№63-11

Empirical definition of the shearing angle and chip-edge contact length when cutting

Yu. Kravchenko¹, V. Derbaba¹

¹Dnipro University of Technology, Dnipro, Ukraine

Coll.res.pap.nat.min.univ. 2020, 63:123-133

https://doi.org/10.33271/crpnmu/63.123

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ABSTRACT

Purpose. Simplification of shearing angle determination during chip formation and improving the determination of chip-edge contact length with the corresponding derivation of new calculation empirical formulas.

Methodology. The study is based on the use of analytical and probabilistic methods for calculating the shearing angle during chip formation, the shearing angle according to an empirical formula based on the cutting force components under a fine edge and a constant value of the friction-shift ratio, which adequately corresponds to the value of the most common formula based on the chip thickening ratio.

Results. The formulas for determining the shearing angle during chip formation are obtained. Value constancy of the friction-shift ratio for certain groups of steels has been determined. Compared to steel 45 more ductile austenitic steel 12Х18Н9Т has lower values of the friction-shift ratio. The length formula of the chip-edge contact based on the chip texture angle compared to the formula based on the chip thickening (shortening) ratio has a difference of more adequately accounting for the impact of the build-up forming phenomenon and increased metal deformation at negative rake angles. In the wake of cutting speed and rake angle rising there is a corresponding increase in the shearing angle and reduction in the contact length of chip with edge.

Scientific novelty. Functional dependances for determining the shearing angle during chip formation have been developed, which is achieved by introducing empirical dependences of the cutting force components under a fine edge on the operating and geometrical parameters of the cutting process, by establishing a constant value of the friction-shift ratio in the shear plane and corresponding formula derivation for determining the shearing angle, which excludes in each case time-consuming experiments to determine the shearing angle through the chip thickening ratio or holding the dynamometer test of the cutting force components.

Practical value. The use of empirical formulas for calculating the shearing angle and in the contact length of chip with edge on the basis of cutting force components under a fine edge makes it possible to exclude the experimental determination of the chip thickening ratio, and for account of “backward” calculation method of the cutting force components under a fine edge to refuse the time-consuming dynamometer test of the cutting force components in each case.

Key words: edge, chip formation angle, shearing angle, cutting forces, thickening ratio, cutting speed, rake angle.

References:

1. Zorev, N.N. (1956). Voprosy mekhaniki protsessa rezaniya metallov. Mashgiz.
2. Bobrov, V.F. (1975). Osnovy teorii rezaniya metalov. Mashinostroenie.
3. Mazur, M.P., Vnukov, M.P. & Dobroskok, V.L. (2010). Osnovy teorii rizannia metaliv (M.P. Mazura (Ed.)). Novyi svit– 2000.
4. Rozenberg, Yu.A. (2001). Metody analiticheskogo opredeleniya stepeni deformatsii metalla struzhki pri rezanii. Vestnik mashinostroeniya, 3, 34-38.
5. Loladze, T.N. (1982). Prochnost' i iznosostoykost' rezhushchego instrumenta. Mashinostroenie.
6. Kravchenko, Yu.G., Derbaba, V.A & Kryukova, N.V. (2015). K voprosu empiricheskogo opredeleniya napryazheniy i koeffitsientov treniya pri struzhkoobrazovanii.Rezanie i instrument v tekhnologicheskikh sistemakh: Mezhdunar. nauch.-tekhn. sb. – Khar'kov: NTU «KhPI», 85, 137 – 148.
7. Kravchenko, Yu. H., & Derbaba, V. A. (2020). Sposib vyznachennia kuta zsuvu pry struzhkoutvorenni (Patent No. 140418).
8. Armarego, I.D. & Braun, R.Kh. (1977). Obrabotka metallov rezaniem. Mashinostroenie.
9. Granovskiy, G.I. (1985). Rezanie metallov: uchebnik. Vyssh. shk.
10. Malyshev, V.I. (2011). Ocherki istorii nauki o rezanii materialov: monografiya. TGU.
11. Reznikov, N.I., Zharkov, I.G. & Zaytsev, V.M. (1960). Proizvoditel'naya obrabotka nerzhavaeyushchikh i zharoprochnykh materialov. Mashgiz.
12. Kosilova, A.G. & Meshcheryakov, R.K. (1985). Spravochnik tekhnologa – mashinostroitelya. V 2-kh tomakh. T2 – 4-e izd. Mashinostroenie.
13. Kravchenko, Yu.H., Derbaba, V.A. & Puhach,R.S. (2020). Sposib vyznachennia dovzhyny kontakta zalyvnoi struzhky z lezom (Patent No. 118302).
14. Patsera, S.T., Ruzhyn, P.O., Derbaba, V.A. & Korsun, V.Y. (2016). Alhorytm imitatsiino-statystychnoho doslidzhennia kontrolno-vymiriuvalnoi systemy ta yoho prohramna realizatsiia u Ni LabVIEW. Systemy obrobky informatsii. –  Kharkivskyi universytet Povitrianykh Syl im. I.Kozheduba., 6(143), 116-119.
15. Kravchenko, Y., Derbaba, V., & Smagin, D. (2020). Determination and relationship between shift and friction angles in chapter formation. Collection of Research Papers of the National Mining University, 61, 193–201.
    https://doi.org/10.33271/crpnmu/61.193
16. Zhuravel, O. Yu., Derbaba, V.A., Protsiv, V.V., & Patsera, S.T. (2019). Interrelation between Shearing Angles of External and Internal Friction During Chip Formation. Solid State Phenomena. Materials Properties and Technologies of Processing, (291), 193-203.
    https://doi.org/10.4028/www.scientific.net/SSP.291.193