No abstract

Research evolution timely tendencies, in the nonconventional technologies field, are: manufacture conditions optimization and complex equipments design. The increasing of ultrasonic machining use, in various technologies is due to the expanding need of a wide range materials and high quality manufacture standards in many activity fields. This paper present a experimental study made in order to analyze the welded zone material structure and welding quality. The effects of aluminium ultrasonic welding parameters such as relative energy, machining time, amplitude and working force were compared through traction tests values and microstructural analysis. Microhardness tests were, also, made in five different points, two in the base material and three in the welded zone, on each welded aluminium sample. The aluminum welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara. The ultrasonic welding temperature is lower than the aluminium melting temperature, that's so our experiments reveal that the aluminium ultrasonic welding process doesn't determine the appearance of moulding structure. In the joint we have only crystalline grains deformation, phase transformation and aluminium diffusion.

In this paper the authors present the construction of a modular processing device, fitted by collet mechanisms. A research study of the operation indicators and its specific performance were made for the designed device. In this study the axial errors were eliminated by using a mobile supporting disc, front supported on the collet mechanisms housing, possibly on main shaft. The functionality conditions of the collet mechanisms were established taking into consideration the force transmission ratio and the mechanism efficiency.

Ultrasonic processing proves particularly effective in leading branches of technology, such as: precision mechanics, optics, electrical engineering, nuclear technology etc. High-strength joints, short machining time and low energy consumption are only three of the main ultrasonic welding advantages that determined research intensification in this field. This paper presents experimental data that illustrates the interdependence between some process parameters and their influence on the joint resistance of the copper sheet ultrasonically welded. Due to the surface friction energy, which is generated in the ultrasonic welding process, some intermolecular connections are broken and other are new are created. In order to demonstrate the quality of the ultrasonically welded copper, there were made macro and microstructural analysis that are proving an excellent metallurgical bonding. The results of microhardness tests, that were made in five different points, on each welded copper sample, revealed the ultrasonic welding process quality showing that the welded material hardness doesn't change. The copper welding experiments were made at the National Research and Development Institute for Welding and Material Testing (ISIM) Timişoara.