CNC machine tool is a kind of automatic machine tool equipped with program control system, which can make the machine tool move and process parts according to the programmed program. It integrates new technologies such as machinery, automation, computer, measurement, microelectronics, etc., and uses a variety of sensors. The sensors used in CNC machine tools mainly include photoelectric encoders, linear gratings, proximity switches, temperature sensors, Hall sensors, Current sensors, voltage sensors, pressure sensors, liquid level sensors, resolvers, inductosyn, speed sensors, etc, mainly used to detect position, linear displacement and angular displacement, speed, pressure, temperature, etc.

1. Requirements of CNC machine tools for sensors

1) High reliability and strong anti-interference;

2) Meet the requirements of accuracy and speed;

3) Easy to use and maintain, suitable for machine tool operating environment;

4) Low cost.

Different types of CNC machine tools have different requirements for sensors. Generally speaking, large machine tools require high speed response, and medium-sized and high-precision CNC machine tools require accuracy.

2. Application of inductosyn

The inductosyn is made by using the principle that the mutual inductance of two planar windings changes with different positions. Its function is to convert angular or linear displacement into phase or amplitude of induced electromotive force, which can be used to measure linear or angular displacement. According to its structure can be divided into linear and rotary two. The linear induction synchronizer is composed of two parts: a fixed length and a sliding rule. The fixed length is installed on the machine bed, and the sliding rule is installed on the moving part and moves with the worktable. The stator of the rotary induction synchronizer is a fixed disc, and the rotor is a rotating disc. The inductosyn has the advantages of high precision and resolution, strong anti-interference ability, long service life, simple maintenance, long-distance displacement measurement, good manufacturability, and low cost. Rotary induction synchronizer is widely used in machine tools and instruments of the turntable and a variety of rotary servo control system.