Method for producing wall parts of a housing for pressure vessels

Abstract

The invention relates to a method for producing wall parts ( 24 ) of a housing for pressure vessels by means of a 3-D printing method, wherein material is applied layer-by-layer in order to form each wall part ( 24 ). Said method is characterized in that, in case of wall part geometries ( 28 ) that lead to distortions ( 44 ) that impede the application of material, the layer thickness in the application of material must be selected in such a way that the particular distortion ( 44 ) is avoided and that the formation of wall part geometries ( 28 ) that are critical in this respect is performed without support parts.

1 . A method for producing wall parts ( 24 ) of a housing ( 10 ) for pressure vessels by means of a 3D printing method, wherein material is applied layer-by-layer to form each wall part ( 24 ), characterized in that in the case of wall part geometries ( 28 ), which result in warping ( 44 ) which prevents the material application, the layer thickness for the material application is selected sufficiently large that the respective warping ( 44 ) is prevented and that the formation of to this extent critical wall part geometries ( 28 ) is realized free of support parts ( 40 ). 
     
     
         2 . The method according to  claim 1 , characterized in that the critical wall part geometry ( 28 ) during construction of the housing ( 10 ) is formed from a layer ( 32 ) projecting in a pointed or thin-walled manner in the direction of an inner wall ( 30 ) of same, the layer thickness of which along the material application plane ( 38 ) is selected larger than the previous layers in the construction of the housing ( 10 ) with non-critical wall part geometry. 
     
     
         3 . The method according to  claim 1 , characterized in that the respective pointed or thin-walled projecting layer ( 32 ) of the critical wall part geometry ( 28 ) with its layer ( 32 ) in the region of the projection encloses an overhang angle (a) relative to the material application plane ( 38 ) of less than 30°, preferably of less than 15°, particularly preferably of less than 5°. 
     
     
         4 . The method according to  claim 1 , characterized in that the respective warping ( 44 ) to be avoided in critical wall part geometries ( 28 ) is formed by hardened material parts, which project in the direction of the continuous, layer-by-layer material build-up on the application side ( 46 ) and which constitute a collision hazard for a material application tool ( 22 ), which is used for the respective 3D printing method. 
     
     
         5 . The method according to  claim 1 , characterized in that the wall parts ( 24 ) on the inner side ( 30 ) of the finished housing ( 10 ) form a spheroid, preferably in the form of a sphere. 
     
     
         6 . The method according to  claim 1 , characterized in that it is applied in the top third, preferably in the top sixth, in particular before closure of the spheroid. 
     
     
         7 . The method according to  claim 1 , characterized in that with the contacting of the adjacent wall parts ( 24 ) with completion of the spheroid on the inner wall side ( 30 ) of the housing ( 10 ) the layer application takes place with a layer thickness as is selected at the start of the material removal process with formation of the wall parts ( 24 ). 
     
     
         8 . The method according to  claim 1 , characterized in that but for the region of at least one potential media connection point ( 14 ) and/or at least one potentially present reinforcement part ( 18 ), which is preferably arranged in the equatorial region ( 20 ) of the spheroid on the outer wall of the housing ( 10 ), the material thickness of the housing ( 10 ) is uniformly realized by means of the material application. 
     
     
         9 . The method according to  claim 1 , characterized in that as a 3D printing method
 selective laser sintering, or   electron beam melting   
       is used, and in that the metal powder used for this is selected from the materials
 steel, 
 stainless steel, 
 aluminum, 
 titanium, 
 nickel, etc. 
 
       and mixtures thereof. 
     
     
         10 . A pressure housing, in particular envisaged for a pressure vessel in the form of a Helmholtz resonator, an air chamber or a hydraulic accumulator, produced with a method according to  claim 1 , characterized in that in a region above the equator ( 20 ), in particular in a top polar cap region ( 34 ) of a spheroid formed from the inner wall ( 30 ) of the housing ( 10 ), preferably in a spherical shape, the material roughness of the inner wall ( 30 ) before any remachining is greater than in the region below the equator ( 20 ), in particular in the direction of a bottom polar cap region ( 42 ), which is passed through by a media connection point ( 14 ). 
     
     
         11 . The pressure housing according to  claim 10 , characterized in that it is formed from one piece.