Laser cutting head, laser processing equipment and detection method

Abstract

The present invention provides a laser cutting head, laser processing equipment and detection method, comprising a cutting head body and a nozzle, wherein the cutting head body is used to guide a laser beam to the nozzle, the nozzle has an opening for outputting the laser beam to a processing area, and a first annular base, a second annular base, a third annular base, a light detector and a filter are arranged in the cutting head body; in a light-emitting state, the laser beam passes through the first annular base, the second annular base and the third annular base in sequence; the inner wall of the first annular base is provided with a first annular inclined surface along the circumferential direction; the inner wall of the second annular base is provided with a second annular inclined surface along the circumferential direction; the diameter of the lower edge of the first annular inclined surface is smaller than the diameter of the upper edge of the second annular inclined surface; at least one accommodating cavity is provided inside the third annular base, and a light detector is installed in the accommodating cavity; the accommodating cavity is connected to the outer side of the third annular base through a light inlet; and the filter is detachably connected to the third annular base.

Description

Technical Field

[0001] The present invention relates to the field of processing technology, and more particularly, to a laser cutting head, laser processing equipment and a detection method. Background Art

[0002] With the continuous advancement of laser technology, the use of laser equipment in mechanical processing is becoming increasingly common. Laser processing equipment projects a laser beam onto the surface of an object, utilizing high temperatures to perform operations such as cutting, welding, and drilling. Due to the laser beam's narrow reach, laser processing technology has been applied to many precision mechanical manufacturing processes.

[0003] When using laser processing, timely and accurate detection of the workpiece's processing status is a crucial step. Existing laser processing equipment and methods generally rely on technicians to determine the workpiece's processing status based on their experience, or set a fixed processing time based on the specific process, and then execute the processing steps according to the set processing time. The technician's judgment of the workpiece's processing status is largely subjective, influenced by personal experience and potential deviations in attention, resulting in generally low accuracy. Directly executing the process steps according to the set time lacks timely detection of the workpiece's processing status.

[0004] Existing laser processing equipment and methods are unable to detect the processing status of the workpiece in a timely and accurate manner during the processing. Summary of the Invention

[0005] The present invention provides a laser cutting head, laser processing equipment and a detection method to solve the problem that the existing laser processing equipment and methods cannot detect the processing status of a workpiece in a timely and accurate manner during the processing.

[0006] According to a first aspect of the present invention, there is provided a laser cutting head, comprising a cutting head body and a nozzle, wherein the cutting head body is used to guide a laser beam to the nozzle, the nozzle having an opening for outputting the laser beam to a processing area, and wherein a first annular base, a second annular base, a third annular base, a light detector, and a filter are disposed within the cutting head body;

[0007] The first annular base, the second annular base, and the third annular base are coaxially arranged, and in the light-emitting state, the laser beam passes through the first annular base, the second annular base, and the third annular base in sequence;

[0008] The inner wall of the first annular base is provided with a first annular inclined surface along the circumferential direction, and the first annular inclined surface is inclined downward;

[0009] The inner wall of the second annular base is provided with a second annular inclined surface along the circumferential direction, and the second annular inclined surface is inclined downward;

[0010] The diameter of the lower edge of the first annular inclined surface is smaller than the diameter of the upper edge of the second annular inclined surface;

[0011] At least one accommodating cavity is provided inside the third annular base, and the light detector is installed in the accommodating cavity; the accommodating cavity is connected to the outside of the third annular base through a light inlet, and the light inlet is vertically oriented toward the second annular inclined surface;

[0012] The optical filter is detachably connected to the third annular base, and the optical filter is shielded from the light inlet after connection;

[0013] The first annular inclined surface, the second annular inclined surface, the optical filter and the light entrance are configured such that a light signal from the processing area near the opening can be reflected in sequence by the first annular inclined surface and the second annular inclined surface, and transmitted to the corresponding light detector through the light entrance and the optical filter, wherein the light signal in the processing area is generated by the laser beam acting on a workpiece in the processing area.

[0014] Optionally, the third annular base includes a bottom plate and an annular cover; the annular cover is covered on the bottom plate to form the at least one accommodating cavity between the annular cover and the bottom plate.

[0015] Optionally, the laser cutting head further includes an annular connecting member, and the filter is connected to the light inlet via the annular connecting member.

[0016] Optionally, the filter element includes a first filter for filtering the light signal of a first target band in the light signal of the processing area, and the light signal of the first target band includes the light signal of the laser beam working band; the light detector is connected to the processing unit, and the light detector is used to collect light intensity information of the light signal after filtering by the first filter, and the processing unit is used to determine that the perforation of the workpiece is completed if the light intensity information is lower than a first preset value.

[0017] Optionally, the first optical filter is a low-pass filter, and the low-pass filter is specifically used to filter optical signals in a wavelength band above 950nm.

[0018] Optionally, the filter element includes a second filter for filtering the light signal of the processing area and retaining the light signal of the second target band, the light signal of the second target band includes the luminous signal of the plasma generated by laser processing, the light detector is connected to the processing unit, the light detector is used to collect light intensity information of the light signal of the processing area after filtering by the second filter, and the processing unit is used to determine that the processing effect of the processing area is poor if the light intensity information is higher than a second preset value.

[0019] Optionally, the second optical filter is a bandpass filter, and the bandpass filter is specifically used to retain optical signals in the 400nm-500nm band.

[0020] According to a second aspect of the present invention, there is provided a laser processing device comprising the laser cutting head according to the first aspect and its optional solutions.

[0021] According to a third aspect of the present invention, a laser processing perforation detection method is provided, which is applied to a control end, and the method includes:

[0022] When using the laser cutting head involved in the first aspect and its optional solutions to perforate a workpiece, light intensity information collected by a light detector is obtained, wherein the light intensity information represents the intensity of the light signal in the processing area after being filtered by the filter element, the filter element is used to filter the light signal of a first target wavelength band, and the light signal of the first target wavelength band includes the light signal of the working wavelength band of the laser beam;

[0023] If the light intensity information is lower than a first preset value, it is determined that the perforation of the workpiece is completed.

[0024] According to a fourth aspect of the present invention, a laser processing quality detection method is provided, the method comprising:

[0025] When processing a workpiece using the laser cutting head according to the first aspect and its optional solutions, light intensity information collected by the light detector is obtained, the light intensity information representing the intensity of the light signal in the processing area after filtering by the filter, the filter being used to filter the light signal in the processing area and retain the light signal in a second target wavelength band, the light signal in the second target wavelength band including the luminous signal of the plasma generated by the laser processing;

[0026] If the light intensity information is higher than a second preset value, it is determined that the processing effect of the processing area is poor.

[0027] The present invention provides a laser cutting head, laser processing equipment and detection method, wherein the laser cutting head includes a cutting head body and a nozzle, wherein a first annular base, a second annular base, a third annular base, a light detector and a filter are arranged in the cutting head body; the first annular base, the second annular base and the third annular base are coaxially arranged, the inner wall of the first annular base is provided with a first annular inclined surface along the circumferential direction, the inner wall of the second annular base is provided with a second annular inclined surface along the circumferential direction, and the diameter of the lower edge of the first annular inclined surface is smaller than the diameter of the upper edge of the second annular inclined surface, and the first annular inclined surface and the second annular inclined surface are configured to transmit the light signal from the processing area near the opening through the first annular inclined surface and the second annular inclined surface. The surface reflection is a vertically propagating light signal. The accommodating cavity of the third annular base is connected to the outside of the third annular base through the light inlet, and the light inlet is vertically oriented toward the second annular inclined surface to receive the vertically propagating light signal reflected by the second annular inclined surface. By setting the third annular base, most of the stray light in the cutting head body can be prevented from reaching the light detector, reducing the amount of stray light received by the light detector. By setting the first annular inclined surface and the second annular inclined surface, the processing area light signal is reflected twice before entering the light inlet, reducing the entry of stray light. In the case of a small annular base, it is ensured that the light inlet can enter a sufficient amount of effective light (which can be understood as the amount of light from the processing area light signal near the opening). It can be seen that the laser cutting head provided in the present invention suppresses the amount of stray light while ensuring that the light inlet can enter a sufficient amount of effective light, improves the signal-to-noise ratio of the signal received by the light detector, and improves the accuracy of the detection of the processing status of the workpiece. The laser cutting head provided in the present invention can detect the processing status of the workpiece in a timely and accurate manner during the processing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 It is a schematic diagram of the operation of laser processing equipment and workpiece detection;

[0030] Figure 2 is a schematic diagram of a laser cutting head in one embodiment of the present invention;

[0031] Figure 3 is a cross-sectional view of a laser cutting head according to an embodiment of the present invention;

[0032] Figure 4 is a cross-sectional view of the inner annular base of the cutting head body according to one embodiment of the present invention;

[0033] Figure 5 2 is a schematic diagram showing the effect of an optical signal being reflected twice in one embodiment of the present invention;

[0034] Figure 6a This is a schematic diagram of the structure of the third ring matrix in one embodiment of the present invention. Figure 1 ;

[0035] Figure 6b This is a schematic diagram of the structure of the third ring matrix in one embodiment of the present invention. Figure 2 ;

[0036] Figure 7 This is a comparison chart of the measured light signal of the laser beam perforation;

[0037] Figure 8 is a filtering characteristic curve diagram of a first filter selected in one embodiment of the present invention;

[0038] Figure 9 is a flow chart of a laser processing perforation detection method in one embodiment of the present invention;

[0039] Figure 10 It is the light intensity information change diagram during the perforation process;

[0040] Figure 11 4 is a flow chart of a laser processing quality detection method in one embodiment of the present invention.

[0041] Description of reference numerals:

[0042] 1- cutting head body;

[0043] 2-nozzle;

[0044] 201-opening;

[0045] 3-Workpiece;

[0046] 4-Spectrometer;

[0047] 5- Host computer;

[0048] 6-first cyclic base;

[0049] 601-first annular inclined surface;

[0050] 7-second cyclic base;

[0051] 701- second annular inclined surface;

[0052] 8-third cyclic base;

[0053] 801- annular cover;

[0054] 802-baseboard;

[0055] 803-accommodation cavity;

[0056] 804-light entrance;

[0057] 9-light detector;

[0058] 10- filter;

[0059] 11- first mirror surface;

[0060] 12- Second mirror;

[0061] 13- Ring connector. DETAILED DESCRIPTION

[0062] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0063] The terms "first", "second", "third", "fourth", etc. (if any) in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way are interchangeable where appropriate, so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatus.

[0064] The following specific embodiments are used to describe the technical solution of the present invention in detail. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0065] Figure 1 This is a schematic diagram of the operation of laser processing equipment and workpiece detection.

[0066] Please refer to Figure 1 , including a laser cutting head, a cutting head body 1, a nozzle 2, a workpiece 3, a spectrometer 4 and a host computer 5.

[0067] The cutting head body 1 has a laser beam channel, through which the laser beam enters the nozzle 2 below the cutting head body 1. The nozzle 2 has an opening 201 for outputting the laser beam to the processing area. The laser beam is then drawn out through the nozzle 2 and acts on the workpiece 3 in the processing area. When the laser beam acts on the workpiece 3, it generates a light signal in the processing area, which can be understood as the processing area light signal. Depending on the processing technology, the processing area light signal can include, for example, at least one of the following: a light signal of the laser beam reflected from the surface of the workpiece 3, a light signal excited by heat from the workpiece 3, and a light signal generated by plasma generated by the high temperature of the workpiece 3. Depending on the material of the workpiece 3 and the energy of the laser beam, the light signal excited by heat from the workpiece 3 and the light signal generated by plasma can exist in multiple wavelengths.

[0068] The light signal near the opening 201 of the nozzle 2 on the workpiece 3 will enter the cutting head body 1 through the opening 201. The intensity of the light in a specific wavelength band in these light signals can represent the processing status of the workpiece 3. In one example, if the intensity of the light signal in a specific wavelength band excited by the heat of the workpiece 3 decays to below a set value, it means that no material in the corresponding processing area of the workpiece 3 is irradiated by the laser beam. If the laser processing equipment performs a perforation (also known as drilling) operation, it can be considered that the perforation has been completed. In another example, if the intensity of the light signal in a specific wavelength band generated by the plasma generated by the high temperature of the workpiece 3 exceeds a set value, it means that the workpiece 3 has excessive temperature accumulation when irradiated by the laser beam. Excessive temperature accumulation can cause poor processing of the workpiece 3, such as the occurrence of cutting defects.

[0069] Based on the above content, it can be understood that by selecting the light signal of a specific wavelength band that enters the cutting head body 1 through the opening 201 and determining its intensity, it can be used to judge the processing status of the workpiece 3 (for example, whether the processing is poor, whether the perforation is completed, etc.).

[0070] Because the laser beam passes through the interior of the cutting head body 1, there will be strong stray light. This stray light will reduce the signal-to-noise ratio of the effective signal received by the light detector 9 (which can be understood as the light signal in the specific wavelength band mentioned above). Therefore, how to suppress stray light from entering the light detector 9 and improve the signal-to-noise ratio of the effective signal received by the light detector 9 is the key to improving the accuracy of the processing status detection of the workpiece 3.

[0071] Figure 2 Schematic diagram of a laser cutting head in one embodiment of the present invention.

[0072] Figure 3 is a cross-sectional view of a laser cutting head in one embodiment of the present invention.

[0073] Figure 4 It is a cross-sectional view of the inner annular base of the cutting head body in one embodiment of the present invention.

[0074] Please refer to Figure 2 、 Figure 3 as well as Figure 4 A laser cutting head includes a cutting head body 1 and a nozzle 2. The cutting head body 1 is used to guide the laser beam to the nozzle 2. The nozzle 2 has an opening 201 for outputting the laser beam to the processing area. A first annular base 6, a second annular base 7, a third annular base 8, a light detector 9, and a filter 10 are arranged in the cutting head body 1; the first annular base 6, the second annular base 7, and the third annular base 8 are coaxially arranged. In the light-emitting state, the laser beam passes through the first annular base 6, the second annular base 7, and the third annular base 8 in sequence; the inner wall of the first annular base 6 is provided with a first annular inclined surface 601 along the circumferential direction, and the first annular inclined surface 601 is inclined downward; the inner wall of the second annular base 7 is provided with a second annular inclined surface 701 along the circumferential direction, and the second annular inclined surface 701 is inclined downward; the diameter of the lower edge of the first annular inclined surface 601 is smaller than that of the second annular inclined surface The diameter of the upper edge of the inclined surface 701; at least one accommodating cavity 803 is provided inside the third annular base 8, and a light detector 9 is installed in the accommodating cavity 803; the accommodating cavity 803 is connected to the outside of the third annular base 8 through the light inlet 804, and the light inlet 804 is vertically facing the second annular inclined surface 701; the filter 10 is detachably connected to the third annular base 8, and the filter 10 is blocked by the light inlet 804 after connection; the first annular inclined surface 601, the second annular inclined surface 701, the filter 10 and the light inlet 804 are configured as follows: the optical signal from the processing area near the opening 201 can be reflected in sequence by the first annular inclined surface 601 and the second annular inclined surface 701, and transmitted to the corresponding light detector 9 through the light inlet 804 and the filter 10, wherein the optical signal in the processing area is generated by the laser beam acting on the workpiece 3 in the processing area.

[0075] Please refer to Figure 4 In the laser cutting head provided in this embodiment, a first annular base 6, a second annular base 7, and a third annular base 8 are provided in the cutting head body 1. The first annular base 6, the second annular base 7, and the third annular base 8 are coaxially arranged, that is, the axes of the three annular bodies are the same axis. The hollow space of the first annular base 6, the second annular base 7, and the third annular base 8 is for the laser beam to pass through (which can be understood as part of the above-mentioned laser beam channel). In the light-emitting state, the laser beam passes through the first annular base 6, the second annular base 7, and the third annular base 8 in sequence. It is assumed here that the direction of the laser beam is from top to bottom. In this embodiment, the first annular base 6 is above the second annular base 7, and the second annular base 7 is above the third annular base 8. In this embodiment, the first annular base 6, the second annular base 7, and the third annular base 8 are further coaxially arranged with the laser beam.

[0076] The fact that the diameter of the lower edge of the first annular inclined surface 601 is smaller than the diameter of the upper edge of the second annular inclined surface 701 can be understood as meaning that the upper edge of the second annular inclined surface 701 is further away from the axis than the lower edge of the first annular inclined surface 601. In other words, while the second annular inclined surface 701 is below the first annular inclined surface 601, the second annular inclined surface 701 as a whole extends further outward than the first annular inclined surface 601. This ensures that the second annular inclined surface 701 does not block the processing area optical signal entering from below from being transmitted to the first annular inclined surface 601. The first annular inclined surface 601 reflects the processing area optical signal to an opposing area on the second annular inclined surface 701. This can be understood as meaning that the reflection area on the first side of the first annular inclined surface 601 reflects the processing area optical signal to the reflection area on the second side of the second annular inclined surface 701, where the first side and the second side are opposing sides. For example, the reflection area on the left side of the first annular inclined surface 601 reflects the processing area light signal to the reflection area on the right side of the second annular inclined surface 701, and the reflection area on the left side of the second annular inclined surface 701 receives the processing area light signal reflected by the reflection area on the right side of the first annular inclined surface 601.

[0077] The light detector 9 in this embodiment can be understood as a device capable of sensing or recording light signals, such as a photoelectric sensor, which can convert light signals into corresponding electrical signals and further characterize the relative intensity of the light signals.

[0078] In this embodiment, the first annular inclined surface 601 and the second annular inclined surface 701 can be understood as reflective surfaces. Light signals from the processing area near the opening 201 are reflected by the first annular inclined surface 601 onto the second annular inclined surface 701. The second annular inclined surface 701 then reflects the light signals into vertically propagating signals. Based on the aforementioned orientation assumption, the second annular inclined surface 701 reflects the light signals from the processing area into light signals that propagate from top to bottom.

[0079] The light inlet 804 is vertically oriented toward the second annular inclined surface 701 (i.e., the light inlet 804 faces upward), thereby directly receiving the light signal reflected by the second annular inclined surface 701. Before entering the light inlet 804, the light signal reflected by the second annular inclined surface 701 is filtered by the optical filter 10. The optical filter 10 determines that the light signal of a predetermined wavelength band enters the light inlet 804. The light signal of the predetermined wavelength band is associated with the processing status of the workpiece 3 in the processing area.

[0080] In this embodiment, the double reflection method of the first annular inclined surface 601 and the second annular inclined surface 701 can reduce the entry of stray light, and also ensure that sufficient effective light can enter the light entrance 804 when the annular base is small.

[0081] Figure 5FIG. 1 is a schematic diagram showing the effect of an optical signal being reflected twice in one embodiment of the present invention.

[0082] Please refer to Figure 5 , wherein the first mirror surface 11 is equivalent to the first annular inclined surface 601, and the second mirror surface 12 is equivalent to the second annular inclined surface 701. Figure 5 It can be seen that after the processing area light signal from the nozzle opening 201 is reflected twice, part of the stray light will deviate from the receiving range of the light detector 9, while the light detector 9 can also receive sufficient processing area light signals.

[0083] By providing the third annular base 8 in this embodiment, most stray light within the cutting head body 1 can be prevented from entering the light inlet 804, thereby also reducing the amount of stray light received by the light detector 9. By providing the first annular inclined surface 601 and the second annular inclined surface 701, the light signal from the processing area enters the light inlet 804 after two reflections, thereby reducing the entry of stray light. Furthermore, when the annular base is relatively small, it is ensured that a sufficient amount of effective light can enter the light inlet 804. The laser cutting head provided in this embodiment suppresses the amount of stray light entering while ensuring that a sufficient amount of effective light can enter the light inlet 804, thereby improving the signal-to-noise ratio of the signal received by the light detector 9 and improving the accuracy of the detection of the processing status of the workpiece 3.

[0084] Figure 6a This is a schematic diagram of the structure of the third ring matrix in one embodiment of the present invention. Figure 1 .

[0085] Figure 6b FIG2 is a second structural diagram of the third annular base in one embodiment of the present invention.

[0086] Please refer to Figure 6a 、 Figure 6b The third annular base 8 includes a bottom plate 802 and an annular cover 801 ; the annular cover 801 covers the bottom plate 802 to form at least one accommodating cavity 803 between the annular cover 801 and the bottom plate 802 .

[0087] Please continue to refer to Figure 6a 、 Figure 6b The laser cutting head further includes an annular connector 13, through which the optical filter 10 is connected to the light inlet 804. In one embodiment, the outer wall of the annular connector 13 is detachably connected to the inner wall of the accommodating cavity 803 near the light inlet 804, and the optical filter 10 is disposed in the annular through hole of the annular connector 13.

[0088] In order to eliminate the influence of special circumstances such as the tilt of the workpiece 3, the tilt of the machine tool, and the warping of the workpiece 3 during processing on the detection, one embodiment of the present invention sets at least 4 (or 6, 8...) centrally symmetrical light detectors 9 at the same horizontal position with the main light path as the center (which can be understood as the optical axis of the laser beam). The above influences can be eliminated by averaging multiple groups of data.

[0089] In one embodiment, the filter element 10 includes a first filter for filtering the light signal of the first target band in the light signal of the processing area, and the light signal of the first target band includes the light signal of the laser beam working band; the light detector 9 is connected to the processing unit, and the light detector 9 is used to collect the light intensity information of the light signal after filtering by the first filter, and the processing unit is used to determine that the perforation of the workpiece 3 is completed if the light intensity information is lower than the first preset value.

[0090] In this embodiment, the light detector 9 may be a photoelectric sensor.

[0091] In this embodiment, the processing unit can be understood as a device that can receive light intensity information and perform logical operations.

[0092] Taking the actual measurement results of 1080nm laser beam perforation as an example, refer to Figure 7 , Figure 7 This is a comparison chart of the measured light signals of laser beam perforation. It can be seen that before the hole is penetrated (corresponding to the upper half of the figure), the light detected in the cutting head body 1 is distributed in various wavelength bands. The light intensity is strongest near the 1080nm band. The source of this part of the light is the reflection of the laser irradiated on the workpiece 3 (laser wavelength 1080nm). The other bands are mainly divided into two parts, one part is the visible light generated by the spark burst of the laser irradiation on the workpiece 3, and the other part is the high-frequency light excited after the workpiece 3 is heated. After the perforation is completed (corresponding to the lower half of the figure), the light detected in the cutting head body 1 is all in the 1080nm band. The light measured during this time is actually the stray light emitted by the laser itself and the reflection of the optical lens inside the cutting head body 1, so the wavelength can be consistent with the laser.

[0093] The test results reveal a difference in the distribution of optical signals within the cutting head body 1 before and after the hole is punched: before the hole is punched, there are optical signals of various wavelengths, while after the hole is punched, there are only optical signals near the 1080nm band. Based on this difference, one embodiment of the present invention selects an appropriate low-pass filter whose transmittance characteristics can filter out light in the 1080nm band. This results in the signal received by the photoelectric sensor within the cutting head body 1 being: before the hole is punched (i.e., there are the aforementioned optical signals except for those near the 1080nm band), and after the hole is punched, there is no signal. The presence or absence of a signal is determined by comparing it with a first preset value. If the light intensity is greater than the first preset value, it is considered to be a signal; otherwise, there is no signal.

[0094] In one embodiment, the first filter is a filter that filters wavelengths above 950 nm. Figure 8 , Figure 8 This is a filtering characteristic curve diagram of the first filter selected in one embodiment of the present invention, wherein the curve indicated by the arrow is the transmittance curve. It can be seen that light above 950nm is filtered, and the transmittance of light above the nominal wavelength of 950nm of the lens is less than 0.1%.

[0095] In one embodiment, the filter element 10 includes a second filter for filtering the optical signal of the processing area and retaining the optical signal of the second target band. The optical signal of the second target band includes the luminous signal of the plasma generated by laser processing. The light detector 9 is connected to the processing unit. The light detector 9 is used to collect the light intensity information of the optical signal of the processing area after filtering by the second filter. The processing unit is used to determine that the processing effect of the processing area is poor if the light intensity information is higher than a second preset value.

[0096] Laser cutting is a process in which the workpiece 3 is continuously heated, melted, and cut through by laser heating. When the processing is normal, the entire process is continuously cycled and there is no large amount of heat accumulation. When the processing is poor and the workpiece cannot be cut through, heat will continue to accumulate in the molten part to generate high temperature, and then generate plasma. The appearance of plasma is one of the manifestations of poor processing effect. At the same time, plasma will also cause the laser to refract, affecting the focal position, and further deteriorating the processing effect. When plasma appears, blue light will be generated, and its spectrum is in the 450nm-495nm band. In one embodiment, the second filter is a bandpass filter, and the bandpass filter is specifically used to retain the light signal in the 400nm-500nm band.

[0097] An embodiment of the present invention further provides a laser processing device, including the laser cutting head involved in the above optional solution.

[0098] Figure 9 This is the process of the laser processing perforation detection method in one embodiment of the present invention Figure 1 .

[0099] Please refer to Figure 9 An embodiment of the present invention further provides a laser processing perforation detection method, which is applied to a control end and includes:

[0100] S11: When perforating a workpiece 3 using the laser cutting head involved in the above optional solution, light intensity information collected by the light detector 9 is obtained, where the light intensity information represents the intensity of the light signal in the processing area after being filtered by the filter 10. The filter 10 is used to filter the light signal of the first target wavelength band in the light signal in the processing area. The light signal of the first target wavelength band includes the light signal of the working wavelength band of the laser beam.

[0101] S12: If the light intensity information is lower than the first preset value, it is determined that the perforation of the workpiece 3 is completed.

[0102] Please continue to refer to Figure 8 Taking the actual measurement results of laser beam perforation in the 1080nm band as an example, we specifically select filters that filter wavelengths above 950nm (including the laser beam working band).

[0103] Figure 10 It is a diagram of the light intensity change during the perforation process.

[0104] Please refer to Figure 10 , Figure 10 The vertical axis represents sensor data, and the horizontal axis represents time. Point A marks the start of perforation, and Point B marks the completion of perforation. To prevent misjudgments and increase accuracy, a delay is added after perforation completion is detected, representing the time between Points A and C. If the sensor data remains unchanged during this delay, perforation is considered complete.

[0105] Figure 10 It can be divided into three stages:

[0106] In the first stage, when the laser device does not start working and the laser beam does not irradiate the workpiece 3, the value representing the intensity is lower than 500.

[0107] In the second stage, when the laser device starts working and the laser beam is irradiated on the workpiece 3, the value representing the intensity is greater than 2500.

[0108] In the third stage, when the workpiece 3 is perforated, the laser beam passes through the processed hole, and the value representing the intensity is less than 500.

[0109] From the above analysis, it can be seen that by analyzing the changes in light intensity information, it is possible to accurately determine whether the perforation work is completed. Figure 10It can also be seen that the difference in light intensity before and after perforation is quite large, which makes it very clear that a judgment can be made. The reason why the light detector 9 (for example, a photoelectric sensor) can detect such a significant difference is mainly because the internal structure of the laser cutting head provided in the embodiment of the present invention, that is, the structural and positional design of the first annular base 6, the second annular base 7, and the third annular base 8, suppresses stray light while ensuring sufficient effective light input, thereby improving the signal-to-noise ratio of the light detector 9.

[0110] Figure 11 4 is a flow chart of a laser processing quality detection method in one embodiment of the present invention.

[0111] Please refer to Figure 11 An embodiment of the present invention further provides a laser processing quality detection method, the method comprising:

[0112] S11: When processing a workpiece 3 using the laser cutting head involved in the above optional solution, light intensity information collected by the light detector 9 is obtained, where the light intensity information represents the intensity of the light signal in the processing area after being filtered by the filter 10. The filter 10 is used to filter the light signal in the processing area and retain the light signal in the second target wavelength band. The light signal in the second target wavelength band includes the luminescence signal of the plasma generated by the laser processing;

[0113] S12: If the light intensity information is higher than the second preset value, it is determined that the processing effect of the processing area is poor.

[0114] Laser cutting is a process in which the workpiece 3 is continuously heated, melted, and cut through by means of laser heating. When the processing is normal, the entire process is continuously cycled, and a large amount of heat will not accumulate. When the processing is poor and the workpiece cannot be cut through, heat will continuously accumulate in the molten part to generate high temperature, thereby generating plasma. The appearance of plasma is one of the manifestations of poor processing effect. At the same time, plasma will also cause the laser to refract, affecting the focal position, thereby further deteriorating the processing effect. When plasma appears, blue light will be generated, and its spectrum is in the 450nm-495nm band. In one embodiment, a bandpass filter is specifically used to select the light signal in the 400nm-500nm band.

[0115] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser cutting head, comprising a cutting head body and a nozzle, wherein the cutting head body is used to guide a laser beam to the nozzle, and the nozzle has an opening for outputting the laser beam to a processing area, characterized in that: The cutting head body is provided with a first annular base, a second annular base, a third annular base, a light detector, and a filter; The first annular base, the second annular base, and the third annular base are coaxially arranged, and in the light-emitting state, the laser beam passes through the first annular base, the second annular base, and the third annular base in sequence; The inner wall of the first annular base is provided with a first annular inclined surface along the circumferential direction, and the first annular inclined surface is inclined downward; The inner wall of the second annular base is provided with a second annular inclined surface along the circumferential direction, and the second annular inclined surface is inclined downward; The diameter of the lower edge of the first annular inclined surface is smaller than the diameter of the upper edge of the second annular inclined surface; At least one accommodating cavity is provided inside the third annular base, and the light detector is installed in the accommodating cavity; the accommodating cavity is connected to the outside of the third annular base through a light inlet, and the light inlet is vertically oriented toward the second annular inclined surface; The optical filter is detachably connected to the third annular base, and the optical filter is shielded from the light inlet after connection; The first annular inclined surface, the second annular inclined surface, the optical filter and the light entrance are configured such that a light signal from the processing area near the opening can be reflected in sequence by the first annular inclined surface and the second annular inclined surface, and transmitted to the corresponding light detector through the light entrance and the optical filter, wherein the light signal in the processing area is generated by the laser beam acting on a workpiece in the processing area.

2. The laser cutting head according to claim 1, characterized in that: The third annular base includes a bottom plate and an annular cover; the annular cover is covered on the bottom plate to form the at least one accommodating cavity between the annular cover and the bottom plate.

3. The laser cutting head according to claim 1 or 2, characterized in that: It also includes an annular connecting piece, and the filter is connected to the light entrance through the annular connecting piece.

4. The laser cutting head according to claim 1 or 2, characterized in that: The filter element includes a first filter for filtering the light signal of a first target band in the light signal of the processing area, and the light signal of the first target band includes the light signal of the working band of the laser beam; the light detector is connected to the processing unit, and the light detector is used to collect light intensity information of the light signal of the processing area after filtering by the first filter, and the processing unit is used to determine that the perforation of the workpiece is completed if the light intensity information is lower than a first preset value.

5. The laser cutting head according to claim 4, characterized in that: The first optical filter is a low-pass filter, which is specifically used to filter optical signals in a wavelength band above 950 nm.

6. The laser cutting head according to claim 1 or 2, characterized in that: The filter element includes a second filter for filtering the optical signal of the processing area and retaining the optical signal of the second target band. The optical signal of the second target band includes the luminous signal of the plasma generated by laser processing. The light detector is connected to the processing unit. The light detector is used to collect light intensity information of the optical signal of the processing area after filtering by the second filter. The processing unit is used to determine that the processing effect of the processing area is poor if the light intensity information is higher than a second preset value.

7. The laser cutting head according to claim 6, characterized in that: The second optical filter is a bandpass filter, and the bandpass filter is specifically used to retain optical signals in the 400nm-500nm band.

8. A laser processing device, characterized in that: The laser cutting head comprises the laser cutting head according to any one of claims 1 to 7.

9. A laser processing perforation detection method, applied to a control end, characterized in that: The method comprises: When perforating a workpiece using the laser cutting head according to any one of claims 1 to 3, light intensity information collected by a light detector is obtained, the light intensity information representing the intensity of the light signal in the processing area after being filtered by the filter, the filter being used to filter the light signal of a first target wavelength band in the light signal in the processing area, the light signal of the first target wavelength band including the light signal of the working wavelength band of the laser beam; If the light intensity information is lower than a first preset value, it is determined that the perforation of the workpiece is completed.

10. A laser processing quality detection method, characterized in that: The method comprises: When processing a workpiece using the laser cutting head according to any one of claims 1 to 3, light intensity information collected by the light detector is obtained, the light intensity information representing the intensity of the light signal in the processing area after being filtered by the filter, the filter being used to filter the light signal in the processing area and retain the light signal in a second target wavelength band, the light signal in the second target wavelength band including the luminous signal of the plasma generated by the laser processing; If the light intensity information is higher than a second preset value, it is determined that the processing effect of the processing area is poor.

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