Experimental study of the relationship between the vibro-acoustic parameters of the grinding process and the macro-roughness of the treated surface

OBRABOTKAMETALLOV Vol. 23 No. 3 2021 technology surface can be taken into account by the use of the amplitude-frequency characteristics of the technological system (TS). Many mathematical models, methods of diagnostics and forecasting of the states of various parameters of the technological system (TS) are based on taking into account the vibration characteristics of the grinding process today: the technical condition of the grinding equipment [2]; the current state of the grinding wheel (GW) [3-5]; the quality of the processed surface [6]; deviations from circularity taking into account the kinematics of the process during centerless grinding [7, 8], etc. The negative impact of high-amplitude vibrations on the TS in general (increased wear of machine components and the increased likelihood of its premature failure) and on the product quality in particular (reduced accuracy and roughness parameters and shape deviations) is beyond doubt and requires the development ofmethods and techniques for its early detection [9] and subsequent elimination orminimization [10–12]. We can see from the literature that the solutions to most problems related to production planning, predicting the state of TS, optimizing grinding modes, and leveling processing errors, etc. are based on the development of mathematical models. The advantage of using mathematical modeling to describe complex processes and production systems is that this method allows one to study a specific parameter irrespective of its insignificant characteristics and avoids the high costs of direct study. The construction of a model and establishing a connection between the factor(s) and the response allows one to identify the new qualitative characteristics of an object which are not obvious when other methods are used. In the light of this, the purpose of this work is to develop a mathematical model of the relationship between the vibro-acoustic parameters of ECPCG and the macro-roughness of the grounded sample. To achieve this purpose, the following tasks should to be solved: – setting up an experiment; – processing of experimental results; – development of a mathematical model of sound characteristics; – development of a mathematical model of deviations from the cylindricality; – development of a generalizing mathematical model of the relationship between (3) and (4). This study is carried out to develop a methodology for predicting the durability of the grinding wheel based on the sound level of the grinding process, which does not require significant resources for measurement and processing. Such a methodology increases the efficiency of grinding operations in high- variety production settings. Research methodology The object of the experimental research is ECPCG. The subject of research is the acoustic characteris- tics of this process. The experiment (Fig. 1) was carried out on the 3M151F2 circular grinding machine using a grinding wheel 1 600×50×305 25А F46 L 6 V 50 2cl GOST R 52781–2007. Processing modes: – wheel rotation speed V = 50 m/s; – radial feed rate of the wheel S R , depending on the experiment = 0.2; 0.3; 0.5; 0.8 mm/min; – rotation speed of the workpiece in the centers S C = 25 m/min; – grinding width l g = 10 mm; – duration of processing t 1 = 1 min, t 2 = 2 min, t 3 = 5 min. The samples used for the experiment are steel 45 disks with a diameter of 70 mm and a hardness of 50-55 HRC. When planning the experiment, we took into account existing studies of the wear of grinding wheels [13]. The process conditions are taken from the conditions often used in production and which have already been investigated.