Machine tool with tapping function

• US 5,538,369 A
• Filed: 02/15/1995
• Issued: 07/23/1996
• Est. Priority Date: 02/17/1994
• Status: Expired due to Fees

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Okuda, Shinji
• Primary Examiner(s): Howell, Daniel W.
• Application Number:
  US08/389,160
• Time in Patent Office: 524 Days
• Field of Search: 408/3, 408/10, 408/129, 470/96, 364/474.02, 364/474.12, 364/474.22
• US Class Current: 408/3
• CPC Class Codes: B23G 1/18 Machines with one working spindle
• CPC Class Codes: G05B 19/186 Generation of screw- or gearlike surfaces
• CPC Class Codes: G05B 2219/45216 Tapping
• CPC Class Codes: G05B 2219/50225 Synchronize feed and spindle speed as function of pitch of screw, thread
• CPC Class Codes: Y10T 408/08 with means to regulate operation by use of templet, tape, card, or other replaceable information supply
• CPC Class Codes: Y10T 408/17 to control infeed

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.

Claims

1. 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.

2. 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.