Method for finishing complex shapes in workpieces

Abstract

A method of forming a complex form in a workpiece includes moving a grinding tool having a complex shape relative to a surface of a workpiece to form a complex shape opening in the workpiece, and the grinding tool is tilted in a lateral plane relative to the workpiece.

What is claimed is: 
     
         1 . A method of forming a complex form in a workpiece comprising:
 moving a grinding tool having a complex shape relative to a surface of a workpiece to form a complex shape opening in the workpiece, wherein the grinding tool is tilted in a lateral plane relative to the workpiece.   
     
     
         2 . The method of  claim 1 , further comprising forming a rough slot in the workpiece prior to moving the grinding tool. 
     
     
         3 . The method of  claim 2 , wherein forming a rough slot comprises rotating a grinding wheel having a generally annular shape against a portion of the workpiece to form the rough slot. 
     
     
         4 . The method of  claim 3 , wherein the rough slot comprises a generally rectangular cross-sectional shape as viewed in a lateral plane of the workpiece. 
     
     
         5 . The method of  claim 1 , wherein a bottom surface of the workpiece is formed to have a substantially convex curvature. 
     
     
         6 . The method of  claim 5 , wherein the substantially convex curvature defines at least a portion of the bottom surface having a raised portion. 
     
     
         7 . The method of  claim 5 , wherein the substantially convex curvature defines at least a portion of a bottom surface of the complex shape opening. 
     
     
         8 . The method of  claim 1 , wherein the grinding tool comprises a grinding quill tool. 
     
     
         9 . The method of  claim 1 , wherein during moving, the grinding tool is tilted in a lateral plane relative to the workpiece. 
     
     
         10 . The method of  claim 1 , wherein the grinding tool is tilted at an angle sufficient to space a bottom surface of the grinding tool from a bottom surface of the workpiece. 
     
     
         11 . The method of  claim 1 , wherein the grinding tool is tilted at an angle relative to a normal axis of the workpiece in the lateral plane. 
     
     
         12 . The method of  claim 1 , wherein the grinding tool is tilted at an angle of not greater than about 10 degrees and at least about 0.1 degrees. 
     
     
         13 . The method of  claim 1 , wherein the grinding tool is tilted at an angle sufficient to space a bottom surface of the grinding tool from a bottom surface of a rough slot in the workpiece. 
     
     
         14 . The method of  claim 1 , wherein moving comprises removing material from at least a portion of a side surface of a rough slot of the workpiece while simultaneously limiting contact of a bottom surface of the grinding tool with a bottom surface of the rough slot. 
     
     
         15 . The method of  claim 1 , wherein moving comprises rotating the grinding tool relative to the workpiece for forming a re-entrant shape opening in the workpiece. 
     
     
         16 . The method of  claim 1 , wherein moving comprises finishing at least a portion of a surface of the workpiece defining a complex shape opening to a surface roughness (Ra) of not greater than about 2 microns. 
     
     
         17 . The method of  claim 1 , wherein the workpiece comprises a nickel-based superalloy material. 
     
     
         18 . The method of  claim 1 , wherein moving comprises rotating the grinding tool at a speed of at least about 10,000 rpm and not greater than about 250,000 rpm. 
     
     
         19 . The method of  claim 1 , wherein moving further comprises:
 contacting the grinding tool to at least a first portion of a first side surface of the workpiece on a first pass; and   contacting the grinding tool to at least a second portion of a second side surface of the workpiece on a second pass, wherein the first portion and the second portion are different portions.   
     
     
         20 . The method of  claim 1 , wherein the grinding tool comprises a body having a form depth (FD) of at least about 0.1, wherein the form depth is described by the equation [(Rl−Rs)/Rl], wherein Rs is a smallest radius (Rs) at a point along the longitudinal axis of the bonded abrasive body and Rl is a largest radius (Rl) at a point along the longitudinal axis of the bonded abrasive body.