Investigation of complex surfaces of propellers of vehicles by a mechatronic profilograph

OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. No. 4 2021 and geometric characteristics of the form surfaces of products right away even using computer-aided design system. At the same time, there is a problem of reliability and diagnostics of these parts and units during operation. For example, breakdowns and failures associated with a violation of the geometry of propellers when coming in contact with foreign objects in air and water are quite possible. To study complex propeller surfaces of vehicles, reverse engineering using a mechatronic pro fi lograph [1] is proposed. Reverse engineering allows representing a point cloud in the digital form of a physical part or a machine unit. As a rule, a point cloud is topological information about the geometry of a complex surface of a product, which can be used to create its digital model. This method is used quite often when copying machine parts in the absence of design documentation or 3D models, when improving the units with complex surfaces, as well as for creating digital models of products for virtual research in CAD liquid media. The application of reverse engineering methods is relevant in various branches of the national economy: mechanical engineering, agriculture, medicine and others. Therefore, the question of founding a Reverse Engineering Center at the Industrial Development Fund of the Russian Federation was raised by the Minister of Industry and Trade of the Russian Federation D. V. Manturov at a meeting of the Government Commission on Import Substitution. The surface of a complex part is not always perfect, smooth and geometrically correct. More over certain micro- and macro-geometric imperfections can be found on the surface. Waving and surface shape deviations are macro-geometric imperfections of a complex part. The ratio of the pitch deviation to the value of the deviation from the nominal contour is used in the current work to evaluate waving and surface shape deviations. For example, for shape deviation, the ratio of the pitch to the deviation value is more than 1,000. Pro fi lographs (from “ pro fi le ” and “ graphic ”) are used to specify these parameters in metalworking. They allow measuring surface imperfections and present the results in the form of a pro fi logram that characterizes the waving, roughness and shape of the surface. GOST R ISO 4287-2014 “Geometrical Product Speci fi cations ( GPS ). Surface texture. Pro fi le method. Terms, de fi nitions and surface texture parameters” standardizes not only roughness indicators, but also waving, as well as indicators of the primary pro fi le. Therefore, today the transition of machine-building enterprises to GOST R ISO 4287-2014 is accompanied with a number of dif fi culties, besides there is a need for new and modern measuring equipment that can generate pro fi lograms to implement the pro fi le method. Today there are various methods to obtain information on a physical object by means of different data collecting devices. For convenience they can be divided into two groups of methods: contact methods – atomic-force microscopy, stylus pro fi lometry, etc. [2, 3] and non-contact methods – methods that use laser devices, image processing, and others [4–8]. For example, the morphological parameters and the shape of complex surfaces were determined in works [9–11] on mechanical engineering, in works [12–15] for agri- culture. Amechatronic pro fi lograph that scans the surface by the cylindrical method has been developed by S. A. Vasilyev [16, 17]. The main advantages of this group of methods include the time of obtaining infor- mation, its accuracy, convenience and usability of devices. There are also disadvantages that appear in the study of surfaces associated with the phenomenon of diffraction of laser beams on smooth areas, but these errors can be eliminated by program while processing the information [18]. Taking into account the above, we formulate the purpose of the research – the development of a new technology for studying complex surfaces of propellers, which include marine and aircraft propellers of vehicles, mechatronic pro fi lograph for the implementation of reverse engineering. To achieve this goal, it is necessary to solve the following tasks: – to propose a technology for studying complex surfaces of propellers of vehicles and the design of a mechatronic pro fi lograph on the basis of the review of reverse engineering methods and measuring devices; – to develop a mechatronic pro fi lograph; with its application to conduct theoretical and experimental studies of complex surfaces of screw propellers of vehicles; to obtain and process information about their pro fi le;