An automatic system designed for the monitoring of cutting tools using real-time control concepts and fuzzy approaches

Cutting tools are essential and costly components in a flexible machining cell (FMC). Tool assignment and tool exchange control are vital managerial decision functions for a group of CNC machines in an FMC. A well-designed tool control system should include the abilities of tool scheduling and tool information monitoring in an automatic fashion. A Tool Monitoring System (TMS) as presented in this paper is a large-scale computer software tool, which consists of an off-line part and tool assignment model and a real-time tool information monitoring mechanism. The underlying principle of the system is based upon the approach of simultaneous scheduling of parts and tools. In the part and tool scheduling processes, part geometry, work progress specifications and tool availability are the key factors to be considered in calculating a part priority weight for the design of tool assignment orders. Fuzzy logic approaches are employed to determine the weight for a batch of jobs with multiple parts. The case study shows that the aggregated criteria can all be considered using the fuzzy model. An immediate action can be taken to overcome shop-floor problems by the tool information monitoring mechanism.