Airflow pollution detection device for air inlet end of laser head

Abstract

The invention provides a laser head air inlet end airflow pollution detection device, which is placed between an air outlet end and a laser head air inlet end, and comprises a light emitting diode part, a spectroscope, a first photodiode detection part, a second photodiode detection part, a signal acquisition and analysis module and a sealing part, the air flow is output through the air outlet end, passes between the spectroscope and the second photodiode detection part and then enters the air inlet end of the laser head; a light beam emitted by the light emitting diode part passes through the spectroscope, one part of the light beam is reflected to the first photodiode detection part to form a first instantaneous reflection photoelectric signal U1, and the other part of the light beam is transmitted to the second photodiode detection part to form a first instantaneous transmission photoelectric signal U2; and the signal acquisition and analysis module receives the first instantaneous reflection electric signal U1 and the first instantaneous transmission photoelectric signal U2, and judges the airflow pollution condition of the air inlet end of the laser head according to the ratio S of the first instantaneous transmission photoelectric signal U2 to the first instantaneous reflection electric signal U1.

Description

Technical Field

[0001] The present invention relates to the field of laser processing technology, and in particular to an airflow contamination detection device at an air inlet end of a laser head. Background Art

[0002] In laser processing applications, the laser processing head, as a core component, integrates multiple disciplines such as optics, mechanics, electronics, and fluids. Fluids, as a core part of the laser processing head, are extremely important for the effect and efficiency of laser processing. For example, in laser cutting, the cutting of different materials requires cutting gas flows of different components, such as using oxygen to assist combustion to accelerate cutting; or using nitrogen protection to prevent oxidation; or using air, which is economical and convenient and can be used in processing occasions with low requirements; or using argon to cut active metals. For example, in laser welding, gas flow can prevent oxidation, reduce spatter, improve welds, increase laser utilization and reduce pores, etc. Commonly used gases include nitrogen and argon.

[0003] During the processing, the airflow cavity of the laser processing head is located at the lower end of the laser optical lens, such as the lower end of the protective lens of the fiber-optic output laser processing head and the lower end of the focusing lens of the CO2 laser processing head. When used in laser processing, the airflow is transmitted from the client's airflow storage equipment through many media such as air pipe joints and pipelines into the internal cavity of the laser processing head, and finally output from the light output end of the laser processing head to play a role. During the flow of the airflow in the internal cavity of the laser processing head, it will act on the laser optical lens that cooperates with it. However, during the long-stroke flow of the client's output airflow, various contaminants such as moisture, sealing raw tape, and grease may exist, which are finally input into the laser processing head. On the one hand, it causes partial blockage of the airflow cavity, and on the other hand, it will partially condense on the lower surface of the laser optical lens, thereby causing anisotropy and instability in laser processing and even burning the internal core of the laser head.

[0004] At present, laser processing heads, especially fiber-optic output laser processing heads, have added photoelectric sensing methods such as temperature measurement and stray light detection to determine the contamination of the protective mirror in contact with the airflow. Although the contamination of the laser optical lens can be determined by changes such as temperature rise and stray light, the alarm threshold is set. If it is lower than the alarm threshold, risk prevention cannot be carried out. In addition, there are many situations of laser optical lens contamination, such as laser processing splash ablation, surface environmental pollution, etc. Before the alarm threshold is reached, the laser optical lens mirror surface may be easily adsorbed. The moisture, grease and other pollutants that are relatively transparent to the laser beam may cause unstable processing, and the efficiency will gradually slow down or even be unable to process. On the other hand, many current detection methods such as the aforementioned detection methods are all for detecting the core components related to the optical lens. On the contrary, there is basically no direct or indirect detection of the airflow channel and cavity, and it is difficult to further increase the relevant pollution detection methods due to the complexity of the internal cavity of the laser head. Finally, when the laser processing head is burned due to airflow pollution, it is impossible to define the responsible party, which may bury hidden dangers for the performance of the product. Summary of the invention

[0005] The present invention provides an airflow pollution detection device at the air inlet end of a laser head, which is placed between the air outlet end of a customer and the air inlet end of a laser processing head, and can effectively improve the solution to the above-mentioned problem by analyzing and distinguishing the pollution situation through photoelectric sensing detection.

[0006] The specific plan is as follows.

[0007] A device for detecting airflow pollution at the air inlet end of a laser head, the device is placed between the air outlet end and the air inlet end of the laser head, and comprises: a light emitting diode part, a spectroscope, a first photodiode detection part, a second photodiode detection part, a signal acquisition and analysis module, and a sealing part; the airflow is output through the air outlet end, passes between the spectroscope and the second photodiode detection part, and then enters the air inlet end of the laser head; The light emitting diode unit includes a light emitting diode, and the light beam emitted by the light emitting diode passes through the beam splitter, and a part of the light beam is reflected by the beam splitter to the first photodiode detection unit to form a reflected light signal, and the first photodiode detection unit receives the reflected light signal and converts it into a first instantaneous reflected photoelectric signal U1, and a part of the light beam is transmitted by the beam splitter and passes through the airflow to the second photodiode detection unit to form a transmitted light signal, and the second photodiode detection unit receives the transmitted light signal and converts it into a first instantaneous transmitted photoelectric signal U2; The sealing part seals the light emitting diode part, the beam splitter, the first photodiode detection part, the second photodiode detection part and the air flow channel from the air outlet to the air inlet of the laser head; The first photodiode detection unit and the second photodiode detection unit are connected to the signal acquisition and analysis module, and the signal acquisition and analysis module is used to receive the first instantaneous reflection photoelectric signal U1 and the first instantaneous transmission photoelectric signal U2, and judge the airflow contamination condition at the air inlet end of the laser head according to the ratio S of the first instantaneous transmission photoelectric signal U2 and the first instantaneous reflection photoelectric signal U1, S=U2 / U1.

[0008] Furthermore, the pollution detection device also includes a protective window, which is arranged between the spectroscope and the second photodiode detection part. The air flow is output through the air outlet, passes between the spectroscope and the protective window, and then enters the air inlet of the laser head.

[0009] Furthermore, the light emitting diode unit includes an output mirror for converting the light beam output by the light emitting diode into a parallel light beam.

[0010] Furthermore, the beam splitter is a wedge-shaped mirror, and along the propagation direction of the light beam of the light-emitting diode, the wedge-shaped mirror includes a first plane mirror surface and a second plane mirror surface in sequence, and the angle between the two plane mirror surfaces is 5°-60°.

[0011] Furthermore, the first plane mirror is coated with a dichroic film, which partially reflects and partially transmits the light beam incident on the first plane mirror to form the reflected light signal and the transmitted light signal, and the ratio of reflectivity to transmittance is [1 / 19, 19].

[0012] Furthermore, when no airflow is initially introduced into the airflow pollution detection device, the light beam emitted by the light emitting diode passes through the spectroscope, a portion of the light beam is reflected by the spectroscope to the first photodiode detection unit to form a reflected light signal, and a portion of the light beam is transmitted by the spectroscope to the second photodiode detection unit to form a transmitted light signal. The sampling frequencies of the first photodiode detection unit and the second photodiode detection unit are the same; The first photodiode detection unit receives the reflected light signal and converts it into a second instantaneous reflected photoelectric signal U 10 The second photodiode detection unit receives the transmission light signal and converts it into a second instantaneous transmission photoelectric signal U 20 The signal acquisition and analysis module receives the second instantaneous reflected photoelectric signal U 10 , the second instantaneous transmission photoelectric signal U 20 , and calculate the second instantaneous reflected photoelectric signal U in the short time period T1 10 , the second instantaneous transmission photoelectric signal U 20 The mean value U 10avg , U 20avg , define the initial value K0=U20avg / U 10avg ; The signal acquisition and analysis module determines the airflow contamination at the air inlet end of the laser head according to the variation range of the ratio S relative to the initial value K0 and the short-term T1 fluctuation amplitude percentage Y1 and the long-term T2 fluctuation amplitude percentage Y2 of the ratio S, and the T2 time period is composed of N T1 time periods; In the short-term T1 time period, the short-term fluctuation amplitude of the ratio S is Y1. , (1) Among them U 2max is the maximum value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode detection unit during the T1 period, U 2min is the minimum value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode detection unit during the T1 period, U 2avg is the average value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode detection unit in the T1 period; The long-term fluctuation parameter of the ratio S is defined as follows: within the long-term T2 time period, the long-term fluctuation amplitude ratio of the ratio S is Y2; , (2) Among them U 2avg-max is the average value U of the N short-time first transmission photoelectric signals received by the second photodiode detection unit in the long time period T2 2avg The maximum value, U 2avg-min is the average value U of the N short-time first transmission photoelectric signals received by the second photodiode detection unit in the long time period T2 2avg The minimum value of .

[0013] Furthermore, the T1 time period is in the range of 1ms-1s, and the T2 time period is in the range of 1min-5min.

[0014] Furthermore, when the short-term fluctuation amplitude of the ratio S exceeds the range of [0, 5%] compared to Y1, the signal acquisition and analysis module determines that the gas source and the laser processing head need to be cleaned.

[0015] Furthermore, the short-term fluctuation amplitude of the ratio S does not exceed the range of [0, 5%] compared to Y1, and the long-term fluctuation amplitude does not exceed the range of [0, 5%] compared to Y2. (1) If the ratio S satisfies S≥[0.8, 1]×K0, the signal acquisition and analysis module determines that the laser processing head can work normally; (2) If the ratio S is within the range of S<[0.8, 1]×K0, the signal acquisition and analysis module determines that the gas source needs to be cleaned immediately and the laser processing head also needs to be cleaned.

[0016] Further, when the short-term fluctuation amplitude of the ratio S does not exceed the range of [0, 5%] compared to Y1, but the long-term fluctuation amplitude exceeds the range of [0, 5%] compared to Y2, and the ratio S gradually decreases; (1) If the ratio S satisfies S≥[0.8, 1]×K0, the signal acquisition and analysis module determines that the laser processing head can still work normally; (2) If the ratio S is within the range of S<[0.8, 1]×K0, the signal acquisition and analysis module determines that the contamination detection device and the laser processing head need to be cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments of the present invention are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 Optical path diagram of the airflow contamination detection device at the air inlet end of the laser head provided by the present invention; Figure 2 This is a structural diagram of the airflow contamination detection device at the air inlet end of a laser head provided by the present invention.

[0019] In the figure, 1. light emitting diode, 2. output mirror, 3. spectrometer, 4-1. first coupling mirror, 4-2. second coupling mirror, 5-1. first photodiode, 5-2. second photodiode, 6. protective window, 7. air flow channel. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0021] This embodiment discloses a device for detecting airflow pollution at the air inlet end of a laser head. Figure 1 , 2 As shown, the airflow pollution detection device is placed between the air outlet and the air inlet of the laser head, and the airflow pollution detection device includes: a light-emitting diode part, a spectroscope 3, a first photodiode detection part, a second photodiode detection part, a signal acquisition and analysis module and a sealing part; the airflow is output through the air outlet, passes through the airflow channel 7 between the spectroscope 3 and the second photodiode detection part, and then enters the air inlet of the laser head.

[0022] The light emitting diode unit includes a light emitting diode 1, the first photodiode detection unit includes a first photodiode 5-1, and the second photodiode detection unit includes a second photodiode 5-2. The first photodiode 5-1 and the second photodiode 5-2 are connected to the signal acquisition and analysis module.

[0023] In the airflow pollution detection device of this embodiment, when no airflow is initially introduced, the light emitting diode 1 is powered on to emit a light beam, part of the light beam is reflected by the spectroscope 3 to form a reflected light signal, and part of the light beam is transmitted by the spectroscope 3 to form a transmitted light signal. The sampling frequencies of the first photodiode 5-1 and the second photodiode 5-2 are the same, and the reflected light signal is received by the first photodiode 5-1 to form a second instantaneous reflected photoelectric signal U 10 The transmitted light signal is received by the second photodiode 5-2 to form a second instantaneous transmitted photoelectric signal U 20 The signal acquisition and analysis module receives the second instantaneous reflected photoelectric signal U 10 , the second instantaneous transmission photoelectric signal U 20 , and calculate the second instantaneous reflected photoelectric signal U in the short time period T1 10 , the second instantaneous transmission photoelectric signal U 20 The mean value U 10avg , U 20avg , define the initial value K0=U 20avg / U 10avg The short-time T1 period may be within a time range of 1 ms-1 s.

[0024] After the airflow is introduced, part of the light beam emitted by the light emitting diode is reflected by the beam splitter 3 to the first photodiode 5-1 to form a first instantaneous reflected photoelectric signal U1, and part of the light beam is transmitted by the beam splitter 3 to the second photodiode 5-2 to form a first instantaneous transmitted photoelectric signal U2. Since the reflected light is directly reflected by the beam splitter 3 without passing through the airflow, after the airflow is introduced, the first instantaneous reflected photoelectric signal U1=U 10 That is, the first instantaneous reflected photoelectric signal U1 after the airflow is introduced is not affected by the airflow; while part of the light beam is transmitted by the spectrometer 3 and then passes through the airflow to enter the second photodiode 5-2. If there are pollutants in the airflow, it will affect the intensity of the transmitted light received by the second photodiode 5-2, thereby affecting the first instantaneous transmitted photoelectric signal U2. The first instantaneous transmitted photoelectric signal U2 changes with the situation of pollutants in the airflow.

[0025] Therefore, the pollution detection device of this embodiment connects the signal acquisition and analysis module to the first photodiode detection unit and the second photodiode detection unit respectively. When airflow passes through, the signal acquisition and analysis module is used to receive the first instantaneous reflection photoelectric signal U1 and the first instantaneous transmission photoelectric signal U2, and defines S=U2 / U1. According to the variation range of the ratio S relative to the initial value K0 and the fluctuation amplitude percentage of the ratio S, the airflow pollution condition at the air inlet end of the laser head is judged.

[0026] The short-term fluctuation parameter of the ratio S is defined as: within the short-term T1 time period, the short-term fluctuation amplitude of the ratio S is Y1, , (1) According to the sampling frequency set by the second photodiode 5-2, U 2max is the maximum value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode 5-2 in the T1 period, U 2min is the minimum value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode 5-2 during the T1 period, U 2avg is the average value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode 5-2 in the T1 time period, wherein the T1 time period may be within the time range of 1 ms-1 s.

[0027] When the pollutant concentration in the gas source is too high, or a large pollutant passes through the pollution detection device, this part of the pollutant will seriously block the transmitted light, causing the intensity of the transmitted light passing through the spectrometer 3 to decrease significantly in an instant. Therefore, within a very short T1 time period, the ratio S changes rapidly and significantly, that is, Y1 exceeds the range of [0, 5%]. Therefore, the signal acquisition and analysis module determines that the gas source and the laser processing head need to be cleaned.

[0028] When the short-term fluctuation amplitude ratio of the ratio S does not exceed the range of ±[0, 5%] of Y1, the long-term fluctuation parameter of the ratio S is defined as follows: within the long-term T2 time period, the long-term fluctuation amplitude ratio of the ratio S is Y2, and the T2 time period consists of N T1 time periods.

[0029] , (2) Among them U 2avg-max is the average value U of the N short-time first transmission photoelectric signals received by the second photodiode 5-2 in the long time period T2 2avg The maximum value, U 2avg-min is the average value U of the N short-time first transmission photoelectric signals received by the second photodiode 5-2 in the long time period T2 2avg The minimum value of T2. The T2 time period may be within the time range of 1 min to 5 min.

[0030] (1) When the short-term fluctuation amplitude of the ratio S does not exceed the range of [0, 5%] compared with Y1, and the long-term fluctuation amplitude does not exceed the range of [0, 5%] compared with Y2, that is, the situation of excessively high air source pollution concentration and large pollutants is excluded, and the ratio S is relatively stable in the long-term T2 period, at this time, A) If the ratio S satisfies S≥[0.8, 1]×K0, the signal acquisition and analysis module determines that the laser processing head can work normally; B) If the ratio S is within the range of S<[0.8, 1]×K0, it means that the pollutant content in the gas source is relatively high. The signal acquisition and analysis module determines that the gas source needs to be cleaned immediately, and the laser processing head also needs to be cleaned.

[0031] (2) When the short-term fluctuation amplitude of the ratio S does not exceed the range of [0, 5%] compared to Y1, but the long-term fluctuation amplitude exceeds the range of [0, 5%] compared to Y2, and the ratio S gradually decreases, it means that the air source pollution concentration is too high and the large pollutants are excluded. However, the ratio S gradually decreases during the T2 time period, which means that there are pollutants that can adhere to the mirror surface at both ends of the airflow channel of the transmission light path of the pollution detection device. In this case, the adhered pollutants accumulate over time, causing the ratio S to continue to decrease.

[0032] A) If the ratio S satisfies S≥[0.8, 1]×K0, the signal acquisition and analysis module determines that the laser processing head can still work normally; B) If the ratio S is within the range of S<[0.8, 1]×K0, it means that a large amount of adhesive pollutants are adsorbed in the contamination detection device, and the signal acquisition and analysis module determines that the contamination detection device and the laser processing head need to be cleaned.

[0033] Furthermore, the airflow pollution detection device of this embodiment also includes a sealing part for sealing the light-emitting diode part, the spectroscope 3, the first photodiode detection part, and the second photodiode detection part to isolate them from the external environment and prevent airflow leakage.

[0034] Preferably, the pollution detection device of this embodiment may further include a protection window 6, which is disposed between the beam splitter 3 and the second photodiode detection unit. The airflow is output through the air outlet, passes between the beam splitter 3 and the protection window 6, and then enters the air inlet of the laser head. When there are adherent pollutants in the airflow, the protection window 6 can share the pollution with the beam splitter 3, so that the intensity change of the light incident on the second photodiode detection unit through the beam splitter 3 and the protection window 6 is more obvious, thereby improving the sensitivity of the pollution detection device.

[0035] Preferably, the light emitting diode unit comprises an output mirror 2 for converting the light beam output by the light emitting diode 1 into a parallel light beam.

[0036] Furthermore, the beam splitter 3 is a wedge-shaped mirror, and along the propagation direction of the light beam, the wedge-shaped mirror includes a first plane mirror and a second plane mirror in sequence, and the angle between the two plane mirrors is 5°-60°. A beam splitter film is coated on the first plane mirror, and the light beam incident on the first plane mirror is partially reflected and partially transmitted to form the reflected light signal and the transmitted light signal, and the reflectivity and transmittance ratio range is [1 / 19, 19].

[0037] Preferably, the first photodiode detection unit further includes a first coupling mirror 4 - 1 , and the second photodiode detection unit further includes a second coupling mirror 4 - 2 .

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser head air intake end airflow contamination detection device, characterized in that: The pollution detection device is placed between the air outlet and the air inlet of the laser head, and comprises: a light emitting diode part, a spectroscope, a first photodiode detection part, a second photodiode detection part, a signal acquisition and analysis module, and a sealing part; the air flow is output through the air outlet, passes between the spectroscope and the second photodiode detection part, and then enters the air inlet of the laser head; The light emitting diode unit includes a light emitting diode, and the light beam emitted by the light emitting diode passes through the beam splitter, and a part of the light beam is reflected by the beam splitter to the first photodiode detection unit to form a reflected light signal, and the first photodiode detection unit receives the reflected light signal and converts it into a first instantaneous reflected photoelectric signal U1, and a part of the light beam is transmitted by the beam splitter and passes through the airflow to the second photodiode detection unit to form a transmitted light signal, and the second photodiode detection unit receives the transmitted light signal and converts it into a first instantaneous transmitted photoelectric signal U2; The sealing part seals the light emitting diode part, the beam splitter, the first photodiode detection part, the second photodiode detection part and the air flow channel from the air outlet to the air inlet of the laser head; The first photodiode detection unit and the second photodiode detection unit are connected to the signal acquisition and analysis module, and the signal acquisition and analysis module is used to receive the first instantaneous reflection photoelectric signal U1 and the first instantaneous transmission photoelectric signal U2, and judge the airflow contamination condition at the air inlet end of the laser head according to the ratio S of the first instantaneous transmission photoelectric signal U2 and the first instantaneous reflection photoelectric signal U1, S=U2 / U1.

2. The laser head air inlet end airflow contamination detection device according to claim 1, characterized in that: The pollution detection device also includes a protection window, which is arranged between the spectroscope and the second photodiode detection part. The airflow is output through the air outlet, passes between the spectroscope and the protection window, and then enters the air inlet of the laser head.

3. The laser head air intake end airflow contamination detection device according to claim 1, characterized in that: The light emitting diode unit includes an output mirror for converting the light beam output by the light emitting diode into a parallel light beam.

4. The laser head air inlet end airflow contamination detection device according to claim 1, characterized in that: The beam splitter is a wedge-shaped mirror. Along the propagation direction of the light beam of the light emitting diode, the wedge-shaped mirror comprises a first plane mirror surface and a second plane mirror surface in sequence, and the angle between the two plane mirror surfaces is 5°-60°.

5. The laser head air inlet end airflow contamination detection device according to claim 4, characterized in that: The first plane mirror is coated with a beam splitting film, which partially reflects and partially transmits the light beam incident to the first plane mirror to form the reflected light signal and the transmitted light signal, and the ratio of reflectivity to transmittance is [1 / 19, 19].

6. The laser head air inlet end airflow contamination detection device according to claim 1, characterized in that: When the airflow pollution detection device is not initially supplied with airflow, the light beam emitted by the light emitting diode passes through the spectroscope, a portion of the light beam is reflected by the spectroscope to the first photodiode detection part to form a reflected light signal, and a portion of the light beam is transmitted by the spectroscope to the second photodiode detection part to form a transmitted light signal. The sampling frequencies of the first photodiode detection unit and the second photodiode detection unit are the same; The first photodiode detection unit receives the reflected light signal and converts it into a second instantaneous reflected photoelectric signal U 10 The second photodiode detection unit receives the transmission light signal and converts it into a second instantaneous transmission photoelectric signal U 20 The signal acquisition and analysis module receives the second instantaneous reflected photoelectric signal U 10 , the second instantaneous transmission photoelectric signal U 20 , and calculate the second instantaneous reflected photoelectric signal U in the short time period T1 10 , the second instantaneous transmission photoelectric signal U 20 The mean value U 10avg , U 20avg , define the initial value K0=U 20avg / U 10avg ; The signal acquisition and analysis module determines the airflow contamination at the air inlet end of the laser head according to the variation range of the ratio S relative to the initial value K0 and the short-term T1 fluctuation amplitude percentage Y1 and the long-term T2 fluctuation amplitude percentage Y2 of the ratio S, and the T2 time period is composed of N T1 time periods; In the short-term T1 time period, the short-term fluctuation amplitude of the ratio S is Y1. ，（1） Among them U 2max is the maximum value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode detection unit during the T1 period, U 2min is the minimum value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode detection unit during the T1 period, U 2avg is the average value of the first instantaneous transmission photoelectric signal U2 received by the second photodiode detection unit in the T1 period; In the long-term T2 time period, the long-term fluctuation amplitude ratio of the ratio S is Y2; ，（2） Among them U 2avg-max is the average value U of the N short-time first transmission photoelectric signals received by the second photodiode detection unit in the long time period T2 2avg The maximum value, U 2avg-min is the average value U of the N short-time first transmission photoelectric signals received by the second photodiode detection unit in the long time period T2 2avg The minimum value of .

7. The laser head air inlet end airflow contamination detection device according to claim 6, characterized in that: The short-term T1 time period is in the range of 1ms-1s, and the long-term T2 time period is in the range of 1min-5min.

8. The laser head air inlet end airflow contamination detection device according to claim 6, characterized in that: When the short-term fluctuation amplitude of the ratio S exceeds the range of [0, 5%] compared to Y1, the signal acquisition and analysis module determines that the gas source and the laser processing head need to be cleaned.

9. The laser head air inlet end airflow contamination detection device according to claim 6, characterized in that: The short-term fluctuation amplitude of the ratio S does not exceed the range of [0, 5%] compared with Y1, and the long-term fluctuation amplitude does not exceed the range of [0, 5%] compared with Y2. (1) If the ratio S satisfies S≥[0.8, 1]×K0, the signal acquisition and analysis module determines that the laser processing head can work normally; (2) If the ratio S is within the range of S<[0.8, 1]×K0, the signal acquisition and analysis module determines that the gas source and the laser processing head need to be cleaned immediately.

10. The laser head air intake end airflow contamination detection device according to claim 6, characterized in that: When the short-term fluctuation amplitude of the ratio S does not exceed the range of [0, 5%] compared with Y1, the long-term fluctuation amplitude exceeds the range of [0, 5%] compared with Y2, and the ratio S gradually decreases; (1) If the ratio S satisfies S≥[0.8, 1]×K0, the signal acquisition and analysis module determines that the laser processing head can work normally; (2) If the ratio S is within the range of S<[0.8, 1]×K0, the signal acquisition and analysis module determines that the contamination detection device and the laser processing head need to be cleaned.

Images