Mandrels and methods for abrasive flow machining

Abstract

A method for smoothing surface roughness within a passageway is disclosed. In various embodiments, the method comprises flowing an abrasive media through the passageway and positioning a mandrel within the passageway, the mandrel being sized to create a gap between an outer surface of the mandrel and an inner surface of the passageway, wherein the abrasive media is caused to flow through the gap, abrading the inner surface of the passageway.

What is claimed is: 
     
         1 . A method for smoothing surface roughness within a passageway, comprising:
 flowing an abrasive media through the passageway; and   positioning a first mandrel within the passageway, the first mandrel being sized to create a gap between an outer surface of the first mandrel and an inner surface of the passageway,
 wherein the abrasive media is caused to flow through the gap, abrading the inner surface of the passageway. 
   
     
     
         2 . The method of  claim 1 , wherein the first mandrel is positioned at different locations within the passageway during a first smoothing operation. 
     
     
         3 . The method of  claim 2 , wherein positioning the first mandrel at different locations occurs through a passive process by action of friction between the outer surface of the first mandrel and the inner surface of the passageway. 
     
     
         4 . The method of  claim 3 , wherein the abrasive media is caused to flow in a forward direction followed by a reverse direction. 
     
     
         5 . The method of  claim 4 , wherein the first smoothing operation if followed by a second smoothing operation using a second mandrel, the second mandrel being sized larger than the first mandrel. 
     
     
         6 . The method of  claim 2 , wherein the first mandrel is connected to a cable configured to position the first mandrel at different locations. 
     
     
         7 . The method of  claim 6 , wherein the cable is connected to a cable reel configured to pay out the cable in a downstream direction. 
     
     
         8 . The method of  claim 7 , wherein the cable reel is configured to withdraw the cable in an upstream direction. 
     
     
         9 . The method of  claim 8 , wherein the passageway includes a circular cross section and the first mandrel is a first sphere. 
     
     
         10 . The method of  claim 9 , wherein a second sphere is connected to the cable adjacent the first sphere. 
     
     
         11 . The method of  claim 1 , wherein a first smoothing operation comprises traversing the first mandrel from an inlet of the passageway to an exit of the passageway followed by traversing the first mandrel from the exit of the passageway to the inlet of the passageway. 
     
     
         12 . The method of  claim 11 , wherein traversing the first mandrel from the exit of the passageway to the inlet of the passageway is caused to occur by withdrawing a cable connected to the first mandrel. 
     
     
         13 . The method of  claim 11 , wherein traversing the first mandrel from the exit of the passageway to the inlet of the passageway is caused to occur by reversing a flow direction of the abrasive media. 
     
     
         14 . The method of  claim 11 , wherein the first mandrel includes a non-spherical shape. 
     
     
         15 . An apparatus for smoothing surface roughness within a passageway, comprising:
 an abrasive flow machine configured to pump abrasive media through a component having the passageway; and   a mandrel configured for variable positioning along a length within the passageway, the mandrel being sized to create a gap between an outer surface of the mandrel and an inner surface of the passageway.   
     
     
         16 . The apparatus of  claim 15 , wherein the mandrel is sized to enable friction between the outer surface of the mandrel and the inner surface of the passageway to control the variable positioning. 
     
     
         17 . The apparatus of  claim 16 , further comprising a cable reel and a cable connected to the mandrel and wherein the cable reel is configured to control the variable positioning. 
     
     
         18 . The apparatus of  claim 17 , wherein the passageway includes a circular cross section and the mandrel is a sphere. 
     
     
         19 . A method for smoothing surface roughness within a passageway, comprising:
 positioning a mandrel within the passageway, the mandrel being sized to create a gap between an outer surface of the mandrel and an inner surface of the passageway;   flowing an abrasive media through the passageway in a first direction; and   moving the mandrel in the first direction,
 wherein the abrasive media is caused to flow through the gap, abrading the inner surface of the passageway upstream of the mandrel. 
   
     
     
         20 . The method of  claim 19 , wherein the passageway and the mandrel have a non-circular cross section and wherein the positioning of the mandrel is controlled by a rod connected to a downstream portion of the mandrel.