Abstract In a machine tool equipped with a numerical control unit for digitally controlling a spindle motor, the number of revolutions and feed speed of a spindle for rigid tapping are obtained by designating the number of revolutions and the tapping pitch from an input device and calculating the feed speed of the spindle by an arithmetic device based on the designated number of revolutions and tapping pitch. Alternatively, they are obtained by designating the tapping pitch from the input device, changing the number of revolutions by a number-of-revolutions changing device and calculating the feed speed of the spindle by the arithmetic device based on the designated pitch and the changed number of revolutions. The numerical control unit controls the number of rotations of the spindle motor based on the obtained number of revolutions and also controls the axial feed of the spindle based on the obtained feed speed, thus synchronizing the number of revolutions of the tap with the feed speed of the tap with respect to the work during the tapping operation.
A machine tool equipped with a numerical control unit for digitally controlling a motor for a spindle, comprising: (a) input means for designating a revolving speed and a tapping pitch for the spindle; (b) arithmetic means for calculating a feed speed of the spindle based on said designated revolving speed and tapping pitch; and (c) said numerical control unit being operable to perform a tapping operation by controlling the rotating speed of the motor based on said designated revolving speed and also by controlling the axial movement of the spindle based on said designated tapping pitch.
Claim 2
Dependent Claim
96 words
A machine tool equipped with a numerical control unit for digitally controlling a motor for a spindle, comprising: (a) input means for designating a revolving speed and a tapping pitch for the spindle; (b) arithmetic means for calculating a feed speed of the spindle based on said designated revolving speed and tapping pitch; and (c) said numerical control unit being operable to perform a tapping operation by controlling the rotating speed of the motor based on said designated revolving speed and also by controlling the axial movement of the spindle based on said designated tapping pitch.
Claim 3
Dependent Claim
107 words
A machine tool equipped with a numerical control unit for digitally controlling a motor for a spindle, comprising: (a) input means for designating a tapping pitch for the spindle; (b) revolving speed changing means for changing a revolving speed for the spindle; (c) arithmetic means for calculating a feed speed of the spindle based on said designated tapping pitch and said changed revolving speed; and (d) said numerical control unit being operable to perform a tapping operation by controlling the rotating speed of the motor based on said changed revolving speed and also by controlling the axial movement of the spindle based on said calculated feed speed.
Claim 4
Dependent Claim
107 words
A machine tool equipped with a numerical control unit for digitally controlling a motor for a spindle, comprising: (a) input means for designating a tapping pitch for the spindle; (b) revolving speed changing means for changing a revolving speed for the spindle; (c) arithmetic means for calculating a feed speed of the spindle based on said designated tapping pitch and said changed revolving speed; and (d) said numerical control unit being operable to perform a tapping operation by controlling the rotating speed of the motor based on said changed revolving speed and also by controlling the axial movement of the spindle based on said calculated feed speed.