JP2017217668A - Method for inspection of weldment state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for inspection of a weldment state by which decrease in accuracy of quality determination concerning a weldment state can be suppressed.SOLUTION: An inspection method for a weldment state of a weld zone 3 in which a bus bar 10 having a plating layer 10b on a copper plate 10a as a metal matrix and a reed 20 having a plating layer 20b on a copper wire 20a as a metal matrix are resistance-welded includes: a first process in which the resistance-welded bus bar 10 and reed 20 are ripped off from weld portions 11, 21 (weld zone 3) therebetween; a second process in which with respect to the buss bar 10 after the first process, a curve of a surface is detected as a surface state of a welding mark which remains in the buss bar 10 after the reed 20 at the buss bar side weld portion 11 is ripped off in the first process; and a third process in which a quality of the weldment state of the resistance-welded portions of the buss bar 10 and the reed 20 before the first process is determined.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a welding state inspection method.

  When welding metal parts plated for the purpose of suppressing corrosion due to oxidation, for example, resistance welding as described in Patent Document 1 is used. Patent Document 1 discloses a method of welding copper metal parts such as brass by micro resistance welding which is a kind of resistance welding. When welding metal parts plated using this type of resistance welding, the metal parts are joined together by melting the plating layer and melting and bonding the metals underneath.

JP-A-9-314353

  To determine whether the welded metal parts are joined, that is, whether the welded state is good or bad, after fixing the welded metal parts with a special resin, cut the welded portion, polish the cross section, and use an electron microscope, etc. In general, an inspection method for observation is used. In this general inspection method of the welding state, the quality of the welding state is determined by quantitatively evaluating the observation result of a part of the cross section of the welded portion.

  On the other hand, when the plated metal parts are welded together by resistance welding as described above, the plating layer is completely melted and the metal joining portion where the metals are joined together, and the plating layer is completely melted. It is not cut | disconnected, but it is a site | part where not only metals but metal plating layers are joined, Comprising: The plating joining site | part which is a site | part with a weak intensity | strength maintaining a joining state compared with a metal joining site | part is mixed. Therefore, when the plated metal parts are welded to each other by resistance welding, if the distribution in the welded portion between the metal joint portion and the plating joint portion is uneven in the above-described general inspection method, the quality of the welded state is judged. Even if it tries to evaluate quantitatively, the precision will fall.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a welding state inspection method that can suppress a decrease in the accuracy of the weld state determination.

  The inspection method of the welding state which solves the said subject test | inspects the welding state of the welding part by which the metal members which have a plating layer on a metal base material were resistance-welded. The welded state inspection method includes a first step of peeling the resistance-welded metal members from each other's welded portion, and at least one of the metal members after the first step. The second step of detecting surface information serving as an index representing the surface state of the side on which the metal was welded, and the resistance welding of the metal members before the first step using the surface information detected in the second step And a third step of determining whether the welded state of the welded portion is good or bad.

  According to the above configuration, in the first step, by peeling the metal members welded by resistance welding from each other's welded portion, the side on which the metal member of the other welded portion is welded is Weld marks that allow grasping of the metal joint part and the plating joint part appear. In the second step, it is possible to detect the distribution of the metal joint portion and the plating joint portion by detecting the surface state of the weld mark as a surface curve. In particular, in the second step, since the entire welding mark can be a detection target, even if there is a bias in the distribution of the metal joint part and the plating joint part, the metal joint part and the plating are performed. The joining site can be detected quantitatively. Thereby, even if there is a bias in the distribution of the metal joint portion and the plating joint portion in the third step, it is possible to determine the quality of the weld state without being influenced by this bias. Therefore, the general inspection method described in the above [Problems to be solved by the invention], which can be quantitatively evaluated while suppressing a decrease in accuracy of the quality determination of the welding state, and is observed only for a part of the welded portion, In comparison, the accuracy of the weld state determination can be improved.

  In the welding state inspection method, for example, the surface information is to detect a surface curve as the surface state on the side where the counterpart metal member in the welded portion after the first step is welded. In this process, based on the surface information, the plating layer is completely melted and the metal is bonded to each other, and the plating layer is not completely melted and the plating layers are bonded to each other instead of the metals. The surface area of at least one of the plating bonding sites is calculated, and the welded state is judged using the surface area.

  According to the said structure, the whole surface state comes to be detected three-dimensionally as surface information, and compared with the said general test | inspection method, a metal joining site | part and a plating joining site | part are detected quantitatively. Accuracy can be increased. Furthermore, since the surface area is used as a parameter for determining the quality of the welded state, a three-dimensional parameter is also used for the quality determination, which is advantageous for quantitative evaluation. Therefore, it is possible to improve the accuracy of the quality determination of the welding state.

  On the other hand, in the welding state inspection method, the surface information is to detect a surface curve as the surface state on the side where the counterpart metal member in the welded portion after the first step is welded. In this process, based on the surface information, the plating layer is completely melted and the metal is bonded to each other, and the plating layer is not completely melted and the plating layers are bonded to each other instead of the metals. It is also possible to calculate the two-dimensional area of at least one of the plating joining sites and determine whether the welding state is good or bad using the area.

  According to the said structure, the whole surface state comes to be detected three-dimensionally as surface information, and compared with the said general test | inspection method, a metal joining site | part and a plating joining site | part are detected quantitatively. Accuracy can be increased. On the other hand, since a two-dimensional area is used as a parameter for determining the quality of a welded state, two-dimensional information is used for the quality determination. However, since the two-dimensional area is collected from the entire welding trace, only a part of the welded part is observed. Compared with the above general inspection method, the accuracy of the quality determination of the welded part is improved. be able to.

  In the welding state inspection method, the metal joint part is at least one of a part of the welded part that has been shredded by a counterpart metal member and a part of the welded part that has been shredded from the counterpart metal member. It is desirable to be associated with this part.

According to the said structure, since a metal joining site | part can be detected quantitatively, the further improvement of the precision of the quality determination of a welding state can be aimed at.
Moreover, as an inspection object of the inspection method of the welding state, for example, a metal member having a plating layer may be a plate-like bus bar and a lead of an electronic component.

  In this case, there is a possibility that the lead of the electronic component may be bent after undergoing a process of peeling the resistance welded metal members from each other in accordance with the rigidity depending on the wire diameter of the lead of the electronic component. If there is, the surface information of the bus bar may be detected in the step of detecting the surface information. On the other hand, if there is no possibility that the lead of the electronic component is bent even after the process of peeling the metal members that are resistance welded from each other's welded portion, the lead of the bus bar and the electronic component is detected in the step of detecting the surface information. Any surface information may be detected. Thus, in the welding state inspection method, inspection according to the configuration of the inspection object can be performed, and the degree of freedom of application of inspection can be increased.

  According to the present invention, it is possible to suppress a decrease in the accuracy of the weld state determination.

The figure which shows the aspect of resistance welding with a bus-bar and a lead | read | reed. The figure which shows the state after resistance-welding a bus-bar and a lead | read | reed. The figure which shows a 1st process about the inspection process which determines the quality of a welding state. The figure which shows a 2nd process about the inspection process which determines the quality of a welding state. The photograph which shows the surface state of the bus bar after peeling off. It is a figure which shows a 3rd process about the inspection process which determines the quality of a welding state, Comprising: The figure which shows the detection method of the curve of the surface in 1st Embodiment, and the method of calculating a surface area. The figure which shows the detection result of the surface curve in the 2nd Embodiment, and the method of binarizing. The figure which shows the result binarized. The figure which shows the other aspect of resistance welding of a bus-bar and a lead | read | reed.

(First embodiment)
Hereinafter, a first embodiment of a welding state inspection method will be described. The inspection method of the welding state of this embodiment is a method for determining the quality of the welding state when the plated metal parts are resistance-welded to each other. The plated metal part is, for example, a plate-like bus bar or a lead such as a capacitor among a plurality of parts mounted on an electric device or the like.

  As shown in FIGS. 1 and 2, the plate-like bus bar 10 and the electronic component lead 20 are electrically connected by resistance welding so that their extending directions intersect each other. This resistance welding is so-called cross wire welding.

  The bus bar 10 is plated so as to have a tin plating layer 10b on the copper plate 10a for the purpose of suppressing corrosion due to oxidation or the like using a copper plate 10a made of copper, which is a conductive metal, as a metal base material. Similarly, the lead 20 is plated so that the copper wire 20a is a metal base material and a tin plating layer 20b is provided on the copper wire 20a. The copper plate 10a and the copper wire 20a have substantially the same copper content in copper. The wire diameter of the lead 20 is set smaller than the plate width and plate thickness of the bus bar 10.

  As shown in FIG. 1, in resistance welding, a bus bar 10 and a lead 20, which are objects to be welded with their longitudinal directions crossed, are sandwiched between welding electrodes 1 and 2 connected to a power source (not shown). The bus bar 10 and the lead 20 are joined by melting the bus bar 10 and the lead 20 by applying a current to the welding electrodes 1 and 2 while applying pressure in the joining direction of the bus bar 10 and the lead 20.

  As shown in FIG. 2, the bus bar 10 and the lead 20 after resistance welding are joined to each other via a welded portion 3 formed between the welding electrodes 1 and 2. The welded portion 3 includes a busbar-side welded portion 11 formed by melting the copper plate 10a and the plated layer 10b of the busbar 10, and a lead-side welded portion 21 formed by melting the copper wire 20a of the lead 20 and the plated layer 20b.

  In the welded portion 3 (each welded portion 11, 21), the plating layers 10 b, 20 b of the bus bar 10 and the lead 20 are completely melted, and the metal of the copper plate 10 a and the copper wire 20 a that are metal base materials are joined to each other. And the plating layers 10b and 20b of the bus bar 10 and the lead 20 are not completely melted, and the plating bonding sites where the plating layers 10b and 20b are joined together instead of the metals are mixed. In addition, a plating joining site | part has the boundary which is not joined completely between the plating layers 10b and 20b of the bus-bar 10 and the lead | read | reed 20, and the intensity | strength (henceforth, following) maintains a joining state compared with a metal joining location. This is a site where the “bonding strength” is weak.

  And the welding state of the resistance welding of the bus bar 10 and the lead 20 is judged as good or bad depending on whether or not a desired strength can be secured as the joint strength. The joint strength in the welded state after resistance welding is quantitatively evaluated by quantitatively detecting how many metal joints are present in the weld zone 3 (the region indicated by the phantom line A in FIG. 2). Can do.

Hereinafter, the inspection process (inspection method) for determining whether the welding state of the resistance welding of the bus bar 10 and the lead 20 is acceptable will be described in detail. This inspection process includes three main processes.
As shown in FIG. 3, in the first step of the inspection step, the resistance-welded bus bar 10 and the lead 20 are first peeled off from the respective welded portions 11 and 21. At this time, the lead 20 (lead-side weld 21) is peeled off from the bus bar 10 in a state where the bus bar 10 (bus-bar-side weld 11) is fixed.

  As shown in FIG. 4, in the second step of the inspection step, the welding that remains on the bus bar 10 after the lead 20 that is the counterpart metal member in the bus bar side welded portion 11 (welded portion 3) is peeled off in the first step. A surface curve Cs is detected (observed) as an index representing the surface state of the mark 4. In the present embodiment, the surface curve Cs is an example of surface information.

  Note that the lead 20 having a smaller wire diameter than the plate width and thickness of the bus bar 10 has lower rigidity than the bus bar 10 and is bent through the first step regardless of whether the welded state is good or not. , Likely to deform. Therefore, in the present embodiment, in the second step, the surface state of the weld mark 4 in the bus bar 10 that is difficult to be deformed, such as being bent, is compared with the lead 20 even after the first step.

  The surface curve Cs is detected by measuring the unevenness of the surface of the entire bus bar side welded portion 11 of the bus bar 10 (the region indicated by the imaginary line A in FIG. 4) using the 3D laser microscope 30. It is a so-called contour curve such as a roughness curve. The 3D laser microscope 30 is a so-called confocal laser microscope, and constructs a three-dimensional image by adjusting the focus of the laser (light beam) to various places on the measurement target (in this embodiment, the bus bar side welded portion 11). be able to. The 3D laser microscope 30 constructs data based on the curve Cs of the surface by an arithmetic processing unit 30a such as a microcomputer mounted therein, and three-dimensionally describes the entire welding mark 4 on an image display device such as a liquid crystal monitor (not shown). Images can be displayed as images.

  For example, in FIG. 5, as shown in the photograph of the actual state, the weld trace 4 remaining on the bus bar 10 is a portion where the lead 20 is partially cut into the bus bar 10 and joined by the pressurization during welding. Thus, a substantially semicircular groove along the contour of a part of the cylindrical outer surface of the lead 20 formed between the raised portion 4a that is raised compared to other portions and the adjacent raised portion 4a. A groove portion 4b having a shape appears. The surface of the groove 4b that appears here has random irregularities, and the “surface” described in “Claims” particularly refers to the surface of the groove 4b. Random irregularities on the surface of the groove 4b indicate traces of the metal joint part and traces of the plating joint part by color shading.

  Of the surface of the groove portion 4b, the darker part than the other part is a mark of the plating joint part, and is a plating layer mark 5 where the plating layer 10b of the bus bar 10 appears. Of the surface of the groove 4b, the lighter (thin) part of the surface than the plating layer mark 5 is the mark of the metal joint part, and the metal base material of the copper plate 10a of the bus bar 10 or the copper wire 20a of the lead 20 is It is the metal trace 6 which has appeared.

  In the metal trace 6, a concave dimple 6 a having a depth with respect to the plating layer trace 5 and a convex crest 6 b having a height with respect to the plating layer trace 5 are mixed. The dimple 6a is a part in a state where a part of the copper plate 10a of the bus bar 10 is torn off by the lead 20 (the state in which it is removed) through the first step. The peak portion 6b is a portion in a state where the bus bar 10 has stripped a part of the copper wire 20a of the lead 20 (taken state) through the first step.

  The dimples 6a and the crests 6b appear at a ratio corresponding to the combination of the metal base materials. In the present embodiment, the combination of the metal base materials is copper having substantially the same copper content, so that the dimples 6a and the peaks 6b appear on the surface of the groove 4b of the bus bar 10 at a substantially equal ratio. The same applies to the lead 20, and the bus bar 10, which is a metal member of the lead-side welded portion 21 (welded portion 3), is welded to the lead 20 peeled off from the busbar 10 in the first step. On the other side, dimples and peaks appear at an approximately equal ratio. In this case, the dimple is a portion where a part of the copper wire 20a of the lead 20 is torn off by the bus bar 10. Further, the peak portion in this case is a portion in a state where the lead 20 is torn off a part of the copper plate 10 a of the bus bar 10.

  Next, in the third step of the inspection step, using the surface curve Cs detected in the second step, the welded portion 3 (each welded portion 11) of the resistance welding of the bus bar 10 and the lead 20 before the first step. , 21). This quality determination is determined by the arithmetic processing unit 30a of the 3D laser microscope 30. The arithmetic processing unit 30a calculates the surface area Sa of the dimple 6a appearing on the surface of the groove part 4b of the bus bar 10 using the detection result of the surface curve Cs, and determines whether the surface area Sa exceeds the threshold value Sath. . The threshold value Sath is set as a quantitative value within a range in which a required bonding strength can be ensured according to the material of the bus bar 10 and the lead 20, the type of electrical equipment on which these are mounted, and the usage environment.

  For example, as shown in FIG. 6, the arithmetic processing unit 30 a uses a reference curve Csb (in FIG. 6) as an average line (curve) for the surface curve Cs as a boundary where the bus bar 10 and the lead 20 are joined. (Shown with a broken line). The reference curve Csb is substantially semicircular as a whole along a part of the outline of the lead 20, and substantially overlaps a portion of the surface curve Cs with relatively little unevenness, that is, the plating layer trace 5. And the arithmetic processing part 30a is a direction orthogonal to the tangential direction of the set reference curve Csb, and has a portion having a depth greater than a reference value (indicated by a one-dot chain line in FIG. 6) with respect to the reference curve Csb. The dimple 6a is associated. In the present embodiment, the reference value is set as a quantitative value (for example, 10 μm) within a range that can be defined as dimples, depending on the material of the bus bar 10 and the lead 20.

  Subsequently, the arithmetic processing unit 30a calculates a surface area Sa (part indicated by a thick line in FIG. 6) of the part associated as the dimple 6a. Thereafter, the arithmetic processing unit 30a compares the surface area Sa with the threshold value Sath, and when the surface area Sa exceeds the threshold value Sath, the quality determination of the welded state is “good”, that is, the necessary bonding strength can be secured. judge. On the other hand, the arithmetic processing unit 30a compares the surface area Sa with the threshold value Sath, and determines that the quality of the welded state is “No”, that is, the necessary joint strength cannot be ensured when the surface area Sa does not exceed the threshold value Sath. . Here, although described with reference to FIG. 6, the arithmetic processing unit 30 a calculates the surface area Sa three-dimensionally for the entire welding mark 4, and the first three-dimensionally for the entire welding mark 4. The weld state of the welded portion 3 (each welded portion 11, 21) of resistance welding of the bus bar 10 and the lead 20 before the process is judged as good or bad.

According to the present embodiment described above, the following operations and effects are achieved.
(1) In the first step, the bus bar 10 and the lead 20 welded by resistance welding are peeled off from the respective welded portions 11 and 21, so that the lead 20 of the busbar side welded portion 11 is welded to the side. The welding mark 4 which can grasp | ascertain that it was the said metal joining site | part and the said plating joining site | part appears. In the second step, by detecting the surface state of the weld mark 4 of the bus bar 10 as the surface curve Cs, it is possible to detect the distribution of the metal joint portion and the plating joint portion. In particular, in the second step, since the entire welding mark 4 of the bus bar 10 is a detection target, even if there is a bias in the distribution of the metal joint part and the plating joint part, the metal joint part and the above The plating bonding site can be detected quantitatively. Thereby, even if there is a bias in the distribution of the metal joint portion and the plating joint portion in the third step, it is possible to determine the quality of the weld state without being influenced by this bias. Therefore, the general inspection method described in the above [Problems to be solved by the invention], which can be quantitatively evaluated while suppressing a decrease in accuracy of the quality determination of the welding state, and is observed only for a part of the welded portion 3. Compared with, it is possible to improve the accuracy of the weld state determination.

  In the welding state inspection method of the present embodiment, the welded bus bar 10 and the lead 20 are fixed with a special resin, which is necessary in the general inspection method, and the welded portion 3 is cut and the welded portion 3 is cut. Processes such as polishing the cross section can be reduced, which is advantageous in terms of reducing the number of steps and labor.

  (2) When the surface state of the entire weld mark 4 of the bus bar 10 is detected in a three-dimensional manner by the 3D laser microscope 30 as the surface curve Cs, the metal joint portion and the plating joint portion are detected quantitatively. Can improve the accuracy. Furthermore, since the surface area Sa is used as a parameter for determining the quality of the welded state, a three-dimensional parameter is also used for the quality determination. Compared with the case where a parameter calculated by averaging or the like is used. Therefore, it is advantageous for quantitative evaluation. Therefore, it is possible to improve the accuracy of the quality determination of the welding state.

  (3) In the present embodiment, since the metal joint portion is detected in association with the portion of the bus bar side welded portion 11 that has been torn off by the lead 20, the metal joint portion can be quantitatively detected. Further, it is possible to further improve the accuracy of the weld state determination.

  (4) In this embodiment, when the lead 20 has a relatively large wire diameter and a certain degree of rigidity, the surface condition of the weld trace of the lead 20 is detected instead of the weld trace 4 of the bus bar 10. Thus, it is possible to determine the quality of the welding state. As described above, in the welding state inspection method of the present embodiment, it is possible to perform inspection according to the configuration of the inspection target, and the degree of freedom of application of inspection can be increased.

(Second Embodiment)
Next, a second embodiment of the welding state inspection method will be described. In addition, the same structure as embodiment already demonstrated attaches | subjects the same code | symbol, and the duplicate description is abbreviate | omitted.

  In the present embodiment, the surface curve Cs is measured using the 3D digital microscope 40 to measure the surface irregularities of the entire bus bar side welded portion 11 of the bus bar 10 (the region indicated by the phantom line A in FIG. 4). Is detected by The 3D digital microscope 40 uses a CCD camera and a high-resolution lens, and adjusts the focal point of the lens to various locations of the measurement target (in this embodiment, the bus bar side welded portion 11) and combines the respective images. 3D images can be constructed. In addition, when using the 3D digital microscope 40, compared with the 3D laser microscope 30, although the precision of the three-dimensional image constructed | assembled is low, the scale and cost of an installation can be held down. The 3D digital microscope 40 constructs data on the basis of the surface curve Cs by an arithmetic processing unit 40a such as a microcomputer mounted therein, and three-dimensionally describes the entire welding mark 4 on an image display device such as a liquid crystal monitor (not shown). Images can be displayed as images.

  In the third step of the inspection step of the present embodiment, the welded portion 3 (each of the resistance welding of the bus bar 10 and the lead 20 before the first step is used by using the surface curve Cs detected in the second step. The quality of the welded portions 11 and 21) is determined. This pass / fail determination is made by the arithmetic processing unit 40a of the 3D digital microscope 40. Using the detection result of the surface curve Cs, the arithmetic processing unit 40a calculates the two-dimensional total area St of the dimples 6a appearing on the surface of the groove part 4b of the bus bar 10, and the total area St sets the threshold value Stth. Determine if it has exceeded. The threshold value Stth is set as a quantitative value within a range in which a required bonding strength can be ensured according to the material of the bus bar 10 and the lead 20, the type of electrical equipment on which these are mounted, and the usage environment.

  For example, as shown in FIG. 7, when the curve Cs of the surface of the groove 4b on the VI-VI line in FIG. 4 is detected, the reference curve Csb (shown by a broken line in FIG. 7) is detected as in the first embodiment. On the other hand, a portion having a depth equal to or greater than a reference value (indicated by a one-dot chain line in FIG. 7) is associated as a dimple 6a. In FIG. 7, the same curve as in FIG. 6 is used as the surface curve Cs for convenience of explanation.

  Subsequently, as illustrated in FIG. 7, the arithmetic processing unit 40 a includes the total area St of the parts projected on the facing surface F facing the 3D digital microscope 40 (parts in FIG. 7). The part projected from the part indicated by the bold line is calculated.

  For example, as shown in FIG. 8, in the two-dimensional facing surface F, a part associated with the dimple 6a (dark part in FIG. 8) and a part other than the part associated with the dimple 6a (light in FIG. 8). (Thin part) is binarized and the total area St of the dark part of the binary is calculated by the arithmetic processing unit 40a.

  Thereafter, the arithmetic processing unit 40a compares the total area St with the threshold value Stth, and when the total area St exceeds the threshold value Stth, the quality determination of the welded state is “good”, that is, the necessary bonding strength is ensured. Judge as being done. On the other hand, the arithmetic processing unit 40a compares the total area St with the threshold value Stth, and if the total area St does not exceed the threshold value Stth, the quality determination of the welding state is “No”, that is, the necessary bonding strength is ensured. Judged as impossible.

According to this embodiment described above, in addition to the actions and effects of (1), (3) and (4) of the first embodiment, the following actions and effects can be obtained.
(5) The surface state of the weld mark 4 is detected as a surface curve Cs by the 3D digital microscope 40, and compared with the above general inspection method, the metal bonding portion and the plating bonding portion. It is possible to improve the accuracy when quantitatively detecting. On the other hand, since the total area St is used as a parameter for determining the quality of the welded state, two-dimensional information is used for the quality determination. However, since the total area St is collected from the entire welded portion 3 (weld mark 4), the quality of the welded portion is higher than that of the above general inspection method, which is observed only for a part of the welded portion. The accuracy of determination can be increased.

In addition, each said embodiment can also be implemented with the following forms.
In the first embodiment, instead of the surface area Sa, as the surface roughness of the surface curve Cs, for example, arithmetic mean roughness Ra or ten-point average roughness Rz is used to determine whether the welding state is good or bad. You can also. In this case, the surface curve Cs as shown in FIG. 6 is detected for a plurality of cross-sectional portions of the welding mark 4, the respective surface roughnesses are calculated, and these are used to determine the quality of the weld. That's fine. In addition, as a quality determination method, a ratio of the plating layer mark 5 and the metal mark 6 (including at least one of the dimple 6a and the peak portion 6b) may be used. In any case, the accuracy of the quality determination of the welded portion can be improved as compared with the above general inspection method.

  In the first embodiment, when the surface curve Cs is detected, a stylus-type detection device is used, or the 3D digital microscope 40 is similar to the second embodiment, depending on the accuracy of determining the quality of the welding state. May be used.

  In the second embodiment, instead of calculating the total area St by the arithmetic processing unit 40a, the total area St may be artificially calculated. In this case, the arithmetic processing unit 40a may display the binarized result on the image display device as shown in FIG. In addition, as a pass / fail determination method, the distribution of the dimples 6a, such as the sum of areas per unit area, may be statistically analyzed. Even in this case, if the information collected from the entire welded portion 3 (weld mark 4) is used, the accuracy of the quality determination of the welded portion can be improved as compared with the above general inspection method. it can.

-In 2nd Embodiment, when detecting the curve Cs of the surface, you may use 3D digital microscopes from which detection accuracy differs in the range in which the precision which determines the quality of a welding state is accept | permitted.
In each embodiment, as shown in FIG. 9, a projection (projection) 10c is provided in advance on the bus bar 10 by pressing or the like, and the lead 20 is resistance-welded to the projection 10c, so-called projection welding. It can also be used to determine the quality of the state.

  In each embodiment, instead of the part associated with the dimple 6a, the quality of the welded state may be determined by calculating the surface area Sa of the part associated with the mountain part 6b and the total area St. . Even in this case, since the surface area Sa and the total area St are collected from the entire welded portion 3 (weld mark 4), the quality of the welded portion is determined as compared with the above general inspection method. Accuracy can be increased.

In each embodiment, the reference curve Csb may be set based on a curve obtained by virtually extending a portion with relatively little unevenness.
In each embodiment, for example, if the total area St is close to the threshold value as a result of the pass / fail determination by the welding state inspection method of the second embodiment, the pass / fail determination is further performed by the inspection method of the first embodiment. Even if they are used in combination, they are effective.

  -In each embodiment, although what carried out resistance welding of the bus-bar 10 and the lead | read | reed 20 was actualized, it is not restricted to this. For example, it can be applied to resistance welding of metals such as resistance welding of leads of electronic parts or resistance welding of a bus bar to a housing.

  Each modification may be applied in combination with each other. For example, the configuration of injection welding shown in FIG. 9 and the configuration of other modifications may be applied in combination with each other.

  DESCRIPTION OF SYMBOLS 1, 2 ... Electrode for welding, 3 ... Welding part, 4 ... Welding mark, 4a ... Raised part, 4b ... Groove part, 5 ... Plating layer mark, 6 ... Metal mark, 6a ... Dimple, 6b ... Mountain part, 10 ... Busbar DESCRIPTION OF SYMBOLS 10a ... Copper plate, 10b ... Plating layer, 11 ... Busbar side welding part, 20 ... Lead, 20a ... Copper wire, 20b ... Plating layer, 21 ... Lead side welding part, 30 ... 3D laser microscope, 30a ... Arithmetic processing part, 40 ... 3D digital microscope, 40a ... arithmetic processing unit, Cs ... surface curve, Csb ... reference curve, Sa ... surface area, Sath ... threshold, St ... total area, Stth ... threshold.

Claims (5)

A method for inspecting a welding state of a welded portion in which metal members having a plating layer on a metal base material are resistance-welded,
A first step of peeling the resistance-welded metal members from each other's welds;
A second step of detecting surface information serving as an index representing a surface state of the welded portion on the side where the counterpart metal member is welded, with respect to at least one of the metal members after the first step;
Using the surface information detected in the second step, a third step of determining pass / fail of the welding state of the resistance welding portion between the metal members before the first step;
Inspection method of welding state including The surface information is to detect a surface curve as the surface state of the welded metal member in the welded part after the first step,
In the third step, based on the surface information, the plating layer is completely melted and the metal is joined to each other, and the plating layer is not completely melted and not the metals. The weld state inspection method according to claim 1, wherein a surface area of at least one of the plating joining sites where the plating layers are joined is calculated, and the weld state is judged good or bad using the surface area. The surface information is to detect a surface curve as the surface state of the welded metal member in the welded part after the first step,
In the third step, based on the surface information, the plating layer is completely melted and the metal is joined to each other, and the plating layer is not completely melted and not the metals. The weld state inspection method according to claim 1, wherein a two-dimensional area of at least one of the plating joining portions where the plating layers are joined is calculated, and the weld state is determined to be good or bad using the area.   The metal joint portion is associated with at least one of a portion of the welded portion that has been shredded by a mating metal member and a portion of the welded portion that has been shredded from the mating metal member. The welding state inspection method according to claim 2 or claim 3.   The said metal member which has a plating layer is a plate-shaped bus bar and the lead of an electronic component, The inspection method of the welding state as described in any one of Claims 1-4.