Vol. 24 No. 4 2022 3 EDITORIAL COUNCIL EDITORIAL BOARD EDITOR-IN-CHIEF: Anatoliy A. Bataev, D.Sc. (Engineering), Professor, Rector, Novosibirsk State Technical University, Novosibirsk, Russian Federation DEPUTIES EDITOR-IN-CHIEF: Vladimir V. Ivancivsky, D.Sc. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Vadim Y. Skeeba, Ph.D. (Engineering), Associate Professor, Department of Industrial Machinery Design, Novosibirsk State Technical University, Novosibirsk, Russian Federation Editor of the English translation: Elena A. Lozhkina, Ph.D. (Engineering), Department of Material Science in Mechanical Engineering, Novosibirsk State Technical University, Novosibirsk, Russian Federation The journal is issued since 1999 Publication frequency – 4 numbers a year Data on the journal are published in «Ulrich's Periodical Directory» Journal “Obrabotka Metallov” (“Metal Working and Material Science”) has been Indexed in Clarivate Analytics Services. We sincerely happy to announce that Journal “Obrabotka Metallov” (“Metal Working and Material Science”), ISSN 1994-6309 / E-ISSN 2541-819X is selected for coverage in Clarivate Analytics (formerly Thomson Reuters) products and services started from July 10, 2017. Beginning with No. 1 (74) 2017, this publication will be indexed and abstracted in: Emerging Sources Citation Index. Journal “Obrabotka Metallov” (“Metal Working & Material Science”) has entered into an electronic licensing relationship with EBSCO Publishing, the world's leading aggregator of full text journals, magazines and eBooks. The full text of JOURNAL can be found in the EBSCOhost™ databases. Novosibirsk State Technical University, Prospekt K. Marksa, 20, Novosibirsk, 630073, Russia Tel.: +7 (383) 346-17-75 http://journals.nstu.ru/obrabotka_metallov E-mail: metal_working@mail.ru; metal_working@corp.nstu.ru
OBRABOTKAMETALLOV Vol. 24 No. 4 2022 4 EDITORIAL COUNCIL EDITORIAL COUNCIL CHAIRMAN: Nikolai V. Pustovoy, D.Sc. (Engineering), Professor, President, Novosibirsk State Technical University, Novosibirsk, Russian Federation MEMBERS: The Federative Republic of Brazil: Alberto Moreira Jorge Junior, Dr.-Ing., Full Professor; Federal University of São Carlos, São Carlos The Federal Republic of Germany: Moniko Greif, Dr.-Ing., Professor, Hochschule RheinMain University of Applied Sciences, Russelsheim Florian Nürnberger, Dr.-Ing., Chief Engineer and Head of the Department “Technology of Materials”, Leibniz Universität Hannover, Garbsen; Thomas Hassel, Dr.-Ing., Head of Underwater Technology Center Hanover, Leibniz Universität Hannover, Garbsen The Spain: Andrey L. Chuvilin, Ph.D. (Physics and Mathematics), Ikerbasque Research Professor, Head of Electron Microscopy Laboratory “CIC nanoGUNE”, San Sebastian The Republic of Belarus: Fyodor I. Panteleenko, D.Sc. (Engineering), Professor, First Vice-Rector, Corresponding Member of National Academy of Sciences of Belarus, Belarusian National Technical University, Minsk The Ukraine: Sergiy V. Kovalevskyy, D.Sc. (Engineering), Professor, Vice Rector for Research and Academic Affairs, Donbass State Engineering Academy, Kramatorsk The Russian Federation: Vladimir G. Atapin, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Victor P. Balkov, Deputy general director, Research and Development Tooling Institute “VNIIINSTRUMENT”, Moscow; Vladimir A. Bataev, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Vladimir G. Burov, D.Sc. (Engineering), Professor, Novosibirsk State Technical University, Novosibirsk; Aleksandr N. Gerasenko, Director, Scientifi c and Production company “Mashservispribor”, Novosibirsk; Sergey V. Kirsanov, D.Sc. (Engineering), Professor, National Research Tomsk Polytechnic University, Tomsk; Aleksandr N. Korotkov, D.Sc. (Engineering), Professor, Kuzbass State Technical University, Kemerovo; Evgeniy A. Kudryashov, D.Sc. (Engineering), Professor, Southwest State University, Kursk; Dmitry V. Lobanov, D.Sc. (Engineering), Associate Professor, I.N. Ulianov Chuvash State University, Cheboksary; Aleksey V. Makarov, D.Sc. (Engineering), Corresponding Member of RAS, Head of division, Head of laboratory (Laboratory of Mechanical Properties) M.N. Miheev Institute of Metal Physics, Russian Academy of Sciences (Ural Branch), Yekaterinburg; Aleksandr G. Ovcharenko, D.Sc. (Engineering), Professor, Biysk Technological Institute, Biysk; Yuriy N. Saraev, D.Sc. (Engineering), Professor, Institute of Strength Physics and Materials Science, Russian Academy of Sciences (Siberian Branch), Tomsk; Alexander S. Yanyushkin, D.Sc. (Engineering), Professor, I.N. Ulianov Chuvash State University, Cheboksary
Vol. 24 No. 4 2022 5 CONTENTS OBRABOTKAMETALLOV TECHNOLOGY Dyuryagin A.A., Ardashev D.V. A study of the relationship between cutting force and machined surface roughness with the feed per tooth when milling EuTroLoy 16604 material produced by the DMD method...................... 6 Ulakhanov N.S., Tikhonov A.G., Mishigdorzhiyn U.L., Ivancivsky V.V., Vakhrushev N.V. The features of residual stresses investigation in the hardened surface layer of die steels after diffusion boroaluminizing............... 18 Rubtsov V.E., Panfi lov A.O., Knyazhev E.O., Nikolaeva A.V., Cheremnov A.M., Gusarova A.V., Beloborodov V.A., Chumaevskii A.V., Ivanov A.N. Development of plasma cutting technique for C1220 copper, AA2024 aluminum alloy, and Ti-1,5Al-1,0Mn titanium alloy using a plasma torch with reverse polarity................ 33 Amirov A.I., Moskvichev E.N., Ivanov A.N., Chumaevskii A.V, Beloborodov V.A. Formation features of a welding joint of alloy Ti-5Al-3Mo-1V by the friction stir welding using heat-resistant tool from ZhS6 alloy....... 53 EQUIPMENT. INSTRUMENTS Ardashev D.V., Zhukov A.S. Investigation of the relationship between the cutting ability of the tool and the acoustic signal parameters during profi le grinding..................................................................................................... 64 Bataev D. K-S., Goitemirov R. U., Bataeva P. D. Studies of wear resistance and antifriction properties of metalpolymer pairs operating in a sea water simulator........................................................................................................ 84 Zakovorotny V.L., Gvindjiliya V.E., Fesenko E.O. Application of the synergistic concept in determining the CNC program for turning............................................................................................................................................ 98 MATERIAL SCIENCE Sokolov R.A., Novikov V.F., Kovenskij I.M., Muratov K.R., Venediktov A.N., Chaugarova L.Z. The effect of heat treatment on the formation of MnS compound in low-carbon structural steel 09Mn2Si................................ 113 Burkov А.А., Krutikova V.O. Deposition of titanium silicide on stainless steel AISI 304 surface...................... 127 Pugacheva N.B., NikolinYu.V., BykovaT.M., Goruleva L.S. Chemical composition, structure and microhardness of multilayer high-temperature coatings..................................................................................................................... 138 Saprykina N.А., Chebodaeva V.V., Saprykin A.А., Sharkeev Y.P., Ibragimov E.А., Guseva T.S. Synthesis of a three-component aluminum-based alloy by selective laser melting............................................................... 151 Gabets D.A., MarkovA.M., Guryev M.A., Pismenny E.A., NasyrovaA.K. The effect of complex modifi cation on the structure and properties of gray cast iron for tribotechnical application..................................................... 165 Ivanov I.V., Yurgin A.B., Nasennik I.E. Kuper K.E. Residual stress estimation in crystalline phases of highentropy alloys of the AlxCoCrFeNi system........................................................................................................... 181 Korosteleva E.N., Nikolaev I.O., Korzhova V.V. Features of the structure formation of sintered powder materials using waste metal processing of steel workpieces................................................................................. 192 EroshenkoA.Yu., Legostaeva E.V., Glukhov I.A., Uvarkin P.V., TolmachevA.I., Luginin N.A., Bataev V.A., Ivanov I.V., Sharkeev Yu.P. Effect of deformation processing on microstructure and mechanical properties of Ti-42Nb-7Zr alloy............................................................................................................................................. 206 Kutkin O.M., Bataev I.A., Dovzhenko G.D., Bataeva Z.B. The study of characteristics of the structure of metallic alloys using synchrotron radiation computed laminography (Research Review)................................ 219 EDITORIALMATERIALS 243 FOUNDERS MATERIALS 255 CONTENTS
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 Investigation of the relationship between the cutting ability of the tool and the acoustic signal parameters during profile grinding Dmitrii Ardashev a, Alexander Zhukov b, * South Ural State University, 76 Prospekt Lenina, Chelyabinsk, 454080, Russian Federation a https://orcid.org/0000-0002-8134-2525, ardashevdv@susu.ru, b https://orcid.org/0000-0002-9328-7148, zhukovas@susu.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. 2022 vol. 24 no. 4 pp. 64–83 ISSN: 1994-6309 (print) / 2541-819X (online) DOI: 10.17212/1994-6309-2022-24.4-64-83 ART I CLE I NFO Article history: Received: 30 August 2022 Revised: 06 September 2022 Accepted: 21 September 2022 Available online: 15 December 2022 Keywords: Profile grinding, Profiled grinding wheel Actual cutting ability Acoustic signal analysis Spectral composition Natural frequency Informative frequency Sound index Funding The research was financially supported by the Ministry of Science and Higher Education of the Russian Federation (grant No. FENU-2020-0020). ABSTRACT Introduction. Modern mechanical engineering is closely connected with digital production management technologies, for which an important aspect is the collection of reliable information about the current state of the systems. Acoustic methods of current control of the tool cutting ability possess significant potential due to the possibility of continuously obtaining up-to-date data on the parameters of machining process. Profile grinding is one of the widespread methods of machining surfaces of complex configuration. The high importance of this method lies in the high degree of responsibility of shaped parts obtained with it. The wear parameter of profiled grinding wheels needs current control to the same extent as other types of cutting tools. At the same time, acoustic methods of research have not found wide application in relation to profile grinding. In view of this, the present work is aimed at studying the influence of the tool wear rate on the acoustic characteristics of grinding when using grinding wheels of different profiles. Purpose of work is to determine the acoustic parameters of profile grinding with application of planar grinding scheme as it wears out in comparison with analogical process with application of straight profile grinding wheel. As the basic methods of research an experiment is used to study the acoustic phenomena accompanying grinding with application of wheels of different profile. An analysis of the acoustic signal of grinding is carried out, as well as an analysis of the spectrum of its frequency composition. The frequencies of natural vibrations of grinding wheels of different profiles are investigated, its sound index is determined as a criterion for evaluating its characteristics. Acoustic characteristics of the grinding process with the use of grinding wheels of different profiles are compared. Regression analysis of acoustic data obtained as a result of the experiment is also used. Results and discussion. Spectrograms of frequencies of natural vibrations of the wheels under research, as well as a number of spectrograms of the acoustic signal accompanying the processing process for various technological conditions are received. As a result of comparing the obtained spectrograms, the informative frequencies of the grinding processes are determined. Mathematical models of sound level dependence on the value of periodic vertical feed St at depth t and processing time T are developed. It is established that the value of periodic vertical feed St at depth t has a greater influence on the acoustic index in comparison with the machining duration T. Practical significance and prospects of the results of the work lies in the possibility of increasing the efficiency of profile grinding processes due to the rational use of the tool availability. For citation: Ardashev D.V., Zhukov A.S. Investigation of the relationship between the cutting ability of the tool and the acoustic signal parameters during profile grinding. Obrabotka metallov (tekhnologiya, oborudovanie, instrumenty) = Metal Working and Material Science, 2022, vol. 24, no. 4, pp. 64–83. DOI: 10.17212/1994-6309-2022-24.4-64-83. (In Russian). ______ * Corresponding author Zhukov Alexander S., Post-graduate student South Ural State University, 76 Prospekt Lenina, 454080, Chelyabinsk, Russian Federation Tel.: 8 (351) 272-32-94, e-mail: zhukovas@susu.ru Introduction Tool condition monitoring (TCM) is one of the most important elements in intelligent machining automation systems [1]. Inevitable tool wear accompanying such machining depends on process conditions and directly influences the properties of the final product. Therefore, wear parameter monitoring and precise determination of current tool performance are key to product quality assurance.
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 As a widely used shaping method, grinding requires machining with a tool, the condition of which will ensure proper product quality. Dressing is used to return the original properties to the grinding wheel (GW). This also needs to be well timed for technological and economic reasons. TCM is the most effective tool to determine this moment. It is also performed at the end of the process chain, followed by finishing. Methods which do not require suspension of the production process, in order to determine wear parameters, i.e. indirect methods, are of interest among many approaches to determine GW condition. Acoustic methods (acoustic emission and noise diagnostics as per GOST 23829–85) are both indirect and passive methods, meaning that there is no external source of energy affecting the object of study. Many studies have focused on determining and predicting GW condition during processing through the use of acoustic emission signals [2]. It is shown that this method has a sufficiently high level of accuracy, information content [3], and sensitivity [4, 5] aimed at establishing current tool performance. However, this method is not common due to the high cost of equipment, and the need for specific signal transformations to filter it [6], etc. Furthermore, the method directly involving the acoustic wave generated by GW vibrations during processing (noise diagnostic) has been studied much less, despite its comparable practical potential [7]. Most of the main types of machining operations have been studied using acoustic methods (both acoustic emission and noise diagnostics): turning [8, 9]; milling [10]; micromilling [11]; drilling [12]; and grinding [13, 14]. All kinds of machined materials – brittle [15], ductile, composites [16], wood [17], have been considered. The studies have shown the applicability of the method for a wide range of process conditions of various machining operations aimed at determining the various parameters of the object to be studied. According to the majority of the authors of the works herein presented, the main aim of this method is to monitor cutting tool wear parameters. Researchers agree that acoustic monitoring methods are essential for practical application, in order to increase the process efficiency. Despite all the advantages of acoustic monitoring methods and its wide use in various types of processing, determining GW condition by this method in profile grinding has not yet found extensive application. Profile grinding is used for finishing complex shape surfaces and involves the processing of a workpiece with a grinding wheel with a pre-shaped profile. The aim is to ensure the required dimensions, shape, and surface quality (Fig. 1). The significance of the method lies in the high degree of responsibility connected with the production of the profiled parts. Surveys show that despite the high demand for profile grinding in mechanical engineering, the acoustic phenomena of this process have been poorly studied. Nevertheless, there is a demand for determination of the current cutting capacity of the profiled GW and predicting its durability period [18, 19, 20]. A deeper insight into this issue will allow rationalizing the consumption of cutting tools and increasing the efficiency of profile grinding in digital production. An acoustic method for TCM in profile grinding needs to be developed. This is also connected with the need for expedient profile tool dressing in this type of processing, as well as in other types of grinding. The purpose of this research is to establish the acoustic parameters of flat grinding with a profile wheel as it wears out, as opposed to a similar process using a straight profile wheel. The tasks to be solved to achieve this purpose are listed below. Since the sound pressure generated by grinding results from the natural vibrations of the wheel [21], it is necessary to study the natural vibration frequencies (NVF) of grinding wheels of various profiles. Fig. 1. Profile grinding of bearing rings: a – external; b – internal
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 Task 1 – to determine experimentally the NVF of the grinding wheels studied here, in order to perform an analytical comparison of the NVFs of grinding wheels of various profiles. Task 2 – to assess the contribution of the idle operation of the main systems in the experimental setup (in idle mode) to the overall spectrum of acoustic vibrations. Task 3 – to establish experimentally the acoustic parameters of flat grinding with wheels of various profiles (spectral composition, sound level amplitudes). Task 4 – to perform a qualitative comparison of the data acquired, in order to identify the distinctive features of the acoustic signal during profile grinding. Research methodology The experimental study consists of two stages. The first stage studies the natural vibration frequencies of grinding wheels. The second stage is focused on acoustic signal during processing. Each stage uses a GW of a straight profile and a profiled wheel. GW 1 is a standard straight profile grinding wheel, GW 2 is a grinding wheel profiled for grooving (Fig. 2). Stage 1.Aprerequisite for studying the natural vibrations of the GIWs is the existing relationship between the parameters of natural vibrations: physical and mechanical properties; and the geometric characteristics of a solid body [22]. ( , ) , L f F a C = µ (1) where F (a, μ) is the shape factor dependent on the geometric dimensions of the body, its shape, and Poisson’s ratio; L E C = ρ is the parameter which represents the propagation speed of elastic vibrations in an infinitely long rod, the material of which is similar to the material of the body under consideration; E is the elastic modulus; ρ is the material density. The shape factor F∙(a, μ) in this study is based on recommendations from the reference documentation (GOST R 52710–2007 Abrasive tool. Acoustic method for determining the hardness and sound indices by the acoustic wave propagation speed). The use of the method for determining the natural vibration frequency of the wheels and the sound indices as proposed in this standard is consistent with the aim of the study. The purpose of this stage is to determine the spectral composition of the acoustic signal excited by the impact force in the grinding wheels of various profiles. The variable factor of the experiment is the GW profile. The study parameter is the spectral composition of the natural vibrations of the GW. Stage 2. The indirect (acoustic) characteristic of surface pendulum grinding depends on the tool profile during wear in different modes. The characteristics of the sound generated by similar processes using GW 1 and GW 2 are compared. In addition to geometric parameters, the tools used have no differences the wheel characteristics are identical. Experimental study of the natural vibration frequencies of grinding wheels Yuganov V.S. [23], in his study of low-frequency acoustic vibrations (LAV) during flat grinding, concludes that there is an almost complete coincidence of the informative frequencies characteristic of the grinding process and the natural frequencies of the wheel (Fig. 3). This conclusion was later confirmed by Agafonov V.V. [24]. As a result, the authors affirm that the direct source of vibrations at the informative frequency is the grinding wheel. Based on this assumption, the object of the study is the 2,700 rpm 1 250×32×76 25A Fig. 2. Profile of the tool used: а – GW 1; b – GW 2
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 F46 K 6 V 35 grinding wheel, pursuant to GOST R 52781–2007. The subject is the spectral composition of the natural vibration frequencies of GW 1 and GW 2. An ICHSK-2 natural vibration frequency meter was used to register and process the acoustic signal, and determine the spectral composition of the natural vibration frequencies of the grinding wheels. This device is designed for acoustic monitoring of the physical and mechanical properties of objects and detecting product defects using the spectral analysis of the acoustic signal of the object’s response. In particular, the ICHSK-2 has a mode to study grinding wheels. This enables the sound index (SI) of the wheel to be established, and, based on this, to determine the hardness degree of the object pursuant to GOST R 52710 – 2007. The device determines the SI based on the physical and mechanical properties of the material of the grinding wheels, as well as its geometric parameters (Table 1). Four experiments were carried out on each test object (GW 1 and GW 2). According to the data summarized in Table 1, the SIs of the grinding wheels were determined according to its physical, mechanical, and geometric parameters. Experimental study of acoustic signals during flat grinding The section describes a comparative experimental study of acoustic signals during flat grinding using wheels of varying profiles. The object of the study is flat pendulum grinding; the subject is an acoustic signal, accompanying this process. Fig. 3. Grinding wheels straight profile bending vibrations 250×H×76: Informative frequencies and Natural frequencies obtained experimentally [23] Ta b l e 1 Parameters of the grinding wheels required to determine the sound index Parameter GW 1 GW 2 GW designation 1 250×32×76 25А F46 K 6 V 35 2700 rpm GOST R 52781-2007 Abrasive material type white electrocorundum 25 A GW dimensions (D×H×d), mm 250×32×76 250×32×76 GW shape factor (F), m-1 0.001175 0.001182 GW mass (m), kg 3.14 2.72 GW density (ρ), g/cm3 2.02
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 b c Fig. 4. Experimental setup: a – general view; b – using GW 1; c – using GW 2; 1 – tool; 2 – magnetic table; 3 – workpiece (sample); 4 – microphone; 5 – personal computer а Ta b l e 2 Processing modes Mode Value Rotational speed of the GW Vk, rpm 2,700 Intermittent vertical feed St to a depth of t, mm/double stroke 0.01 / 0.015 / 0.02 Longitudinal feed of the table (workpiece) Vs, m/min 5 Grinding width lg, mm 25 / 34 Processing time T, min 15
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 The experimental setup (Fig. 4) was mounted on a universal high-precision 3G71M flat surface grinding machine with a horizontal spindle and a rectangular table. 140×25×30 mm samples of carbon structural Steel 30 (30 % C) with a hardness of 37–41 HRC in the form of rectangular parallelepipeds were subjected to grinding. A 140×25 mm plane was processed with GW 1. A triangular groove with an angle of 90º and a length of 140 mm was processed with GW 2. The grinding modes are presented in Table 2. Before processing, the grinding wheels are affixed in a statically balanced faceplate, mounted on the machine spindle, and dressed. The aim of each individual experiment is to establish (record) acoustic signals for the established technological conditions. The acoustic signal was recorded using a non-contact sensor. This was a compact directional microphone fixed on a tripod at a distance of 50 – 100 mm from the end surface of the tool. The analog acoustic signal received by the microphone was digitized by a PC sound card. A WDM sound card was used. SOUNDFORGEPro 13.0 was used as the software to work with the acoustic data acquired. The arithmetic mean deviation of the sample profile (Ra, μm) was measured, in order to assess the quality of the ground surface using a contact profilometer with accuracy degree 1, pursuant to GOST 19300–86 (model 130). The processed surfaces were conditionally divided into five equal sections followed by five measurements of roughness inside each section in the direction of the longitudinal feed of the table VS and perpendicular to VS. The length of the baseline that was used to determine the microprofile of the sample surface was 4 mm. The described methodology is a set of elements of the methodologies used in previous studies with a similar focus [23, 24]. The methodology was finalized and adapted taking into account the purpose of the study. The applied equipment, hardware, and software correspond to the purpose and objectives of this work and allow the required parameters to be established with sufficient accuracy. Study of the acoustic signal of idle operation of the experimental setup In the framework of this work, it is necessary to reflect separately the influence degree of “noise” that accompanies the operation of machine units and “noise” that does not carry information useful for research. Even in laboratory conditions, it is impossible to separate the acoustic signal of one particular source. Many elements of the machine system make its own contribution to the overall acoustic picture during processing. A preliminary study of the acoustic signals accompanying the idle operation of the machine is required, in order to achieve an insight into this contribution. When implementing this method in real production, the contribution of other sources of noise signals should be studies. In this study, the various acoustic signals which do not carry information on the properties and condition of the tool will be called noise interference or noise. The signal, generated by the elastic vibrations of the GW during processing and changes depending on the degree of its wear, will be called an informative (useful) acoustic signal [23]. We analyzed the spectrum of acoustic vibrations of the basic elements in the process system, the operation of which is accompanied by noise background. We also considered the spectral composition during the series connection of the systems of (1) power supply, (2) hydraulic power plant, (3) spindle rotation, and (4) longitudinal feed of the table Vs. Results and discussion The section describes the results obtained during the experiment and its interpretation. Natural vibration frequencies and the sound index of the grinding wheels of various profiles Natural vibration frequencies. Figures 5 and 6 show the spectrograms of natural vibration frequencies for GW 1 and GW 2, respectively. Although the material of the grinding wheels and its physical and mechanical properties are identical, the NVF distribution spectra are different. This allows us to assert that the shape of the wheel strongly influences the nature of elastic vibrations.
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 A grinding wheel is considered to be a solid elastic isotropic body in the form of a disk with a central hole (sometimes as an annular plate) [22, 23, 24]. The proposed disk is a round plate, the thickness of which (wheel height H, mm) is small in relation to the diameter (wheel diameter D, mm), which has a central axial hole (bore diameter d, mm). Each excess kurtosis on the spectrograms (Fig. 5, 6) indicates the physical frequency, at which vibrations appear with a certain mode: the spatial configuration of the vibrations of the grinding wheel points under the impact force (GOST R ISO 2041–2012). The graphs show that each wheel is characterized by the simultaneous appearance of several vibration modes. Each of the modes has its own shape – i.e. spatial configuration. This is when the points on its surfaces are at the maximum distance from the equilibrium (resting) position. Dominant modes are manifested at high sound levels. Due to significant deviations of body microvolumes from the equilibrium state, dominant modes are characterized by a more powerful acoustic signal recorded by the device at a certain frequency. Modes with the lowest natural vibration frequency are called fundamental natural modes. With regard to GW 1, the fundamental natural vibration mode ffun1 = 2.062 Hz; for GW 2, ffun2 = 2.337 Hz. Sound index. An elastic acoustic wave propagating in the material of the grinding wheel and excited by the impact force has several specific characteristics. In our study, the illustrative characteristics are the normalized speed of its propagation CL and the sound index. The sound index is a normalized integrated index, i.e. the value of CL averaged in a certain range, provided for by GOST R 52710–2007 and used in acoustic monitoring [25, 26]. The connection of the SI with the shape factor of the object, Young’s modulus (E-modulus), and the material density makes it a highly informative parameter enabling certain physical and mechanical properties of abrasive materials to be established, in particular the hardness degree. The tests results enabled us to establish SI for each of the objects under study according to its parameters (Table 1). The sound indices for GW 1 and GW 2 took identical values and amounted to 47 units. This corresponds to the hardness degree K, pursuant to GOST R 52587–2006 (or CM1 as per GOST 2424–83). The values of the degree of hardness coincide with the marking as set by the manufacturer. The normalized acoustic wave propagation speed CL recorded by the ICHSK-2 device falls within the range of 4,600–4,800 m/s. Based on the measurement results, the properties of the materials of GW 1 and GW 2 do not differ, which is factually correct. In this case, the change in the shape of the tested GW did not affect the SI value, i.e. the acoustic wave propagation speed CL did not change, since this indicator depends on the physical Fig. 5. Spectral composition of GW 1 natural vibration frequencies
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 Fig. 6. Spectral composition of GW 2 natural vibration frequencies and mechanical properties of the material, which remained unchanged. At the same time, we recorded significant changes in the spectral pattern of the NVF distribution, indicating the independence of the SI and NVF parameters. We thus established that wheels of various geometric shapes studied herein are characterized by the different spectral composition of natural frequencies. At this stage of study, these differences do not show any regularity. Acoustic signals accompanying the idle operation of the 3G71M flat surface grinding machine We studied the acoustic signal accompanying the operation of the 3G71M machine systems. Using a microphone, we recorded acoustic signals accompanying the series connection of the systems: (1) power supply; (2) hydraulic power plant; (3) spindle rotation; and (4) longitudinal pendulum feed of the table (Vs). Table 3 shows spectrograms which reflect the acoustic vibration frequency distribution for the recorded signals. At the first stage, we recorded a signal from the operation of the power supply system only, while at the last stage, – from all the above systems. Since dry grinding is used during the experiment, we did not need to take into account the operation of the coolant supply system. Analysis of the spectrum of acoustic vibrations of the process system (PS) elements showed that the grinding wheel spindle rotation made the maximum contribution to the acoustic picture of the idle machine operation (Table 3, (3)). A significant increase in the sound level in a wide frequency range (from 2 to 7.5 kHz) reached about 26% (Fig. 7) relative to the stage involving the power supply and hydraulic systems. This is caused by the combined action of the individual units of the grinding head: M3 electric motor of the grinding wheel (2.2 kW, 2,860 rpm, 50 Hz, version M101 with KZ MRTU16 – 510.002–65 AOL2 – 22 – 2 – CI terminal box); flat belt pulleys; three-point bearings; spindle; grinding wheel. The acoustic signal corresponding to the operation of the hydraulic power plant was reflected in the frequency range of 250 – 650Hz as a stable excess kurtosis recorded on each of the presented spectrograms (except the first one). The sound level is pulsating in time, corresponding to the operating features of the oil pump. The sound level is from –17 dB to –50 dB. The systems of power supply and longitudinal feed of the table (Table 3 (1), (4)) do not generate significant acoustic disturbances of the process system elements, do not introduce significant changes in the overall acoustic picture of the idle operation of the experimental setup.
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 Ta b l e 3 Acoustic signal spectrograms of 3G71M machine systems Active system Spectrogram (1) power supply + (2) hydraulic power plant + (3) spindle rotation + (4) longitudinal feed An important fact to be considered in the further research is the stable “dip” in the idle operation spectrograms in the range of 1,900–2,100 Hz. When new overtones appear in the indicated range, we can affirm that it was caused by something not related to the sound of the idle machine operation. Thus, the spectral composition presented in Table 3 (4) is the relatively constant background “noise” accompanying the processes under study. This acoustic component should not be taken into account when
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 Fig. 7. Idle operation acoustic signal spectrogram of the experimental setup main systems considering the change in the tool condition during grinding. In particular, the constant excess kurtoses present in the spectrograms (Fig. 7–11) in the ranges of 550–650 and 2,650–2,700 Hz are definitely related to the operation of the hydraulic system pumps. At the same time, it should be understood that the sound level cannot increase significantly within the indicated frequency limits during the normal operation of the hydraulic system. Acoustic signals accompanying processing with the grinding wheels of various profiles The test samples were ground for 15 minutes (900 seconds). The influence of the shape of the GW profile, the value of the periodic vertical feed St to the depth t, and the duration of grinding T on the acoustic phenomena accompanying the machining process were studied. The main results of studying the acoustic Fig. 8. Spectrograms of initial processing stage with use GW 1 and St1 = 0.01; St2 = 0.015; St3 = 0.02 mm/double stroke feeds Fig. 9. Spectrograms of final processing stage with use GW 1 and St1 = 0.01; St2 = 0.015; St3 = 0.02 mm/double stroke
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 Fig. 10. Spectrograms of initial processing stage with use GW 2 and St1 = 0.01; St2 = 0.015; St3 = 0.02 mm/double stroke Fig. 11. Spectrograms of final processing stage with use GW 2 and St1 = 0.01; St2 = 0.015; St3 = 0.02 mm/double stroke signals are presented in the form of spectrograms of acoustic vibration frequency distribution for various process conditions and subject to comparison. No significant and stable acoustic excess kurtoses are observed in the high-frequency range (>8 kHz). Furthermore, analysis of the spectrograms of the idle operation of the setup showed that significant excess kurtoses appear in the low-frequency region of the spectrum (˂1,000 Hz). To this end, we considered the spectrograms in the range of 1–8 kHz. The spectrograms of the initial processing stage (Fig. 8, 10) differ from the idle operation spectrogram in terms of new excess kurtoses. An additional source of acoustic vibrations here is only grinding (removal of surplus) with a dressed wheel. This process can be observed in the spectrograms in the form of increases in the amplitude of the sound level in the range of 1,400–2,000 Hz for processing with GW 1, and in the range of 1,400–2,400Hz for processing with GW 2. It can be concluded that the applied acoustic method is sensitive to the process under study. The initial stage is also characterized by weak differences in the spectral compositions for different values of the periodic vertical feed. This applies in particular to the process using GW 1. Wheel surface diamond dressing involves a running-in stage. This stage can vary in duration depending on the periodic vertical feed, but the same mechanism for transforming the tool surface due to the removal of unfavorably oriented abrasive grains. At the final stage, processing is performed with a tool, which has lost its original characteristics and has reduced cutting capacity. While the normal operation stage [27] corresponds mainly to the wearing of the peaks of abrasive grains and surface chipping, in the moment under consideration (emergency stage) it is already characterized by bulk failure of the grains and shearing from the bond. Intensively increasing tool wear and a decrease in its cutting capacity have the following manifestations in the spectrograms of the final processing stage (Fig. 9, 11). We can see a significant increase in the amplitude of the sound level in a wide
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 frequency range. This is strongly manifested during grinding in harder modes (St2, St3). The amplitude of the sound level also increases for small values of St (St1), albeit to a lesser extent. For the final processing stage with GW 1, the most characteristic frequency ranges containing significant increases in the amplitude of the sound level are: 2,150 ± 150 Hz; 3,500 ± 300 Hz; 4,900–5500 Hz; and 6,750 ± 200 Hz. We can similarly list the frequency ranges inherent in the final processing stage with GW 2: 2,070 ± 200 Hz; 2,750 ± 250 Hz; and 5,500–6,150 Hz. Thus, due to the differences in the spectral composition of acoustic vibrations and the absence of other factors able to change it significantly, we can affirm that the shape of the grinding wheel significantly affects the spectral composition of acoustic vibrations during processing. Moreover, changes in the cutting capacity during grinding are also reflected in the spectrograms of the process acoustics. We then compare the frequency distributions of acoustic signals obtained when studying the NVF of wheels and the grinding process. To this end, we place the graphs of the NVF (Fig. 5, 6) and the spectrograms of the grinding process at the final processing stage (Fig. 9, 11) in a single coordinate system in a simplified form and make a visual comparison (Fig. 12). Let us single out the main frequency intervals containing significant excess kurtoses which develop in the course of processing. In order to do this, we need to take into account the noise accompanying the operation of the experimental setup units. Figure 12 schematically shows a comparison of the NVF of the grinding wheels and the acoustic signal frequencies recorded during grinding. The dominant natural vibration frequencies of the grinding wheels are 2,062 Hz and 2,337 Hz for GW 1 and GW 2, respectively. These vibration frequencies were used to calculate the propagation speed of the sound wave CL, and to determine the sound index. The graph in Figure 12 shows that there is no complete coincidence of the natural vibration frequencies of the grinding wheel with the frequencies of acoustic signals during grinding, as stated by V.S. Yuganov [23]. However, there are fairly close values of Fig. 12. Comparison scheme of grinding wheels natural vibrations frequencies and frequencies of acoustic grinding signal
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 these frequencies. The closest values are observed when considering the NVF of GW 1 and the frequencies during grinding with a straight profile wheel: 2,062 Hz and 2,150 Hz, respectively. In the event of a similar comparison of GW 2, the frequency difference is more significant: natural vibrations – 2,337 Hz: and grinding – 2,070 Hz. It can thus be confirmed that the source of the acoustic signal during grinding is the grinding wheel. Informative frequencies for the processes using GW 1 and GW 2 are, respectively: fGW1 = 2,050 – 2,250 Hz; (2,150 ± 100 Hz); and fGW2 = 1,970–2,170 Hz (2,070 ± 100 Hz). As a result, we found that when studying the relationship between the acoustic characteristics of the grinding process and the tool cutting capacity for various process conditions (tool profile, the periodic vertical feed to the depth t, and the duration of processing), the dominant natural vibration frequencies of the grinding wheels need to be taken into account, since it can be used to determine the informative frequencies. Mathematical modeling of the sound level parameter during grinding with the tools of various profiles If we have data available on the dynamics of the acoustic signal during grinding, we can develop regression models (2, 3) which describe the dependence of the sound level (β, dB) on the processing time (T, min) and the periodic vertical feed to the depth t (St, mm/double stroke) for each of the wheels. 1 38.6 128.7 0.096 ; GW t S T β = − + + (2) 2 36.05 75.9 0.29 . GW t S T β = − + + (3) The statistical significance of the equations was verified using the determination coefficient and Fisher’s criterion. With regard to equation (2), the determination coefficient is R2 = 0.46, and for equation (3) R2 = 0.63. The calculated value of Fisher’s criterion for equation (2) F GW1 = 36.5, and for equation (3) FGW2 = 73.4. The table values of the criterion for the equations coincide, since during statistical processing it has an equal number of the degrees of freedom: Ftabl = 3.07. Since in both cases, the actual value of Fisher’s criterion significantly exceeds the critical (tabulated) value, we can conclude that the determination coefficients are statistically significant and the regression equations are statistically reliable. In addition the coefficients at St and t are jointly significant. Mathematical models (2) and (3) describe the dependence of the acoustic parameter – the sound level of a certain frequency on the periodic vertical feed to the depth t and the processing time. The models have both similarities and considerable differences. Analysis showed that the periodic vertical feed to the depth t (St, mm/double stroke) has a greater influence on the sound level (similar to [28]) as compared to the processing time (T, min). At the same time, the processing time factor is more important for equation (3) than for equation (2). Thus, GW 2 processing time has a greater influence on the sound level than GW 1 processing time. The applied significance of these models lies in the possible prediction of the sound level, in the aims of monitoring current cutting capacity in the ranges of St from 0.01 to 0.02 mm/double stroke, and the processing time from 0 to 15 minutes. The mathematical models thus obtained for determining the acoustic parameters (amplitude of the sound level) can be used correctly, only if the informative frequencies, for which these models were developed, match. Roughness study. The roughness of the workpieces was studied at the end of the processing cycle which lasted for 15 minutes. The results of the measurements are presented in the graphs of Figure 13. We established the dependence of the arithmetic mean deviation of the sample profile (Ra, µm) on the periodic vertical feed to the depth t (St, mm/double stroke). The graphs show that the surface roughness formed by profile wheel GW 2 is always much higher than when compared to the processing using GW 1. Thus, measurements in the direction of the longitudinal feed VS differ by 20 %, and measurements taken perpendicular to the VS direction – by 70 %. The roughness also increases with an increase in the periodic vertical feed to the depth t. Although the values for GW 2 exceed those for GW 1 for the measurements taken along the VS direction, it increases more slowly (depend
OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 4 No. 4 2022 b Fig. 13. Dependence of roughness on the value of periodic vertical feed St at depth t: a – for GW 1; b – for GW 2 а less on St). The roughness obtained for St1 = 0.01 mm/double stroke differs from the roughness obtained for St3 = 0.02 mm/double stroke by 2.3 times for GW 1, and 1.6 times for GW 2. Since the use of GW 2 increases the area of the contact spot of the tool with the workpiece (by 35 %), the processing requires more power consumption. This is consistent with the conclusions of Ermolaev V.K. [29]. Tougher processing conditions implemented on the same equipment worsened the quality of the processed surface. Line of further research. The acoustic method, which has gained reputation in many types of processing, can provide high-quality information support, if sufficiently studied. Therefore, identifying the features of the acoustic characteristics inherent in profile grinding and establishing the relationship between it and the wear rate of the grinding wheel, allow the current condition of the tool to be established. It also opens the way for adjusting the grinding modes according to the product quality requirements. The main line of further research in this area is the upgrading of the mathematical models and expanding the area of its practical applicability. In order to establish a reliable relationship between the indirect acoustic parameters of profile grinding and the quality characteristics of the processed surface, the dynamics of changes in the micro- and macrotopography of the surface of the grinded workpieces over time need to be studied. The significance degree depends on the variety of experimental factors and, accordingly, the applicability of models in a
OBRABOTKAMETALLOV Vol. 23 No. 3 2021 MATERIAL SCIENCE EQUIPMENT. INSTRUMENTS 4 4 2 wider range of process conditions. Such conditions, first of all, include: process flow diagrams and grinding modes; geometrical parameters of GW profiles and characteristics; and work piece material. When choosing factors, which influence the studied acoustic parameters and quality characteristics, we need to proceed from the current production needs. An important stage in this work is to determine the informative frequencies using the analysis of the natural vibration frequencies of grinding wheels. Since the applied method showed close values of NVF, and informative frequencies of the acoustic signal during grinding, it would be expedient to continue research in this area and focus on grinding wheels of other geometry. The outcome of the planned study will consist in the development of guidelines to choose efficient technology for the processing of a batch of workpieces. This will in turn depend on volume and quality requirements based on the characteristics of the acoustic signal. Conclusions Within the framework of this work, a study of profile grinding by the acoustic method was carried out. The informative acoustic range associated with the change in the state of the grinding wheel as the processing progresses is determined. From which it follows that the goal of the work has been achieved. The main conclusions of the study can be listed as follows: 1. The nature of the spectral composition of the natural vibration frequencies of the grinding wheel depends on its shape. There are significant differences in the NVF spectrograms for objects of different shapes. The empirically determined sound index showed no dependence on the shape of objects, since it is an indicator of physical and mechanical properties. 2. The study of the acoustic signal accompanying idle operation of the experimental setup showed that the spindle rotation with the grinding wheel made the most significant contribution to the acoustic picture. Furthermore, we established the influence of the hydraulic system on the acoustic signal in the lowfrequency acoustic range (˂ 1,000 Hz). As a result, it will be further expedient to carry out a study of the spectrograms of the acoustic signal of grinding in the range from 1 to 8 kHz. 3. We identified the frequency ranges when the amplitude of the sound level increases during grinding with GW 1 and GW 2. These ranges are: – for GW 1: 2,000 – 2,300 Hz, 3,200 – 3,800 Hz, 4,900 – 5,500 Hz, 6,550 – 6,950 Hz; – for GW 2: 1,870 – 2,270 Hz; 2,500 – 3,000 Hz; 5,500 – 6,150 Hz. We established informative frequency ranges: fGW1 = 2,050 – 2,250 Hz; (2,150 ± 100Hz); and fGW2 = 1,970 – 2,170 Hz (,2070 ± 100 Hz). We showed the dependence of NVF and acoustic signals during grinding. Preliminary assessment of NVF allows the informative frequencies of the acoustic signal of grinding to be determined when the wheels of various profiles are used. 4. Using the regression analysis of acoustic data, we developed mathematical models for the dependence of the sound level (β, dB) on the periodic vertical feed to the depth t (St, mm/double stroke), and the processing time (T, min) for the considered tools: 1 38.6 128.7 0.096 ; GW t S T β = − + + 2 36.05 75.9 0.29 . GW t S T β = − + + It has been established that the sound level can act as an indirect criterion for determining the current state of the grinding wheel during of processing, which makes it possible to maintain the specified quality requirements for the workpieces. References 1. Zhou C., Guo K., Sun J. Sound singularity analysis for milling tool condition monitoring towards sustainable manufacturing. Mechanical Systems and Signal Processing, 2021, vol. 157, pp. 1–17. DOI: 10.1016/j. ymssp.2021.107738.
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