Ultrasonic welding of thermoplastics causes local melting of the plastic due to absorption of vibrational energy along the joint to be welded. In metals, welding occurs due to high-pressure dispersion of surface oxides and local motion of the materials.. Ultrasonic welding can be used for both hard and soft plastics, such as semicrystalline plastics, and metals. Ultrasonic welding machines
2008  The heat generation has a considerable effect on the quality of part produced as an output of machining. Silva M. B. et al.,1999  stressed that in machining, heat is generated due to the plastic deformation of layer being cut and as well as due to the frictional forces created between the tool/chip and tool/work interface. Hong S. Y.et al.,1999  defined the role of cryogenic cooling in metal cutting, to remove the heat effectively from the cutting zone, hence lowering cutting temperatures, altering the frictional characteristics at the tool/chip interfaces, modifying the properties of the tool and the workpiece material Below is given an account of the heat generation and temperature distribution in
The capacitor is recharged from the DC source through a resistor (Figure 1.2) after each discharge. The successive spark is transferred to the next narrowest gap. The cumulative effect of a succession of sparks spread over the entire work piece surface resulting to its erosion as such this machining process gives to a shape which is more or less similar to that of the
2.4 SPOT WELDING 2.4.1 Principle of Spot Welding Resistive spot welding is a course of during which contacting metallic surfaces are joined by the heat obtained from resistance to electrical present. Work-items are held collectively under strain exerted by electrodes. In general the sheets available are in the range of 0.5 to 3 mm thickness. The strategy makes use of two shaped copper alloy electrodes to pay attention welding present right into a small "spot" and to concurrently clamp the sheets collectively. Forcing a giant present by the spot will melt the metallic and kind the weld.
The chamber contains heated substrate on which thin film deposition is required to take place. The heat energy to the chamber can be either provided by a RF power source, inductive coil or infrared source. At a certain pressure and temperature there occurs a chemical reaction between the gases inside the chamber and vapour deposition takes place resulting in thin film formation over the heated substrate. (1) Materials that are grown can be of various properties
CHAPTER ONE INTRODUCTION 1.1. General Metal forming is the technology used for shaping metal and alloys into useful products by various forming processes such as rolling, extrusion, forging, drawing, sheet metal forming... etc.. The forming process can be carried out on hot, warm and cold working, depending on the recrystallization temperature of deformed materials . A great variety of metallic parts for building sections, aircrafts and automobiles are produced by the forming processes. Sheet metal forming (SMF) is a special type of forming processes in which blanks, with a thickness being much smaller than the other dimensions are formed into desired forms.
4.4 Selection of Type of Joint & Weld Type:- A welding joint is a edge or point where two or more pieces of metal or plastic are joined together. They are formed by welding two or more work pieces according to a particular shape and geometry. Five types of joints referred to by the American Welding Society (AWS): butt, edge, corner, lap, and tee. Butt welds are welds in which two pieces of metal are to be joined, must be in the same plane. These types of welds are used with thin sheet metals that can be welded with a single pass and require only some preparation.
Whose function is to transform the heat from one fluid or solid to another one till that time when the temperature of both the parts become equal. In the heat exchanger the working fluid is separated by the wall which controls the flow of both the fluids and help them to be separated by each other. In present time the heat exchangers are used in the every industry of science and technology like in the chemical plants , boilers, refrigeration system, air conditioning system, domestic A.C system, medical Science,
The principal object of this invention is to provide an improved downhole heating. Down-hole heating tools find usage in several operations in well service. For example, heating the well casing to accelerate the setting time of cement lying between the oasing and the annulus of the well bore. This consists of a down hole heating tool comprising an axially disposed central core composed of metallic tubing of magnetic material such as mild steel and a number of magnetic core elements each comprising of a number of C-shaped laminations. The C-shaped core elements are radially mounted around the core with the open ends of the C facing and in contact with the tubing and have a coil of magnet wire disposed around the tubing between the ends of the magnetic core elements.