Cutting head for monitoring relative distance between cutting head and cut material in real time during laser cutting

Abstract

A cutting head used for monitoring the relative distance between the cutting head and a cut material in real time during laser cutting comprises a cutting head shell, a cutting head nozzle fixedly arranged below the cutting head shell, and a focus lens fixedly arranged in the cutting head shell and coaxially arranged with the cutting head nozzle. A laser ranging sensor is arranged on one side of the cutting head shell, a 45-degree light splitting protection lens is further arranged in the cutting head shell, and a laser cutting light beam used for cutting penetrates through the 45-degree light splitting protection lens and then coincides with a light beam, totally reflected by the 45-degree light splitting protection lens, of a laser ranging light beam used for ranging. Different from the conventional capacitance principle that a voltage difference is formed by utilizing the relative distance between a nozzle and a cut material, a light beam of a micro high-precision laser range finder is coaxial with a laser beam of the micro high-precision laser range finder by utilizing an optical structure, and the working height of a cutting head is measured in the coaxial state, so that the working height is monitored in real time, fed back immediately and adjusted at any time; and the cutting working height is dynamically reflected with high precision, it is guaranteed that laser cutting is always at the optimal cutting height, and high-quality consistency of cutting quality is achieved.

Description

Technical Field

[0001] This application relates to the field of laser cutting. Specifically, it relates to a cutting head that is used for laser cutting and instantaneously monitors the relative distance between the cutting head and the material to be cut. Background Art

[0002] Laser cutting uses a highly focused high-power density laser beam to irradiate a workpiece, causing the irradiated material to quickly melt, vaporize, ablate, or reach the ignition point. At the same time, a high-speed air flow coaxial with the beam is used to blow away the molten material, thereby achieving the separation of the workpiece. Obviously, laser cutting is a non-rigid contact processing method. According to the optical characteristics of focusing, the energy at the position of the laser beam focus is the most concentrated and the spot effect is the best. However, this focal length is a fixed value, which requires that during laser cutting, the position of the cutting head relative to the position of the material to be cut needs to maintain an absolute value. However, the outer contour and cutting characteristics of the material to be cut cannot always be in an ideal state. For example, a flat material will be affected by a flatness tolerance, a curved material needs to adjust the height of the cutting head up and down in real time following the change of curvature, there is an influence of the runout tolerance during the rotation of a pipe, and there is a real-time correction of the relative position between the cutting surface and the cutting head during the rotation of a special-shaped pipe (elliptical pipe, deformed pipe, waist-shaped pipe, etc.). Generally, during laser cutting, since the focusing component is installed in the inner cavity of the cutting head and there is a sealed high-speed air flow cavity below, the focused beam forms a focus at a position slightly below the end hole of the high-speed air flow nozzle by a few tenths of a millimeter through a protective mirror. Then, the ideal cutting height can be determined by controlling the distance between the end of the high-speed air flow nozzle of the cutting head and the material to be cut.

[0003] As Figure 1 shown, in the past, a cutting head with a height adjustment component formed a closed-loop circuit of a capacitance sensor with the material to be cut through the nozzle, a metal body. The distance fluctuation between the nozzle end face and the material would generate a corresponding voltage change. At this time, the capacitance sensor transmitted a digital signal to the device to adjust the height of the cutting head to achieve the optimal laser cutting height. However, the structure of the nozzle is generally a cone, and the end is a small-diameter plane with a small hole through which the laser focus spot passes and the air flow ejects. Because this is not a perfect cone and there is a circular boundary, when measuring the height with the material, it is not the ideal point on the axis that acts, but a circular surface or one side of the boundary. This results in an error in the measured height from the axis height and cannot achieve a very high-precision height measurement feedback. Summary of the Utility Model

[0004] The main purpose of this application is to provide a cutting head that can instantaneously monitor the relative distance between the cutting head and the material to be cut during laser cutting. Different from the capacitance principle that uses the relative distance between the nozzle and the material to be cut to form a voltage difference in the past, an optical structure is used to make the beam of the micro high-precision laser rangefinder coaxial with the laser beam, and the working height of the cutting head is measured in this coaxial state, so that it can be monitored at all times, instantaneously feedback, adjusted at any time, and the cutting working height can be dynamically and accurately reflected, ensuring that the laser cutting is always at the best cutting height and achieving high-quality consistency of the cutting quality.

[0005] To achieve the above object, in a first aspect, this application provides a cutting head that can instantaneously monitor the relative distance between the cutting head and the material to be cut during laser cutting, including a cutting head housing, a cutting head nozzle fixedly arranged below the cutting head housing, and a focusing lens fixedly arranged in the cutting head housing and coaxially arranged with the cutting head nozzle. A laser ranging sensor is arranged on one side of the cutting head housing, and a 45° beam splitter protection mirror is also arranged in the cutting head housing. The laser cutting beam for cutting coincides with the beam of the laser ranging beam for ranging that is totally reflected by the 45° beam splitter protection mirror after passing through the 45° beam splitter protection mirror.

[0006] Further improved, an antireflection film is arranged on one side of the 45° beam splitter protection mirror, and a reflection film is arranged on the other side of the 45° beam splitter protection mirror.

[0007] Further improved, a high-pressure gas input pipe is fixed on the cutting head nozzle, and the high-pressure gas input pipe is communicated with the inner cavity of the cutting head nozzle.

[0008] Further improved, the wavelength of the laser cutting beam is 1084nm.

[0009] Further improved, the wavelength of the laser ranging beam is 700nm.

[0010] Further improved, the laser ranging sensor is connected to the control system of the laser cutting machine.

[0011] A cutting head provided by the utility model for instantaneously monitoring the relative distance between the cutting head and the material to be cut during laser cutting. Compared with the prior art, its beneficial effects are as follows: The laser is converged into a high-energy laser cutting beam bundle through a focusing lens. The light beam passes through the 45° beam splitter protective mirror and then through the cavity of high-pressure gas, and acts on the material to be cut through the nozzle below. The ranging laser emitted by the laser ranging sensor is totally reflected by the 45° beam splitter and acts on the surface of the material to be cut through the nozzle. By installing and calibrating the relative positions of the focusing lens and the laser ranging sensor according to the rectangular coordinates, the axes of the cutting laser and the ranging laser in the space below the beam splitter can be made to coincide. Then, during cutting, the ranging laser is reflected by the surface of the material to be cut and then reaches the laser ranging sensor. Thus, the laser ranging sensor instantaneously feeds back the height signal, enabling the control system to instantaneously adjust the cutting working height according to the signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings forming a part of this application are used to provide a further understanding of this application, making other features, objects, and advantages of this application more obvious. The schematic embodiments and their descriptions of this application are used to explain this application and do not constitute an improper limitation of this application. In the drawings:

[0013] Figure 1 is a schematic diagram of the prior art;

[0014] Figure 2 is a schematic diagram of the utility model.

[0015] Among them: 1. Cutting head housing; 2. Cutting head nozzle; 3. Focusing lens; 4. 45° beam splitter protective mirror; 5. Laser ranging sensor; 6. High-pressure gas input pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] In order to enable those skilled in the art of this technology to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of this application.

[0017] It should be noted that in the description and claims of this application and the above-mentioned drawings, terms such as "first" and "second" are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of this application described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0018] In this application, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated device, element or component must have a specific orientation or be constructed and operated in a specific orientation.

[0019] Moreover, in addition to being able to represent an orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0020] In addition, the meaning of the term "plurality" should be two or more.

[0021] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will describe this application in detail with reference to the drawings and in combination with the embodiments.

[0022] As Figure 2 shown, a cutting head for instantaneously monitoring the relative distance between the cutting head and the material to be cut during laser cutting includes a cutting head housing 1, a cutting head nozzle 2 fixedly arranged below the cutting head housing 1, and a focusing lens 3 fixedly arranged in the cutting head housing 1 and coaxially arranged with the cutting head nozzle 2. A laser distance sensor 5 is arranged on one side of the cutting head housing 1. A 45° beam splitting protection mirror 4 is also arranged in the cutting head housing 1. The laser cutting beam for cutting coincides with the beam that is totally reflected by the 45° beam splitting protection mirror 4 after passing through the 45° beam splitting protection mirror 4 for the laser ranging beam.

[0023] The laser distance sensor 5 is connected to the control system of the laser cutting machine. Thus, the laser distance sensor 5 can constantly detect the surface height of the cutting material, and the control system of the cutting machine can dynamically adjust the working height of the cutting head with high precision, so that the laser cutting always maintains the optimal cutting height and ensures the cutting quality.

[0024] Among them, the 45° beam splitting protective mirror 4 is different from the conventional ordinary plane mirror protective mirror. An antireflection film is provided on one side of the 45° beam splitting protective mirror 4, and a reflection film is provided on the other side of the 45° beam splitting protective mirror 4. The laser cutting beam for cutting can pass through the beam splitting protective mirror 4 without changing the optical path and energy through the antireflection film, while the reflection film totally reflects the laser measurement beam for measurement. Specifically, the wavelength of the laser cutting beam is 1084 nm, and the wavelength of the laser ranging beam is 700 nm. The antireflection film and the reflection film are selected correspondingly according to the different wavelengths of the above-mentioned cutting beam and ranging beam.

[0025] Preferably in this embodiment, a high-pressure gas input pipe 6 is fixed on the cutting head nozzle 2, and the high-pressure gas input pipe 6 is communicated with the inner cavity of the cutting head nozzle 2.

[0026] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cutting head used for real-time monitoring of the relative distance between the cutting head and the material being cut during laser cutting, characterized in that: It includes a cutting head shell, a cutting head nozzle fixedly arranged below the cutting head shell, and a focusing mirror fixedly arranged in the cutting head shell and coaxially arranged with the cutting head nozzle. A laser ranging sensor is arranged on one side of the cutting head shell, and a 45° splitting protective mirror is also arranged in the cutting head shell. After the laser cutting beam used for cutting passes through the 45° splitting protective mirror, it coincides with the laser ranging beam used for ranging that is totally reflected by the 45° splitting protective mirror.

2. A cutting head for real-time monitoring of the relative distance between the cutting head and the material being cut during laser cutting as claimed in claim 1, characterized in that: An anti-reflection film is arranged on one side of the 45° beam splitting protective mirror, and a reflective film is arranged on the other side of the 45° beam splitting protective mirror.

3. A cutting head for real-time monitoring of the relative distance between the cutting head and the material being cut during laser cutting as claimed in claim 1, characterized in that: A high-pressure gas input pipe is fixed on the cutting head nozzle, and the high-pressure gas input pipe is communicated with the inner cavity of the cutting head nozzle.

4. A cutting head for real-time monitoring of the relative distance between the cutting head and the material being cut during laser cutting as claimed in claim 1, characterized in that: The wavelength of the laser cutting beam is 1084 nm.

5. A cutting head for real-time monitoring of the relative distance between the cutting head and the material being cut during laser cutting as claimed in claim 1, characterized in that: The wavelength of the laser ranging light beam is 700nm.

6. A cutting head for real-time monitoring of the relative distance between the cutting head and the material being cut during laser cutting as claimed in claim 1, characterized in that: The laser distance measuring sensor is connected to the control system of the laser cutting machine.

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