Manufacturing engineering or manufacturing process are the steps through which raw materials are transformed into a final product. The manufacturing process begins with the product design, and materials specification from which the product is made. These materials are then modified through manufacturing processes to become the required part. Learn how to control process variation, including methods to design experiments that capture process behavior and understand means to control variability.

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Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

The industries in the IOF operate in an environment of global competition. For these suppliers of raw materials and semifinished goods, quality is a requirement, rather than a differentiator. Successful companies are able to manufacture high-quality products at the lowest possible cost. In this cost-constrained business environment, in-house process control groups are becoming smaller or even being eliminated. Hence, the industries are becoming increasingly dependent on suppliers of process control systems, even for ongoing optimization. At the same time, even though process control systems can give companies a technological advantage, new process control technologies will not be implemented unless they will have an immediate effect on current operations.

The development of improved process control technologies depends on cooperative efforts by multidisciplinary teams. The capabilities required to develop and implement new process control technologies vary significantly depending on the specific process science involved and on the maturity of the technology. Success depends on the integration of several technologies, which may include the following:

• process control science and engineering
• computer science and software engineering
• signal processing engineering
• measurement science
• process engineering
• manufacturing

Although significant efforts have been made to develop process control technologies and improve sensor technologies, most of the work has focused on the

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

manufacture of discrete parts. The technologies that can be used for large-batch and continuous processes are an area in which OIT can address the needs of important industries. This chapter presents the panel's recommended strategy for a process controls initiative by OIT to improve technologies for the materials processing industries represented in the IOF. The panel also suggests ways for OIT to coordinate research objectives and new technologies among the IOF sectors and with other programs.

Industry has shown a great deal of interest in the development of sensor and control technologies for a number of applications. Substantial government-supported programs are under way at many agencies. The U.S. Department of Defense has been working on environmental sensors to protect personnel and equipment, sensing and control technology to guide autonomous and remotely piloted systems, and intelligent process controls for component manufacturing. The National Institute for Standards and Technology has been developing standards for open-architecture controllers, robotics, and intelligent process controls for the manufacture of discrete parts. The National Science Foundation has been working on integrated sensors/controllers, intelligent controls, and condition monitoring systems. DOE has been investigating environmental sensing and advanced controls to improve process efficiency.

Regardless of the specific research objectives of these projects, the following general challenges are driving the development of sensors and manufacturing process control technologies:

• Variability and quality. Advanced sensors and process controls are necessary to monitor process variations so that high-quality operations can be maintained at lower cost.
• Environmental constraints. Innovative, robust sensory devices, including innovative sensor materials and coating technologies, are necessary to monitor process parameters and provide information in extreme high-temperature and chemically corrosive environments.
• Service. Process controllers are necessary to provide proactive maintenance capabilities, such as measurements of performance degradation, fault recovery, self-maintenance, and remote diagnostics.

STRATEGY FOR A PROCESS CONTROLS INITIATIVE

The panel recommends that OIT research be focused on the development of process sensors and control technologies to meet the needs of the IOF industries. In Chapter 2, the panel identified common industry needs for process sensing and manufacturing process controls based on common IOF process attributes. The

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

process attributes include (1) high processing volume and production rates, (2) large-batch or continuous processes, (3) commodity-grade products (low value per unit), (4) harsh processing environments, and (5) serial processing sequences (i.e., the output of one process is the feedstock for the next).

Common process sensing needs include

• measuring temperature profiles in harsh processing environments
• measuring chemical composition/stoichiometry in harsh processing environments
• measuring physical attributes at high line speeds and high temperatures
• monitoring combustion processes

Common needs for process controls include

• methodologies that enable in-situ-level process control
• hybrid process models
• plantwide or enterprise-level optimization
• tools for open-architecture applications
• adaptive control systems
• methods and diagnostic tools for condition-based maintenance of process equipment

To address these needs, the OIT program should include (1) a cross-cutting research initiative to develop fundamental technologies that address the common needs of IOF industries, (2) industry-specific (IOF) research to validate and implement advances in technology, and (3) an interagency initiative to coordinate plans and research objectives.

The panel believes the common needs for process controls and sensor technologies warrant a cross-cutting research and development initiative in this area. The panel recommends that OIT establish a research and development program that emphasizes the common needs of the IOF industries. Some of the research opportunities, identified in Chapter 3, are listed below:

• the development of sensor materials (including materials for the entire sensor system, which consists of sensor elements, packaging, leads, interconnects, and actuators) with significantly improved thermal and chemical resistance
• the compilation of a comprehensive database of candidate sensor material properties, including mechanical and physical properties; high-temperature properties; reactivity in chemical environments; and methods for deposition, formation, and patterning processing to accelerate the design and development cycle for the fabrication of new sensor systems

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

• the development of methods to measure temperatures accurately and reliably, including techniques, such as Johnson-noise thermometry, Raman-based thermal measurements, phosphor thermography, and self-verifying temperature sensors
• the development of low-cost, miniaturized, integrated analytical instruments that can provide direct, easy measurements of process chemistries for a wide range of process flow streams and conditions; techniques to be considered for process measurement and control include near-infrared spectroscopy, Raman spectroscopy, mass spectrometry, infrared spectroscopy, UV-visible spectroscopy, electrochemical spectroscopy, and acoustic spectroscopy
• the application of new processing science for fabricating and packaging integrated sensor/signal processing/actuation modules
• the development of measurement technologies that can rapidly characterize and evaluate physical properties for wide-sheet processes or web processes
• the application of wireless telecommunications technology to the development of advanced wireless sensors; areas for development include reliable wireless networks for process monitoring and control, remote power systems for wireless devices, and standardization of communication protocols, interfaces, and software
• the development of process control methodologies that can facilitate the transition from environmental-level to in-situ-level control methods; areas of interest include the effective use of process measurements, intelligent control algorithms, and the development of reliable process models
• the development of techniques that can integrate disparate process models
• plantwide optimization and controls, including automated data analysis techniques to identify key process variables, integration of control with maintenance operations, process control approaches to minimize energy consumption and environmental impact, large-scale nonlinear optimization algorithms, methods to deal with process model uncertainties, and dynamic data reconciliation for large-scale models
• the evaluation of open-architecture control systems for large-batch and continuous processes typical of IOF industries
• the development and implementation of learning and adaptive controls; particular topics for research include distributed adaptive/learning system architectures that are feasible for implementation by process industries, operator interfaces in semi-autonomous control systems, and system stability and safety

In addition to the common IOF industry needs, the organizational objectives of DOE and OIT—the reduction of raw material and energy consumption, improved labor and capital productivity, and the reduction of waste—must be considered. The panel recommends the following criteria, which are compatible with

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

DOE and OIT organizational objectives, as a basis for comparing and selecting projects for the cross-cutting program:

• potential for reducing the consumption of energy and raw materials and for reducing waste
• consistency with the technology road maps of the IOF industries
• potential benefits for more than one industrial sector
• potential for commercial application

One of the key challenges for OIT will be managing the cross-cutting program in a way that facilitates the development of specific performance goals based on the common needs of multiple industries. The panel recommends that an IOF coordination group be established, with representation of all of the IOF teams, to develop short-term and long-term goals and to monitor progress and results. Active participation by the IOF industry teams would help ensure that cross-cutting research programs remain responsive to industry needs. The group would review process attributes and control needs in each of the industries and establish a consensus on specific goals the cross-cutting program should pursue to benefit the maximum number of processes. Examples of process attributes that should be considered include (1) process environment (e.g., temperature and chemical exposure) to establish material requirements and performance ranges, (2) line speeds and sensitivity of the processes to variations to establish required system response times, and (3) the number of sensors and frequency of measurements to establish requirements for sensor fusion and data processing for the handling of large data sets.

In addition to establishing research goals, the IOF industry teams should monitor the progress and results of the cross-cutting program to speed the transition and scaling of new technology through validation and implementation programs. The panel recommends that OIT facilitate interaction between researchers and potential users within the IOF. These interactions could take the form of technical progress reviews and/or technology workshops to discuss technical developments and identify opportunities for validation and implementation.

All of the IOF vision documents identified manufacturing process controls and process monitoring sensors as important to the future success of their industries. The panel identified a cross-cutting initiative that would benefit multiple industries. However, the aspects of the required research and development that are unique to particular processes or conditions could be handled best by individual IOF groups, especially in the process development and implementation phases.

Industry-specific efforts could include the following:

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

• the development of road maps to identify technology needs and implementation plans
• participation in interactions with cross-cutting technology programs (e.g., technical workshops and progress reviews)
• the development and validation of process models related to specific key processes
• improved process models that can facilitate the transition from environment-level control schemes to in-situ-level controls
• the optimization of process control systems, especially supervisory controls and plantwide integration
• the validation and implementation of improved sensor technologies and process control systems for large-scale processes

Significant efforts related to sensors and process controls have been made by other agencies in the government—especially the National Institute for Standards and Technology, the U.S. Department of Defense, the National Science Foundation, and elsewhere in DOE. The final challenge to OIT will be to coordinate the cross-cutting and industry-specific aspects of the OIT program with other government-sponsored programs. The panel recommends that OIT program managers continue to lead the interagency and intra-agency coordination of progress in complementary technologies to avoid duplications. In addition to monitoring the complementary programs, the committee recommends that OIT collaborate with four programs that are particularly important to the success of the OIT program.

• National Institute for Standards and Technology program to develop standards for open-architecture systems; IOF industries should evaluate and validate system standards for large-batch and continuous operations
• National Science Foundation programs to improve process sensing and process modeling capabilities (e.g., the Measurement and Control Engineering Center at the University of Tennessee-Knoxville; the Center for Process Analytical Chemistry at the University of Washington; and the Center for Industrial Sensors and Measurements at Ohio State University); IOF industries should coordinate the implementation and application of process modeling and advanced sensor technologies
• U.S. Department of Defense research, especially at DARPA, to develop MEMS devices, fabrication processes, and applications; IOF industries should evaluate these devices for sensing/control of industrial processes
• U.S. Department of Defense (especially Army, Navy, and DARPA) programs to develop condition-based maintenance approaches; IOF industries should evaluate sensors and diagnostics developed to monitor processing equipment and machinery

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

Suggested Citation:'4 Recommendations.' National Research Council. 1998. Manufacturing Process Controls for the Industries of the Future. Washington, DC: The National Academies Press. doi: 10.17226/6258.

Next: A Workshop Agendas »

Basics of Process Control Systems

In a manufacturing setup, there will be different parameters for critical processes that have to be monitored. The real time values of these parameters will be fed to a central control system. These values are compared with the preset set-points through feedback systems and the necessary alerts are output on the display system, so that corrective action can be taken.

Representative process control system is one in which, a laser diode acts as the measuring device for detection of liquid/gas present in a given industrial environment.

The frequency signature of concerned material (liquid/gas) is then passed on to the receiver. It is then converted in digital form and picked by the processor.

The cost-performance trade off is to be balanced to implement application-specific peripherals for achieving the desired core performance.

Once the core is optimized for working with the desired peripherals, and speed, the rest of the system may be designed as per budget considerations.

PLC and DCS: The Heart of Process Controls

The primary devices that are used in a process control system are Programmable Logic Controllers better known as PLCs in short. PLCs are the best bets for controlling machines with several discrete devices such as motor starters, limit switches, and the likes of them, which are often involved in automation process like material handling, state machines, sequencing, status reports etc.

Distributed Control Systems, commonly abbreviated as DCS, are central control systems, which are good at controlling analog devices; thereby aiding in process control.

In a manufacturing setup, feedback from different sensors tendering to many processes are given to a bank of PLCs. Each process has a separate set of PLCs and the output of these which contain information regarding the status at the shop floor is given to the DCS. PLC is just a controller and DCS is a central controller with a MMI [Man Machine Interface]. Corrective controls are input to the DCS, which is given to the PLC and thereafter sent to the individual control devices.