Distance-measurement focusing method applied for laser cutting processing

Abstract

The invention discloses a ranging and focusing method for laser cutting processing, and the key point is that the side of a cutting laser head is provided with a parallel light generator, a concave lens and a camera which are synchronously driven. The concave lens amplifies the light spot of the parallel light generator and projects the light spot on the surface of a work piece, the camera collect the light spot image, and then the cutting processing is carried out along with the cutting laser beam; the light spot is always projected in the front of the moving direction of the work piece, thelight spot image changes along with the fluctuant change of the work piece surface, the camera samples the light spot image in real time, and the sampled light spot image and a standard light spot image are compared by a data processor, thus obtaining the deformation amount of the surface waiting to be cut of the work piece; and according to the deformation amount, the data processor sends out control signals, drives and regulates a focus lifting device, and changes the distance between the cutting laser head and the work piece, thus keeping accurate focusing with the work piece. The method has the advantages of high focusing accuracy, agile response and strong adaptability to the surface of the processed work piece, low and practical cost, high cutting efficiency, and the like.

Description

technical field [0001] The invention relates to the technology of distance measurement, focus and focus adjustment in the field of non-contact cutting and processing, especially the distance measurement and focus method for assisting laser cutter processing. Background technique [0002] At present, laser cutting equipment has been widely used in the cutting and processing of plates. Since the concentrated energy laser is used for cutting and processing, the requirements for the accuracy of the distance between the cutting laser beam and the workpiece to be processed are relatively high. In some high-demand processing and cutting processes, in order to ensure the cutting effect and quality, it is necessary to use the corresponding auxiliary system to dynamically adjust the focus of the cutting laser beam. Among the focusing methods used in conventional laser cutting, there are mainly mechanical, inductive, capacitive, and laser point reflection methods. These focusing meth...

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Problems solved by technology

And these focusing methods all have defects of various degrees.

Among them, the mechanical type needs to use mechanical components to directly contact the processed workpiece. On the one hand, it is easy to cause scratches or damage on the surface of the processed workpiece. On the other hand, the mechanical wear of the focusing system will affect the focusing accuracy, poor durability and accuracy; inductance The processing object of the type and the capacitive type can only be limited to metal materials, and its anti-interference ability is poor, it is very easy to be affected by the electromagnetic interference of the external environment, the accuracy of the induction is not high, and the work reliability is poor; Reflective type, it uses the ranging laser emitted from the side to form a point reflection on the surface of the workpiece, and uses the time difference of reflection to measure the distance, so the accuracy is high, but the device depends on imports, and its price is expensive, especially the entire focusing device It is bulky and cannot be installed close to the cutting point of the cutting laser beam, resulting in a large span between the distance measuring point and the cutting point, with large errors, and the distance measurement method can only be carried out point by point. Once the reflection point just falls on the debris on the surface of the workpiece The laser is inaccurate, and if the reflection point just falls on the slit or hole on the surface of the workpiece, the laser will not reflect and cannot measure the distance, and the adaptability of the technology is poor.

In the actual laser cutting production process, the workpiece or material to be processed is not an absolute horizontal plane, and there is inevitably a certain amount of bending, deformation, and warping. How to adjust it accurately and timely according to the surface conditions of the workpiece or material to be processed The focal length of the cutting laser beam, the traditional technology has not yet perfect solution

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