Arrangements and methods for abrasive flow machining

Abstract

A method of treating an interior surface of a workpiece ( 5 ); said method comprising providing a workpiece ( 5 ) having an interior passage ( 11 ) defined at least partly by said interior surface to be treated, said passage ( 11 ) having an inlet section and an outlet section; providing in said interior passage ( 11 ) at least one deflecting object ( 6 ), said deflecting object ( 6 ) having an outer surface, whereby a space is formed between said outer surface of said at least one deflecting object ( 6 ) and said interior surface of said workpiece ( 5 ); providing an abrasive fluid ( 3 ) in said space, such that said space is substantially filled with said abrasive fluid ( 3 ); and effecting flow of said abrasive medium ( 3 ) through said interior passage ( 11 ) from said inlet portion to said outlet portion.

1 . Method of treating an interior surface of a workpiece; said method comprising
 providing a workpiece having an interior passage defined at least partly by said interior surface to be treated, said passage having an inlet section and an outlet section;   providing in said interior passage at least one deflecting object, said deflecting object having an outer surface, whereby a space is formed between said outer surface of said at least one deflecting object and said interior surface of said workpiece;   providing an abrasive fluid in said space, such that said space is substantially filled with said abrasive fluid; and   effecting flow of said abrasive medium through said interior passage from said inlet portion to said outlet portion,   wherein said at least one deflecting object is moved in said passage, and said movement comprises movement in a direction parallel to a longitudinal axis of said passage.   
     
     
         2 . Method of  claim 1 , wherein said step of effecting flow comprises moving a piston in a cylinder connected to said inlet portion of said interior passage. 
     
     
         3 . Method of  claim 1 , wherein said at least one deflecting object is mounted on a rod. 
     
     
         4 . Method of  claim 3 , wherein said step of effecting flow comprises moving a piston in a cylinder connected to said inlet portion of said interior passage, and wherein said rod is connected to said piston. 
     
     
         5 . Method of  claim 3 , wherein said step of effecting flow comprises moving a piston in a cylinder connected to said inlet portion of said interior passage, and wherein said rod is movable relative to said piston. 
     
     
         6 . Method of  claim 1 , wherein said at least one deflecting object comprises multiple deflecting objects. 
     
     
         7 . Method of  claim 6 , wherein said multiple deflecting objects are connected, so as to assume a fixed distance to each other. 
     
     
         8 . Method of  claim 7 , wherein said step of effecting flow comprises moving a piston in a cylinder connected to said inlet portion of said interior passage, and wherein said multiple deflecting objects are mounted at a fixed distance to said piston. 
     
     
         9 . Method of  claim 1 , wherein said interior passage has at least one circular cross-sectional area in a plane normal to a longitudinal axis of said passage. 
     
     
         10 . Method of  claim 9 , wherein said at least one deflecting object is rotationally symmetric. 
     
     
         11 . Method of  claim 1 , wherein said interior passage has at least one square cross section in a plane normal to a longitudinal axis of said passage. 
     
     
         12 . Method of  claim 11 , wherein said at least one deflecting object has at least one square cross section. 
     
     
         13 . Method of  claim 1 , wherein said at least one deflecting object is formed by a substantially flat structure oriented, when mounted in said interior passage, normal to a longitudinal axis of said interior passage. 
     
     
         14 . Method of  claim 13 , wherein said substantially flat structure is disc-shaped. 
     
     
         15 . Method of  claim 13 , wherein said substantially flat structure is a rectangular plate. 
     
     
         16 . Method of  claim 13 , wherein said at least one deflecting object comprises multiple substantially flat structures oriented normal to a longitudinal axis of said passage. 
     
     
         17 . Method of  claim 16 , wherein all said multiple flat structures are disc-shaped. 
     
     
         18 . Method of  claim 1 , wherein an outer contour of said at least one deflecting object follows an inner contour of said interior passage. 
     
     
         19 . Method of  claim 1 , wherein said abrasive fluid comprises a shear thickening fluid. 
     
     
         20 . Method of  claim 1 , wherein said abrasive fluid further comprises abrasive particles selected from the group consisting of: boron carbide, aluminum oxide, calcite, emery (corundum), diamond dust, synthetic diamond dust, novaculite, pumice dust, sand, boron nitride, ceramic particles, ceramic iron oxide, glass powder, steel particles, silicon carbide, and zirconia alumina. 
     
     
         21 . Method of  claim 1 , wherein said movement includes reciprocal movement parallel to a longitudinal axis of said passage. 
     
     
         22 . Method of  claim 1 , wherein said movement comprises rotational movement about an axis parallel to a longitudinal axis of said passage. 
     
     
         23 . Method of  claim 1 , wherein there is provided a net flow of abrasive fluid through said passage from said inlet section to said outlet section. 
     
     
         24 . Method of  claim 1 , wherein said interior surface to be treated is a metal surface. 
     
     
         25 . Arrangement for treating an interior surface of a workpiece, said workpiece having an interior passage, said interior passage being at least partially defined by said interior surface to be treated, said interior passage having an inlet portion and an outlet portion; the arrangement comprising:
 (i) a first chamber for holding an abrasive fluid;   (ii) connecting means for connecting said workpiece to said arrangement in such a manner that a fluid-tight connection is established between said first chamber and said inlet portion of said interior passage;   (iii) pressure imposing means for imposing an elevated pressure on said abrasive fluid in said first chamber, if such is present in said first chamber; and   (iv) at least one deflecting object mountable in said interior passage, when said workpiece is connected to said arrangement, said deflecting object adapted for deflecting abrasive fluid, when such abrasive fluid is flowing through said interior passage,   wherein said deflecting object is mountable in said interior passage such as to allow movement of said deflecting object in said passage parallel to a longitudinal axis of said passage.   
     
     
         26 . Arrangement of  claim 25 , wherein said movement of said deflecting object is reciprocal movement parallel to a longitudinal axis of said passage. 
     
     
         27 . Arrangement of  claim 25 , further comprising said workpiece. 
     
     
         28 . The arrangement  claim 25 , wherein said means for imposing a pressure on said abrasive fluid in said first chamber comprises a first cylinder portion and a first piston movably arranged in said first cylinder portion. 
     
     
         29 . The arrangement of  claim 28 , wherein said at least one deflecting object is mounted on a rod. 
     
     
         30 . The arrangement of  claim 25 , said arrangement further comprising a second chamber connectable to said workpiece in a manner that a fluid tight connection is established to said outlet portion of said interior passage, said second chamber also comprising means for imposing a pressure on an abrasive fluid when such is present in said second chamber. 
     
     
         31 . The arrangement of  claim 30 , wherein said means for imposing a pressure on an abrasive fluid in said second chamber comprises a second cylinder portion and a second piston arranged in said second cylinder portion. 
     
     
         32 . The arrangement of  claim 31 , wherein said first and second pistons are movable in a manner so as to effect reciprocal movement of an abrasive fluid in said interior passage, and past said at least one deflecting object, when such abrasive fluid is present in said first and second chambers and in said interior passage. 
     
     
         33 . The arrangement of  claim 25 , wherein said interior passage has at least one circular cross-sectional area in a plane normal to a longitudinal axis of said passage. 
     
     
         34 . The arrangement of  claim 33 , wherein said at least one deflecting object is rotationally symmetric. 
     
     
         35 . The arrangement of  claim 25 , wherein said interior passage has at least one square cross-sectional area in a plane normal to a longitudinal axis of said interior passage. 
     
     
         36 . The arrangement of  claim 35 , wherein said at least one deflecting object has at least one square cross-sectional area. 
     
     
         37 . The arrangement of  claim 25 , wherein said at least one deflecting object comprises a substantially flat structure oriented normal to a longitudinal axis of said interior passage. 
     
     
         38 . The arrangement of  claim 37 , wherein said substantially flat structure is disc-shaped. 
     
     
         39 . The arrangement of  claim 37 , wherein said substantially flat structure is a rectangular plate. 
     
     
         40 . The arrangement of  claim 37 , wherein said at least one deflecting object comprises multiple substantially flat structures oriented normal to a longitudinal axis of said interior passage. 
     
     
         41 . The arrangement of  40 , wherein all said multiple flat structures are disc-shaped. 
     
     
         42 . The arrangement of  claim 25 , wherein an outer contour of said at least one deflecting object follows an inner contour of said interior passage.