Method and apparatus for manufacturing laminate

Abstract

To simultaneously, uniformly and firmly bond a main member and first and second sub-members different in shape from each other.SOLUTION: The laminate manufacturing apparatus 1 includes the opposing electrodes 2122 and to which high-frequency power is supplied, and the workpiece pressurizing drive unit 63 that pressurizes the substrate 41 and the plurality of packings 421422 and having different shapes laminated at different positions of the substrate 41 via the adhesive Pa between the opposing electrodes 2122 and, and one electrode 22 of the opposing electrodes 2122 and is divided into the plurality of split electrodes 221222 and so as to face the plurality of packings 421422 and. The split electrode 221,222 uniformly distributes and supplies the high-frequency power according to the size of the facing packing 421,422 by the metal plate 220.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a laminate manufacturing method and apparatus for bonding a plurality of sub-members to a main member by dielectrically heating an adhesive. [Background technology]

[0002] Conventionally, devices have been proposed for manufacturing structural materials by applying adhesive between and stacking multiple wooden planks or the like, applying high-frequency power, and bonding them using dielectric heating (e.g., Patent Documents 1 to 3). Patent Document 1 describes a panel manufacturing device that laminates planar materials together using adhesive and then pressurizes and bonds them while irradiating high-frequency waves. Patent Document 2 describes a laminated veneer lumber manufacturing device that applies adhesive to veneers and bonds them using high-frequency dielectric heating. Patent Document 3 describes a panel manufacturing device that bonds a frame and a face material covering one or both sides by applying a thermosetting adhesive to the contact points between them and supplying high-frequency power to a grid electrode. Thus, currently, known technologies use dielectric heating to bond stacked planar materials of the same shape, heat the adhesive layer between a frame and a panel on its front side to harden and bond them, or melt the resin material itself to bond them. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2000-37779 [Patent Document 2] Patent Publication No. 6-206205 [Patent Document 3] Patent Publication No. 59-16750 Summary of the Invention [Problem to be solved by the invention]

[0004] The manufacturing devices described in Patent Documents 1 and 2 are designed to laminate multiple plates of the same shape and bond them together by supplying high-frequency power between opposing electrodes, but are not designed to manufacture structures in which members of different shapes are laminated. Furthermore, the device described in Patent Document 3 is designed to heat-bond a face material and a frame portion in contact with it using an adhesive, but the manufacturing device uses a grid electrode and does not suggest the use of an opposing electrode plate.

[0005] Furthermore, when a workpiece to be processed that has multiple components is dielectrically heated and bonded between opposing electrodes, if the dimensional accuracy of each dielectric is low or if the shapes of each dielectric are different, the opposing electrodes cannot be set parallel, making it difficult to uniformly bond each dielectric.

[0006] The present invention has been made in view of the above, and provides a laminate manufacturing method and apparatus for simultaneously and uniformly bonding a main member and a plurality of sub-members having mutually different shapes by dielectric heating. [Means for solving the problem]

[0007] The laminate manufacturing method of the present invention includes a first step of arranging a main member, a first sub-member attached to the main member via an adhesive, and a second sub-member attached to the main member via an adhesive and having a shape different from that of the first sub-member, on opposing electrodes; and a second step of supplying high-frequency power between the opposing electrodes.

[0008] According to the present invention, a high-frequency electric field is uniformly distributed between the first and second sub-members at a level corresponding to their respective shapes, i.e., impedances. Therefore, the difference in the heating rates of the adhesives disposed between the first and second sub-members and the main member is reduced, resulting in uniform and strong curing (bonding). It is preferable that uniform heating is performed by heating each adhesive at least within the bonding temperature range, and further heating within a temperature range that does not cause any changes in the physical properties of the materials of the main member and the sub-members. The main member and the sub-members may be laminated with adhesive in advance and then placed on the opposing electrodes, or they may be placed in order on the opposing electrodes. Because the adhesive needs to be cured by dielectric heating, they may be placed before high-frequency power is supplied between the opposing electrodes.

[0009] Furthermore, one of the opposing electrodes is divided into first and second divided electrodes so as to face the first and second sub-components, and the first divided electrode and the second divided electrode are connected by a conductive material. According to this configuration, it is preferable that adjacent divided electrodes are connected by a conductive material. Each divided electrode generates a uniform electric field equivalent to that of a single electrode, uniformly heating the adhesive. Furthermore, even if the shapes of the sub-components vary, the divided electrodes each cover the same area, allowing for more uniform and parallel pressure application. Furthermore, this can accommodate cases where the pressure needs to be changed depending on the bonding area, and high-frequency power is supplied more uniformly.

[0010] The second step is characterized in that the first and second divided electrodes are individually pressed against the opposing first and second sub-members. With this configuration, even if the first and second sub-members have variations in shape, it is possible to apply pressure more uniformly by each divided electrode, and it is also possible to apply pressure at an appropriate pressure according to the bonding area.

[0011] Furthermore, the present invention provides an auxiliary member that aligns the heights of the first and second sub-members. With this configuration, by raising the lower sub-member to make the first and second sub-members the same height, the first and second sub-members are made electrically equivalent, and the electric field distribution is made uniform, making it possible to further reduce the difference in the temperature rise rate of the adhesive between the first and second sub-members.

[0012] Furthermore, the main member and the first and second sub-members are made of urethane resin foam reinforced with glass fiber. This configuration allows for the production of a laminated structure that is lightweight, high-strength, easy to process, and has a long life.

[0013] The adhesive is an epoxy resin, which has a high dielectric loss coefficient, and thus the adhesive can be heated more quickly before the temperature of the main member and the first and second sub-members rises to the foaming temperature.

[0014] The laminated body may also be a sleeper, in which case a highly durable sleeper that is lightweight, has high strength, is easy to process, and has a long life is produced.

[0015] In addition, the laminate manufacturing apparatus according to the present invention comprises an opposing electrode to which high-frequency power is supplied, a main member, and a clamping portion that clamps a first sub-member and a second sub-member having different shapes and that are attached to the main member via an adhesive between the opposing electrodes, one of the opposing electrodes being divided into first and second split electrodes so as to face the first and second sub-members, and the first split electrode and the second split electrode being connected by a conductive material.

[0016] According to the present invention, by providing split electrodes corresponding to the first and second sub-components, better contact between the split electrodes and the sub-components can be achieved compared to sandwiching the first and second sub-components between opposing single electrodes. Furthermore, by uniformly distributing high-frequency power to the opposing sub-components through each split electrode according to their size, the adhesive applied to the sub-components, for example, is uniformly and uniformly dielectrically heated by the crossing electric fields, reducing the difference in heating rate. In this way, the adhesive of each sub-component is simultaneously heated and hardened, efficiently bonding the opposing main and sub-components. Note that uniform heating is preferably achieved by heating the adhesive of each sub-component at least within the bonding temperature range, and further within a temperature range that does not cause any physical property changes in the materials of the main and sub-components.

[0017] The clamping portion presses the first divided electrode and the second divided electrode individually against the opposing first and second sub-members. This configuration makes it possible to apply pressure more uniformly by each divided electrode even if the sub-members have different shapes, and also makes it possible to apply pressure at an appropriate level according to the bonding area.

[0018] Preferably, the one electrode is a negative electrode (ground side). With this configuration, the heating efficiency is improved by the electric field distribution that accompanies the electrode side that is in contact with the main member being a positive electrode.

[0019] The device also includes a control means for supplying high frequency power at a first level during a first period, and then supplying high frequency power at a second level lower than the first level during a subsequent second period. This configuration makes it possible to efficiently cause the adhesive to undergo a curing reaction and ensure sufficient reaction time. [Effects of the Invention]

[0020] According to the present invention, it is possible to simultaneously and uniformly and firmly bond a main member and first and second sub-members having different shapes. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a configuration diagram showing an embodiment of a laminate manufacturing apparatus according to the present invention. [Figure 2] FIG. 2 is a schematic front view of the manufacturing apparatus shown in FIG. 1, seen from the front side with the housing almost omitted. [Figure 3] FIG. 2 is a schematic left side view of the manufacturing apparatus shown in FIG. 1, as viewed from the left side, with the housing almost omitted. [Figure 4] 10 is a schematic plan view for explaining a workpiece carrying-in / out driving unit, a workpiece width aligning driving unit, and the processing contents thereof. FIG. [Figure 5] FIG. 10 is a schematic plan view for explaining a work width alignment drive unit and its processing content. [Figure 6] 10 is a schematic plan view showing the positional relationship between the split electrodes raised and lowered by the workpiece pressure drive unit and each packing, as viewed from above. FIG. [Figure 7] 10 is a time chart illustrating an example of the relationship between the output of high-frequency power and the heating temperature of an adhesive applied to a workpiece. [Figure 8] 1 is a flowchart illustrating an example of a processing procedure for manufacturing a laminate. [Figure 9] 1 is a flowchart illustrating an example of a processing procedure for manufacturing a laminate. [Figure 10] These figures show an embodiment in which an auxiliary member is used to enable more uniform and stronger adhesion. (A) is a side view in which an auxiliary member for adjusting height is placed on the lower packing on either the left or right side, and (B) is a view taken from the arrow II in (A). [Figure 11] These are side views showing a structure in which an insulating cushioning material is sandwiched between the work packing and the split electrode. (A) shows a state in which the top surface of the packing is not exactly flat, and (B) shows a state in which the width dimensions of the base and the packing do not match and the top surface of the packing is inclined. DETAILED DESCRIPTION OF THE INVENTION

[0022] Fig. 1 is a configuration diagram showing one embodiment of a laminate manufacturing apparatus 1 according to the present invention. Fig. 2 is a schematic front view of the manufacturing apparatus 1 as seen from the front side with the housing 101 almost completely omitted. Fig. 3 is a schematic left side view of the manufacturing apparatus 1 as seen from the left side with the housing 101 almost completely omitted.

[0023] The manufacturing apparatus 1 has a housing 101 (see FIGS. 2 and 3) of a predetermined external shape, for example, a substantially rectangular parallelepiped shape, and includes a high-frequency oscillator 11 that generates high-frequency power inside, a heating unit 20 that heats and cures the adhesive Pa applied to the joining surface of the workpiece 40 by dielectric heating, and a control unit 30 consisting of a computer with a built-in processor that controls a series of manufacturing process steps. Connected to the control unit 30 are a memory unit 301 that stores control programs related to the manufacturing process steps and various information required for the processes, an operation unit 51 for inputting necessary instructions and information, and a display unit 52 that displays the process steps and input contents as images.

[0024] The control unit 30 executes a control program stored in the storage unit 301 on the main memory, thereby functioning as a thermal adhesion processing unit 31 and a pre- and post-processing unit 32. The thermal adhesion processing unit 31 controls the process of outputting high-frequency power to the heating unit 20 under predetermined conditions to dielectrically heat the adhesive Pa. The pre- and post-processing unit 32 performs predetermined processing on the workpiece 40 before and after the thermal adhesion process on the workpiece 40. More specifically, the pre- and post-processing unit 32 includes a workpiece loading / unloading processing unit 321, a workpiece width alignment processing unit 322, and a workpiece pressure processing unit 323. The control unit 30 is also connected to a workpiece loading / unloading driving unit 61, a workpiece width alignment driving unit 62, and a workpiece pressure driving unit 63. The configurations and operations of these units will be described later.

[0025] The high-frequency oscillator 11 is capable of outputting power of, for example, several kilowatts to several hundred kilowatts in response to an instruction, and outputs power in the 1 MHz to 100 MHz band, preferably in the tens of MHz band. The output high-frequency power is supplied to the heating unit 20 via a power feed line 12. Although not shown in the figure, a known matching box is provided midway along the power feed line 12.

[0026] The heating unit 20 has a structure in which opposing plate-shaped electrodes 21 and 22 are arranged. When high-frequency power is supplied between the parallel electrodes 21 and 22, the heating unit 20 heats and hardens the adhesive Pa in the object to be processed (hereinafter, workpiece 40) held between the electrodes 21 and 22.

[0027] Various structural materials and the like can be used as the workpiece 40, and in this embodiment, a sleeper, for example, a bridge sleeper, is assumed. The workpiece 40 for a bridge sleeper includes a rectangular pillar-shaped base body 41 having at least a length dimension sufficient to straddle a railway rail, and a predetermined number of, for example, two, packings 421, 422 having a predetermined shape that are spaced apart in the longitudinal direction of the base body 41. In this embodiment, the base body 41 corresponds to the main member according to the present invention, and the packings 421, 422 correspond to the secondary member according to the present invention.

[0028] The base 41 and packings 421, 422 are made of a dielectric material and are rapidly heated by high-frequency dielectric heating, which promotes hardening of the adhesive. The packings 421, 422 refer to materials interposed between the base 41 and the electrode 22. The packings 421, 422 are preferably made of the same material as the base 41. Alternatively, the packings 421, 422 may be made of the same material, but with different densities, for example. Furthermore, an adhesive Pa is applied to the contact surfaces between the base 41 and the packings 421, 422 of the workpiece 40. Thermosetting resins such as epoxy resins, phenolic resins, and resorcinol resins that crosslink through chemical reactions can be used as the adhesive, with epoxy resin being particularly preferred. The base 41, packings 421, 422, and adhesive Pa may be any material that can adhere to each other. The pressure applied between the main component (base 41) and the secondary component (gasket 421 (422)) may be such that it does not exceed their elastic deformation range, preferably exceeding 0.1 MPa and less than 1 MPa, and even more preferably less than 0.5 MPa.

[0029] 1 shows an example of the shape of workpiece 40. Base 41 of workpiece 40 abuts against electrode 21, and packings 421 and 422 abut against split electrodes 221 and 222 (described later) so as to face each other. As shown in FIG. 2, when packings 421 and 422 are different in height, lower packing 422 may be abutted against split electrode 222 via height-adjusting auxiliary member 420.

[0030] The gaskets 421, 422 may be identical or different in shape depending on the specifications, as shown in Figure 1, and are manufactured to at least fit the spacing between the bridge girders to be laid. The bridge sleepers (workpieces 40) are used upside down, with the gaskets 421, 422 facing downwards and laid side by side on the top surface of the bridge girders, and two rails are laid in appropriate locations on the top surface of the upper base 41, allowing a railway to be laid on the bridge. In addition to wood, it is desirable to use a hard resin molded body for the workpieces 40, given the requirements for light weight, high strength, ease of processing, and long life, and a urethane resin material is preferred, for example. Examples of urethane resin materials include glass fiber-reinforced urethane resin foam (Eslon Neo Lumber: FFU, manufactured by Sekisui Chemical).

[0031] The electrode 21 has an electrode surface that is larger than the length L and width W of the base 41 of the workpiece 40. By making the electrode surface wider compared to the size of the workpiece 40, the entire workpiece 40 is heated more uniformly and the high electric field generated at the edges of the electrode surface is prevented from being applied to the workpiece 40 and causing partial overheating. In this embodiment, the electrode 21 is arranged on the lower side, and the split electrodes 221 and 222 are arranged on the upper side. Note that, of the electrode 21 and the split electrodes 221 and 222, a configuration in which the electrode 21 is the positive electrode or the negative electrode (earth side) can be adopted. In this embodiment, however, the power supply line 12 is wired so that the electrode 21 side is the positive electrode and the split electrodes 221 and 222 are the negative electrodes, which is a configuration in which dielectric heating is more efficient. In addition to a configuration in which the positive electrode side is on the upper side, the heating unit 20 may be arranged so that the negative electrode side is on the upper side.

[0032] 1 and 2, split electrodes 221, 222 are arranged at a predetermined distance in the longitudinal direction (left-right direction in FIG. 2) of electrode 21. The widthwise dimension (depthwise direction in FIG. 2) of split electrodes 221, 222 is approximately the same as that of electrode 21 (see FIG. 3), and the longitudinal dimension is a size that covers at least the entire upper surface of the corresponding packings 421, 422. Split electrodes 221, 222 may be the same size or different sizes.

[0033] The metal plate 220 is strip-shaped and made of a conductive material such as a copper plate, and both ends are connected to the split electrodes 221 and 222. The metal plate 220 can be formed in various shapes. In this embodiment, the metal plate 220 is configured to be elastically deformable, bending upward. By appropriately designing the length, width, etc. of the metal plate 220, it also functions as the inductance L component of the matching circuit. By configuring the metal plate 220 to be elastically deformable, any error in the height dimensions of the packings 421 and 422 can be absorbed by the elastic deformation. The metal plate 220 may have an elastically deformable structure or a mechanically deformable shape. The provision of the metal plate 220 makes the split electrodes 221 and 222 equivalent to a single electrode, allowing a high-frequency current corresponding to the impedance difference between the packings 421 and 422 to flow in a distributed manner.

[0034] Next, the control unit 30 will be described. The thermal bonding processing unit 31 is executed with the workpiece 40 set in the heating unit 20, and details will be described later. In the pre- and post-processing unit 32, the workpiece loading / unloading processing unit 321 loads the workpiece 40 into the heating unit 20 and generates processing signals to unload the heated workpiece 40 from the heating unit 20, and outputs the processing signals to the workpiece loading / unloading driving unit 61. The workpiece width alignment processing unit 322 generates processing signals to align the workpiece 40 loaded into the heating unit 20 to a predetermined position in the width direction of the electrode 21, and outputs the processing signals to the workpiece width alignment driving unit 62. The workpiece pressure processing unit 323 lowers the split electrodes 221, 222 relative to the workpiece 40 whose width has been aligned in the heating unit 20. In an embodiment equipped with a pressure sensor, the workpiece pressure processing unit 323 generates processing signals to apply pressure at a predetermined pressure, and also generates processing signals to raise the split electrodes 221, 222 to an open position after heating, and outputs the processing signals to the workpiece pressure driving unit 63. Note that the amount of lift may be controlled by a movement amount sensor instead of a pressure sensor. Next, the configuration and processing of each unit will be described in more detail with reference to FIGS.

[0035] Within the housing 101, the heating section 20 is located approximately in the center, and surrounding the heating section 20, there are workpiece loading / unloading drive sections 61 (see Figure 2) on both the left and right sides, workpiece width alignment drive sections 62 (see Figure 3) on both the front and back sides, and a workpiece pressure drive section 63 (see Figures 2 and 3) on the upper side.

[0036] An insulating structure for setting the electrode 21 as a positive electrode is provided below the heating unit 20. In this embodiment, support plates 102 are erected on both sides of the electrode 21 in the longitudinal direction (the left-right direction in FIG. 2), and the electrode 21 is supported upward by the support plates 102, with a power feed line 12 wired from approximately the center below. Although not visible in FIG. 2, the power feed line 12 is wired to the split electrodes 221 and 222 as shown in FIG. 1.

[0037] Fig. 4 is a schematic plan view illustrating the workpiece loading / unloading drive unit 61, the workpiece width alignment drive unit 62, and the processing contents thereof. Fig. 5 is a schematic plan view illustrating the workpiece width alignment drive unit 62 and the processing contents thereof. Fig. 6 is a schematic plan view, viewed from above, showing the positional relationship between the split electrodes 221, 222 and the packings 421, 422, which are raised and lowered by the workpiece pressure drive unit 63.

[0038] The workpiece loading / unloading drive unit 61 includes a nip roller unit 611 and a pusher 612 (see FIGS. 2 and 4), and multiple rollers (see FIG. 2) are arranged on the upstream and downstream sides to form a conveying path. The nip roller units 611 are arranged in pairs in the width direction on the loading / unloading side for loading and unloading, and are configured to be switchable between a retracted position and a nip position. As shown in FIG. 4, the nip roller unit 611 is rotated around a vertical axis by a drive source such as a motor at the nip position to load the nipped workpiece 40 into the heating unit 20, and on the unloading side, the heat-treated workpiece 40 is unloaded. The pusher 612 is a rod-shaped body provided only on the loading side and reciprocatable in the loading / unloading direction by an actuator (not shown) or the like. The pusher 612 pushes the workpiece 40 that has been brought into the heating section 20 to a predetermined heating position on the electrode 21 as shown in Figures 2 and 5, and also transports the heat-treated workpiece 40 to the position of the nip roller section 611 on the discharge side.

[0039] The workpiece width alignment drive units 62 are arranged on both sides of the width direction, sandwiching the packings 421, 422. In this embodiment, a predetermined number of workpiece width alignment drive units 62, for example, two, are arranged on one side of the width direction, and the same number of two workpiece width alignment drive units 62' are arranged on the other side. As shown in Figures 3 and 4, all of these units have the same configuration. To explain the workpiece width alignment drive unit 62 as a representative example, the workpiece width alignment drive unit 62 includes a threaded shaft 621 extending in the width direction at the top of the housing 101 and a nut unit 622 meshing with the threaded shaft 621. The nut unit 622 reciprocates in the width direction when the threaded shaft 621 is rotated by a motor (not shown) or the like. The nut unit 622 extends downward, and further includes a nut unit 623 at its bottom that moves up and down when the threaded shaft 6221 is rotated by a motor or the like. The nut portion 623 extends horizontally, and at the tip thereof, a predetermined number of protruding portions (here, two protruding portions 6231, 6232) are arranged vertically and protruding by the same dimension.

[0040] The workpiece width alignment drive units 62 are capable of reciprocating motion between a retracted position in the width direction (solid line position in FIG. 4 ) and an abutment position (dashed line position in FIG. 4 ) that is a position beyond the end of the electrode 21. When the workpiece 40 is carried in, as shown by the solid lines in FIG. 5 , the two workpiece width alignment drive units 62 on one side (the right side in FIG. 5 ) first move from the retracted position to the abutment position, and the protrusions 6231, 6232 abut against the base 41 and packings 421, 422 of the workpiece 40 to align them so that they are flush with each other. While maintaining this state, the workpiece width alignment drive unit 62′ on the opposite side is then moved from the retracted position toward the abutment position and similarly abuts against the opposite surface of the workpiece 40. In this way, a reference abutment position is first set on one side, and then the workpiece 40 is positioned from both sides in the width direction by pressing it from the opposite side in this state. As shown in FIG. 6, the packings 421 and 422 are abutted so as to overlap at approximately the center of the corresponding split electrodes 221 and 222, thereby preventing the influence of the high electric field at the electrode edges and enabling more uniform heating.

[0041] As shown in FIG. 2, the workpiece pressure drive unit 63 includes multiple, e.g., two, workpiece pressure mechanisms 631a, 631b, 632a, and 632b, each of which has the same longitudinal configuration and corresponds to the split electrodes 221 and 222, and each of which is attached to the ceiling of the housing 101. Taking the workpiece pressure mechanisms 631a and 631b as representative examples, the workpiece pressure mechanisms 631a and 631b are actuators equipped with, for example, rods that can move up and down at their lower portions, and support a horizontal support plate 6311 at their lower ends. The split electrodes 221 are attached to the lower portion of the horizontal support plate 6311 via a plurality of insulating plates 6312. The workpiece pressure mechanisms 631a and 631b may be driven to move up and down while referring to a displacement sensor or the like. Alternatively, the workpiece pressure mechanism 631a (or 631b) closest to the packing 421 may be selectively driven to move up and down. In this case, split electrode 221 can be kept as horizontal as possible and the entire upper surface of packing 421 can be pressed more uniformly.

[0042] 7 is a time chart illustrating an example of the relationship between the output of high-frequency power and the heating temperature of the adhesive Pa applied to the workpiece 40. Here, the heating of the adhesive Pa will be explained. The high-frequency power supplied from the power supply line 12 generates a high-frequency electric field between the electrode 21 and the split electrode 221 and between the electrode 21 and the split electrode 222, and the electric field is concentrated within the base 41 and the packings 421, 422, which are dielectrics sandwiched between them. The concentrated electric field is also distributed inside the layer of the adhesive Pa between the base 41 and the packings 421, 422, and is effectively used for dielectric heating.

[0043] When the adhesive Pa hardens, it is necessary to maintain the reaction temperature range for the curing reaction and ensure the reaction time. The heat bonding processing unit 31 controls the output of the high-frequency power in three stages: high-frequency heating I, standby, and high-frequency heating II in this embodiment. The three-stage control is set by the output level and the output period. As the setting conditions, various physical properties of each member of the workpiece 40 are used, such as size (shape, volume), dielectric constant, dielectric loss angle, conductivity, and initial temperature. Furthermore, a calculation formula derived from simulations and actual tests is applied. As is well known, for calculating the calorific value, the volume of the adhesive, the dielectric loss coefficient of the adhesive, the curing reaction temperature and reaction time of the adhesive, the operating frequency, the output voltage, and the electrode distance information are applied.

[0044] As shown in FIG. 7, in the first-stage high-frequency heating I, the output is performed at a predetermined level P1 for a time t1, guiding the temperature T of the adhesive Pa between the reaction temperature ranges T2 to T1. Here, in order to suppress overshoot, as the second stage, the output is set to a low level, typically stopped, for a predetermined time toff until the temperature rise stabilizes. After that, in order to ensure the curing reaction time, the supply of high-frequency power is performed at a predetermined level P2 (<P1) for a predetermined time t2 by the third-stage high-frequency heating II. Note that the output pattern of the high-frequency power is not limited to the three-stage method shown in FIG. 7, and any pattern may be used as long as it can stably adjust the temperature of the adhesive Pa within the curing reaction temperature range and ensure the curing reaction time. By setting an output pattern in which the temperature does not exceed these ranges, it is possible to prevent the workpiece 40 that is heated simultaneously from being overheated and deformed or deteriorated. Further, the output pattern of the high-frequency power may be set corresponding to the curing reaction temperature and reaction time according to the type of the adhesive. Furthermore, an output control mode may be adopted, such as measuring the temperature near the adhesive Pa with a radiation thermometer.

[0045] FIG. 8 and FIG. 9 are flowcharts showing an example of a processing procedure for manufacturing a sleeper from a workpiece 40. First, when a sensor detects that the tip of the workpiece 40 sent from the conveyance path has been conveyed to the carry-in port beyond the nip roller unit 611 (step S1), for example, information regarding the workpiece 40 that has been previously associated with the carry-in order is acquired (step S3), and based on the acquired information, information such as the movement amount of each part in the pre-treatment is set, and calculation and setting are performed according to the calculation formula of the heat bonding treatment conditions (step S5). Next, the nip roller unit 611 is driven to carry in the workpiece 40 to the rear end, and subsequently, the pusher 612 is driven on the conveyance path to push in the rear end of the workpiece 40, thereby carrying it to the central position on the electrode 21 (step S7).

[0046] Subsequently, alignment processing in the width direction of the workpiece 40 is performed by the workpiece width alignment drive unit 62 (step S9). When the alignment processing ends, the selected workpiece pressing mechanism units (for example, the workpiece pressing mechanism units 631a and 632a in FIG. 2) are driven from the workpiece pressing drive unit 63, and the divided electrodes 221 and 222 are lowered by a predetermined dimension to press the workpiece 40 at a predetermined pressure set according to, for example, the bonding area (step S11).

[0047] When the pre-treatment ends as described above, next, a heat bonding treatment is performed by the heat bonding treatment unit 31. First, high-frequency heating I is performed at a predetermined level P1 for t1 hours to lead the temperature T of the adhesive Pa into the reaction temperature range T2 to T1 (step S13). Here, in order to suppress overshoot, the output is set to a low level, typically the output is stopped, for a predetermined time toff until the temperature rise stabilizes (step S15). After this, in order to ensure the reaction time, high-frequency heating II is performed to supply high-frequency power at a predetermined level P2 (<P1) for a predetermined time t2 (step S17).

[0048] When the heat bonding process is completed in this manner, post-processing begins. First, the split electrodes 221, 222 are raised and the pressure is released (step S19). Next, it is determined whether the manufacturing process for all workpieces has been completed (step S21). If not, the process proceeds to step S23. In step S23, it is determined whether the next workpiece 40 has been detected at the carry-in entrance (step S23). If detected, information about the detected workpiece 40 is acquired (step S25). Based on the acquired information, information such as the amount of movement of each part in the pre-processing is set, and the heat bonding process conditions are calculated and set using a formula (step S27).

[0049] Next, as pre- and post-processing, the heat-treated workpiece 40 is carried out and the next workpiece 40 is carried in conjunction with each other (step S29). More specifically, the next workpiece 40 is carried in by the nip roller unit 611, and then carried in further by the pusher 612. At the same time, the leading edge of the workpiece pushes the rear end of the heat-treated workpiece 40, pushing the heat-treated workpiece 40 to the position of the nip roller unit 611 at the carry-out port. The heat-treated workpiece 40 is then carried out by the nip roller unit 611 at the carry-out port. Next, the process returns to step S9 and repeats the same process. On the other hand, if it is determined in step S21 that the manufacturing process has ended, the process proceeds to step S31. In step S31, the leading edge of the heat-treated workpiece 40 is first pushed out by the pusher 612 to the position of the nip roller unit 611 on the carry-out port side, and then the workpiece is carried out of the heating unit 20 by the nip roller unit 611.

[0050] Here, various forms of packing to which the present invention can be applied will be described. When the upper and lower opposing electrodes are both single-piece, the electrode surfaces have a uniform potential. Even if the left and right packings are arranged separately, if they are made of the same material, high-frequency power is distributed and supplied according to the impedance of each packing, and the applied adhesive Pa is uniformly heated and cured to bond the packings. However, if the left and right packings are not identical in shape, or if the packings are identical in shape but have variations in shape due to manufacturing precision, if both electrodes are single-piece, it becomes difficult to uniformly contact the multiple packings with the electrodes or to apply pressure according to the contact area, and uniform heating may not be possible.

[0051] In such a case, by using split electrodes 221, 222 for one of them, for example, the above-mentioned problems that occur with a single electrode can be eliminated, and by using metal plate 220 to make each of split electrodes 221, 222 the same potential, power from high-frequency oscillator 11 can be distributed and supplied according to the load impedance of each split electrode, and as a result, the heating temperature of adhesive Pa can be raised within a specified range, enabling uniform heating and uniform adhesion.

[0052] Furthermore, for example, by applying pressure to the corresponding split electrodes individually in proportion to the cross-sectional size of the left and right packings, the left and right packings can be pressurized with a uniform pressure. Furthermore, the number of packings is not limited to two (left and right) but may be three or more, and split electrodes may be prepared corresponding to each of them.

[0053] Next, Figure 10 shows an embodiment that enables more uniform and strong adhesion using an auxiliary member 420. (A) is a side view of the auxiliary member 420 for height adjustment placed on the lower packing 422, and (B) is a view taken along arrow II in (A). The auxiliary member 420 and packings 421 and 422 are preferably made of the same material. The auxiliary member 420 has the same cross-sectional shape as the packing 422 and has a height dimension that matches the height of the packing 421 when placed on top of the packing 422. By making the height of the packing 421 equal to the combined height of the packing 422 and the auxiliary member 420, the electric field density generated inside the packings 421 and 422 is uniform. In this case, the cross-sectional shapes or sizes of the packings 421 and 422 do not need to be identical.

[0054] On the other hand, an auxiliary member can be provided even when the left and right packings are made of different materials, and by matching the electric field density generated in the adhesive Pa applied to the left and right packings, the adhesive Pa of both the left and right packings will be heated and cured simultaneously. It is preferable that the auxiliary member be made of the same material and have the same cross-sectional shape as the packing whose adhesive Pa is heated and cured faster (hereinafter referred to as "one of the packings"). By placing the auxiliary member between the secondary member (packing) and the electrode, the electric field density generated in the adhesive Pa of both the left and right packings can be matched.

[0055] FIG. 11 is a side view showing a structure in which an insulating cushion material 81 is sandwiched between a packing 421 of the workpiece 40 and an electrode 221. (A) shows a state in which the top surface of the packing 421 is not exactly flat, and (B) shows a state in which the width dimensions of the base 41 and the packing 421 are not identical and the top surface of the packing 421 is inclined. By using an insulating cushion material 81, problems such as heat generation due to the skin effect in metals and discharge due to localized high-frequency concentration do not occur. In the case of (A), the cushion material 81 is firmly pressed against a portion of the packing 421 (e.g., the center), and lateral sliding is restricted by high friction, making poor contact and misalignment unlikely. In the case of (B), the cushion material 81 is pressed against the edge of the acute angle side (left side of the figure) of the top surface of the packing 421, and lateral sliding is restricted by high friction, making poor contact and misalignment unlikely.

[0056] Next, an experiment on the presence or absence of adhesion between the main member and the sub-member will be described based on Table 1.

[0057] [Table 1]

[0058] In Table 1, the conditions are that the main member corresponding to the base 41 and the sub-members corresponding to the left and right gaskets 421, 422 are all made of FFU, and the adhesive Pa applied to each joint surface between the main member and the left and right sub-members is epoxy resin. The auxiliary members are made of the same material as the sub-members. The heating section is arranged in the following order from bottom to top: lower electrode, main member, sub-member, and upper electrode. The experiment was conducted using electromagnetic field simulation software Femtet (registered trademark) (manufactured by Murata Software Co., Ltd.).

[0059] In Example 1, Comparative Example 1, and Example 2, the left and right sub-members had different lengths L but the same height H, and no auxiliary members were used. Furthermore, in Example 1, the upper electrode was a single piece, whereas in Comparative Example 1 and Example 2, the upper electrode was a two-piece split electrode. Under these conditions, a predetermined high-frequency power was supplied between the upper and lower electrodes for a predetermined time, and an experiment was conducted.

[0060] In Example 1, the main member and the secondary member were bonded. The heating temperature of the adhesive Pa applied to the left and right secondary members was approximately uniform. When the heights of the left and right secondary members were the same, it was considered that the electric field distribution was uniform within each secondary member and between the left and right secondary members even if a single sheet was used for the upper electrode, and the applied adhesive Pa was heated approximately uniformly and cured by heating, which confirmed that the members were firmly bonded.

[0061] In Comparative Example 1, the upper electrode was divided into two split electrodes, one on the left and one on the right, corresponding to the left and right sub-members. The two split electrodes, one on the left and one on the right, correspond to split electrodes 221 and 222. Other conditions were the same as in Example 1.

[0062] In Comparative Example 1, the main component and the secondary component were not bonded. There was a large difference in the heating temperature of the adhesive Pa applied to the left and right secondary components, and the adhesive Pa applied to the secondary component with the longer length L in particular was hardly heated at all. This is thought to be because the distribution of power to the secondary component with the longer length L was relatively suppressed.

[0063] Example 2 employed the same configuration as Comparative Example 1, and furthermore, the left and right split electrodes were connected with a conductive material. Other conditions were the same as those of Example 1.

[0064] In Example 2, the main member and the sub-member were bonded. The heating temperature of the adhesive Pa applied to the left and right sub-members was approximately uniform. By interposing a conductive material between the left and right split electrodes in this way, the adhesive Pa could be heated uniformly regardless of the shapes and asymmetrical arrangement of the left and right sub-members.

[0065] Example 3 is a case where the heights H of the left and right sub-members are different, and an auxiliary member is placed on the upper surface of the sub-member with the lower height H, and the other configurations are the same as Example 2. The auxiliary member has a height dimension such that when placed on top of the sub-member with the lower height H, in other words, in a raised state, the upper surface of the auxiliary member coincides with the upper surface of the sub-member with the higher height H.

[0066] In Example 3, the main member and the secondary member were bonded. The heating temperature of the adhesive Pa applied to the left and right secondary members was approximately uniform. By placing an auxiliary member made of the same material on the secondary member with the lower height H and matching its height with the other secondary member, heating under conditions similar to those in Example 2 was possible, and uniform heating was achieved regardless of the shape or asymmetrical arrangement of the left and right secondary members. More specifically, the secondary member with the lower height H had a correspondingly smaller impedance, so power distribution did not correspond to the cross-sectional size of the other secondary member, and the electric field densities did not match. In this case, if the auxiliary member was placed on the secondary member with the lower height H and the heights were matched, power was distributed according to the cross-sectional sizes of both secondary members, and the electric field densities generated on both secondary members became equal (uniform). As a result, the adhesive Pa applied to both secondary members was heated uniformly. Furthermore, using the auxiliary member made it possible to more uniformly heat the heating temperature of the adhesive Pa applied to the left and right secondary members, enabling stronger bonding.

[0067] On the other hand, in Comparative Example 2, the shape and arrangement of the left and right sub-members were the same as in Example 3, but the difference was that no auxiliary member was provided. It was found that in Comparative Example 2, the main member and sub-members were not bonded. This is thought to be because the sub-member with the lower height H had a lower impedance compared to the other sub-member due to its lower height, and therefore received a relatively larger allocation of high-frequency power, resulting in it being heated to a higher temperature.

[0068] Next, Examples 4 and 5 show the relationship between the polarity of the lower electrode and the upper electrode and the heating efficiency. Examples 4 and 5 are identical except for the polarity of the electrodes. Furthermore, since the height H of the left and right sub-members is the same, no auxiliary member was used. In Example 4, the upper electrode was a positive electrode and the lower electrode was a negative electrode (ground). In Example 5, the upper electrode was a negative electrode (ground) and the lower electrode was a positive electrode.

[0069] In both Examples 4 and 5, the main member and the sub-member were bonded together. While the heating temperature was similarly uniform in both Examples 4 and 5, Example 5 showed a higher temperature rise. Therefore, it was found that heating efficiency was higher when the upper electrode was negative (earthed), as in Example 5. This is thought to be mainly due to the relationship between the long main member and the polarity, which caused the distribution of the high-frequency electric field to be more concentrated on the sub-member, resulting in a difference in heating efficiency.

[0070] In the above embodiment, a sleeper is used as an example of a laminate, but the present invention is not limited to sleepers and can also be applied to various industrial structural materials, architectural structural materials, and decorative materials (building materials) as laminates formed by assembling wood and resin. [Explanation of symbols]

[0071] 1 Manufacturing equipment 11 High-frequency oscillator 20 Heating section 21 electrodes 220 Metal plate (conductive material) 221,222 split electrode 30 Control Unit 31 Heating and Adhesion Processing Section 32 Pre- and post-processing section 40 Work 41 Base (main member) 421, 422 Packing (secondary material) Pa Adhesive

Claims

1. a first step of arranging a main member, a first sub-member provided on the main member via an adhesive, and a second sub-member provided on the main member via an adhesive and having a shape different from that of the first sub-member, on a counter electrode; a second step of supplying high frequency power between the opposing electrodes.

2. 2. The laminate manufacturing method according to claim 1, wherein one of the opposing electrodes is divided into first and second divided electrodes so as to face the first and second sub-members, and the first divided electrode and the second divided electrode are connected by a conductive material.

3. 3. The laminate manufacturing method according to claim 2, wherein the second step presses the first and second divided electrodes individually against the opposing first and second sub-members.

4. The laminate manufacturing method according to claim 1 , further comprising the step of disposing an auxiliary member for adjusting the height of the first sub-member and the second sub-member.

5. 2. The method for manufacturing a laminate according to claim 1, wherein the main member and the first and second sub-members are made of urethane resin foam reinforced with glass fibers.

6. 2. The method for manufacturing a laminate according to claim 1, wherein the adhesive is an epoxy resin.

7. The method for manufacturing a laminate according to any one of claims 1 to 6, wherein the laminate is a railroad tie.

8. a counter electrode to which high frequency power is supplied; a main member; and a clamping portion that clamps a first sub-member and a second sub-member, which are provided on the main member via an adhesive and have different shapes, between the opposing electrodes; A laminate manufacturing apparatus in which one of the opposing electrodes is divided into first and second divided electrodes so as to face the first and second sub-members, and the first divided electrode and the second divided electrode are connected by a conductive material.

9. The laminate manufacturing apparatus according to claim 8 , wherein the clamping unit individually presses the first divided electrode and the second divided electrode against the first and second sub-members that face each other.

10. The laminate manufacturing apparatus according to claim 8 , wherein the one electrode is a negative electrode.

11. 11. The laminate manufacturing apparatus according to claim 8, further comprising a control means for supplying high frequency power at a first level during a first period, and supplying high frequency power at a second level lower than the first level during a subsequent second period.

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