, five-axis machines
• Harmonization of national (ASME) and international (ISO) standards for representing machine and process capabilities and models
• Standard methods for measuring the performance of machine tools under loaded (machining) conditions
• Standard methods for measuring the performance of non-contact, on-machine metrology systems

Anticipated Impact: NIST measurement science research to develop measurement methods for AM systems and materials will be adopted by ASTM F42, Additive Manufacturing Technologies, as standards and best practice guidelines by 2015.  These standards and guidelines will be broadly used by the ever-expanding group of vendors and users of AM technology and AM products, particularly in medical and aerospace applications, to specify and optimize their use of AM technologies and products.  Taking into account the fact that AM is a new and developing technology area, widespread adoption of standards for performance metrics and measurement methods for AM systems by industry is expected by 2020. 

In the SM thrust area, NIST measurement science results will be adopted by ASME B5, Machine Tools and ISO TC39, Machine Tools and incorporated into relevant standards as the new test methods according to the timeline indicated in the Needs section above.  U.S. manufacturers of machined parts in automotive, aerospace, and heavy equipment industries, machine tool vendors, manufacturing software developers, third party service providers, system integrators, and the equipment maintenance industry will use these standards.  Widespread adoption by industry is expected by 2020.

In the MNM thrust area, NIST results will be incorporated into standards adopted by ASME B5and ISO TC39 by 2015.  The optics manufacturing industry will be a primary user of these standards.  The adoption by this industry and its suppliers is expected by 2018.

Broad industry sectors, including the automotive, aerospace, optics, heavy equipment, and medical device industries, will benefit from the standards resulting from this program. Companies will use these standards to make buy/sell decisions of manufacturing equipment, define and maintain process and equipment capabilities, conduct manufacturability analyses, allocate resources, and optimize process and equipment performance.

Current and Alternate Standards Strategy: In the AM area, substantial NIST experience in developing and structuring existing manufacturing standards will be leveraged to accelerate progress in AM standards.  The project results will be submitted as technical contributions to the ASTM F42 Committee.  The program staff will seek leadership roles in the working groups within ASTM F42.  Global competition requires that ISO standards should be consistent, compatible, and harmonized with U.S. national standards.  Therefore, program staff will also initiate interactions with the newly-established ISO committee on Additive Manufacturing (ISO TC261), primarily through the U.S. Technical Advisory Group.  Parallel efforts within both ASTM and ISO will be pursued to effectively influence international standards in this area. 

In the SM thrust area, the program already has a significant leadership role in both national and international standards.  NIST is a charter member of the ASME committees for machine tool performance testing (ASME B5 TC52) and related information technology standards (ASME B5 TC56).  NIST also serves as the Secretariat of the ISO sub-committee for developing standard test conditions for metal cutting machine tools (ISO TC39/SC2).  In this role, NIST has been instrumental in developing and maintaining more than 60 ISO standards related to machine tool performance testing (including turning, milling, drilling, grinding, and electro-discharge machining).  SMPE program research will introduce new standards and amendments to existing standards to address the needs of smart machine technologies.   

The SMPE program will also expand its active participation in standards committees in industrial automation, condition monitoring, process control, as well as in the MNM thrust area.  The program also recognizes that technical specifications, technical reports, and best practices guidelines published by Standards Development Organizations (SDOs) are effective outcomes that augment formal standards to further spread standards-based solutions to small and medium size manufacturers.  Therefore, where appropriate, the program will propose such documents to the relevant SDOs.

The SMPE program will also initiate industry consortia and working groups to jumpstart new standards and other alternative dissemination mechanisms in collaboration with stakeholders, including:

• Initiation of an industry consortium for machining non-conventional materials to disseminate NIST-developed robust methods for process performance
• Initiation of an industry working group in nanomanufacturing of NEMS to prioritize and review standards activities
• Initiation of an industry working group in closed-loop optics manufacturing for developing robust in-process standard measurement methods, as well as traceable reference artifacts

Fit to Criteria for Selecting Standards Development Involvement: The standards outlined above enable smart manufacturing, thus fall directly in line with the EL mission.  The needed manufacturing standards all require unique NIST measurement science capabilities.  The broad industry sectors identified above will benefit from these standards by implementing smart manufacturing technologies that improve responsiveness, machine utilization, and productivity.  Industry, government, and academia all play key roles in developing manufacturing standards and are involved in the above mentioned standards committees.  While the SMPE program will continue such collaborations in the development of new standards, NIST has a unique role in the standards development by providing unbiased expertise, critical measurement science research, as well as unique measurement facilities.

ASME and ASTM are the two primary SDOs that provide standards for manufacturing processes and equipment.  These organizations have long-standing track records as effective SDOs in this area.  The SMPE program will interact and collaborate with these organizations to result in efficient and effective development of needed standards.  Involvement with related ISO committees in parallel with the national SDOs will facilitate effective promotion of U.S. views and speed the adoption of them in the international arena, which is critical for global competitiveness of U.S. manufacturers.

Actual Impact: NIST technical contributions and standards leadership have recently resulted in:

• First ever international standard on testing the geometric accuracy of axes of rotation (ISO 230-7:2007)
• First ever international standards on testing the geometric accuracy of turning centers (ISO 13041-2:2008 and ISO 13041-3:2009)
• First ever international technical report for assessing machine tool vibrations (ISO/TR 230-8:2010)
• First ever international standard on testing a machine tool's measuring capability (for on-machine measurements of parts) (ISO 230-10:2011)

These standards are used by major U.S. manufacturers, including Boeing, Caterpillar, Pratt & Whitney, Hardinge, Precitech, Moore Tools, and their suppliers, to make machine tool buying/selling decisions, define equipment and process capabilities, and improve equipment and process performance.

In general, manufacturing process and equipment standards are not regulatory standards.  Therefore they are not typically adopted by any level of government in the U.S.  However, agencies involved with manufacturing (e.g., Defense Logistics Agency, Department of Energy, NASA) use these standards in their production and procurement activities.  The only regulatory use of these standards in the U.S. is in the context of export control regulations.  In the past, SMPE program staff have cooperated with designated U.S. government agencies (DoC, DoD, DoE, DoS) to define technology levels for export restrictions using international machine tool performance standards.  Export control regulations are revised periodically to align with new manufacturing standards, as well as to address new manufacturing processes and equipment.

How will knowledge transfer be achieved? 

The outputs and the outcomes generated by the program will be disseminated to customers and stakeholders through participation in standards committees, through participation in academic and industrial conferences, through focused workshops, roadmapping activities, seminars and webinars, as well as through journal articles, NISTIRs and conference proceedings.  For the areas where there are no active standard committees, stakeholder consortiums and consultative committees will be formed to enable intensive and continuous communications for effective exchange of research results and industry perspectives.

Outcomes:  

• Completed comprehensive literature study on metal-based additive processes and interacted with system users to identify the current state-of-the-art and challenges. Evaluated typical part errors and use of test parts to characterize the performance of additive manufacturing systems.
• Contributed to two key events for advancement of additive manufacturing capabilities establishing R&D directions and priorities:
• • Initiation of first-ever standards activities for additive manufacturing through the newly-formed ASTM F42 committee.
  • Collaborated with NSF, ONR, and industry experts contributing to the development of the 2009 Roadmap Additive Manufacturing that defined technology barriers and identified research opportunities through 2020.
• Demonstrated the successful operation of a newly developed in-situ measurement system for cutting tool dynamics ensuring efficient stable machining processes, greatly reducing time and expertise necessary to conduct such measurements by machine operators on the shop floor.
• Used the NIST Kolsky bar to characterize material properties at high strains and high strain rates of Ti64, provided by Kennametal, and two different types of stainless steel.
• Improved the uncertainty of measurement techniques for the temperature distribution of the cutting zone during orthogonal cutting, leading to more reliable validation of physics-based models of machining processes:
• • Characterized the size-of-source effects on measurement errors of the camera system, improving the accuracy of temperature measurement of thin features such as the shear band.
  • Improved uncertainty of temperature measurements of tool inserts by establishing that "pre-oxidizing" them keeps emissivity of the inserts constant during cutting experiments
  • Developed a technique to measure the temperature of cutting inserts using embedded thermocouples and performed experiments comparing thermal images of a cutting insert with temperatures measured by the thermocouples, achieving good agreement.
• Through leadership and technical contributions, the following machine tool performance standards were published:
• • Complete restructuring and updating of the basic ISO standard for defining and testing geometric accuracy of machine tools (ISO 230-1:2011) therefore achieving another milestone for harmonizing US and international standards for machine tool performance testing.
  • First ever international standard on testing geometric accuracy of axes of rotation (ISO 230-7:2007)
  • First ever international standards on testing geometric accuracy of turning centers (ISO 13041-2:2008 and ISO 13041-3:2009)
  • First ever international technical report assessing machine tool vibrations (ISO/TR 230-8:2010)
  • First ever international standard on testing machine tool's measuring capability (for on-machine measurements of parts) (ISO 230-10:2011)
• Successfully designed, fabricated, and characterized a prototype MEMS scanning tunneling microscopy (STM) scanner with an embedded displacement sensor. The achievable scan rate is greater than 3 kHz, which is at least ten times faster than conventional STM.  
• Developed a custom near-field scanning optical microscope (NSOM) for the measurement of out-of-plane NEMS motion with spatial resolution in several times better than a far-field optical microscope.
• Provided displacement measurements of RF NEMS for a major U.S. manufacturer of RF components to determine the relationship between mechanical and electrical modes.

The project activities associated with the SMPE program provide significant NIST/EL visibility within the manufacturing community due to their continuous interactions with stakeholders and timely delivery of critical technical solutions.  Examples of such recognition include membership in Industry Advisory Boards of Smart Machine Platform Initiative (SMPI), Coalition for Manufacturing Technology Infrastructure (CMTI)  and MTConnect Institute; membership in Board of Directors of North American Manufacturing Research Institute (NAMRI) and American Society for Precision Engineering (ASPE); various leadership roles in the standards committees including ASME B5 (Machine tools), ISO TC39 (Machine tools) as well as growing leadership role in ASTM F42 (Additive manufacturing); leadership roles in organizing 11^th CIRP conference on modeling of machining operations (2008), 3^rd International Conference on Micromanufacturing (2008), annual SME Micromanufacturing conferences (2008-2010), 9^th International conference on machine metrology (2009), ASME Symposium on "Advances in micro-scale manufacturing and metrology systems" (2010), NIST Advanced Manufacturing Workshop (2009), and NIST Extreme Manufacturing Workshop (2011).  Furthermore, the researchers of SMPE program have received various awards over the last several years including DoC Silver Medal (2006), NIST Bronze Medal (2008), Best Poster runner-up in NIST Sigma Xi postdoctoral poster presentation (2009), NAMRI/SME Outstanding Paper award (2009) as well as Certificates of Appreciation for dedicated service to ASME Codes and Standards (2009).

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[1] "Understanding Changes in U.S. Manufacturing," Report prepared for the DoC Working Group on Manufacturing, Economics and Statistics Administration, June 10, 2009.

[2] L. Rhoades, "The transformation of Manufacturing in the 21^st Century," The Bridge: National Academy of Engineering, Vol. 35, no. 1, 2005.

[3] "Summary of the NIST Extreme Manufacturing Workshop," Report prepared by IDA Science and Technology Policy Institute, March 29, 2011.

[4] "Small makes it big," Cutting Tool Engineering, vol. 63, no. 6, June 2011.

[5] "Manufacturing Trends 2010," Report by Strategic Business Insights, March 2010.

[6] Manufacturing News, vol. 18, no. 4, March 8, 2011.

[7] "Manufacturing Trends 2010," Report by Strategic Business Insights, March 2010.

[8] http://www.wohlersassociates.com/roadmap2009.pdf