OBRABOTKAMETALLOV technology Vol. 24 No. 4 2022 DMD increases material utilization because the final product is manufactured by adding the desired amount of material rather than removing it from a solid workpiece; local deposition of material is possible. This method is widely used for coating and the restoration of worn surfaces with powders [4–6]. However, DMD is associated with producing surfaces that do not fully meet the functional requirements [7–10]. Thus, subsequent machining is required. Since DMD is not used in mass production, there are no references for cutting modes for its processing. Most companies machine grown items, selecting suitable cutting modes and cutting tools by trial and error. However, such processing is not effective due to material consumption. Theoretical and experimental testing is required to establish the relationship between the operating parameters and output parameters of the cut. Research data enables the development of a base of recommendations for assigning rational modes of machining DMD-materials. A large number of studies report the characteristics of machining new materials [11-13] and show that the mechanical engineering industry is interested in these materials for the production of parts with the necessary properties. An experimental study of the machinability of Al/SiC-MMC was conducted in [14]. The influence of cutting depth, feed, and cutting speed on the roughness of the machined surface and the cutting force were analyzed. The data established the relationships between these factors, and showed its influence on cutting tool wear. The results enable the selection of suitable values for the feed, cutting speed, and the depth of cut to meet the functional requirements. Eun-Jung Kim et al. [10] conducted an experimental study on the machining of 304L stainless steel. Numerical values of the cutting force and surface roughness were determined to establish the machinability of the material. An experimental model of the relationship between machined surface roughness and cutting modes (spindle speed and feed rate) in turning DMD-produced VT6 titanium alloy was developed in [15]. The milling of IN718 material samples produced using additive technologies are presented in [16–18]. Thus, cutting force, cutting tool wear, surface roughness, and residual stresses under different technological conditions were analyzed. Machinability and the machining process of deposited materials were studied to form a regulatory base for cutting modes. Such data will improve the efficiency of machining operations, which is relevant to the mechanical engineering industry. The purpose of this study is to identify the functional relationship between the cutting force and machined-surface roughness and the feed per tooth during the end milling of DMD-produced EuTroLoy 16604 to improve the efficiency of machining operations. In the furtherance of this goal two steps were taken. - an experimental study of the machinability of milling EuTroLoy 16604 by end mills at different cutting angles, measuring the cutting force and the roughness of the machined surface, was conducted. - mathematical models of the relationship between cutting force and machined surface roughness and feed per tooth were constructed. Research Methodology The sample for the study is a layer of EuTroLoy 16604 powder deposited on a steel plate using DMD (Fig. 1). The layer was deposited in the research laboratory of mechanics, laser processes, and digital production technologies at the South Ural State University using the FL-Clad-R-4 laser cladding complex [19]. The substrate is a plate of structural fine carbon Steel 45 (0.45% C). Deposition modes: laser power – 1,600 W; laser scanning speed – 10 mm/s; powder flow rate – 10.5 g/min; scan step – 1.4 mm. The chemical composition and the size of the powder main fraction are given in Table 1. Amicrostructural examination of the deposited layer was performed using a JEOL JSM 7001-F scanning electron microscope with an X-Max-80 Oxford Instruments X-ray fluorescence energy dispersive analyzer. Thee indentations of the sample were made to measure the microhardness in the depth of the deposited layer using a HV-1000 microhardness tester.
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