The Superposition of Longitudinal Sonic Oscillations on the Wire Drawing Process

Abstract
Part 1: Characteristics of complete wire drawing apparatus Part 1 describes the wire drawing machine, instrumentation and oscillatory apparatus designed to establish the effects of applying oscillatory energy to the wire drawing process. A theoretical consideration of the vibration of the equipment is included and compared with experimental data. Tests were performed on a 3000 lbf bull-block and the oscillatory energy was supplied in a longitudinal mode from a 3000 lbf electro-hydraulic oscillator. Equipment was designed to measure drawing force, drawing torque, amplitude of die and drum oscillation, and drawing speed. Frequencies of die oscillation in the range 0–125 Hz were studied with amplitudes up to 0.070 in peak to peak. A study of process parameters, such as natural frequency of the system, damping of the bull-block drive, torsional oscillation of the drum, and die assembly inertia, showed that the analysis was in good agreement with experimental data and that it can be used to predict the effect of oscillations on the forces and torques acting during oscillatory wire drawing. Part 2 presents experimental data obtained from mild steel, hard aluminium, stainless steel and hard copper. Results show that there is no reduction in the peak drawing force and negligible reduction in the coefficient of friction. The results also confirm that oscillatory drawing is a mechanical process of straining and unstraining the drawn wire, and that the reduction in mean force can be determined by a mechanism of force superposition.
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