Inspection process for resin products

Abstract

To provide an inspection process for a resin product to determine whether or not to move to a welding process after a melting process in which a resin member is heated by a hot plate.SOLUTION: An inspection process for a resin product includes: a melting process in which a mounting member joining surface 32 formed on a filler pipe mounting member 30 and a tank joining surface 12 formed on a periphery of an opening of a fuel tank 1, which has a larger volume than the filler pipe mounting member 30, are heated and melted in contact or non-contact using a hot plate; and a welding process to weld the tank joining surface 12 and the mounting member joining surface 32 after the melting process. The inspection process is located between the melting process and the welding process, and a temperature of at least the tank joining surface 12 after the melting process is measured by a camera 71 of a thermographic device 70 and analyzed by a control unit 72 to determine whether to proceed to the welding process.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an inspection process for determining whether or not to proceed to a welding process after a melting process in which a resin member is heated by a hot plate. [Background technology]

[0002] Hot plate welding is a welding method that uses a heated hot plate to heat and melt the joining interface of two resin parts in a contact or non-contact state, and then presses and joins them before the heated resin cools and hardens. Therefore, temperature control of the joining surface is extremely important.

[0003] For example, Patent Document 1 discloses a method in which, after heated and molten joining surfaces come into contact with each other through the relative movement of a gripping tool and begin to be pressed against each other, the approach displacement of the gripping tools over time, i.e., the deformation of the welded portion, varies depending on whether the joining surfaces are heated too much or too little, and in which the amount of heating is judged to be too much or too little, and therefore whether the welding is good or bad, from an approach displacement curve against the time axis.

[0004] Also, for example, Patent Document 2 discloses the following technique. As shown in Fig. 13, in a method for attaching a synthetic resin part 300 to an outer wall 200 of a synthetic resin hollow molded product 100 by welding the synthetic resin part 300, a welding surface 210 of the hollow molded product 100 and a welding surface 320 of the synthetic resin part 300 are heated and melted by a hot plate, and the hot plate for heating the synthetic resin part 300 presses the outer periphery of the heating surface that comes into contact with the synthetic resin part 300 so that melted burrs do not appear on the outer periphery of the melting surface of the synthetic resin part 300. a burr extrusion portion is formed, a hot plate is pressed against the welding surface 320 of the synthetic resin part 300, and the welding surface 320 is melted at the portion where the burr pressing portion contacts the welding surface 320 so that burr 340 does not appear on the outer peripheral end surface of the welding surface 320 of the synthetic resin part 300, and the welding surface 320 of the synthetic resin part 300 is pressed against the welding surface 210 of the hollow molded product 100, and the synthetic resin part 300 is welded such that burr 340 appears in a portion 350 of the welding surface 320 of the synthetic resin part 300 where burr 340 does not appear.

[0005] On the other hand, Patent Document 3 is an example of vibration welding rather than hot plate welding, and discloses a method for non-destructively inspecting the quality of the welding state of the welded portion 160 of the two resin members 110, 120 based on the temperature distribution, by vibrating the two resin members 110, 120 relatively while a rib 111 protruding from the first resin member 110 is abutted against the second resin member 120 as shown in FIG. 14, melting the rib 111 by frictional heat and welding the two resin members 110, 120 together to inspect the welding state of the resin product. The method involves capturing an image of the welded portion 160 of the two resin members 110, 120 immediately after welding with a camera 180 of a thermal image analyzer 170 such as a thermography device, and displaying the temperature distribution of the welded portion 160 on a monitor 190. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2002-28983 A [Patent Document 2] JP 2018-69701 A [Patent Document 3] JP 2000-238136 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the above Patent Document 1, it is not possible to judge whether the welding is done properly unless the two resin members are actually welded. In addition, in Patent Document 2, whether the welding is done properly is judged by observing the joint after welding using human eyes or a camera. Furthermore, in Patent Document 3, since vibration welding is used, the thermal image analysis by the thermography device is performed after welding. In other words, in all of the above technologies, the suitability of welding is judged after joining, so it is not possible to judge before the welding process, and it is not possible to prevent the implementation of an unnecessary welding process in a situation where welding is not suitable.

[0008] In hot plate welding, the amount of heat input to the joining surface, which is the heated surface of the resin part, fluctuates due to changes in the ambient temperature (room temperature), fluctuations in the power supply voltage for heating the hot plate, increases in the hot plate temperature due to the accumulated hot plate heating time, and variations in the distance between the hot plate surface and the joining surface of the resin part due to differences in the dimensions of the resin part, and this can cause insufficient heating of the joining surface, resulting in incomplete welding, so temperature control of the joining surface is extremely important. Therefore, there is a need to inspect the molten state of the joining surface before welding. [Means for solving the problem]

[0009] In order to solve the above problem, the present invention of claim 1 is an inspection process for a resin product, which includes a melting process in which a second resin member joining surface formed on a second resin member and a first resin member joining surface formed on the periphery of an opening of a first resin member having a larger volume than the second resin member are heated and melted in a contact or non-contact state using a hot plate, and a welding process in which the first resin member joining surface and the second resin member joining surface are welded together after the melting process, wherein the inspection process is arranged between the melting process and the welding process, and is characterized in that the temperature of at least the first resin member joining surface after the melting process is measured by a thermography device, the result is analyzed, and it is determined whether to proceed to the welding process.

[0010] In the present invention of claim 1, there is provided an inspection process for a resin product, which includes a melting process in which a second resin member joining surface formed on a second resin member and a first resin member joining surface formed on the periphery of an opening of a first resin member having a larger volume than the second resin member are heated and melted in a contact or non-contact state using a hot plate, and a welding process in which the first resin member joining surface and the second resin member joining surface are welded together after the melting process, in which the inspection process is arranged between the melting process and the welding process, and measures the temperature of at least the first resin member joining surface after the melting process using a thermography device, analyzes the result, and determines whether to proceed to the welding process. Therefore, if the temperature of the joining surface does not satisfy the temperature conditions required for welding, the transition to the welding process can be stopped, and unnecessary welding processes can be prevented from being performed and the outflow of resin products with incomplete welding can be prevented.

[0011] In addition, since the volume of the first resin member is larger than that of the second resin member, if the temperature of the first resin member joining surface satisfies the temperature conditions required for welding, the temperature of the second resin member joining surface formed on the second resin member, which has a smaller volume than the first resin member, satisfies the temperature conditions required for welding, so one camera in the thermography device is sufficient, and the inspection time can be shortened compared to the case where the temperature of the second resin member joining surface is also measured. Note that the temperature of the second resin member joining surface may be measured using one camera or a second camera. In that case, the temperatures of the first resin member joining surface and the second resin member joining surface after the melting process are measured by the thermography device, the results are analyzed, and it is determined whether to proceed to the welding process.

[0012] The present invention of claim 2 is an inspection process for resin products in which, in the invention of claim 1, the temperature of the joining surface of a first resin member measured by a thermography device is divided into a plurality of regions, and for each region, a first color indicating that a predetermined temperature has been reached and a second color indicating that the predetermined temperature has not been reached are displayed, and if the first color is displayed in all of the regions, a decision is made to proceed to the welding process, and if the second color is displayed in at least one of the regions, a decision is made not to proceed to the welding process.

[0013] In the present invention of claim 2, the temperature of the first resin member joining surface measured by the thermography device is displayed in a first color indicating that the specified temperature has been reached, and a second color indicating that the specified temperature has not been reached, making it easy and possible to determine whether or not to proceed to the welding process in a very short time.

[0014] Furthermore, the temperature of the first resin member joining surface measured by the thermography device is divided into multiple regions, and each region is displayed in a first color indicating that the specified temperature has been reached, and a second color indicating that the specified temperature has not been reached. Therefore, it is possible to provide feedback to temperature management of the hot plate, such as fluctuations in the power supply voltage for heating the hot plate and increases in the hot plate temperature due to accumulated hot plate heating time, particularly focusing on the areas displayed in the second color indicating that the specified temperature has not been reached.

[0015] If the first color is displayed in all of the regions, a decision is made to proceed to the welding process, and if the second color is displayed in at least one of the regions, a decision is made not to proceed to the welding process, thereby preventing unnecessary welding processes from being carried out and preventing the outflow of resin products with incomplete welding.

[0019] Claim 3 The present invention relates to claim 1 or Claim 2 In the invention, an identification number is assigned to the first resin member, and the identification number and the temperature of the joining surface of the first resin member measured with a thermography device are stored in pairs in an inspection process for resin products.

[0020] Claim 3 In the present invention, an identification number is assigned to the first resin member, and the identification number and the temperature of the joining surface of the first resin member measured by a thermography device are stored in pairs, improving traceability and enabling high quality control. Examples of the identification number include a QR code (registered trademark) and a bar code.

[0021] Claim 4 The present invention is as follows: 3 In the invention, the first resin member is a fuel tank for a vehicle, and the second resin member is an inspection process for a resin product which is at least one of a fuel system pipe mounting member, a sensor, and a cut-off valve.

[0022] Claim 4 In the present invention, the first resin member is a fuel tank for a vehicle, and the second resin member is at least one of a fuel system pipe mounting member, a sensor, and a cut-off valve. Therefore, by measuring, analyzing, and judging the temperature after melting of the joining surface of the first resin member formed around the opening edge of a large-volume plastic fuel tank using a thermography device, the ribs and flanges of the fuel system pipe mounting member, the sensor, and the cut-off valve can be securely attached to the fuel tank, and unnecessary welding processes can be prevented from being performed, and the leakage of a fuel tank with incomplete welding can be prevented in advance. Effect of the Invention

[0023] An inspection process for a resin product, comprising: a melting process in which a second resin member joining surface formed on a second resin member and a first resin member joining surface formed on the periphery of an opening of a first resin member having a larger volume than the second resin member are heated and melted in a contact or non-contact state using a hot plate; and a welding process in which the first resin member joining surface and the second resin member joining surface are welded together after the melting process, wherein the inspection process is arranged between the melting process and the welding process, and measures the temperature of at least the first resin member joining surface after the melting process using a thermography device, analyzes the result, and determines whether to proceed to the welding process. Therefore, if the temperature of the joining surface does not satisfy the temperature conditions required for welding, the transition to the welding process can be stopped, thereby preventing the implementation of an unnecessary welding process and preventing the outflow of a resin product with incomplete welding.

[0024] Furthermore, since the volume of the first resin member is larger than that of the second resin member, if the temperature of the joining surface of the first resin member satisfies the temperature conditions required for welding, then the temperature of the joining surface of the second resin member formed on the second resin member, which has a smaller volume than the first resin member, satisfies the temperature conditions required for welding. Therefore, only one camera in the thermography device is sufficient, and the inspection time can be shortened compared to the case where the temperature of the joining surface of the second resin member is also measured. [Brief description of the drawings]

[0025] [Figure 1] 1 is a cross-sectional view of a fuel tank according to an embodiment of the present invention. [Diagram 2] 2 is a schematic perspective view showing the positional relationship between a tank joint surface of the fuel tank, a filler pipe, and a camera unit according to the embodiment of the present invention. FIG. [Diagram 3] FIG. 2 is a plan view of the filler pipe mounting member side of the hot plate used in the embodiment of the present invention. [Figure 4] FIG. 2 is a front view of a hot plate used in an embodiment of the present invention. [Diagram 5] 1 is a front view showing a state in which a hot plate is inserted between a filler pipe mounting member and a tank joining surface before a melting process in an embodiment of the present invention. FIG. [Figure 6] FIG. 11 is a front view showing a state in which a filler pipe mounting member and a tank joint surface are in contact with a hot plate, illustrating a melting process in an embodiment of the present invention. [Figure 7] FIG. 11 is a front view showing a state after the melting process in the embodiment of the present invention, in which the joint surface between the filler pipe mounting member and the tank is separated from the hot plate. [Figure 8] FIG. 11 is a front view illustrating an inspection process in an embodiment of the present invention, illustrating temperature measurement of a tank joint surface by a camera of a thermography device. [Figure 9] FIG. 11 is a front view showing a state in which a filler pipe mounting member is pressed against a tank joining surface in a welding process according to an embodiment of the present invention. [Figure 10] 4 is a graph showing the relationship between time and temperature of a tank joining surface from a melting step to a welding step in an embodiment of the present invention. [Figure 11] 1 is a flowchart according to an embodiment of the present invention. [Figure 12] 6A and 6B are examples of observations of the temperature of the tank joint surface by a camera unit in an embodiment of the present invention, where (a) is an example of a case where it is judged as pass, and (b) is an example of a case where it is judged as fail. [Figure 13] FIG. 1 is an enlarged front view showing a state of a welding surface immediately before welding of a mounting member welding surface of a filler pipe mounting member to a tank welding surface of a tank mounting portion of a conventional fuel tank (Patent Document 2). [Figure 14] FIG. 1 is a diagram showing a conventional thermal image analysis device (Patent Document 3). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An embodiment of the present invention will be described with reference to a case where a filler pipe mounting member 30 serving as a second resin member is mounted on a tank outer wall 2 of a hollow fuel tank 1 which is a blow-molded product serving as a first resin member. The present invention can also be widely embodied in cases where a second resin member other than the filler pipe mounting member 30 is mounted on a first resin member other than the fuel tank 1.

[0027] The embodiment will be described with reference to Figures 1 to 12. The fuel tank 1 and filler pipe mounting member 30 used in this embodiment will be described with reference to Figures 1 and 2, the heating device with reference to Figures 3 and 4, the series of steps from melting, inspection and welding with reference to Figures 5 to 9 and 11, and the inspection process with reference to Figures 8, 10 and 12.

[0028] (Fuel Tank 1) As shown in Fig. 1, the fuel tank 1 is a hollow product formed by blow molding, and has a cross-sectional structure in which multiple layers that ensure rigidity and layers with low fuel permeability are laminated together. The multiple layers are composed of, for example, a central layer that is a barrier layer that prevents fuel permeation and is made of ethylene-vinyl alcohol copolymer (EVOH) or nylon, adhesive layers made of modified polyethylene above and below the barrier layer, and outer layers made of high density polyethylene (HDPE) on the outer surfaces of each of the adhesive layers.

[0029] A tank mounting portion 10 is provided on an upper portion of a tank outer wall 2 of the fuel tank 1. As shown in Fig. 2, the tank mounting portion 10 has a tank mounting hole 11 (opening) formed therein, and supplies fuel supplied from a filler pipe 20 (Fig. 1) into the fuel tank 1. The outer surface of the periphery of the tank mounting hole 11 is formed with a flat tank joint surface 12 which is a first resin member joint surface to which a filler pipe mounting member 30 (described later) is welded.

[0030] A breather pipe mounting member 7 is also formed on the upper part of the tank outer wall 2. A breather hose (not shown) is attached to the breather pipe mounting member 7 to release gas inside the fuel tank 1 outside the tank when refueling. The filler pipe mounting member 30 and the breather pipe mounting member 7 are referred to as fuel system pipe mounting members. Reference numeral 8 denotes a cut-off valve that prevents fuel leakage from the fuel tank 1 when the vehicle rolls over. Other sensors can also be attached, and the present invention can be used when the mounting members for the cut-off valve and sensors, such as ribs and flanges, are made of synthetic resin.

[0031] In addition, an identification number 9 based on a QR code (registered trademark) is attached to the upper part of the tank outer wall 2. Note that other identification numbers such as a bar code may also be used.

[0032] Another opening 6 is formed in the upper surface of the tank outer wall 2, and a sub-tank 5 is attached to the inner surface of the lower part of the tank outer wall 2 through the opening 6. The opening 6 is closed with a lid 60, and the lid 60 is screwed to the periphery of the opening 6 with a lock plate. A seal ring member is attached between the opening 6 and the lid 60 to seal the gap between the opening 6 and the lid 60.

[0033] (Filler pipe mounting member 30) 2, the filler pipe mounting member 30 has a pipe mounting portion 33 for mounting the filler pipe 20, a flange-shaped mounting member weld portion 31 formed at the tip of the pipe mounting portion 33, and a mounting member joint surface 32 that is melted by a hot plate (described later) is formed on the surface of the mounting member weld portion 31 that faces the tank outer wall 2 of the fuel tank 1. The filler pipe mounting member 30 is molded by blow molding or injection molding separately from the fuel tank 1. The material used is a thermoplastic synthetic resin that is resistant to fuel oil, and synthetic resins such as modified polyethylene, high density polyethylene (HDPE), polypropylene, polyacetal, and polyamide can be used, but a material that can be welded to the material that molds the fuel tank 1 is used.

[0034] (Heating device 40) 4, the heating device 40 has a tank-side hot plate 45 that heats and melts the tank joint surface 12 of the tank mounting portion 10 of the fuel tank 1, and a component-side hot plate 44 that heats and melts the mounting member joint surface 32 of the filler pipe mounting member 30. The component-side hot plate 44 and the tank-side hot plate 45 constitute a heating member 41.

[0035] The component-side hot plate 44 and the tank-side hot plate 45 are arranged above and below the plate-shaped hot plate holding member 42. As shown in Fig. 5, the hot plate holding member 42 is attached to a hot plate lifting member 43, which is lifted by an air cylinder 46. This allows the heating member 41 to be lifted. The hot plate holding member 42 is also rotatable in the horizontal direction relative to the hot plate lifting member 43 (Fig. 8).

[0036] As shown in Figures 3 and 4, two heaters 50 are inserted into the heating member 41. The heaters 50 heat the heating surfaces 44a, 45a to melt the mounting member joint surface 32 of the filler pipe mounting member 30 and the tank joint surface 12. In this embodiment, two heaters 50 are used, but the number can be changed appropriately depending on the size of the component side hot plate 44 and the tank side hot plate 45 and the heating temperature. Thermocouples 51 are installed symmetrically at 180 degrees to control the heating temperature by the heaters 50.

[0037] (Melting, inspection and welding) 5, a component holding member 47 for holding the filler pipe mounting member 30 is provided on the upper part of the component-side hot plate 44. The component holding member 47 is raised and lowered by an air cylinder 48. The filler pipe mounting member 30 is held by the component holding member 47, and is disposed above the tank mounting portion 10 of the tank outer wall 2 of the fuel tank 1 with a gap therebetween.

[0038] After that, the heating member 41 is inserted between the tank mounting part 10 and the filler pipe mounting member 30. At this time, the heating member 41 is not in contact with the tank mounting part 10 and the filler pipe mounting member 30, but the component side hot plate 44 of the heating member 41 is positioned so as to face the mounting member joining surface 32 of the filler pipe mounting member 30, and the tank side hot plate 45 of the heating member 41 is positioned so as to face the tank joining surface 12 of the tank mounting part 10 of the tank outer wall 2 of the fuel tank 1.

[0039] Next, as shown in Fig. 6, the hot plate lifting member 43 is operated by the air cylinder 46 to lower the hot plate holding member 42, so that the tank side hot plate 45 comes into contact with the tank joint surface 12 of the tank mounting part 10. Furthermore, the component holding member 47 is lowered by the air cylinder 48 to bring the mounting member joint surface 32 of the filler pipe mounting member 30 into contact with the component side hot plate 44. Then, the tank joint surface 12 of the tank mounting part 10 and the mounting member joint surface 32 of the filler pipe mounting member 30 are melted. Note that a gap may be formed between the component side hot plate 44 of the heating member 41 and the mounting member joint surface 32 of the filler pipe mounting member 30, and between the tank side hot plate 45 of the heating member 41 and the tank joint surface 12 of the tank mounting part 10, so that the mounting member joint surface 32 of the filler pipe mounting member 30 and the tank joint surface 12 of the tank mounting part 10 are melted in a non-contact state.

[0040] 7, the component holding member 47 is raised by the air cylinder 48 to separate the mounting member joint surface 32 of the filler pipe mounting member 30 from the component-side hot plate 44. Furthermore, the hot plate lifting member 43 is operated by the air cylinder 46 to raise the hot plate holding member 42 and separate the tank-side hot plate 45 from the tank joint surface 12 of the tank mounting part 10.

[0041] Next, as shown in FIG. 8, the hot plate holding member 42 is rotated horizontally relative to the hot plate lifting member 43 so that the heating member 41 is removed from between the mounting member joint surface 32 of the filler pipe mounting member 30 and the tank joint surface 12 of the tank mounting portion 10.

[0042] At this time, the camera 71 of the thermography device 70 is set in advance at an angle α of about 60° with respect to the tank joint surface 12 of the tank mounting part 10, at a position about 30 cm to about 60 cm from the center O, and focused on the tank joint surface 12, so that it is possible to observe the temperature distribution of the tank joint surface 12. The inspection process using the thermography device 70 will be described in detail later.

[0043] When it is determined based on the temperature distribution observation of the tank joint surface 12 by the thermography device 70 that it is permitted to proceed to the next welding process, the filler pipe attachment member 30 held by the component holder 47 is lowered by the air cylinder 48 and pressed against the tank joint surface 12 of the tank mounting part 10 for welding, as shown in Fig. 9. Finally, the component holder 47 is raised by the air cylinder 48.

[0044] (Inspection process) As shown in Fig. 8, a thermography device 70 used in the inspection process has a camera 71 and a control unit 72. The control unit 72 also has a thermal analysis unit, a judgment unit, and a storage unit. The camera 71 uses infrared rays to observe the temperature distribution on the tank joint surface 12. Note that an identification number 9 based on a QR code (registered trademark) affixed to the upper part of the tank outer wall 2 has been read in advance by a QR code (registered trademark) reader (not shown).

[0045] 12(a) and (b), in the thermal analysis section of the control section 72 of the thermography device 70, the tank joint surface 12 is divided into eight regions, and each region is displayed in a first color, for example, blue, which indicates that a predetermined temperature has been reached, and a second color, for example, red, which indicates that the predetermined temperature has not been reached. Note that the number of divisions is not limited to eight.

[0046] Then, when the first color is displayed in all of the eight observed regions as shown in Fig. 12(a), a judgment section of the control section 72 of the thermography device 70 decides to proceed to the welding process shown in Fig. 9, and issues a signal to lower the air cylinder 48. On the other hand, when the second color is displayed in at least one of the eight regions as shown in Fig. 12(b) (X in region P8 in Fig. 12(b)), the judgment section issues a signal to stop the device in the state shown in Fig. 8, and notifies the occurrence of an abnormality in the equipment by, for example, activating a red rotating lamp in the equipment or issuing a color or sound alarm signal on the equipment operation monitoring system.

[0047] Furthermore, in the storage section of the control section 72 of the thermography device 70, the results of the thermal analysis section and the determination section, the identification number 9 and information on the heating device 40 are stored in association with each other.

[0048] 7 to 9, the mounting member joint surface 32 of the filler pipe mounting member 30 moves away from the component side hot plate 44, and further, the hot plate lifting member 43 is operated by the air cylinder 46 to raise the hot plate holding member 42, and the tank side hot plate 45 moves away from the tank joint surface 12 of the tank mounting part 10. Therefore, the surface temperatures of the tank joint surface 12 of the tank mounting part 10 and the mounting member joint surface 32 of the filler pipe mounting member 30 decrease by the amount corresponding to the inspection process, compared to the conventional case.

[0049] Fig. 10 is a graph showing the relationship between time and surface temperature of the tank joint surface 12 during the period from the melting step to the welding step for determining whether or not the tank can proceed to the predetermined welding step, and T1 shown by the broken line indicates the lowest temperature at which welding is possible. Note that T2 is the temperature at the time of melting. Region A represents the melting step in Fig. 6, region B represents the rising time of the heating member 41 in Fig. 7, region C represents the inspection step in Fig. 8, region D represents the lowering time of the mounting member joint surface 32 of the filler pipe mounting member 30 by the air cylinder 48, and region E represents the pressing of the mounting member joint surface 32 of the filler pipe mounting member 30 against the tank joint surface 12 in Fig. 9, i.e., the welding step.

[0050] Therefore, if the temperatures of all areas are equal to or higher than line L at a given time in area C, it is determined that transition to welding is possible. The temperatures and times in Fig. 10 vary depending on the material and welding equipment, but the times are t1 about 1 second, t2 about 3 seconds, and t3 about 5 seconds.

[0051] Fig. 11 is a flow chart that simply summarizes the flow up to this point. By inserting the inspection process of the present invention between the melting process and the welding process, it is possible to reliably weld the mounting member joint surface 32 of the filler pipe mounting member 30 to the tank joint surface 12 of the tank mounting part 10 over the entire circumference. Also, if the temperature of the tank joint surface 12 does not satisfy the predetermined temperature conditions required for welding, it is possible to stop the transition to the welding process, thereby preventing the implementation of unnecessary welding processes.

[0052] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the object of the present invention.

[0053] For example, in the above embodiment, the camera 71 is set at an angle α of about 60° with respect to the tank joint surface 12 of the tank mounting part 10, but it can be set within a range of 45° to 90° so as not to interfere with equipment. An angle α smaller than 45° is undesirable because it distorts the image and makes it difficult to focus on the entire tank joint surface 12 of the tank mounting part 10. Note that when the angle α is increased, the travel distance of the air cylinders 46, 48 becomes longer, and particularly when the angle α approaches 90°, it is necessary to increase the travel distance of the air cylinders 46, 48 and move the camera 71 onto the center O.

[0054] For example, in the above embodiment, a determination was made for each region based on whether or not the temperature in region C reached a temperature equal to or higher than line L at a predetermined time, but depending on changes in the ambient temperature (room temperature), the degree of temperature change (temperature drop) in region C in Fig. 10 may be greater than line L. In that case, the thermal analysis section of thermography device 70 may also observe temperature changes over a certain period of time, and based on the state of the temperature change, the determination section may determine that transition to the welding process is not possible even if the temperature in region C has reached a temperature equal to or higher than line L, and control may be added to stop the device. [Explanation of symbols]

[0055] 10 Tank mounting portion (first resin member) 12 Tank joint surface (first resin member joint surface) 30 Filler pipe mounting portion (second resin member) 32 Mounting portion joint surface (second resin member joint surface) 40 Heating device 44 Component side heating plate 45 Tank side hot plate 70 Thermography Equipment 71 Camera 72 Control section

Claims

1. A second resin member bonding surface formed on the second resin member and a first resin member bonding surface formed on a periphery of an opening of a first resin member having a volume larger than that of the second resin member, A melting step of heating and melting the material in a contact or non-contact state using a hot plate; An inspection process for a resin product including a welding process of welding the first resin member joining surface and the second resin member joining surface after the melting process, The inspection step is arranged between the melting step and the welding step, An inspection process for a resin product, characterized in that at least the temperature of the joining surface of the first resin member after the melting process is measured by a thermography device, the result is analyzed, and it is determined whether or not to proceed to the welding process.

2. The temperature of the first resin member joining surface measured by the thermography device is divided into a plurality of regions, and each region is displayed in a first color indicating that a predetermined temperature has been reached and a second color indicating that the predetermined temperature has not been reached, 2. An inspection process for resin products as described in claim 1, wherein if the first color is displayed in all of the regions, a decision is made to proceed to the welding process, and if the second color is displayed in at least one of the regions, a decision is made not to proceed to the welding process.

3. The inspection process for resin products according to claim 1 or claim 2, wherein an identification number is assigned to the first resin member, and the identification number and the temperature of the joining surface of the first resin member measured by the thermography device are stored in pairs.

4. 4. An inspection process for a resin product according to claim 1, wherein the first resin member is a fuel tank for a vehicle, and the second resin member is at least one of a fuel system pipe mounting member, a sensor, and a cut-off valve.

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