In accordance with one or more embodiments herein, an additive manufacturing apparatus (100) is provided. The additive manufacturing apparatus (100) comprises a particle beam source (110), a build tank (150), a vacuum chamber (130), arranged to enclose the particle beam all the way from the particle beam source (110) to the build tank (150), one or more vacuum pumps (140), arranged to provide vacuum inside the vacuum chamber (130), and an X-ray shield (120), arranged to enclose at least the particle beam source (110), the vacuum chamber (130), and at least one of the one or more vacuum pumps (140). Further, a method (400) for constructing an additive manufacturing apparatus comprising a particle beam source (110) and a build tank 150 is provided. The method (400) comprises arranging (410) an X-ray shield (120) in an additive manufacturing apparatus (100), to enclose at least the particle beam source (110), a vacuum chamber (130) arranged to enclose the particle beam all the way from the particle beam source (110) to the build tank (150), and at least one vacuum pump (140) arranged to provide vacuum inside the vacuum chamber (130).
B22F 10/28 - Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
B22F 12/00 - Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
B22F 12/82 - Combination of additive manufacturing apparatus or devices with other processing apparatus or devices
B22F 12/90 - Means for process control, e.g. cameras or sensors
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
G21F 1/08 - Metals; Alloys; Cermets, i.e. sintered mixtures of ceramics and metals
G21F 3/00 - Shielding characterised by its physical form, e.g. granules, or shape of the material
A metal 3D printer, a cathode holder system, a carrier for an electron emitter, and an electron source piece with a thermal break in a mechanical interface are provided. The metal 3D printer has an electron gun adapted to direct an electron beam generated by a back heated electron emitter of a cathode arrangement onto a metal material via an anode arrangement. The back heated electron emitter is capable of emitting electrons via thermionic emission from an emitting surface when heated on a back surface, and includes a side surface, essentially perpendicular to the emitting surface, between the emitting surface and the back surface. The metal 3D printer 100 includes: an electron source piece, including the electron emitter attached to a carrier in such a way that the carrier covers the side surface of the electron emitter adjoining the emitting surface; a cathode holder system including one or more cathode holder system members adapted to hold the electron source piece in a position in relation to an anode arrangement; and a first thermal break in a first mechanical interface adapted to mate an emitter holder of the cathode holder system with the electron source piece.
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
H01J 37/075 - Electron guns using thermionic emission from cathodes heated by particle bombardment or by irradiation, e.g. by laser
B22F 12/41 - Radiation means characterised by the type, e.g. laser or electron beam
H01J 37/305 - Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
An arrangement for additive manufacturing by selective fusion of layers of a three-dimensional product from a powder bed including successively formed powder layers is provided. The arrangement includes a heating element having a powder layer facing surface, arranged in a powder layer heating position above a powder layer, in such a way that heat radiation emitted from said heating element heats at least a part of the powder layer before the selective fusion of a layer of the three-dimensional product from the powder layer.
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
A method for removing powder from a component or part produced by a powder bed additive manufacturing system is provided. The method includes providing a part, the part having at least one internal cavity with at least one external opening, the at least one cavity being at least partly filled with powder grains, the powder grains being connected to each other and to the walls of the cavity by mechanical, frictional, electrical, physical, or chemical forces. The method further includes adding medium in liquid phase to the at least one cavity of the part, the liquid having the property that it expands in phase transition from liquid to solid phase; transforming added medium to solid phase to loosen and break up at least a fraction of the powder grains connections from each other; and removing powder from the at least one internal cavity.
B08B 3/12 - Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
B33Y 40/20 - Post-treatment, e.g. curing, coating or polishing
B08B 7/00 - Cleaning by methods not provided for in a single other subclass or a single group in this subclass
B29C 71/00 - After-treatment of articles without altering their shape; Apparatus therefor
The present invention relates to a heating method for preparing a powder bed for subsequent processing by irradiating the powder bed with an electron beam from an electron source. The electron source may be designed for fast moving of the electron beam to different heating positions at the powder bed comprising the step, local heating of at least two powder bed heating positions by successive resting of said electron beam at the at least two powder bed heating positions. By jumping between local preheating positions at the powder bed before the powder is fused, charged powder can be prevented from levitation and scattering from the powder bed.
The present invention relates to an apparatus and a method for an electron beam system for manufacturing a three-dimensional object by fusing successive layers of powder, said system having at least one lens for reshaping of said electron beam, an electron source and a powder bed, said method comprising the step: blocking a selected cross section of said electron beam for controlling the electron beam power. By interference between the electron beam and a beam blocking part a portion of the electron beam is prevented from reaching the powder bed.
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
09 - Scientific and electric apparatus and instruments
Goods & Services
(Based on 44(e)) 3D printers (Based on 44(e)) Laboratory apparatus and instruments, namely, electron beam accelerators; Laboratory apparatus and instruments, namely, vacuum chambers, recoating mechanisms and adaptable powder feeding mechanisms for additive manufacturing using metal powder; all of the foregoing for laboratory use
40 - Treatment of materials; recycling, air and water treatment,
Goods & Services
Machines and machine tools for treatment of materials and for manufacturing, namely, machines and machine tools for additive manufacturing using metal powder Metal treatment, namely, shaping of metal components
In accordance with one or more embodiments herein, an arrangement 200 for additive manufacturing by selective fusion of layers of a three-dimensional product from a powder bed comprising successively formed powder layers 240 is provided. The arrangement 200 comprises a heating element 350 having a powder layer facing surface 355, arranged in a powder layer heating position above a powder layer 240, in such a way that heat radiation emitted from said heating element 350 heats at least a part of the powder layer 240 before the selective fusion of a layer of the three-dimensional product from the powder layer 240.
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
B23K 26/00 - Working by laser beam, e.g. welding, cutting or boring
In accordance with one or more embodiments herein, an arrangement 200 for additive manufacturing by selective fusion of layers of a three-dimensional product from a powder bed comprising successively formed powder layers 240 is provided. The arrangement 200 comprises a heating element 350 having a powder layer facing surface 355, arranged in a powder layer heating position above a powder layer 240, in such a way that heat radiation emitted from said heating element 350 heats at least a part of the powder layer 240 before the selective fusion of a layer of the three-dimensional product from the powder layer 240.
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
B23K 26/00 - Working by laser beam, e.g. welding, cutting or boring
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
The present invention relates to a build compartment used in 3D printing systems based on powder beds. The build compartment is the volume in a 3D printing apparatus where 3D objects are formed by successive consolidation of thin layers of powder. The build compartment is designed with at least two vertical wall structures movable in relation to each other. The movable wall structures are at least partly overlapping in the movable direction, providing self-sealing for a variable volume for enclosing powder. Contrary to other available designs, this solution does not need a compressible sealing material, for example an elastomer, a textile felt or a braided rope, to prevent powder leakage from the build compartment. The advantages are more reliable sealing and no risk of contamination of the powder by debris from sealing material.
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
B29C 64/255 - Enclosures for the building material, e.g. powder containers
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
09 - Scientific and electric apparatus and instruments
40 - Treatment of materials; recycling, air and water treatment,
Goods & Services
Machines and machine tools for treatment of materials and for manufacturing. Electron beam accelerators; Laboratory apparatus and instruments. Shaping of metal components.
17.
Freezing method for cleaning an additive manufacturing part
The present invention relates to a method for removing powder from a component or part produced by a powder bed additive manufacturing system. The method comprises the steps; providing a part, the part having at least one internal cavity with at least one external opening, the at least one cavity being at least partly filled with powder grains, the powder grains being connected to each other and to the walls of the cavity by mechanical, frictional, electrical, physical or chemical forces; adding medium in liquid phase to the at least one cavity of the part, the liquid having the property that it expands in phase transition from liquid to solid phase; transforming added medium to solid phase to loosen and break up at least a fraction of the powder grains connections from each other; and removing powder from the at least one internal cavity.
B08B 3/12 - Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
B08B 7/00 - Cleaning by methods not provided for in a single other subclass or a single group in this subclass
B29C 71/00 - After-treatment of articles without altering their shape; Apparatus therefor
B33Y 40/20 - Post-treatment, e.g. curing, coating or polishing
A method for manufacturing a three-dimensional object by solidifying selected areas of consecutive powder layers is provided. At least one electron beam successively irradiates predetermined sections of each powder layer by moving an interaction region in which the electron beam interacts with the powder layer. Electromagnetic radiation from a radiation source is directed onto the powder layer to reduce local electrostatic charging in the interaction region. In this way, levitation and scattering of charged powder will be avoided.
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
B29C 64/277 - Arrangements for irradiation using multiple radiation means, e.g. micromirrors or multiple light-emitting diodes [LED]
B29C 64/273 - Arrangements for irradiation using electron beams [EB] frequency modulated
B29C 64/188 - Processes of additive manufacturing involving additional operations performed on the added layers, e.g. smoothing, grinding or thickness control
A metal 3D printer, a cathode holder system, a carrier for an electron emitter, and an electron source piece with a thermal break in a mechanical interface. The metal 3D printer has an electron gun adapted to direct an electron beam generated by a back heated electron emitter of a cathode arrangement onto a metal material via an anode arrangement. The metal 3D printer comprises: an electron source piece, comprising the electron emitter attached to a carrier such that the carrier covers the side surface of the electron emitter adjoining the emitting surface; a cathode holder system comprising one or more cathode holder system members adapted to hold the electron source piece in a position in relation to an anode arrangement; and a first thermal break in a first mechanical interface to mate an emitter holder of the cathode holder system with the electron source piece.
B22F 12/41 - Radiation means characterised by the type, e.g. laser or electron beam
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
B22F 10/28 - Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
A metal 3D printer (100), a cathode holder system (112), a carrier (300) for an electron emitter (312), and an electron source piece (114) with a thermal break in a mechanical interface are provided. The metal 3D printer (100) has an electron gun adapted to direct an electron beam (102) generated by a back heated electron emitter (312) of a cathode arrangement (106) onto a metal material via an anode arrangement (110). The back heated electron emitter (312) is capable of emitting electrons via thermionic emission from an emitting surface (314) when heated on a back surface (316), and comprises a side surface (315), essentially perpendicular to the emitting surface (314), between the emitting surface (314) and the back surface (316). The metal 3D printer (100) comprises: an electron source piece (114), comprising the electron emitter (312) attached to a carrier (300) in such a way that the carrier (300) covers the side surface (315) of the electron emitter (312) adjoining the emitting surface (314); a cathode holder system (112) comprising one or more cathode holder system members (120, 126, 130) adapted to hold the electron source piece (114) in a position in relation to an anode arrangement (110); and a first thermal break in a first mechanical interface (310) adapted to mate an emitter holder (120) of the cathode holder system (112) with the electron source piece (114).
H01J 37/305 - Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
A cathode assembly for emitting charged particles, used in for example an electron gun as source for generating an electron beam is provided. The cathode assembly has a cathode including an emitting member and a carrier. The emitting member is mounted in the carrier, and the carrier is electrically connected to a holder. The cathode is heated by irradiation from an external source, whereby the emitting member emits charged particles from an emitting surface at an emitting temperature. The connection between the carrier and the holder provides a thermal barrier for reducing the amount of thermal energy transferred from the cathode to the holder.
A method for removing powder from a component or part produced by metal additive manufacturing systems based on powder beds. The method includes manufacturing a part by additive manufacturing, the part having at least one internal cavity with at least one external opening. The internal cavity is at least partly filled with powder, the powder in the internal cavity having grains agglomerated or connected to each other. The method further including: evacuating gas from the internal cavity; adding liquid electrolyte to the internal cavity, and using an electrochemical process for separating connected powder grains in the cavity.
The present invention relates to an apparatus and a method for an electron beam system for manufacturing a three-dimensional object by fusing successive layers of powder, said system having at least one lens for reshaping of said electron beam, an electron source and a powder bed, said method comprising the step: blocking a selected cross section of said electron beam for controlling the electron beam power. By interference between the electron beam and a beam blocking part a portion of the electron beam is prevented from reaching the powder bed.
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
B33Y 50/02 - Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
B29C 64/273 - Arrangements for irradiation using electron beams [EB] frequency modulated
The present invention relates to an apparatus and a method for an electron beam system for manufacturing a three-dimensional object by fusing successive layers of powder, said system having at least one lens for reshaping of said electron beam, an electron source and a powder bed, said method comprising the step: blocking a selected cross section of said electron beam for controlling the electron beam power. By interference between the electron beam and a beam blocking part a portion of the electron beam is prevented from reaching the powder bed.
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
B33Y 50/02 - Data acquisition or data processing for additive manufacturing for controlling or regulating additive manufacturing processes
H01J 37/24 - Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for
H01J 37/305 - Electron-beam or ion-beam tubes for localised treatment of objects for casting, melting, evaporating, or etching
The present invention relates to a heating method for preparing a powder bed for subsequent processing by irradiating the powder bed with an electron beam from an electron source. The electron source may be designed for fast moving of the electron beam to different heating positions at the powder bed comprising the step, local heating of at least two powder bed heating positions by successive resting of said electron beam at the at least two powder bed heating positions. By jumping between local preheating positions at the powder bed before the powder is fused, charged powder can be prevented from levitation and scattering from the powder bed.
The present disclosure relates to 3D printing systems based on powder beds, in which 3D objects are formed by successive consolidation of thin layers of powder (205). Specifically, it relates to a powder compartment from which powder feedstock is distributed in a 3D printer. The powder compartment has at least two wall structures movable in relation to each other, said wall structures being at least partly overlapping in the movable direction, providing a variable volume for enclosing powder. The powder compartment having at least two vertical wall structures (201, 202) movable in relation to each other. The movable wall structures being at least partly overlapping in the movable direction, providing a variable volume for enclosing powder. Contrary to other available designs, this solution does not need a compressible sealing material, for example an elastomer, a textile felt or a braided rope, to prevent powder leakage from the powder compartment. The benefits are a simple and robust design providing more reliable sealing and no risk of contamination of the powder by debris from sealing material.
B29C 64/255 - Enclosures for the building material, e.g. powder containers
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
B33Y 40/00 - Auxiliary operations or equipment, e.g. for material handling
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
B29C 64/165 - Processes of additive manufacturing using a combination of solid and fluid materials, e.g. a powder selectively bound by a liquid binder, catalyst, inhibitor or energy absorber
B22F 3/105 - Sintering only by using electric current, laser radiation or plasma
The present invention relates to a circuit arrangement comprising an analogue amplifier electrically connected to a first end of an inductive load. Further at least one electrical switch is electrically connected to a second end of the inductive load, where the electrical switch increases the rate of current change in the inductive load by applying an electrical voltage potential to the second end of the inductive load. The voltage at the second end can also be switched by a digital circuit at the second end for improved performance. The inductive load may e.g. be a beam control coil, which may be provided for controlling an electron beam, e.g. in an electron gun.
H03F 1/56 - Modifications of input or output impedances, not otherwise provided for
H05G 1/58 - Switching arrangements for changing-over from one mode of operation to another, e.g. from radioscopy to radiography, from radioscopy to irradiation
The present invention relates to a build compartment used in 3D printing systems based on powder beds. The build compartment is the volume in a 3D printing apparatus where 3D objects (206) are formed by successive consolidation of thin layers of powder. The build compartment is designed with at least two vertical wall structures (203, 204) movable in relation to each other. The movable wall structures (203, 204) are at least partly overlapping in the movable direction, providing self-sealing for a variable volume for enclosing powder. Contrary to other available designs, this solution does not need a compressible sealing material, for example an elastomer, a textile felt or a braided rope, to prevent powder leakage from the build compartment. The advantages are more reliable sealing and no risk of contamination of the powder by debris from sealing material.
B29C 64/153 - Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
B33Y 30/00 - ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING - Details thereof or accessories therefor
The present invention relates to a method for manufacturing a three-dimensional object by solidifying selected areas of consecutive powder layers. At least one electron beam successively irradiates predetermined sections of each powder layer by moving an interaction region in which the electron beam interacts with the powder layer. Electromagnetic radiation from a radiation source is directed onto the powder layer to reduce local electrostatic charging in the interaction region. In this way, levitation and scattering of charged powder will be avoided.
The present invention relates to a method for removing powder from a component or part produced by metal additive manufacturing systems based on powder beds. The method comprising the steps; to manufacture a part by additive manufacturing, said part having at least one internal cavity with at least one external opening. Said internal cavity is at least partly filled with powder, said powder in said internal cavity having grains agglomerated or connected to each other; to evacuate gas from said internal cavity; to add liquid electrolyte to said internal cavity; to use an electrochemical process for separating connected powder grains in said cavity.
The present invention relates to a method for removing powder from a component or part produced by a powder bed additive manufacturing system. The method comprises the steps; providing a part, the part having at least one internal cavity with at least one external opening, the at least one cavity being at least partly filled with powder grains, the powder grains being connected to each other and to the walls of the cavity by mechanical, frictional, electrical, physical or chemical forces; adding medium in liquid phase to the at least one cavity of the part, the liquid having the property that it expands in phase transition from liquid to solid phase; transforming added medium to solid phase to loosen and break up at least a fraction of the powder grains connections from each other; and removing powder from the at least one internal cavity.
B22F 3/105 - Sintering only by using electric current, laser radiation or plasma
B22F 3/24 - After-treatment of workpieces or articles
B33Y 40/00 - Auxiliary operations or equipment, e.g. for material handling
B08B 9/00 - Cleaning hollow articles by methods or apparatus specially adapted thereto
B08B 3/12 - Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
B22F 5/10 - Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
The present invention relates to a cathode assembly for emitting charged particles, used in for example an electron gun as source for generating an electron beam. The cathode assembly has a cathode comprising an emitting member and a carrier. The emitting member is mounted in the carrier, and the carrier is electrically connected to a holder. The cathode is heated by irradiation from an external source, whereby the emitting member emits charged particles from an emitting surface at an emitting temperature. The connection between the carrier and the holder provides a thermal barrier for reducing the amount of thermal energy transferred from the cathode to the holder.
