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.

Description

[0001]This application is a division of application Ser. No. 11 / 186,802, filed Jul. 22, 2005.BACKGROUND OF THE INVENTION[0002]The invention relates to the use of gas inclusions in an abrasive liquid and to a process for removing material during grinding and / or polishing of surfaces of workpieces.[0003]It is known to grind or polish surfaces using abrasive particles which are delivered in a liquid. This has the advantage that there is no need for a grinding tool.[0004]The material-removal rate from the surface depends firstly on the size of the abrasive particles in the jet. Secondly, it depends on the energy and therefore the velocity of the particles at the instant that they strike the surface. The material-removal rate is to be understood as meaning the amount of material removed per unit time.[0005]U.S. Pat. No. 5,700,181 has disclosed, for example, a process for grinding and a nozzle for accelerating the abrasive liquid. The abrasive liquid is delivered into the nozzle at a high...

AI Technical Summary

Benefits of technology

[0010]The object of the present invention is to avoid the drawbacks of the known prior art, i.e. in particular to provide an improved apparatus and an improved process for grinding and / or polishing surfaces, in which it is simple to change between grinding and polishing. In particular, the material-removal rate is to be set individually in the simplest possible way.

[0011]This object is achieved by the use of gas inclusions in the abrasive liquid and by a process for removing material during grinding and / or polishing of surfaces as described below. Surprisingly, it has been found that for the same size of abrasive grain and the same process parameters (e.g. delivery pressure), the material-removal rate rises with an increase in gas content. If the apparatus is provided with a device for setting the gas content in the liquid, therefore, it is easy to control or alter the material-removal rate. It is possible, by virtue of the present invention, to achieve high material-removal rates with relatively small grain sizes. Setting a high gas content increases the material-removal rate without larger abrasive grain having to be used.

Problems solved by technology

Secondly, it depends on the energy and therefore the velocity of the particles at the instant that they strike the surface.

These known processes have the drawback that processes which remove large amounts of material, in particular grinding, have to use coarser abrasive particles than precision-grinding and polishing processes.

Also, the transition from grinding to polishing cannot take place continuously.

If coarser particles are still present during the precision grinding or polishing, these particles lead to deep scratches, which can render the entire workpiece unusable.

This increases the procurement or production costs.

This in turn increases the working time and the production costs.

Moreover, contamination can result or the workpiece may be damaged.

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