As everyone knows, the laser cutting machine is composed of a variety of hardware device and a software operating system combination, reasonable collocation of hardware and software components of a complete and efficient laser cutting machine, all parts are independent of its mission, but one of the most important component is the sensor.In the laser cutting process, in order to improve the cutting quality, reduce waste, in the cutting head installed on some special sensors to ensure the cutting quality can produce stable and consistent, but also to increase security.
The displacement sensor can be divided into contact and non-contact two types, compared with contact sensor, non-contact sensor to ensure high resolution at the same time, with fast dynamic response, low lag error.
Non contact sensor, sometimes called proximity sensor (proximitysensor), is the earliest application of proximity switch, which is object detection and sensitive probe close to a certain distance, given the switch signal, because it can be used for displacement of a moving object is measured, so this kind of sensor is also called non-contact displacement sensors the commonly used displacement sensor has the magnetostrictive displacement sensor, eddy current displacement sensor, capacitive displacement sensor, displacement sensor, inductor.
According to the principle of various sensors, the capacitance sensor has high sensitivity and the advantages are as follows:
1. Has the advantages of simple structure, strong adaptability, easy to manufacture, easy to ensure high accuracy, can be made into small size sensor, in order to achieve the special measurement, can work under high temperature, strong radiation and strong magnetic field environment, can bear high pressure, high impact overload, etc..
2. Good dynamic response, due to the electrostatic attraction between the plates is very small, the energy needed is small, and the movable part can be very small and very thin, so the natural frequency of high dynamic response time is short, can work in a few megahertz frequencies, especially suitable for dynamic measurement.
3. Low fever and its low temperature coefficient, the capacitance value of the sensor to the electrode material independent, can choose a low temperature coefficient of material, the outside temperature stable, can ensure good stability.
Thus, these advantages are very suitable for laser processing, for laser cutting head, you can say that the use of capacitive displacement sensor is most appropriate.
Analysis of the basic structure of capacitive sensor
Using the displacement capacitance sensor and composite sensor is composed of laser nozzle body, inside and outside the two different metal conical shell set together, inside and outside the shell middle ceramic dielectric layer, shell Grounding Selection and inner insulation, shielding sensor, tapered tip side is connected to the lower part of an inner shell and the outer annular metal sheet cutting the insulation, the annular metal sheet metal workpiece is composed of two plates of a capacitor sensor, from the inner shell in a channel signal acquisition system connected to sensors work sequentially through this channel, in the emission layer of metal plate (sheet metal ring) charged, the probe laser processing machine is connected on the upper end. When the laser beam passes through the inner metal shell penetrates in the laser cutting process, the nozzle to the workpiece gap distance changes have great influence on the cutting quality And if the distance is too small, huge recoil pressure acts on the lens, the lens is slag particle collision or attachment, causing damage to the lens, another end of the nozzle is very vulnerable to erosion of slag, the influence of the nozzle hole roundness, destroy the symmetry of the cutting direction, supersonic flow of small spacing will work the over expansion of the nozzle gap is easy to produce shock, spacing decreases, the shock wave occurrence area to expand the gas nozzle od direction, pressure fluctuation, the pressure of the non symmetry will make the gas density change, the formation of density gradient field, the gas density variation of the coverage increases with the increase of the gas pressure. Strength also increase with pressure, while the nozzle gap is too large, will make the gas nozzle is too far away from the workpiece, pressure nozzle in the gap will be reduced, resulting in surface overheating The melting zone is enlarged and the kerf is widened.
Of course, in addition to the laser cutting machine is the core components of capacitance sensor, ensure the precision of laser cutting machine cutting effect, there are many other many core components are indispensable, such as laser is another core component.
A key component of laser cutting machine is many, here we can not explain, usually cutting for the maintenance and upkeep of the main parts of the work, not only can save costs, but also improve the cutting efficiency.
