Glossar
A
- Acceleration voltage
High voltage potential between cathode and anode which accelerates the electrons into a beam.
Air-lock machineEB welding machine with a separate chamber partition for loading/unloading in order to eliminate the evacuation time by operating parallel to processing time.
AnodeGrounded electrode within the beam generation system, forming an electrical potential with the cathode.
AtmosphereFree atmosphere at 1 atm pressure surrounding the beam generator and the workpiece to be welded in Non-vac or In-air processing.
AutomationEBW machines run fully automatic. For mass production they can be automatically linked to other equipment for pre and post EB process operations.
B
- Bead on plate weld
Simulated welding run into material with no joint.
Beam adjustmentMagnetic alignment of the beam axis relative to the focus coil axis centre-line.
Beam currentElectrical current(measured in amps) flowing in the electron beam.
Beam energyKinetic energy of the electrons impinging the workpiece; a product of the elementary charge and the accelerating voltage. Sometimes confused with the term - beam power.
Beam generatorSource of an electron beam.
Beam powerProduct of beam current (mA) and high voltage (kV), measured in kilowatts (kW).
Beam profileEnvelope of the electron beam as it traverses its way from the beam generator to the workpiece.
C
- Cathode
Electron emitter; part of the beam generator. It is heated to very high temperatures to free electrons from its surface and is connected to the negative high-voltage potential.
Chamber machineBasic type of an EB welding machine having a suitably designed working chamber which can accessed by an opening and closing door.
CleaningAny kind of contamination of the parts to be welded will adversely affect the weld quality; therefore cleaning prior to welding is an essential step.
ConsumptionEB welders need (only) electric energy from supply for operation; compressed air in low amount is used for valve operation.
ControlEB machines and processes are CNC or PLC controlled.
CosmeticsShallow welding run (with adapted parameters) to reduce or smooth-the crown or root part of the penetration weld.
Cycle timeTotal time to perform a complete EB machine’s work-cycle, independent of the number of parts processed in doing so.
D
- Deep welding effect
The extreme high power density of the beam not only melts the workpiece metal but also evaporates it locally and forms a key hole. By this means the beam penetrates into the material up to a depth controlled by the parameters used. In moving the beam along the path a deep weld is performed from the solidifying the molten material behind the key-hole.
DeflectionThe beam of electrons can be deflected by magnetic (and/or more seldom electric) fields which are regulated by the machine’s control.
Deflection gridDigital array of deflection positions which the beam can target on the workpiece.
Deflection patternDigital or analogue figure which can be transposed by beam onto the workpiece.
Deflection systemSystem of magnetic coils and controlled constant current sources which produce static or dynamic beam deflection movement.
DeformationThermal distortion of the workpiece; a result of high energy input.
E
- EB
Abbr.: electron beam
EB brazingelectron beam brazing
EB drillingelectron beam drilling
EB generatorelectron beam generator
EB machineelectron beam machine
EB treatmentelectron beam treatment
EB weldingelectron beam welding
ElectronElementary particle having a mass of 9.1 x 10-28 g and carrying an negative electrical charge of 1.6 x 10-19 As.
Electron beamParticle beam produced by a generator to process metallic materials.
Electron beam brazingFusion brazing by using the heat from an impinging electron beam.
Electron beam drillingPerforation of metallic material by means of single eb-pulse percussion processing [material ejected from eb-pulse generated key-holes].
Electron beam generatorSelf-contained unit, forming part to an EB welding machine, which develops the electron beam.
Electron beam generatorSelf-contained unit, forming part to an EB welding machine, which develops the electron beam.
Electron beam hardeningA special process to locally transform the surface by means of an electron beam – with the objective of increasing the hardness (especially without melting the surface). Self quenching is performed without any additional cooling process.
Electron beam machineMachine for processing any work by means of an electron beam.
Electron beam treatmentProcessing any work by means of an electron beam.
Electron beam weldingFusion welding by using the heat from an impinging electron beam.
Energy inputAmount of beam energy transformed into heat within the workpiece.
Evacuation timeTime to achieve operating pressure.
F
- Fast beam deflection
High-speed magnetic deflection of an electron beam. Point-to-point frequencies up to 1 MHz.
Feasibility of weldingProperty of a given metal or metal combination to achieve successful fusion welding without unacceptable inclusions.
Filler materialAdditional metal (generally in wire form) to fill gaps or to alloy the weld zone material.
Floor-to-floor timeTime to process one (1) workpiece from a machine or production line – used in mass production.
FocusPlane of an electron beam where its diameter is at a minimum.
Focus coilCurrent-current torriodial coil; producing a magnetic focus effect on the electron beam.
FocussingSee: focus coil
G
- Gun column
Colloquial term for electron beam generator.
H
- Hardening
Transformation of steel or cast iron microstructure to martensite.
I
- Indexing machine
High volume production EB machines equipped with an indexing table carrying a minimum of two stations for loading/unloading and processing, respectively.
InterlinkingThis means the automated integration of an EB welding machine to other equipment within a production line.
J
- Job shop
Plant for sub-contract electron beam production, for both one off and mass production.
Joint preparationParticularly the form of the joint edges. Most common type used in EB welding is a butt joint with theoretical zero-gap.
K
- Key hole
Metal-vapour gas capillary opening developed in deep welding processing.
M
- Magnetic lens
See: focus coil
Mass productionHigh volume production achieved by EB processing with minimum down times.
Material assemblyEB welding is able to join dissimilar materials.
MetallurgyThe resultant microstructure resulting from the fusion process created by the electron.
MicrostructureComposition and configuration of the basic elements within a metallic alloy or compound.
N
- NonVac
Abbr.: Nonvacuum electron beam welding
Nonvacuum electron beam weldingApplication of an electron beam (generated in a high-vacuum unit) out of vacuum, i.e. in free atmosphere.
O
- Observation
The process area can be observed by means of light-optical systems (via TV camera) or by using reflected electrons from a scanned beam.
Operation costsLow operation costs are a general characteristic of EB machines.
P
- Production cell
EB machine interlinked to other operating units within a production cell.
Production lineEB machine interlinked to other operating units within a production line.
Protection gasIn contrast to all other fusion welding processes EB welding does not need any gas to protect weld metallurgy.
Pumping unitEquipment to develop a vacuum within the EB machine, in order to develop and weld with the electron beam.
Q
- Quality
In particular the properties of any EB processing. Quality levels are defined in certain norms.
R
- Radiological protection
EB produces unwanted X-rays as a by-product. Human have to be protected from high levels of X-radiation, this is achieved within the EB-machine’s design concept.
Rotary indexing machineSee: indexing machine
S
- Single-item production
Complex and expensive parts are processed as single processes in direct contrast to mass production.
SmoothingSee: cosmetics
Surface modificationBy local heat treatment – without or with melting the surface – the EB can change the metallurgical structure within a certain depth of the surface. This includes hardening, remelting, alloying, embedding, structuring etc.
T
- Technology
A set of parameters used within a special process or application.
V
- Vacuum
In order to avoid scattering of the electrons by gas molecules the beam generator (~10-4 mbar) as well as the working chamber (10-2 to 10-6 mbar) are evacuated.
Vacuum chamberSee: working chamber
W
- Waist of beam
In contrast to a laser beam, the electron beam is not focussed to a precise level (a point) but exhibits a focus-waist (a few millimetres in length). EB processes are therefore less sensitive to small tolerances in working distance.
Wall-plug efficiencyThe effectiveness of converting electrical energy into thermal welding power.
Wehnelt electrodeThis solid grid cup (placed between cathode and anode within the beam generating system) controls the beam current by means of its negative field-potential.
Weld depthThe penetration depth of the key-hole determines the depth of the achievable weld.
Weld profileThe shape and form of the solidified metal seen in a transverse weld cross-section. The two fusion faces (flanks) of EB welds are typically parallel; therefore reducing the angular shrinkage and workpiece distortion.
Weld withMeasure of the distance between the two fusion faces of a weld profile.
WeldingIn particular, processes and their result within the solidified melting pool with respect to the composition and properties of the weld metal.
Welding technologyIn particular, whole set of parameters used in a special welding task.
Working chamberEvacuated chamber of an EB machine where the EB process takes place.
X
- X-rays
Short-wave electromagnetic radiation which occurs parasitically with any electron beam process. Its “hardness” (ability for penetration) increases with the level of the accelerating high voltage.