Method and system for manufacturing of three dimensional objects

Abstract

Method and system for manufacturing of three dimensional objects comprising of base substrate ( 18 ) placed on the supporting plate ( 30 ), electron beam gun ( 2 ), feed means ( 17 ) for feeding of feedstock material to melting zone, positioning system ( 31, 36 ) for positioning of said supporting plate ( 30 ) with base substrate ( 18 ), vacuum tight operating chamber ( 29 ), wherein an energy source for generating of molten pool on the substrate and for melting of feedstock material in said system is gas-discharge electron beam gun ( 2 ) with cold circular cathode ( 8 ) placed between two circular anodic electrodes placed coaxially to said cathode ( 8 ) which generates electron beam ( 9 ) in the shape of hollow inverted cone, and feedstock guide ( 17 ) is placed along the axis of said of said electron beam gun ( 2 ), and said gas-discharge electron beam gun ( 2 ) and said feedstock guide ( 17 ) are combined in one functional assembly.

What is claimed is: 
     
         1 . A system for manufacturing three-dimensional objects, said system comprising:
 a substrate placed on a supporting plate;   an electron beam gun configured to generate an electron beam having a shape of a hollow inverted cone to form a molten pool on said substrate;   a feedstock feeder configured to feed feedstock material through a feedstock guide and into a melting zone for layered manufacturing of the three-dimensional objects;   a positioning system configured to move said melting zone relative to said substrate for forming the three-dimensional objects;   a vacuum-tight operating chamber enclosing said substrate, said supporting plate, said electron beam gun, said feedstock guide, and said positioning system;   a vacuum system configured to provide an operating vacuum in the vacuum-tight operating chamber;   a control system configured to control and monitor operating conditions of said electron beam gun, said feedstock feeder, said positioning system, and said vacuum system for manufacturing the three-dimensional objects, wherein said electron beam gun is a gas-discharge electron beam gun with a circular cold cathode disposed annularly about an axis and between two circular anodic electrodes, with the circular anodic electrodes each extending coaxially to said circular cold cathode;   wherein said feedstock guide extends along the axis of said electron beam gun, and   wherein said gas-discharge electron beam gun and said feedstock guide are combined in one functional assembly.   
     
     
         2 . The system of  claim 1 , wherein said functional assembly comprising said gas-discharge electron beam gun and said feedstock guide further comprises:
 a base flange defining a hole in the center thereof, with the feedstock guide fixed coaxially within said hole in said base flange;   a circular high voltage insulator attached to said circular cold cathode and fixed to said base flange from below, with said circular high voltage insulator and said circular cold cathode each disposed coaxially with said feedstock guide;   wherein said two circular anodic electrodes includes an internal circular anodic electrode, with said internal circular anodic electrode fixed within said hole in said base flange and adjacent and coaxially to said feedstock guide; and   wherein said two circular anodic electrodes includes an external circular anodic electrode, a body of said gas-discharge electron beam gun functioning as said external circular anodic electrode.   
     
     
         3 . The system of  claim 1 , wherein said circular cold cathode defines an emission surface having a shape of a segment of a sphere with its center on the axis of said electron beam gun; and
 wherein the center of the sphere determines a position of an apex of the hollow conical electron beam generated by said electron beam gun.   
     
     
         4 . The system of  claim 1 , wherein said circular cold cathode is made of one of the following materials: aluminum, aluminum alloy, or stainless steel. 
     
     
         5 . The system of  claim 1 , further comprising:
 a circular insert with a shape of a segment of a sphere, said circular insert inserted in an emission surface of said circular cold cathode, and   wherein said circular insert is made of one of the following materials: aluminum, aluminum alloy, or hexaboride of lanthanum.   
     
     
         6 . The system of  claim 1 , wherein said circular cold cathode defines a cavity configured for circulation of water for cooling. 
     
     
         7 . The system of  claim 1 , wherein said circular cold cathode is attached to a high voltage insulator through a circular cold cathode holder, and wherein said circular cold cathode holder is made of a material that is stronger than the material of the circular cold cathode. 
     
     
         8 . The system of  claim 1 , wherein said circular cold cathode holder defines a cavity configured for circulation of cooling water. 
     
     
         9 . The system of  claim 1 , wherein cylindrical surface of said circular cold cathode is surrounded by a cylindrical by-cathode electrode. 
     
     
         10 . The system of  claim 1 , wherein said circular cold cathode is attached to a high voltage insulator having ring shape with extended free surfaces. 
     
     
         11 . The system of  claim 1 , wherein said electron beam gun further comprises:
 a base flange; and   a body including top cylindrical part attached to said base flange, said body also including a bottom conical part having an inverted conoid shape.   
     
     
         12 . The system of  claim 1 , wherein said feedstock guide defines a passage configured for circulation of cooling water. 
     
     
         13 . The system of  claim 1 , wherein said electron beam gun is regulated to operate with an operating accelerating voltage of 5-45 kV. 
     
     
         14 . The system of  claim 13 , wherein said electron beam gun is regulated to operate with an operating accelerating voltage of 5-15 kV. 
     
     
         15 . The system of  claim 1 , further comprising a power supply configured to provide a regulated power of up to 45 kW to said electron beam gun, and wherein the power of the electron beam is regulated within a range of 0-45 kW. 
     
     
         16 . The system of  claim 15 , wherein the power of the electron beam is regulated within a range of 0-15 kW. 
     
     
         17 . The system of  claim 1 , wherein said vacuum system provides operating vacuum in said operating chamber within a range of 10-10 −2  Pa while manufacturing three-dimensional objects. 
     
     
         18 . The system of  claim 1 , wherein said gas-discharge electron beam gun is configured to use an operating gas selected from one of the following gases: hydrogen, oxygen, a mixture of hydrogen and oxygen, nitrogen, helium, argon, air, or methane. 
     
     
         19 . The system of  claim 1 , wherein control of electron beam power is fulfilled by control of electron beam current which is regulated by means of change of operating gas pressure inside the gas-discharge electron beam gun. 
     
     
         20 . The system of  claim 1 , wherein said system is configured to use the feedstock material in the form of wire, cored wire, rod, wire bundle, powder, or a mixture of powders; and
 wherein said system is configured to use the feedstock material selected from the following materials: titanium, titanium alloys, intermetallic compounds of titanium, niobium, niobium alloys, intermetallic compounds of niobium, tantalum, tantalum alloys, aluminum, aluminum alloys, intermetallic compounds of aluminum, nickel based alloys, cobalt based alloys, tool steels, or a composite matrix.   
     
     
         21 . The system of  claim 1 , wherein said feedstock guide is one of a plurality of different feedstock guides for feeding different kinds of feedstock materials; and
 wherein said plurality of different feedstock guides are changeable inside a same structure of said functional assembly comprising said gas-discharge electron beam gun and said feedstock guide.   
     
     
         22 . The system of  claim 1 , wherein said functional assembly including said gas-discharge electron beam gun and said feedstock guide is rigidly fixed inside said operating chamber; and
 wherein said positioning system is configured to move said supporting plate and said substrate, thereby moving said melting zone relative to said substrate.   
     
     
         23 . The system of  claim 1 , wherein said functional assembly comprising said gas-discharge electron beam gun and said feedstock guide further comprises a base flange defining a hole, with the feedstock guide extending through said hole in said base flange;
 wherein the base flange is rigidly fixed to a top plate of said operating chamber with parts of said gas-discharge electron beam gun disposed below said base flange and inside of said operating chamber; and   wherein the feedstock material is fed into said operating chamber through said feedstock guide with one or more sealing inserts.   
     
     
         24 . The system of  claim 23  wherein said functional assembly is fixed rigidly on the top plate of said operating chamber through an intermediate spacer placed on an internal side of the top plate of said operating chamber. 
     
     
         25 . The system of  claim 1 , wherein said positioning system is configured to move said functional assembly within said operating chamber, thereby moving said melting zone relative to said substrate.