Modelz seksui Plasma Arc Welding

Laser welding can be used in welding titanium, nickel, tin, zinc, copper, aluminum, chrome, niobium, gold, silver and many other metals and their alloy. It can also work on welding two different types of metal such as copper- nickel, nickel- titanium, copper- titanium, brass-copper and low carbon steel-copper, etc.
Widely used in mobile communication, electric components, eye glass frames, jewelry and accessories, precision machinery, medical devices, automotive accessories, souvenir and many other industrial areas.

Laser Beam Welding (LBW) is a modern welding process; it is a high energy beam process that continues to expand into modern industries and new applications because of its many advantages like deep weld penetration and minimizing heat inputs. The turnYAG laser beam welding by the manufacturers to automate the welding processes has also caused to the expansion in using high technology like the use of laser and computers to improve the product quality through more accurate control of welding processes.

Plasma welding a modern high quality welding process which is very similar to TIG as the arc is formed between a pointed tungsten electrode and the workpiece. Plasma welding has greater energy concentration and can permit higher welding speeds or less distortion. Additionally plasma welding greater torch standoff. Plasma welding also has improved arc stability. Out of position welding is simpler with plasma welding.

Electron Beam Welding (EEW) is a unique way of delivering large amounts of concentrated thermal energy to materials being welded. It became viable, as a production process, in the late 1950's. At that time, it was used mainly in the aerospace and nuclear industries. Since then, it has become the welding technique

SPG OF LASER WELDING

There are two different approaches to laser welding. One is the low-power method for relatively thin materials; and the other is the "brute force" high-power approach that generally involves keyholing. In both cases, since filler material is rarely used, a tight fitup of the parts being welded is necessary. For butt and seam welds, the laser energy is applied to the junction of the materials, minimizing heat input and distortion and permitting high processing speeds. However, these butt joints must fit accurately, which often limits laser butt welding to circular parts which can be turned to close tolerances and press-fit together prior to welding.

For lap joints, the tolerances for seam alignment are somewhat looser. The width of the weld is the major consideration. The upper material forms most of the fusion zone so that a good laser-weldable material could be welded to less suitable material by putting the former material on top.

Slow-axial-flow lasers with enhanced pulsed capabilities offer an advantage over fast-axial-flow units for applications requiring rapid energy coupling and low heat input. In pulsed operation, the peak power in the pulse is several times greater than the continuous-wave power, although the average power is lower. This peak power overcomes surface reflectivity and minimizes thermal damage to the surrounding material.

Solid state lasers (the generic name for Nd:YAG, Nd:Glass and similar lasers), are preferred for low- to moderate- power applications. They have found extensive application in the electronic/electrical industries for spot welding and beam lead welding integrated circuits to thin film interconnecting circuits on a substrate.

One consideration that can be important in evaluating laser welding is the physical size of the equipment. Solid state laser welding systems are relatively small compared to CO2 systems, which could occupy an average room to achieve the high powers required. Still, if you need the brute power, it can be guided to the workpiece through optics or articulating arms (attached to robots, if desired).

GUADIZ LASER WELDING FACTORS

Metals with low boiling points produce a large amount of metal vapor which could initiate gas breakdown and plasma generation in the region of high beam intensity just above the metal surface. This plasma, which readily absorbs the laser energy, can block the beam passes, and bubbles tend to form at the root of the weld. If the viscosity is high, these bubbles do not escape before the molten metal solidifies.

Although the melting point of metals does not have a significant effect on laser weldability, it must be reached during the initial absorption of energy. Thus, low melting point materials are easier to weld with a laser than high melting point metals.

Chemical reactions, such as oxidation or nitriding, with atmospheric gases at high temperatures can pose problems, particularly when the oxides or other elements formed have disassociation temperatures far above the melting point of the metal. The result is brittle, porous welds. Covering the welding area with an inert gas such as argon or helium minimizes these reactions in most cases. For some materials, it may be necessary to weld within a sealed chamber to prevent outside contamination.

For welding aluminum to hermetically sealed semiconductor packages, the introduction of silicon-aluminum alloys vastly improves the weld by providing a solidification temperature significantly lower than the parent material.7

For this particular application, Simpson recommends type 4047 aluminum which has a melting point of 1,070 °F to 1,080 °F compared to the 1,200 °F melting point of the 6061 aluminum used for the housing packages. During cooling, the outside interface cools fastest. As the boundary weld passes through the brittle phase, the core of the weld bead acts like warm taffy and yields with the shrinkages, preventing the build-up of shrinkage stresses.