Backup pad

Abstract

A method of tuning the contact pressure across an abrasive disc is presented. The method includes coupling the abrasive disc to a backup pad comprising a pressure tuning feature that causes an experienced pressure by a worksurface, across a radius of the abrasive disc, to be uniform. The method also includes abrading a worksurface by contacting the abrasive disc to the worksurface. The backup pad causes the abrasive disc to have a cut rate that is substantially uniform across the surface of the abrasive disc when compared to the abrasive disc on a backup pad with no pressure tuning feature.

1 . A method of managing the contact pressure across an abrasive disc, the method comprising:
 coupling the abrasive disc to a backup pad comprising a pressure tuning feature that causes an experienced pressure by a worksurface, across a radius of the abrasive disc, to be uniform;   abrading a worksurface by contacting the abrasive disc to the worksurface; and   wherein the backup pad causes the abrasive disc to have a cut rate that is substantially uniform across the surface of the abrasive disc when compared to the abrasive disc on a backup pad with no pressure tuning feature.   
     
     
         2 . The method of  claim 1 , wherein the pressure tuning feature is elastically deformable. 
     
     
         3 . The method of  claim 1 , wherein the pressure tuning feature is positioned between the backup pad and the abrasive disc. 
     
     
         4 . (canceled) 
     
     
         5 . The method of  claim 1 , wherein the pressure tuning feature is made of multiple layers or multiple materials in a layered or agglomerate construction. 
     
     
         6 . (canceled) 
     
     
         7 . (canceled) 
     
     
         8 . The method of  claim 1 , wherein the pressure tuning feature has a conical cavity mounted on a conical surface of the backup pad. 
     
     
         9 . The method of  claim 1 , wherein the hardness of the pressure tuning feature changes across the pad from its center toward its perimeter. 
     
     
         10 . A backup pad for an abrasive system, the backup pad comprising:
 a tool engaging feature;   an abrasive article engaging feature; and   a compressible feature that changes a cut rate profile of an abrasive article attached to the abrasive article engaging feature.   
     
     
         11 . (canceled) 
     
     
         12 . The backup pad of  claim 10 , wherein the compressible feature is elastically deformable. 
     
     
         13 . (canceled) 
     
     
         14 . The backup pad of  claim 10 , wherein the compressible feature comprises a material which has been patterned,  3 D printed, embossed, or engraved to provide the desired deformability. 
     
     
         15 . (canceled) 
     
     
         16 . The backup pad of  claim 10 , wherein the compressible feature is made of multiple layers and/or multiple materials in a layered or agglomerate construction. 
     
     
         17 . (canceled) 
     
     
         18 . The backup pad of  claim 10 , wherein the compressible feature includes a material having an elastic modulus of less than about 650 psi. 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . The backup pad of  claim 10 , wherein the hardness of the compressible feature changes across the pad from its center toward its perimeter. 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . The backup pad of  claim 21 , wherein the compressible feature comprises of concentric rings with different harnesses. 
     
     
         25 - 27 . (canceled) 
     
     
         28 . A spindle for a robotic abrasive system, the spindle comprising:
 a tool-engaging shaft;   a backup pad engaging surface; and   wherein the backup pad engaging surface comprises a pressure tuning feature that modifies a pressure profile exerted by the backup pad against a worksurface.   
     
     
         29 . The spindle of  claim 28 , and wherein the tool-engaging shaft engages a motive robotic arm. 
     
     
         30 . The spindle of  claim 29 , and wherein the motive robotic arm comprises a force control unit. 
     
     
         31 . The spindle of  claim 30 , and wherein a controller adjusts the force control unit based on feedback received through the spindle. 
     
     
         32 - 28 . (canceled) 
     
     
         39 . The spindle of  claim 29 , wherein the backup pad engaging surface has a perimeter with a plurality of indentations. 
     
     
         40 . The spindle of  claim 39 , wherein the pressure tuning feature is positioned between the backup pad and the abrasive disc.