One form of welding that is rapidly gaining in popularity as electronics and other devices continue to shrink is the process of micro resistance welding. This process is a thermal process, where the parts to be welded are heated to their melting points at their interface, and thus form one body when the weld cools. This process is nearly identical to the process of normal scale resistance welding although there are several differences and complications. [Read more...]

Laser welding is a high energy beam process and in this regard is similar to electron beam. With that exception they are unlike one another. The energy density of the laser is achieved by the concentration of light waves not electrons. The laser output is not electrical, does not require electrical continuity, is not influenced by magnetism, is not limited to electrically conductive materials and in fact can interact with any material whether it be metal, plastic, wood, ceramic, etc. Finally its function does not require a vacuum nor are x-rays produced. [Read more...]

The development of the GTAW process was accelerated early in 1940. Initially the process was called “Heliarc”, because Helium was used for the shielding gas. Later when argon became widely available the process was renamed tungsten inert gas or “TIG”. Now, it is generally and preferably called gas tungsten arc welding (GTAW), as gases other than argon and helium, which are inert, can be mixed with them. Hydrogen, for example, may be included for its special benefits. [Read more...]

One of the newest and most interesting fields of joining technology is ultrasonic welding. In this process, high frequency vibrations are combined with pressure to join two materials together quickly and securely, without producing significant amounts of heat. These factors give it many advantages over traditional heat based welding techniques. These include the ability to weld metals of significantly dissimilar melting points; metals that normally form brittle alloys at the weld junction; and welds that are in close proximity to heat sensitive components, such as electronics or plastic components. Finally, ultrasonic welds are made without consumables, such as solder or filler that would ordinarily be used for the connection and with far less energy usage than traditional joining techniques. [Read more...]

A lap joint is formed by overlapping two plates and welding them either in the joint where they meet, as is done in GTAW and PAW, or through the top plate and into the bottom plate. This is usually done using either an electron beam or laser welder. Lap joints can be used to weld pieces of dissimilar thicknesses and materials. Lap joints also greatly reduce the number of critical parameters in the weld. Unlike a butt weld, which performs a similar function, the lap joint does not require that the cut faces be perfectly flat and parallel. Rather, in a lap joint, the only critical surfaces are the faces of the parts where they overlap, and the tolerances on this overlap are fairly high. [Read more...]

Tee joints are used when one part must be joined to the center of another part forming a “T”. Like the other types of weld, there are several ways that this joint can be prepared and welded, each with their own benefits and disadvantages. Most methods of welding tee joints involve welding the two joints between the parts, with either a high or low energy density beam. Like the other weld types, there are fundamental differences in the processes used with these two types of weld. [Read more...]

The fifth major type of welding connection is the corner joint. As its name implies, this joint is used to connect two parts together to form a corner. This weld type is extremely useful and can be preformed with either a high or low energy density welder. There are a total of four common sub types of corner joint, each, as usual, with its own advantages and disadvantages. [Read more...]

One of the most common types of weld joints in manufacturing is the butt joint. This joint is formed when the two pieces to be welded are simply placed face to face and the welding head run over it. In the case of GTAW and PAW this joint can only be used on very thin pieces without extensive preparation and the use of filler wire. Both the laser and the electron beam, on the other hand, can butt weld very thick pieces, up to 30 cm for the electron beam. This is accomplished by using the keyhole method, in which the beam is used to bore a path through the piece for itself, allowing it to distribute energy evenly across the joint, regardless of its depth. This makes the electron beam, and to a lesser extent the laser, the ideal welding system for many jobs. [Read more...]

When very thin plates, foils or diaphragms need to be welded, it is often unfeasible to use either a butt joint or even a lap joint, on the grounds that even a minimal amount of power would burn through the pieces. In this case, a flange joint is employed. To create a flange joint, the edges to be welded together are first bent upright for so that when the parts are places together, the faces of the flange are touching and the joint is upright and properly aligned. The laser or electron beam (Low energy density devices are rarely used for this operation) is then run over the joint, melting a relatively large portion of it, making the weld. [Read more...]

Electron beam welding is a phenomena that is thoroughly understood by scientists and engineers that have studied the process in the research lab, but very little information is published for those of us that want to know more about the welding process performed with electron beam energy. [Read more...]