Kolesnyk V. Technological support of quality when drilling cylindrical holes in "CFRP/titanium alloy stack"

Object of research: manufacturing process of drilling holes in CFRP/ titanium alloy stacks. Purpose: To decrease the technological cost of machining cylindrical holes in CFRP / titanium alloy stacks by improving the structure and parameters of the drilling process. Methods: planning model and full-scale experiments and processing their results were carried out on the basis of the theory of multivariate experiment. Investigation of the stability of technological process of drilling at different cutting conditions performed using probabilistic - statistical analysis of the scattering of the nominal size of the hole in the stack. Modeling of cutting process og CFRP performed by finite element method. Theoretical and practical results: developed an experimental method of temperature control at the cutting edge of the drill when drilling holes which made it possible to develope recommendations to ensure the accuracy and quality of holes in the CFRP / titanium alloy stacks with a single-pass technology of processing carbide drills, which reduced the technological cost of machining holes 30%. Novelty: for the first time on the basis of experimental data obtained by the mathematical model of cutting conditions influence on the cutting temperature, the axial force commensurate with the accuracy of the holes, delamination and surface roughness, which made it possible to perform the valuation of the quality of machining and take measures to improve the structure and technological parameters process drilling CFRP / titanium alloy stack. Results: The results of the dissertation implemented in the development of the technological process of manufacturing parts "Rukav" on the Company "Horizon 12", as well as in the educational process at the department of mechanical engineering, machines and tools of Sumy State University. Scope of application: machine building and aircraft building industry.