JP2010147314A - Soldering device for shielding atmosphere - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soldering device for shielding the atmosphere capable of saving energy by reducing energy loss with a chamber body as a heat radiator. <P>SOLUTION: The soldering device 10 for shielding the atmosphere brings jet stream wave of molten solder into contact with a workpiece W to be soldered in a chamber 11 shielding the atmosphere, to solder. In the chamber 11, a skirt 11b acting as an opening 14 of the chamber 11 is soaked in the molten solder 16 in a solder tub 15 housing the molten solder, and the chamber is so formed in a body as to be divided into a plurality of pieces, and a seal members 17 and 18 having heat insulating property are interposed at the divided points. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus for performing flow soldering of a workpiece to be soldered, such as a printed wiring board, in a chamber body in which an atmosphere is shielded.

  In an inert gas atmosphere with a low oxygen concentration, oxidation of soldered portions such as lead terminals of electronic components and soldering lands of printed wiring boards is suppressed, and excellent solder wettability is obtained. Accordingly, since a small amount of flux may be applied in advance to the soldered portion, almost no flux residue remains on the printed wiring board after soldering.

For example, Patent Document 1 discloses a soldering apparatus in which a printed wiring board transfer conveyor is provided in a tunnel-shaped chamber, and a preheater and a solder bath that forms a jet wave of molten solder are provided in the transfer order. .
The tunnel-shaped chamber body has an area for conveying the printed wiring board at an elevation angle and an area for conveying the depression angle, and is formed in a “h” shape when viewed in a longitudinal section with respect to the conveyance direction of the conveyor. The elevation transport area is provided with a pre-heater and a solder bath that forms a jet wave of molten solder. In the depression transport area, the printed wiring board that is the work to be soldered is cooled.

  Further, the chamber body is provided with an opening facing the solder bath in order to position a jet wave of molten solder in the chamber body, and a skirt extending toward the solder bath is provided in this opening. The skirt is immersed in the molten solder in the solder bath, so that the opening is reliably sealed.

  A nozzle for supplying an inert gas such as nitrogen gas is provided on the rear side of the solder bath as viewed from the direction of conveyance of the printed wiring board. The directivity of nitrogen supply is determined so that the nozzle supplies nitrogen gas toward a region where the printed wiring board and the jet wave are in contact with each other. Thereby, an inert gas atmosphere having a low oxygen concentration is formed in the chamber. The suppression plate provided in the chamber body is a member that suppresses unnecessary atmospheric flow in the chamber body, and thereby constitutes a labyrinth seal.

  On the other hand, the solder tank is provided with a heater (not shown), a temperature sensor for detecting the temperature of the solder in the solder tank, and a temperature control device for controlling the power supplied to the heater. The temperature sensor and the temperature control device are configured to maintain the temperature of the molten solder in the solder bath at a predetermined temperature. Incidentally, the temperature of the molten solder is usually used at about 250 to 260 ° C.

  The preheater is provided with a means for performing hot wire heating, such as an infrared heater, a means for performing hot air heating, a means for using both hot wire heating and hot air heating, a sensor, and a temperature control device. The sensor and the temperature control device are configured such that the surface temperature and hot air temperature of the infrared heater become a predetermined temperature. Incidentally, it is used so that the temperature of the printed wiring board heated by the preheater is usually about 90 to 150 ° C.

  Next, soldering of the printed wiring board is performed as follows. That is, a printed wiring board on which flux has been applied in advance is carried in from the carry-in port of the chamber body. Then, the printed wiring board is heated by the preheater, and the pre-applied flux is dried and pre-activated. This heating is called preheating, and also has a role to alleviate heat shock when the printed wiring board comes into contact with the jet wave of the molten solder. When the preheating of the printed wiring board is completed, the printed wiring board is then brought into contact with the jet wave on the solder tank, and the molten solder is supplied to the soldered portion to be soldered. Thereafter, the printed wiring board is cooled and unloaded from the outlet of the chamber body to complete a series of flow soldering.

JP 2001-230538 A

  In the soldering apparatus as disclosed in Patent Document 1, a metal (particularly stainless steel) member is used for the chamber body. Therefore, thermal energy is conducted from the molten solder or preheater to the chamber body, and a large amount of thermal energy is released from the chamber body to the atmosphere.

  In particular, since the skirt of the chamber body is immersed in contact with molten solder of about 250 to 260 ° C., a large amount of heat energy is transferred from the skirt to the chamber body, and as a result, the chamber body having a very large surface area enters the atmosphere. Released and lost. Further, heat energy is also conducted from the preheater to the chamber body through hot wire heating or hot air heating, and is released from the chamber body into the atmosphere as before, resulting in loss.

  When analyzed by temperature, the preheater that heats the printed wiring board to about 90 to 150 ° C., that is, the preheating portion, the portion of the solder bath having molten solder of about 250 to 260 ° C., and the atmosphere in which the printed wiring board is cooled The three parts with the temperature (25 ° C.) part are connected to one. If the analysis is performed on the part where the printed wiring board is heated and the part where it is cooled, the two parts are connected to one.

  Also, lead-free solder has been used, most of which is lead-free solder mainly composed of tin. Therefore, the member in contact with the molten solder or the like in the solder tank, that is, the iron (stainless steel) member has a problem that erosion occurs or a hole is severely opened.

  The present invention has been made in view of the above-described problems, and is a soldering apparatus that performs soldering in a chamber body in which an atmosphere is shielded, and reduces energy loss using the chamber body as a radiator. The purpose is to save energy and to solder a printed wiring board with low power consumption and thus low carbon dioxide generation. Another object is to improve maintainability against erosion, for example.

An atmosphere shielding soldering apparatus according to the present invention is an atmosphere shielding soldering apparatus configured to perform soldering by bringing a jet wave of molten solder into contact with a work to be soldered in a chamber body in which the atmosphere is shielded. The body is integrally formed so that the skirt body as the opening of the chamber body is immersed in the molten solder accommodated in the solder bath, and can be divided into a plurality of parts. The sealing member which has is characterized by being interposed.
In particular, it is preferable to integrally form the chamber body while thermally dividing it according to the temperature distribution in a series of soldering steps. That is, in a soldering apparatus in which the skirt body as the opening of the chamber body is immersed in the molten solder accommodated in the solder bath, the molten solder in the solder bath constitutes the highest temperature portion, and the others Lower temperature. Therefore, the most heat energy is wasted to the chamber body via the skirt body, resulting in energy loss. Therefore, the chamber body is integrally formed so that it can be divided, and a heat insulating seal member is interposed at the divided portion, so that the loss of heat energy can be cut off and loss can be reduced. become able to.

In the atmosphere shielding soldering apparatus of the present invention, the chamber body is integrally formed so that the skirt body and the chamber body can be divided.
That is, conduction of heat energy from the skirt body to the chamber body is cut off, and heat energy released from the solder tank to the atmosphere and lost can be cut off, so that power consumption can be greatly reduced. It becomes like this. Further, even if the skirt body is immersed in the molten solder in the solder bath and erosion due to lead-free solder occurs, it can be easily replaced and the maintainability is improved.

Moreover, the atmosphere shielding soldering apparatus of the present invention is characterized by having an elevating device for changing the height position of the solder tank.
That is, by lowering the height position of the solder tank by the lifting device, the skirt body is released from the immersion of the molten solder in the solder tank, and can be easily removed from the chamber body and attached. Become.

In the atmosphere shielding soldering apparatus of the present invention, an electrical insulating layer having erosion resistance against molten solder is formed on the surface of the skirt body.
That is, in a printed wiring board on which a semiconductor electronic component that handles a weak signal is mounted, characteristics deteriorate even with a slight leakage current of about several tens of nA (nanoampere) or a slight leakage voltage of about several tens of mV (millivolt). Subject to irreversible stress. Therefore, it is necessary to be insulated from a solder bath that handles a large power of several kW (kilowatts) at several hundred volts (volts).
By forming an electrically insulating layer having erosion resistance against molten solder on the skirt body, it is possible to insulate from the solder bath, and the insulating layer is also eroded and does not cause dielectric breakdown.

In the atmosphere shielding soldering apparatus of the present invention, the chamber body can be divided into a first chamber body located in the heating area of the work to be soldered and a second chamber body located in the cooling area. The transport conveyor disposed in the chamber body is divided into a first transport conveyor located in the heating area and a second transport conveyor located in the cooling area. It is characterized by being.
That is, conduction of heat energy from the first chamber body located in the heating area to the second chamber body located in the cooling area is cut off, and heat energy released from the solder bath to the atmosphere is cut off. As a result, power consumption can be greatly reduced. Further, by dividing the transport conveyor in accordance with the division of the chamber body into the heating region and the cooling region, it becomes possible to eliminate the transfer of thermal energy from the heating region to the cooling region.

According to the present invention, the energy loss that makes the chamber body a heat radiator becomes extremely small, and the printed wiring board can be soldered with low power consumption. In other words, it is possible to stably perform soldering mounting with low power consumption and thus a small amount of generated carbon dioxide and excellent wettability.
For example, even if the skirt body is eroded by lead-free solder, the skirt body can be easily replaced.

Hereinafter, preferred embodiments of an atmosphere shielding soldering apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a view for explaining an atmosphere shielding soldering apparatus according to the present invention, and is a view showing a longitudinal section in a transport direction of a transport conveyor. FIG. 2 is a perspective view for explaining the skirt body. In the present embodiment, as a part to be soldered to be soldered, for example, a printed wiring board (hereinafter referred to as a work W) on which electronic parts are mounted will be described.

  First, as shown in FIG. 1, as a main configuration of the atmosphere shielding soldering apparatus 10, a tunnel-shaped chamber body 11 for shielding an atmosphere, and a conveyor 12 for conveying a workpiece W in the direction of an arrow in the chamber body 11. And a jet wave forming device 13 for forming jet waves.

  The chamber body 11 is configured to include a chamber body 11a having a letter “H” shape when viewed in a longitudinal section with respect to the transport direction of the transport conveyor 12, and a skirt body 11b connected to the chamber body 11a. The skirt body 11b is connected in such a manner that the opening of the opening 14 formed in the chamber main body 11a at the position where the jet flow forming device 13 is disposed extends along the downward direction. The lower side of the skirt body 11b is immersed in the molten solder 16 accommodated in the solder bath 15 of the jet wave forming device 13. The chamber body 11a and the skirt body 11b are integrally formed so as to be divided. For example, a silicone rubber-based heat-insulating seal member 17 is interposed at a portion where the chamber body 11a and the skirt body 11b are divided. The configuration and connection of the skirt body 11b will be described later with reference to FIG.

  Next, the chamber body 11a has a heating region for conveying the workpiece W at an elevation angle (θ1) and a cooling region for conveying the depression W (θ2). The chamber body 11a is configured by connecting a first chamber body 11a1 located in the heating area and a second chamber body 11a2 located in the cooling area. The first chamber body 11a1 and the second chamber body 11a2 are integrally formed so as to be divided. For example, a silicone rubber-based heat-insulating seal member 18 is interposed at a portion where the first chamber body 11a1 and the second chamber body 11a2 are divided. Here, the seal member 18 has a role of hermetically sealing and thermally insulating a portion where the first chamber body 11a1 and the second chamber body 11a2 are divided.

  In the first chamber body 11 a 1, a first transport conveyor 12 a that transports the workpiece W is disposed from the carry-in port 19 to the top 20. Similarly, in the second chamber main body 11a2, a second transfer conveyor 12b is disposed from the top portion 20 to the carry-out port 21. Further, a plurality of restraining plates 23 are arranged in parallel in the first chamber body 11a1 and the second chamber body 11a2, and a labyrinth seal structure is formed in the tunnel-shaped chamber body 11a.

  A preheater 25 for preheating the workpiece W is disposed in the first chamber body 11a1 and upstream of the jet wave forming device 13 in the workpiece W conveyance direction. As the preheater 25, for example, an electric heater or the like ensuring electrical insulation is used. Further, the preheater 25 is provided in the first chamber main body 11a1 with a heat-resistant insulator such as an insulator as a preheater unit, and has a preheater 25 of about several tens of volts and the first chamber main body 11a1. Ensures electrical insulation. The preheater 25 performs heat ray heating using infrared rays. And it is the structure which controls the electric power supplied to the said heater so that a heater surface temperature may be detected with a sensor and it may maintain at the predetermined temperature predetermined by the temperature control apparatus. The preheater 25 may be in the form of hot air heating or combined heating of hot wire heating and hot air heating. In the region where the preheater 25 is disposed, the workpiece W is preheated to about 90 to 150 ° C.

  A nozzle 26 for supplying an inert gas such as nitrogen gas is provided in the first chamber body 11a1 and on the rear stage side of the jet wave forming device 13 in the conveying direction of the workpiece W. The nozzle 26 has directivity of nitrogen gas supply so that the nitrogen gas is supplied toward a region where the workpiece W conveyed by the first conveyor 12a contacts the jet wave. Thereby, an inert gas atmosphere having a low oxygen concentration is formed in the chamber body 11. The lower side of the skirt body 11b that extends the opening of the opening portion 14 of the first chamber body 11a1 in the downward direction is immersed in the molten solder 16 of the solder bath 15, so that nitrogen gas is opened. It is not discharged from the section 14.

  A jet wave formed by the jet wave forming device 13 blows out from the opening 14 in the first chamber body 11a1 to the height of the first conveyor 12a. The jet wave forming device 13 contains molten solder 16 heated by a heater (not shown) provided in the solder bath 15. The jet wave forming device 13 feeds the molten solder 16 to the air outlet 29 of the air outlet body 28 by the pump 27, and forms a jet wave on the air outlet 29. The jet wave forming device 13 is provided with a sensor and a temperature control device (not shown) for detecting the temperature of the molten solder 16 in the solder bath 15. Then, the temperature of the molten solder is detected by a sensor, and the electric power supplied to the heater is controlled so as to maintain the temperature at a predetermined temperature by a temperature control device. The molten solder 16 in the solder bath 15 is heated to about 250 to 260 ° C. Therefore, a jet wave heated to about 250 to 260 ° C. is blown out to the opening 14 of the first chamber body 11a1.

Next, the configuration and connection method of the skirt body 11b described above will be described. The skirt body 11b is provided so as to be detachable from the opening 14 of the first chamber body 11a1 in such a manner as to surround the air outlet 29 of the jet wave forming device 13 and eventually the jet wave.
As shown in FIG. 2, the skirt body 11b is formed in the box shape opened up and down. Here, the upper opening serves as a joint opening 31 that joins the opening 14 of the chamber body 11a. The inclination of the opening surface of the joint opening 31 is formed at substantially the same angle as the inclination θ1 for conveying the workpiece W at an elevation angle. That is, the bonding opening 31 is formed so as to be lower toward the side attached to the carry-in port 19 side of the chamber main body 11a and to be higher toward the side attached to the top 20 side of the chamber main body 11a. Further, as described above, the heat-insulating seal member 17 made of a silicone rubber-based member is provided on the entire periphery of the joint opening 31 at a portion that joins the opening 14 of the chamber body 11a. Yes. Here, the seal member 17 has a role of hermetically sealing and thermally insulating a portion where the skirt body 11b and the first chamber body 11a1 are divided. On the other hand, the opening surface of the lower opening 37 is formed horizontally so that the whole is immersed in the molten solder 16 of the solder bath 15.

  Further, as shown in FIG. 2, a position restricting plate 32 protruding upward is provided at a part of the periphery of the joint opening 31 of the skirt body 11b. In addition, on the side surfaces of the skirt body 11b on both sides parallel to the conveying direction of the workpiece W (the arrow direction shown in FIG. 2), hooking fixtures 33 are provided as the locked portions. On the other hand, on the side surfaces of the first chamber body 11a1 on both sides parallel to the conveyance direction of the workpiece W, the locking tools 34 as locking members are provided at positions corresponding to the hooking fixtures 33, respectively. It has been. The locking tool 34 is provided with an operation portion 36. The operation unit 36 can be rotated from the state shown in the right side locking tool 34b shown in FIG. 2 to the state shown in the left side locking tool 34a. By rotating the operation part 36 as shown by the left side locking tool 34a, the hook part 35 provided on the operation part 36 moves upward.

  Next, when the skirt body 11b is connected to the first chamber body 11a1, first, the position regulating plate 32 of the skirt body 11b is positioned at a predetermined position on a side plate (not shown) of the first chamber body 11a1. Next, after setting all the locking tools 34 to the state shown by the locking tools 34b, the hooks 35 are respectively hooked on the hook fixing tools 33 of the skirt body 11b. Thereafter, by rotating the operation part 36, the hook part 35 moves upward, and the skirt body 11b is integrally connected to the first chamber body 11a1. When the skirt body 11b connected to the first chamber body 11a1 is removed, the operating portion 36 is rotated as shown by the locking tool 34b, and then the hooking portion 35 is moved from the hook fixing tool 33 of the skirt body 11b. Just remove it. Since the skirt body 11b can be attached and detached with such a one-touch operation, the skirt body 11b can be easily replaced and the maintainability is improved. Note that this one-touch structure or a structure similar thereto is also used at a division location between the first chamber body 11a1 and the second chamber body 11a2.

  Further, on the surface of the skirt body 11b, a ceramic layer, nitride layer or intermetallic compound layer (eg, iron-aluminum intermetallic compound) having electrical insulation and erosion resistance against molten solder. Etc. are formed. In order to ensure electrical insulation, the thickness is desirably 30 μm or more. As a result, the solder tank 15 that handles power of several kW at several hundred volts is separated from the chamber body 11a and the conveyor 12 and handles weak currents and voltages of several tens of nA (nanoamperes) and several tens of nV (nanovolts). The semiconductor electronic component can be reliably protected.

  That is, the same applies to the pre-heater 25, but in the case of a member that is directly immersed in the molten solder 16 of the solder bath 15, such as the skirt body 11b joined to the first chamber body 11a1, the chamber body 11a is connected. Ensuring electrical insulation of the conveyor 12 is a special issue. Thus, the electrical insulation is taken into account because the printed wiring board on which the semiconductor electronic component that is extremely vulnerable to electrical stress is directly touched.

  Next, returning to FIG. 1, the jet wave forming device 13 is provided with an elevator device 40 as a lifting device below the solder tank 15. The elevator apparatus 40 moves up and down the solder tank 15 and the blowing body 28 to change the vertical position. The elevator apparatus 40 may be, for example, a feed screw type driven by a motor, a pantograph type, or the like. Here, when the elevator apparatus 40 lowers the solder tank 15 to the lowest position, a gap is generated between the lower end of the skirt body 11b and the upper end of the blower opening 29. In this state, the skirt body 11b can be attached to and detached from the first chamber body 11a1.

  In the atmosphere shielding soldering apparatus 10 configured as described above, the chamber main body 11a and the skirt body 11b are insulated and electrically insulated from the molten solder 16 in the solder bath 15. Further, the chamber body 11a and the conveyor 12 are integrally formed by dividing and heat insulating according to the temperature distribution. Accordingly, the chamber body does not act as a huge heat radiating member, and the workpiece W being soldered can be protected from electrical stress.

  For example, in a soldering apparatus in which a conveyor conveys and circulates continuously from a heating area to a cooling area, the heating area is heated by receiving supply of heat energy, and then the heat energy is transferred to the surroundings in the cooling area. It will repeatedly discharge and decrease in temperature, and it will operate as a heat energy feeder to increase losses. However, as in this embodiment, the conveyance conveyor 12 is divided from the first conveyance conveyor 12a located in the heating area and the second conveyance conveyor 12b located in the cooling area, thereby reducing the heat energy loss. It becomes possible to make it extremely small.

  Moreover, the first chamber body 11a1 and the first transfer conveyor 12a, the second chamber body 11a2 and the second transfer are made at the top 20 (the highest position) of the chamber body 11a in which a high temperature atmosphere tends to accumulate due to the density distribution of the atmosphere. It is formed integrally with the conveyor 12b. Moreover, it divides | segments into the 1st chamber main body 11a1 and the 1st conveyance conveyor 12a which are located in a heating area | region, and the 2nd chamber main body 11a2 and the 2nd conveyance conveyor 12b which are located in a cooling area | region. Therefore, the loss occurrence site can be blocked most effectively.

  As described above, the skirt body 11b and the chamber body 11a divide and cut off (insulate and electrically insulate) the solder bath 15 and the chamber body 11a, and at the top 20 of the chamber body 11a, the first chamber body 11a1 and the first chamber body 11a. Since it is divided into one transfer conveyor 12a, the second chamber body 11a2 and the second transfer conveyor 12b, heat loss due to wasteful heat release can be greatly reduced, and power consumption can be greatly reduced. It becomes like this. As a result, the amount of carbon dioxide generated can be reduced.

  In addition, the location which divides the chamber body 11 is not restricted to embodiment mentioned above. For example, from the temperature distribution, the first chamber body 11a1 may be divided into a region where the preheater 25 is disposed and a region where the solder bath 15 is disposed, and may be integrally formed. That is, the region where the preheater 25 is disposed is a region where the workpiece W is heated to about 90 to 150 ° C., and the temperature of the printed wiring board is about 250 to 260 ° C. in the region where the solder bath 15 is disposed. Therefore, if the first chamber body 11a1 is divided into a region where the preheater 25 is disposed and a region where the solder bath 15 is disposed, the heat loss can be further reduced. That is, by configuring the chamber body and the transfer conveyor so as not to generate heat, the chamber body and the transfer conveyor can be prevented from functioning as a heat dissipation device.

  Moreover, the structure of the skirt body 11b is not restricted to embodiment mentioned above. As shown in FIG. 2, the skirt body 11 b described above is formed in a box shape having four side plates integrated with each other and opened up and down. However, for example, the skirt body may be configured such that each of the four side plates can be divided. The skirt body can be attached and detached without lowering the solder bath by configuring the side plates so that they can be divided and attaching or removing the side plates to the chamber body one by one. In this case, the skirt body is not limited to the four side plates, and may have any configuration.

  The atmosphere shielding soldering apparatus according to the present invention can perform soldering with low power consumption and, consequently, small amount of carbon dioxide generation and no electrical stress applied to the printed wiring board and excellent solder wettability. Therefore, the present invention can be used for a soldering apparatus that can perform high-quality soldering mounting with a small environmental load.

It is a figure which shows the structure of an atmosphere shielding soldering apparatus. It is a perspective view which shows the structure of a skirt body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Chamber body 11a Chamber main body 11a1 1st chamber main body 11a2 2nd chamber main body 11b Skirt body 12 Conveyor 12a 1st conveyer 12b 2nd conveyer 15 Solder tank 16 Molten solder 17 Seal member 18 Seal member 40 Elevator Device (elevating device)

Claims (5)

An atmosphere shielding soldering apparatus configured to perform soldering by bringing a jet wave of molten solder into contact with a workpiece to be soldered in a chamber body that shields the atmosphere,
The chamber body is integrally formed so that a skirt body as an opening of the chamber body is immersed in the molten solder accommodated in the solder bath and can be divided into a plurality of parts.
An atmosphere shielding soldering apparatus, wherein a sealing member having a heat insulating property is interposed at the divided portion.   The atmosphere shielding soldering apparatus according to claim 1, wherein the chamber body is integrally formed so that the skirt body and the chamber body can be divided.   The atmosphere shielding soldering apparatus according to claim 2, further comprising an elevating device that varies a height position of the solder tank.   The atmosphere shielding soldering apparatus according to any one of claims 1 to 3, wherein an electrically insulating layer having erosion resistance against molten solder is formed on a surface of the skirt body. .   The chamber body is integrally formed so that a first chamber body located in the heating region of the work to be soldered and a second chamber body located in the cooling region can be divided, and the chamber The conveyance conveyor arrange | positioned in the body is divided | segmented into the 1st conveyance conveyor located in the said heating area | region, and the 2nd conveyance conveyor located in the said cooling area | region. The atmosphere shielding soldering apparatus according to any one of the above items.

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