Patent Publication Number: US-2021162681-A1

Title: Bonding System and Bonding Method

Description:
TECHNICAL FIELD 
     The present disclosure relates to a bonding system and a bonding method. 
     BACKGROUND ART 
     Technologies relating to the bonding of resin materials are disclosed in Japanese Unexamined Patent Application Laid-Open (JP-A) Nos. 2015-093482 and 2015-120335, and in Japanese Patent No. 5687801. 
     Because the aforementioned technologies provide unidirectional bonding, they enable planar shapes such as test pieces and the like to be bonded together. However, they make no mention of bonding and manufacturing involving resin articles that have 3-dimensional configurations and therefore require multidirectional bonding (for example, large-sized resin parts for automobiles). 
     In addition, technologies that utilize an adhesive agent to bond together large-sized resin parts for automobiles that have 3-dimensional configurations also exist. However, because of the cost of the adhesive agent and the jig occupation time until curing is completed, such methods cannot be said to increase productivity. 
     Bonding equipment that may be hypothesized from the known technology includes a C-gun type bonding device  200  (see  FIG. 8 ) that provides two-sided access, however, such equipment would have the following drawbacks. 
     In other words, a C-gun type of bonding device provides poor tool accessibility, and it is difficult to bond central portions of articles having a so-called ‘deep belly’ using such a bonding device. In addition, bonding onto undercut-shaped portions is not possible, so that there are many limitations on the type of shapes that can be bonded. In order to deal with portions such as these, preprocessing is performed such as forming a hole in the parts, and then punching a blind rivet into each fastening point. As a consequence, increases in processing costs and processing time are unavoidable. Moreover, because a C-gun is used, an articulated robot  30  capable of transporting a heavy payload is necessary, so that a sizable amount of capital investment is needed. In addition, it may also be assumed that the speed of transporting will also be slow. 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     The present disclosure was conceived in view of the above-described circumstances and provides a bonding system and a bonding method that provide superior productivity when parts formed from a thermoplastic resin material are bonded together via welding. 
     Solution to the Problem 
     A bonding system according to a first aspect of the present disclosure includes a supporting jig having a mounting surface on which bonding substrates are mounted, a bonding device that sandwiches and welds the bonding substrates between the bonding device and the mounting surface, an articulated robot to which the bonding device is attached, and a control unit that controls the articulated robot and the bonding device. 
     In the bonding system according to the first aspect of the present disclosure, bonding substrates are mounted on a mounting surface of a supporting jig. Moreover, a bonding device that sandwiches the bonding substrates between the bonding device and the mounting surface and that welds the bonding substrates is attached to an articulated robot  30 . In addition, the articulated robot and the bonding device are controlled by a control unit. As a result of these components being operated, bonding substrates  90  are bonded. Because of this, the bonding device is able to access the bonding substrates from one side thereof, and perform a bonding operation on the bonding substrates. Accordingly, productivity is improved. 
     A bonding system according a second aspect of the present disclosure is characterized in that, in the bonding system according to the first aspect, the mounting surface is formed so as to include a plurality of bonding supporting surfaces, and the control unit controls the articulated robot and the bonding device such that the bonding substrates are welded on the plurality of bonding supporting surfaces. 
     A bonding system according a third aspect of the present disclosure is characterized in that, in the bonding system according to the first aspect, there is further provided a temperature adjustment device that adjusts a temperature of the mounting surface. 
     A bonding system according a fourth aspect of the present disclosure is characterized in that, in the bonding system according to the first aspect, the mounting surface is formed so as to include a plurality of bonding supporting surfaces, and there is further provided a temperature adjustment device that adjusts a temperature of the plurality of bonding supporting surfaces. 
     A bonding system according a fifth aspect of the present disclosure is characterized in that, in the bonding system according to any one of the first though fourth aspects, there is further provided an operating device that operates the supporting jig. 
     A bonding method according a sixth aspect of the present disclosure is a bonding method in which bonding substrates ,which include a thermoplastic resin material, are bonded using a bonding system provided with a supporting jig having a mounting surface on which bonding substrates are mounted, a bonding device that sandwiches and welds the bonding substrates between the bonding device and the mounting surface, an articulated robot to which the bonding device is attached, and a control unit that controls the articulated robot and the bonding device. 
     A bonding method according to a seventh aspect of the present disclosure is characterized in that, in the bonding method according to the sixth aspect, the mounting surface is formed so as to include a plurality of bonding supporting surfaces, and the control unit controls the articulated robot and the bonding device such that the bonding substrates are welded on the plurality of bonding supporting surfaces. 
     A bonding method according to an eighth aspect of the present disclosure is characterized in that, in the bonding method according to the sixth aspect, the bonding system is further provided with a temperature adjustment device that adjusts a temperature of the mounting surface. 
     A bonding method according to a ninth aspect of the present disclosure is characterized in that, in the bonding method according to the sixth aspect, the mounting surface is formed so as to include a plurality of bonding supporting surfaces, and the bonding system is further provided with a temperature adjustment device that adjusts a temperature of the plurality of bonding supporting surfaces. 
     A bonding method according to a tenth aspect of the present disclosure is characterized in that, in the bonding method according to any of the sixth through ninth aspects, the bonding system is further provided with an operating device that operates the supporting jig. 
     Advantageous Effects of the Invention 
     As has been described above, the bonding system and bonding method according to the present disclosure have the excellent effect that they provide superior productivity when articles formed from a thermoplastic resin material are bonded together via welding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an enlarged cross-sectional view showing a supporting jig  10  in a bonding system of the present exemplary embodiment. 
         FIG. 1B  is an enlarged cross-sectional view showing a state in which bonding substrates are bonded using the bonding system of the present exemplary embodiment. 
         FIG. 2  is a view showing the overall structure of the bonding system of the present exemplary embodiment. 
         FIG. 3  is a cross-sectional view showing an operating device of the present exemplary embodiment. 
         FIG. 4  is an enlarged view showing the bonding device of the present exemplary embodiment. 
         FIG. 5  is an enlarged view showing another aspect of the bonding device of the present exemplary embodiment, namely, a bonding device used in electromagnetic induction heat welding. 
         FIG. 6  is a schematic diagram showing a state in which a conductivity imparting component is sandwiched between bonding substrates  90 . 
         FIG. 7  is a view showing a relationship between a supporting jig and a plurality of bonding substrates. 
         FIG. 8  is a view showing a C-gun type of bonding device of the conventional technology. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Hereinafter, a bonding system S and a bonding method according to an exemplary embodiment of the present disclosure will be described with reference to  FIG. 1A  through  FIG. 7 . 
     The overall structure of the bonding system S of the present exemplary embodiment is shown in  FIG. 2 . As is shown in  FIG. 2 , the bonding system S of the present exemplary embodiment is provided with an articulated robot  30 , a bonding device  20 , a supporting jig  10 , an operating device  50 , and a control unit  40 . 
     Note that thermoplastic resin materials are included as the bonding substrates  90  that are to be bonded by the bonding system S. In other words, the bonding that is performed may be, for example, a bonding together of bonding substrates  90  that are each formed from thermoplastic resin materials, or a bonding together of a bonding substrate formed from a thermoplastic resin material and a bonding substrate formed from a metal material. Examples of the resin material include fiber reinforced resins such as carbon fiber reinforced resins and glass fiber reinforced resins, and also resins other than these. 
     (Articulated Robot  30 ) 
     The articulated robot  30  is a vertically articulated robot that is provided with articulated joints. The number of axes of the articulated robot  30  is, for example, from 4 to 7 axes, however, a different number of axes may also be employed. The bonding device  20  is attached to a wrist portion of the articulated robot  30 . The articulated robot  30  is constructed so as to be able to bear the weight of the bonding device  20 , and to withstand the load generated during bonding. 
     (Bonding Device  20 ) 
     The bonding device  20  is a device that sandwiches bonding substrates  90  between itself and the supporting jig  10 , and bonds the bonding substrates  90  together by welding (see  FIG. 1A  and  FIG. 1B ). The bonding method used by the bonding device  20  is desirably a surface direct pressure bonding method which is applied to the bonding substrates  90 , and it is desirable that, for example, ultrasonic welding and electromagnetic induction heat welding be performed. 
     Note that because the direction of excitation when vibration welding is performed is limited to a single direction, this method cannot be used to bond together bonding substrates  90  whose bonding surfaces have a two-dimensional or greater configuration. In addition, there are also a large number of layout restrictions in articles having a unidirectional structure such as in the amplitude portion and in providing part clearance and the like, so that this method is not suitable for these articles as well. Accordingly, the term ‘bonding device’ of the present disclosure does not include devices that perform vibration welding. 
     A structure employed when the bonding method of the bonding device  20  is an ultrasonic welding method is shown in  FIG. 4 . As is shown in  FIG. 4 , bonding substrates  90  that are formed from thermoplastic resin are bonded together via fusing by ultrasonic vibration provided by a distal end portion  22  (i.e., a horn) of the bonding device  20  and welding pressure P. 
     In addition, a structure employed when the bonding method of the bonding device  20  is an electromagnetic induction heat welding method is shown in  FIG. 5 . As is shown in  FIG. 5 , a bonding substrate  90  that has electrical conductivity (here, for example, a substrate  96  that is formed from a metal material) is heated as a result of an induction current being generated by supplying a high-frequency current to a coil  26 , and consequently melts a substrate  92  that is formed from a thermoplastic resin material. The substrate  92  and the substrate  96  are then bonded together by welding pressure P applied by a roller  28 . Note that it is also possible for the vertical relationship between the metal material substrate  96  and the resin material substrate  92  to be inverted. 
     When the bonding method of the bonding device  20  is an electromagnetic induction heat welding method and the bonding substrates  90  that are to be bonded together are formed solely by resin materials having no electrical conductivity, then as is shown in  FIG. 6 , a conductivity imparting component  80  such as a conductive filler or metal mesh or the like is interposed between the bonding substrates  90  thereby enabling these to be bonded together. 
     (Supporting Jig  10 ) 
     The supporting jig  10  is provided with a mounting surface  12  on which the bonding substrates  90  are mounted (i.e., set). As is shown in  FIG. 1B , the bonding substrates  90  are mounted on the mounting surface  12 , and once the bonding substrates  90  (i.e.,  92  and  96 ) have been sandwiched between the mounting surface  12  and the distal end portion  22  (i.e., the horn) of the bonding device  20 , they are bonded together. In this way, the bonding device  20  is able to access the bonding substrates  90  from one side thereof, and consequently bond the bonding substrates  90  together. 
     As is shown in  FIG. 4 , a load sensor, a distal end position control device, and a thermal camera  24  are provided in the bonding device  20 . The load sensor detects the pressure P that is applied by the distal end portion  22  to the bonding substrates  90 . The distal end position control device controls the position (see an arrow D) of the distal end of the device. The thermal camera  24  measures the surface temperature of the bonding substrates  90 . 
     As is shown in  FIG. 1A  and  FIG. 1B , temperature sensors  62  such as thermocouples are built into the supporting jig  10 . The temperature sensors  62  detect the temperature of the supporting jig  10 . The temperature sensors  62  are respectively provided so as to correspond to portions of the supporting jig  10  where the bonding is performed, namely, in the respective bonding supporting surfaces  15  ( 15 A,  15 B,  15 C; see  FIG. 1A ). As a result, the temperatures of each of the bonding supporting surfaces  15  can be detected. 
     As has been described above, because a structure is employed in which the temperature of each portion can be measured, the bonding device  20  can be controlled such that the bonding substrates  90  are adequately melted together, and such that a high bond quality can be guaranteed. 
     (Temperature Adjustment Devices  64 ) 
     Temperature adjustment devices  64  are also provided in the supporting jig  10 . The temperature adjustment devices  64  are devices that adjust the temperature of the supporting jig  10 . 
     Various types of structure may be considered for the temperature adjustment devices  64 , however, in the present exemplary embodiment, a circuit is formed within the supporting jig  10  and a medium is made to flow along this circuit. The supporting jig  10  can be heated by supplying a heating medium to the circuit, and the supporting jig  10  can be cooled by supplying a cooling medium to the circuit. Examples of the medium supplied to the circuit include water, oil, and air and the like. Note that the temperature adjustment devices  64  may also be formed by a cartridge heater that is embedded within the supporting jig  10 . 
     As is shown in  FIG. 1A  and  FIG. 1B , a temperature adjustment device  64  is provided so as to correspond to each of the bond supporting surfaces  15  ( 15 A,  15 B,  15 C), and is formed so as to be able to adjust the respective temperature of each individual bonding supporting surface  15  ( 15 A,  15 B,  15 C). 
     (Operating Device  50 ) 
     The operating device  50  is a device that operates rotations and the like of the supporting jig  10 . The operating device  50  is controlled so as to move in conjunction (i.e., in coordination) with the articulated robot  30 . As a result, the reach of the articulated robot  30  is compensated and a reduction in bonding time can be achieved. 
     In the present exemplary embodiment, as is shown in  FIG. 3 , a turning bearing  54  is provided between a stand  52  and the supporting jig  10 . As a consequence, the supporting jig  10  is able to be rotated around an axis P that extends in an up-down direction. In addition, a spring-loaded ball roller  56  is provided in a portion located at a distance from the axis P forming the center of rotation. As a result, the supporting jig  10  is able to resist moment and deflection during rotation. 
     (Control Unit  40 ) 
     The control unit  40  is connected to the articulated robot  30 , the bonding device  20 , the operating device  50 , and the temperature adjustment device  64 , and controls each of the articulated robot  30 , bonding device  20 , operating device  50 , and temperature adjustment device  64 . 
     For example, the control unit  40  controls the bonding device  20  based on the surface temperature of the bonding substrates  90  detected by the thermal camera  24 , and on the temperature of the supporting jig  10  detected by the temperature sensors  62 . Additionally, the control unit  40  also controls the bonding device  20  based on the pressure P applied to the bonding substrates  90  detected by the load sensor. As a result, the weld quality can be stabilized. 
     Moreover, for example, the bonding supporting surfaces  15  are heated prior to welding as a result of the control unit  40  controlling the temperature adjustment device  64 . As a consequence, the bonding substrates  90  that are in contact with the bonding supporting surface  15  are heated, so that the molten state of the bonding substrates  90  is either accelerated, or the molten state thereof is maintained. 
     Additionally, the control unit  40  also cools the bonding supporting surface  15  after welding. As a consequence, the bonding substrates  90  that are in contact with the bonding supporting surface  15  are cooled, so that any thermal effects on portions that are adjacent to the portions being bonded are inhibited. Accordingly, the weld quality can be stabilized and improved. 
     (Specific Structure of the Supporting Jig) 
     An example of the configuration of the supporting jig  10  is shown in  FIG. 1A . As is shown in  FIG. 1A , the mounting surface  12  is not formed as a simple flat surface, but is instead formed having a three-dimensional configuration. 
     More specifically, the mounting surface  12  is formed so as to include a first horizontal surface  12 A whose normal direction faces upwards. A first inclined surface  12 B is formed extending diagonally upwards from an end portion of the first horizontal surface  12 A. A normal direction of the first inclined surface  12 B faces diagonally upwards (i.e., in a diagonally upward direction towards the upper-right side in  FIG. 1A ). A second horizontal surface  12 C is formed extending from an upper end of the first inclined surface  12 B. A second inclined surface  12 D whose normal direction faces diagonally downwards is formed extending from an end portion (i.e., the left end in  FIG. 1A ) of the second horizontal surface  12 C, and a third horizontal surface  12 F is formed via a vertical surface  12 E extending from an upper end of the second inclined surface  12 D. 
     The bonding steps are performed at each of the first horizontal surface  12 A, the first inclined surface  12 B, and the third horizontal surface  12 F. 
     More specifically, firstly, the first bonding substrate  92  and the second bonding substrate  94  are welded together at the first inclined surface  12 B. The portion on the first inclined surface  12 B where bonding is performed is referred to specifically as a first bonding supporting surface  15 A (see  FIG. 1A ). 
     Next, the first bonding substrate  92  and the third bonding substrate  96  are welded together at the third horizontal surface  12 F. The portion on the third horizontal surface  12 F where bonding is performed is referred to specifically as a second bonding supporting surface  15 B. 
     Lastly, the first bonding substrate  92  and the third bonding substrate  96  are welded together at the first horizontal surface  12 A. The portion on the first horizontal surface  12 A where bonding is performed is referred to specifically as a third bonding supporting surface  15 C. 
     In other words, the order in which bonding is performed is, firstly, at the first bonding supporting surface  15 A, secondly, at the second bonding supporting surface  15 B, and lastly, at the third bonding supporting surface  15 C. When the bonding at the first bonding supporting surface  15 A is performed, the first bonding substrate  92  and the second bonding substrate  94  are mounted on the supporting jig  10 , while the third bonding substrate  96  is left off the supporting jig  10 . After the bonding at the first bonding surface  15 A has been completed, as is shown in  FIG. 1B , the third bonding substrate  96  is then mounted on the supporting jig  10  and the remaining bonding is performed. Note that, if necessary, the bonding can be performed with the bonding substrates  90  fixed in position by means of a clamp  70  or the like (see  FIG. 1B ). 
     The cross-sectional structure shown in  FIG. 1B  extends in a perpendicular direction relative to the paper surface while the shape of this cross-sectional structure is maintained. Consequently, a closed cross-sectional structure extending in a perpendicular direction relative to the paper surface is formed by the first bonding substrate  92 , the second bonding substrate  94 , and the third bonding substrate  96 . 
     Accordingly, each bonding portion is bonded either continuously or intermittently in the direction in which each bonding portion extends (i.e., in a perpendicular direction relative to the paper surface). If, for example, the bonding method is an ultrasonic welding method, then the distal end portion  22  of the bonding device  20  is abutted against the bonding portions intermittently in the direction in which each bonding portion extends, and bonding is performed. 
     Note that a procedure for manufacturing a resin frame of an automobile using the bonding system of the present disclosure is shown schematically in  FIG. 7 . In this manner, according to the bonding system of the present disclosure, it is possible to bond together a plurality of bonding substrates  90  using the single supporting jig  10 , and accordingly improve productivity. 
     [Action and Effects] 
     Next, actions and effects of the bonding system of the present exemplary embodiment will be described. 
     In the bonding system S according to the present exemplary embodiment, bonding substrates  90  are mounted on the mounting surface  12  of the supporting jig  10 . The bonding device  20  that sandwiches the bonding substrates  90  between itself and the mounting surface  12  and then welds the bonding substrates  90  together is attached to the articulated robot  30 . The articulated robot  30  and the bonding device  20  are then controlled by the control unit  40  such that the bonding substrates  90  are welded together. 
     As a result, the bonding device  20  is able to access the bonding substrates  90  from one side thereof, and bond the bonding substrates  90  together. 
     Furthermore, compared with a structure in which, for example, a C-gun type of device is attached to an articulated robot and used to perform bonding, an articulated robot having a lighter transportable payload can be used so that capital investment costs can also be reduced. Moreover, because the bonding device of the present exemplary embodiment is more compact than a C-gun type, the operating speed thereof can also be increased. 
     Moreover, because of this, tool accessibility is improved so that center portions of large-sized components such as ‘deep belly portions’ like that shown in  FIG. 1B  can also be easily bonded. 
     Moreover, in the bonding system S of the present exemplary embodiment, the mounting surface  12  is formed so as to include a plurality of bonding supporting surfaces  15  ( 15 A,  15 B,  15 ) that each have a different normal direction. In addition, the control unit  40  controls the articulated robot  30  and the bonding device  20  such that the bonding substrates  90  are welded at the plurality of bonding supporting surfaces  15  ( 15 A,  15 B,  15 ). 
     Because of this, using a single supporting jig  10 , it is possible to bond together bonding substrates (i.e., resin parts) that require multidirectional bonding. Accordingly, tooling setup changes in the supporting jig  10  can be reduced. 
     Moreover, the bonding system S of the present exemplary embodiment is also provided with the temperature adjustment device  64  that adjusts the temperature of the bonding supporting surface  15 . Because of this, by adjusting the temperature of the bonding supporting surfaces  15  via the temperature adjustment device  64 , it is possible to both stabilize and improve the weld quality. In particular, by heating the bonding substrates  90  prior to welding, the resin molten state thereof is either accelerated, or maintained. 
     Moreover, by cooling the welded portion after welding has been completed, any effects from the heat thereof on adjacent portions can be eliminated. Accordingly, a further stabilization and improvement in the weld quality can be anticipated. 
     Additionally, by providing the temperature adjustment device  64 , when a bonding method that is used in combination with a thermosetting adhesive agent is employed, an acceleration of the curing of the adhesive agent is possible, and a shortening in the cycle time can be achieved. 
     Moreover, in the bonding system S of the present exemplary embodiment, the bonding device  20  is formed such that the distal end portion  22  thereof is replaceable. Because of this, by replacing the distal end portion  22  to match the shape of the bonding portion, limitations on the range of movement and on the singular configuration of the articulated robot  30  can be avoided, and the range of a single bonding operation performed on the supporting jig can be set to a broader range. In addition, tooling setup changes in the supporting jig  10  can be reduced. 
     Moreover, in the bonding system S of the present exemplary embodiment, the material used to form the supporting jig  10  is an aluminum alloy. Because of this, the supporting jig  10  is highly efficient in discharging heat generated during bonding. 
     Moreover, in the bonding system S of the present exemplary embodiment, the operating device  50  is also provided in the supporting jig  10 . Because of this, limitations on the range of movement of the articulated robot  30  and limitations on the singular configuration of the articulated robot  30  can be avoided, and the range of a single bonding operation performed on the supporting jig can be set to a broader range. In addition, tooling setup changes in the supporting jig  10  can be reduced, and both a reduction in takt time and the bonding of a plurality of articles can be achieved in a single step. 
     Moreover, in the bonding system S of the present exemplary embodiment, a pressure detection sensor is also mounted in the bonding device  20 . Because of this, it is possible to measure the pressure applied to the bonding substrates  90 . The bonding device  20  can then be controlled based on the obtained measurement results. Accordingly, not only can the weld quality be stabilized, but better quality control can also be achieved. 
     Moreover, in the bonding system S of the present exemplary embodiment, a thermal camera is also mounted in the bonding device  20 . Because of this, it is possible to measure the surface temperature of the bonding substrates  90 . In addition, the temperature sensors  62  are built into the supporting jig  10 . As a result, the control unit  40  controls the bonding device  20  based on the obtained measurement results. Accordingly, not only can the weld quality be stabilized, but better quality control can also be achieved. 
     (Supplementary Description of the Above-Described Exemplary Embodiment) 
     Note that, in the above-described exemplary embodiment, the bonding system S is provided with the operating device  50 , however, the present disclosure is not limited to this, and it is also possible for no operating device to be provided. 
     Moreover, in the above-described exemplary embodiment, the bonding system S is provided with the temperature adjustment devices  64 , however, the present disclosure is not limited to this, and it is also possible for no temperature adjustment devices to be provided. 
     Moreover, in the above-described exemplary embodiment, an example is described in which the material used to form the supporting jig  10  is an aluminum alloy, however, the present disclosure is not limited to this, and it is also possible for another material to be used to form the supporting jig. 
     Moreover, in the above-described exemplary embodiment, an example in which the mounting surface  12  of the supporting jig  10  is formed so as to include a plurality of bonding supporting surfaces  15  ( 15 A,  15 B,  15 C) that each have a different normal direction, however, the ‘plurality of bonding supporting surfaces’ of the present disclosure are not limited to these. In other words, it is not essential that the plurality of bonding supporting surfaces be bonding supporting surfaces that each have a different normal direction, and may instead be a plurality of bonding supporting surfaces that each have the same normal direction. 
     Priority is claimed on Japanese Patent Application No. 2017-065548, the disclosure of which is incorporated herein by reference 
     All references, patent applications and technical specifications cited in the present specification are incorporated by reference into the present specification to the same extent as if the individual references, patent applications and technical specifications were specifically and individually recited as being incorporated by reference.