NUMERICAL CONTROL DEVICE

• US 20150081084A1
• Filed: 06/05/2012
• Published: 03/19/2015
• Est. Priority Date: 06/05/2012
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Sato, Tomonori, Nishiwaki, Kenji, Arata, Shuichi
• Granted Patent: US 9,513,619 B2
• Time in Patent Office: Days
• US Class Current: 700/170
• CPC Class Codes: B23G 1/16 in holes of workpieces by taps B23G1/26, B23G1/32, B23G1/36 take precedence
• CPC Class Codes: G05B 19/402 characterised by control arrangements for positioning, e.g. centring a tool relative to a hole in the workpiece, additional detection means to correct position G05B19/19 takes precedence
• CPC Class Codes: G05B 19/416 characterised by control of velocity, acceleration or deceleration G05B19/19 takes precedence
• CPC Class Codes: G05B 2219/43006 Acceleration, deceleration control
• 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

Abstract

In order to enable tapping to be performed precisely and with an appropriate machining time irrespective of the diameter of a tapping tool, a configuration of the present invention includes: a program analysis unit (12) that analyzes a loaded machining program and extracts thread-related information in tapping; a gradient determination unit (14) that determines acceleration regarding movement velocity of the main spindle or the feed shaft on the basis of the thread-related information obtained by the program analysis unit (12); and an interpolation and acceleration/deceleration processing unit (13) that generates a movement command for the main spindle and the feed shaft using the acceleration determined by the gradient determination unit (14). In addition, the gradient determination unit (14) varies the acceleration during acceleration/deceleration of the main spindle or the feed shaft in accordance with the diameter of a tapping tool.

Claims

1. A numerical control device that performs tapping by synchronizing a movement of a main spindle and a movement of a feed shaft, the numerical control device comprising:

a program analysis unit that analyzes a loaded machining program and extracts thread-related information on tapping;

a gradient determination unit that determines acceleration in terms of movement velocity of the main spindle and the feed shaft on the basis of the thread-related information obtained by the program analysis unit; and

an interpolation and acceleration/deceleration processing unit that generates a movement command for the main spindle and the feed shaft using the acceleration determined by the gradient determination unit,

wherein the gradient determination unit varies the acceleration during acceleration/deceleration of the main spindle or the feed shaft in accordance with the diameter of a tapping tool.

2. The numerical control device according to claim 1, wherein

the thread-related information is any one of a tool number, a nominal designation of thread, and a pitch of thread;

and

the gradient determination unit obtains the diameter of the tapping tool on the basis of any one of the tool number, the nominal designation of thread, and the pitch of thread.

3. The numerical control device according to claim 1,

wherein the gradient determination unit obtains cutting load torque on the basis of the diameter of the tapping tool, and determines the acceleration based on the torque gained by subtracting the obtained cutting load torque from the maximum torque of a motor.

4. The numerical control device according to claim 1, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is larger than an allowable value, makes an adjustment in a direction of decreasing the acceleration calculated in the gradient determination unit.

5. The numerical control device according to claim 1, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is smaller than an allowable value, makes an adjustment in a direction of increasing the acceleration calculated in the gradient determination unit.

6. The numerical control device according to claim 2,

wherein the gradient determination unit obtains cutting load torque on the basis of the diameter of the tapping tool, and determines the acceleration based on the torque gained by subtracting the obtained cutting load torque from the maximum torque of a motor.

7. The numerical control device according to claim 2, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is larger than an allowable value, makes an adjustment in a direction of decreasing the acceleration calculated in the gradient determination unit.

8. The numerical control device according to claim 3, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is larger than an allowable value, makes an adjustment in a direction of decreasing the acceleration calculated in the gradient determination unit.

9. The numerical control device according to claim 6, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is larger than an allowable value, makes an adjustment in a direction of decreasing the acceleration calculated in the gradient determination unit.

10. The numerical control device according to claim 2, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is smaller than an allowable value, makes an adjustment in a direction of increasing the acceleration calculated in the gradient determination unit.

11. The numerical control device according to claim 3, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is smaller than an allowable value, makes an adjustment in a direction of increasing the acceleration calculated in the gradient determination unit.

12. The numerical control device according to claim 6, further comprising:

a synchronization error operation unit that calculates a synchronization error during tapping on the basis of detected positional information obtained from the main spindle drive unit and the feed shaft drive unit; and

a gradient adjustment unit that, if the synchronization error obtained in the synchronization error operation unit is smaller than an allowable value, makes an adjustment in a direction of increasing the acceleration calculated in the gradient determination unit.