1. Increasing the sample speed of the current loop, combined with better current control, results in the motor heating up less.

This not only extends motor life, it also means there is less heat transfer to the ballscrew and therefore improved accuracy. Increased sampling speed can also make possible a higher velocity loop gain, helping to increase the overall performance of the machine.

2. Because many newer CNCs offer a high-speed serial connection to the servo system, the CNC can now get a lot more information about motor and drive operation through this communication link. This has resulted in improved maintenance features.

3. Serial position feedback permits higher accuracy at high feed rates. As CNCs got faster, the position feedback rate became a bottleneck in determining how fast a machine could move. Conventional feedback is carried by a signal type that limits speed according to the sample rate of the CNC and the electronics of the external encoder. Serial feedback eliminates this bottleneck, allowing fine position feedback resolution even at high speeds.
Linear motors. This technology has improved significantly in recent years in both performance and acceptance.

Every IMTS sees more machining centers offered with linear motors, and to date, Fanuc has shipped more than 1,000 units. Some of GE Fanuc’s advances have resulted in machine tool linear motors with a maximum force of 15,500 newtons and a maximum acceleration of 30 G. Other advances have led to smaller size, lighter weight and more efficient cooling. All of these changes serve to enhance the benefits linear motors offer over rotary motors—benefits that include higher acc/dec rates; superior position control and higher stiffness; improved reliability; and inherent dynamic braking.