In this paper gun drill is considered as flexible continuous beam loaded with eccentrically applied cutting force. Most authors modeled drill shank using the reduced single degree of freedom system. The comprehensive review of present state of deep hole drilling modeling was given in. The same mechanism emerges not only in drilling, but in milling, boring etc. And it requires that time-delayed terms in model equations should be taken into account. The regenerative mechanism is the main source of chatter vibrations.

Therefore, it is important to predict in advance regimes with chatter vibrations. Excessive vibrations are detrimental to finish surface quality and may damage the tool. Due to low flexural stiffness of gun drill shank lateral vibrations of high magnitude could be excited during the machining. Optimal drill performance in gundrilling is achieved when the combination of the cutting speed, feed rate, tool geometry, carbide grade, and coolant parameters are selected properly depending upon the work material, deep-hole tool machine conditions, and the quality requirements to the drilled holes. The method is widely applied in machining small deep holes as it provides a good straightness and high quality of machined surface due to its self-guiding action. Gun drill has asymmetrical single edge tool design with long straight tube of asymmetrical cross-section with a typical reachable diameter range of 0.5 mm up to 40 mm and length-to-diameter- ratios up to L/ D = 400 (in special applications even L/ D = 900 ). Gundrilling is the mostly used method of deep small hole machining. This efficient process is widely used in the automotive industry to drill deep holes in cylinder heads, crankshafts, fuel pump housings, turbine blades and etc. The axial force and torque increased with the increase in cutting speed and feed rate.Long straight holes are usually produced by means of a special drilling tool.

The experiment data had shown that the relative error between the calculated values and the experimental The feasibility of the model was verified by experiments and the influence of cutting parameters on the axial force and torque was analyzed. Reasonably according to the theoretical analysis. In the meanwhile, the torque calculation was simplified

The eccentricity at the bottom of the drill groove was taken into account in the integral area of the cutting edge. The model coefficients were modified under various cutting conditions and the integral area of the cutting edge was enlarged. Referencing special energy model, a new gun drill mechanics model was established and the influence of the cutting parameters on axial force and torque was based on 15-5PH solid solution stainless steel through theoretical analysis and cutting tests.

Gun drill cutting parameters