Here a steam of high speed electrons impinges on the work surface so that the kinetic energy of electrons is transferred to work producing intense heating. InLi et al. In all these applications the process proved to be robust and flexible at the same time. So EBM is not suitable for large work pieces.
Welding of low melting alloys, like aluminum or magnesium, may initially be a challenge as the high beam power concentration easily can overheat the material possibly resulting in porosity in the weld, rough top beads and splatters.
The materials range from low carbon sheet metal for clutch carriers to medium carbon, micro alloyed steels for shafts. A challenge greater than the sheet metal design is posed by joint segments with varying thicknesses that require a change of power not only at the beginning and the end of the joint but also in between.
Since the majority of applications need axial or circumferential welds, multiple part holders should be used whenever possible in order to make the process more cost effective.
YAG lasers with a pulse duration of a few tens of nanoseconds are utilized, a single laser pulse will typically vaporize the surface material to a depth of 0. Critical to this application is a partial, constant weld penetration to prevent a breakthrough of the beam and keep the front of the implant absolutely vapor and splatter free.
Special circumstances may require conduction mode welding as opposed to key-hole welding that typically produces wide and shallow welds.
Different types of electron beam welders have evolved over the years influenced by the market to address specific needs from both a technical and economical perspective. The vapor from the source condenses onto a substrate, creating a thin film of high-purity material.
Pattern Generator - A Unique Welding Parameter Narrow and deep welds are typically more subject to porosity, most often at the root but also in the middle of the weld.
As a practical matter, this physical behavior makes the process very robust and reliable! This is achieved by appropriately biasing the biased grid located just after the cathode.
Electron-beam welding Since the beginning of electron-beam welding on an industrial scale at the end of the s, countless electron-beam welders have been designed and are being used worldwide.
Weld cross sections of production parts will be shown to demonstrate obtainable weld shapes. It has become common practice in the automotive industry to preheat gears prior to welding in order to reduce the quenching effect in the HAZ. This technique is used in microelectronicsoptics, and material research, and to produce solar cells and many other products.
Workpiece material should be electrically conducting. Bone bonding strength and histological bone in-growth were evaluated after 4 and 12 months of implantation, and it was found that the potential application of EBM-fabricated parts could be as acetabular cups.
Due to the physical nature of the electrons - charged particles with an extremely low mass - their direction of travel can easily be influenced by electromagnetic fields. Recent machine developments make it possible even to go up to kHz.
As the electron beam is moved forward, material melts at the front of the beam. This type of welder typically employs a 2-station dial index with one part in each of the stations.
Electron beam welders use this characteristic to electromagnetically focus and very precisely deflect the beam at speeds up to 10 kHz. Film thicknesses from a single atomic layer to many micrometers can be achieved. For mass production of steels, large furnaces with capacity measured in metric tons and electron-beam power in megawatts exist in industrialized countries.
Process[ edit ] The EBM beam is operated in pulse mode. Mechanism[ edit ] Free electrons in a vacuum can be manipulated by electric and magnetic fields to form a fine beam.
The choice of wavelength depends on the minimum structure size and the optical properties of the substrate material, such as absorption and reflection characteristics. The kinetic energy is transformed into thermal energy at or near the surface of the material.
Machining applications of laser include drilling, cutting, engraving, marking, and texturing. Finally, a regression equation was developed from the experimental results that can be used to predict the fatigue life of the designed dental abutment.
Most significantly, laser machining can remove materials in small amounts with a small heat-affected zone. Depending upon the intensity of heating the workpiece can melt and vaporize. Again, a deflection pattern in combination with a continuous adjustment to beam power permits the development of a robust set of welding parameters that hold up in daily production on the manufacturing floor.
The disadvantage of laser machining is the re-deposition of substrate material, which makes the quality control of the machined surfaces difficult. Physical-vapor-deposition solar-cell production[ edit ] Physical vapor deposition takes place in a vacuum and produces a thin film of solar cells by depositing thin layers of metals onto a backing structure.
Laser micromachining is suitable for fabrication of microchannels and fluidic access holes. The electron lithograph is also used to produce computer-generated holograms CGH.Overview & Our History.
EXCEPTIONAL ENGINEERING To focus our marketing and capabilities on electron beam devices such as Traveling Wave Tubes (TWT’s), Accelerators, and X-ray Tubes.
Altair is the only known Contract Brazer: “machining’ and “engineering. Oct 28, · On this channel you can get education and knowledge for general issues and topics. Electron-beam machining (EBM) is a process where high-velocity electrons concentrated into a narrow beam are directed toward the work piece, creating heat and vaporizing the material.
EBM can be used for very accurate cutting or boring of a wide variety of metals. Electron beam melting and refining (EBMR) in a vacuum using an intense electron beam is a widely used, ecologically-friendly method.
The electron beam melting and refining of metals is accomplished using electron beams as a heating source in a vacuum chamber with a vacuum pressure of (5–8)×10 3 Pa. Abstract.
This paper provides a technical overview of the unique features of the electron beam welding process including several applications. Weld cross sections of production parts will be shown to demonstrate obtainable weld shapes. Laser Beam Machining.
Laser beam machining (LBM) is a thermal energy based advanced machining process in which the material is removed by (i) melting, (ii) vaporization, and (iii) chemical degradation (chemical bonds are broken which causes the materials to degrade).Download