JP2005199286A - Warp preventing apparatus and method for printed circuit board in reflow device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for preventing a warp of a printed circuit board in a reflow device, that can bring support pins into point contact with the reverse side of the printed circuit board so as to minimize a contact area without using a large-scale warp preventing mechanism and that can easily and surely prevent the printed circuit board from warping. <P>SOLUTION: For the purpose of preventing interference on electronic components 80 already mounted on the reverse side of the printed circuit board P, at the time of its transportation inside a reflow device 2, there are arranged the support pins 36 (stopper pins 36a and support pins 36b) in an arbitrary position coordinate. In addition, the support pins 36 (support pins 36b) are brought into point contact with the reverse side of the printed circuit board P so that the contact area is minimized. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, after mounting a surface mount electronic component on a pad portion on a printed circuit board on which paste-like solder has been printed in advance, the printed circuit board is transported, and the paste-like solder is heated and melted and solidified to be soldered. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board warpage prevention apparatus and a warpage prevention method for a reflow apparatus to be performed.

  Conventionally, as this type of reflow apparatus, for example, the configuration shown in FIGS. 19 and 20 is generally used. The apparatus configuration includes a heating zone F including a heater 4 and a fan 5 for heating a printed circuit board P, and a print. There is a cooling zone G consisting of a fan 6 for cooling the substrate P. Each zone F, G is arranged in series with respect to the conveyance direction A of the printed circuit board P and in two stages above and below the conveyance height of the printed circuit board P. It is.

  As a means for transporting the printed circuit board P carried in from the previous process to each of the zones F and G at a constant speed, there are a pair of left and right endless transport chains 7 in the transport direction A. These transport chains In general, both end portions of the printed circuit board P are placed on a connecting pin (not shown) on the inner surface of the printed circuit board 7, and the printed circuit board P is transported by rotating the transport chain 7.

  As the function of each device configuration from the viewpoint of the soldering action, the heating zone F activates the flux component contained in the solder paste to improve the solderability, and at the same time, preheats to prevent component destruction due to a sudden rise in temperature. It can be divided into a zone and a soldering zone that heats and melts the solder to a melting point or higher. On the other hand, the cooling zone G is an area that is arranged on the downstream side of the heating zone F and solidifies solder melted in the soldering zone at once.

  The furnace temperature of the reflow apparatus is as high as 230 to 245 ° C., and the softening temperature of glass epoxy generally used as a printed board material is around 120 ° C., so only the both side edges of the printed board P are supported. As shown in FIG. 21, the printed circuit board P warps downward as a result of the conveyance structure by the conveyance chain 7 and the weight of the printed circuit board P and the weight of the electronic component 80 mounted on the printed circuit board P.

  If the printed circuit board P is warped, poor solder connection such as non-contact, residual stress in the solder connection part, and dropping of the printed circuit board P in the reflow apparatus are induced.

  In addition, due to the recent increase in functionality and reduction in thickness and size of electronic devices, it is difficult to follow high-density mounting of the printed circuit board P, thinning of the printed circuit board P itself, multi-sided substrate using V grooves and warping of the printed circuit board P. A wide variety of parts such as a bottom electrode part without a lead terminal such as a BGA (Ball Grid Array) has been widely used.

  Furthermore, lead-free solder that does not contain lead in solder has started to be used due to the harmfulness of lead contained in the solder to the human body, and general lead-free solder has a higher melting point than conventional eutectic solder containing lead, and reflow In the soldering process, there is a tendency that the warp of the printed circuit board P is further promoted by increasing the heater set temperature inside the reflow apparatus.

  Conventionally, the electronic component 80 mounted only on one side of the printed circuit board P is mounted and reflow soldering is performed as a mounting form (reflow soldering once, hereinafter referred to as single side reflow soldering). Is a method in which the printed circuit board P that has been reflow soldered once is turned over, surface mounted components are mounted on the opposite side, and reflow soldering is performed once again (reflow soldering twice, hereinafter referred to as double-sided reflow soldering) Say) is becoming mainstream.

  As shown in FIG. 22, as a printed circuit board warpage preventing device in a conventional reflow apparatus, the substantially central portion of the lower surface of the printed circuit board P on which the electronic component 80 is mounted is slidably contacted with a warp preventing chain 90. There is a configuration in which a warp prevention chain 90 is held by a warp prevention body 91 (see, for example, Patent Document 1).

Further, as a printed circuit board warpage preventing apparatus in another conventional reflow apparatus, as shown in FIG. 23, a pin mounting plate 93 having a large number of pin holes 93a is provided below a printed circuit board P on which an electronic component 80 is mounted. The backup pin 94 is mounted in the pin hole 93a of the pin mounting plate 93, and the pin mounting plate 93 is moved up and down by the actuator 95. When the printed circuit board P is intermittently moved and stopped, Some actuators 95 are actuated to raise the pin mounting plate 93 and support the printed circuit board P from the back with a backup pin 94 to prevent warping (see, for example, Patent Document 2).
JP-A-4-22572 (P.2-3, Fig. 3) JP-A-4-72693 (P.2-3, Fig. 1)

  However, in the printed circuit board warpage prevention device in the former conventional reflow apparatus described above, the back surface of the printed circuit board P is received by the line and the surface because of the prevention of warpage using the chain 90. There is a problem that it is difficult to bring the chain 90 into contact with the printed circuit board P so as not to interfere with the mounting components on the back surface of the printed circuit board P that is reflow soldered on both sides.

  Further, in the printed circuit board warpage prevention device in the latter conventional reflow apparatus described above, a large-scale warpage prevention mechanism is required, such as a structure in which the pin mounting plate 93 is raised by the actuator 95, and the printed circuit board. Even if the back-up pin 94 is brought into contact with the back surface of P, there is a problem in that it is difficult to uniformly apply a desired amount of heat to the printed circuit board P because heat is taken away by the large warpage prevention mechanism.

  This phenomenon is a major problem when using lead-free solder with a high melting point. Lead-free solder has a high melting point and a small gap between the component heat resistance temperature and the solder melting point. Need to be small.

  The present invention has been made to solve the above-mentioned problems, and a first object of the present invention is to provide a support pin so as to make the contact area as small as possible without using a large warp prevention mechanism. An object of the present invention is to provide an apparatus for preventing warping of a printed circuit board in a reflow apparatus that can make point contact with the back surface of the printed circuit board and easily and reliably prevent warping of the printed circuit board.

  The second object of the present invention is to provide a method for preventing warping of a printed circuit board in a reflow apparatus capable of automatically preventing warping of the printed circuit board during transport in reflow soldering of the printed circuit board having components mounted on the back surface. Is to provide.

  In order to achieve the above first object, the printed circuit board warpage prevention device in the reflow apparatus according to the present invention places the printed circuit board on which the electronic component is mounted on the conveyance chain at both end portions in the width direction, A printed circuit board warpage prevention device in a reflow device that heats and solders a printed circuit board while transporting the printed circuit board by rotation of the transport chain, and is disposed between the transport chains in parallel with the transport chain. A chain for preventing warpage that rotates in the direction of conveyance of the printed circuit board, a number of support pins that can be raised and lowered on the warpage prevention chain and supporting the printed circuit board from the back, and the support pins at a plurality of stages at an arbitrary pitch Support pin lifting mechanism for lifting and lowering, and a support pin initial setting machine for setting the support pin lifted and lowered by the support pin lifting mechanism to the initial position Characterized in that a part.

  With this configuration, when the printed circuit board is transported by the reflow apparatus, the support pins are arranged at arbitrary position coordinates so as not to interfere with the electronic components already mounted on the back surface of the printed circuit board, and the support pins are made as small as possible. Can be brought into point contact with the back surface of the printed circuit board, and warping of the printed circuit board can be easily and reliably prevented.

  In addition, the warp prevention chain and the support pins themselves are as compact and small in heat capacity as possible so as not to impede heat transfer from the heater to the printed circuit board. It is also effective when lead-free solder having a high melting point is used.

  Further, the printed circuit board warpage preventing apparatus in the reflow apparatus according to the present invention is the above-described printed circuit board warpage preventing apparatus in the reflow apparatus according to the present invention. A large number of holding brackets are provided, and these holding brackets have two upper and lower plate portions, and each of these plate portions has an opening portion, and inside each of these opening portions is a pair. The support pin has a plurality of spherical locking portions at predetermined intervals in the axial direction thereof, and the support pin is engaged with the opening in a state of passing through the opening. The holding bracket is held by holding the upper and lower portions of any one of the stoppers with a holding spring.

  With such a configuration, the support pin is held by the holding bracket in a state where the support pin penetrates the opening of the plate portion of the holding bracket. When the support pin is moved up and down by an external force such as a cam, the holding spring is bent and the locking part passes through the opening, and either the upper or lower locking part is in the opening. Positioned, the upper and lower parts of the locking part are held by the bracket by being sandwiched by a pair of holding springs. When the printed circuit board is transported by the reflow device, the electronics already mounted on the back surface of the printed circuit board The support pins can be brought into point contact without interfering with the parts.

  Further, the printed circuit board warpage preventing device in the reflow device according to the present invention is the above-described printed circuit board warpage preventing device in the reflow device according to the present invention, wherein the support pin lifting mechanism includes a stopper height cam and a support height. A cam for a stopper, a cam for a free height, a cam for a stopper height, a cam for a support height and a rotation driving means for rotating the cam for a free height, By rotating the support height cam and the free height cam by the rotation drive means, the stopper height cam is set to the stopper height position where one of the support pins contacts the front end surface of the printed circuit board. The support height cam sets the other one of the support pins to the support height position where it abuts the back surface of the printed circuit board, and the free height cam sets the other one of the support pins. Characterized in that the to set the free height position that ensures a height that does not interfere with the electronic components mounted on the rear surface of the printed board.

  With this configuration, the stopper height cam, the support height cam, and the free height cam are rotated by the rotation driving means, so that the stopper height cam causes one of the support pins to be placed on the front end surface of the printed circuit board. Set the stopper height to be in contact to prevent misalignment when transporting the printed circuit board, and the support height cam is located at the support height position where the other support pin abuts the back surface of the printed circuit board. Set to prevent warping, and the free height cam has a free height position that ensures that the other one of the support pins does not interfere with the electronic components mounted on the back side of the printed circuit board Can be set.

  Further, the printed circuit board warpage prevention device in the reflow apparatus according to the present invention is the above-described printed circuit board warpage prevention apparatus in the reflow device according to the present invention, wherein the support pin initial setting mechanism section has an upper surface in an upper stage, a middle stage, and a lower stage. It has an initial setting bracket that has been processed to three levels of height, and this initial setting bracket is at the same relative position as the free height position in the upper stage, the support height position in the middle stage, and the stopper height position in the lower stage. It is adjusted by the height adjustment mechanism so that the support pin slides on the slope of the initial setting bracket by the movement of the warp prevention chain, so that the support pin is free height position, support height position, stopper height Each position is initially set.

  With this configuration, the support pin slides on the slope of the initial setting bracket by the movement of the warp prevention chain, and the support pin is initialized to the free height position, the support height position, and the stopper height position. In addition, the support pins can come into contact with the back surface of the printed circuit board so as to avoid electronic components mounted on the back surface of the printed circuit board.

  Further, the printed circuit board warpage preventing apparatus in the reflow apparatus according to the present invention is the above-described printed circuit board warpage preventing apparatus in the reflow apparatus according to the present invention, wherein the width of the pair of transport chains is changed by the transport chain width changing means. The warp prevention chain is moved and adjusted in a direction perpendicular to the conveyance direction of the printed circuit board by the movement prevention means of the warp prevention chain, and the support pin lifting mechanism is moved by the movement adjustment means of the support pin lifting mechanism. The movement adjustment in the direction perpendicular to the conveyance direction of the printed circuit board is performed.

  With this configuration, by changing the width of the pair of transport chains by the transport chain width changing means, it is possible to transport printed boards having different width dimensions, and the movement of the warp preventing chain by the warp preventing chain movement adjusting means. By making adjustments and adjusting the movement of the support pin lifting mechanism with the support pin lifting mechanism movement adjustment means, it is possible to easily set the placement of the support pins according to the component mounting on the back side of the printed circuit board, the board shape, etc. Thus, it is possible to facilitate reflow soldering of a wide variety of printed circuit boards that perform double-sided reflow soldering.

  Further, the printed circuit board warpage prevention device in the reflow apparatus according to the present invention is configured such that a printed circuit board on which electronic components are mounted is placed on a conveyance chain at both end portions in the width direction, and the printed circuit board is rotated by rotating the conveyance chain. A printed circuit board warpage prevention device in a reflow device that heats and solders a substrate while it is being transported, and is disposed between the transport chains in parallel to these transport chains and rotates in the transport direction of the printed circuit boards. It has a chain to prevent warping, and two types of support pins with different pin lengths are attached to the chain for warping so that they can be tilted by the hinge mechanism and alternately arranged in the direction of printed circuit board conveyance. It is characterized by.

  With this configuration, the state where the long support pin is tilted is the stopper height position, the state where the short support pin is tilted is the support height position, and the state where both support pins are not tilted is the free height position. Thus, the support pins can be brought into point contact with the back surface of the printed circuit board so as to make the contact area as small as possible, and warping of the printed circuit board can be easily and reliably prevented.

  In order to achieve the second object of the present invention, the printed circuit board warpage preventing method in the reflow apparatus according to the present invention is a reflow process in which a printed circuit board on which electronic components are mounted is heated and soldered. A method of preventing warping of a printed circuit board in an apparatus, wherein the printed circuit board is transported by rotation of a transport chain, and the warp prevention chain is rotated in synchronization with the travel of the transport chain. A plurality of support pins are lifted and lowered to a plurality of levels at an arbitrary pitch, and the printed circuit board is supported from the back side by the support pins to prevent the printed circuit board from being warped during the transport process of the reflow device. .

  Therefore, the support pins provided in the warp prevention chain are lifted and lowered to multiple levels at arbitrary pitches, and the printed circuit board is supported by the support pins from the back side, thereby preventing the printed circuit board from being warped during the transport process of the reflow device. It can be prevented automatically.

  Further, the printed circuit board warpage prevention method in the reflow apparatus according to the present invention is the above-described printed circuit board warpage prevention method in the reflow apparatus according to the present invention. Based on the pin arrangement information input in advance, considering the restrictions, the support pins are moved up and down, and the speed of the transport upstream conveyor and the timing of unloading the printed circuit board are controlled to automatically reflow the printed circuit board. It is characterized in that it is put into the inside.

  Therefore, the support pins can be automatically brought into contact with arbitrary coordinates on the back surface of the printed circuit board, and the printed circuit board can be automatically put into the reflow device by controlling the speed of the upstream conveyor and the transport timing. Can do. For this reason, it is possible to automatically produce a wide variety of printed circuit boards that perform double-sided reflow soldering, and to support double-sided reflow soldering using high-density printed circuit boards and lead-free solder, which are increasing in the future. It becomes possible.

  According to the printed circuit board warpage preventing device in the reflow apparatus according to the present invention, the support pins can be set to arbitrary position coordinates so as not to interfere with the electronic components already mounted on the back surface of the printed circuit board when the printed circuit board is conveyed by the reflow apparatus. The support pins can be placed in point contact with the back surface of the printed circuit board so that the contact area is as small as possible, and warping of the printed circuit board can be easily and reliably prevented.

  In addition, the warp prevention chain and the support pins themselves are as compact and small in heat capacity as possible without impeding the heat transfer from the heater to the printed circuit board, so that a desired amount of heat is uniformly applied from the heater to the printed circuit board. This is also effective when lead-free solder having a high melting point is used.

  Further, according to the printed circuit board warpage preventing device in the reflow device according to the present invention, the support pin penetrates through the opening of the plate portion of the holding bracket, for example, the upper and lower portions of the intermediate locking portion. When the support pin is lifted and lowered by an external force such as a cam while being held by the holding bracket by being sandwiched between the pair of holding springs, the holding spring is bent and the locking portion opens the opening. Passing, one of the upper and lower locking parts is located in the opening, and the upper and lower parts of the locking part are held by the pair of holding springs so that they are held by the bracket. When the printed circuit board is conveyed, the support pins can be brought into point contact without interfering with electronic components already mounted on the back surface of the printed circuit board.

  Further, according to the printed circuit board warpage preventing device in the reflow apparatus according to the present invention, the stopper height cam, the support height cam, and the free height cam are rotated by the rotation driving means, thereby the stopper height cam. The cam sets one of the support pins to a stopper height position that contacts the front end surface of the printed circuit board to prevent displacement during conveyance of the printed circuit board. One is set to the support height position that contacts the back side of the printed circuit board to prevent warping, and a free height cam is mounted on the back side of the printed circuit board with another one of the support pins. It can be set to a free height position that ensures a height that does not interfere with electronic components.

  Further, according to the printed circuit board warpage preventing device in the reflow apparatus according to the present invention, the support pin slides on the inclined surface of the initial setting bracket by the movement of the warp preventing chain so that the support pin is at the free height position and the support height. Since the initial position is set at each of the vertical position and the stopper height position, the support pin can come into contact with the back surface of the printed circuit board so as to avoid electronic components mounted on the back surface of the printed circuit board.

  Further, according to the printed circuit board warpage preventing device in the reflow apparatus according to the present invention, the width of the pair of transport chains is changed by the transport chain width changing means, thereby enabling the transport of the printed circuit boards having different width dimensions. The movement adjustment of the warp prevention chain is performed by the movement prevention chain movement adjusting means, and the movement adjustment of the support pin raising / lowering mechanism part is performed by the support pin raising / lowering mechanism movement adjustment means, so that the component mounting on the back side of the printed circuit board The arrangement of the support pins according to the shape or the like can be easily set, and the reflow soldering of a wide variety of printed circuit boards for performing the double-sided reflow soldering can be realized.

  Further, according to the printed circuit board warpage preventing device in the reflow apparatus according to the present invention, two types of support pins having different pin lengths can be tilted by the hinge mechanism on the warp preventing chain and alternately in the transport direction of the printed circuit board. When the long support pin is tilted, the state where the long support pin is tilted is the stopper height position, and when the short support pin is tilted is the support height position, both the support pins are not tilted. As a result, the support pin can be brought into point contact with the back surface of the printed circuit board so that the contact area becomes as small as possible, and warping of the printed circuit board can be easily and reliably prevented.

  Further, according to the method for preventing warpage of a printed circuit board in the reflow apparatus according to the present invention, the plurality of support pins provided in the warp prevention chain are moved up and down to a plurality of levels at an arbitrary pitch, and the printed circuit board is moved by the support pins. By supporting from the back side, it is possible to prevent the printed circuit board from warping during the transport process of the reflow apparatus.

  Further, according to the printed circuit board warpage preventing device in the reflow apparatus according to the present invention, the support pins can be automatically brought into contact with the arbitrary coordinates on the back surface of the printed circuit board, and the speed of the transport upstream conveyor and the transport timing can be set. By controlling, the printed circuit board can be automatically put into the reflow apparatus. For this reason, it is possible to automatically produce a wide variety of printed circuit boards that perform double-sided reflow soldering, and to support double-sided reflow soldering using high-density printed circuit boards and lead-free solder, which are increasing in the future. It becomes possible.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a schematic configuration explanatory view of a reflow apparatus provided with a printed circuit board warpage prevention apparatus (Embodiment 1) according to the present invention. Is mounted on the downstream side, and a printed circuit board storage device 3 for storing the printed circuit board P after completion of soldering by the reflow device 2 in a rack (not shown) is disposed on the downstream side.

  The reflow apparatus 2 has a heating zone F composed of a heater 4 and a fan 5 for heating the printed circuit board P, and a cooling zone G composed of a fan 6 for cooling the printed circuit board P. Each of the zones F and G is a conveyance direction of the printed circuit board P. Are arranged in two stages above and below the height of the printed board P in series.

  As a means for transporting the printed circuit board P carried from the previous process to each of the zones F and G at a constant speed, there are a pair of left and right endless transport chains 8b and 9b with respect to the transport direction A. Both end portions are placed on the connecting pins 10 on the inner surfaces of the transport chains 8b and 9b, and are transported by the rotational travel of the transport chains 8b and 9b.

  (C / V1) is a buffer conveyor that receives the printed circuit board P carried from the previous process, and can rotate at a constant speed and can be temporarily stopped. Further, in the reflow device 2, there is a buffer conveyor (C / V2) capable of transporting the printed circuit board P received from the buffer conveyor (C / V1) at a variable speed. This buffer conveyor (C / V2) is the reflow device 2 It relays at an appropriate timing to the internal transport chain device (C / V3).

  These three transport systems can input and output signals with each other, and can operate independently by signals from a control unit (not shown) in the reflow apparatus 2. The buffer conveyor (C / V1) includes a sensor S1 that detects the printed circuit board P carried into the inlet portion of the reflow device 2, a sensor S2 that outputs a deceleration signal when the printed circuit board P is detected, A sensor S3 for detecting the stop position is provided. The buffer conveyor (C / V2) includes a sensor S4 for detecting the printed circuit board P carried into the inlet of the reflow device 2, a sensor S5 for outputting a deceleration signal when the printed circuit board P is detected, A sensor S6 for detecting the stop position is provided.

  The transport chain device (C / V3) in the reflow device 2 includes a sensor S7 for detecting the carry-in of the printed board P and the support pins 36, a sensor S8 for confirming and detecting the passage of the printed board P, and the support pins 36. A sensor S9 for detecting the number and position of passages, a sensor S10 for confirming and detecting that the reflow soldered printed circuit board P has been carried out of the reflow apparatus 2, and a sensor for outputting a pin initial setting signal upon detection of the support pin 36 S11 and a sensor S12 that outputs a synchronization signal to the support pin lifting mechanism 52 upon detection of the support pin 36 are provided.

  As shown in FIG. 2, the buffer conveyor (C / V2) includes an endless fixed-side transport chain 8a and an endless movable-side transport chain 9a. The fixed-side transport chain 8a is connected to the drive-side sprocket 10a. The drive side sprocket 10a is fixed to a shaft 14 and is driven to rotate by a conveyor conveying motor 13. The driven sprocket 10b is rotatably attached to a ball screw 12. The ball screw 12 is rotated by a conveyor width changing motor 11 that is operated by a pulse signal.

  The movable-side transport chain 9a is hung on the driving-side sprocket 10a-1 and the driven-side sprocket 10b-1, and the driving-side sprocket 10a-1 is rotated by the rotation of the shaft 14, but moves in the axial direction of the shaft 14. The driven sprocket 10 b-1 is screwed into the ball screw 12.

  Accordingly, the rotation of the conveyor transport motor 13 causes the fixed-side transport chain 8a and the movable-side transport chain 9a to rotate via the drive-side sprockets 10a and 10a-1, and the rotation of the conveyor width changing motor 11 causes the rotation. The driven sprocket 10b-1 is moved via the ball screw 12 to move the movable conveying chain 9a, the width is automatically changed, and the conveying speed can be varied.

  The transport chain device (C / V3) in the reflow device 2 includes a fixed-side transport chain base (not shown) and a direction perpendicular to the transport direction (width direction) with respect to the fixed-side transport chain base (width direction). And a movable-side transport chain base (not shown) that can move to the fixed-side transport chain base, as shown in FIG. Motor 16 and a drive-side shaft 17 that is rotationally driven by the conveyor conveying motor 16 are installed. A drive-side fixed sprocket 15a is fixed to the drive-side shaft 17, and the drive side The shaft 17 is provided with a drive-side movable sprocket 15 a-1 that rotates in the axial direction of the drive-side shaft 17 while rotating by the rotation of the drive-side shaft 17.

  Further, a driven side shaft 18 is disposed on the fixed side transport chain base so as to be positioned on the inlet side of the reflow device 2, and a driven side fixed sprocket 15b is fixed to the driven side shaft 18, and The driven side shaft 18 is provided with a driven side movable sprocket 15b-1 that moves in the axial direction of the driven side shaft 18. The movable-side transport chain base holds the drive-side movable sprocket 15a-1 and the driven-side movable sprocket 15b-1 in a rotatable manner.

  An endless fixed-side transport chain 8b is hung on the driving-side fixed sprocket 15a and the driven-side fixed sprocket 15b, and an endless driven-side on the driving-side movable sprocket 15a-1 and the driven-side movable sprocket 15b-1. A conveying chain 9b is hung. The fixed-side transport chain 8b and the driven-side transport chain 8b are provided with a large number of connecting pins 10 inside thereof.

  The transport chain device (C / V3) is provided with a transport chain width changing mechanism 19 which is a transport chain width changing means. The transport chain width changing mechanism unit 19 includes a drive mechanism unit 20 and driven mechanism units 21 </ b> A and 21 </ b> B disposed before and after the drive mechanism unit 20. The drive mechanism unit 20 is installed on the fixed-side conveyance chain base and moves by a call pulse signal, a width changing motor 22, a ball screw 23 that is rotationally driven by the width changing motor 22, and a screw shaft tip of the ball screw 23. The driven mechanism portion 21A includes a ball screw 25a rotatably installed on the fixed-side conveyance chain base, and a sprocket 26a fixed to the screw shaft tip of the ball screw 25a. The driven mechanism portion 21B has a ball screw 25b that is rotatably installed on the fixed-side transport chain base, and a sprocket 26b that is fixed to the tip of the screw shaft of the ball screw 25b.

  An endless chain 27 is hung on the sprocket 24, the sprocket 26a, and the sprocket 26b, and the nut portions 23-1, 23a-1, and 23b-1 of the ball screws 23, 23a, and 23b are respectively conveyed on the movable side. It is attached to the chain base.

  Accordingly, the ball screw 23 is rotated by rotationally driving the width changing motor 22 of the drive mechanism unit 20, and the sprockets 26a and 26b are rotated via the chain 27 by rotating the sprocket 24 at the tip of the ball screw 23. The ball screws 23a and 23b are rotated to move the movable conveyance chain base, and the movable conveyance chain 9b is moved in the width direction to change the width between the fixed and movable conveyance chains 8b and 9b.

  Further, the transport chain device (C / V3) includes a warp prevention chain base (not shown) that can move in a direction (width direction) perpendicular to the transport direction a with respect to the fixed side transport chain base, and a warp. Prevention mechanism portion 50, warp prevention chain movement adjustment mechanism portion 51 which is a warp prevention chain movement adjustment means, and a support pin which raises support pin 36 provided in warpage prevention chain 30 to an arbitrary pitch at three levels. A lifting mechanism 52 and a support pin initial setting mechanism 53 for initial setting of the raised support pin 36 are provided.

  As shown in FIG. 2, the warpage prevention mechanism 50 includes a drive sprocket 28, a driven sprocket 29, and a warp prevention chain 30 hung on the drive sprocket 28 and the driven sprocket 29. The drive sprocket 28 is rotated by the rotation of the drive side shaft 17, but is provided on the drive side shaft 17 so as to move in the axial direction of the drive side shaft 17, and the driven sprocket 29 is provided with the driven side shaft 18. The driven shaft 18 is provided so as to move in the axial direction. The drive sprocket 28 and the driven sprocket 29 are held by a chain base for warpage prevention.

  As shown in FIG. 3, a large number of support pin holding mechanism portions 54 that hold the support pins 36 are provided at a predetermined pitch interval in the conveyance direction A on the side portion of the warp prevention chain 30. As shown in FIGS. 6 and 7, these support pin holding mechanism portions 54 have a holding bracket 31, and by replacing one part of the piece 30 </ b> A of the warp preventing chain 30 with the holding bracket 31, A large number of holding brackets 31 are provided every other piece 30A. The holding bracket 31 has a U-shaped cross section having two upper and lower plate portions 32, 33, and an opening 34 is provided at the center of the plate portions 32, 33. A pair of holding springs 35a and 35b are mounted on the.

  The support pin 36 has a pin main body 36A. The upper and lower ends of the pin main body 36A are spherical, and the pin main body 36A is provided with upper and lower and intermediate locking portions 37, 38, and 39. . These locking portions 37, 38, 39 have a spherical shape having a diameter larger than the diameter of the pin main body 36A.

  As shown in FIG. 7, the support pin 36 penetrates through the opening portions 34 of the plate portions 32 and 33 of the bracket 31, and a pair of holding springs 35 a and upper portions on the intermediate locking portion 38. It is hold | maintained at the bracket 31 by being clamped by 35b. In this case, when the support pin 36 is moved up and down by an external force such as a cam, the holding springs 35a and 35b are bent and the locking portion 38 passes through the opening 34, and either of the upper and lower locking portions. 37 and 38 are positioned in the opening 34, and the upper and lower portions of the locking portion are held by the pair of holding springs 35a and 35b so as to be held by the bracket 31.

  As shown in FIG. 2, the warp preventing chain movement adjusting mechanism 51 includes a drive mechanism 40 and driven mechanism portions 41 </ b> A and 41 </ b> B arranged before and after the drive mechanism 40. The drive mechanism section 40 is installed on the fixed-side conveyance chain base and moves by a movement adjustment motor 42 that moves in response to a call pulse signal, a ball screw 43 that is rotationally driven by the movement adjustment motor 42, and a screw shaft tip of the ball screw 43. The driven mechanism 41A includes a ball screw 45a that is rotatably installed on the fixed-side conveyance chain base, and a sprocket 46a that is fixed to the screw shaft tip of the ball screw 45a. The driven mechanism portion 41B has a ball screw 45b that is rotatably installed on the fixed-side conveyance chain base, and a sprocket 46b that is fixed to the tip of the screw shaft of the ball screw 45b.

  An endless chain 47 is hung on the sprocket 44, the sprocket 46a, and the sprocket 46b, and the nuts 43-1, 43a-1, and 43b-1 of the ball screws 43, 43a, and 43b are respectively attached. .

  Accordingly, the ball screw 43 is rotated by rotationally driving the movement adjusting motor 47 of the drive mechanism unit 40, the sprocket 44 at the tip of the ball screw 43 is rotated, and the sprockets 46a and 46b are rotated via the chain 42. The ball screws 43a and 43b are rotated to move the warp prevention chain base, and the movement of the warp prevention chain 30 is adjusted.

  As shown in FIGS. 1 and 2, the support pin lifting / lowering mechanism 52 is located below the entrance of the transport chain device (C / V 3) and lifts the support pin 36 mounted on the warp prevention chain 30. It has a structure that pushes down from the bottom. That is, as shown in FIGS. 8 and 9, the support pin elevating mechanism 52 includes a cam holding member 55, and this cam holding member 55 is held by the apparatus main body 2 </ b> A via the ball slider 56. . Further, a nut portion (not shown) of a ball screw 57 is attached to the cam holding member 55, and a shaft portion 57A of the ball screw 57 is coupled to an output shaft 58A of a base moving motor 58 provided in the apparatus main body 2A. 59, the support pin lifting mechanism moving adjustment means is constituted by these.

  The cam holding member 55 holds three types of cams, ie, a stopper height cam 60a, a support height cam 60b, and a free height cam 60c in a rotatable state between the holding piece portions 55A. The rotating shaft 62 penetrates through the central portion of the holding piece portion 55A of the cam holding member 55, the stopper height cam 60a, the support height cam 60b, and the free height cam 60c. The cam 60a, the support height cam 60b, and the free height cam 60c are rotated by the rotation of the rotary shaft 62, and can be moved in the axial direction of the rotary shaft 62. The rotating shaft 62 is connected to an output shaft 63A of the support pin lifting / lowering motor 63 via a shaft coupling 64, and these constitute a rotation driving means.

  Since the speed at which the support pin raising motor 63 rotates once and the speed at which the support pin 36 fixed to the warp prevention chain 30 moves by one pitch are the same, the height of the three stages of the support pins 36 is increased. Can be changed one by one.

  Further, when the base moving motor 58 rotates, the cam holding member 55 screwed to the ball screw 57 moves in the width direction, and three types of stopper height cams 60a, support height cams 60b, and free height cams. By rotating 60 c at the position of the support pin 36, the support pin 36 can be raised. In order to synchronize the speed of the warp prevention chain 30 and the rotation speed of the stopper height cam 60a, the support height cam 60b, and the free height cam 60c, it is supported by the sensor S12 at a position one pitch before the lift. The pin 36 is detected.

  As shown in FIGS. 1 and 2, the support pin initial setting mechanism 53 is located in the lower part of the outlet of the transport chain device (C / V3). Then, as shown in FIG. 12, the support pin initial setting mechanism 53 is attached to the initial setting mechanism base 70 fixed in the reflow device 2 via the height adjustment bracket 71. Configured.

  The initial setting bracket 72 is processed to have three levels of height with an inclined upper surface. The upper level is the free height position (c) of the support pin 36, the middle level is the support height position (b), and the lower level. Is adjusted by the height adjustment bracket 71 so as to be the same relative position as the stopper height position (a). In FIG. 12, the movement direction of the warp prevention chain 30 is from right to left, and ascends one step at a time after passing through the slope of the initial setting bracket 72. At that time, in order to correct the upward slack of the warp prevention chain 30, the correction bracket 73 is slidable on the upper part of the warp prevention chain 30.

  Accordingly, the support pin 36 slides on the slope of the initial setting bracket 72 by the movement of the warp prevention chain 30, and the support pin 36 is moved to the free height position (c), the support height position (b), and the stopper height position. Initially set for each of (a). That is, as shown in FIG. 3 and FIG. 10, there are three types of height of the support pin 36, and the first is in contact with the end face Pa on the front side in the transport direction A of the printed board P, and the printed board P The stopper height position (a) prevents misalignment at the time of transport, and the second is a support height position (b) that contacts the back surface of the printed circuit board P to prevent warpage, and the third is a print height. This is a free height position (c) that secures a height H (about 10 to 20 mm) that does not interfere with the electronic component 80 mounted on the back surface of the substrate P. These three types of height are raised by rotation of the three types of stopper height cams 60a, support height cams 60b, and free height cams 60c.

  Therefore, when both side ends in the width direction of the printed circuit board P on which double-sided reflow soldering is performed are placed on the connecting pins 10 of the pair of left and right transport chains 8b and 9b, as shown in FIGS. The support pins 36 that can be raised and lowered in the prevention chain 30 come into contact with the back surface of the printed circuit board P so as to avoid the electronic components 80 mounted on the back surface of the printed circuit board P.

  Next, the coordinate which is one of the arrangement | positioning information of the support pin 36 is demonstrated using the coordinate explanatory drawing of FIG.

  The transport direction B of the printed circuit board P is from left to right in FIG. 11, and the support pins 36 interfere with each other because the printed circuit board P is placed on the connecting pins 10 of the transport chains 8b and 9b. There is an area where support pins cannot be placed.

  Next, a case where three support pins 36 are erected will be described as an example. The breakdown of the three support pins 36 includes one support pin 36 (stopper pin 36a) at the stopper height position (P0) (a) and one support pin 36 (support pin position (P1, P2) (b) ( There are two support pins 36b), and the X coordinate is a value common to the three support pins 36.

  Next, regarding the Y coordinate, the stopper height position (P0) (a) is {reference Y coordinate-2 (half of φ4)} when the diameter of the support pin 36 is φ4. On the other hand, the support height positions (P1, P2) and (b) are (2.54 × n) when the mounting pitch of the support pins 36 is 2.54 mm (n is an integer).

  In this case, as shown in FIG. 13, when the support pin mounting interval of the transport chain 30 is 2.54, the stopper pin 36a and the support pin 36b are raised by the support pin lifting mechanism 52 at the same time as the start, The interval S between the stopper pins 36a rises so that S> Lp + 4 and S = 2.54 × n. Usually, the printed circuit board insertion interval needs to be maintained at least the printed circuit board length Lp in order to stabilize the uniform heat transfer in the apparatus main body 2A or when filling with nitrogen, and the stopper pin 36a is detected by the sensor S9. As a result, the control program is such that a space larger than the printed board length Lp + 4 is secured at the same time by providing at least one gap S between the stopper pins 36a, and the printed board P is put into the reflow apparatus 2.

  Next, a method for transporting the printed circuit board P of the buffer conveyor (C / V2) and the transport chain device (C / V3) will be described with reference to the transfer section shown in FIG. 14 and the flowchart of FIG.

  The control unit includes arrangement information of the support pins 36 (36a, 36b, 36c) {the size of the printed circuit board P, the speed of the buffer conveyor (C / V2), the position of the support pins 36 (36a, 36b, 36c), etc.}}. It has been entered. In step T1, the control unit operates the support pin lifting / lowering mechanism 52 based on the arrangement information of the support pins 36, and the transport chains 8b and 9b of the buffer conveyor (C / V2) and the transport chain device (C / V3). Start.

  Next, in step T <b> 2, the sensor S <b> 4 detects whether or not the printed board P is carried into the inlet portion of the reflow device 2. In step T3, it is determined whether or not the printed circuit board P is present on the buffer conveyor (C / V2). If it is determined that the printed circuit board P is present, the sensor S2 passes the printed circuit board P in step T4. Detects and decelerates the buffer conveyor (C / V1), and sensor S3 detects the printed circuit board P and instructs the control unit to stop the buffer conveyor (C / V2). This buffer conveyor (C / V2) To stop.

  Next, if it is determined in step T3 that there is no printed circuit board P, the printed circuit board P is loaded into the buffer conveyor (C / V2) in step T5, and the sensor S4 carries in the printed circuit board P in step T6. The sensor S5 detects the passage of the printed circuit board P and decelerates the buffer conveyor (C / V2). Further, the sensor S6 detects the front end surface Pa of the printed circuit board P and sends the buffer conveyor (C / V2) is commanded to stop, and this buffer conveyor (C / V2) is stopped.

  On the other hand, the transport chains 8b and 9b of the transport chain device (C / V3) are continuously operated at a constant speed, and the support pins 36 are raised to a desired interval and height by the support pin lifting mechanism 52.

  Next, in step T7, the stopper height detection sensor S9 detects the stopper pin 36a, and it is determined whether or not the stopper pin 36a is detected twice or more in the control unit. If it is not detected more than once, the stopper pin 36a is detected again by the stopper height detection sensor S9.

  Next, when it is determined in step T7 that the stopper pin 36a has been detected twice or more, a conveyor start signal is sent to the buffer conveyor (C / V2) in step T8. Therefore, the buffer conveyor (C / V2) rotates and feeds the printed circuit board P onto the transport chains 8b and 9b of the transport chain device (C / V3). At this time, the speeds of the transport chains 8b and 9b of the buffer conveyor (C / V2) and the transport chain device (C / V3) are the same, and the positional relationship is (r = L + 5 mm) (see FIG. 14).

  Next, in step T9, the sensor S7 detects that the stopper pin 36a has passed, and the control unit increases the speed of the buffer conveyor (C / V2) (1 of the transport chain device (C / V3)). The tip surface Pa of the printed circuit board P is slightly abutted against the stopper pin 36a. Next, in step T10, the support pins 36b are sequentially brought into contact with the back surface of the printed circuit board P, and are conveyed through the reflow apparatus 2 with the printed circuit board P supported from the back.

  Next, in step T10, when the sensor 10 confirms that the reflow soldered printed circuit board P has been unloaded from the reflow apparatus 2, for example, a support pin initial setting button (not shown) is pressed to set the support pin initial setting. The mechanism 53 is actuated to initially set the support pins 36 (stopper pins 36a and support pins 36b). When the transport chains 8b and 9b of the transport chain device (C / V3) make one round, a buzzer (not shown) is sounded. To finish.

  As described above, according to the first embodiment of the present invention, when the printed circuit board P is transported in the reflow apparatus 2, so as not to interfere with the electronic component 80 already mounted on the back surface of the printed circuit board P. The support pins 36 (stopper pins 36a and support pins 36b) can be arranged at arbitrary position coordinates, and the support pins 36 (support pins 36b) can be brought into point contact with the back surface of the printed circuit board P so that the contact area becomes as small as possible. Thus, warping of the printed circuit board P can be easily and reliably prevented.

  Further, the warp prevention chain 30 and the support pins 36 (support pins 36b) themselves are as compact and small in heat capacity as possible without impeding the heat transfer from the heater to the printed circuit board P. Can be uniformly applied to the printed circuit board P, and is also effective when using lead-free solder having a high melting point.

  Further, according to the first embodiment of the present invention, a pair of the upper and lower portions of the intermediate locking portion 39 is paired with the support pin 36 penetrating through the opening portions 34 of the plate portions 32 and 33 of the holding bracket 31. The holding pin 36 is held by the holding bracket 31 by being held between the holding springs 35a and 35b, and the external force of the stopper height cam 60a, the support height cam 60b and the free height cam 60c When it is raised and lowered, the holding springs 35a and 35b are bent, the locking portion 39 passes through the opening 34, and the upper and lower locking portions 37 and 38 are positioned in the opening 34. The upper part and the lower part of the engaging part are held between the pair of holding springs 35a and 35b, so that the holding bracket 31 holds the printed part P. When the printed circuit board P is transported in the reflow apparatus 2, the printing is already performed. Substrate P Without interfering with the electronic component 80 mounted on the back surface, the support pins 36 can be point contact.

  In addition, according to the first embodiment of the present invention, the stopper height cam 60a is obtained by rotating the stopper height cam 60a, the support height cam 60b, and the free height cam 60c by the rotation driving means. The support pin (stopper pin 36a) is set to a stopper height position that contacts the front end surface Pa of the printed circuit board P to prevent displacement when the printed circuit board P is conveyed, and a support height cam 60b is provided. The support pin (support pin 36b) is set to a support height position that contacts the back surface of the printed circuit board P to prevent warping, and a free height cam 60c mounts the support pin 36 on the back surface of the printed circuit board P. It is possible to set the height at a free height that does not interfere with the electronic component 80 being secured.

  Further, according to the first embodiment of the present invention, the support pin 36 slides on the slope of the initial setting bracket 72 by the movement of the warp preventing chain 30, and the support pin 36 is moved to the free height position and the support height position. In order to initially set each of the stopper height positions, the support pin 36 can be brought into contact with the back surface of the printed circuit board P so as to avoid the electronic component 80 mounted on the back surface of the printed circuit board P.

  In addition, according to the first embodiment of the present invention, the width of the pair of transport chains 8b and 9b is changed by the transport chain width changing mechanism unit 19, thereby enabling the transport of the printed circuit board P having different width dimensions. The movement of the warp prevention chain 30 is adjusted by the warp prevention chain movement adjusting mechanism 51, and the movement of the support pin lifting mechanism 52 is adjusted by the support pin lifting mechanism moving adjustment means. It is possible to easily set the arrangement of the support pins 36 according to the component mounting 80, the board shape, etc., and to facilitate the reflow soldering of a wide variety of printed circuit boards P that perform the double-sided reflow soldering. .

  Further, according to the embodiment of the printed circuit board warpage preventing method in the reflow apparatus according to the present invention, the plurality of support pins 36 provided in the warp prevention chain 30 are arranged at a plurality of stages at arbitrary pitches by the support pin lifting mechanism 52. By raising and lowering the height and supporting the printed circuit board P from the back side by the support pins 36, it is possible to prevent the printed circuit board P from warping during the transport process of the reflow device 2.

  Further, according to the embodiment of the printed circuit board warpage preventing method in the reflow apparatus according to the present invention, the support pin 36 can be automatically brought into contact with the back surface of the printed circuit board P at an arbitrary coordinate, and is a transport upstream conveyor. By controlling the speed of the buffer conveyor (C / V2) and the conveyance timing, the printed circuit board can be automatically loaded into the reflow apparatus. For this reason, it is possible to automatically produce reflow soldering of a wide variety of printed circuit boards P that perform reflow soldering, and to support double-sided reflow soldering with high-density mounting printed circuit boards and lead-free solder, which are increasing in the future. become.

(Embodiment 2)
A second embodiment of the present invention is shown in FIGS.

  In the second embodiment of the present invention, the warp prevention chain 30 is constituted by a roller chain, and the chain side hinge portion 70 is formed on the piece 30A of the warp prevention chain 30. In addition, two types of support pins 36-1 and 36-2 having different pin lengths are used as the support pins, and these support pins 36-1 and 36-2 are attached to the pin-side hinge portion 71. .

  And the pin side hinge part 71 is attached to the chain side hinge part 70 so that inclination is possible by the hinge pin 72, and the support pin 36-1 and the support pin 36-2 are arrange | positioned alternately. The chain side hinge part 70, the pin side hinge part 71, and the hinge pin 72 constitute a hinge mechanism part.

  Then, as shown in FIG. 18 (1), the state in which the long support pin 36-1 is tilted upward is the stopper height position (a), as shown in FIG. 18 (2). The state where the short support pin 36-2 is tilted so as to face upward is the support height position (b). And as shown in FIG. 16, the state which does not tilt the support pin 36-1 and the support pin 36-2 becomes a free height position (c).

  The difference from Embodiment 1 of the present invention described above is that the two types of support pins 36-1 and support pins 36-2 are alternately arranged, and the support pins 36-1 and the support pins 36-2 are arranged alternately. If the program is changed to double the mounting interval with 36-2, the effect of warpage prevention functions as in the first embodiment.

  According to the above-described second embodiment of the present invention, two types of support pins 36-1 and 36-2 having different pin lengths are arranged on the warp prevention chain 30 so as to be tiltable and alternately by a hinge mechanism. By attaching, the state where the long support pin 36-1 is tilted so as to face upward is the stopper height position (a), and the state where the short support pin 36-2 is tilted so as to be upward is the support height. The support pin 36-2 is printed so that the contact area becomes as small as possible when the position (b) is reached and the support pins 36-1 and 36-2 are not tilted is the free height position (c). It is possible to make point contact with the back surface of the substrate P, and it is possible to easily and reliably prevent the printed substrate P from warping.

  The present invention provides a support pin at an arbitrary position coordinate so as not to interfere with an electronic component already mounted on the back surface of the printed circuit board when transporting the printed circuit board in the reflow apparatus, and to make the contact area as small as possible. Can be brought into contact with the back surface of the printed circuit board with a point, and the printed circuit board can be easily and reliably prevented from warping, for example, on a printed circuit board on which paste-like solder is printed in advance. After mounting surface-mounted electronic components on the pad portion of the substrate, the printed circuit board is transported, and paste-form solder is heated, melted and solidified, and soldering is performed. It is effective for automatic transfer of workpieces in high-temperature equipment, and has a compact structure that is relatively easy to insulate heat. It is useful in the field to request the heat transfer.

BRIEF DESCRIPTION OF THE DRAWINGS It is schematic structure explanatory drawing of the reflow apparatus provided with the curvature prevention apparatus (Embodiment 1) of the printed circuit board which concerns on this invention. It is a schematic plan view of the reflow apparatus. It is a top view of the double-sided reflow soldering printed circuit board of the conveyance state in the reflow apparatus. It is an arrow view from the A direction of FIG. It is an arrow view from the B direction of FIG. It is a top view of a support pin holding mechanism part. It is a front view of the support pin holding mechanism part. It is a side view of a support pin raising / lowering mechanism part. It is a top view of the support pin raising / lowering mechanism part. It is a front view of the support pin raising / lowering mechanism part. It is explanatory drawing of the arrangement | positioning coordinate of a support pin. It is explanatory drawing of a support pin initial setting mechanism part. It is space | interval explanatory drawing of a support pin. It is explanatory drawing of a transfer part. It is a flowchart showing the conveyance operation | movement order of a printed circuit board. It is a schematic front view of the chain for warp prevention in the reflow apparatus provided with the warp prevention apparatus (Embodiment 2) of the printed circuit board which concerns on this invention. It is a schematic side view of the chain for warpage prevention. (1), (2) is operation | movement explanatory drawing of the support pin in the curvature prevention apparatus (Embodiment 2) of the printed circuit board concerning this invention. It is schematic structure explanatory drawing of the reflow apparatus provided with the curvature prevention apparatus of the conventional printed circuit board. It is a schematic sectional drawing of the reflow apparatus. It is explanatory drawing showing the curvature state of the printed circuit board. It is explanatory drawing of the curvature prevention apparatus of the conventional printed circuit board. It is explanatory drawing of the other conventional curvature prevention apparatus of a printed circuit board.

Explanation of symbols

P Printed circuit board (C / V1) Buffer conveyor (C / V2) Buffer conveyor (C / V3) Transport chain device 1 Mounting machine 2 Reflow device 3 Printed circuit board storage device 8b Transport chain 9b Transport chain 10 Connection pin 19 Change of transport chain width Mechanism (conveying chain width changing means)
30 Warp prevention chain 36 Support pin 36a Stopper pin 36b Support pin 36c Free height position support pin 51 Warpage prevention chain movement adjustment mechanism (warp prevention chain movement adjustment means)
52 Support Pin Elevating Mechanism 53 Support Pin Initial Setting Mechanism 55 Cam Holding Member 60a Stopper Height Cam 60b Support Height Cam 60c Free Height Cam 80 Electronic Components

Claims (8)

A printed circuit board on which electronic components are mounted is placed on a transport chain at both end portions in the width direction, and the printed circuit board in a reflow apparatus is heated and soldered while transporting the printed circuit board by rotating the transport chain. A warpage prevention device,
Between the transport chains, a warp prevention chain that is arranged in parallel to the transport chains and rotates in the transport direction of the printed circuit board;
A large number of support pins provided on the warp prevention chain so as to be movable up and down and supporting the printed circuit board from the back;
A support pin raising / lowering mechanism for raising and lowering the support pin at an arbitrary pitch to a height of a plurality of stages;
An apparatus for preventing warping of a printed circuit board in a reflow apparatus, comprising: a support pin initial setting mechanism unit that sets the support pin raised and lowered by the support pin lifting mechanism to an initial position. A large number of holding brackets are provided on the side of the chain for preventing warpage at predetermined intervals in the conveying direction, and these holding brackets have two upper and lower plate parts, Each has an opening, and a pair of holding springs are mounted inside these openings,
The support pin has a plurality of spherical locking portions at predetermined intervals in the axial direction thereof,
The said support pin is hold | maintained at the holding | maintenance bracket by clamping the upper part and the lower part of any one of the said latching | locking parts with the said holding spring in the state which penetrated the said opening part. 2. A warp prevention device for a printed circuit board in the reflow apparatus according to 1. The support pin lifting mechanism rotates the stopper height cam, the support height cam, the free height cam, and the stopper height cam, the support height cam, and the free height cam. Rotational drive means for causing
By rotating the stopper height cam, the support height cam and the free height cam by the rotation driving means, the stopper height cam causes one of the support pins to be attached to the printed circuit board. The free height is set to a stopper height position that comes into contact with the front end surface, and the support height cam is set to a support height position where the other support pin abuts against the back surface of the printed circuit board. The cam for the other one of the support pins is set to a free height position that secures a height that does not interfere with an electronic component mounted on the back surface of the printed circuit board. An apparatus for preventing warping of a printed circuit board in the reflow apparatus according to claim 1. The support pin initial setting mechanism portion has an initial setting bracket whose upper surface is processed to three levels of upper, middle, and lower levels. The initial setting bracket has an upper level at a free height position, an intermediate level. Is adjusted by the height adjustment mechanism so that the lower position is at the same relative position as the stopper height position, and the support pin moves the slope of the initial setting bracket by the movement of the warp prevention chain. 4. The printed circuit board in the reflow apparatus according to claim 3, wherein the support pin is slid to be initially set to each of the free height position, the support height position, and the stopper height position. apparatus. The width of the pair of transport chains is changed by a transport chain width changing means, and the warpage prevention chain is adjusted by a movement prevention means for preventing warpage in a direction perpendicular to the transport direction of the printed circuit board. 5. The support pin lifting / lowering mechanism section is adjusted by a support pin lifting / lowering mechanism section movement adjusting means in a direction perpendicular to the transport direction of the printed circuit board. The warping prevention device for a printed circuit board in the reflow device according to any one of the above. A printed circuit board on which electronic components are mounted is placed on a transport chain at both end portions in the width direction, and the printed circuit board in a reflow apparatus is heated and soldered while transporting the printed circuit board by rotating the transport chain. A warpage prevention device,
Between the transport chains, there is a warp prevention chain that is arranged in parallel to these transport chains and rotates in the transport direction of the printed circuit board,
A print in a reflow apparatus, wherein two types of support pins having different pin lengths are attached to the warp prevention chain so as to be tiltable by a hinge mechanism and alternately arranged in the transport direction of the printed board. Board warpage prevention device. A method for preventing warping of a printed circuit board in a reflow apparatus that heats and solders a printed circuit board carrying electronic components,
The printed circuit board is conveyed by rotating the conveyance chain, and the warp prevention chain is rotated in synchronization with the rotation of the conveyance chain, and a plurality of support pins provided in the warp prevention chain are arranged at an arbitrary pitch. A printed circuit board in a reflow apparatus, wherein the printed circuit board is lifted up and down to a step height and supported by the support pins from the back side to prevent warping of the printed circuit board in a transport process of the reflow apparatus. Warpage prevention method. Considering the placement restrictions of the support pins due to component mounting on the back side of the printed circuit board, board shape, etc., the support pins are raised and lowered based on the pin arrangement information input in advance, and the speed of the conveying upstream conveyor 8. The method for preventing warping of a printed circuit board in a reflow apparatus according to claim 7, wherein the timing of unloading the printed circuit board is controlled and the printed circuit board is automatically loaded into the reflow apparatus.

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