Control device for working device, working device, control program for working device, control method for working device, and working method

An NC unit for a machine tool that works a workpiece by rotation of a tool, comprising:

• vibration detection means for detecting vibration which is generated by working of the workpiece;
• acquisition means for acquiring a physical quantity correlated with a phase difference between chatter vibration during previous time working and chatter vibration during this time working, on the basis of a detection result of the vibration by the vibration detection means;
• spindle speed calculation means for finding a resonance frequency of the machine tool by multiplying the physical quantity by a correction factor that changes according to the physical quantity acquired by the acquisition means, and calculating the number of rotations of the tool on the basis of the resonance frequency;
• and
• spindle speed control means for rotating the tool at a spindle speed calculated by the spindle speed calculation means.

An NC unit for a machine tool that works a workpiece by rotation of a tool, comprising:

• vibration detection means for detecting vibration which is generated by working of the workpiece;
• phase difference calculation means for calculating a phase difference of chatter vibration during working on the basis of a detection result of the vibration by the vibration detection means;
• spindle speed calculation means for bringing the number of rotations of the tool closer to the number of rotations according to a resonance frequency of the machine tool by increasing the number of rotations of the tool by a predetermined number in a case where the phase difference calculated by the phase difference calculation means is smaller than a predetermined threshold and decreasing the number of rotations of the tool by a predetermined number in a case where the phase difference is greater than the threshold;
• and
• spindle speed control means for rotating the tool at a spindle speed calculated by the spindle speed calculation means.

A control method for a machine tool that works a workpiece by rotation of a tool, comprising:

• a first process of detecting vibration which is generated by working of the workpiece;
• a second process of acquiring a physical quantity correlated with a phase difference between chatter vibration during previous time working and chatter vibration during this time working, on the basis of a detection result of the vibration;
• a third process of finding a resonance frequency of the machine tool by multiplying the physical quantity by a correction factor that changes according to the acquired physical quantity, and calculating the number of rotations of the tool on the basis of the resonance frequency;
• and
• a fourth process of rotating the tool at the calculated number of rotations.

A control method for a machine tool that works a workpiece by rotation of a tool, comprising:

• a first process of detecting vibration which is generated by working of the workpiece;
• a second process of calculating a phase difference of chatter vibration during working on the basis of a detection result of the vibration;
• a third process of bringing the number of rotations of the tool closer to the number of rotations according to a resonance frequency of the machine tool by increasing the number of rotations of the tool by a predetermined number in a case where the calculated phase difference is smaller than a predetermined threshold and decreasing the number of rotations of the tool by a predetermined number in a case where the phase difference is greater than the threshold;
• and
• a fourth process of rotating the tool at the calculated number of rotations.

A working method of working a workpiece by rotation of a tool, comprising:

• a first process of detecting vibration which is generated by working of the workpiece;
• a second process of acquiring a physical quantity correlated with a phase difference between chatter vibration during previous time working and chatter vibration during this time working, on the basis of a detection result of the vibration;
• a third process of finding a resonance frequency of a machine tool by multiplying the physical quantity by a correction factor that changes according to the acquired physical quantity, and calculating the number of rotations of the tool on the basis of the resonance frequency;
• and
• a fourth process of working the workpiece by rotating the tool at the calculated number of rotations.

A working method of working a workpiece by rotation of a tool, comprising:

• a first process of detecting vibration which is generated by working of the workpiece;
• a second process of calculating a phase difference of chatter vibration during working on the basis of a detection result of the vibration;
• a third process of bringing the number of rotations of the tool closer to the number of rotations according to a resonance frequency of the machine tool by increasing the number of rotations of the tool by a predetermined number in a case where the calculated phase difference is smaller than a predetermined threshold and decreasing the number of rotations of the tool by a predetermined number in a case where the phase difference is greater than the threshold;
• and
• a fourth process of working the workpiece by rotating the tool at the calculated number of rotations.