Abstract: In an automatic cutting device for a boiler tube water wall, cost can be reduced significantly by exactly cutting position in a boiler tube water wall, and at the same time by operating four automatic cutting devices for a boiler tube water wall by one operator by making the cutting work full automatic, in order to decrease the manpower and labor cost and to significantly reduce the term of work.

Abstract: An automatic grinding apparatus includes a constant rotating grinder (24) having a motor (25) in which a load current increases or decreases due to the metal removal rate per unit hour, a travelling device for moving the grinder three-dimensionally along the grinding surface, a sliding device (20) for adjusting the distance between the grinder and an object (50, 51) to be found and a controller for controlling the sliding device to allow the load current of the grinding motor to be constant. An articulated robot or a cartesian coordinate robot is used for the travelling device. The automatic grinding apparatus starts the grinding motor at first, halting the travelling device at the initiation of grinding, permitting the grinder to approach the object to be ground after a time interval and starting the travelling device simultaneously or a little later after detecting that the grinding disk (26) contacts the object to be ground, due to the variation of the load current of the grinding motor.