Abstract Ultrasonic metal forming technology has a great potential for highly productive manufacture of miniature parts. Extremely high plasticity can be achieved under the condition of ultrasonic impact loading of the small-height and thin samples (the so-called “ultrasonic dynamic impact effect”). Despite this, the wide use of ultrasonic micro-forming processes is restricted with some technical challenges including, in particular, a short tool-life due to the strong impact forces and severe tribological conditions. In this paper the tool-saving scheme of ultrasonic wibro-impact metal forming is proposed. The workpiece is drawn through the gap between the working ends of two rigidly mounted longitudinal waveguides. The gap width exceeds the amplitude of idle vibrations. This processing scheme prevents direct contact of working surfaces and provides the long service life of ultrasonic tools. The objectives of this work are to study the applicability of the proposed technological scheme for the mass production of precision miniature parts, to determine the conditions for the occurrence of the impact modes in an ultrasonic vibratory system, and to examine the shape accuracy and the microstructure of processed samples. For this purpose a dynamic model of the forced oscillations of two coupled resonant waveguides is developed. The workpiece is considered as a connecting link and also as a technological load. It is shown that the anti-resonant mode of operation of the vibratory system is the most effective. The necessary condition for plastic flow during vibro-impact processing is derived. Recommendations on the design parameters and resonance tuning of the ultrasonic system are given. Applications of the ultrasonic micro-forging technique for sharpening and rounding the edges of flat samples are exemplified. Metallographic research and microhardness tests show extremely high degree of deformation and significant strain hardening of processed metal. The enhanced metal formability with a long service life of ultrasonic tools gives reason to consider the proposed processing technology as a promising method for the mass production of miniature metal parts.

中文翻译：

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具有固定间隙的两个同轴纵向波导的超声微锻造：模型和应用

摘要 超声波金属成形技术在微型零件的高产制造方面具有巨大的潜力。在小高度和薄样品的超声冲击加载条件下，可以获得极高的塑性（即所谓的“超声动态冲击效应”）。尽管如此，超声波微成形工艺的广泛使用受到一些技术挑战的限制，特别是由于强大的冲击力和严重的摩擦条件导致刀具寿命短。本文提出了超声波微冲击金属成形的省刀方案。工件通过两个刚性安装的纵向波导的工作端之间的间隙被拉出。间隙宽度超过空转振动的幅度。这种处理方案可防止工作表面的直接接触并提供超声波工具的较长使用寿命。这项工作的目的是研究所提出的技术方案在精密微型零件的大规模生产中的适用性，确定超声波振动系统中冲击模式的发生条件，并检查形状精度和微观结构。处理过的样品。为此，开发了两个耦合谐振波导的受迫振荡的动态模型。工件被视为连接环节，也被视为工艺负载。结果表明，振动系统的反共振操作模式是最有效的。推导出了振动冲击加工过程中塑性流动的必要条件。给出了对超声系统的设计参数和共振调谐的建议。举例说明了超声波微锻造技术在平面样品边缘锐化和倒圆方面的应用。金相研究和显微硬度测试表明，加工金属具有极高的变形度和显着的应变硬化。超声波工具具有较长的使用寿命和增强的金属成形性，因此有理由将所提出的加工技术视为大规模生产微型金属零件的有前途的方法。金相研究和显微硬度测试表明，加工金属具有极高的变形度和显着的应变硬化。超声波工具具有较长的使用寿命和增强的金属成形性，因此有理由将所提出的加工技术视为大规模生产微型金属零件的有前途的方法。金相研究和显微硬度测试表明，加工金属具有极高的变形度和显着的应变硬化。超声波工具具有更长的使用寿命和增强的金属成形性，这使我们有理由将所提出的加工技术视为大规模生产微型金属零件的有前途的方法。