A device for detecting air flow pollution at the air inlet end of a laser head

Abstract

The present invention provides an air flow pollution detection device for the air inlet end of a laser head, which is placed between the air outlet end and the air inlet end of the laser head, and includes: a light-emitting diode part, a beam splitter, 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 from the air outlet end, passes between the beam splitter and the second photodiode detection part, and then enters the air inlet end of the laser head; the light beam emitted by the light-emitting diode part passes through the beam splitter, a part of which is reflected to the first photodiode detection part to form a first instantaneous reflected photoelectric signal U1, and a part of which is transmitted to the second photodiode detection part to form a first instantaneous transmitted photoelectric signal U2; the signal acquisition and analysis module receives the first instantaneous reflected photoelectric signal U1 and the first instantaneous transmitted photoelectric signal U2, and judges the air flow pollution situation at the air inlet end of the laser head according to the ratio S of the first instantaneous transmitted photoelectric signal U2 to the first instantaneous reflected photoelectric signal U1.

Description

Technical Field

[0001] The present invention relates to the technical field of laser processing, and in particular, to an air flow pollution detection device for the 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 fluidics. And the fluid, as a major core part of the laser processing head, is extremely important for the laser processing effect and efficiency. For example, in laser cutting, different cutting airflows are required for cutting different materials. For example, oxygen is used for combustion assistance to accelerate cutting; nitrogen is used for protection to prevent oxidation; air is used, which is economical and convenient and can be applied to processing occasions with low requirements; argon is used to cut reactive metals, etc. For example, in laser welding, the air flow can prevent oxidation, reduce spatter, improve the weld seam, increase the laser utilization rate, and reduce pores. Commonly used ones include nitrogen, argon, etc.

[0003] During the processing, the air flow cavity part 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 a fiber optic output type laser processing head or the lower end of the focusing lens of a CO2 laser processing head. When in laser processing applications, the air flow is transmitted into the internal cavity of the laser processing head through various media such as a gas pipe joint and a pipeline from a client air flow storage device, etc., and finally outputs from the light output end of the laser processing head to play a role. During the flow of the air flow in the internal cavity of the laser processing head, it acts on the laser optical lens that cooperates with it. However, during the long-distance flow of the air flow output from the client, there may be various pollution components such as moisture, sealing raw tape, and lubricating grease, which are finally input into the laser processing head. On the one hand, it causes blockage of the air flow cavity part, and on the other hand, it partially condenses on the lower surface of the laser optical lens, thereby causing laser processing anisotropy, instability, and even burning out the internal core of the laser head.

[0004] At present, in a laser processing head, especially in a fiber output type laser processing head, optoelectronic sensing methods such as temperature measurement and stray light detection are added inside to determine the contamination condition of a protective mirror in contact with an air flow. Although the contamination condition of a laser optical lens can be determined through changes such as temperature rise and stray light, due to the setting of an alarm threshold, risk prevention cannot be carried out when the threshold is not reached. Moreover, there are various situations of contamination of the laser optical lens itself, such as laser processing spatter ablation and surface environmental pollution. Before the alarm threshold is far reached, the mirror surface of the laser optical lens may cause unstable processing, gradually slower efficiency or even inability to process due to contaminants relatively transparent to the laser beam, such as adsorbable moisture and grease. On the other hand, many current detections, such as the detection methods mentioned above, are all for detecting core components related to the optical lens, but there is basically no direct or indirect detection of the air flow channel and cavity, etc. Due to the complexity of the internal cavity of the laser head, it is also very difficult to further add relevant contamination detection means. Finally, when the laser processing head is damaged due to air flow contamination, it is impossible to define the responsible party, which may pose a hidden danger to the performance of the product. Summary of the Invention

[0005] The present invention provides an air flow contamination detection device for 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 the laser processing head, and analyzes and discriminates the contamination condition through optoelectronic sensing detection, so as to effectively improve the solution of the above problems.

[0006] The specific solution is as follows.

[0007] An air flow contamination detection device for the air inlet end of a laser head, the contamination detection device is placed between the air outlet end and the air inlet end of the laser head, and the contamination detection device includes: a light emitting diode part, a beam splitter, 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 from the air outlet end, passes between the beam splitter and the second photodiode detection part, and then enters the air inlet end of the laser head;

[0008] The light emitting diode part includes a light emitting diode, the light beam emitted by the light emitting diode passes through the beam splitter, a part of the light beam is reflected by the beam splitter to the first photodiode detection part to form a reflected light signal, the first photodiode detection part receives the reflected light signal and converts it into a first instantaneous reflected photoelectric signal U1, a part of the light beam is transmitted by the beam splitter and passes through the air flow to the second photodiode detection part to form a transmitted light signal, and the second photodiode detection part receives the transmitted light signal and converts it into a first instantaneous transmitted photoelectric signal U2;

[0009] 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 end to the air inlet end of the laser head;

[0010] The first photodiode detection unit and the second photodiode detection unit are connected to the signal acquisition and analysis module. The signal acquisition and analysis module is configured to receive the first instantaneous reflected optical signal U1 and the first instantaneous transmitted optical signal U2, and determine the air flow pollution condition at the air inlet end of the laser head according to the ratio S of the first instantaneous transmitted optical signal U2 to the first instantaneous reflected optical signal U1, where S = U2 / U1.

[0011] Further, the pollution detection device further includes a protective window, which is disposed between the beam splitter and the second photodiode detection unit. The air flow is output through the air outlet end, passes between the beam splitter and the protective window, and then enters the air inlet end of the laser head.

[0012] Further, 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.

[0013] Further, the beam splitter is a wedge mirror. Along the propagation direction of the light beam of the light emitting diode, the wedge mirror sequentially includes a first plane mirror surface and a second plane mirror surface, and the included angle between the two plane mirror surfaces is 5° - 60°.

[0014] Further, the first plane mirror surface is coated with a beam splitting film, which partially reflects and partially transmits the light beam incident on the first plane mirror surface to form the reflected light signal and the transmitted light signal, and the ratio of the reflectivity to the transmittance is [1 / 19, 19].

[0015] Further, when no air flow is introduced initially in the air flow pollution detection device, the light beam emitted by the light emitting diode passes through the beam splitter. 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 a part of the light beam is transmitted by the beam splitter to the second photodiode detection unit to form a transmitted light signal.

[0016] The sampling frequencies of the first photodiode detection unit and the second photodiode detection unit are the same;

[0017] The first photodiode detection unit receives the reflected light signal and converts it into a second instantaneous reflected optical signal U 10 , the second photodiode detection unit receives the transmitted light signal and converts it into a second instantaneous transmitted optical signal U 20 , and the signal acquisition and analysis module receives the second instantaneous reflected optical signal U 10 , the second instantaneous transmitted optical signal U 20 , and calculates the second instantaneous reflected optical signal U 10 , the second instantaneous transmitted optical signal U 20The mean value U 10avg 、U 20avg Define the initial value K0 = U 20avg / U 10avg ;

[0018] The signal acquisition and analysis module determines the air flow pollution condition at the air inlet end of the laser head according to the change 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. The T2 time period consists of N T1 time periods;

[0019] Within the short-term T1 time period range, the short-term fluctuation amplitude ratio of the ratio S is Y1,

[0020] , (1)

[0021] where U 2max is the maximum value of the first instantaneous transmitted photoelectric signal U2 received by the second photodiode detection unit within the T1 time period, U 2min is the minimum value of the first instantaneous transmitted photoelectric signal U2 received by the second photodiode detection unit within the T1 time period, U 2avg is the average value of the first instantaneous transmitted photoelectric signal U2 received by the second photodiode detection unit within the T1 time period;

[0022] Define the long-term fluctuation parameter of the ratio S as: within the long-term T2 time period range, the long-term fluctuation amplitude ratio of the ratio S is Y2;

[0023] , (2)

[0024] where U 2avg-max is the maximum value of the means U 2avg of the N short-term first transmitted photoelectric signals received by the second photodiode detection unit within the long-term T2 time period, U 2avg-min is the minimum value of the means U 2avg of the N short-term first transmitted photoelectric signals received by the second photodiode detection unit within the long-term T2 time period.

[0025] Furthermore, the T1 time period is in the range of 1 ms - 1 s, and the T2 time period is in the range of 1 min - 5 min.

[0026] Furthermore, when the short-term fluctuation amplitude ratio Y1 of the ratio S exceeds the range of [0, 5%], the signal acquisition and analysis module determines that the air source and the laser processing head need to be cleaned.

[0027] Furthermore, the short-term fluctuation amplitude ratio Y1 of the ratio S does not exceed the range of [0, 5%], and the long-term fluctuation amplitude ratio Y2 does not exceed the range of [0, 5%],

[0028] (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;

[0029] (2) If the ratio S is in 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.

[0030] Furthermore, when the short-term fluctuation amplitude ratio Y1 of the ratio S does not exceed the range of [0, 5%], but the long-term fluctuation amplitude ratio Y2 exceeds the range of [0, 5%], and the ratio S gradually decreases;

[0031] (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;

[0032] (2) If the ratio S is in the range of S < [0.8, 1] × K0, the signal acquisition and analysis module determines that the pollution detection device and the laser processing head need to be cleaned. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments of the present invention. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0034] Figure 1 It is the optical path diagram of the air flow pollution detection device at the air inlet end of the laser head provided by the present invention;

[0035] Figure 2 It is the structural diagram of the air flow pollution detection device at the air inlet end of the laser head provided by the present invention.

[0036] In the figure, 1. Light-emitting diode, 2. Output mirror, 3. Beam splitter, 4-1. First coupling mirror, 4-2. Second coupling mirror, 5-1. First photodiode, 5-2. Second photodiode, 6. Protection window, 7. Air flow channel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The following will describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention.

[0038] This embodiment discloses an air flow pollution detection device at the air inlet end of a laser head, such as Figure 1 、 2As shown, the air flow pollution detection device is placed between the air outlet end and the air inlet end of the laser head. The air flow pollution detection device includes: a light emitting diode part, a beam splitter 3, 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 from the air outlet end, passes through the air flow channel 7 between the beam splitter 3 and the second photodiode detection part, and then enters the air inlet end of the laser head.

[0039] The light emitting diode part includes a light emitting diode 1. The first photodiode detection part includes a first photodiode 5-1, and the second photodiode detection part 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.

[0040] In the case where no air flow is initially introduced in the air flow pollution detection device of this embodiment, the light emitting diode 1 is powered on to emit a light beam. Part of the light beam is reflected by the beam splitter 3 to form a reflected light signal, and part of the light beam is transmitted by the beam splitter 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. The reflected light signal is received by the first photodiode 5-1 to form a second instantaneous reflected photoelectric signal U 10 , and 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 transmitted photoelectric signal U 20 , and calculates the means U 10 , U 20 of the second instantaneous reflected photoelectric signal U 10avg , the second instantaneous transmitted photoelectric signal U 20avg within a short time period T1, and defines the initial value K0 = U 20avg / U 10avg . Among them, the short time period T1 can be within the time range of 1 ms - 1 s.

[0041] After the air flow is introduced, the first instantaneous reflected photoelectric signal formed by part of the light beam emitted by the light emitting diode being reflected by the beam splitter 3 to the first photodiode 5-1 is U1, and the first instantaneous transmitted photoelectric signal formed by part of the light beam being transmitted by the beam splitter 3 to the second photodiode 5-2 is U2. Since the reflected light is directly reflected by the beam splitter 3 without passing through the air flow, after the air flow is introduced, the first instantaneous reflected photoelectric signal U1 = U 10, that is, the first instantaneous reflected optoelectronic signal U1 after the air flow is introduced is not affected by the introduced air flow; while a part of the light beam is transmitted by the beam splitter 3, then passes through the air flow and enters the second photodiode 5-2. If there are pollutants in the air flow, it will affect the transmitted light intensity received by the second photodiode 5-2, and thus affect the first instantaneous transmitted optoelectronic signal U2. The first instantaneous transmitted optoelectronic signal U2 changes with the situation of pollutants in the air flow.

[0042] Therefore, the pollution detection device in this embodiment connects the signal acquisition and analysis module to the first photodiode detection unit and the second photodiode detection unit respectively. When the air flow passes through, the signal acquisition and analysis module is used to receive the first instantaneous reflected optoelectronic signal U1 and the first instantaneous transmitted optoelectronic signal U2, define S = U2 / U1, and judge the pollution situation of the air flow at the air inlet end of the laser head according to the change range of the ratio S relative to the initial value K0 and the percentage of the fluctuation amplitude of the ratio S.

[0043] Define the short-time fluctuation parameter of the ratio S as: within the short-time T1 time period range, the short-time fluctuation amplitude ratio of the ratio S is Y1.

[0044] , (1)

[0045] According to the sampling frequency set by the second photodiode 5-2, where U 2max is the maximum value of the first instantaneous transmitted optoelectronic signal U2 received by the second photodiode 5-2 within the T1 time period, U 2min is the minimum value of the first instantaneous transmitted optoelectronic signal U2 received by the second photodiode 5-2 within the T1 time period, U 2avg is the average value of the first instantaneous transmitted optoelectronic signal U2 received by the second photodiode 5-2 within the T1 time period. Among them, the T1 time period can be within the range of 1 ms - 1 s.

[0046] When the pollutant concentration in the air source is too high, or when a large pollutant passes through the pollution detection device, this part of the pollutant seriously blocks the transmitted light, resulting in a significant instantaneous reduction in the transmitted light intensity passing through the beam splitter 3. Therefore, within a very short T1 time period, the ratio S rapidly undergoes a significant jump, that is, Y1 exceeds the range of [0, 5%]. Therefore, the signal acquisition and analysis module determines that the air source and the laser processing head need to be cleaned.

[0047] When the short-time fluctuation amplitude ratio Y1 of the ratio S does not exceed the range of ±[0, 5%], define the long-time fluctuation parameter of the ratio S as: within the long-time T2 time period range, the long-time fluctuation amplitude ratio of the ratio S is Y2, and the T2 time period is composed of N T1 time periods.

[0048] , (2)

[0049] 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.

[0050] (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,

[0051] 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;

[0052] 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.

[0053] (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.

[0054] 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;

[0055] 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.

[0056] 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.

[0057] Preferably, the pollution detection device of this embodiment may further include a protection window 6. The protection window 6 is disposed between the beam splitter 3 and the second photodiode detection unit. The air flow is output from the air outlet end, passes between the beam splitter 3 and the protection window 6, and then enters the air inlet end of the laser head. When there are adherent pollutants in the air flow, the protection window 6 and the beam splitter 3 can share the pollution together, making the change in the light intensity incident on the second photodiode detection unit through the beam splitter 3 and the protection window 6 more obvious, thereby improving the sensitivity of the pollution detection device.

[0058] Preferably, the light emitting diode unit includes an output mirror 2 for changing the light beam output by the light emitting diode 1 into a parallel light beam.

[0059] Further, the beam splitter 3 is a wedge mirror. Along the light beam propagation direction, the wedge mirror sequentially includes a first plane mirror surface and a second plane mirror surface, and the included angle between the two plane mirror surfaces is 5° - 60°. A beam splitting film is plated on the first plane mirror surface to perform partial reflection and partial transmission on the light beam incident on the first plane mirror surface, forming the reflected light signal and the transmitted light signal. The ratio range of the reflectivity to the transmittance is [1 / 19, 19].

[0060] 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.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An air flow pollution detection device for the air inlet end of a laser head, characterized in that The pollution detection device is placed between the air outlet end and the air inlet end of the laser head. The pollution detection device includes: a light-emitting diode part, a beam splitter, 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 from the air outlet end, passes between the beam splitter and the second photodiode detection part, and then enters the air inlet end of the laser head. The light-emitting diode part includes a light-emitting diode. The light beam emitted by the light-emitting diode passes through the beam splitter. A part of the light beam is reflected by the beam splitter to the first photodiode detection part to form a reflected light signal. The first photodiode detection part receives the reflected light signal and converts it into a first instantaneous reflected photoelectric signal U1. A part of the light beam is transmitted by the beam splitter and passes through the air flow to the second photodiode detection part to form a transmitted light signal. The second photodiode detection part 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 end to the air inlet end of the laser head. The first photodiode detection part and the second photodiode detection part are connected to the signal acquisition and analysis module. The signal acquisition and analysis module is used to receive the first instantaneous reflected photoelectric signal U1 and the first instantaneous transmitted photoelectric signal U2, and judge the air flow pollution situation at the air inlet end of the laser head according to the ratio S of the first instantaneous transmitted photoelectric signal U2 to the first instantaneous reflected photoelectric signal U1, S = U2 / U1. When there is no air flow initially in the air flow pollution detection device, the light beam emitted by the light-emitting diode passes through the beam splitter. A part of the light beam is reflected by the beam splitter to the first photodiode detection part to form a reflected light signal, and a part of the light beam is transmitted by the beam splitter to the second photodiode detection part to form a transmitted light signal. The sampling frequencies of the first photodiode detection part and the second photodiode detection part are the same. The first photodiode detection unit receives the reflected light signal and converts it into a second instantaneous reflected optoelectronic signal U 10 , the second photodiode detection unit receives the transmitted light signal and converts it into a second instantaneous transmitted optoelectronic signal U 20 , the signal acquisition and analysis module receives the second instantaneous reflected optoelectronic signal U 10 , the second instantaneous transmitted optoelectronic signal U 20 , and calculates the means U 10 , U 20 of the second instantaneous reflected optoelectronic signal U 10avg , U 20avg within a short time period T1, and defines the initial value K0 = U 20avg / U 10avg ; The signal acquisition and analysis module judges the air flow pollution situation at the air inlet end of the laser head according to the change range of the ratio S relative to the initial value K0, the short-term T1 fluctuation amplitude percentage Y1 and the long-term T2 fluctuation amplitude percentage Y2 of the ratio S. The T2 time period consists of N T1 time periods. Within the short-term T1 time period range, the short-term fluctuation amplitude ratio of the ratio S is Y1. ，（1） where U 2max is the maximum value of the first instantaneous transmitted optoelectronic signal U2 received by the second optoelectronic diode detection unit within the time period T1, U 2min is the minimum value of the first instantaneous transmitted optoelectronic signal U2 received by the second optoelectronic diode detection unit within the time period T1, U 2avg is the average value of the first instantaneous transmitted optoelectronic signal U2 received by the second optoelectronic diode detection unit within the time period T1; Within the long-term T2 time period range, the long-term fluctuation amplitude ratio of the ratio S is Y2. ，（2） Where U 2avg-max is the maximum value of the means U of N short-time first transmitted optoelectronic signals received by the second optoelectronic diode detection unit within the long time period T2, 2avg and U 2avg-min is the minimum value of the means U of N short-time first transmitted optoelectronic signals received by the second optoelectronic diode detection unit within the long time period T2. 2avg ​ 2. The air flow pollution detection device for the air inlet end of a laser head according to claim 1, wherein, The pollution detection device further includes a protection window. The protection window is arranged between the beam splitter and the second photodiode detection part. The air flow is output from the air outlet end, passes between the beam splitter and the protection window, and then enters the air inlet end of the laser head.

3. The air flow pollution detection device at the air inlet end of the laser head according to claim 1, characterized in that, The light-emitting diode part includes an output mirror for changing the light beam output by the light-emitting diode into a parallel light beam.

4. The air flow pollution detection device for the air inlet end of a laser head according to claim 1, characterized in that, The beam splitter is a wedge mirror. Along the light beam propagation direction of the light-emitting diode, the wedge mirror sequentially includes a first plane mirror surface and a second plane mirror surface, and the included angle between the two plane mirror surfaces is 5° - 60°.

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

6. The air flow pollution detection device for the air inlet end of a laser head according to claim 1, wherein, The short-time T1 time period is in the time range of 1 ms - 1 s, and the long-time T2 time period is in the time range of 1 min - 5 min.

7. The air flow pollution detection device for the air inlet end of a laser head according to claim 1, characterized in that When the short-time fluctuation amplitude ratio Y1 of the ratio S exceeds the range of [0, 5%], the signal acquisition and analysis module determines that the gas source and the laser processing head need to be cleaned.

8. The air flow pollution detection device for the air inlet end of a laser head according to claim 1, characterized in that, The short-time fluctuation amplitude ratio Y1 of the ratio S does not exceed the range of [0, 5%], and the long-time fluctuation amplitude ratio Y2 does not exceed the range of [0, 5%]. (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 in 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.

9. The air flow pollution detection device for the air inlet end of a laser head according to claim 1, characterized in that When the short-time fluctuation amplitude ratio Y1 of the ratio S does not exceed the range of [0, 5%], the long-time fluctuation amplitude ratio Y2 exceeds the range of [0, 5%], 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 in the range of S < [0.8, 1] × K0, the signal acquisition and analysis module determines that the pollution detection device and the laser processing head need to be cleaned.

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