Apparatus for Removing Material, Use of Gas Inclusions in an Abrasive Liquid and Process for Grinding and/or Polishing Surfaces

Abstract

The invention relates to an apparatus for removing material from a surface of a workpiece during grinding and/or polishing of the surface by means of abrasive particles which are delivered by a liquid. The apparatus comprises a device for setting the gas content in the liquid, in particular for adding gas, in particular air, to the liquid.

1 . A process for grinding or polishing a surface of a workpiece using abrasive particles which are delivered by a liquid, whereby the removal rate is controlled by setting the gas content in the liquid, wherein the surface is ground or polished with abrasive particles having a mean grain diameter of less than 50 μm. 
     
     
         2 . The process according to  claim 1 , wherein said mean grain diameter is in the range from 1 μm to 10 μm. 
     
     
         3 . The process according to  claim 1 , wherein the surface is treated with abrasive particles of the same size for each removal rate. 
     
     
         4 . The process according to  claim 1 , further comprising a step of adding gas to the liquid. 
     
     
         5 . The process according to  claim 1 , wherein the gas consists of air. 
     
     
         6 . The process according to  claim 1 , wherein the liquid is supplied with gas amounting to 0% to 70% of the total volume of the liquid and gas. 
     
     
         7 . The process according to  claim 1 , comprising a first grinding step wherein gas is admixed with the liquid for grinding the surface and a second polishing step wherein no gas is admixed with the liquid for polishing the surface. 
     
     
         8 . The process according to  claim 1 , wherein the delivery pressure of the liquid is kept constant at less than 100 bar, for both grinding and polishing. 
     
     
         9 . The process according to  claim 7 , wherein the delivery pressure of the liquid is kept constant at less than 50 bar. 
     
     
         10 . The process according to  claim 1 , wherein the liquid used is predominantly water. 
     
     
         11 . The process according to  claim 1 , wherein gas bubbles which are larger than the abrasive particles are generated in the liquid. 
     
     
         12 . A process for removing material from a surface of a workpiece during granting an polishing using abrasive particles which are delivered by a liquid, comprising the step of changing between grinding and polishing by setting the gas content in the liquid, wherein the surface is selectively ground or polished with abrasive particles of the same size. 
     
     
         13 . The process according to  claim 12 , wherein the surface is both ground and polished with abrasive particles with a mean grain diameter of less than 50 μm. 
     
     
         14 . The process according to  claim 13 , wherein the mean grain diameter is in the range of 1 μm to 10 μm. 
     
     
         15 . A process for abrasive treatment of a surface of a workpiece comprising the steps of:
 directing an abrasive fluid comprising a liquid at a constant delivery pressure and abrasive particles having a mean grain diameter less than 50 μm against said surface, and   controlling the removal rate of the abrasive fluid on the workpiece surface only by adjusting the gas content in the liquid.