Variable-frequency ultrasonic machining system for computer numerical control milling machine

A variable-frequency ultrasonic machining system for a computer numerical control (CNC) milling machine, comprising:

• a frame;
• a vertical spindle, rotatably provided on the frame;
• a spindle servo motor, for driving the vertical spindle;
• a worktable, provided below the vertical spindle, for clamping a workpiece and driving the workpiece to perform feed motion;
• a feed servo motor, for driving the worktable to perform the feed motion;
• a milling cutter shaft;
• and
• a milling cutter connected to the milling cutter shaft;
• wherein, the variable-frequency ultrasonic machining system further comprises:
• a connecting shaft, connected to the vertical spindle;
• a wireless transmission transmitting winding unit, fixed around the connecting shaft;
• a wireless transmission receiving winding unit, connected to the connecting shaft, and spaced apart from the wireless transmission transmitting winding unit located above;
• a cutter shaft drive motor, connected under the wireless transmission receiving winding unit and having a hollow shaft, wherein power of the cutter shaft drive motor is connected from the wireless transmission receiving winding unit and introduced through a cavity of the hollow shaft;
• a transducer, connected to the shaft of the cutter shaft drive motor, wherein power of the transducer is connected from the wireless transmission receiving winding unit and introduced through the hollow shaft of the cutter shaft drive motor;
• a horn, wherein an upper end of the horn is connected to the transducer, and a lower end thereof is connected to the milling cutter shaft;
• a cutting force detection unit, provided under the worktable, for sensing and transmitting a current cutting force;
• a temperature sensing unit, provided on one side of the milling cutter, for sensing and transmitting a current cutting temperature;
• an ultrasonic drive power supply, for providing power for the wireless transmission transmitting winding unit;
• and
• a processor, for receiving sensing signals of the cutting force detection unit and the temperature sensing unit, processing the received sensing signals according to a set program, and sending control signals to the ultrasonic drive power supply and a corresponding servo motor, respectively;
• wherein the processor comprises:
• a first programmable logic controller (PLC) module;
• a second PLC module;
• and
• a central processing unit (CPU), wherein
• an input terminal of the CPU receives a cutting force signal or a temperature signal sent from the cutting force detection unit or the temperature sensing unit, and processes the cutting force signal or the temperature signal according to a set program, to obtain a first digital control signal for controlling an output torque and speed of a corresponding servo motor and a second digital control signal for controlling an output voltage or current of the ultrasonic drive power supply;
• the first digital control signal and the second digital control signal are respectively transmitted from corresponding output terminals of the CPU to an input terminal of the first PLC module and the second PLC module;
• the first PLC module and the second PLC module respectively perform digital-to-analog (D/A) conversion on the first control digital signal and the second digital control signal to obtain a first analog control signal and a second analog control signal in correspondence;
• and
• the first analog control signal and the second analog control signal are respectively transmitted from an output terminal of the first PLC module and the second PLC module to a corresponding servo motor and the ultrasonic drive power supply.