OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 5 4 3 Influence of the shape of the toroidal flank surface on the cutting wedge angles and mechanical stresses along the drill cutting edge Petr Pivkin a, *, Artem Ershov b, Nikita Mironov c, Alexey Nadykto d Moscow State University of Technology “STANKIN”, 3a Vadkovski Lane., Moscow, 127055, Russian Federation a https://orcid.org/0000-0002-7547-4652, PMPivkin@gmail.com; b https://orcid.org/0000-0003-3966-7032, a.ershov@stankin.ru; c https://orcid.org/0009-0002-4205-6996, dzr1380im@gmail.com; d https://orcid.org/0000-0003-3652-7421, a.nadykto@stankin.ru Obrabotka metallov - Metal Working and Material Science Journal homepage: http://journals.nstu.ru/obrabotka_metallov Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science. 2023 vol. 25 no. 4 pp. 151–166 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2023-25.4-151-166 ART I CLE I NFO Article history: Received: 01 September 2023 Revised: 18 September 2023 Accepted: 27 September 2023 Available online: 15 December 2023 Keywords: Drill Toroidal flank surface Cutting wedge FEM Funding This project has received funding from the Russian Science Foundation (Project No. 23-29-00999, https://rscf. ru/project/23-29-00999/). The authors carried out research on the equipment of the Center of collective use of MSTU “STANKIN” (agreement No. 075-15-2021-695, 26/07/2021). ABSTRACT Introduction. Drilling holes with standard tolerance varying from IT8 to IT12 is widely used in industrial production. However, at present time, there are neither comprehensive studies, nor scientifically justified recommendations for the rational choice of the geometry of the cutting part of drills with a toroidal flank surface. Therefore, the computer-aided design (CAD) of new drill designs with a toroidal flank surface and finite element modeling (FEM) of the stressed state of its cutting part are important tasks. The purpose of the work is reducing both the range of change in the rake angle and the wedge angle of the cutting wedge along the cutting edge from the periphery to the center and the equivalent stresses in the cutting wedge. In this paper we investigate changes in the rake and wedge angles of the cutting wedge depending on the radius of the generatrix line of the toroidal flank surface as well as changes in equivalent stresses in the cutting wedge, which depend on changes in the radius of the generatrix line of the toroidal flank surface. The research methods include the fundamentals of the theory of cutting, CAD methods, and the FEM, which was applied in this work to new drill designs. Results and discussion. It is found that the range of changes in the rake angle and the wedge angle of the cutting wedge of the drill decreases compared to the standard design with decreasing radius of the generatrix line of the flank surface. A CAD system for drills with a toroidal flank surface is developed. As a result, the range of changes in the rake angle along the cutting edge decreased by 86 % for a drill with a minimum radius of the generatrix line of the toroidal surface compared to that with the conical flank surface, the range of the wedge angle of the cutting wedge decreased by 56 %, and the maximum equivalent stresses decreased by 2.13 times. It is also important to note that in this case, the wedge angle is close to constant for half of the drill tooth. These indicators exceed those for existing designs of the twist drills that indicate the key achievement of this paper. For citation: Pivkin P.M., Ershov A.A., Mironov N.E., Nadykto A.B. Influence of the shape of the toroidal flank surface on the cutting wedge angles and mechanical stresses along the drill cutting edge. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2023, vol. 25, no. 4, pp. 151–166. DOI: 10.17212/1994-6309-2023-25.4-151-166. (In Russian). ______ * Corresponding author Pivkin Petr M., Ph.D. (Engineering), Associate Professor Moscow State University of Technology “STANKIN”, 3a Vadkovsky Lane, 127055, Moscow, Russian Federation Tel.: +7 (903) 231-66-80, e-mail: PMPivkin@gmail.com Introduction Hole drilling is widely used in most essential industries. The twist drill is most common drill design. The advantages of twist drills include good removal of chips from the hole being machined, simplicity of design and, therefore, low labor costs of sharpening and high positioning accuracy in the hole due to the presence of calibration tapes [1]. The main cutting edges of the drill are located on a conical cutting part with an angle of 2ϕ. Angle 2ϕ acts as a cutting edge angle and varies from 70° to 135° [2].
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