An Industrial System for Estimation of Workpiece Height in WEDM

The wire electrical-discharge machining process (WEDM) is a widely-used technology which can achieve the requirements needed by industry, such complex geometries and precision. Cutting process control in WEDM becomes essential in terms of surface finish and dimensional tolerances. When a cut is made in a variable workpiece thickness, the process becomes very unstable in the transition zone. The difference of energy related to the WEDM regime cannot be easily accommodated when changing to another thickness. In this work a study of the most important variables that take part in the process is presented. It has been found that the workpiece thickness determination can be accomplished from the analysis of the variable Gap error, which is built as a combination of Ionization time (Td) and Servo voltage (Servo). An industrial system has been developed to determine the workpiece thickness with less than 10% error in comparison with the nominal value of part thickness.