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 . 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, comprising a device for setting the gas content in the liquid.  
     
     
         2 . The apparatus according to  claim 1  comprising a device for admixing gas to the liquid.  
     
     
         3 . The apparatus according to  claim 2  wherein the gas consists of air.  
     
     
         4 . The apparatus according to  claim 2 , wherein the device for admixing gas comprises a setting arrangement for setting the quantity of gas which is added.  
     
     
         5 . The apparatus according to  claim 2 , wherein the device for admixing gas to the liquid is arranged in at least one of a tank for the liquid, a pump for delivering the liquid and a delivery line for the liquid.  
     
     
         6 . The apparatus according to  claim 2 , wherein the device for admixing gas is designed with a pressure which is greater than the delivery pressure of the liquid.  
     
     
         7 . The apparatus as according to  claim 2 , wherein the device for admixing gas is designed to admix gas to the liquid in a proportion of volume of up to 70%, measured on the basis of the total volume.  
     
     
         8 . The apparatus according to  claim 6 , wherein the device for admixing gas is designed to generate a delivery pressure of less than 100 bar.  
     
     
         9 . The apparatus according to  claim 6 , wherein the device for admixing gas is designed to generate a delivery pressure of less than 50 bar.  
     
     
         10 . The apparatus according to  claim 1 , wherein an accelerating arrangement for accelerating the liquid is provided.  
     
     
         11 . The apparatus according to  claim 10 , wherein the apparatus is designed such that the liquid can be accelerated to a velocity of over 20 m/s.  
     
     
         12 . The apparatus according to  claim 10 , wherein the acceleration arrangement has at least one nozzle.  
     
     
         13 . The apparatus according to  claim 10 , wherein the accelerating arrangement includes an arrangement for setting the distance between at least one outlet opening for the liquid and the surface, and is designed such that the acceleration can be set between the at least one outlet opening and the surface as a function of the cross section of a liquid feed opening and the cross section of the gap between the surface and the at least one outlet opening.  
     
     
         14 . The apparatus according to  claim 1 , which is designed to use abrasive particles with a mean grain diameter of less than 50 (m.  
     
     
         15 . The apparatus according to  claim 14  which is designed to use abrasive particles with a mean grain diameter from 1 to 10 (m.  
     
     
         16 . The apparatus according to  claim 14 , wherein the device is designed to admix gas in order to generate gas bubbles in the liquid with a mean diameter which is larger than the mean grain diameter of the abrasive particles.  
     
     
         17 . A method for controlling the material removal-rate during removal of material from a surface of a workpiece during grinding and/or polishing of surface, the method comprising the step of adding gas in a delivery liquid for abrasive particles.  
     
     
         18 . The method according to  claim 17  wherein gas inclusions consist of air inclusions.  
     
     
         19 . A process for removing material from a surface of a workpiece using abrasive particles which are delivered by a liquid, comprising the step of setting the gas content in the liquid.  
     
     
         20 . The process according to  claim 19  wherein material is removed from the surface by grinding and/or polishing said surface.  
     
     
         21 . The process according to  claim 19 , comprising the further step of adding gas to the liquid.  
     
     
         22 . The process according to  claim 21 , wherein the gas consists of air.  
     
     
         23 . The process according to  claim 19 , wherein the liquid is supplied with gas amounting to 0 to 70% of the volume.  
     
     
         24 . The process according to  claim 20 , 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.  
     
     
         25 . The process according to  claim 20 , wherein the surface is both ground and polished with abrasive particles with a mean grain diameter of less than 50 (m.  
     
     
         26 . The process according to  claim 25 , wherein the abrasive particles have a mean grain diameter from 1 to 10 (m.  
     
     
         27 . The process according to  claim 19 , wherein the delivery pressure of the liquid is kept constant at less than 100 bar, for both grinding and polishing.  
     
     
         28 . The process according to  claim 27 , wherein the delivery pressure of the liquid is kept constant at less than 50 bar.  
     
     
         29 . The process according to  claim 19 , wherein the liquid used is predominantly water.  
     
     
         30 . The process according to  claim 19 , wherein gas bubbles which are larger than the abrasive particles are generated in the liquid.