OBRABOTKAMETALLOV Vol. 26 No. 4 2024 TECHNOLOGY the heat source and wire feed system combined with additional machining [25]. Other related processes in which a plasma torch is used instead of GTAW are Hybrid Plasma Deposition and Milling (HPDM) and Micro Plasma Arc Welding rapid prototyping (MPAW) [26, 27]. In all the metal deposition processes discussed above, precise layer height control remains a challenge due to the wavy nature of multi-pass deposition. To obtain components with precise layer thickness, some researchers have combined milling and deposition [4–6, 25]. These hybrid processes perform a surface milling operation after each layer to ensure z-accuracy. 3D welding and milling developed by [4, 5] combine GMAW deposition with a conventional milling process to produce injection molding inserts [7–12]. In the works [28–30] it is proposed to additionally use ultrasonic processing of products obtained by WAAM technology. According to the authors, this will improve the mechanical properties of the grown products. Many parameters of ultrasonic additional processing in the WAAM process have not yet been optimized and depend on the type of equipment, frequency, amplitude, etc. At the same time, the integration of traditional subtractive technologies with WAAM can provide improved material and energy savings compared to pure subtractive approaches. In fact, WAAM components typically exhibit high structural integrity when the process parameters are optimized, so only machining operations need to be performed. In addition, very little surface deformation depth is expected with the hybrid technology. The synergistic integration of the surfacing unit with the CNC machine, regardless of its brand and age, is a key aspect in the hybrid technology. The integration should be done in a way that surfacing can act as an additional function without disturbing other capabilities of the CNC machine. During the integration, changes to the mechanical and electrical systems are made without the need for any proprietary information from the machine manufacturer or the control system designer. There are mechanical challenges: the fi rst is to mount the welding torch on the side of the spindle so that surfacing is controlled through the same CNC controller; the second is to select a suitable mechanism to remove the excess heat generated during welding; the third is to take appropriate precautions to protect the machine components from accidental splashes. Electrical and control problems arise separately: 1) switching on/off the welding and surfacing unit via the CNC program; 2) simple and fast switching between surfacing mode and normal CNC mode; 3) elimination of any direct electrical contact between the CNC controller and the welding unit. It is important to understand that serial equipment for the implementation of complex (hybrid additive technology) is not yet manufactured, and all work performed in this area is associated with the modernization of CNC machines, which is not always justifi ed from an economic point of view. A relatively simple methodological point of view and minimal fi nancial costs for equipment is an approach based on the separate use of WAAM technology with other processing methods that are available for a wider range of studies, in order to study the properties of the obtained materials. This paper presents a study of the characteristics of metal processing applied by the WAAM method with additional mechanical and ultrasonic processing. The aim of the work is to evaluate the quality and mechanical properties of the obtained metal layers from low-carbon steel using the WAAM method with the use of additional mechanical and ultrasonic processing. Materials and research methods A single-phase inverter device KEMPPI Kempomat 1701 was used as a power source for mechanized surfacing in a protective gas environment. A mixture of argon (80 %) and CO2 (20 %) was used as a shielding gas. Welding wire Sv-08G2S (0.08 C-2 Mn-Si) with a copper coating of 1.0 mm in diameter was used. The parameters of the layer growth process (Fig. 1, a) were determined to ensure optimal productivity and cooling time between successive layer depositions. The number of passes was determined to be 5. After each pass, mechanical processing of the surface of the surfaced bead was carried out. Then, visual inspection was carried out and a magnifying glass (ten-power magnifi cation) was used to assess the surface quality. After the inspection, a new layer was surfaced (Fig. 1, b).
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