Machine Vision System for Correlating Wire Electrode Status and Machined Surface in WEDM of AlSi₃N₄ MMC'S

The technological developments in various sectors and requirement of complex shapes in manufacturing industries, the need for advanced materials has increased. Composite materials are one such advanced material. The most widely used composite materials is metal matrix composite. Conventional machining of these materials causes serious tool wear due to the presence of abrasive reinforcing particles and thus reduced tool life. Wire electrical discharge machining (WEDM) is quite successful for machining of metal matrix composites. Wire Electrical Discharge machining (WEDM) is a specialized thermal machining process capable of accurately machining parts of hard materials with complex shapes. One of the main research fields in WEDM is related to the improvement of the process productivity by avoiding wire breakage. Recently, vision systems are being exploited for such application mainly due to their high resolution, reliability and ease of automatic processing of data. Machine vision system is the technology used to provide image based automatic inspection and analysis for such applications as automatic inspection, process control and robot guidance in industries. This paper presents machine vision system, capable of providing wire electrode status and workpiece surface texture information in Wire electric discharge machining of aluminium silicon nitride (AlSi3N4) composite material. The images of wire electrode and machined surface specimens were acquired using the machine vision system. From the analysis, a good correlation between the wire electrode and corresponding surface image was found. It is expected that these results would support further to establish a criteria for wire replacement in WEDM operation. (paper)