Process monitoring

Recent developments in sensor technologies for in situ monitoring have made it possible to obtain some insight into the state of the curing resin. Parameters are calculated from sensor measurements and analytical models developed in terms of the epoxy cure behaviour [31]. It is clear that it would be more beneficial if the 

Joshi S. The pultrusion process in polymer matrix composites. In Advani S, Hsiao K-T, editors. Manufacturing techniques for polymer matrix composites (PMCs). Cambridge (UK) Woodhead Publishing Limited 2012. 

Starr T. Pultrusion for engineers. Cambridge (UK) Woodhead Publishing Limited 2000. Black S. Pultruding costs out of aerospace parts. High-Performance Compos 2009. March 2009 Issue. 

Mouritz A. Introduction to aerospace materials. Cambridge (UK) Woodhead Publishing 

Mijovic J, Kenny M, Maffezzoli A, Trivisano A, Bellucci F, Nicolais F. The principles of dielectric measurements for in situ monitoring of composite processing. Compos Sci Technol 1993 49(3) 277-90. 

---

X-ray specimen image inter sifier tandem optics camera digital image processing monitor... 

BE- Intelligent equipment process monitoring for consistent finished product quality fIMPROQ) D. Farrington Bribsh Steel PLC... 

Process iron Process management Process monitoring... 

Process monitoring, both in the laboratory and on the production line, is an important appHcation of infrared spectrometry (see Process control). 

Diffusivities of various elements ate determined experimentally. Dopant profiles can be determined. The junction depth can be measured by chemically staining an angle-lapped sample with an HE/HNO mixture. The -type region of the junction stains darker than the n-ty e region. The sheet resistivity can also be measured using a four-point probe measurement. These two techniques ate used for process monitoring. 

Maintaining external awareness. Beyond understanding customer needs, a set process monitors external threats and opportunities from a variety of sources. 

The objective ia any analytical procedure is to determine the composition of the sample (speciation) and the amounts of different species present (quantification). Spectroscopic techniques can both identify and quantify ia a single measurement. A wide range of compounds can be detected with high specificity, even ia multicomponent mixtures. Many spectroscopic methods are noninvasive, involving no sample collection, pretreatment, or contamination (see Nondestructive evaluation). Because only optical access to the sample is needed, instmments can be remotely situated for environmental and process monitoring (see Analytical METHODS Process control). Spectroscopy provides rapid real-time results, and is easily adaptable to continuous long-term monitoring. Spectra also carry information on sample conditions such as temperature and pressure. 

Sample preparation is straightforward for a scattering process such as Raman spectroscopy. Sample containers can be of glass or quartz, which are weak Raman scatterers, and aqueous solutions pose no problems. Raman microprobes have a spatial resolution of - 1 //m, much better than the diffraction limit imposed on ir microscopes (213). Eiber-optic probes can be used in process monitoring (214). 

Sensors. One growth area for electronic ceramics is in sensor appHcations. Sensors (qv) are devices that transform nonelectrical inputs into electrical outputs, thus providing environmental feedback. Smart, or intelligent, sensors also allow for mechanisms such as self-diagnosis, recovery, and adjustment for process monitoring and control (see Process control). 

The second area, the implementation of a modem process monitoring and control system, is the most dramatic current appHcation of CAD/CAM technology to the chemical process industry. The state of the art is the use of computer graphics to display the process flow diagram for sections of the process, current operating conditions, and controUer-set points. The process operator can interact directly with the control algorithms through the... 

The process monitors and controllers typically also have the capabiUty for data logging, analysis, and display. This capabiUty has made on-line control of pilot plants, as well as commercial-scale processes, desirable. Pilot-plant appHcations for on-line control have been described (106), and the use of such systems for both monitoring and process diagnosis has been discussed (107). A number of commercially available process control programs that mn on microprocessors have been reviewed (108). Virtually all of them incorporate graphic display as an integral part of the interactive capabiUty of the program. 

The creation and analysis of process flow sheets has become much easier because of the availabihty of automated systems to draw and revise them. The goal of the use of the flow sheet as the input for process simulation and for process control is likely to be achieved reasonably soon. The use of interactive graphic displays for process monitoring and control is pervasive today. 

Ion-selective electrodes are available for the electro analysis of most small anions, eg, haUdes, sulfide, carbonate, nitrate, etc, and cations, eg, lithium, sodium, potassium, hydrogen, magnesium, calcium, etc, but having varying degrees of selectivity. The most successful uses of these electrodes involve process monitoring, eg, for pH, where precision beyond the unstable reference electrode s abiUty to deUver is not generally required, and for clinical apphcations, eg, sodium, potassium, chloride, and carbonate in blood, urine, and semm. 

In the area of consumer products, amperometric glucose sensors hold high potential. Industrially, process monitors for the manufacture of consumer chemicals are under development. However, replacement of defective reference electrodes, which in a laboratory environment may be trivial, may be prohibitively difficult m vivo or in an industrial process environment. 

A number of composition analyzers used for process monitoring and control require chemical conversion of one or more sample components preceding quantitative measurement. These reactions include... 

Periodic fault detection is readily done by analysts without extensive software support. Process monitoring such as the examination of the traces discussed above are one exam e. However, the number of measurements in a single set have such complex interactions that it is... 

Industrial Pollutant Monitoring for recordkeeping and report generation and Process Monitoring/Rcporting for process reports and other reports. Each requires 512K memory and lOMeg hard disk. 

The purpose of the control plan is to ensure that all process outputs will be in a state of control by providing process monitoring and control methods to control product and process characteristics. The control plan is covered in section 6 of the APQP manual. It consists of forms containing data for identifying process characteristics and helps to identify sources of variation in the inputs that cause product characteristics to vary. The APQP manual provides excellent guidance on the compilation and use of the control plan so no further guidance is given here. 

Controlled conditions include in-process monitoring and in-process inspection and test. All controls need a verification stage and a feedback loop. You cannot control production processes without performing some kind of verification. 

The action taken during process monitoring (see Part 2 Chapter 9) can be considered preventive action when corrections are made to the process ahead of occurring nonconformities. Hence Statistical Process Control is a technique which serves nonconformity prevention as well as detection. 

If we improve process monitoring and data logging, we ll be better equipped to track and predict variances in process operating conditions. 

A comprehensive program that includes predictive maintenance techniques to monitor and analyze critical machines, equipment, and systems in a typical plant. Techniques include vibration analysis, ultrasonics, thermography, tribology, process monitoring, visual inspection, and other non-destructive analysis methods. 

Monitoring and Measurement (customer feedback, internal audits, process monitoring, finished product release)... 

---