Computer processing control, statistical

Manufacturing processes have been improved by use of on-line computer control and statistical process control leading to more uniform final products. Production methods now include inverse (water-in-oil) suspension polymerization, inverse emulsion polymerization, and continuous aqueous solution polymerization on moving belts. Conventional azo, peroxy, redox, and gamma-ray initiators are used in batch and continuous processes. Recent patents describe processes for preparing transparent and stable microlatexes by inverse microemulsion polymerization. New methods have also been described for reducing residual acrylamide monomer in finished products. 

QA = quahty assurance QC = quaUty control SQC = statistical quaUty control SPC = statistical process control CIM = computer-integrated manufacturing. 

While the single-loop PID controller is satisfactoiy in many process apphcations, it does not perform well for processes with slow dynamics, time delays, frequent disturbances, or multivariable interactions. We discuss several advanced control methods hereafter that can be implemented via computer control, namely feedforward control, cascade control, time-delay compensation, selective and override control, adaptive control, fuzzy logic control, and statistical process control. 

Use a statistical process control (SPC) computer software monitoring and control program to improve the record keeping and results trend analysis. 

Control System Included in this classification are Supervisory Control and Data Acquisition Systems (SCADA), Distributed Control Systems (DCS), Statistical Process Control systems (SPC), Programmable Logic Controllers (PLCs), intelligent electronic devices, and computer systems that control manufacturing equipment or receive data directly from manufacturing equipment PLCs. 

Rollo JL, Fauser BA. Computers in Total Quality Management Statistical process control to expedite stats. Arch Pathol Lab Med 1993 117 ... 

Blaivas (B4) described the use of an IBM-1710 process-control system, on-line to 20 AutoAnalyzers, in which the computer program included instructions for the acceptance or rejection of standard curves, and a series of checks for monitoring the acceptability of values obtained for control sera. Any results that failed to meet the requisite criteria were indicated within a few seconds of the charting of a peak by a message typed on an on-line typewriter. This system has the ability to include daily statistical assessments of the quality of results, but these possible additional control features were not listed in the description (B4). 

M Kano, S Hasebe, I Hashimoto, and H Ohno. Evolution of multivariate statistical process control Independent component analysis and external analysis. Comput. Chem. Engg., 28(6-7) 1157-1166, 2004. 

Up to the present time it has not been possible to demonstrate the ultimate reliability of characterizations based on random disturbances. However, the use of random disturbances offers great potential advantage in studying existing process control systems where upsets like step disturbances cannot be tolerated. Because of the extensive calculation required to reduce the random operating records to statistical-correlation functions, high speed digital computation is essential in this treatment. 

Westgard, J. O., and T. Groth. 1981. Design and evaluation of statistical control processes Application of a computer quality control simulator program. Clinical Chemistry 27 1536-1547. 

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