Application analysis of laser cutting head sensor

When the shape of the workpiece changes and the surface of the laser cutting head uneven obstacles, the sensor automatically detects the change and automatically adjusts the height according to the change, so that it is always consistent with the distance of the workpiece surface.

   Displacement measurement is one of the most basic work, whether to contact with the workpiece to be measured in accordance with the sensor, displacement sensor can be divided into two types, contact and non-contact, compare with non-contact sensor and non-contact sensor in the guarantee of high resolution at the same time, with fast dynamic response and low hysteresis error, even to zero.

   Non-contact sensor, sometimes called close to the sensor, the application of the first close to switch, the tested object and sensitive probe close to a certain distance, the switching signal is given, the current close to the sensor have been developed to not only can detect the presence of object, and can give the object distance sensitive probe, and can provide information about the workpiece shape and space position, because it can be used to measure the displacement of moving object, so this kind of sensor is also known as non-contact displacement sensor, displacement sensor is commonly used with hysteresis expansion displacement sensors, electric eddy current displacement sensor, capacitive displacement sensor,Inductor displacement sensor, etc.
 

Features:

1, simple structure, strong adaptability, easy to manufacture, easy to ensure high precision, can be made into small size sensor, to achieve special measurement, can work in high and low temperature, strong radiation and strong magnetic field and other harsh environment, can withstand high pressure, high impact, overload, etc..

2, good dynamic response, due to the electrostatic force between plates is small, the required action energy is very small, and its movable part can be done very small and thin, so its natural frequency is very high, dynamic response time is short, can work at a frequency of several megahertz, especially suitable for dynamic measurement.

3. The large relative variation is only limited by the linear region, and its value can reach 100% or greater, which can guarantee the resolution and measurement range of the sensor.

4. Low heat and low temperature coefficient. Since the capacitance value of the capacitance sensor is independent of the electrode material, the material with low temperature coefficient can be selected to ensure good stability under the condition of stable external temperature.
 

Capacitance sensor:

   Laser with capacitive displacement sensor and the nozzle body composition, sensor consists of two different metal conical shells together inside and outside, inside the outer shell in the middle of ceramic dielectric, shell and inner insulation layer select earthing, shielding effect at the time of the sensor work, tapered tip on one side of the lower part of the inner layer connects a ring of metal cutting and outer insulation, the ring of metal on metal artifacts that constitute a two plates capacitance sensor, from the inner shell of a channel in the signal acquisition system connect the sensor to work through this channel, in turn in the metal layer can make launch pad (annular sheet metal) charged,The probe upper in laser processing machine, laser beam through the inner metal casing wear while working out in the process of laser cutting, the nozzle to the workpiece distance gap change has a great influence on the cutting quality, if the distance is too small, big recoil pressure will effect on the lens, the lens is slag particles slam or attached lens damage, in addition the nozzle end very vulnerable to slag erosion, influence of nozzle hole roundness, destroy the cutting direction of symmetry, and the work space is too small will lead to the expansion of the airflow in a supersonic flow, nozzle gaps prone to shock, spacing variable hours,Shock wave area to expand in the direction of nozzle diameter, gas pressure fluctuation, pressure of non symmetry change will make the gas density, formation density gradient, gas density change increases with the area of the covered with higher gas pressure, the strength also increases with increasing pressure, and the nozzle gap is too big, can make the gas nozzle are too far away from artifacts, nozzle pressure will diminish in the clearance, lead to overheating, workpiece surface melting area increase, widen the kerf width.