solid phase bonding device

Abstract

To provide a solid-phase bonding apparatus that can efficiently determine the quality of the bonding. [Solution] The solid-state bonding apparatus 1 includes pressure shafts 11 and 12 that press the first workpiece W10 and the second workpiece W20 from both sides, electrodes 21 and 22 arranged adjacent to the pressure shafts 11 and 12, respectively, and a control device 30 that controls the pressure shafts 11 and 12 so that they apply a load to the first workpiece W10 and the second workpiece W20 in the thickness direction, and also controls the current flowing between the electrodes 21 and 22. The control device 30 includes a storage device 33 that stores displacement data showing the change in the distance between the ends of the pressure shafts 11 and 12 and load data showing the change in the load applied to the pressure shafts 11 and 12 when the first workpiece W10 and the second workpiece W20 are bonded together, and a calculation device 31 that determines the bonding state of the first workpiece W10 and the second workpiece W20 based on the displacement data and load data stored in the storage device 33.

Description

Technical Field

[0001] The present disclosure relates to a solid-phase bonding device.

Background Art

[0002] Japanese Patent No. 7242112 (Patent Document 1) discloses a solid-phase bonding device including a pressurizing mechanism including a pressing portion and an energization mechanism including a pair of welding electrodes. The solid-phase bonding device disclosed in Japanese Patent No. 7242112 (Patent Document 1) is configured to energize two metal plates by a pair of welding electrodes to heat each metal plate, and press the two metal plates in a direction orthogonal to the metal plates by the pressing portion.

[0003] According to the solid-phase bonding device disclosed in Japanese Patent No. 7242112 (Patent Document 1), by a bonding method having a temperature-rising step of raising the temperature of the bonding interface and forming a softened region near the bonding interface, and a stress-applying step of applying an external stress greater than the yield strength of the metal plate at a desired bonding temperature to the softened region, the softened region is locally deformed to bond the metal plates together.

[0004] In this specification, a bonding method as disclosed in Japanese Patent No. 7242112 (Patent Document 1) that prevents strength reduction and the like due to melting of metal by a large current by bonding in a solid-phase state in a low-temperature range without melting the metal is called "solid-phase bonding".

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the solid-phase joining method disclosed in Japanese Patent Publication No. 7242112 (Patent Document 1), the formation of molten solidification structures and heat-affected zones at the joint is suppressed compared to resistance spot welding and the like, so it is expected that the strength and toughness of the joint will be improved.

[0007] However, solid-state bonding is a relatively new technique, and there were no existing quality control methods for mass production.

[0008] The purpose of this disclosure is to provide a solid-phase bonding apparatus that can efficiently determine bonding quality. [Means for solving the problem]

[0009] This disclosure relates to a solid-state bonding apparatus. The solid-state bonding apparatus comprises a pair of pressure shafts that press a first workpiece and a second workpiece made of metal from both sides in the thickness direction, a pair of electrodes arranged adjacent to each of the pair of pressure shafts, and a control device that controls the pair of pressure shafts so that they apply a load to the first workpiece and the second workpiece in the thickness direction, and controls the current flowing between the pair of electrodes. The control device includes a storage device that stores displacement data showing the change in the distance between the ends of the pair of pressure shafts and load data showing the change in the load applied to the pair of pressure shafts when the first workpiece and the second workpiece are bonded together, and a calculation device that determines the bonding state of the first workpiece and the second workpiece based on the displacement data and load data stored in the storage device. [Effects of the Invention]

[0010] According to the solid-phase bonding apparatus of this disclosure, the quality of the joint can be efficiently determined after bonding, thereby improving production efficiency. [Brief explanation of the drawing]

[0011] [Figure 1] This figure schematically shows the configuration of a solid-phase bonding apparatus 1 according to one embodiment of the present disclosure. [Figure 2] This is a diagram (load-displacement diagram) showing the relationship between load and displacement recorded during joining in a solid-state bonding device. [Figure 3] This figure shows the relationship between the judgment frame used for the judgment and the waveform of the load line. [Figure 4] This figure shows an example of the quality judgment result for points joined using the joining device shown in Figure 1. [Figure 5] This figure shows the results of a tensile test to determine the joint strength of joint points P1 to P6 in Figure 4. [Figure 6] This diagram shows the position of judgment frame F1, the judgment items, and the judgment conditions. [Figure 7] This diagram shows the position of judgment frame F2, the judgment items, and the judgment conditions. [Figure 8] This diagram shows the load-displacement diagram and the judgment frames F1 and F2 superimposed on each other. [Figure 9] This is a magnified view of the area around the judgment frame F1 in Figure 8. [Figure 10] This is a magnified view of the area around the judgment frame F2 in Figure 8. [Figure 11] This diagram shows the judgment results for judgment frame F1. [Figure 12] This figure shows the judgment results for judgment frame F2. [Figure 13] This is a flowchart to explain the decision-making process. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following descriptions will include several modified embodiments, but it has been intended from the outset that the configurations described in each embodiment may be combined as appropriate. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0013] FIG. 1 is a diagram schematically showing the configuration of a solid-phase bonding apparatus 1 according to an embodiment of the present disclosure. The solid-phase bonding apparatus 1 forms a softened region at the interface of a plurality of workpieces W10 and W20 that are overlapped with each other by applying electricity, and plastically deform the softened region to bond the plurality of workpieces W10 and W20 together in a solid state without melting them.

[0014] The plurality of workpieces W10 and W20 include a first workpiece W10 and a second workpiece W20. Each workpiece W10 and W20 is made of a metal such as iron or aluminum. Each workpiece W10 and W20 is formed, for example, in a flat plate shape.

[0015] As shown in FIG. 1, the solid-phase bonding apparatus 1 includes a solid-phase bonding device 10, a control device 30, and an ammeter 35. The solid-phase bonding device 10 includes a pair of pressure shafts 11 and 12, a pair of electrodes 21 and 22, and a load sensor 40.

[0016] The pair of pressure shafts 11 and 12 includes a first pressure shaft 11 and a second pressure shaft 12. The pair of pressure shafts 11 and 12 can press the first workpiece W10 and the second workpiece W20 from both sides in the thickness direction in which the plate-shaped workpieces are overlapped. The pair of pressure shafts 11 and 12 is driven by a drive source (such as a servo press) not shown in the figure.

[0017] The first pressure shaft 11 is long. The first pressure shaft 11 can press the first workpiece W10 so that the first workpiece W10 is plastically deformed. Specifically, the first pressure shaft 11 can press the first workpiece W10 so that a protrusion W11 is formed on the first workpiece W10. The first pressure shaft 11 is made of, for example, tungsten carbide. In the present embodiment, the first pressure shaft 11 is formed in a cylindrical shape. The first pressure shaft 11 has a pressing surface 11a that presses the first workpiece W10. The pressing surface 11a is an end surface of the first pressure shaft 11. The pressing surface 11a is formed in a circular shape.

[0018] The second pressure shaft 12 has the same configuration as the first pressure shaft 11. The central axis of the second pressure shaft 12 is located on the extension of the central axis of the first pressure shaft 11, and the pressing surface 12a of the second pressure shaft 12 is positioned to face the pressing surface 11a of the first pressure shaft 11. Note that the first pressure shaft 11 and the second pressure shaft 12 may have shapes other than cylindrical.

[0019] The load sensor 40 is installed, for example, on the first pressurizing shaft 11. In this embodiment, a load cell is used as the load sensor 40. Note that the installation location of the load sensor 40 is not limited to the first pressurizing shaft 11.

[0020] The pair of electrodes 21, 22 includes a first electrode 21 and a second electrode 22. The pair of electrodes 21, 22 can energize the first workpiece W10 and the second workpiece W20 while in contact with them. Voltage and current are supplied to the pair of electrodes 21, 22 from a power supply unit (not shown).

[0021] The first electrode 21 is capable of contacting the portion of the first workpiece W10 that is pressurized by the first pressurizing shaft 11. In this embodiment, the first electrode 21 is formed in a cylindrical shape that surrounds the first pressurizing shaft 11. A gap is provided between the inner circumferential surface of the first electrode 21 and the outer circumferential surface of the first pressurizing shaft 11. The first electrode 21 is made of, for example, copper. The first electrode 21 has a contact surface 21a that contacts the first workpiece W10. The contact surface 21a is formed in an annular shape. However, the shape of the contact surface 21a is not limited to an annular shape.

[0022] The second electrode 22 has the same configuration as the first electrode 21. The second electrode 22 is capable of contacting the area surrounding the part of the second workpiece W20 that is pressurized by the second pressurizing shaft 12. The second electrode 22 is positioned such that its central axis lies on the extension of the central axis of the first electrode 21, and its contact surface 22a faces the contact surface 21a of the first electrode 21.

[0023] The ammeter 35 detects the value of the current X that flows from the pair of electrodes 21 and 22 to each projection W11 and W21.

[0024] The control device 30 comprises an arithmetic unit 31, a memory 32, a storage device 33, and an input / output interface 34. These components are connected via a bus.

[0025] The arithmetic unit 31 is a computing entity (computer) that performs predetermined processing. The arithmetic unit 31 is composed of a processor such as a CPU (Central Processing Unit), MPU (Micro-Processing Unit), TPU (Tensor Processing Unit), or GPU (Graphics Processing Unit). While a processor, as an example of the arithmetic unit 31, has the function of performing predetermined processing by executing a predetermined program, some or all of these functions may be implemented using dedicated hardware circuits such as an ASIC (Application Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array). The term "processor" is not limited to processors in the narrow sense that execute processing using a stored-program method, such as a CPU, MPU, TPU, or GPU, but may also include hardwired circuits such as ASICs or FPGAs. Furthermore, the arithmetic unit 31 is not limited to von Neumann type computers such as CPUs or GPUs, but may also consist of non-von Neumann type computers such as quantum computers or optical computers. The arithmetic unit 31 described above can also be read as a processing circuitry that performs predetermined processing. The arithmetic unit 31 may consist of one chip or multiple chips. Furthermore, the processor and associated processing circuits may consist of multiple computers interconnected by wired or wireless connections via a local area network or wireless network. The processor and associated processing circuits may also consist of a cloud computer that remotely performs calculations based on input data and outputs the calculation results to other devices located at a distance.

[0026] The memory 32 includes a storage area (for example, a working area) for storing program code or work memory when the arithmetic unit 31 executes various programs. Examples of memory 32 include volatile memory such as DRAM and SRAM, or non-volatile memory such as ROM and flash memory.

[0027] The storage device 33 stores various programs and data executed by the arithmetic unit 31. For example, the storage device 33 stores a control program 330 that controls a pair of pressurizing shafts 11, 12 and a pair of electrodes 21, 22, which are executed by the arithmetic unit 31. The storage device 33 may be one or more non-transitory computer-readable media or one or more computer-readable storage media. Examples of storage devices 33 include HDDs (Hard Disk Drives) and SSDs (Solid State Drives).

[0028] The input / output interface 34 receives values ​​acquired by the acquisition units, such as the load sensor 40 and the ammeter 35.

[0029] The control device 30 controls a pair of pressurizing shafts 11, 12 and a pair of electrodes 21, 22. Specifically, the control device 30 controls the load acting on the first workpiece W10 and the second workpiece W20 from each of the pair of pressurizing shafts 11, 12, the load acting on the first workpiece W10 and the second workpiece W20 from each of the pair of electrodes 21, 22, the voltage applied to the pair of electrodes 21, 22, and the amount of indentation of the pair of pressurizing shafts 11, 12 and the pair of electrodes 21, 22. The control device 30 controls the current X flowing through the pair of electrodes 21, 22 by controlling the voltage applied to the pair of electrodes 21, 22.

[0030] The control device 30 applies a load F (see Figure 1) to the first workpiece W10 and the second workpiece W20 from a pair of pressurizing shafts 11 and 12 such that protrusions W11 and W21 that contact each other are formed on each of the first workpiece W10 and the second workpiece W20. The control device 30 also performs the operation of energizing the first workpiece W10 and the second workpiece W20. Specifically, the control device 30 applies a load F to the first workpiece W10 and the second workpiece W20 from a pair of pressurizing shafts 11 and 12, and while the contact surface 21a of the first electrode 21 is in contact with the area of ​​the first workpiece W10 that is pressurized by the first pressurizing shaft 11, and the contact surface 22a of the second electrode 22 is in contact with the area of ​​the second workpiece W20 that is pressurized by the second pressurizing shaft 12, the control device 30 energizes the first workpiece W10 and the second workpiece W20. The control device 30 controls the flow of current X, shown by the dashed line, between the pair of electrodes 21 and 22 via the respective protrusions W11 and W21.

[0031] Each protrusion W11, W21 is softened by the flow of current X. In the solid-state bonding apparatus 1 of this embodiment, the control device 30 applies a load F to the first workpiece W10 and the second workpiece W20 while applying current X to soften each protrusion W11, W21. As a result, in this embodiment, the first workpiece W10 and the second workpiece W20 can be joined at the positions of each protrusion W11, W21.

[0032] Figure 2 is a diagram (load-displacement diagram) showing the relationship between load and displacement recorded during joining in a solid-state bonding apparatus. In Figure 2, the horizontal axis represents the displacement (change in position) of the pressurizing axis, and the vertical axis represents the load applied to the pressurizing axis.

[0033] In this embodiment, the displacement of the pressure shaft refers to the displacement of the upper pressure shaft 11 when the position of the lower pressure shaft 12 is fixed. Alternatively, the displacement of the pressure shaft may also refer to the displacement of the lower pressure shaft 12 when the position of the upper pressure shaft 11 is fixed. Furthermore, if both the upper and lower pressure shafts 11 and 12 move, the displacement of the pressure shaft may also be the change in distance from the tip of pressure shaft 11 to the tip of pressure shaft 12. In other words, the displacement of the pressure shaft is the amount by which the workpieces W10 and W20 are pressed from above and below. In this case, the larger the displacement of the pressure shaft, the shorter (narrower) the distance between the tips of the upper and lower pressure shafts becomes.

[0034] In the solid-state bonding shown in this embodiment, the load-displacement diagram, which shows the changes in load and displacement values, shows two peaks enclosed in a rectangular frame, as shown in Figure 2.

[0035] The first peak represents the waveform during the operation in which a load F is applied to the first workpiece W10 and the second workpiece W20 from a pair of pressurizing shafts 11 and 12 so that protrusions W11 and W21 that come into contact with each other are formed on the first workpiece W10 and the second workpiece W20, respectively (hereinafter referred to as the protrusion formation process). In the waveform of Figure 2, the protrusion formation process corresponds to the period from when the load is increased from 0 to 30 kN until the load is reduced to near zero.

[0036] The second peak represents the waveform during the operation in which a load F is applied to the first workpiece W10 and the second workpiece W20 to join them together, while a current X is passed to soften each protrusion W11 and W21 (hereinafter referred to as the joining press-fitting process). In the waveform of Figure 2, the joining press-fitting process occurs after the protrusion formation process is completed, from when the load is increased from near zero to 50kN, and then reduced to near zero.

[0037] In this embodiment, quality is determined based on the relationship between load and displacement during joining. Primarily, the load and displacement values ​​from two processes are used: the projection formation process (also called the joining preparation process) and the joining pressing process (also called the joining process).

[0038] The inventors of this application have discovered a method for determining the quality of a joint from the waveform near the load peak point in the protrusion formation process and the waveform near the load peak point in the joining press process.

[0039] In this embodiment, based on prior experiments and analysis results, the range indicating a good product is estimated in the plane of the load-displacement diagram, a judgment frame is set based on that value, and the good / bad result is output from the positional relationship between the load-displacement diagram and the judgment frame during actual joining.

[0040] Figure 3 shows the relationship between the judgment frame used for judgment and the waveform of the load line. If the dashed-dotted frame shown in Figure 3 is the judgment frame, the coordinates used to calculate the positional relationship between the load displacement diagram and the judgment frame include the intersection point XA of the entry path into the judgment frame (load path) and the judgment frame, the intersection point XB of the exit path (unload path) and the judgment frame, the vertex PA of the upward convexity, and the vertex PB of the downward convexity. Note that the vertex PB of the downward convexity may not exist in some cases.

[0041] [Specific example] As an example of implementation, the results of good quality judgment for a steel plate with a thickness of 1.6 mm and a base material strength of 980 MPa are shown. Figure 4 shows an example of the good / bad quality judgment results for a point joined using the joining device shown in Figure 1. Figure 5 shows the results of a tensile test of the joint strength of the joint points P1 to P6 in Figure 4.

[0042] The results shown in Figures 4 and 5 represent the results obtained under conditions where misalignment of the pressurizing shafts 11 and 12 of the joining device is a concern. To simulate joining failures, the amount of misalignment (mm) was varied to 0, 0.3 (mm), 0.4 (mm), 0.6 (mm), 0.8 (mm), and 1 (mm), and tests were conducted in advance to determine at which amount of misalignment a joining failure occurred.

[0043] For example, if the required tensile strength in Figure 5 is 20-25 kN, then joints P1-P3 will meet the required strength, while joints P4-P6 will not. As shown in Figure 4, the strength test results will be OK (pass) for joints P1-P3 and NG (fail) for joints P4-P6.

[0044] Therefore, if the misalignment is within 0.4 mm, the strength will meet the requirements, but if the misalignment is 0.6 mm or more, the strength will not meet the requirements.

[0045] Based on the above results, two judgment frames F1 and F2 are set in the load-displacement diagram. Figure 6 shows the position, criteria, and conditions for judgment frame F1. Figure 7 shows the position, criteria, and conditions for judgment frame F2. Figure 8 shows the load-displacement diagram superimposed with judgment frames F1 and F2.

[0046] As shown in Figure 6, when the junction condition is a current value of 6kA, the judgment frame F1 is set at positions where the top edge is 32kN, the bottom edge is 28kN, the left edge is 1.3mm, and the right edge is 1.5mm. This judgment frame F1 is used in common for the judgment items (vertices PA, PB, intersections XA, XB).

[0047] The criteria for determining the judgment frame F1 are expressed as follows, using the vertices PA and PB and intersections XA and XB shown in Figure 3: conditions 1 to 4. Condition 1) The coordinates of the vertex PA are within the judgment frame F1, and, Condition 2) The coordinates of vertex PB are within the judgment frame F1, and, Condition 3) The intrusion path (load path) passes through the left side of the judgment frame F1, that is, the intersection XA is on the left side, Condition 4) The exit path (unloading path) passes through the bottom edge of the judgment frame F1, i.e., the intersection XB is on the bottom edge.

[0048] Condition 2) is satisfied if the vertex PB does not lie on the load-displacement diagram.

[0049] If any of the above conditions 1-4 result in an "NG" (Not Good) judgment, the overall judgment for the judgment frame F1 at that connection point will be "NG".

[0050] Furthermore, as shown in Figure 7, when the junction condition is a current value of 6kA, the judgment frame F2 is set at positions where the top edge is 55kN, the bottom edge is 45kN, the left edge is 2.0mm, and the right edge is 2.5mm. This judgment frame F2 is used in common for the judgment items (vertices PA, PB, intersections XA, XB).

[0051] The criteria for determining the judgment frame F2 are expressed as follows, using the vertices PA and PB and intersections XA and XB shown in Figure 3: conditions 5 to 8. Condition 5) The coordinates of the vertex PA are within the judgment frame F2, and, Condition 6) The coordinates of vertex PB are within the judgment frame F2, and, Condition 7) The intrusion path (load path) passes through the lower edge of the judgment frame F2, that is, the intersection XA is on the lower edge, Condition 8) The exit path (unloading path) passes through the bottom edge of the judgment frame F2, i.e., the intersection XB is on the bottom edge.

[0052] Condition 6) is satisfied if the vertex PB does not lie on the load-displacement diagram.

[0053] If any of the above conditions 5-8 result in an "NG" (Not Good) judgment, the overall judgment for the judgment frame F2 at that connection point will be "NG".

[0054] Figure 9 is a magnified view of the area around judgment frame F1 in Figure 8. Figure 10 is a magnified view of the area around judgment frame F2 in Figure 8. Figure 11 shows the judgment result for judgment frame F1. Figure 12 shows the judgment result for judgment frame F2.

[0055] Referring to Figures 9 and 11, the determination results for joint points P1 to P6 relative to the determination frame F1 are explained below.

[0056] The junction points P1, P2, and P3 passed all evaluation criteria for vertices PA, PB, and intersections XA and XB, resulting in an overall evaluation of OK.

[0057] For junctions P4, P5, and P6, the judgment results for vertex PA and intersection XB are OK, but the judgment results for vertex PB and intersection XA are NG, resulting in an overall judgment of NG.

[0058] Referring to Figures 10 and 12, the determination results for the joint points P1 to P6 relative to the determination frame F2 are explained below.

[0059] The junction points P1, P2, P3, P5, and P6 all passed the evaluation for all criteria related to vertices PA, PB, and intersections XA, XB, resulting in an overall evaluation of OK.

[0060] On the other hand, for junction point P4, the judgment results for vertex PB and intersection points XA and XB are OK, but the judgment result for vertex PA is NG, resulting in an overall judgment of NG.

[0061] The judgment is performed on both judgment frame F1 and judgment frame F2, and if either is deemed defective, the entire assembly is considered defective. From the judgment results in Figures 11 and 12, joint points P1 to P3 are judged as OK, and joint points P4 to P6 are judged as NG. This judgment result is consistent with the results in Figures 4 and 5.

[0062] The required tensile strength varies depending on the application and plate thickness, and will be adjusted accordingly. Consequently, the boundary for the amount of misalignment that satisfies the strength requirement also changes, and the positions of judgment frames F1 and F2 will be adjusted accordingly.

[0063] The procedure for the judgment process described in Figures 6 to 11 above will now be explained. Figure 13 is a flowchart illustrating the judgment process.

[0064] First, in step S1, the control device 30 performs a protrusion formation process. This creates protrusions at the contact points of the workpieces W10 and W20, making it easier for current to concentrate. In this case, in principle, no current is passed through electrodes 21 and 22, but a very weak current that does not contribute to the softening of the workpiece metal may be passed through in order to detect contact.

[0065] Next, in step S2, the control device 30 performs a bonding press process. At this time, the control device 30 applies a load between the pressurizing shafts 11 and 12 while passing an electric current between the electrodes, thereby solid-state bonding the first workpiece W10 and the second workpiece W20. The current value at this time is such that it contributes to the softening of the metal of the workpiece but does not melt the workpiece.

[0066] Next, in step S3, the control device 30 saves a dataset containing displacement data and load data for the completed joint point to the storage device 33. Then, in step S4, the arithmetic unit 31 in the control device 30 creates a load-displacement diagram from the dataset saved in the storage device 33 and analyzes the relationship between the load-displacement diagram and the judgment frames F1 and F2. For judgment frame F1, it is determined whether conditions 1 to 4 are met, as shown in Figure 10. For judgment frame F2, it is determined whether conditions 5 to 8 are met, as shown in Figure 11.

[0067] In step S5, the arithmetic unit 31 determines whether the junction point dataset satisfies all of conditions 1 to 4 (OK) or not (NG). If all of conditions 1 to 4 are OK (YES in S5), in step S7 the arithmetic unit 31 determines that the result for judgment frame F1 is OK and proceeds to step S8. On the other hand, if even one of conditions 1 to 4 is NG (NO in S5), in step S7 the arithmetic unit 31 determines that the result for judgment frame F1 is NG and proceeds to step S12.

[0068] In step S8, the arithmetic unit 31 determines whether the junction point dataset satisfies all conditions 5 to 8 (OK) or not (NG). If all conditions 5 to 8 are OK (YES in S8), in step S9 the arithmetic unit 31 determines that the result for judgment frame F2 is OK and proceeds to step S10. On the other hand, if even one of conditions 5 to 8 is NG (NO in S8), in step S11 the arithmetic unit 31 determines that the result for judgment frame F2 is NG and proceeds to step S12.

[0069] In step S10, the arithmetic unit 31 determines that the final judgment regarding the joint point is OK. On the other hand, in step S12, the arithmetic unit 31 determines that the final judgment regarding the joint point is NG. The final judgment result obtained in step S10 or S12 is recorded or displayed as necessary.

[0070] In this way, the condition of the joint point can be determined based on the relationship between displacement data and load data, which are generally monitored during solid-state bonding, making it easy to introduce condition determination into the manufacturing line. Furthermore, it becomes possible to detect defective joint points early, thus preventing solid-state bonding equipment from continuously producing defective joints.

[0071] In this embodiment, the judgment frame was set in the load-displacement diagram and the judgment conditions were set, but other methods may be used to distinguish between normal and abnormal joint points using the waveform of the load-displacement diagram.

[0072] [summary] (1) This disclosure relates to a solid-state bonding apparatus 1. The solid-state bonding apparatus 1 includes a pair of pressure shafts 11, 12 that press a first workpiece W10 and a second workpiece W20 made of metal from both sides in the thickness direction, a pair of electrodes 21, 22 arranged adjacent to the pair of pressure shafts 11, 12, and a control device 30 that controls the pair of pressure shafts 11, 12 so that they apply a load to the first workpiece W10 and the second workpiece W20 in the thickness direction, and controls the current flowing between the pair of electrodes 21, 22. The control device 30 includes a storage device 33 that stores displacement data showing the change in the distance between the ends of the pair of pressure shafts 11, 12 and load data showing the change in the load applied to the pair of pressure shafts 11, 12 when the first workpiece W10 and the second workpiece W20 are bonded together, and a calculation device 31 that determines the bonding state of the first workpiece W10 and the second workpiece W20 based on the displacement data and load data stored in the storage device 33.

[0073] (2) In the solid-state joining apparatus described in paragraph 1, the control device 30 is configured to perform a protrusion formation process in which a load is applied between a pair of pressurizing shafts 11 and 12 to form a protrusion on at least one of the first workpiece W10 and the second workpiece W20 when joining the first workpiece W10 and the second workpiece W20, and a joining pressurizing process in which a load is applied between a pair of pressurizing shafts 11 and 12 while an electric current is flowed between a pair of electrodes 21 and 22 after the protrusion formation process to solid-state join the first workpiece W10 and the second workpiece W20. The calculation device 31 is configured to determine the joining state of the first workpiece W10 and the second workpiece W20 based on the displacement data and load data obtained in the protrusion formation process or the joining pressurizing process.

[0074] (3) In the solid-state joining apparatus described in paragraph 2, as shown in Figure 3, the calculation device 31 is configured to determine the joining state between the first workpiece W10 and the second workpiece W20 based on the trajectory traced by the points indicated by the displacement data and load data on the plane indicated by the first and second axes during the joining process, when the displacement data is indicated on the first axis and the load data is indicated on the second axis intersecting the first axis.

[0075] (4) In the solid-state bonding apparatus described in paragraph 3, as shown in Figure 3, the calculation device 31 is configured to determine the bonding state between the first workpiece W10 and the second workpiece W20 based on the position of the vertex PA (or PB) indicated by the trajectory.

[0076] (5) In the solid-state bonding apparatus described in paragraph 3, as shown in Figure 3, the calculation device 31 is configured to determine the bonding state between the first workpiece W10 and the second workpiece W20 based on the position (XA) where the trajectory enters a predetermined region (F1 or F2) as the bonding process progresses.

[0077] (6) In the solid-state bonding apparatus described in paragraph 3, as shown in Figure 3, the calculation unit 31 is configured to determine the bonding state between the first workpiece and the second workpiece based on the position (XB) where the trajectory exits a predetermined region (F1 or F2) as the bonding process progresses.

[0078] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0079] 1 Joining device, 10 Joining equipment, 11,12 Pressurizing shafts, 11a,12a Pressing surfaces, 21,22 Electrodes, 21a,22a Contact surfaces, 30 Control device, 31 Calculation unit, 32 Memory, 33 Storage device, 34 Input / Output interface, 35 Ammeter, 40 Load sensor, 330 Control program, F1,F2 Judgment frame, P1,P2,P3,P4,P5,P6 Joining points, PA,PB Vertices, W10,W20 Workpiece, W11,W21 Projections, XA,XB Intersections.

Claims

1. A pair of pressure shafts that press a first workpiece and a second workpiece made of metal from both sides in the thickness direction, A pair of electrodes are arranged adjacent to each of the pair of pressurizing shafts, The system includes a control device that controls the pair of pressure shafts so that they apply a load to the first and second workpieces in the thickness direction, and controls the current flowing between the pair of electrodes, The control device is A storage device that stores displacement data showing the change in the distance between the ends of the pair of pressurizing shafts and load data showing the change in the load applied to the pair of pressurizing shafts when joining the first workpiece and the second workpiece, A solid-state joining apparatus including a calculation device that determines the joining state between the first workpiece and the second workpiece based on the displacement data and load data stored in the memory device.

2. The control device performs the joining process on the first workpiece and the second workpiece. A protrusion forming process is performed by applying a load between the pair of pressurizing shafts to form a protrusion on at least one of the first workpiece and the second workpiece. The system is configured to perform a bonding press process in which, after the projection forming process, a load is applied between the pair of pressurizing shafts while an electric current is passed between the pair of electrodes to solid-state bond the first workpiece and the second workpiece. The solid-phase joining apparatus according to claim 1, wherein the calculation device is configured to determine the joining state between the first workpiece and the second workpiece based on the displacement data and load data obtained in the projection forming process or the joining pressing process.

3. The solid-state joining apparatus according to claim 2, wherein the calculation device is configured to determine the joining state of the first workpiece and the second workpiece based on the trajectory traced by the point indicated by the displacement data and the load data on the plane indicated by the first axis and the second axis during the joining process, when the displacement data is indicated on the first axis and the load data is indicated on the second axis that intersects the first axis.

4. The solid-phase bonding apparatus according to claim 3, wherein the calculation device is configured to determine the bonding state between the first workpiece and the second workpiece based on the position of the vertex indicated by the trajectory.

5. The solid-phase bonding apparatus according to claim 3, wherein the calculation device is configured to determine the bonding state between the first workpiece and the second workpiece based on the position where the trajectory enters a predetermined region as the bonding process progresses.

6. The solid-phase bonding apparatus according to claim 3, wherein the calculation device is configured to determine the bonding state between the first workpiece and the second workpiece based on the position where the trajectory exits a predetermined area as the bonding process progresses.

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