The effects of thermal distortions on the diameter and cylindricity of dry drilled holes

A model is developed to predict the effects of thermal distortion of the drill and workpiece on the diameter and cylindricity of dry drilled holes. Experiments using embedded thermocouples verify that the model predicts the flow of heat into the workpiece and into the drill reasonably well. The model predicts that thermal expansion of the drill is the dominant effect and leads to oversized holes with diameters that increase with depth. (C) 2001 Elsevier Science Ltd. All rights reserved.