Internal circular grinding

Internal circular grinding is a production technique that is often used to manufacture roller bearings, see Fig. 8.33. The production costs for such components are mainly determined by the required grinding operations, whereby internal circular grinding is the greatest cost factor. This is one of the reasons why in recent years, users have applied grinding wheels with cubic crystalline boron nitride (CBN) embedded in ceramic material, especially for internal circular grinding. 

With this background, the term adaptive internal circular grinding defines a process control method, for example, in which a process parameter... 

Fig. 8.33. Principle of internal circular grinding (derived from [172])...

Internal circular grinding machines are usually equipped with high frequency grinding spindles (three-phase asynchronous motors) and frequency converters for continuously variable speed control. As a measure of the mechanical power emitted by the grinding spindle, one can use the electrical output power delivered by the converter, which can easily be acquired by conventional measurement techniques. The required control variable - one speaks in this case of constant-power grinding - is therefore almost free of charge. 

The method applied here for measuring the control value requires a fast reacting and soft mechanical structure at the place where the process force acts. Internal circular grinding fulfils this requirement automatically due to the small dimensions of the grinding wheel (i. e. small moment of inertia) and the slim grinding arbour (= elastic beam). In contrast, external plimge grinding will not necessarily fulfil this condition. 

---