| 摘要 |
PURPOSE:To accurately polish a workpiece while always keeping a relative position between the workpiece and a whetstone unchanged by starting a dressing device when the temperature or axial displacement of a whetstone shaft detected during a warming up period becomes larger than a set value. CONSTITUTION:A comparing circuit 40 of a dressing control device 35 compares a temperature difference DELTATt between the present temperature Tt of a whetstone shaft 13 coming from a temperature sensor 36 and reference temperature To, with a set value DELTAT set in a setting instrument 37, and when the detected value DELTATt becomes larger that the set value DELTAT and the whetstone 5 is not in machining process, a correction control circuit 41 issues a whetstone correction signal, and the dressing device 7 begins a prescribed correcting process, allowing the shape of the whetstone 5 to be corrected. Temperature T1 at the end of the correcting process is sent to a memory circuit 42, and stored as new reference temperature instead of the reference temperature To. With the elapse of a warming up period, the dressing device 7 is started at an ordinary start interval to permit the correcting process to be executed, thus enabling a distance between a work and the whetstone to be kept constant. |
