Pseudo soldering detection method and related equipment

Abstract

The invention relates to the field of laser processing. The embodiment of the invention discloses a pseudo soldering detection method and related equipment. The method comprises the steps that when laser machining is carried out on a sheet material, infrared light signals radiated by a target weld joint in the laser welding process and after the laser welding process are finished are received, the infrared light signals are radiated after machining laser acts on the sheet material, and the infrared light signals are received in the coaxial direction through a light emitting path of the machining laser; the industrial control computer obtains an electric signal corresponding to the infrared light signal generated by the target welding seam in a first time period, and the starting moment of the first time period is not earlier than the moment of forming the complete target welding seam; and determining whether pseudo soldering exists in the target weld according to the electric signal corresponding to the infrared light signal. By adopting the embodiment of the invention, whether pseudo soldering exists in the welding seam generated in the sheet welding process can be realized.

Description

Technical Field

[0001] The present application relates to the field of laser processing technology, and in particular to a method for detecting cold welds and related equipment. Background Art

[0002] In the 3C field, laser welding of metal sheets is the main way to connect positive and negative materials of button batteries, mobile phone batteries, laptop batteries, etc. In order to ensure the quality of welding, it is necessary to analyze and inspect the results of laser welding, and the analysis of welds includes identifying welding defects.

[0003] The identification of laser welding defects in the 3C field is a big challenge. Currently, the market often uses a top view to inspect the welds purely visually, but it is usually not possible to identify whether there is a cold weld. If there is a cold weld in the electrode material, it cannot guarantee continuous and stable electrical contact of the battery during operation, which is a big problem. Therefore, cold weld detection in the thin-film laser welding process is particularly important. Summary of the invention

[0004] The embodiment of the present application proposes a welding cold joint detection method and related equipment, and the embodiment of the present application can be used to determine whether there is a cold joint in the weld produced during the sheet welding process.

[0005] This application is implemented using the following technical solutions.

[0006] In a first aspect, an embodiment of the present application provides a method for detecting a cold weld, comprising:

[0007] When laser processing is performed on a thin sheet material, an infrared light signal radiated by a target weld during and after the laser welding process is completed is received, wherein the infrared light signal is radiated after the processing laser acts on the thin sheet material, and the infrared light signal is received in a coaxial direction with the light output path of the processing laser;

[0008] The industrial computer obtains an electrical signal corresponding to an infrared light signal generated by the target weld in the first period, wherein the start time of the first period is not earlier than the time when the target weld is completely formed; and determines whether there is a virtual weld in the target weld according to the electrical signal corresponding to the infrared light signal. The target weld is formed by laser processing of a thin sheet material.

[0009] Furthermore, the industrial control computer is also used to display the electrical signal corresponding to the infrared light signal generated by the target weld in the first time period.

[0010] The thin sheet material refers to a material having a thickness less than a preset thickness. In one example, the thin sheet material refers to a material having a thickness less than 0.5 mm.

[0011] After the sheet material is welded, the energy of the infrared light signal radiated by the weld with or without a cold weld is different. Therefore, the infrared light signal radiated by the weld after welding is completed is detected to determine whether the weld has a cold weld.

[0012] In combination with the first aspect, in a possible implementation, the industrial control computer determines whether there is a cold weld in the target weld according to the electrical signal corresponding to the infrared light signal. Specifically, the electrical signal curve corresponding to the infrared light signal determines whether there is a cold weld in the target weld.

[0013] In combination with the first aspect, in a possible implementation, the industrial control computer determines whether there is a cold weld in the target weld according to the electrical signal curve corresponding to the infrared light signal, including:

[0014] The industrial control computer obtains the average offset of the infrared light signal based on the electrical signal curve corresponding to the infrared light signal and the reference center line of the infrared light signal; the industrial control computer determines whether there is a cold weld in the target weld based on the average offset of the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the average offset of the infrared light signal exceeds the preset offset range, it is determined that there is a cold weld in the target weld.

[0015] The average offset of the infrared light signal can be regarded as the offset of the electrical signal corresponding to the infrared light signal relative to the reference center line of the infrared light signal.

[0016] In combination with the first aspect, in a possible implementation, the electric signal curve corresponding to the infrared light includes a plurality of first points, the reference center line includes a plurality of second points, the plurality of first points correspond to the plurality of second points in time, and the industrial control computer obtains an average offset of the infrared light signal according to the electric signal corresponding to the infrared light signal and the reference center line of the infrared light signal, including:

[0017] The industrial control computer calculates the absolute value of the difference between the amplitude represented by each of the multiple first points and the amplitude represented by the second point corresponding to each first point in time; the industrial control computer adds and averages the absolute values ​​of the calculated multiple differences to obtain the average offset of the infrared light signal.

[0018] In combination with the first aspect, in a possible implementation, the preset offset range is [-μ-4σ, μ+4σ]; wherein μ and σ are the mean and standard deviation of the average offset of the electrical signal corresponding to the infrared light signal generated in the second time period by multiple complete welds without false welds obtained in the historical laser processing process; the starting time of the second time period is no earlier than the time when a complete weld without false welds is formed.

[0019] By determining the preset offset range based on the mean and standard deviation of the electrical signal corresponding to the infrared light signal generated in the second time period by multiple complete welds without cold welds obtained in the historical laser processing process, and then using the preset offset range to judge whether there is a cold weld, an accurate judgment result can be obtained.

[0020] In combination with the first aspect, in a possible implementation, the industrial control computer determines whether there is a cold weld in the target weld according to the electrical signal curve corresponding to the infrared light signal, including:

[0021] The industrial control computer obtains the upper limit value of the infrared light signal based on the electrical signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal; the industrial control computer determines whether there is a cold weld in the target weld based on the upper limit value of the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the upper limit value of the infrared light signal is higher than the upper limit threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0022] In combination with the first aspect, in a possible implementation, the electric signal curve corresponding to the infrared light signal includes a plurality of first points, the reference upper edge line includes a plurality of third points, the plurality of first points correspond to the plurality of third points in time, and the industrial control computer obtains an upper limit value of the infrared light signal according to the electric signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, including:

[0023] The industrial control computer calculates the difference between the amplitude represented by each of the multiple first points and the amplitude represented by the third point corresponding to the first point in time to obtain multiple differences; the industrial control computer determines the maximum value of the multiple differences as the upper limit value of the infrared light signal.

[0024] In combination with the first aspect, in a possible implementation, the reference center line of the infrared light signal includes a plurality of second points, the reference upper edge line includes a plurality of third points, the plurality of second points correspond to the plurality of third points, and the method of this embodiment further includes:

[0025] The industrial computer calculates the difference between the amplitude represented by each of the plurality of third points and the amplitude represented by the second point corresponding to the third point in time to obtain a plurality of differences; and determines the maximum value of the plurality of differences as the upper limit threshold.

[0026] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than the energy of infrared light generated by a weld without a cold weld. Accordingly, the upper limit value of the infrared light signal generated by a weld with a cold weld is higher than the upper limit value of the infrared light signal generated by a weld without a cold weld. Therefore, after a complete target weld is formed, the upper limit value of the infrared light signal generated by the target weld is compared with the upper limit threshold to determine whether the energy of infrared light generated by the weld is higher than the energy of infrared light generated by the weld without a cold weld, thereby determining whether the target weld has a cold weld, and the judgment result obtained by this judgment method is highly accurate.

[0027] In combination with the first aspect, in a possible implementation, the industrial control computer determines whether there is a cold weld in the target weld according to the electrical signal curve corresponding to the infrared light signal, including:

[0028] The industrial control computer obtains the upper local area of ​​the infrared light signal based on the electrical signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, wherein the upper local area of ​​the infrared light signal is the area between the portion of the electrical signal curve corresponding to the infrared light signal whose amplitude is greater than the amplitude of the reference upper edge line and the reference upper edge line; the industrial control computer determines whether there is a cold weld in the target weld based on the upper local area of ​​the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the upper local area of ​​the infrared light signal is greater than the upper local area threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0029] In combination with the first aspect, in a possible implementation, the industrial control computer obtains the upper local area of ​​the infrared light signal according to the electrical signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, including:

[0030] The industrial control computer determines a first moment and a second moment, wherein the first moment is the starting moment of the first time period, and the second moment is the moment when the electric signal curve corresponding to the infrared light signal intersects with the upper reference line; the industrial control computer calculates a first integral area under the electric signal curve corresponding to the infrared light signal between the first moment and the second moment; and calculates a second integral area under the upper reference line between the first moment and the second moment; the industrial control computer determines the difference between the first integral area and the second integral area as the upper local area of ​​the infrared light signal.

[0031] In combination with the first aspect, in a possible implementation, the reference upper edge line of the infrared light signal includes a plurality of third points, the reference midline of the infrared light signal includes a plurality of second points, the plurality of third points correspond to the plurality of second points in time, and the method of this embodiment further includes:

[0032] The industrial control computer determines the starting third point and the ending third point from the reference upper edge line of the infrared light signal; wherein the starting third point is the third point corresponding in time to the starting second point, the ending third point is the third point whose amplitude is the same as the amplitude represented by the second point corresponding in time, and the starting second point is the first second point in time among the multiple second points included in the reference upper edge line corresponding to the infrared light signal; the industrial control computer calculates the third integral area of ​​the portion between the starting third point and the ending third point in the reference upper edge line of the infrared light signal, and calculates the fourth integral area of ​​the portion between the second point corresponding in time to the starting third point and the second point corresponding in time to the ending third point in the reference center line of the infrared light signal; the industrial control computer determines half of the difference between the third integral area and the fourth integral area as the upper local area threshold.

[0033] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than the energy of infrared light generated by a weld without a cold weld. Accordingly, the upper local area of ​​the infrared light signal generated by a weld with a cold weld is larger than the upper local area of ​​the infrared light signal generated by a weld without a cold weld. Therefore, after a complete target weld is formed, the upper local area of ​​the infrared light signal generated by the target weld is compared with the upper local area threshold to determine whether the energy of infrared light generated by the weld is higher than the energy of infrared light generated by the weld without a cold weld, thereby determining whether the target weld has a cold weld, and the judgment result obtained by this judgment method is highly accurate.

[0034] In combination with the first aspect, in a possible implementation, the industrial control computer determines whether there is a cold weld in the target weld according to the electrical signal curve corresponding to the infrared light signal, including:

[0035] The industrial control computer determines the slope of the infrared light signal according to the electrical signal curve corresponding to the infrared light signal; determines whether there is a cold weld in the target weld according to the slope of the infrared light signal; wherein, if the slope of the infrared light signal is greater than the slope threshold, it is determined that there is a cold weld in the target weld.

[0036] Optionally, the electrical signal curve corresponding to the infrared light signal includes a plurality of first points, and the industrial control computer determines the slope of the infrared light signal according to the electrical signal curve corresponding to the infrared light signal, including:

[0037] The industrial control computer determines a starting first point and an ending first point from a plurality of first points, wherein the amplitude represented by the starting first point is collected at the starting moment of the second time period, and the ending first point is the first point represented by an amplitude of 0; the industrial control computer determines the collection time of the starting first point and the collection time of the ending first point; the industrial control computer calculates a first difference between the amplitude represented by the starting first point and the amplitude represented by the ending first point, and calculates a second difference between the collection time of the starting first point and the collection time of the ending first point; the industrial control computer calculates a ratio of the first difference to the second difference, and determines the ratio as the slope of the infrared light signal.

[0038] Optionally, the reference center line of the infrared light signal includes a plurality of second points, the plurality of first points correspond to the plurality of second points in time, and the method of this embodiment further includes:

[0039] The industrial control computer determines a starting second point and an ending second point from a plurality of second points; wherein the starting second point is a second point in the reference center line of the infrared light signal corresponding in time to the starting first point, and the ending second point is a second point in the reference center line of the infrared light signal corresponding in time to the ending first point; the industrial control computer calculates a third difference between the amplitude represented by the starting second point and the amplitude represented by the ending second point; the industrial control computer calculates a ratio between the third difference and the second difference, and the industrial control computer determines twice the absolute value of the ratio as a slope threshold.

[0040] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than that of infrared light generated by a weld without a cold weld. Accordingly, the absolute value of the slope of the infrared light signal generated by the weld with a cold weld is greater than the absolute value of the slope of the infrared light signal generated by the weld without a cold weld. Therefore, after a complete target weld is formed, the absolute value of the slope of the infrared light signal generated by the target weld is compared with the slope threshold to determine whether the energy of infrared light generated by the weld is higher than that of infrared light generated by the weld without a cold weld, thereby determining whether the target weld has a cold weld, and the judgment result obtained by this judgment method is highly accurate.

[0041] In combination with the first aspect, in a possible implementation, the electric signal curve corresponding to the infrared light signal includes a plurality of first points, and the industrial control computer determines whether there is a cold weld in the target weld according to the electric signal curve corresponding to the infrared light signal, including:

[0042] The industrial control computer calculates an average value of the amplitude of the infrared light signal based on multiple first points, wherein the average value of the amplitude of the infrared light signal is the average value of the amplitudes represented by the multiple first points; the industrial control computer determines whether there is a cold weld in the target weld based on the average value of the amplitude of the infrared light signal; if the average value of the amplitude of the infrared light signal is higher than the mean threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0043] Optionally, the reference center line of the infrared light signal includes multiple second points, and the mean threshold is twice the average value of the amplitudes represented by the multiple second points.

[0044] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than that of infrared light generated by a weld without a cold weld. Accordingly, the average value of the amplitude of the infrared light signal generated by a weld with a cold weld is higher than that of infrared light signal generated by a weld without a cold weld. Therefore, after a complete target weld is formed, the average value of the amplitude of the infrared light signal generated by the target weld is compared with the mean threshold to determine whether the energy of infrared light generated by the weld is higher than that of infrared light generated by a weld without a cold weld, thereby determining whether the target weld has a cold weld, and the judgment result obtained by this judgment method is highly accurate.

[0045] In combination with the first aspect, in a possible implementation manner, the method of this embodiment further includes:

[0046] If it is determined that there is a cold weld in the target weld, the industrial control computer obtains the position information of the target weld; the position information of the target weld is transmitted to the laser welding system, so that the laser welding system re-processes the target weld based on the position information of the target weld.

[0047] When it is determined that a target weld has a cold weld, the laser welding system reprocesses the target weld, which is helpful to reduce the occurrence of cold welds in the target weld, thereby ensuring the quality of the target weld.

[0048] In combination with the first aspect, in a possible implementation manner, the method of this embodiment further includes:

[0049] After the target weld is formed completely, the electric signal curve corresponding to the infrared light signal generated by the target weld is displayed; and the result of whether there is a cold weld in the target weld is displayed.

[0050] By displaying the electrical signal curve corresponding to the infrared light signal generated by the target weld and displaying the result of whether there is a cold weld in the target weld, the processing personnel can know the processing quality during the processing.

[0051] In a second aspect, an embodiment of the present application provides an industrial computer, comprising an acquisition unit, a determination unit, a transceiver unit and a display unit. The acquisition unit, the determination unit, the transceiver unit and the display unit are used to implement any method provided in the first aspect.

[0052] In a third aspect, an embodiment of the present application provides an industrial control computer, comprising: a processor, the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the industrial control computer executes a method as provided in any one of the first aspects.

[0053] In a fourth aspect, an embodiment of the present application provides a laser processing control system, comprising a laser welding system, a multi-optical sensor module, a signal processing module and an industrial control computer, wherein the industrial control computer is used to execute a method as provided in any one of the first aspects.

[0054] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and the computer program enables a computer to execute a method as provided in any one of the first aspects.

[0055] In a sixth aspect, an embodiment of the present application provides a computer program product, which includes a non-transitory computer-readable storage medium storing a computer program, and the computer is operable to cause the computer to execute the method described in the first aspect or the second aspect.

[0056] It can be understood that the industrial control computer described in the second and third aspects, the laser processing control system described in the fourth aspect, the computer-readable storage medium described in the fifth aspect, or the computer program product described in the sixth aspect are all used to implement the method provided in any one of the first aspects. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments of the present invention will be briefly introduced below. 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 creative work.

[0058] Figure 1 A schematic diagram of the architecture of a laser welding cold weld detection system provided in an embodiment of the present application;

[0059] Figure 2 A schematic diagram of a flow chart of a method for detecting a cold weld provided in an embodiment of the present application;

[0060] Figure 3a This is the timing diagram for post-weld inspection;

[0061] Figure 3b It is a schematic diagram of the welding process;

[0062] Figure 4a A schematic diagram of the calculation results of the average offset provided in an embodiment of the present application;

[0063] Figure 4b A schematic diagram of an upper partial area of ​​an infrared light signal provided in an embodiment of the present application;

[0064] Figure 4c A schematic diagram of the slope of an infrared light signal provided in an embodiment of the present application;

[0065] Figure 4d A schematic diagram of a test result provided in an embodiment of the present application;

[0066] Figure 5 A schematic diagram of the structure of an industrial control computer provided in an embodiment of the present application;

[0067] Figure 6 A schematic diagram of the structure of another industrial control computer provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. 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 creative work are within the scope of protection of the present invention.

[0069] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms of "a", "said" and "the" used in the embodiments of the present application, the accompanying drawings and the claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should be understood that the term "and / or" used in this article is only a kind of association relationship describing the associated objects, indicating that there can be three relationships, for example, A and / or B, which can be represented by: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are an "or" relationship. It should be understood that although the terms "first", "second" and similar words may be used in the embodiments of the present application, they do not represent any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one" or "one" do not represent quantity restrictions, but represent the existence of at least one. The "multiple" involved in the embodiments of the present application refers to greater than or equal to two.

[0070] See also Figure 1 , Figure 1 This is a schematic diagram of the architecture of a laser welding cold weld detection system provided in an embodiment of the present application. Figure 1 As shown, the system includes a laser welding system, a multi-optical sensor module 4, a signal processing module 6 and an industrial control computer 8.

[0071] The laser welding system includes a laser 1, an optical fiber 2 and a laser processing head 3. The laser 1 is connected to the laser processing head 3 through the optical fiber 2, the multi-optical sensor module 4 is coaxially installed on the laser processing head 3, the multi-optical sensor module 4 is connected to the signal processing module 6 through the first signal line 5, the signal processing module 6 is connected to the industrial control computer 8 through the second signal line 7, and the industrial control computer 8 is connected to the laser welding system through the third signal line 12.

[0072] In this embodiment, the laser light generated by the laser 1 is transmitted to the laser processing head 3 through the optical fiber 2, and then incident on the upper plate 10 of the metal material to be processed by the laser processing head 3. The upper plate 10 absorbs the laser light and melts and solidifies to form a weld 9. The infrared light radiated by the weld 9 after welding is transmitted to the multi-optical sensor module 4 through the laser processing head 3. The multi-optical sensor module 4 can receive the infrared light signal radiated by the weld 9 after welding and convert it into an electrical signal; the electrical signal is transmitted to the signal processing module 6 through the first signal line 5, and after the signal is processed, it is transmitted to the industrial control computer 8 through the second signal line 7. The industrial control computer 8 processes and identifies the received signal to determine whether there is a virtual weld in the weld 9.

[0073] Optionally, when it is determined that there is a cold weld in the weld 9 , the position information of the weld 9 is determined, and the position information of the weld 9 is transmitted to the laser welding system through the third signal line 12 to control the laser welding system to perform repair welding on the weld 9 .

[0074] It should be pointed out here that, in thin-sheet welding, when the cold weld phenomenon occurs, the volume of the exposed part of the welding pool does not change significantly, and the infrared light signal released by the welding pool during welding (i.e., during the welding process) does not change significantly, so it is impossible to identify the cold weld defect based on the infrared light signal released by the welding pool during the welding process. In other words, the welding pool does not melt through the upper plate during the welding process, and the heat of the weld is transferred to the lower plate 11 less during the welding process. After welding (after the welding process is completed), the initial accumulated heat of the weld of the upper plate 10 will increase significantly. Therefore, in the scheme of the present application, it is determined whether the weld 9 has a cold weld based on the infrared light signal radiated by the weld 9 after welding. In other words, the infrared light signal radiated after welding is used as a feature of the cold weld to determine whether the weld 9 has the defect of a cold weld.

[0075] It should be understood that the thin sheet material in the present application refers to a material having a thickness less than a preset thickness. The thin sheet material refers to a material having a thickness less than a preset thickness, and the thickness may be between 0.01 mm and 0.6 mm. In one example, the thin sheet material may refer to a material having a thickness less than 0.5 mm. In the thin sheet welding process, the upper plate 10 is a thin sheet material. During laser processing, the laser is first irradiated onto the thin sheet material, and the thin sheet material and the welding material below are melted and then re-melted and welded into one.

[0076] The preset thicknesses of thin sheets made of different materials may be different. For example, the preset thickness of a thin sheet material with good heat dissipation performance is greater than the preset thickness of a thin sheet material with poor heat dissipation performance. For example, the preset thickness of a copper thin sheet material is within 0.15mm-0.6mm, and the preferred thickness may be 0.25mm. The preset thickness of an aluminum thin sheet material is within 0.15mm-0.6mm, and the preferred thickness may be 0.2mm. The preset thickness of a stainless steel thin sheet material is within 0.1mm-0.5mm, and the preferred thickness may be 0.15mm.

[0077] In laser additive processing, the topmost thin sheet material may be an upper cladding layer. To detect a cold weld caused by insufficient fusion during additive processing, the preset thickness of the thin sheet material is 0.01 mm to 0.2 mm. Similarly, the preset thickness of the upper cladding layer of different materials is different.

[0078] Before introducing the scheme of the present application, the relevant names of the present application are explained.

[0079] The envelope of the infrared light signal is the envelope of the electric signal curve corresponding to the infrared light signal generated after the weld without a defective weld or a qualified weld is formed. The qualified weld here refers to a weld that is slightly different from a weld without a defective weld but is acceptable.

[0080] The infrared light signal baseline is the infrared light signal amplitude range generated after the weld without a defective weld or a qualified weld is formed. The qualified weld here refers to a weld that is slightly different from a weld without a defective weld but is acceptable.

[0081] The reference upper edge of the infrared light signal is the upper edge of the envelope of the infrared light signal. The reference upper edge of the infrared light signal includes a plurality of third points, or the reference upper edge of the infrared light signal is composed of a plurality of third points. The upper edge of the envelope can also be understood as the upper boundary of the amplitude range of the infrared light signal generated by a weld without a void or a qualified weld formed at the corresponding positions of a plurality of workpieces at a welding moment.

[0082] The reference lower edge of the infrared light signal is the lower edge of the envelope of the infrared light signal. The lower edge of the envelope can also be understood as the lower boundary of the infrared light signal amplitude range generated by a weld without a void or a qualified weld formed at the corresponding positions of multiple workpieces at a welding moment.

[0083] The reference center line of the infrared light signal is the center line of the reference upper edge line of the infrared light signal and the reference lower edge line of the infrared light signal. The reference center line of the infrared light signal includes a plurality of second points, or the reference center line of the infrared light signal is composed of a plurality of second points. Optionally, the reference center line of the infrared light signal can also be obtained by:

[0084] The amplitudes of multiple welds without defective joints or qualified welds at different delay times in multiple historical weldings are counted, the average amplitude values ​​corresponding to multiple same delay times are calculated, and the reference center line of the infrared light signal is obtained based on the obtained average amplitude values ​​corresponding to different delay times.

[0085] The average offset of the infrared light signal refers to the offset of the infrared light signal relative to the reference center line of the infrared light signal during the welding process. It can be understood that the electrical signal corresponding to the infrared light includes multiple first points, the reference center line includes multiple second points, and the multiple first points correspond to the multiple second points in time. The average offset of the infrared light signal is obtained according to the electrical signal corresponding to the infrared light signal and the reference center line of the infrared light signal, including: calculating the absolute value of the difference between the amplitude represented by each of the multiple first points and the amplitude represented by the second point corresponding to each first point; adding and averaging the absolute values ​​of the calculated multiple differences to obtain the average offset of the infrared light signal.

[0086] In laser processing applications, the infrared radiation signal corresponds to the infrared radiation signal with a wavelength in the range of 1250nm to 1700nm. The visible light radiation signal corresponds to the visible light radiation signal in the range of 400nm to 700nm. The laser processing reflection signal corresponds to the processing laser reflection signal during actual laser processing, such as the processing laser wavelength of 915nm, 1064nm, 1080nm, etc. The wavelength of the processing laser is related to the actual wavelength of the laser used. In some use environments, the suitable range of the infrared radiation signal can be extended outside the range of 1250nm to 1700nm. In some use environments, the visible light radiation signal can be extended outside the range of 400nm to 700nm.

[0087] The specific implementation method of the solution of this application is introduced in detail below.

[0088] See also Figure 2 , Figure 2 A schematic diagram of a welding cold joint detection method provided in an embodiment of the present application. Figure 2 As shown, the method includes:

[0089] S201. An industrial control computer obtains an electrical signal corresponding to an infrared light signal generated by a target weld in a first period of time.

[0090] The start time of the first time period is not earlier than the time when a complete target weld is formed. The target weld is formed by laser processing of a thin sheet material.

[0091] It should be pointed out that the complete target weld in the present application does not mean that the target weld has no cold welds, but refers to the weld formed after one processing.

[0092] like Figure 3a As shown, time t1 is the time when the welding defect detection (WDD) system starts working, t2 is the time when the WDD system stops working, t3 is the time when the laser starts to emit laser light, and t4 is the time when the laser stops emitting laser light. The target weld is formed on the workpiece (such as the upper plate 10 and the lower plate 11) when the laser works in the time period t3-t4. Time t5 is the time when the intensity of the infrared light radiated by the target weld begins to be less than the light intensity threshold, and the light intensity threshold can be 0. The time when the above-mentioned complete target weld is formed is time t4. Optionally, the first time period is included in the time period t4-t5.

[0093] It should be understood that laser processing is a continuous process. The laser light is also discontinuous, that is, the laser emits light for a period of time, and the laser does not emit light for the next period of time. The laser light emission and non-light emission are controlled by the signal in the laser light emission. Figure 3b As shown, weld 1, weld 2, weld 3 and weld 4 are produced by laser processing the thin film four times. Among them, the time period from time T1 to time T2 is the laser light emitting time period, weld 1 is produced in this time period, and the time when the complete weld 2 is formed is time T2. The time period from time T3 to time T4 is the laser light emitting time period, weld 2 is produced in this time period, and the time when the complete weld 2 is formed is time T4. The time period from time T5 to time T6 is the laser light emitting time period, weld 3 is produced in this time period, and the time when the complete weld 3 is formed is time T6. The time period from time T7 to time T8 is the laser light emitting time period, weld 4 is produced in this time period, and the time when the complete weld 4 is formed is time T8.

[0094] During the welding process, the infrared light signal radiated by the weld will be received by the multi-optical sensor module and converted into an electrical signal, which is then transmitted to the industrial control computer. Optionally, before transmitting the electrical signal to the industrial control computer, the multi-optical sensor module processes the electrical signal, including but not limited to methods, filtering, etc., before using the electrical signal to determine whether the weld has a cold weld. This can increase the amplitude of the electrical signal and reduce the noise in the electrical signal.

[0095] The optional industrial control computer can process the received electrical signal before using it to determine whether the weld has a cold weld, and the processing includes but is not limited to filtering, etc. The industrial control computer then uses the processed electrical signal to determine whether the weld has a cold weld.

[0096] S202, the industrial control computer determines whether there is a cold weld in the target weld according to the electrical signal corresponding to the infrared light signal.

[0097] In a possible implementation manner, the industrial computer determines whether there is a cold weld in the target weld according to the electrical signal corresponding to the optical signal, including:

[0098] The average offset of the infrared light signal is obtained based on the electrical signal corresponding to the infrared light signal and the reference center line of the infrared light signal; whether there is a cold weld in the target weld is determined based on the average offset of the infrared light signal; if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the average offset of the infrared light signal exceeds the preset offset range, it is determined that there is a cold weld in the target weld.

[0099] The reference center line of the infrared light signal is the center line of the reference upper edge line of the infrared light signal and the reference lower edge line of the infrared light signal. The center line of the reference upper edge line of the infrared light signal and the reference lower edge line of the infrared light signal is the envelope of the electrical signal corresponding to the infrared light signal generated by multiple welds without cold welds obtained in multiple historical laser processing processes after welding. The multiple welds without cold welds are produced by laser processing the same processing material using the same processing technology.

[0100] It should be understood that, since the electrical signal corresponding to the infrared light signal is composed of multiple points, the reference upper edge line and the reference lower edge line corresponding to the infrared light signal can also be regarded as composed of multiple points, wherein the first point on the reference upper edge line and the reference lower edge line corresponding to the infrared light signal can be regarded as collected at the moment when a complete weld is formed during multiple historical laser processing processes. The reference center line corresponding to the infrared light signal can also be regarded as composed of multiple points, wherein the amplitude corresponding to each point on the reference center line corresponding to the infrared light signal is the average value of the amplitudes corresponding to the two points corresponding in time on the reference upper edge line and the reference lower edge line corresponding to the infrared light signal.

[0101] In a possible implementation, the electrical signal corresponding to the infrared light includes a plurality of first points, the reference center line includes a plurality of second points, the plurality of first points correspond to the plurality of second points in time, and the industrial control computer obtains an average offset of the infrared light signal according to the electrical signal corresponding to the infrared light signal and the reference center line of the infrared light signal, including:

[0102] The industrial computer calculates the absolute value of the difference between the amplitude represented by each of the multiple first points and the amplitude represented by the second point corresponding to each first point in time; the absolute values ​​of the calculated multiple differences are added and then averaged to obtain the average offset of the infrared light signal.

[0103] In one example, if Figure 4a As shown, it is assumed that the electrical signal curve corresponding to the infrared light signal includes 8 first points, namely a1, a2, a3, a4, a5, a6, a7 and a8; the reference center line corresponding to the infrared light signal includes 8 second points, namely b1, b2, b3, b4, b5, b6, b7 and b8. Among them, the 8 first points correspond to the 8 second points one by one in time. The industrial control computer calculates the absolute value of the amplitude difference between the 8 first points and the 8 second points corresponding in time, and obtains 8 absolute values, and then sums and averages the 8 absolute values, and the result obtained is the average offset of the infrared light signal.

[0104] After obtaining the average offset of the infrared light signal, the industrial control computer determines whether the average offset of the infrared light signal exceeds the preset offset range. If it exceeds the preset offset range, the industrial control computer determines that there is a cold weld in the target weld; if it does not exceed the preset offset range, the industrial control computer determines that there is no cold weld in the target weld.

[0105] In another possible implementation, the electrical signal corresponding to the infrared light includes multiple first points, the reference center line includes multiple second points, and the multiple first points correspond to the multiple second points in time. The industrial control computer calculates the difference between the amplitude represented by each of the multiple first points and the amplitude represented by the second point corresponding to each first point in time; the industrial control computer obtains the difference greater than 0 from the obtained difference, sums and averages the difference greater than 0 to obtain the upper average offset of the infrared light signal. The industrial control computer determines whether the upper average offset of the infrared light signal exceeds the preset offset range; if it exceeds the preset offset range, the industrial control computer determines that there is a cold weld in the target weld; if it does not exceed the preset offset range, the industrial control computer determines that there is no cold weld in the target weld. It should be understood that the determination of whether the upper average offset of the infrared light signal exceeds the preset offset range specifically refers to whether the upper average offset of the infrared light signal is higher than the upper limit of the preset offset range. If it is higher, it is determined that there is a cold weld in the target weld.

[0106] Since the heat radiated by a weld with a cold weld after welding is higher than the energy radiated by a weld without a cold weld after welding, the above difference greater than 0 can better characterize the heat radiated by the weld after welding. Therefore, when judging whether there is a cold weld in the weld based on the difference greater than 0, a more accurate result can be obtained.

[0107] In another possible implementation, the electrical signal curve corresponding to the infrared light signal includes multiple first points, the reference center line includes multiple second points, and the multiple first points correspond to the multiple second points in time. The industrial control computer calculates the difference between the amplitude represented by each of the multiple first points and the amplitude represented by the second point corresponding to each first point in time; the industrial control computer obtains the difference less than 0 from the obtained difference, sums and averages the difference less than 0 to obtain the lower average offset of the infrared light signal. The industrial control computer determines whether the lower average offset of the infrared light signal exceeds the preset offset range; if it exceeds the preset offset range, the industrial control computer determines that there is a cold weld in the target weld; if it does not exceed the preset offset range, the industrial control computer determines that there is no cold weld in the target weld. It should be understood that the determination of whether the lower average offset of the infrared light signal exceeds the preset offset range specifically refers to whether the lower average offset of the infrared light signal is lower than the lower limit of the preset offset range; if it is lower, it is determined that there is a cold weld in the target weld.

[0108] In an optional embodiment, the preset offset range is [-μ-4σ, μ+4σ]; wherein μ and σ are the mean and standard deviation of the average offset of the electrical signal corresponding to the infrared light signal generated in the second time period by multiple complete welds without false welds obtained in the historical laser processing process; the starting time of the second time period is no earlier than the time when a complete weld without false welds is formed.

[0109] It should be understood that the moment when a complete weld is formed in the historical laser processing process refers to the moment when the laser stops working in a processing process, and the starting moment of the second time period is not earlier than the moment when the laser stops working. In other words, the industrial control computer obtains the electrical signals corresponding to the infrared light signals radiated by multiple welds without false welds formed in the historical laser processing process after welding, and then calculates the mean μ and standard deviation σ of the average offset of the electrical signals corresponding to the infrared light signals radiated by multiple welds without false welds after welding.

[0110] Optionally, the difference between the start time of the first time period and the time when the complete target weld is formed is greater than or equal to the difference between the start time of the second time period and the time when the complete weld is formed in the historical laser processing process.

[0111] It should be noted that the difference between the start time of the first time period and the time when the complete target weld is formed is set to be greater than the difference between the start time of the second time period and the time when the complete weld is formed in the historical laser processing process. The reason is that: after the complete weld is formed, the heat radiated by the weld gradually decreases; after the complete weld is formed, for two welds without cold welds, the heat radiated at the same time is the same or the difference between the two is small; for a weld with cold welds and a weld without cold welds, at the same time, the heat radiated by the weld with cold welds is higher than the heat radiated by the weld without cold welds; there may even be a situation where, after the complete weld is formed, the heat radiated by the weld with cold welds at the third moment is higher than the heat radiated by the weld without cold welds at the fourth moment, wherein the third moment is later than the fourth moment. In other words, for a weld A, if the heat radiated by weld A at the third moment is higher than the heat radiated by the weld without cold welds at the fourth moment, it means that weld A has cold welds.

[0112] Therefore, when detecting whether there is a cold weld in the target weld, the electrical signal corresponding to the infrared light signal generated by the target weld in the first time period is obtained, and the electrical signal corresponding to the infrared light signal generated in the first time period is compared with the expectation and variance of the electrical signal corresponding to the infrared light signal generated in the second time period based on multiple welds without cold welds formed in the historical laser processing process to determine whether there is a cold weld in the target weld, which can improve the accuracy of cold weld detection.

[0113] And because the heat radiated by the weld gradually decreases after a complete weld is formed, the amplitude of the electrical signal corresponding to the infrared light signal generated by the target weld in the first period is smaller than the amplitude of the electrical signal corresponding to the infrared light signal generated by the target weld before the first period. Therefore, for the industrial control computer, the processing amplitude value is smaller and the processing speed is relatively faster, thereby improving the efficiency of cold weld detection.

[0114] In a possible implementation, the industrial control computer can also determine whether there is a cold weld in the target weld based on the following method.

[0115] Method 1: The industrial control computer obtains the upper limit value of the infrared light signal based on the electrical signal curve of the infrared light signal and the upper reference line of the infrared light signal; the industrial control computer determines whether the target weld has a cold weld based on the upper limit value of the infrared light signal. If the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the upper reference line of the infrared light signal, and the upper limit value of the infrared light signal is higher than the upper limit threshold, the industrial control computer determines that the target weld has a cold weld.

[0116] The reference upper edge line of the infrared light signal is the upper edge line of the envelope line obtained by generating an electrical signal corresponding to the infrared light signal after a complete weld without voids is formed in a historical welding process.

[0117] In one example, the upper limit value of the infrared light signal is obtained as follows:

[0118] The electrical signal curve corresponding to the infrared light signal includes multiple first points, or the electrical signal curve corresponding to the infrared light signal is composed of multiple first points; the reference upper edge line of the infrared light signal includes multiple third points, or the reference upper edge line of the infrared light signal is composed of multiple third points; the multiple first points and the multiple third points correspond in time; the industrial control computer calculates the difference between the amplitude represented by each first point among the multiple first points and the amplitude represented by the third point corresponding to the first point; in this way, the industrial control computer obtains multiple differences and determines the maximum value of the multiple differences as the upper limit value of the infrared light signal.

[0119] In one example, the upper limit threshold is obtained as follows:

[0120] The reference center line of the infrared light signal includes a plurality of second points, or the reference center line of the infrared light signal is composed of a plurality of second points. The plurality of second points correspond to the plurality of third points in time. The industrial control computer calculates the difference between the amplitude represented by each of the plurality of third points and the amplitude represented by the second point corresponding to the third point in time; in this way, the industrial control computer obtains a plurality of differences, and determines the maximum value of the plurality of differences as the upper limit threshold of the infrared light signal.

[0121] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than that of infrared light generated by a weld without a cold weld. Accordingly, the upper limit value of the infrared light signal generated by a weld with a cold weld is higher than that of the infrared light signal generated by a weld without a cold weld. Therefore, after a complete target weld is formed, the upper limit value of the infrared light signal generated by the target weld is compared with the upper limit threshold to determine whether the energy of infrared light generated by the weld is higher than that of infrared light generated by a weld without a cold weld, thereby determining whether the target weld has a cold weld.

[0122] Method 2: The industrial control computer obtains the upper local area of ​​the infrared light signal based on the electric signal curve corresponding to the infrared light signal and the upper reference line of the infrared light signal, wherein the upper local area of ​​the infrared light is the area between the portion of the electric signal curve corresponding to the infrared light signal whose amplitude is greater than the amplitude of the upper reference line of the infrared light signal and the upper reference line of the infrared light signal. The industrial control computer determines whether there is a cold weld in the target weld based on the upper local area of ​​the infrared light signal. If the amplitude of the electric signal curve corresponding to the infrared light signal is higher than the amplitude of the upper reference line of the infrared light signal, and the upper local area of ​​the infrared light signal is greater than the upper local area threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0123] In one example, the upper local area of ​​the infrared light signal is obtained as follows:

[0124] Determine a first moment and a second moment, wherein the first moment is the starting moment of the first time period, and the second moment is the moment when the electrical signal curve corresponding to the infrared light signal intersects with the reference upper edge line of the infrared light signal. The electrical signal curve corresponding to the infrared light signal includes multiple first points, or the electrical signal curve corresponding to the infrared light signal is composed of multiple first points; the reference upper edge line of the infrared light signal includes multiple third points, or the reference upper edge line of the infrared light signal is composed of multiple third points; the multiple first points correspond to the multiple third points in time. The second moment is the moment when the amplitude represented by the first point is the same as the amplitude represented by the third point corresponding to the first point in time. The industrial control computer calculates the first integral area under the electrical signal curve corresponding to the infrared light signal between the first moment and the second moment, and calculates the second integral area under the reference upper edge line of the infrared light signal between the first moment and the second moment; the difference between the first integral area and the second integral area is determined as the upper local area of ​​the infrared light signal. Figure 4b shown.

[0125] In one example, the upper local area threshold is determined as follows:

[0126] The reference upper edge line of the infrared light signal includes a plurality of third points, or the reference upper edge line of the infrared light signal is composed of a plurality of third points; the reference center line of the infrared light signal includes a plurality of second points, or the reference center line of the infrared light signal is composed of a plurality of second points; the industrial control computer determines the starting third point and the ending third point; wherein the starting third point is the third point corresponding to the starting second point in time, the ending third point is the third point whose amplitude is the same as the amplitude represented by the second point corresponding in time, and the second point is the first second point in the reference center line of the infrared light signal. The industrial control computer calculates the third integral area under the portion between the starting third point and the ending third point in the reference upper edge line of the infrared light signal, and calculates the fourth integral area under the portion between the second point corresponding in time to the starting third point and the ending third point in time in the reference center line of the infrared light signal; the industrial control computer determines half of the difference between the third integral area and the fourth integral area as the upper local area threshold.

[0127] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than the energy of infrared light generated by a weld without a cold weld. Accordingly, the upper local area of ​​the infrared light signal generated by the weld with a cold weld is larger than the upper local area of ​​the infrared light signal generated by the weld without a cold weld. Therefore, after a complete target weld is formed, the upper local area of ​​the infrared light signal generated by the target weld is compared with the upper local area threshold to determine whether the energy of infrared light generated by the weld is higher than the energy of infrared light generated by the weld without a cold weld, thereby determining whether the target weld has a cold weld.

[0128] Method three: the industrial control computer determines the slope of the infrared light signal according to the electrical signal curve corresponding to the infrared light signal, and determines whether there is a cold weld in the target weld according to the slope of the infrared light signal; if the slope of the infrared light signal is greater than the slope threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0129] Furthermore, if the amplitude of the electric signal curve corresponding to the infrared light signal is higher than the reference upper edge amplitude of the infrared light signal, and the slope of the infrared light signal is greater than the slope threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0130] In one example, the slope of the infrared light signal is obtained as follows:

[0131] The industrial computer determines the first starting point and the first ending point from the electrical signal curve corresponding to the infrared light signal, wherein the amplitude represented by the first starting point is collected at the beginning of the second period, and the first ending point is the first point whose amplitude is 0; Figure 4c As shown; the industrial computer determines the acquisition time of the first starting point and the acquisition time of the first ending point; the industrial computer calculates the first difference between the amplitude represented by the first starting point and the amplitude represented by the first ending point, calculates the second difference between the acquisition time of the first starting point and the acquisition time of the first ending point, and calculates the ratio of the first difference to the second difference, which is the slope of the infrared light signal.

[0132] It should be understood that an amplitude of 0 indicates that the difference between the temperature of the target weld and the working environment temperature is less than a preset temperature value. For example, an amplitude of 0 indicates that the temperature of the target weld is the same as the working environment temperature.

[0133] In one example, the slope threshold is obtained as follows:

[0134] The industrial control computer determines a second starting point and a second ending point from a reference center line of the infrared light signal; wherein the second starting point is a second point in the reference center line of the infrared light signal corresponding to the first starting point in time, and the second ending point is a second point in the reference center line of the infrared light signal corresponding to the first ending point in time; the industrial control computer calculates a third difference between the amplitude represented by the second starting point and the amplitude represented by the second ending point; the industrial control computer calculates a ratio of the third difference to the second difference, and determines twice the absolute value of the ratio as a slope threshold.

[0135] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than that of infrared light generated by a weld without a cold weld. Accordingly, the absolute value of the slope of the infrared light signal generated by the weld with a cold weld is greater than the absolute value of the slope of the infrared light signal generated by the weld without a cold weld. Therefore, after a complete target weld is formed, the absolute value of the slope of the infrared light signal generated by the target weld is compared with the slope threshold to determine whether the energy of infrared light generated by the weld is higher than that of infrared light generated by the weld without a cold weld, thereby determining whether the target weld has a cold weld.

[0136] Method 4: The industrial control computer obtains the average value of the amplitude of the infrared light signal according to the electrical signal curve corresponding to the infrared light signal, and determines whether there is a cold weld in the target weld according to the average value of the amplitude of the infrared light signal; if the average value of the amplitude of the infrared light signal is higher than the mean threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0137] Furthermore, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the reference upper edge amplitude of the infrared light signal, and the average value of the amplitude of the infrared light signal is higher than the mean threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0138] In one example, the mean threshold is determined as follows:

[0139] The industrial control computer calculates an average value of amplitudes represented by a plurality of second points included in the reference center line of the infrared light signal, and determines twice the average value as the mean threshold.

[0140] After a complete weld is formed, the energy of infrared light generated by a weld with a cold weld is higher than that of infrared light generated by a weld without a cold weld. Accordingly, the average value of the amplitude of the infrared light signal generated by the weld with a cold weld is greater than that of the infrared light signal generated by the weld without a cold weld. Therefore, after a complete target weld is formed, the average value of the amplitude of the infrared light signal generated by the target weld is compared with the mean threshold to determine whether the energy of infrared light generated by the weld is higher than that of infrared light generated by the weld without a cold weld, thereby determining whether the target weld has a cold weld.

[0141] In a possible implementation, the method of this embodiment further includes:

[0142] The industrial control computer displays the electrical signal curve corresponding to the infrared light signal generated by the target weld after the target weld is formed completely; and displays the result of whether there is a cold weld in the target weld.

[0143] Figure 4d A schematic diagram of a detection result provided in an embodiment of the present application. Figure 4dAs shown, the industrial computer displays the electrical signal corresponding to the infrared light signal generated by the target weld after welding and the reference center line of the infrared light signal, and shows whether there is a virtual weld in the target weld.

[0144] By displaying the electrical signal curve corresponding to the infrared light signal generated by the target weld after welding and the result of whether the target weld has a cold weld, the processing personnel can observe the laser processing results in real time, that is, whether the weld after laser processing has a cold weld.

[0145] S203. When it is determined that a target weld has a cold weld, the industrial control computer obtains position information of the target weld.

[0146] The position information of the target weld can be identified by the serial number of the target weld. It should be understood that since laser processing is a continuous process, the obtained weld is also continuous, so the position of the weld can be indicated by the serial number of the weld.

[0147] After obtaining the position information of the target weld, the industrial control computer transmits the position information of the target weld to the laser welding system, so that the laser welding system reprocesses the target weld according to the position information of the target weld to achieve the purpose of eliminating false welds.

[0148] In a feasible implementation, when it is determined that the target weld has a cold weld, the industrial computer obtains the distance between the laser processing head and the processing material (i.e., the upper plate 10) when the target weld is processed from the laser welding system. This distance can be called the processing distance. The processing distance is compared with the preset distance. If the processing distance is different from the preset distance, it indicates that the reason for the cold weld in the target weld may be that the processing distance changes, resulting in a change in the defocus amount, which leads to the occurrence of a cold weld. The industrial computer sends an instruction message to the laser welding system to instruct the laser welding system to adjust the distance between the laser processing head and the sheet, and the adjusted distance is the same as the preset distance. The preset distance is a manually set distance between the laser processing head and the processing material so that there is no cold weld in the weld produced by processing.

[0149] Optionally, if the processing distance is the same as the preset distance, it means that the cause of the cold solder joint is not caused by the defocus amount. The industrial control computer obtains the temperature of the lens in the laser processing head during processing. It should be understood that when the lens is contaminated, the temperature of the lens will increase, so it is determined whether the lens is contaminated by determining whether the temperature of the lens is higher than the temperature of the lens when it is not contaminated. When it is determined that the temperature of the lens is higher than the temperature of the lens when it is not contaminated, the industrial control computer sends an alarm message to the processing personnel to provide the processing personnel with information that the lens in the laser processing head is contaminated.

[0150] Optionally, if the processing distance is the same as the preset distance, it means that the cause of the cold weld is not caused by the defocus amount. The industrial control computer sends instruction information to the laser welding system to instruct the laser welding system to increase the power of the laser.

[0151] After completing the above adjustments, the industrial control computer transmits the position information of the target weld to the laser welding system, so that the laser welding system reprocesses the target weld according to the position information of the target weld to achieve the purpose of eliminating false welds.

[0152] It can be seen that in the solution of the present application, during the laser processing, the infrared light signal generated by the weld after welding is obtained by the multi-optical sensor module, and then the infrared light signal is used to determine whether the weld has a cold weld. Compared with the prior art, the solution of the present application has the characteristics of non-contact and real-time, and can be fully inspected in industrial production. And the solution of the present application can detect defects such as cold welds. After obtaining the position information of the target weld, the position information of the target weld is transmitted to the laser welding system, so that the laser welding system reprocesses the target weld to achieve the purpose of automatic repair welding.

[0153] See also Figure 5 , Figure 5 This is a schematic diagram of the structure of an industrial control computer provided in an embodiment of the present application. Figure 5 As shown, the industrial computer 500 includes:

[0154] An acquisition unit 501 is used to acquire an electrical signal corresponding to an infrared light signal generated by a target weld in a first period, wherein a start time of the first period is no earlier than a time when a complete target weld is formed; the target weld is formed by laser processing of a thin sheet material;

[0155] The determination unit 502 is used to determine whether there is a cold weld in the target weld according to the electrical signal corresponding to the infrared light signal.

[0156] In a possible implementation, the determination unit 502 is specifically used to determine whether a target weld has a cold weld using an electrical signal curve corresponding to the infrared light signal.

[0157] In a possible implementation, the determination unit 502 is specifically used for:

[0158] The average offset of the infrared light signal is obtained according to the electrical signal curve corresponding to the infrared light signal and the reference center line of the infrared light signal; whether there is a cold weld in the target weld is determined according to the average offset of the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the average offset of the infrared light signal exceeds the preset offset range, it is determined that there is a cold weld in the target weld.

[0159] In a possible implementation, the electric signal curve corresponding to the infrared light includes a plurality of first points, the reference center line includes a plurality of second points, the plurality of first points correspond to the plurality of second points, and in terms of obtaining an average offset of the infrared light signal according to the electric signal corresponding to the infrared light signal and the reference center line of the infrared light signal, the determination unit 502 is specifically used to:

[0160] The absolute value of the difference between the amplitude represented by each first point among the multiple first points and the amplitude represented by the second point corresponding to each first point is calculated; the absolute values ​​of the calculated multiple differences are added and then averaged to obtain the average offset of the infrared light signal.

[0161] In one possible implementation, the preset offset range is [-μ-4σ, μ+4σ]; wherein μ and σ are the mean and standard deviation of the average offset of the electrical signal corresponding to the infrared light signal generated in the second time period by multiple complete welds without false welds obtained in the historical laser processing process; the starting time of the second time period is no earlier than the time when a complete weld without false welds is formed.

[0162] In a possible implementation, the determining unit 502 is specifically configured to:

[0163] An upper limit value of the infrared light signal is obtained according to the electrical signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal; whether a target weld has a cold weld is determined according to the upper limit value of the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the upper limit value of the infrared light signal is higher than the upper limit threshold, it is determined that a cold weld exists in the target weld.

[0164] In a possible implementation, the electric signal curve corresponding to the infrared light signal includes a plurality of first points, the reference upper edge line includes a plurality of third points, the plurality of first points correspond to the plurality of third points in time, and in the aspect that the industrial control computer obtains the upper limit value of the infrared light signal according to the electric signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, the determination unit is specifically used for:

[0165] The difference between the amplitude represented by each of the plurality of first points and the amplitude represented by the third point corresponding to the first point in time is calculated to obtain a plurality of difference values; the maximum value among the plurality of difference values ​​is determined as the upper limit value of the infrared light signal.

[0166] In a possible implementation, the reference center line of the infrared light signal includes a plurality of second points, the reference upper edge line includes a plurality of third points, the plurality of second points correspond to the plurality of third points in time, and the determining unit 502 is further configured to:

[0167] The difference between the amplitude represented by each of the plurality of third points and the amplitude represented by the second point corresponding to the third point in time is calculated to obtain a plurality of difference values; and the maximum value of the plurality of difference values ​​is determined as the upper limit threshold.

[0168] In a possible implementation, the determining unit is specifically configured to:

[0169] An upper local area of ​​the infrared light signal is obtained according to an electrical signal curve corresponding to the infrared light signal and a reference upper edge line of the infrared light signal, wherein the upper local area of ​​the infrared light signal is the area between a portion of the electrical signal curve corresponding to the infrared light signal having an amplitude greater than the amplitude of the reference upper edge line and the reference upper edge line; whether a target weld has a cold weld is determined according to the upper local area of ​​the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the upper local area of ​​the infrared light signal is greater than an upper local area threshold, it is determined that a cold weld exists in the target weld.

[0170] In a possible implementation, in the aspect that the industrial computer obtains the upper local area of ​​the infrared light signal according to the electrical signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, the determination unit 502 is specifically used to:

[0171] Determine a first moment and a second moment, wherein the first moment is the starting moment of the first time period, and the second moment is the moment when the electrical signal curve corresponding to the infrared light signal intersects with the reference upper edge line; calculate a first integral area under the electrical signal curve corresponding to the infrared light signal between the first moment and the second moment; and calculate a second integral area under the reference upper edge line between the first moment and the second moment; and determine the difference between the first integral area and the second integral area as the upper local area of ​​the infrared light signal.

[0172] In a possible implementation, the reference upper edge line of the infrared light signal includes a plurality of third points, the reference midline of the infrared light signal includes a plurality of second points, the plurality of third points correspond to the plurality of second points in time, and the determining unit 502 is further configured to:

[0173] Determine a starting third point and an ending third point from the reference upper edge line of the infrared light signal; wherein the starting third point is the third point corresponding to the starting second point, the ending third point is the third point representing an amplitude identical to the amplitude represented by the corresponding second point, and the starting second point is the first second point in the reference center line of the infrared light signal; calculate a third integral area under the portion between the starting third point and the ending third point in the reference upper edge line of the infrared light signal, and calculate a fourth integral area under the portion between the second point corresponding in time to the starting third point and the second point corresponding in time to the ending third point in the reference center line of the infrared light signal; determine half of the difference between the third integral area and the fourth integral area as an upper local area threshold.

[0174] In a possible implementation, the determining unit is specifically configured to:

[0175] The slope of the infrared light signal is determined according to the electrical signal curve corresponding to the infrared light signal; and whether there is a cold weld in the target weld is determined according to the slope of the infrared light signal; wherein, if the slope of the infrared light signal is greater than the slope threshold, it is determined that there is a cold weld in the target weld.

[0176] Optionally, the electrical signal curve corresponding to the infrared light signal includes a plurality of first points. In determining the slope of the infrared light signal according to the electrical signal curve corresponding to the infrared light signal, the determining unit 502 is specifically configured to:

[0177] Determine a starting first point and an ending first point from a plurality of first points, wherein the amplitude represented by the starting first point is collected at the starting moment of the second time period, and the ending first point is the first point represented by an amplitude of 0; determine the collection time of the starting first point and the collection time of the ending first point; calculate a first difference between the amplitude represented by the starting first point and the amplitude represented by the ending first point, calculate a second difference between the collection time of the starting first point and the collection time of the ending first point, calculate a ratio of the first difference to the second difference, and determine the ratio as the slope of the infrared light signal.

[0178] Optionally, the reference center line of the infrared light signal includes a plurality of second points, the plurality of first points correspond to the plurality of second points in time, and the determining unit 502 is further configured to:

[0179] Determine a starting second point and an ending second point from a plurality of second points; wherein the starting second point is a second point in the reference center line of the infrared light signal corresponding to the starting first point in time, and the ending second point is a second point in the reference center line of the infrared light signal corresponding to the ending first point in time; the industrial control computer calculates a third difference between the amplitude represented by the starting second point and the amplitude represented by the ending second point; calculates a ratio between the third difference and the second difference, and determines twice the absolute value of the ratio as a slope threshold.

[0180] In combination with the first aspect, in a possible implementation manner, the electrical signal curve corresponding to the infrared light signal includes a plurality of first points, and the determining unit 502 is specifically configured to:

[0181] The industrial control computer calculates an average value of the amplitude of the infrared light signal based on multiple first points, wherein the average value of the amplitude of the infrared light signal is the average value of the amplitudes represented by the multiple first points; the industrial control computer determines whether there is a cold weld in the target weld based on the average value of the amplitude of the infrared light signal; if the average value of the amplitude of the infrared light signal is higher than the mean threshold, the industrial control computer determines that there is a cold weld in the target weld.

[0182] Optionally, the reference center line of the infrared light signal includes multiple second points, and the mean threshold is twice the average value of the amplitudes represented by the multiple second points.

[0183] In a possible implementation, the acquisition unit 501 is further configured to acquire the position information of the target weld if it is determined that the target weld has a cold weld;

[0184] Industrial Computer 500 also includes:

[0185] The transceiver unit 503 is used to transmit the position information of the target weld to the laser welding system, so that the laser welding system re-processes the target weld based on the position information of the target weld.

[0186] In a possible implementation, the industrial computer 500 further includes:

[0187] The display unit 504 is used to display the electric signal curve corresponding to the infrared light signal generated by the target weld after the target weld is completely formed; and to display the result of whether there is a cold weld in the target weld.

[0188] It should be noted that the above-mentioned units (acquisition unit 501, determination unit 502, transceiver unit 503 and display unit 504) are used to execute the relevant steps of the above-mentioned method. For example, acquisition unit 501 is used to execute the relevant content of S201, determination unit 502 is used to execute the relevant content of S202, and transceiver unit 503 and display unit 504 are used to execute the relevant content of S203. Each unit or module in the industrial computer 500 can be separately or completely combined into one or several other units or modules to constitute, or one (some) of the units or modules can be further divided into multiple smaller units or modules to constitute, which can achieve the same operation without affecting the realization of the technical effects of the embodiments of the present invention. The above-mentioned units or modules are divided based on logical functions. In practical applications, the functions of one unit (or module) can also be implemented by multiple units (or modules), or the functions of multiple units (or modules) can be implemented by one unit (or module).

[0189] Based on the description of the above method embodiment and device embodiment, please refer to Figure 6 , an embodiment of the present invention also provides a structural schematic diagram of another industrial control computer 600. Figure 6 The industrial computer 600 shown (the industrial computer 600 may be a computer device) includes a memory 601, a processor 602, a communication interface 603 and a bus 604. The memory 601, the processor 602 and the communication interface 603 are connected to each other through the bus 604.

[0190] The memory 601 may be a read-only memory (ROM), a static storage device, a dynamic storage device or a random access memory (RAM).

[0191] The memory 601 can store programs. When the program stored in the memory 601 is executed by the processor 602, the processor 602 and the communication interface 603 are used to execute the various steps of the welding cold joint detection method of the embodiment of the present application.

[0192] The processor 602 can adopt a general central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), a graphics processing unit (GPU) or one or more integrated circuits to execute relevant programs to implement the functions required to be performed by the units in the industrial control computer 600 of the embodiment of the present application, or to execute the welding cold solder joint detection method of the method embodiment of the present application.

[0193] The processor 602 may also be an integrated circuit chip with signal processing capability. In the implementation process, each step of the welding cold solder joint detection method of the present application may be completed by the hardware integrated logic circuit or software instructions in the processor 602. The above-mentioned processor 602 may also be a general-purpose processor, a digital signal processor (Digital Signal Processing, DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The disclosed methods, steps and logic block diagrams in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The steps of the method disclosed in the embodiments of the present application may be directly embodied as being executed by a hardware decoding processor, or may be executed by a combination of hardware and software modules in a decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 601, and the processor 602 reads the information in the memory 601, and combines its hardware to complete the functions required to be executed by the units included in the industrial control computer 500 of the embodiment of the present application, or executes the welding cold solder joint detection method of the method embodiment of the present application.

[0194] The communication interface 603 uses a transceiver such as, but not limited to, a transceiver to implement communication between the industrial computer 600 and other devices or a communication network. For example, data can be obtained through the communication interface 603 .

[0195] The bus 604 may include a path for transmitting information between various components of the industrial computer 600 (eg, the memory 601 , the processor 602 , and the communication interface 603 ).

[0196] It should be noted that although Figure 6 The industrial computer 600 shown only shows a memory, a processor, and a communication interface. However, in the specific implementation process, those skilled in the art should understand that the industrial computer 600 also includes other devices necessary for normal operation. At the same time, according to specific needs, those skilled in the art should understand that the industrial computer 600 may also include hardware devices for implementing other additional functions. In addition, those skilled in the art should understand that the industrial computer 600 may also only include the devices necessary for implementing the embodiments of the present application, and does not necessarily include Figure 6 All devices shown in .

[0197] The embodiment of the present application further provides a chip, which includes a processor and a data interface. The processor reads instructions stored in a memory through the data interface to implement the welding cold joint detection method.

[0198] Optionally, as an implementation method, the chip may further include a memory, in which instructions are stored, and the processor is used to execute the instructions stored in the memory. When the instructions are executed, the processor is used to execute the welding cold joint detection method.

[0199] An embodiment of the present application also provides a computer-readable storage medium, which stores instructions. When the computer-readable storage medium is executed on a computer or a processor, the computer or the processor executes one or more steps in any of the above methods.

[0200] The embodiment of the present application further provides a computer program product including instructions. When the computer program product is executed on a computer or a processor, the computer or the processor executes one or more steps in any of the above methods.

[0201] Those skilled in the art will appreciate that the functions described in conjunction with the various illustrative logic blocks, modules, and algorithm steps disclosed herein can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions described in the various illustrative logic blocks, modules, and steps can be stored or transmitted as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. Computer-readable media may include computer-readable storage media, which corresponds to tangible media, such as data storage media, or includes any media (e.g., based on a communication protocol) that facilitates the transfer of a computer program from one place to another. In this manner, computer-readable media may generally correspond to (1) non-temporary tangible computer-readable storage media, or (2) communication media, such as signals or carrier waves. Data storage media may be any available media that can be accessed by one or more computers or one or more processors to retrieve instructions, codes, and / or data structures for implementing the techniques described in this application. A computer program product may include computer-readable media.

[0202] As an example and not limitation, such computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage, flash memory, or any other medium that can be used to store the desired program code in the form of instructions or data structures and can be accessed by a computer. Also, any connection is properly referred to as a computer-readable medium. For example, if instructions are transmitted from a website, server or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio and microwave are included in the definition of media. However, it should be understood that the computer-readable storage media and data storage media do not include connections, carrier waves, signals or other temporary media, but are actually directed to non-temporary tangible storage media. As used herein, disks and optical disks include compact disks (CDs), laser optical disks, optical optical disks, digital versatile disks (DVDs), and Blu-ray disks, where disks typically reproduce data magnetically, while optical disks reproduce data optically using lasers. Combinations of the above should also be included within the scope of computer-readable media.

[0203] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the term "processor" as used herein may refer to any of the aforementioned structures or any other structures suitable for implementing the techniques described herein. Additionally, in some aspects, the functions described by the various illustrative logic blocks, modules, and steps described herein may be provided within dedicated hardware and / or software modules configured for encoding and decoding, or incorporated in a combined codec. Moreover, the techniques may be fully implemented in one or more circuits or logic elements.

[0204] The techniques of the present application may be implemented in a variety of devices or apparatuses, including a wireless handset, an integrated circuit (IC), or a set of ICs (e.g., a chipset). Various components, modules, or units are described in this application to emphasize functional aspects of devices for performing the disclosed techniques, but do not necessarily need to be implemented by different hardware units. In fact, as described above, the various units may be combined in an encoded hardware unit in conjunction with appropriate software and / or firmware, or provided by interoperating hardware units (including one or more processors as described above).

[0205] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the specific descriptions of the corresponding steps in the aforementioned method embodiments, and will not be repeated here.

[0206] It should be understood that in the description of the present application, unless otherwise specified, " / " indicates that the objects associated before and after are in an "or" relationship, for example, A / B can represent A or B; wherein A and B can be singular or plural. Also, in the description of the present application, unless otherwise specified, "multiple" refers to two or more than two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, wherein a, b, c can be single or multiple. In addition, in order to facilitate the clear description of the technical solutions of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. are used to distinguish the same items or similar items with substantially the same functions and effects. Those skilled in the art can understand that the words "first", "second", etc. do not limit the quantity and execution order, and the words "first", "second", etc. do not limit them to be necessarily different. Meanwhile, in the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete manner for ease of understanding.

[0207] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the division of the unit is only a logical function division, and there may be other division methods in actual implementation, for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. The mutual coupling, direct coupling, or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0208] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0209] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium or transmitted through the computer-readable storage medium. The computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (digital subscriber line, DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media integrations. The available medium may be a read-only memory (ROM), or a random access memory (RAM), or a magnetic medium, such as a floppy disk, a hard disk, a tape, a disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid state disk (SSD), etc.

[0210] The above is only a specific implementation of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto, and any changes or replacements within the technical scope disclosed in the embodiment of the present application should be included in the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be based on the protection scope of the claims.

[0211] The device embodiments described above are merely illustrative, wherein the units and modules described as separate components may or may not be physically separated. In addition, some or all of the units and modules may be selected according to actual needs to achieve the purpose of the present embodiment. Those of ordinary skill in the art may understand and implement the present invention without creative effort.

[0212] The above is only a specific implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for detecting a cold weld, characterized in that: The method comprises: When laser processing is performed on a thin sheet material, an infrared light signal radiated by a target weld during and after the laser welding process is completed is received, wherein the infrared light signal is radiated after the processing laser acts on the thin sheet material, and the infrared light signal is received in a coaxial direction with the light output path of the processing laser; Acquire an electrical signal corresponding to an infrared light signal generated by a target weld in a first time period, wherein a start time of the first time period is no earlier than a time when the target weld is completely formed; the target weld is formed by laser processing a thin sheet material; Determine whether the target weld has a cold weld based on the electrical signal corresponding to the infrared light signal.

2. The method according to claim 1, characterized in that The step of determining whether the target weld has a cold weld according to the electrical signal corresponding to the infrared light signal comprises: Determine whether the target weld has a cold weld based on the electrical signal curve corresponding to the infrared light signal.

3. The method according to claim 2, characterized in that The step of determining whether the target weld has a cold weld according to the electrical signal curve corresponding to the infrared light signal comprises: Obtaining an upper limit value of the infrared light signal according to an electrical signal curve corresponding to the infrared light signal and a reference upper edge line of the infrared light signal; Determine whether the target weld has a cold weld based on the upper limit value of the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the reference upper edge amplitude of the infrared light signal, and the upper limit value of the infrared light signal is higher than the upper limit threshold, then it is determined that the target weld has a cold weld.

4. The method according to claim 3, characterized in that: The electric signal curve corresponding to the infrared light signal includes a plurality of first points, the reference upper edge line includes a plurality of third points, the plurality of first points correspond to the plurality of third points in time, and the upper limit value of the infrared light signal is obtained according to the electric signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, including: Calculating the difference between the amplitude represented by each of the plurality of first points and the amplitude represented by a third point corresponding to the first point in time, to obtain a plurality of difference values; The maximum value among the plurality of difference values ​​is determined as the upper limit value of the infrared light signal.

5. The method according to claim 3 or 4, characterized in that: The reference center line of the infrared light signal includes a plurality of second points, the reference upper edge line includes a plurality of third points, the plurality of second points correspond to the plurality of third points in time, and the method further includes: Calculating the difference between the amplitude represented by each of the plurality of third points and the amplitude represented by the second point corresponding to the third point in time, so as to obtain a plurality of difference values; A maximum value among the plurality of difference values ​​is determined as the upper limit threshold.

6. The method according to claim 2, characterized in that The step of determining whether the target weld has a cold weld according to the electrical signal curve corresponding to the infrared light signal comprises: The upper local area of ​​the infrared light signal is obtained according to the electric signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal, wherein the upper local area of ​​the infrared light signal is the area between the portion of the electric signal curve corresponding to the infrared light signal whose amplitude is greater than the amplitude of the reference upper edge line and the reference upper edge line; Determine whether the target weld has a cold weld based on the upper local area of ​​the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the upper local area of ​​the infrared light signal is greater than the upper local area threshold, then it is determined that the target weld has a cold weld.

7. The method according to claim 6, characterized in that The obtaining the upper local area of ​​the infrared light signal according to the electric signal curve corresponding to the infrared light signal and the reference upper edge line of the infrared light signal comprises: Determine a first moment and a second moment, wherein the first moment is the starting moment of the first time period, and the second moment is the moment when the electric signal curve corresponding to the infrared light signal intersects the reference upper edge line; Calculate a first integral area under the electric signal curve corresponding to the infrared light signal between the first moment and the second moment; and calculate a second integral area under the reference upper line between the first moment and the second moment; A difference between the first integrated area and the second integrated area is determined as an upper local area of ​​the infrared light signal.

8. The method according to claim 6 or 7, characterized in that: The reference upper edge line of the infrared light signal includes a plurality of third points, the reference midline of the infrared light signal includes a plurality of second points, the plurality of third points correspond to the plurality of second points in time, and the method further includes: Determine a starting third point and an ending third point from the reference upper edge line of the infrared light signal; wherein the starting third point is a third point corresponding to the starting second point, and the ending third point is a third point whose amplitude is the same as the amplitude represented by the second point corresponding in time; the starting second point is the first second point in the reference midline of the infrared light signal; Calculate a third integral area under the portion between the starting third point and the ending third point in the reference upper edge line of the infrared light signal, and calculate a fourth integral area under the portion between the second point corresponding in time to the starting third point and the second point corresponding in time to the ending third point in the reference center line of the infrared light signal; A half of a difference between the third integrated area and the fourth integrated area is determined as an upper local area threshold.

9. The method according to claim 2, characterized in that: The step of determining whether the target weld has a cold weld according to the electrical signal curve corresponding to the infrared light signal comprises: Determining the slope of the infrared light signal according to the electrical signal curve corresponding to the infrared light signal; Determine whether a target weld has a cold weld according to the slope of the infrared light signal; if the slope of the infrared light signal is greater than a slope threshold, determine that the target weld has a cold weld.

10. The method according to claim 9, characterized in that The electric signal curve corresponding to the infrared light signal includes a plurality of first points, and determining the slope of the infrared light signal according to the electric signal curve corresponding to the infrared light signal includes: Determine a starting first point and an ending first point from the multiple first points, wherein the amplitude represented by the starting first point is collected at the starting time, and the ending first point is the first point whose amplitude is 0; Determine the acquisition time of the first starting point and the acquisition time of the first ending point; Calculate the first difference between the amplitude represented by the first starting point and the amplitude represented by the first ending point, calculate the second difference between the acquisition time of the first starting point and the acquisition time of the first ending point, and calculate the ratio of the first difference to the second difference, which is the slope of the infrared light signal.

11. The method according to claim 9 or 10, characterized in that: The reference center line of the infrared light signal includes a plurality of second points, the plurality of first points correspond to the plurality of second points in time, and the method further includes: Determine a starting second point and an ending second point from the plurality of second points; wherein the starting second point is a second point in the reference center line of the infrared light signal corresponding to the starting first point in time, and the ending second point is a second point in the reference center line of the infrared light signal corresponding to the ending first point in time; Calculate a third difference between the amplitude represented by the second starting point and the amplitude represented by the second ending point; the industrial control computer calculates the ratio between the third difference and the second difference, and determines twice the absolute value of the ratio as the slope threshold.

12. The method according to claim 2, characterized in that: The electric signal curve corresponding to the infrared light signal includes a plurality of first points, and determining whether the target weld has a cold weld according to the electric signal curve corresponding to the infrared light signal includes: Calculating an average value of the amplitude of the infrared light signal according to the plurality of first points, wherein the average value of the amplitude of the infrared light signal is an average value of the amplitudes represented by the plurality of first points; Whether there is a cold weld in the target weld is determined according to the average value of the amplitude of the infrared light signal; if the average value of the amplitude of the infrared light signal is higher than the mean threshold, the industrial control computer determines that there is a cold weld in the target weld.

13. The method according to claim 12, characterized in that The reference center line of the infrared light signal includes a plurality of second points, and the method further includes: An average value of the amplitudes represented by the plurality of second points is calculated, and twice the average value is determined as a mean threshold value.

14. The method according to claim 2, characterized in that Determining whether the target weld has a cold weld according to the electrical signal curve corresponding to the infrared light signal includes: Obtaining an average offset of the infrared light signal according to an electrical signal curve corresponding to the infrared light signal and a reference midline of the infrared light signal; Whether there is a cold weld in the target weld is determined based on the average offset of the infrared light signal; wherein, if the amplitude of the electrical signal curve corresponding to the infrared light signal is higher than the amplitude of the reference upper edge line of the infrared light signal, and the average offset of the infrared light signal exceeds the preset offset range, it is determined that there is a cold weld in the target weld.

15. The method according to claim 14, characterized in that The electric signal curve corresponding to the infrared light includes a plurality of first points, the reference center line includes a plurality of second points, the plurality of first points correspond to the plurality of second points in time, and the average offset of the infrared light signal is obtained according to the electric signal curve corresponding to the infrared light signal and the reference center line of the infrared light signal, including: Calculate the absolute value of the difference between the amplitude represented by each of the plurality of first points and the amplitude represented by a second point corresponding to each of the first points in time; The absolute values ​​of the calculated multiple differences are added and then averaged to obtain an average offset of the infrared light signal.

16. The method according to claim 14 or 15, characterized in that The preset offset range is [-μ-4σ, μ+4σ]; wherein μ and σ are the mean and standard deviation of the average offset of the electrical signal corresponding to the infrared light signal generated in the second time period by multiple complete welds without false welds obtained in the historical laser processing process; the starting time of the second time period is no earlier than the time when the complete weld without false welds is formed.

17. The method according to any one of claims 1 to 16, characterized in that: The method further comprises: If it is determined that the target weld has a cold weld, obtaining position information of the target weld; The position information of the target weld is transmitted to the laser welding system, so that the laser welding system re-processes the target weld based on the position information of the target weld.

18. The method according to any one of claims 1 to 17, characterized in that: The method further comprises: After the target weld is completely formed, an electric signal curve corresponding to the infrared light signal generated by the target weld is displayed; and the result of whether the target weld has a cold weld is displayed.

19. The method according to any one of claims 1 to 18, characterized in that: The thickness of the sheet material is between 0.01 mm and 0.6 mm.

20. An industrial computer, characterized in that: include: An acquisition unit is used to receive an infrared light signal radiated by a target weld during and after laser welding when laser processing is performed on a sheet material, wherein the infrared light signal is radiated after the processing laser acts on the sheet material, and the infrared light signal is received in a coaxial direction of an output light path of the processing laser; an electrical signal corresponding to the infrared light signal generated by the target weld in a first time period is acquired, wherein a starting time of the first time period is no earlier than a time when the target weld is completely formed; and the target weld is formed by laser processing the sheet material; A display unit, used to display an electrical signal corresponding to the infrared light signal generated by the target weld in the first time period; The determination unit is used to determine whether there is a cold weld in the target weld according to the electrical signal corresponding to the infrared light signal.

21. An industrial computer, characterized in that: It includes a processor, the processor is connected to a memory, the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the industrial computer executes the method as described in any one of claims 1-19.

22. A laser processing control system, comprising: A laser welding system, a multi-optical sensor module, a signal processing module and an industrial control computer, wherein the industrial control computer is used to execute the method as described in any one of claims 1-19.

23. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and the computer program is executed by a processor to implement the method according to any one of claims 1 to 19.

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