METEX - AN EXPERT SYSTEM FOR MACHINING PLANNING

Optimal selection of process parameters is an important problem faced by most process planners and NC programmers. Computerized systems and mathematical models are available in literature for machining parameter selection. These systems are usually constructed with compiled handbook data. The machining process is non-linear and exhibits piecewise behaviour within different cutting ranges. If this piecewise behaviour can adequately be represented in machinability parameter selection systems, more insightful selection of cutting conditions can be achieved. The present paper provides a comprehensive survey of existing literature on machinability parameter selection systems, followed by a literature-based analysis of the anomalies of machining and the process and material effects in machining. A justification of expert systems for qualitative modelling is provided. A prototype system (METEX) for machining parameter selection is then discussed. This system uses production (IF-THEN) rules to qualify machining at various cutting conditions. To begin, it provides the user with a set of nominal parameters, and then it gives the user a choice to change these parameters. The system then provides the user with the information about the process at these (changed) conditions, in terms of tool behaviour and active wear mechanisms. Hence, the user can make decisions based on the situation at hand to select cutting parameters. Only a simple prototype consultation system is presented and further extension is required for shop-floor implementation.