Conveying / heating device

Abstract

To prevent a work-piece from staying in a connection section between conveyance conveyors.SOLUTION: In a conveying / heating device, in which a heating zone, a decompression zone and a cooling zone are sequentially arranged, conveyance conveyors are provided on the heating zone, the decompression zone and the cooling zone respectively, and a pusher for pushing out a work-piece is provided on an inlet side of the decompression zone.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a transporting and heating device that is applied to a reflow apparatus that transports a workpiece as an object to be heated using a transport conveyor. [Background technology]

[0002] In order to prevent bubbles from remaining in the molten solder joint, a reflow apparatus has been proposed in which a reduced pressure chamber (hereinafter referred to as a reduced pressure zone) that reduces the atmospheric pressure is provided in the transport path of the workpiece (hereinafter referred to as a substrate), and degassing is performed in the reduced pressure zone (see, for example, Patent Document 1). In the reduced pressure zone, a vacuum is drawn by a vacuum pump to degas the solder joint, and once the degassing process is complete, the reduced pressure zone is opened to the atmosphere and nitrogen gas, for example, is introduced.

[0003] In a typical reflow soldering machine, a single conveyor is used from the heating zone to the cooling zone. In a vacuum reflow soldering machine, a single continuous conveyor cannot be installed in the heating zone, the decompression zone, and the cooling zone because the decompression zone must be evacuated. Therefore, in order to continuously transport boards, multiple separate conveyors are installed, such as a conveyor inside the decompression zone, a conveyor on the entrance side of the decompression zone, and a conveyor on the exit side of the decompression zone. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6076263 Summary of the Invention [Problem to be solved by the invention]

[0005] When the conveyors before and after the decompression zone and the conveyor within the decompression zone are installed separately, there are transfer sections where the conveyor is interrupted at both the entrance and exit sides of the decompression zone. This creates a problem where the transfer of substrates is not smooth and substrates become stuck.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an improved conveying and heating device that does not cause such problems. [Means for solving the problem]

[0007] The present invention provides a conveying and heating device in which a heating zone, a decompression zone, and a cooling zone are sequentially arranged, A conveyor is provided in each of the heating zone, the decompression zone, and the cooling zone, This is a conveying and heating device equipped with a pusher that pushes out the workpiece at the entrance side of the decompression zone. [Effects of the Invention]

[0008] According to at least one embodiment, the pusher can prevent workpieces from being stuck in the transfer section of the transport conveyor. Note that the effects described here are not necessarily limited, and any of the effects described in this disclosure may be used. Furthermore, the contents of the present invention should not be interpreted as being limited by the effects exemplified in the following description. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an outline of a reflow apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a graph showing an example of a temperature profile during reflow. [Figure 3] FIG. 3 is a cross-sectional view of a reduced pressure zone in one embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of a reduced pressure zone enclosure in one embodiment of the present invention. [Figure 5]FIG. 5 is a perspective view of a pusher according to one embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged perspective view of a portion of a pusher in accordance with one embodiment of the present invention. [Figure 7] FIG. 7 is a schematic diagram for explaining a position switching mechanism according to one embodiment of the present invention. [Figure 8] FIG. 8A is a schematic diagram showing a cross section of a throat portion in one embodiment of the present invention, and FIG. 8B is a schematic diagram showing a cross section of a reflow furnace in one embodiment of the present invention. [Figure 9] FIG. 9 is a block diagram of an example of a control device that controls the operation of the pusher. [Figure 10] FIG. 10 is a schematic plan view for explaining the operation of the pusher. [Figure 11] FIG. 11 is a graph for explaining the operation of the pusher. BEST MODE FOR CARRYING OUT THE INVENTION

[0010] An embodiment of the present invention will be described below. Note that the embodiment described below is a preferred specific example of the present invention, and various technically preferable limitations are attached, but the scope of the present invention is not limited to these embodiments unless otherwise specified in the following description to the effect that the present invention is limited.

[0011] FIG. 1 shows a schematic configuration of a reflow apparatus 101 according to one embodiment of the present invention. The reflow apparatus 101 includes a reflow furnace 102, transport conveyors such as transport chains 103, 104, and 105 that pass a workpiece, such as a rectangular printed wiring board, a printed circuit board (hereinafter simply referred to as a board) W having surface-mount electronic components and solder mounted on both sides thereof through the reflow furnace 102, and an outer plate 106. The outer plate 106 is a case that covers the entire structure. Each transport chain is made up of two parallel transport chains on which the board W is placed. Furthermore, a chain that transports anti-warp pins that support the underside of the board W may be provided between the two parallel transport chains.

[0012] After being carried into reflow furnace 102 through carry-in entrance 107, substrate W is transported by transport chains 103, 104, and 105 in the direction of the arrow (from left to right in FIG. 1) at a predetermined speed, and is finally removed from carry-out exit 108. Although not shown, a substrate carry-in device for carrying in substrate W is provided before carry-in entrance 107, and a substrate carry-out device for sending substrate W to the outside is arranged after carry-out exit 108. In the following description, the transport direction of substrate W is defined as the x direction, the width direction perpendicular to the transport direction is defined as y, and the height direction is defined as z.

[0013] A throat section 109 is provided between the reflow furnace 102 and the inlet 107, and a throat section 110 is provided between the reflow furnace 102 and the outlet 108. The throat sections 109 and 110 function as seals that isolate the inside of the reflow furnace 102 from the outside and prevent an increase in the oxygen concentration inside the furnace. The throat sections 109 and 110 are configured as, for example, labyrinth seals.

[0014] The reflow furnace 102 is divided into, for example, nine zones Z1 to Z9 along the transport path from the inlet 107 to the outlet 108, and these zones Z1 to Z9 are arranged in-line. Seven zones Z1 to Z7 from the inlet 107 side are heating zones, and two zones Z8 and Z9 on the outlet 108 side are cooling zones. Forced cooling units (not shown) are provided in association with the cooling zones.

[0015] Each of zones Z1 to Z6 is composed of an upper furnace body having an upper heating unit including a blower and a lower furnace body having a lower heating unit including a blower. Zone Z7, located after zone Z6, is a zone (hereinafter referred to as decompression zone Z7) for heating and degassing the molten solder joints. Decompression zone Z7 has, for example, a heater for heating at its top. Note that the number of zones is merely an example, and other numbers of zones may be provided.

[0016] The transport chain 103 is provided to transport the substrate W from the inlet 107 to the entrance of the reduced pressure zone Z7. The transport chain 104 is provided to take the substrate W into the reduced pressure zone Z7 and send the substrate W, which has been subjected to degassing treatment in the reduced pressure zone Z7, out of the reduced pressure zone Z7 to the transport chain 105. The transport chain 105 is provided to transport the substrate W sent out of the reduced pressure zone Z7 towards the outlet 108. Note that other configurations are also possible for the transport mechanism for the substrate W.

[0017] The depressurization zone Z7 includes, for example, an entrance shutter and an exit shutter (hereinafter, these shutters will be referred to as gate valves). When the gate valve is closed, the depressurization zone Z7 has an airtight structure. When the gate valve is opened, the depressurization zone Z7 is opened, and the substrate W after degassing is sent to zone Z8 (cooling zone), and the next substrate W to be processed is taken into the depressurization zone Z7 from zone Z6.

[0018] The gate valve is closed, the decompression zone Z7 is sealed, and a vacuum is drawn by a vacuum pump. By reducing the pressure in the decompression zone Z7, a degassing process is performed on the molten solder joints of the substrate W. After the degassing process is completed, the decompression zone Z7 is opened to the atmosphere, and nitrogen gas or the like is introduced, and the gate valve is opened. Note that a configuration other than a gate valve can also be used to switch the decompression zone Z7 between sealed and open states.

[0019] The above-mentioned multiple zones Z1 to Z9 control the temperature of the heated object according to a temperature profile during reflow. Figure 2 shows an example of a temperature profile for continuous transport. The horizontal axis represents time, and the vertical axis represents the surface temperature of the heated object, such as a printed wiring board with electronic components mounted on it. The first section is the temperature rise section R1, where the temperature rises due to heating, the next section is the preheating section R2, where the temperature is almost constant, the next section is the reflow (main heating) section R3, and the final section is the cooling section R4.

[0020] The temperature rise section R1 is the period during which the board is heated from room temperature to the preheat section R2 (e.g., 150°C to 170°C). The preheat section R2 is a period during which isothermal heating is performed, for example, to activate the flux, remove oxide films from the electrodes and solder powder surfaces, and eliminate uneven heating of the printed wiring board. The reflow section R3 (e.g., peak temperature of 220°C to 240°C) is the period during which the solder melts, the bond is completed, and degassing is performed. Even after the preheat section R2, uneven temperature rise still exists in the reflow section R3, so heating to a temperature exceeding the melting point of the solder is required. The final cooling section R4 is the period during which the printed wiring board is rapidly cooled to form the solder composition. Note that in the case of lead-free solder, the temperature in the reflow section R3 is even higher (e.g., 240°C to 260°C).

[0021] In Figure 2, curve 1 shows an example of a temperature profile for lead-free solder. An example of a temperature profile for Sn-Pb eutectic solder is shown by curve 2. Because the melting point of lead-free solder is higher than that of eutectic solder, the set temperatures in preheat section R2 and reflow section R3 are set higher than those for eutectic solder.

[0022] In the reflow soldering equipment shown in FIG. 1, the temperature control of the heating section R1 in FIG. 2 is mainly handled by zones Z1 and Z2. The temperature control of the preheating section R2 is mainly handled by zones Z3, Z4, and Z5. The temperature control of the reflow section R3 is handled by zones Z6 and Z7. The temperature control of the cooling section R4 is handled by zones Z8 and Z9. The decompression zone Z7 performs a degassing process on the molten solder joint. Note that the decompression zone Z7 does not have to be located immediately before the cooling zone, and may be located anywhere within the heating zone other than immediately before the cooling zone.

[0023] An example of the depressurized zone Z7 is shown in Fig. 3. Fig. 3 is a cross-sectional view of the depressurized zone Z7 cut in directions (y and z directions) perpendicular to the transport direction (x direction) of the substrate W. The depressurized zone Z7 has a box-shaped metal housing 11 and an upper lid 12 that closes the upper opening of the housing 11. The upper lid 12 can be opened and closed freely so as to expose the upper opening of the housing 11.

[0024] The substrate W is transported through the decompression zone Z7 by a transport chain 104. A heater 13 is provided above the placement area of ​​the substrate W, and the heater 13 heats the substrate W to maintain the solder in a molten state. An upper rectifying plate 14 having an upper air vent is provided above the heater 13 above the placement area of ​​the substrate W. A lower rectifying plate 15 having a lower air vent is provided below the placement area of ​​the substrate W. The upper rectifying plate 14 and the lower rectifying plate 15 are rectangular and have an area approximately equal to or larger than the placement area of ​​the substrate W. The upper rectifying plate 14 and the lower rectifying plate 15 are, for example, perforated plates with numerous small holes or slits formed in a metal plate. Note that in Figure 3, the substrate outlet formed on the rear surface 22 of the housing 11 is not shown.

[0025] 4 is a perspective view of the housing 11 with the top lid 12 removed. The housing 11 has a front surface 21 and a rear surface 22 that are perpendicular to the transport direction of the substrate W, two side surfaces 23 and 24 that are parallel to the transport direction, and a bottom surface 25. A substrate inlet 26 is formed in the front surface 21 of the housing 11, and a substrate outlet 27 is formed in the rear surface 22 of the housing 11. The substrate inlet 26 and the substrate outlet 27 are configured to be able to be opened and closed freely by gate valves (not shown).

[0026] A vacuum hole 28 is formed in the bottom surface 25 of the housing 11, and an atmosphere vent hole 29 is formed in the side surface 23 of the housing 11. Furthermore, holes for attaching a chain drive transmission shaft may be formed in the side surfaces 23 and 24. A vacuum pump is connected to the vacuum hole 28 via piping. A nitrogen gas supply source is connected to the atmosphere vent hole 29 via piping. Instead of nitrogen gas, the atmospheric gas within the furnace body may be introduced into the reduced pressure zone Z7, or a mixture of nitrogen gas and the atmospheric gas within the furnace body may be introduced into the reduced pressure zone Z7. A controller controls the start and stop of the vacuum operation and the atmosphere vent operation.

[0027] Furthermore, a shielding member 30 is provided facing the vacuum hole 28 and substantially parallel to the bottom surface 25. The shielding member 30 is provided, for example, so as to form substantially the same plane as the lower rectifying plate 15. For example, the shielding member 30 is formed of a metal plate attached to the lower rectifying plate 15. The shielding member 30 is a plate-shaped member of a predetermined size. It is desirable that the size of the shielding member 30 (width direction in FIG. 3) be larger than the diameter of the vacuum hole 28. For example, if the hole diameter is 50 mm, it is desirable that the shielding member 30 be approximately 100 mm. The depth direction depends on the size of the decompression zone Z7 and is, for example, approximately 500 to 600 mm. The shielding member 30 may also be disposed below the lower rectifying plate 15.

[0028] In Figure 3, solid arrows indicate the flow of internal gas during evacuation. When the vacuum pump is activated, the internal gas in the depressurized zone Z7 is sucked through the evacuation holes 28. The internal gas is guided to the evacuation holes 28 through small holes or slits in the lower straightening plate 15. This generates a downforce that holds the substrate W downward, preventing the substrate W from vibrating and resulting in poor soldering during evacuation. In this case, the shielding member 30 is positioned opposite the evacuation holes 28, slowing the flow of internal gas and further suppressing vibration of the substrate W. Furthermore, when evacuation is performed, the vicinity of the workpiece W is first evacuated, followed by the space enclosed by the atmospheric vent holes 29 and the shielding member 31. This allows for a consistent gas flow within the depressurized zone Z7 (evacuation can be performed in the order of the arrows). Stability can be achieved by creating the same flow each time.

[0029] Furthermore, a shielding member 31 is provided so as to stand upright from the shielding member 30, facing the atmosphere vent hole 29 and substantially parallel to the side surface 23. The upper end of the shielding member 31 abuts against the end surface of the upper flow straightening plate 14. The shielding member 31 is a plate-shaped member of a predetermined size. As an example, the size of the shielding member 31 (height direction in FIG. 3) is about 30 to 50 mm from the upper cover 12, and its depth direction depends on the size of the decompression zone Z7, and is, for example, about 500 to 600 mm.

[0030] In Figure 3, the dashed arrows indicate the flow of internal gas during the atmosphere release operation. During the atmosphere release operation, nitrogen gas or the like is introduced into the decompression zone Z7 through the atmosphere release hole 29. The nitrogen gas flows downward toward the substrate W through the small holes or slits in the upper straightening plate 14. This generates a downforce that holds the substrate W downward, preventing the substrate W from vibrating and resulting in poor soldering during the atmosphere release operation. In this case, by providing the shielding member 31 opposite the atmosphere release hole 29, the amount of nitrogen gas flowing directly toward the substrate W can be reduced, further suppressing vibration of the substrate W. Furthermore, during the atmosphere release operation, nitrogen gas is released from the atmosphere release hole 29. Without the shielding member 31, nitrogen gas would be sprayed directly onto the workpiece W, potentially causing components on the workpiece W to fly off. The shielding member 31 can suppress such effects.

[0031] In this way, during the evacuation operation and the atmosphere release operation, it is possible to prevent the board W from vibrating due to the flow of gas within the reduced pressure zone Z7, thereby reducing the risk of defective soldering.

[0032] In the above-described reflow apparatus, there are transfer sections where the transport chains are interrupted at the entrance side of the decompression zone Z7 (between the transport chains 103 and 104) and at the exit side of the decompression zone Z7 (between the transport chains 104 and 105). Therefore, there is a problem that the substrates W are not transported smoothly in the transfer sections, causing the substrates W to stagnate. To solve this problem, an additional transport device (hereinafter referred to as a pusher) is provided in the present invention.

[0033] Fig. 5 is a perspective view illustrating a pusher in one embodiment, and Fig. 6 is an enlarged perspective view of the tip portion of the pusher. The pusher has pusher rods 42, 43, 142, and 143 attached to conveyor rails 41 and 141, respectively, for guiding a conveyor chain (not shown). These pusher rods are, for example, hollow. The lengths of pusher rods 42 and 43 and pusher rods 142 and 143 are approximately equal.

[0034] The pushers (the total length of the pusher rods 42 and 142, and the total length of the pusher rods 43 and 143) are longer than the distance from the entrance of the throat portion 109 on the entrance side of the reflow soldering apparatus shown in Fig. 1 to the entrance of the reduced pressure zone Z7. The length of the pusher rods 42 and 43 is equal to or greater than the distance from the entrance of the throat portion 109 to the exit side of the throat portion 109. For example, the length of the pusher rods 42 and 43 is equal to or greater than the length of the throat portion 109 plus the lengths required for mounting a rotation drive unit, a rotation-linear motion conversion mechanism, and a position switching mechanism, which will be described later.

[0035] The transport conveyor rails 41 and 141 are laid parallel to each other in the transport direction (x direction), and have transport chain storage sections recessed inward on opposing sides. The pusher rod 42 is slidably attached to pipe guides 44a and 44b provided on the outer side (non-opposing side) of the transport conveyor rail 41. One end of the pusher rod 42 is attached to a rotary drive unit (hereinafter referred to as a rotary actuator) 46, and the rotary actuator 46 enables the pusher rod 42 to rotate clockwise and counterclockwise around its axis.

[0036] The pusher rod 142 is slidably attached to pipe guides 144a and 144b provided on the outer side surfaces (non-facing side surfaces) of the transport conveyor rail 141. One end of the pusher rod 142 is attached to a rotary actuator 146, which enables the pusher rod 142 to rotate clockwise and counterclockwise around its axis.

[0037] The other ends of pusher rods 42 and 142 are connected to one ends of pusher rods 43 and 143 via position switching mechanisms 47 and 147. Position switching mechanisms 47 and 147 connect both pusher rods 42 and 142 located on the side of transport conveyor rails 41 and 141 and pusher rods 43 and 143 located on the top surfaces of transport conveyor rails 41 and 141 so that they rotate integrally.

[0038] FIG. 7 shows a schematic diagram of an example of the position switching mechanism 47. Four gears 51a, 51b, 51c, and 51d are housed in a case 50 attached along the outer surface and top surface of the conveyor rail 41 (shown by the two-dot chain line), and are meshed with each other. The lowest gear 51a, located on the side of the conveyor rail 41, is rotated by the pusher rod 42. The rotation of gear 51a is transmitted to the highest gear 51d, located on the top surface of the conveyor rail 41, via gears 51b and 51c. Gears 51a and 51d rotate at a 1:1 ratio. Gear 51d is attached to one end of the pusher rod 43, and gear 51a (pusher rod 42) and gear 51d (pusher rod 43) rotate together. The position switching mechanism 147 has a similar configuration to the position switching mechanism 47.

[0039] Support parts 52 are provided to hold one end sides of the transport conveyor rails 41 and 141 at a predetermined interval in the y direction. Rotary actuators 46 and 146 are attached to the support parts 52 on one end sides of the pusher rods 42 and 142. One end of the support part 52 is attached to a slider 54 of a single-axis actuator 53 serving as a rotary-to-linear motion conversion mechanism. The other end of the support part 52 is attached to the slider 154.

[0040] The single-axis actuator 53 is a mechanism that converts the rotation of the servo motor 55 into linear motion of the sliders 54 and 154. The sliders 54 and 154 move linearly in a direction parallel to the extension direction of the transport conveyor rail 41 (+ / -x direction). Note that a mechanism other than the single-axis actuator may be used as the rotation-to-linear motion conversion mechanism. By controlling the servo motor 55, the speed and direction of the sliding motion of the pusher rods 42, 43, 142, 143 can be controlled as desired.

[0041] Rotation of the servo motor 55 of the single-axis actuator 53 causes the sliders 54 and 154 to move linearly in the same direction at the same speed, resulting in the pusher rods 42 and 142 sliding in the same direction at the same speed. Also, the direction and amount of sliding movement of the pusher rods 43 and 143, which are connected to the pusher rods 42 and 142 via position switching mechanisms 47 and 147, are made equal. One of the transport conveyor rails 41 and 141 is movable in parallel in the y direction in accordance with the width of the board W, and the pusher rod attached to one of the transport conveyor rails 41 and 141 is also movable in parallel in the y direction.

[0042] The pusher rods 42, 43, 142, and 143 are slidable in the transport direction (x direction) of the substrate W and in the opposite direction to the transport direction (-x direction). As will be described later, the substrate is transported by sliding in the x direction, and returned to its original position by sliding in the -x direction. The speed of the sliding movement of the pusher rods 42, 43, 142, and 143 in the x direction is set to be equal to or slightly faster than the transport speed of the substrate. The sliding movement of the pusher rods 42, 43, 142, and 143 in the -x direction is set to be faster than the transport speed of the substrate, and the time required for the return movement is short.

[0043] The reason why position switching mechanisms 47 and 147 are necessary will be explained. As will be described later, push-out portions for pushing and transporting substrates are attached to the tip portions of pusher rods 43 and 143. Considering the positional relationship in which the push-out portions abut against the rear ends of the substrates to push them, pusher rods 42, 43, 142, and 143 are desirably provided on the upper surfaces of transport conveyor rails 41 and 141. However, because throat portion 109 functions as a sealing portion, the free space above the transport surface of substrate W is very narrow, for example, 30 mm.

[0044] 8A and 8B are schematic diagrams of a cross section orthogonal to the x-direction of the reflow device, with Fig. 8A showing a cross section of the throat portion 109 and Fig. 8B showing a cross section of a zone after the position switching mechanisms 47 and 147, such as zone Z4. The position switching mechanisms 47 and 147 are disposed at any position between the outlet of the throat portion 109 and a position slightly rearward of the entrance of the decompression zone Z7.

[0045] The throat portion 109 has an opening with a height as low as possible to stabilize the oxygen concentration in the furnace. Therefore, as shown in FIG. 8A , the empty space above the conveyor rails 41 and 141 in the throat portion 109 is low, making it difficult to place the pusher rods 42 and 142. Therefore, the pusher rods 42 and 142 are slidably disposed on the outer side surfaces of the conveyor rails 41 and 141. The conveyor chains 103 and 203 are disposed in storage compartments formed in the conveyor rails 41 and 141, respectively. The conveyor chains 103 and 203 have link plates connecting the rollers, and the substrates W are placed on pins protruding from the link plates toward the conveying surface and transported. Although not shown, guides supporting the rollers of the conveyor chains 103 and 203 are disposed within the conveyor rails 41 and 141.

[0046] As shown in Figure 8B, in a zone of the heating furnace configuration, for example, zone Z4, there is an empty space of sufficient height to provide pusher rods 43 and 143 on the upper surfaces of the transport conveyor rails 41 and 141. Therefore, the pusher rods 43 and 143 can be provided on the upper surfaces of the transport conveyor rails 41 and 141. Since the attachment positions of the pusher rods relative to the transport conveyor rails 41 and 141 change from the side to the upper surface in this way, position switching mechanisms 47 and 147 are provided.

[0047] A first push-out unit 56 is attached to the tip of pusher rod 43, and a push-out unit 156 is attached to the tip of pusher rod 143 opposite push-out unit 56 in the y direction. Figures 5 and 6 show two substrates W1 and W2 being transported at a predetermined interval. There may be other substrates transported at predetermined intervals before and after these substrates, but for simplicity of explanation, an example in which two substrates W1 and W2 are transported will be described.

[0048] The pushers 56 and 156 are rectangular plates with one side fixed to the pusher rods 43 and 143, respectively, so that the rectangular plate protrudes toward the transport surface of the substrate W1. The pushers 56 and 156 move up and down by rotation of the rotary actuators 46 and 146 (pusher rods 43 and 143), switching between a standby position (upper position) and a push position (lower position). In the standby position, the plate surfaces of the pushers 56 and 156 are parallel to the transport surface of the substrate, and when the pushers 56 and 156 slide in the x direction, the plate surfaces do not come into contact with the substrate. In the push position, the plate surfaces of the pushers 56 and 156 intersect with the transport surface of the substrate, and when the pushers 56 and 156 slide in the x direction, the front ends of the plate surfaces come into contact with the substrate.

[0049] The second push-out portions 57 and 157 are provided behind the first push-out portions 56 and 156. The distance between the front ends of the first push-out portions 56 and 156 that contact the substrate and the front ends of the second push-out portions 57 and 157 that contact the substrate is slightly longer than the lengths of the front and rear ends of the substrates. In other words, when the substrates W1 and W2 are present at a predetermined distance, when the front ends of the first push-out portions 56 and 156 contact the rear end of the front substrate W1, the front ends of the second push-out portions 57 and 157 contact the rear end of the rear substrate W2. The distance between the first push-out portions 56 and 156 and the second push-out portions 57 and 157 can be adjusted as necessary.

[0050] The second pushers 57 and 157 are rod-shaped, with their bases fixed at predetermined positions at the aforementioned distance rearward from the pushers 56 and 156, and their tips protruding toward the substrate transport surface. The pushers 57 and 157 move up and down by rotation of the rotary actuators 46 and 146 (pusher rods 43 and 143), switching between a standby position (upper position) and a push position (lower position). At the standby position, the tips of the pushers 57 and 157 are parallel to the substrate transport surface, and when the pushers 57 and 157 slide in the x direction, the tips do not come into contact with the substrate. At the push position, when the pushers 57 and 157 slide in the x direction, the front ends of the pushers 57 and 157 intersect the substrate transport surface and come into contact with the substrate.

[0051] The push-out units 56 and 156 switch between the standby position and the push position in synchronization. In Figure 6, the decompression zone Z7 is indicated by a virtual line (two-dot chain line). The figure shows a state in which the rear end of the substrate W1 in the decompression zone Z7 approaches the front ends of the push-out units 56 and 156, and the rear end of the substrate W2 in the previous zone Z6 abuts the front ends of the push-out units 57 and 157.

[0052] From this state, the forward sliding motion of the pusher's first push-out portions 56 and 156 and second push-out portions 57 and 157 pushes substrates W1 and W2 forward a predetermined distance, for example, approximately half the length of the substrate in the x direction. This motion prevents substrates W1 and W2 from becoming stuck at the transfer point where the transport chain is interrupted. The distance of the sliding motion is set to a length that allows the substrates to get over the joint in the transport chain and prevents them from becoming stuck.

[0053] The configuration of the control device that controls the operation of the pusher described above is shown in Figure 9. A control panel 161 includes a PLC (programmable logic controller) 162 and a driver 163. The PLC 162 is a computer in which the programs required for automatic control of the pusher are written.

[0054] The output of the PLC 162 is supplied to a driver 163, and the output of the driver 163 is supplied to the servo motor 55 and a direction control device 164. The output of the initial position confirmation sensor Sx0 is supplied to the servo motor 55. The direction control device 164 controls the rotary actuators 46 and 146. Furthermore, a plurality of sensors Sx1 to Sx5 for detecting substrates are provided on the substrate transport path, and detection signals of these sensors Sx1 to Sx5 are supplied to the control panel 161. Photosensors, magnetic sensors, etc. can be used as the sensors Sx1 to Sx5.

[0055] FIG. 10 is a schematic diagram used to explain the control operation. FIG. 10 is a plan view corresponding to the perspective view of FIG. 6, showing one side from the center of the transport path near the depressurized zone Z7. The following description of one side also applies to the other side (not shown), but to avoid redundancy, the description of the other side is omitted. FIG. 10 also shows a state in which substrate W1 is located in depressurized zone Z7 and the following substrate W2 is located in zone Z6. Furthermore, the reference symbols shown in FIG. 10 indicate the following parts.

[0056] T1: Front end position of board W1, B1: Rear end position of board W1 T2: Front end position of board W2, B2: Rear end position of board W2 56t: Front end of extrusion part 56 (part that pushes the board) 56r: rear end of extrusion portion 56 57t: Front end of extrusion part 57 (part that pushes the board)

[0057] The detection operation of each sensor is shown below. Sensor Sx1 OFF→ON: Board arrival detection Sensor Sx1 ON→OFF: To avoid collision with the circuit board when the front end 57t of the extrusion part 57 rotates Sensor Sx2 OFF→ON: Pusher operation trigger sensor Sensor Sx3 ON→OFF: Checks the rear end of the board. This sensor triggers the gate valve to close and the pusher to return. Sensor Sx4 ON: Sensor that detects the maximum position reached within the decompression zone Z7 Sensor Sx5 ON→OFF: To avoid collision with the board when the gate valve is operating

[0058] The operation of one embodiment will be described with reference to the layout diagram of Fig. 10 and the graph of Fig. 11. Fig. 11 is a graph in which the horizontal axis represents time and the vertical axis represents position in the x direction. The initial position (0) corresponds to the position of sensor Sx2.

[0059] When the front end position T1 of substrate W1 coincides with the initial position at the first time t1, sensor Sx2 turns ON. This is the state in which substrate W1 is present at the position of substrate W2 in FIG. 10. The position of substrate W2 is on the - side (rear side) of substrate W1. At the initial position, rotary actuator 46 operates, pusher rods 42 and 43 rotate, and push-out units 56 and 57 move down, making it possible to push substrate W1. In other words, push-out units 56 and 57 move from the standby position to the push position.

[0060] At time t2, the rear end position of substrate W1 and the front end position of push-out section 57 coincide, and thereafter substrate W1 is transported by transport chain 103 and push-out section 57. Because there is a gap between push-out section 57 and the rear end of substrate W1, the sliding motion of push-out section 57 is temporarily made faster than the transport speed of transport chain 103, and at time t2, the front end of push-out section 57 abuts against the rear end of substrate W1. In Figure 11, changes in front end position T1 and rear end position B1 of substrate W1 are shown by lines Gt1 and Gr1, and changes in front end position T2 and rear end position B2 of substrate W2 are shown by dashed lines Gt2 and Gr2.

[0061] After time t2, a pushing force from push-out section 57 is applied to substrate W1, so that substrate W1 is reliably sent into depressurized zone Z7 without stagnation, even in the transfer section where no transport chain exists between transport chains 103 and 104. Then, at time t3, when the rear end of substrate W1 passes sensor Sx3, sensor Sx3 turns OFF. After time t3, substrate W1 is present in depressurized zone Z7.

[0062] At time t3, the rotary actuator 46 operates, the pusher rods 42 and 43 rotate, and the push-out portions 56 and 57 rise, moving from the push position to the standby position. The pusher rods 42 and 43 then slide back to their original positions. The speed at which they return is higher than the speed at which they push the substrate. In the original position, the front end 56t of the push-out portion 56 is located slightly behind the rear end position B1 of the substrate W1.

[0063] The period indicated by t4 is the time during which substrate W1 is stationary in decompression zone Z7 and degassing and other processes are performed. That is, the gate valve is closed, followed by vacuuming, then opening to the atmosphere, and then the gate valve is opened. During this period t4, substrate W2 is transported by transport chain 103, and the gap between substrates W1 and W2 gradually narrows. During period t4, push-out units 56 and 57 are stationary in their original positions.

[0064] Time t5 is the time immediately after the gate valve of decompression zone Z7 is opened. FIG. 10 shows the state immediately before time t5. Just before time t5, the push-out units 56 and 57 start sliding. At time t5, the sensor Sx2 turns ON, the pusher rods 42 and 43 rotate, and the push-out units 56 and 57 descend to a position where they can push the substrate. In other words, the push-out units 56 and 57 change from the standby position to the push position.

[0065] At time t6, which is the same as time t5, a temporary acceleration of the slide speed causes the front end 56t of the push-out section 56 to coincide with the rear end position B1 of the substrate W1, and the substrate W1 is transported by the push-out section 56 and the transport chain 104. After time t6, a pushing force of the push-out section 56 is applied to the substrate W1, so that even in the transfer section between the transport chain 104 and the transport chain 105 where there is no transport chain, the substrate W1 is reliably sent to the next zone Z8 without stagnation.

[0066] At time t7, which is the same as time t5, a temporary acceleration of the slide speed causes the front end 57t of the push-out section 57 to coincide with the rear end position B2 of substrate W2, and substrate W2 is transported by push-out section 57 and transport chain 103. After time t7, a pushing force of push-out section 57 is applied to substrate W2, so that even in the transfer section between transport chain 103 and transport chain 104 where no transport chain exists, substrate W2 is reliably sent to the next decompression zone Z7 without stagnation.

[0067] The above-described embodiment is a reflow apparatus configured to degas in a reduced pressure zone. In such a configuration, degassing (evacuating and opening to the atmosphere) may not be performed in the reduced pressure zone, and a simple heating process may be performed without closing the gate valve. In this case, the apparatus can operate as an existing continuous transfer reflow apparatus, improving versatility.

[0068] Although specific embodiments of the present invention have been described above, they are not limited to the above-described embodiments and various modifications are possible based on the technical concept of the present invention. For example, although the pusher has two parallel pusher rods, it may have a single pusher rod. Furthermore, the present invention is not limited to printed circuit boards, but can also be applied to the reflow of flexible boards, boards formed by bonding rigid and flexible boards, and rigid-flex boards that combine these. The present invention can also be applied to reflow apparatuses with a single heating furnace (one zone). The configurations, methods, processes, shapes, materials, and values ​​described in the above-described embodiments are merely examples, and different configurations, methods, processes, shapes, materials, and values ​​may be used as needed. The configurations, methods, processes, shapes, materials, and values ​​described in the above-described embodiments can be combined with each other without departing from the spirit of the present invention. [Explanation of symbols]

[0069] 101... Reflow device, 103, 104, 105... Conveyor chain, 109, 110... Throat section, Z7... Depressurization zone, W, W1, W2... Board, 41, 141... Conveyor rail, 42, 142, 43, 143... Pusher rod, 46, 146... Rotary actuator, 47, 147... Position switching mechanism, 53... Single-axis actuator, 55... Servo motor, 56, 156... Push-out section, 57, 157... Push-out section, 161... Control panel, Sx1 to Sx5... Sensor

Claims

1. In a conveying and heating device in which a heating zone, a decompression zone, and a cooling zone are arranged in this order, a conveyor is provided in each of the heating zone, the decompression zone, and the cooling zone; A conveying and heating device equipped with a pusher that pushes out the workpiece toward the entrance side of the decompression zone.

2. The pusher has a pusher rod that is slidable in at least one workpiece conveying direction, and two push-out portions attached to the pusher rod, 2. A conveying and heating device as described in claim 1, wherein the workpiece is pushed from the heating zone to the decompression zone by one push-out section and the workpiece is pushed from the decompression zone to the cooling zone by the other push-out section almost simultaneously.

3. The pusher rod is rotatable about an axis, After the pusher rod rotates, the two pushing parts are located at the pushing position; 3. The conveying and heating device according to claim 2, wherein after the workpiece is pushed out, the pusher rod is rotated in the reverse direction so that the two push-out portions are positioned at standby positions.

4. a throat portion is provided on the inlet side of the heating zone, 4. The conveying and heating device according to claim 1, wherein the pusher rod is installed at different positions in the throat portion and the heating zone.

5. The pusher rod is provided on the side of the conveyor rail at the throat portion, 5. The conveying and heating device according to claim 4, wherein the heating zone after the throat portion is provided on the upper surface of the conveyor rail.

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