Process control method and apparatus

A method comprising:

• machining a workpiece using an ultrasonic vibration tool to engage abrasive particles in a slurry;
• capturing a power output from the ultrasonic vibration tool, wherein the power output is related to a vibration amplitude of a tool tip of the ultrasonic vibration tool;
• receiving the captured power output at a controller connected to an ultrasonic power supply that supplies power to the ultrasonic vibration tool;
• determining the captured power output has reached a specified level;
• and
• modifying power to the ultrasonic vibration tool by a control signal from the controller to the ultrasonic power supply.

A method comprising:

• repetitively determining a magnitude of a power output signal used to power an ultrasonic vibration tool used in an ultrasonic impact grinding machine to generate a corresponding data signal;
• repetitively determining an x-y-z position of the ultrasonic vibration tool during a grinding operation to generate a corresponding position signal;
• and
• adaptively processing the corresponding data signal and the corresponding position signal to generate a control signal for controlling an operation of a drive feed system for the ultrasonic vibration tool.