Why do laser cutting machines need sensors?


XT Laser-laser cutting machine

In the cutting process of laser cutting machine, the distance between the cutting head and the workpiece and the perpendicularity between the nozzle and the workpiece surface are two extremely important factors. It directly affects the processing quality. Therefore, in order to improve the cutting quality and reduce the generation of waste products, it is necessary to install some special sensors on the cutting head to ensure that it can produce stable and consistent cutting quality and increase process safety.

When the shape of the laser cutting head changes and there are uneven obstacles on the surface, the sensor will automatically detect the change and automatically adjust the height according to the change, so that the distance between the laser cutting head and the surface of the workpiece is always consistent, so that the material can be processed more quickly without continuous supervision. The displacement sensors used at home and abroad are basically capacitive, their structure and shape are compatible with the processing head, and equipped with detection signal processing unit.

Displacement measurement is the most basic measurement work. According to whether the sensor is in contact with the measured workpiece, the displacement sensor can be divided into two types: contact type and non-contact type. Compared with contact sensor, non-contact sensor can ensure high resolution. At the same time, it has the characteristics of fast dynamic response, small hysteresis error and even zero.

Non-contact sensor, sometimes called proximity sensor, is the earliest application of proximity switch, that is, when the measured object is close to a certain distance from the sensitive probe, a switch signal is given. At present, the proximity sensor has been developed to not only detect the presence of an object, but also give the distance between the object and the sensitive probe, and provide information about the shape and spatial position of the workpiece.

Because it can be used to measure the displacement of moving objects, this kind of sensor is also called non-contact displacement sensor. Common displacement sensors include hysteresis displacement sensor, eddy current displacement sensor, capacitive displacement sensor and inductive displacement sensor. Sensors, etc.

The capacitive sensor has high sensitivity and the following characteristics:

1: Good dynamic response. Because the electrostatic attraction between plates is very small, the energy required is very small, and the movable part can be made into a very small and thin shape, so its natural frequency is high and the dynamic response time is short. MHz, especially suitable for dynamic measurement.

2: Simple structure, strong adaptability, easy to manufacture, easy to ensure high accuracy, can be made into small size sensors to achieve special measurement, can work in harsh environments such as high and low temperature, strong radiation and strong magnetic field, and can withstand high pressure, high impact, overload, etc.

3: Low heat value and low temperature coefficient. Since the capacitance value of the capacitive sensor is independent of the electrode material, the material with lower temperature coefficient can be selected to ensure good stability when the external temperature is stable.

4: The relatively large change is only limited by the linear region, and its value can reach more than 100%, ensuring the resolution and measurement range of the sensor.

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