OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 6 No. 4 2024 Introduction Machining is used to produce complex profi le surfaces. This method has a number of technological and economic disadvantages. To obtain diff erent profi les, it is necessary to manufacture diff erent profi le cutting tools that are applicable in one technological transition. Under such conditions, the production cycle of the product increases due to frequent tool changes. When providing the required surface profi le, it is mainly required to use equipment with the possibility of multi-axis machining, which leads to an increase in the cost of the product [1–3]. Copy-piercing electrical discharge machining (CPEDM) is widely used to produce complex profi le surfaces. CPEDM allows obtaining the profi le of products of various shapes with minimal expenditures on tools and tooling. Technological transitions do not require the use of special tooling due to the absence of cutting forces in the process of CPEDM [4–7]. The effi ciency of CPEDM depends on the quality of the tool electrode (TE). In modern production, complex profi le EDMs are produced by machining methods (turning, milling). The required surface contour often makes demand for TE that cannot be produced by three-axis machining and then TE is produced on fi ve-axis machining centers with the use of special tooling and cutting tools. These methods of TE manufacturing require signifi cant economic and time expenditures. It is not reasonable to use it within the framework of mass production. For pilot production it is characteristic to produce one test sample for making subsequent changes in its design to minimize the production cycle to ensure the required result. A relevant solution is the production of complex-profi le TE using investment casting technology with obtaining a master model using the rapid prototyping method. The rapid prototyping technology allows producing a prototype of TE to assess the quality and quickly correct the product model. The use of additive technologies to obtain a master model makes it possible to manufacture single TE of diff erent profi les in a short time. Modern equipment used in additive manufacturing allows producing a batch of TE with diff erent profi les in one production cycle, which helps to reduce economic costs and shorten the production cycle [8]. Literature analysis [9–11] showed that it is possible to produce prototypes of products with minimal deviations and structural defects using the technology of rapid prototyping from liquid photopolymers. The application of this technology allows providing the required parameters of repeatable geometry of complex-profi le elements. The works [12–16] note the eff ectiveness of this technology for obtaining the required complex-profi le products. However, the issue of the accuracy of master models obtained by stereolithography has not been fully studied at present. The actual task is the development of scientifi cally substantiated approaches for manufacturing of complex-profi le ET by alternative technologies. The purpose of the work is to ensure the accuracy of manufacturing of complex-profi le TE by casting with the use of rapid prototyping technology for copy-piercing electrical discharge machining. Objectives: 1) to develop a methodology for designing and manufacturing complex-profi le TE for CPEDM using rapid prototyping technology to create a master model; 2) to analyze the shape deviations of a master model made of liquid photopolymer using a coordinate measuring machine (CMM); 3) to perform CAD model correction to reduce the shape deviation of the master model; 4) to develop a sprue-feeding system and evaluate the porosity of the casting during metal pouring; 5) to conduct an experimental study of the accuracy of the CPEDM process of the profi le groove of the TE made by casting with obtaining the investment pattern using the rapid prototyping technology. Research methodology The experiments were conducted on the basis of the Center for Collective Usage of the Department of “Innovative technologies of mechanical engineering” of the Federal Autonomous Educational Institution of Higher Education “Perm National Research Polytechnic University”. Within the framework of the research
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