Development Of Machining Simulator With Error And Surface Roughness Display

Abstract

In today’s fast growing and competitive world, the machining industries use CNC machines for accuracy, speed , repeatability and flexibility. The cost of these machines is very high. As these are computer operated using very complex , large programs for controlling the tool motion, which are generated using automatic programming tools, there is always an uncertainty of the results and motion of these machines. Therefore there is need for some prediction of the outcome of the machining on a CNC machine. In this work, a machining simulator is developed for a 3- axis lathe mill using OAC technology. The simulator visually displays the machining being done. It also calculates the error which comes between the actual machined part and required geometry, in STL format which was taken for the tool path generation. The error calculated is normal to the surface of the geometry. The simulator is based on “mow the grass” technique in which the workpiece is represented by radial grass for lathe mill CNC. The tool position is read from the toolpath file and intersection with grasses is calculated and the radius of grasses is constantly updated which generates an animation of machining environment. The error is measured normal to the direction of machined surface from which conditions like undercutting and overcutting can be estimated. The average of error is also an indicative ‘Ra’ value of the machined surface. The machined surface , its error of scallop direction can be seen by OpenGL rendering with mouse based UI for zoom, pan and 3D rotate function with a color legend for knowing the magnitude of error.