OBRABOTKAMETALLOV Vol. 26 No. 1 2024 TECHNOLOGY Fig. 1. Machine for wire-arc additive manufacturing on the basis of CNC machine: 1 – frame; 2 – linear guides; 3 – stepper motor; 4 – CNC machine table; 5 – rotary table; 6 – Z-axis module; 7 – feeding mechanism; 8 – control unit; 9 – coil; 10 – electromagnet To create a longitudinal magnetic fi eld, an electromagnet was used; its steel core had an internal diameter of 20 mm, a wall thickness of 4 mm; a winding was made of PETV-2 wire with a diameter of 0.72 mm with a number of turns of 1,200. Preliminary, it was found out experimentally that the surfacing process runs stably when the electromagnet is connected to an alternating sinusoidal current with a frequency of 50 Hz and a voltage of 30 V; the initial height of the magnet above the backing was 10 mm, so further, surfacing of specimens was carried out in these modes. The measurement carried out using a portable universal TPU milliteslameter showed that under these modes of applying electromagnet at a melting point of the wire, the magnetic induction does not exceed 5.7 mT. When studying the infl uence of a longitudinal magnetic fi eld on the dimensions of single layers, six specimens were surfaced: three specimens were deposited without the infl uence of a longitudinal magnetic fi eld and three ones were surfaced when the electric arc was exposed to a magnetic fi eld created by an inductance coil. The surfaced specimens were cut in three places and preliminarily cleaned along the cut plane. The dimensions of single layers, its width and height, were measured using an MPB-2 microscope at 24-fold magnifi cation with a scale value of 0.05 mm (fi g. 2). a b Fig. 2. Cross-section of single surfaced layers: a – without longitudinal magnetic fi eld; b – with longitudinal magnetic fi eld
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