Keys To Laser Welding Lap And Edge Joints | Laser Focus World
As a practical matter, this physical behavior makes the process very robust and reliable! For especially critical welds, a single large fixture, designed with the weld path machined out, can ensure ideal part fit-up. One commonality of these electron beam welders is that all beam parameters and all mechanical axes are numerically controlled either by a PLC or a CNC. Applications range from fully automated, high productivity and low cost automotive in-line part production to single part batch processes in the high-cost aircraft engine industry at the other end of the industrial spectrum. Figure 3 shows a typical medium-size chamber on a CVE electron beam welding machine. EBW uses a focused beam of electrons, while the laser welding process uses photons to generate heat. As a result, deep-penetration welding is distinguished by great efficiency and fast welding speeds. Optical tools allow for adaptability in welding. It some cases this may need to be even tighter. The medium vacuum process retains most of the advantages of high vacuum welding and with improved production capability. Welding Stainless Steel. The electron beam travels through the abutting surfaces, and the joint surfaces are then progressively fused – creating a weld. Electron beam welding principles and some aspects of the technology, which permits intricate and complex fabrications in various materials and material combinations, are discussed below.
- Electron beam welding working
- Electron beam welding joint design example
- Electron beam welding joint design and construction
- Electron beam welding joint design and safety
- Electron beam welding joint design and supply
Electron Beam Welding Working
Butt welds do not require a chamfer for thicker pieces, T-joints can be welded from a single side with full strength, and lap welds can be welded through the top sheet or along the seam. Standards Met: Customer supplied specifications. Edge Joint & Tier Welds. Therefore, these parameters are tightly controlled in the welding process. A characteristic of this phenomenon is that it allows the unique capability for deep, narrow welds with very small heat affected zones (HAZ) and minimized thermal distortions of welded assemblies (Figure 2). Keep a gap of maximum 0. There are two types of electron guns. Electron Beam welding was developed in the late 1950's, came of age during the 1960's, and today is a tried and true technology that remains unsurpassed for weld penetration, weld purity, and precision repeatability. Equipment Required for Electron Beam Welding (EBW) 3. All grades of steel can be welded, as well as low melting alloys such as aluminum and magnesium, and high melting materials such as Nickel- and Cobalt-based alloys. Flange welding of galvanized material with and without oscillation using Scansonic FSO. Thus, the overall classification of EBW guns can be represented as shown in Fig. This is critical to get the same power density to ensure repeatable results.
Electron Beam Welding Joint Design Example
Again, the weld interface width determines the joint strength, therefore a defocused beam having a larger weld width will have an increased strength. The deflection coils, situated below the focus coil, move the electron beam in circles or more complex patterns for fusion zone improvement when supplied by appropriate voltages and waveforms. This results in a very concentrated (approx. Streamlining the Process. Preheating the components is a common remedy used to substantially reduce hardness increases. DC power is used in the electron beam welding method with 5-30 volts for small equipment and 70-150 volts for large equipment. See list in section 2. That EB welding can accomplish such a feat is due to the physics of the electron beam welding process.
Electron Beam Welding Joint Design And Construction
Pulsed systems are modulated to output a series of pulses with an off time between those pulses. High welding speeds are possible. High voltages are supplied into an electron gun, which then expels a high-velocity stream of electrons with the help of cathodes, anodes, focusing coils, and magnetic fields. The 2-dimensional weld pattern shown in Figure 8, has total weld length of up to 300 inches which introduces a high amount of heat into the plate. Because of the required vacuum, EB welding cannot be performed by hand. The energy density of the electron beam is around 1, 000 times more than that can be achieved from a traditional arc weld. This precise control of the beam allied to accurate manipulation of the workpiece provides a welding process that is readily capable of being fully automated. The indexing table welder design was established as a reliable machine tool for high-volume production of assemblies several decades ago. This is accomplished through an orifice which is large enough for the beam to pass but does not allow significant back diffusion of gases from chamber to the gun column.
Electron Beam Welding Joint Design And Safety
In an electron beam welder electrons are "boiled off" as current passes through a filament which is in a vacuum enclosure. But there are a number of tips and tricks that can be used to ensure that a good weld is achieved, and a high-quality product is produced. Some of the industries benefitting from this include aerospace, automotive, medical, nuclear, oil and gas. This weld requires a low power, defocused electron beam. Also, there is a probability of evaporation of high vapour pressure metals during welding. Tier Joint — Figure 17. This system has the ability to provide various inclination angles to accommodate alterations in joint position for two- and three-layer welds as flange heights change relative to one another. Once melted, the reflectivity is reduced and the thermal conductance of the process progresses to achieve penetration. Deep-penetration welding allows for a single weld to replace multiple welds in different joint designs. Metal to metal contact provided by good quality copper chill bars is essential to control weld puddle contour. The joint can be spot welded or seam welded. This means that controlling the power of the beam and the motion of the part beneath that beam has to occur with some form of automation.
Electron Beam Welding Joint Design And Supply
Most grades of stainless steels can be easily welded with the electron beam and most importantly, the welds are corrosion resistant as the parent material. Turbochargers are employed to pre-pressurize the air going into the diesel engine to higher than atmospheric levels, thus providing more oxygen for the combustion process. This method tends to create voids within the material lattice of the part. Or agitation of the weld pool by weaving the beam may provide the time necessary to help gases escape the weld pool and reduce porosity. Tack welding with the electron beam is generally useful as a fixturing aid. The weld metal in EB welds have mechanical properties normally similar to those of base metal. Let's start with one of the strongest joint designs, the groove joint, and what makes it so "groovy": First, a quick definition: Groove joints or square groove joints are a type of butt joint, with two flat pieces parallel to each other and butted together with a 100% weld joining the two pieces. In these cases performing both types of welding at the same facility streamlines the manufacturing process. This joint design may be used for materials as thin as 0. Running the machine in keyhole mode can penetrate up to 300mm of steel and is known to create stable, good-quality welds for material thicknesses over 200mm. Weld Penetration Depth:. Of course, to take full advantage of all these benefits and to ensure a high-quality, repeatable process, fabricators need to consider how laser welding compares to other fusion welding processes. Beam energy output can be highly controlled and modulated to produce arbitrary pulse profiles. Phases during weld solidification.
The kinetic energy of the electrons is converted to heat energy, which in turn is the driving force for fusion. Don't use bevelled edges and preferably use a whetstone for the careful removal of sharp slivers. Typical examples of high production rate applications include components like gears, frames, steering columns, transmission and drivelling parts of automobiles, thin-walled tubing, welding of high speed steel to bandsaw and power saw blades.
Elmer [45] pointed out that this could substantially vary from operator to operator and from machine to machine. Axial and circumferential welds can be performed with a rotary tilt device that is mounted on top of the x-/y-table. The pins of the implant, shown in Figure 9, need to be welded into the base plate. The distance from the focus surface to the smallest point is called focal length. As with any metal fabrication technology, smart implementation starts with a good understanding of the process fundamentals. If the configuration includes a hollow area, such as the center tap, there will be a problem with trapped air, especially when tight or press fit joint is used. For these small pin diameters it is advantageous to deflect and move the beam in circles electronically rather than mechanically.
Some of the specific industrial applications of EBW include the welding of cluster gears, titanium compressor rotor and power shaft of a gas turbine engine, rocket engine injector made of aluminium alloy 5083, thermionic heating devices and for joining of high temperature metal components like columbium bellows. As with many welding processes, one of the largest obstacles is guaranteeing that the energy used for joining is accurately positioned in the joint. Distortion that may show up in the workpiece does not necessarily impact the finished quality due in part to the adaptive nature of the process. 82 × 10-12 mm and a mass of 9. Inspection Techniques. Geometry limited applications. Figure 4 shows a typical fixture design. Fusion Welding Comparison.