A comprehensive methodology for manufacturing system evaluation and comparison

~culrnalof.Manufacturing SysternJ 111110 IZ/INO. 1

Cumulative Abstract Index

structure and related machlning operations is presented. ~ nents proposea technique represents a new and ~enerative method-

large computerized systems and the increasing application of aruficial intelligence. For the information management of these manufacturing environments, this means increasing amounts of data to manage, higher number of requests and a need for significantly higher reliability and availability. The presented model for an active and highly efficient information system targets the problems that arise from these trends. A distributed system of cooperatinl~, consistent, knowledge base sites is proposed that uses a sem,-intelligent mechanism to predict the user processes in timing and data needs, to plan and schedule the operation of the site, and to prel~aro the data before the retrieval request arrives. The prepared information is stored in object frames, ready for quick access by the user. The test runs of a prototype software exhibit the feasibility of the proposed model and show the potential for high efficiency, reliability, availability, and correct performance. Keywords: Information System, Hierarchical, Integrated, FrameBased CIM

ology for integrating CAD and CAM. Artificial intelligence techniques such as expert systems, languages, pattern recognition, and fiuite-state automata are applied in this research. Symbolic strings containing the design and machinlng attributes of components are analyzed using knowledge rules ~ syntactic pattern recognition techniques. Keywords: Pan Assignment, Cellular Manufacm~. ? Expert Systems, Integrated Design and Manufacturing, Artificial Intelligence

A Knowledge Based Syztemfor the SpecO~cationof Man~actur. inS Tolerances, S. Mam'vanusn,A. Lchthm, P. Egbelu, pp. 153-60 T~.'s paper describes a knowledge based system developed for specification of ISO fits for the manufacture of rotational mating components with interference, clearance and transition fit types. Either a shaft basis or hole basis system can be used for specification of tolerances. The knowledge base consists of various toleranceinformation, fit types, rules and procedures. The rulebase is based on ISO recommendations for standard fits and tolerances. Given basic information such as diameter, type of fit and achievable deviation, the rule oriented system for computer aided tolerancing (ROSCAT) provides the ISO fit that is best suited for the given manufacmrin8 conditions. Keywords: ISO Standards, Pits and Tolerances, Intedereuce Fit, Clearance Pit, Transition Pit, Rule.based, luference Mechanism, Constraint-directed Search, Forward Chaining, Backward Chaining

Parametric Simulationfor FlexibleAssembly Systems, M. Ketcham, J. Watt, pp. 115-25 This paper describes the manufacturing logic incorporated in a parametric simulation system called SIMBHD. SlMBED has been developed to represent the characteristics of flexible manufacturing/flexible assembly systems with multiple l~roducts and flexible parts routlngs. The core simulation model incorporates the logic necessary to represent four FMS/FAS subsystems: (I) assembly workstations, (2) product routing decisions, (3) inventory and inventory policies, and (4) material handling. The modular structure of the core model is mirrored in a simulation database and a highly structured spreadsheet-like interface. Using a parametric approach reduces simulation development time for evaluating system interactions in a FMS/FAS environment. Keywords: Flexible Manufacturing Systems, Flexible Assembly Systems, Parametric Simulation

1989~ Vol. 8/No. 3 A Comprehensive Methodolo~for Mam~acmrin& System Evaluation and Comparison, J. Troxler, L. Blank, pp. 175-83

Linguistic Modeling of Flexible Manufacturing Systems, K. Tam, pp. 127-37 Production feasibility, machine assignment, and machine failure in a flexible manufacturing system are studied from the perspective of formal language theory in this paper. Heterogeneous flexible flow line is introduced as the manufacturing system model. Finite state language is used to describe a flow llne in terms of all the possible operation sequences that it can carry out. Issues such as production feasibility, machine assignment, and robustness can be addressed, formulated, and solved as linguistic problems. The linguistic approach presented in this paper attempts to offer new persl~.~:tives and modeling methodology in the study of manufecturmg systems. ords: Linguistic Modeling, Parsing, Production Feasibility, • Assignment, Robustness

The implementation of manufactnrin8 technology in American industry has lagged the advances made in recent years. The absence of adequate analysis and justification methods is a fundamental problem in dealing with investment decisions of this scope and complexity. But even when the justification barrier is overcome, some problems remain, as evidenced by the failure of several installed flexible manufacturing systems to produce at a des/red level of out put, the preponderance of evidence in the Hterature and case studies suggests that justifying and tracking manufacturing systems is a complex task that requires consideration of many tangible and intangible decision factors. Previously developed methods usually focus on subsets of factors measured strictly in monetary-based terms. A comprehensive methodology that systematically identifies the relevant decision factors and incorporates them in a procedure to indicate the value of the Stem to the user is presented. rds: Justification, Manufacturing Systems, FMS, Costs, Methodology, Planning

Feature Based Expert Parts Assignment in Cellular Manufacturing, H. EiMarashy, pp. 139-52 This paper presents a new approach for on-going decision making need to assign parts to fexible manufacturing cells, in support of the dynamic dispatching and scheduling required for day-to-day operation. A feature based design description language (FDDL) and expert analyzer, synthesizer and recognizer have been developed to directly perform the automatic and dynamic assignment of parts to manufacturing cells from a feature based prototype modeling system. The assignment system is based upon knowledge of both the part design features and manufacturing processes. Feature based representation of corn-

Approximate Cost Estimatesfor Typical Turned Part~, G. Boothroyd, C. Reynolds, pp. 185-93 A model is derived for the cost of typical rotational components machined from a bar in a CNC turret lathe. It is found that for components having a finished volume greater than 20 cubic inches the work material costs contribute more than 80% to the total component cost. For smaller components, however, the

70