Statistics and Time Series Analyses of BTA Deep Hole Drilling

BTA 1 deep hole drilling is a method for producing precision bores with high length to diameter ratios. The long and slender tools feature low torsional and bending stiffness. This may lead to undesirable dynamic disturbances of the machining process usually classified as either chatter vibration or spiralling. Prediction and identification of the causes of these process failures is important for stabilizing the manufacturing process, thereby reducing tool wear and risk of workpiece damage, optimizing the surface quality and minimizing defects of shape of the bores. Statistical process planning yields efficient descriptions of the relations between the process parameters and the quality of the bores. This method excels at being economic regarding the use of the restricted resources and the gain of information about the basic process behavior. Online time series recorded during the deep drilling process allow an interpretation of the dynamics of the manufacturing process. BTA deep hole drilling shows linear as well as nonlinear phenomena. Especially the interpretation of the nonlinear transition phase between stable machining and chatter is relevant for an early prediction of unstable process behavior. Keyword: Machining Technology, BTA Deep Hole Drilling, Process Dynamics, Time Series Analysis 1 (Boring and Trepanning Association) cutting inserts guiding pads Fig. 1. The BTA boring head