Active shielding type capacitor height-following measuring device

Abstract

The invention relates to the technical field of numerical control machining and provides an active shielding type capacitor height-following measuring device. The stray capacitance of environment change to a cutting head and the stray capacitance of the environment to a cable are isolated. By eliminating the two main error sources and designing a remaining stray capacitance compensating circuit, the remaining stray capacitance in the cable is automatically compensated and matched, so that the measuring precision is greatly improved. According to the technical scheme, the active shielding type capacitor height-following measuring device is composed of a connector and a capacitance measuring head; a workpiece to be cut and the connector are connected through metal to be conductive as a whole which serves as one pole of a plate capacitor; the capacitance measuring head is made of metal materials, an insulation layer made of ceramic is located between the capacitance measuring head and the connector, and the capacitance measuring head serves as the other pole of the plate capacitor; and an active shielding layer, the active shielding type signal transmission cable and an active shielding driving circuit are further arranged, and the active shielding layer is closely attached to the outside of the connector in a wrapping mode. The active shielding type capacitor height-following measuring device is mainly applied to numerical control machining occasions.

Description

technical field [0001] The invention relates to the technical field of numerical control machining, in particular to a height-tracking measuring device for a processing head of a laser cutting device. Background technique [0002] During the laser cutting process, in order to obtain the maximum laser power at the incision and ensure the quality of the incision, the laser focus needs to be located at about 1 / 3 of the thickness of the workpiece surface. In the process of laser cutting and processing plates, unfavorable factors such as radian lines, flatness, and high-temperature deformation on the surface of the plate, if the distance between the cutting head and the surface of the workpiece cannot be measured in real time and the cutting height is kept at a constant value, the cutting effect will be relatively poor. It can't even reach the qualified cutting standard. [0003] Therefore, the height from the surface of the cut workpiece to the processing head must be kept at a...

AI Technical Summary

Problems solved by technology

[0005] The existing capacitance and height measurement devices are all coaxial. The disadvantage of this method is that during the processing, the stray capacitance changes in the environment where the cutting head and transmission signal cables are located will directly affect the circuit noise, resulting in measurement errors, which cannot meet high-speed High-precision measurement requirements, and high requirements on the length and quality of transmission cables, on-site debugging is required

In addition, some existing high-speed measuring devices convert tiny capacitors into digital frequency signals for transmission, which improves the anti-interference ability of the transmission signal cable, but the cutting head is still vulnerable to environmental noise.

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