Forces and hole quality in drilling

Abstract

Drilling is one of the most commonly used machining processes in various industries such as automotive, Aircraft and aerospace, dies/molds, home appliance, medical and electronic equipment industries. Due to the increasing competitiveness in the market, cycle times of the drilling processes must be decreased. Moreover, tight geometric tolerance requirements in designs demand that drilled hole precision must be increased in production. in this research, A new mathematical model based on the mechanics and dynamics of the drilling process is developed for the prediction of cutting forces and hole quality. a new method is also proposed in order to obtain cutting coefficients directly from a set of relatively simple calibration tests. the model is able to simulate the cutting forces for various cutting conditions in the process planning stage. in the structural dynamics module, measured frequency response functions of the spindle and tool system are integrated into the model in order to obtain drilled hole profiles. therefore, in addition to predicting the forces, the new model allows the determination and visualization of drilled hole profiles in 3D and to select parameters properly under the manufacturing and tolerance constraints. an extensive number of experiments is performed to validate the theoretical model outputs with the measured forces and CMM hole profiles. It is observed that model predictions agree with the force and CMM measurements. Some of the typical calibration and validation results are presented in this paper.