Numerical Control Apparatus

A numerical control apparatus that performs machining of a workpiece according to a machining program including a machining block and variably controls speed of a servo axis and a main axis based on an override value specified through an override switch, the numerical control apparatus comprising:

• a storing unit that stores, in a storage device, machining conditions including at least a tool number, a servo-axis feed speed, and number of main-axis rotations specified in the machining program, and an override value of the servo axis and an override value of the main axis specified through the override switch in association with the machining conditions;
• a monitoring unit that monitors whether a combination of machining conditions that matches machining conditions specified in the machining block to be executed is present in the storage device;
• and
• a control unit that, when a combination of machining conditions that matches the machining conditions specified is present, controls the speed of the servo axis and the main axis with servo-axis feed speed and number of main-axis rotations specified in the machining block each multiplied by a corresponding override value stored in the storage device.

A numerical control apparatus that performs machining of a workpiece according to a machining program including a machining block and variably controls speed of a servo axis and a main axis based on an override value specified through an override switch, the numerical control apparatus comprising:

• a storing unit that stores, in a storage device, machining conditions including at least a tool number, a servo-axis feed speed, and a number of main-axis rotations specified in the machining program, and an override value of the servo axis and an override value of the main axis specified through the override switch in association with the machining conditions;
• a monitoring unit that monitors whether a combination of machining conditions that matches machining conditions specified in the machining block to be executed is present in the storage device;
• and
• a control unit that, when a combination of machining conditions that matches the machining conditions specified is present, determines whether override multiplication is permitted based on a preset signal, and controls the speed of the servo axis and the main axis with feed speed and number of main-axis rotations each multiplied by a corresponding override value and a current override value when override multiplication is permitted, and controls the speed of the servo axis and the main axis with feed speed and number of main-axis rotations each multiplied by a corresponding override value when override multiplication is not permitted.

A numerical control apparatus that performs machining of a workpiece according to a machining program and variably controls speed of a servo axis and a main axis based on an override value specified through an override switch, the numerical control apparatus comprising:

• a storing unit that stores main-axis load current during machining in a storage device;
• a comparing unit that compares currently specified main-axis load current with stored main-axis load current;
• and
• a control unit that, based on a comparison result obtained by the comparing unit, decreases an override value of the servo axis at a preset rate when the currently specified main-axis load current is larger than the stored main-axis load current, and increases the override value of the servo axis at the preset rate when the currently specified main-axis load current is smaller than the stored main-axis load current, so that the currently specified main-axis load current is coincide with the stored main-axis load current.