Numerical controller for machine tool
AssigneeFanuc Corporation
InventorYuuki Morita
Life of this patent
Estimating the term…
Abstract
To provide a numerical controller for a machine tool capable of reducing heat generation and realizing stable heavy cutting, and also capable of realizing efficient light cutting. A numerical controller comprises: first speed change means which changes the feed speed of a feed axis drive motor at the start of cutting to an initial speed lower than a command speed, based on magnetic flux content at the start of cutting; and second speed change means which changes the feed speed from the initial speed to the command speed continuously or intermittently based on time elapsed from the start of cutting and a time constant for change in the magnetic flux content.
Claims18
A numerical controller which controls a machine tool with a spindle motor formed from an induction motor, and a feed axis drive motor, the numerical controller comprising:
- a processor;
- and
- a non-transitory computer-readable medium having a program stored thereon that, when executed by the processor, causes the numerical controller to:
- acquire magnetic flux content at the spindle motor;
- store a time constant for change in the magnetic flux content at the spindle motor;
- accept a command speed and issue a command instructing a feed speed to the feed axis drive motor;
- calculate time elapsed from the start of cutting;
- change the feed speed of the feed axis drive motor at the start of cutting to an initial speed lower than the command speed, based on the acquired magnetic flux content at the start of cutting;
- and
- change the feed speed from the initial speed to the command speed continuously or intermittently based on the calculated elapsed time and the stored time constant for change in the magnetic flux content.
A numerical control method for controlling a machine tool with a spindle motor formed from an induction motor, and a feed axis drive motor, the numerical control method comprising:
- acquiring, using a processor, magnetic flux content at the spindle motor;
- storing, using the processor, a time constant for change in the magnetic flux content at the spindle motor;
- accepting, using the processor, a command speed and issuing a command instructing a feed speed to the feed axis drive motor;
- calculating, using the processor, time elapsed from the start of cutting;
- issuing, using the processor, a first command for changing the feed speed of the feed axis drive motor at the start of cutting to an initial speed lower than the command speed, based on the magnetic flux content at the start of cutting acquired in said acquiring;
- and
- issuing, using the processor, a second command for changing the feed speed from the initial speed to the command speed continuously or intermittently based on the elapsed time calculated in said calculating and the time constant for change in the magnetic flux content stored in said storing.
A non-transitory computer-readable medium having a program stored thereon for causing a processor to execute a numerical control method for controlling a machine tool with a spindle motor formed from an induction motor, and a feed axis drive motor, the numerical control method comprising:
- acquiring, using the processor, magnetic flux content at the spindle motor;
- storing, using the processor, a time constant for change in the magnetic flux content at the spindle motor;
- accepting, using the processor, a command speed and issuing a command instructing a feed speed to the feed axis drive motor;
- calculating, using the processor, time elapsed from the start of cutting;
- issuing, using the processor, a first command for changing the feed speed of the feed axis drive motor at the start of cutting to an initial speed lower than the command speed, based on the magnetic flux content at the start of cutting acquired in said acquiring;
- and
- issuing, using the processor, a second command for changing the feed speed from the initial speed to the command speed continuously or intermittently based on the elapsed time calculated in said calculating and the time constant for change in the magnetic flux content stored in said storing.
Dependencies are inferred from the claim text.