JP4012515B2 - Soldering method and soldering apparatus - Google Patents

Description

  The present invention supplies molten solder only to a soldered area of a printed wiring board, that is, a part to be soldered and its peripheral area or a part where a large number of soldered parts are gathered and its peripheral area. The present invention relates to a method and a soldering apparatus for soldering a part to be soldered.

  For example, when an electronic component that cannot be soldered by the reflow soldering method is to be soldered to a printed wiring board that has been reflow soldered, the soldered portion of the electronic component or the peripheral area thereof is to be soldered. The present invention relates to a method and a soldering apparatus for supplying molten solder only to a soldering region and soldering.

  As a technique for performing soldering by supplying molten solder only to a specific soldering area of a printed wiring board, a soldering method by a so-called Sylvania method (see Patent Document 1) is known. In this soldering technique, a nozzle for supplying molten solder is provided at a position corresponding to a specific soldering area of the printed wiring board, and the molten solder is supplied from the position-aligned nozzle to the specific soldering area. Is a technology for supplying solder and soldering.

  In the Sylvania method, the number of nozzles is required as many as the number of areas to be soldered, but there is a soldering technique (see Patent Document 2) in which only one nozzle is required. This soldering technology uses a handling robot to convey the printed wiring board, and applies the molten solder supplied from one nozzle to the printed wiring board to cover the entire surface of the target soldering area and each soldering target. This is a technique for performing soldering by supplying molten solder to the soldering area.

  On the other hand, a mask is provided so that only a specific soldering area of the printed wiring board is exposed, and solder is supplied by a flow-type soldering method with the mask provided, and only to the specific soldering area. A soldering technique for supplying molten solder is also known. And as a mask, there exists a mask plate used for the use of many times besides the tape-shaped member and jelly-shaped member used for the purpose of use only once.

  Here, how a flow type soldering method is performed using a mask plate will be described with reference to the drawings.

  FIG. 15 is a diagram for explaining how the mask plate 200 is provided on the printed wiring board 100. FIG. 15A shows a longitudinal section of the printed wiring board 100, and FIG. FIG. 15C is a diagram for explaining a state in which the mask plate 200 is provided on the printed wiring board 100, and FIG. 15C shows the longitudinal section thereof. That is, FIG. 15C shows a state where the mask plate 200 shown in FIG. 15B is provided on the printed wiring board 100 shown in FIG. The printed wiring board 100 and the like are rectangular in plan view. Reference numeral 101 denotes an IC chip, 102 denotes a shield case, 103 denotes a chip-type electronic component, and 104 denotes a lead-type electronic component.

  15A and 15C, an IC chip 101 and a chip-type electronic component 103 that are surface-mounted on the printed wiring board 100 are electronic components that are already soldered and mounted by a reflow soldering method. The lead-type electronic component (including the connector 105) 104 and the shield case 102 in which the lead terminals are inserted into the 100 are so-called post-installed electronic components that perform soldering by supplying molten solder after reflow soldering. Therefore, the lead terminals of the lead-type electronic component 104 and the terminals of the shield case 102 form the soldered portion 107 between the soldering lands (not shown) formed on the printed wiring board 100, and a set of them. Thus, a soldered region 108 is formed.

  A member that covers an area other than the soldering area 108 and has openings (opening A, opening B, opening C,...) Only in the soldering area 108 is a mask plate shown in FIG. 200.

  That is, as shown in FIG. 15C, by providing a mask plate 200 having an opening at a position corresponding to the soldered area on the printed wiring board 100, only the soldered area 108 is exposed. It becomes possible to form. In this state, molten solder is supplied, that is, soldered.

  FIG. 16 is a view for explaining a mode in which the printed wiring board 100 provided with the mask plate 200 is soldered by the flow type soldering apparatus 800, and is a view seen from the longitudinal section thereof. In the figure, 801 indicates a solder bath, and 802 indicates molten solder.

  The flow type soldering apparatus 800 holds a solder 802 in a molten state in a solder bath 801. Although not shown, the molten solder 802 is maintained at a predetermined temperature determined in advance by a heater, a temperature sensor, a temperature control device, and the like. The molten solder 802 is supplied to the blowing body 803 by a pump 807, and a flow wave 805 of the molten solder 802 is formed in the blowing hole 804.

  At the time of soldering, the printed wiring board 100 provided with the mask plate 200 illustrated in FIG. 15C is transported in the direction of the arrow X by the transport conveyor 400, and the molten solder 802 is sequentially transferred to the soldered area 108. Solder is supplied by bringing the flow wave 805 into contact and supplying solder. In addition, as the transfer conveyor 400, an apparatus having a configuration in which both end portions of the printed wiring board 100 are held by holding claws or the like provided on the chain conveyor is generally used.

  Incidentally, a specific soldering method is known by the method of supplying the molten solder 802. Besides the above-described flow type soldering method, the wave type soldering method, the flat dip type soldering method, and the flow dip type are also used. There are known methods of soldering, etc. For a quick glance of these methods, for example, “Electronic Technology June 1981 Special Extra Number (1981. Vol. 23 No. 7)” is referred to, especially pages 48 to 49. Become.

  Next, these soldering techniques will be compared. In the Sylvania method (Patent Document 1), when the type of the printed wiring board 100 changes, the position and shape of the specific soldered area 108 change, and it is necessary to manufacture a nozzle corresponding to the shape of the area at a corresponding position. There is also a need for replacement work.

  The technique of Patent Document 2 has the advantage that only one nozzle is required, that is, a soldering device having a single configuration, but a handling robot having at least four axes of control coordinates is required as a transport device for the printed wiring board 100. Furthermore, it is necessary to create a transfer program for controlling the handling robot for each printed wiring board. That is, the soldering cost of the printed wiring board 100 is greatly increased.

  On the other hand, the flow type soldering method using the mask plate 200 has an advantage that the soldering apparatus has a single configuration, but the mask plate 200 is prepared for each type of the printed wiring board 100. There is a need to.

Comparing these three soldering techniques, the technique of Patent Document 2 and the technique using the mask plate 200 are superior in that the configuration of the soldering apparatus is a single one. In other words, this is because a great work of changing the configuration of the soldering apparatus for each type of the printed wiring board 100 is unnecessary. Incidentally, since the molten solder 802 is normally maintained at a temperature of about 230 ° C. to 260 ° C., the nozzle replacement operation in the Sylvania method is extremely dangerous.
British Patent No. 801510 Japanese Patent No. 2761204 Electronic Technology June 1981 Special Issue (1981. Vol. 23 No. 7)

  Considering the soldering cost of the printed wiring board 100, the soldering technology of Patent Document 2 using a high-cost transport device such as a handling robot adds a large depreciation cost to the printed wiring board 100 to be soldered and produces There is a problem that causes an increase in cost. From the viewpoint of cost, the soldering method in which the small-sized mask plate 200 is repeatedly used can perform the soldering work of many kinds of printed wiring boards 100 using the soldering apparatus having a single configuration. Excellent in terms.

  However, as with the shield case 102 shown in FIG. 16, the shape is large, and iron or the like is used as the material, and the heat capacity of the electronic component having a large heat capacity is compared with that of a lead type electronic component such as a resistor or an electrolytic capacitor. Thus, it has a heat capacity of about several tens to several hundred times, and the soldered part does not rise in temperature sufficiently during soldering, so that there is a problem that the wettability of solder deteriorates.

  That is, in FIG. 16, when the soldered region 108 of the opening A is in contact with the flow wave 805, the soldered region 108 of the opening B does not contact the flow wave 805. Therefore, the amount of heat supplied to the shield case 102 in contact with the flow wave 805 in the opening A is diffused throughout the shield case 102 to suppress the temperature rise of the soldered portion 107 in the opening A, and as a result, the solder The wettability of the becomes worse. This problem also exists in the technique of Patent Document 2.

  An object of the present invention is a high quality excellent in wettability with respect to an electronic component having a large shape and a large heat capacity in a soldering technique for supplying molten solder to a specific region of a printed wiring board 100 using a mask plate 200. By establishing a soldering method and a soldering apparatus that can perform soldering, it is possible to solder many types of printed wiring boards 100 at low cost and with high quality.

  The present invention is configured such that the printed wiring board 100 provided with the mask plate 200 is brought into surface contact with the solder flow surface 306 of the flow dip type soldering apparatus 300, and the soldered regions 108 are brought into contact with the molten solder 302 all at once. There is a feature.

Held together by fitting ie, a mask plate 200 having an opening at a position corresponding to the soldered regions 108 of the printed wiring board 100 having electronic components mounted on the printed circuit board 100, held together When the printed wiring board 100 and the mask plate 200 are brought into surface contact with the solder flow surface 306 of the flow dip type soldering apparatus 300, the molten solder is brought into contact with all the soldered areas 108 at the same time, and the electronic components 102, 104, 105 was heated in unison Ru configured Tei to supply the molten solder 302.

  As a result, the electronic components 102, 104, and 105 in all the soldered regions 108 are heated at the same time, and even if there is an electronic component having a large shape and a large heat capacity, the electronic component is sufficiently heated and is good. Solder wettability can be obtained.

( 1 ) That is , the mask plate 200 having an opening at a position corresponding to the soldered region 108 of the printed wiring board 100 on which the electronic components 102, 104, and 105 are mounted is fitted to the printed wiring board 100 and held together. Then, the printed wiring board 100 and the mask plate 200 held together are brought into surface contact with the solder flow surface 306 of the flow dip type soldering apparatus 300 to simultaneously melt the solder into the soldering regions 108 of all the soldered portions 107. 302 is a soldering method configured to contact and supply 302, and when the integrally held printed wiring board 100 and the mask plate 200 are separated from the solder flow surface 306, the integrally held printed wiring board 100 is provided. changing the horizontal position of the other side only one side of the mask plate 200 with And the solder flow surface 306 and the printed wiring board flow surface 306 and solder the object soldered area 108 while forming a peel back the contact portion between the soldering region 108 of the 100 by disengaging raised from the solder flow surface 306 to And the printed wiring board 100 and the mask plate 200 are moved only when the last soldered area 108 is detached from the solder flow surface 306 as the printed wiring board 100 and the mask plate 200 are separated from each other. This is a soldering method in which conveyance is started also in the direction of inclination and the peel back is separated from the soldered region 108.

  As a result, even if the flow dip type soldering method is employed using the mask plate 200, a peel-back is formed, and even if the soldered portion 107 is formed at a fine pitch, the solder releasability is achieved. And no solder bridge failure occurs. Also, when the solder bridge failure is most likely to occur, the printed wiring board 100 is transported along the inclined elevation angle direction, that is, along the plate surface, thereby further improving the solder detachability and ensuring the solder bridge failure. Can be prevented.

( 2 ) In the soldering method of (1 ), the printed wiring board 100 held integrally and the printed wiring board 100 held integrally during surface contact of the mask plate 200 to the solder flow surface 306 In this soldering method, only one end side of the mask plate 200 is temporarily detached from the surface contact so that the surface contact is intermittently maintained.

  As a result, the gas generated upon contact with the solder can be released and released from the opening of the mask plate 200, and the surface contact between the soldered region 108 and the solder flow surface 306 is ensured. It becomes like this. Then, when it is necessary to sufficiently degas, the up and down operation of the printed wiring board 100 may be repeated.

( 3 ) Further, in the soldering method of ( 1 ) or ( 2 ), the opening shape of the mask plate 200 corresponding to the peelback moving direction in the soldered region 108 of the printed wiring board 100 is matched with the flow-down direction of the peelback. The soldering method is formed so as to have an inclined opening shape so as not to cause a sudden change in the flow direction of the peeling of the peelback from the soldered region 108.

  As a result, the peel-down movement of the peelback is not hindered, and better solder detachability can be obtained.

( 4 ) On the other hand, a flow dip type soldering apparatus having a solder flow surface larger than the outer dimensions of the printed wiring board 100, and a mask plate 200 having an opening in a target soldered area 108 of the printed wiring board 100. And the printed wiring board 100 in a state of being fitted together, and in the surface direction of the solder flow surface, in a direction perpendicular to the surface direction and in an elevation direction with respect to the surface direction. All of the soldered regions 108 are brought into surface contact with the solder flow surface by the conveying means for controlling and conveying the position and posture of the printed wiring board 100, and the integrally held printed wiring board 100 and the mask plate 200. Printed wiring board 100 and mask plate 200 which are held together after contacted with molten solder all at once. Withdrawal while forming a peel back the contact portion of one end only without changing the horizontal position of the other end side and the soldered area 108 of the by disengaged raised from the solder flow surface solder flow surface and the printed wiring board 100 of the The transport having the sequence or the program for starting transporting the printed wiring board 100 and the mask plate 200 which are held together only when the last soldered area 108 is detached from the solder flow surface in the inclined elevation direction. It is the soldering apparatus comprised so that the control apparatus of a means might be provided.

Thereby, the soldering method of said ( 1 ) and the soldering apparatus which implement | achieves the effect | action are obtained.

( 5 ) In the soldering apparatus according to (4), the control device of the conveying means brings the printed wiring board 100 and the mask plate 200 held together into surface contact with the solder flow surface to all the soldered regions 108. A sequence or program for temporarily leaving the surface contact by temporarily separating the printed wiring board 100 and the mask plate 200 that are integrally held when they are in contact with the molten solder all at once. It is the soldering apparatus comprised in this.

Thereby, the soldering method of said ( 2 ) and the soldering apparatus which implement | achieves the effect | action are obtained.

  Thus, according to the soldering method and the soldering apparatus of the present invention, the printed circuit board that has already undergone reflow soldering has a large shape and a large heat capacity, such as an electronic component such as a shield case or a heat sink. For example, when soldering an electronic component having a heat capacity of about several tens to several hundred times as large as that of a lead-type electronic component such as a resistor or an electrolytic capacitor, a molten solder is supplied and referred to as a so-called retrofit. Even when soldering, it is possible to increase the temperature by supplying a sufficient amount of heat to the electronic component, and to perform soldering with good solder wettability, and to perform soldering without a solder bridge Is possible. As a result, it is possible to manufacture various types of printed wiring boards by soldering with high quality at low cost.

  The soldering method of the present invention can be realized by the following configuration and procedure.

(1) Configuration of Mask Plate 200 FIG. 1 is a diagram for explaining the configuration of the mask plate 200, and FIGS. 15 (a), (b), and (c) are FIGS. 1A shows a longitudinal section of the printed wiring board 100, FIG. 1B shows a longitudinal section of the mask plate 200, and FIG. 1C shows a mask plate on the printed wiring board 100. The longitudinal section is shown in the figure explaining the state in which 200 is provided. That is, FIG. 1C shows a state where the mask plate 200 of FIG. 1B is provided on the printed wiring board 100 of FIG.

  The mask plate 200 is different from the conventional mask plate 200 of FIG. 15 in that a peel-back forming portion 106 is provided in the opening (opening a, opening b, opening c). The peel back forming portion 106 is provided as a surface that is inclined (not vertical as in the prior art) with respect to the surface of the printed wiring board 100, and the inclined surface is a movement direction of the peel back described later, that is, a molten solder. 302 (FIG. 2) is provided so as to be inclined with respect to the moving direction Z (FIG. 3) of the separation point when separating from the printed wiring board 100.

  That is, as a peel back, the molten solder 302 can be smoothly detached without hindering the movement of the molten solder 302 when it is separated from the printed wiring board 100 and thus the flow of the molten solder 302.

(2) Procedure of Soldering Method FIGS. 2 and 3 are diagrams for explaining a procedure for realizing the soldering method of the present invention, and the procedure is (a) → (b) → (c) in FIG. 2. → Realized by the steps of (a) → (b) → (c) in FIG. It should be noted that there is no reason why this procedure is divided into FIGS. 2 and 3 except that FIG. 2 and FIG. 3 cannot be included in one drawing.

  2 and 3 show a printed wiring board 100 provided with the mask plate 200 shown in FIG. 1C and a flow dip type soldering apparatus 300. FIG. In this flow dip type soldering apparatus, a molten solder (molten solder) 302 is held in a solder bath 301, and the molten solder is heated to a predetermined temperature by a heater, a temperature sensor, and a temperature control device. Maintained. The molten solder is supplied to the blower body 303 by a pump 307 and a flow surface 306 of the molten solder is formed on the blower 304.

  Here, the characteristic configuration of the flow dip type soldering apparatus is that the size of the air outlet 304 of the air outlet body 303 is larger than the size of the printed wiring board to be soldered, and the air outlet 304 is held in a horizontal plane. The molten solder liquid surface, that is, the flow surface 306 is formed, and the molten solder 302 on the flow surface 306 is flowing in the direction in which the molten solder 302 overflows from the blower port 304 of the blower body 303. It is. Therefore, fresh solder is always supplied to the air outlet as in the flow type soldering apparatus, and the flow surface 306 of the molten solder 302 having a stable temperature is formed.

  Next, the procedure for realizing the soldering method of the present invention will be described with reference to FIGS.

[Step 1]
As shown in FIG. 2A, the printed wiring board 100 provided with the mask plate 200 is conveyed onto the flow surface 306 of the flow dip type soldering apparatus 300. In this case, it is desirable that the board surface of the printed wiring board 100 be held horizontally in the same manner as the flow surface 306.

[Step 2]
As shown in FIG. 2B, one end side of the printed wiring board 100, that is, one end side that becomes the peel-back forming portion 106 side of the mask plate 200 is lowered in the direction of arrow D, and the flow surface 306 of the molten solder 302 becomes It is immersed to the extent that it does not overflow to the board surface above the printed wiring board 100.

[Step 3]
As shown in FIG. 2C, the other end side of the printed wiring board, that is, one end side opposite to the peel-back forming portion 106 side of the mask plate 200 is lowered in the direction of arrow E, and the flow of the molten solder 302 is performed. The surface 306 is immersed to the extent that it does not overflow to the upper surface of the printed wiring board 100, and the entire lower surface of the printed wiring board 100, of course, except for the masking area of the mask plate 200, melts all of the openings. The solder is brought into contact with the flow surface 306 and this surface contact state is maintained for a predetermined time.

  In this case, all the soldered portions 107 of so-called post-attached electronic components such as the lead-type electronic components 104 and 105 and the shield case 102 are heated all at once by the molten solder 302, and the electronic components have a large shape and a large heat capacity. Even immediately, the temperature rises to the molten solder temperature or a temperature near it, and good solder wettability can be obtained.

  When the surface contact state is maintained and maintained, the one end side of the printed wiring board 100 is temporarily raised and then immediately lowered to maintain and maintain the surface contact state, thereby intermittently maintaining the surface contact state. By maintaining and maintaining, the gas generated by the contact with the solder can be released and released from the opening of the mask plate 200, and the surface contact can be reliably performed. This temporary ascending / descending operation may be performed a plurality of times.

[Step 4]
As shown in FIG. 3A, the other end side of the printed wiring board 100 described in step 3, that is, one end side opposite to the peel back forming portion 106 side of the mask plate 200 is raised in the direction of arrow F. The separation of the flow surface 306 of the molten solder 302 and the soldered area 108 of the printed wiring board 100 is started.

  The separation of the flow surface 306 of the molten solder 302 from the printed wiring board 100 and the soldered area 108 is performed while peeling back at the separation boundary, and the peeling back is performed while moving in the arrow Z direction. Is done. Therefore, even if there are fine-pitch soldered portions in which the soldered portions are arranged at a narrow interval, a solder bridge does not occur.

  In addition, since the peel-back forming portion 106 is provided on the mask plate 200, the peel-back solder is released while flowing smoothly along the inclined surface of the peel-back forming portion 106, thereby reliably preventing the occurrence of solder bridges. be able to.

[Step 5]
As shown in FIG. 3B, as the printed wiring board 100 rises in the direction of arrow F in step 4, it becomes one end side of the printed wiring board 100 described in step 2, that is, the peel back forming side of the mask plate 200. When the peelback moves to one end side and the molten solder, that is, the peelback is removed from the last soldered area, the printed wiring board 100 is also conveyed in the inclined elevation angle direction, that is, the arrow G direction, and the peelback is released. The solder is finally released from the last soldered region where molten solder is likely to accumulate. As a result, solder bridges do not occur in the soldered portion of the last soldered region where solder bridges are most likely to occur.

  That is, in step 5, the rising in the direction of arrow F and the conveyance in the direction of arrow G are performed together.

[Step 6]
When the printed wiring board 100 is completely removed from the flow surface in step 5, the one end side of the printed wiring board 100 described in step 2, that is, the one end side serving as the peel-back forming portion side of the mask plate 200 is raised in the arrow H direction. And complete the soldering operation.

  Next, how the soldering method and the soldering apparatus of the present invention can be practically realized as a soldering system will be described in an embodiment.

(1) Configuration Example of Mask Plate 200 FIG. 4 is a diagram for explaining an example of the mask plate 200, (a) is a perspective view seen from the solder contact surface side, and (b) is the opposite side to (a). It is the perspective view which showed the clamper part especially in a part of the side by which a printed wiring board is fitted in the surface. Note that the openings a, b, and c are openings corresponding to the openings a, b, and c shown in FIGS.

  The mask plate 200 is formed by processing a material obtained by solidifying carbon fibers with a heat-resistant resin into a desired shape by cutting or the like. The mask plate 200 has a small heat capacity and is resistant to a soldering temperature. Even though it is considered to be usable.

  An opening a, an opening b, an opening c,... Opening m, and an opening n are provided corresponding to the soldered area of the printed wiring board 100, and each opening has a peel back forming portion, that is, a mask plate. An opening surface which is not perpendicular to the plate surface of 200 but is inclined is formed. As shown in FIG. 3A, the inclination direction of the peel-back forming portion 106 is provided so that the opening becomes large at least on the side that becomes the movement direction of the peel-back. Moreover, the conveyance holding part 202 is provided in the both-sides edge part of the mask plate 200, and it is the mechanism which hold | maintains and conveys this conveyance holding part to a conveyance conveyor. In addition, you may comprise the part of this conveyance holding | maintenance part 202 with another members, such as a metal member different from the mask plate 200. FIG.

  On the other hand, as shown in FIG. 4B, the mask plate 200 is provided with a printed wiring board fitting portion in which the printed wiring board is fitted into the recess, and the printed wiring board is fitted into the transport holding portion. A clamper for holding the joint is provided. As shown in the figure, the clamper rotates the knob 201 in the direction of arrow I to rotate the clamp bar in the direction of arrow J to move the printed wiring board onto the printed circuit board. It is the structure pushed down. As a result, the printed wiring board is held integrally with the mask plate 200. This clamper is usually provided at about four locations.

(2) Configuration Example of Soldering System FIGS. 5, 6, and 7 are diagrams illustrating an example of a soldering system. FIG. 5 is a vertical cross-sectional view of the main part of the soldering system. FIG. 6A is a diagram showing a main part viewed from the II cross section (transverse cross section) in FIG. 5, FIG. 6B is a diagram for explaining another example of the transport and holding part of the mask plate, and FIG. It is a block diagram which shows the control system of a sticking system. Here, the plate-like member shown as the printed wiring board in FIG. 5 is shown by omitting the printed wiring board 100 that is integrally held by the mask plate 200 described in the above (1).

  This soldering system includes a flux application process, a preheating process, and a soldering process in the order of the processes. The first transport conveyor 501, the second transport conveyor 502, and the third are provided independently in each process. The conveyors 503 are arranged in order so that the printed circuit board 100 can be conveyed and delivered. As illustrated in FIG. 6, these conveyors are configured to convey the printed wiring board 100 held on the pins when the conveyor chain rotates in the conveyor frame 604. . The guide plate 601 is a member for regulating the position of the printed wiring board 100 in the lateral direction.

  In addition, a position sensor for specifying the waiting time for carrying in the printed wiring board 100 and a transfer position is provided along each conveyor, and a first position sensor 504 for detecting the waiting time for loading the printed wiring board 100, a flux application step The second position sensor 505 for stopping the printed wiring board 100 conveyed to the predetermined position, the third position sensor 506 for stopping the printed wiring board 100 conveyed to the preheating process at the predetermined position, and the soldering process A fourth position sensor 507 for detecting the presence or absence of the printed wiring board 100 during soldering, and a fifth position sensor 508 for temporarily retracting the printed wiring board 100 conveyed to the soldering process to a predetermined position. It is provided.

  In the flux application step, a flux spray nozzle 509 is provided at a position below the first conveyor 501 and connected to a flux supply tank (not shown in detail) via an electromagnetic valve 510. The flux in the flux supply tank is pressurized by air having a constant pressure, and the spray nozzle 509 is supplied with a constant pressure flux to spray the spray flux 511. Accordingly, the amount of flux accumulated depending on the length of time for which the electromagnetic valve 510 is opened is applied to the printed wiring board 100. As another technique, a flux flow meter may be provided and the flow rate may be integrated and applied up to a predetermined amount.

  Further, an exhaust hood 514 provided with a filter 512 and an exhaust fan 513 is provided above the first transport conveyor 501, thereby constituting an exhaust means. That is, the spray flux that has not been applied to the printed wiring board 100 is guided and sucked by the exhaust hood 514 and is exhausted after being captured by the filter 512.

  In the subsequent preheating process, an infrared heater 515 is provided below the second conveyor 502, and a surface temperature sensor 516 for detecting the surface temperature is provided. That is, it is a mechanism that heats the printed wiring board 100 from the lower surface while maintaining the surface temperature of the infrared heater 515 at a predetermined temperature by a control device to be described later. Thereby, the applied flux can be activated and dried.

  A blower hood 520 provided with an atmosphere heater 517, a blower fan 518, and a blower guide plate 519 is provided above the second conveyor 502, and further, together with the ambient temperature sensor 521, constitutes a hot air heating means. ing. That is, it is a mechanism that heats the printed wiring board 100 from the upper surface while maintaining the hot air temperature at a predetermined temperature by a control device described later. As a result, the lead-type electronic component can be actively preheated.

  In the final soldering step, a flow dip type soldering apparatus 300 is provided below the third conveyor 503, and the solder held in the molten state in the solder tank 301, that is, the molten solder 302 is pumped 307. As a result, the blower body 303 overflows and the flow surface 306 of the molten solder 302 is formed on the blower hole 304. The solder in the solder bath 301 is maintained at a predetermined temperature by a heater (not shown), a temperature sensor, and a dedicated temperature control device. Moreover, the baffle plate (perforated plate) 521 in the blower body 303 is a member for adjusting the flow of solder.

  Further, the third conveyor 503 has a front actuator 522 and a rear actuator 523 provided on the frame so that the carry-out side (front side) is in the arrow K direction and the carry-in side (rear side) is the arrow N. It can be moved up and down in the direction. In other words, by separately controlling the expansion and contraction amounts of these actuators, the vertical conveyance position and the inclination amount of the third transport conveyor 503 and thus the printed wiring board 100 can be controlled.

  The front actuator 522 and the rear actuator 523 are coupled to the third transport conveyor 503 by a pin 527 so that the third transport conveyor 503 can be rotated in the directions of the arrow M and the arrow O, and the front actuator 522 is provided on the conveyor frame so as to be rotatable in the arrow L direction.

  Furthermore, the rear end (carry-in side end) of the printed wiring board 100 held on the third transport conveyor 503 is pushed, and transport for sliding the printed wiring board 100 on the third transport conveyor 503 is performed. A bar 524 is provided in an advance / retreat actuator 525 that moves the transfer bar in the direction indicated by the arrow P, that is, in the vertical direction. It is provided to be movable in the direction. Therefore, the forward / backward actuator 525 and the transport actuator 526 can freely move the transport bar 524 in the arrow P direction (up and down direction) and the arrow Q direction (transport direction of the printed wiring board 100).

  Further, as shown in FIG. 5 and particularly FIG. 6A, a pressing bar 602 for pressing and fixing the printed wiring board 100 onto the pins of the conveyor is provided on the conveyor frame 604 via a standing tool. The presser actuator 603 is provided. That is, the printed wiring board 100 transported onto the third transport conveyor 503 can be pressed and fixed onto the pins of the transport conveyor by the pressing bar 602 that moves in the arrow R direction. This fixing is performed so that the printed wiring board 100 is pressed to the extent that the printed wiring board 100 is not lifted from the conveyance conveyor. When the rear end of the printed wiring board is pushed by the conveyance bar 524, the printed wiring board can slide on the conveyance conveyor. Press down with force.

  Further, as shown in FIG. 6A, the conveyor frame 604 is provided with a conveyor cover 605, and the transport chain that travels in the return path, and thus the pins and guide plates of the transport conveyor overflow from the air outlet 304 of the air outlet body 303. Shields from flowing molten solder. In addition, as illustrated in FIG. 6B, the position of the printed wiring board 100 can be held downward by forming the conveyance holding portion 202 of the mask plate 200 in a step shape. The molten solder overflowing from the blower 304 of the blower body 303 does not come into contact with the pins or the like of the transport chain, and it is possible to prevent solder adhesion and the like.

  Next, the control system shown in FIG. 7 will be described. The control device 700 is configured by a computer system, and includes a display unit 701 such as an LCD and an instruction operation unit 702 such as a keyboard. The input / output ports are communicably connected to detection means such as sensors and control target means such as actuators.

  As the sensors, the first position sensor 504 to the fifth position sensor 508 described above, the ambient temperature sensor 521, the surface temperature sensor 516, and the liquid level sensor for measuring the height of the solder flow surface 306 shown in FIG. 500 is connected to the control device 700 so that the detected measurement content can be communicated.

  The first transfer conveyor 501, the second transfer conveyor 502, and the third transfer conveyor 503 are connected to the control device 700 so that the transfer direction and transfer speed can be controlled and can be controlled by communication. .

  Further, the front actuator 522, the rear actuator 523, the transport actuator 526, the advance / retreat actuator 525, and the pressing actuator 603 can control the extension direction and extension speed, and are connected to the control device 700 so that they can be controlled by communication. is there.

  The pump 307 can control the rotational speed and thus the supply flow rate of the molten solder to the nozzle, and is connected to the controller 700 so that it can be controlled by communication. Accordingly, the control device 700 can control the height of the flow surface by operating and stopping the pump and controlling the speed.

  The operation and stop of the exhaust fan 513 can be controlled, and the exhaust fan 513 is connected to the control device 700 so that they can be controlled by communication. Further, the solenoid valve 510 can be controlled to open and close, and thus spray and stop the flux, and is connected to the control device 700 so that they can be controlled by communication.

  The infrared heater 515 and the atmosphere heating heater 517 can control the power supplied, and thus the surface temperature of the infrared heater 515 and the atmosphere temperature of the hot air, and the blower fan 518 can control the operation and stop thereof, and can be controlled by communication. It is connected to the control device 700 so that it can be controlled.

(3) Printed Wiring Board Soldering Procedure The control device 700 that controls the operation of the soldering system is configured by a computer system. Therefore, the soldering procedure of the printed wiring board 100 can be realized on the software of the computer system. Note that the surface temperature and hot air temperature of the infrared heater 515 and the height of the flow surface of the molten solder are controlled by the control device 700 by a well-known feedback control method, and therefore description of the control procedure is omitted. The control device 700 is managed by a time sharing system, and each operation is processed in parallel in real time.

  The flowcharts shown in FIGS. 8 to 11 are flowcharts for explaining the work procedure of each process. The flags F1 and F2 used in these flowcharts are initialized to ON when the soldering system is activated.

  FIG. 8 is a flowchart for explaining the work procedure of the flux application process. That is, referring to the first position sensor signal in step S1, it is determined whether or not the printed wiring board is in a carry-in standby state. If it is in a carry-in standby state, the process proceeds to step S2. In step S2, the flag F1 is referred to, and it is determined whether or not conveyance of the printed wiring board on which flux application has been completed (no printed wiring board in the initial state) to the preheating process is permitted. If permitted (flag F1 ON), the process proceeds to step S3.

  In step S3, the first conveyance conveyor is driven and the second position sensor signal is referenced to match the front end position with the second position sensor as viewed from the conveyance direction of the printed wiring board. Thereafter, the process proceeds to step S4, and the preheating process of the printed wiring board, that is, the conveyance to the next process is not permitted (flag F1 OFF).

  Then, it transfers to step S5, opens a solenoid valve over the time corresponding to the predetermined predetermined flux application quantity, and sprays a flux. The solenoid valve is closed after a predetermined time. Thereafter, the process proceeds to step S6, the conveyance of the printed wiring board to the preheating process is permitted (flag F1 ON), the process returns to step S1, and the above procedure is repeated.

  FIG. 9 is a flowchart for explaining the work procedure of the preheating step. That is, in step S11, the flag F1 is referred to, and it is determined whether or not the printed wiring board is waiting in the flux application process. Then, when waiting, the process proceeds to step S12, and with reference to the flag F2, it is determined whether or not the preheating start of the printed wiring board is permitted. The content of this flag F2 is controlled during the work procedure of the soldering process described later, and when the printed wiring board 100 can be transported to the soldering process at the time when the preheating of the printed wiring board is completed, that is, the soldering work is completed. Only when this is done, the flag F2 is set to ON.

  That is, in a predetermined heating state (predetermined surface temperature of a predetermined infrared heater, hot air temperature and wind speed), after a certain period of time, that is, after a predetermined time (specified in advance by measurement). This is because the preheating temperature of the printed wiring board reaches the target temperature after time). That is, it is just good if the printed wiring board is transported to the soldering process after the predetermined time, but the subsequent soldering process needs to be in a state where the printed wiring board can be transported.

  Thus, when the flag F2 is ON, the process proceeds to step S13, and the first conveyance conveyor and the second conveyance conveyor are driven to convey the printed wiring board to the preheating step. Further, the front end position of the printed wiring board is matched with the third position sensor with reference to the third position sensor signal. Thereafter, the process proceeds to step S14, where the printed wiring board is preheated over the predetermined time, and preheated to the target temperature.

  And it transfers to step S15, drives a 2nd conveyance conveyor and a 3rd conveyance conveyor, and conveys the printed wiring board which completed preheating to a soldering process. After that, it returns to step S11 and repeats the above procedure.

  10 and 11 are flowcharts for explaining the work procedure of the soldering process. Since this flowchart cannot be contained in one figure, it is a flowchart divided into FIG. 10 and FIG. 11 through * 1 and * 2. This flowchart is the gist of the embodiment of the present invention.

  On the other hand, FIGS. 12 to 14 illustrate the work procedure shown in FIGS. 10 and 11, and these FIGS. 10 and 11 and FIGS. 12 to 14 will be described in combination. 12 to 14, the soldering operation is as shown in FIG. 12 (a) → (b) → (c) → (d) → FIG. 13 (a) → (b) → (c) → (d) → The process proceeds in the order of FIG. 14 (a) → (b) → (c). 12 to 14, the plate-like member indicated as a printed wiring board is illustrated by omitting the printed wiring board that is integrally held by the mask plate 200 as in FIG. 5.

  That is, in step S21, it is determined whether or not the preheating of the printed wiring board has been completed with reference to step S14 in FIG. 9, and when completed, the process proceeds to step S22 and the printed wiring board in which the preheating has been completed is determined. Transport to soldering process. That is, in conjunction with step S15, the second and third conveyors are driven to align the front end position of the printed wiring board with the fifth position sensor (see FIG. 12A: arrow XR).

  Subsequently, the process proceeds to step S23, where preheating of the printed wiring board is not permitted (flag F2 OFF). Thereafter, the process proceeds to step S24, where the forward / backward actuator is driven to lower the transport bar (see FIG. 12B: arrow PD).

  Thereafter, the process proceeds to step S25, where the third conveyor is driven in reverse to convey the printed wiring board backward, and the rear end thereof is brought into contact with the conveyor bar (see FIG. 12C: arrow XL). Note that this abutting work can be reliably performed by carrying back by a predetermined distance or more.

  Then, it transfers to step S26, drives a pressing actuator, and fixes a printed wiring board to a 3rd conveyance conveyor with a pressing bar (refer FIG.12 (d): arrow RD). In step S26, the pump of the flow dip type soldering apparatus is started to drive, and the flow surface of the molten solder is formed at a predetermined height.

  Then, when preparation for soldering is completed, the process proceeds to step S27, and the preheating start of the printed wiring board is permitted (flag F2 ON). That is, if preheating of the printed wiring board is started from this time, all the soldering operations in the steps described later are completed at the preheating completion time.

  Thereafter, the process proceeds to step S28, the rear actuator is driven to lower the rear end of the printed wiring board, and the rear end of the printed wiring board is brought into contact with the flow surface of the molten solder (see FIG. 13A: arrow ND). . Subsequently, the process proceeds to step S29, where the front actuator is driven to lower the front end of the printed wiring board, and the flow of molten solder is applied to the entire lower surface of the printed wiring board, that is, the surface where the soldered area is present. The surface is brought into contact (see FIG. 13B: arrow KD). In practice, only the area to be soldered of the printed wiring board is brought into contact with the flow surface of the molten solder by the mask plate.

  Then, the process proceeds to step S30, and the soldered area of the printed wiring board is kept in contact with the molten solder flow surface for a predetermined time. In this case, if the front actuator or the rear actuator is driven, the front end or the rear end of the printed wiring board is temporarily raised and then immediately lowered, and the surface contact state is intermittently maintained. It is easy to escape and release the gas generated from the contact surface, and the surface contact between the printed wiring board and the solder flow surface can be more reliably performed. This intermittent operation may be performed a plurality of times.

  In this way, after the predetermined time has elapsed after the surface contact between the printed wiring board and the solder flow surface has elapsed, the process proceeds to step S31, the front actuator is driven to raise the front end of the printed wiring board, and the molten solder Detachment of the printed wiring board from the flow surface is started (see FIG. 13C: arrow KU).

  In subsequent step S32, when the printed wiring board is detached (see FIG. 13D: arrow KU) and the printed wiring board is raised to a predetermined programmed position, the transport actuator is driven. Then, the rear end of the printed wiring board is pushed by the conveying bar and is slid on the conveying conveyor (see FIG. 13D: arrow QR), and the printed wiring board is separated from the flow surface of the molten solder. In step S32, driving of the front actuator and driving of the transport actuator are performed together.

  When the printed wiring board is separated from the flow surface of the molten solder, the process proceeds to step S33, the rear actuator is driven to raise the rear end of the printed wiring board, and the third conveyor is returned to the home position (FIG. 14 (a ) Reference: arrow NU). Then, the process proceeds to step S34, in which the pressing actuator is driven to retract the pressing bar (see FIG. 14B: arrow RU), and the forward / backward actuator is driven to retract the conveying bar (see FIG. 14B): Further, the conveyance actuator is driven to return the conveyance bar to the home position (see FIG. 14B: arrow QL).

Finally, the process proceeds to step S35, the third conveyor is driven, the printed wiring board is carried out, and all the soldering operations are completed (see FIG. 14C: arrow X _R ). Then, it returns to step S21 and repeats the above procedure.

  In this way, the entire lower surface of the printed wiring board, of course, except for the masking area of the mask plate, all the openings are brought into contact with the molten solder flow surface, and this surface contact state is maintained for a predetermined time. By maintaining all soldered parts of so-called post-installed electronic components such as lead-type electronic components and shield cases, all of the soldered parts are heated by molten solder all at once. The temperature rises to or near the temperature, and good solder wettability is obtained.

  Further, the separation of the flow surface of the molten solder from the printed wiring board and the soldered area is performed while peeling back at the separation boundary, and the peeling is performed while moving in the arrow Z direction. . Therefore, even if there are fine-pitch soldered portions in which the soldered portions are arranged at a narrow interval, a solder bridge does not occur. Moreover, when the last peelback is released, the printed wiring board is also conveyed in the direction of the inclined elevation angle, that is, in the direction of the arrow G, so that the peeling of the peelback is promoted and the solder from the last soldered area where molten solder tends to accumulate Is finally released, so that no solder bridge is generated in the soldered portion of the last soldered region where solder bridging is most likely to occur.

  Among the mounting technologies that promote the miniaturization of electronic devices, the soldering technology in this field has shifted to the so-called micro soldering technology, and the mainstream of the soldering technology has shifted to the reflow soldering technology. However, there are many electronic components that cannot be reflow soldered by all means, and the soldering is performed on the corresponding soldered part of the printed wiring board on which reflow soldering has been completed or the soldered area that is a group of the soldered parts. Realized by supplying molten solder.

  The technology of the present invention makes it possible to supply such a molten solder to perform soldering of a specific soldered portion or a soldered area, and has a very large heat capacity as compared with a normal electronic component. Even for electronic parts and large-sized electronic parts, uniform soldering to achieve good solder wettability without causing solder bridging defects. It becomes possible to support strongly.

It is a figure for demonstrating the structure of a mask plate. It is a figure for demonstrating the procedure which implement | achieves the soldering method of this invention. It is a figure for demonstrating the procedure which implement | achieves the soldering method of this invention. It is a figure for demonstrating the example of the mask plate in this invention. It is a figure for demonstrating the principal part of the soldering system by this invention. It is a figure for demonstrating the principal part of the soldering system by this invention. It is a block diagram which shows the control system of the soldering system by this invention. It is a flowchart explaining the work procedure of the flux application | coating process in this invention. It is a flowchart for demonstrating the work procedure of the preheating process of the soldering system by this invention. It is a flowchart explaining the work procedure of the soldering process in this invention. It is a flowchart explaining the work procedure of the soldering process in this invention. It is a figure for demonstrating the operation | work procedure of this invention. It is a figure for demonstrating the operation | work procedure of this invention. It is a figure for demonstrating the operation | work procedure of this invention. It is a figure for demonstrating the relationship between a printed wiring board and a mask plate. It is a figure explaining the aspect which solders the printed wiring board provided with the mask plate with a flow type soldering apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Printed wiring board 101 IC chip 102 Shield case 103 Chip-type electronic component 104 Lead-type electronic component 105 Connector 106 Peel back formation part 107 Soldering part 108 Soldering area 200 Mask plate 300 Flow dip type soldering apparatus 301 Solder tank 302 Molten solder 303 Blow hole body 304 Blow hole 305 Flow wave 306 Flow surface 307 Pump

Claims (5)

A mask plate having an opening for supplying molten solder to a position corresponding to a soldered region of a printed wiring board on which electronic components are mounted is fitted and held integrally with the printed wiring board,
By supplying the integrally held printed wiring board and mask plate to the solder flow surface of the flow dip type soldering device, the molten solder is brought into contact with the soldering areas of all the soldered parts at the same time. And
Subsequently, when the integrally held printed wiring board and the mask plate are separated from the solder flow surface, only the one end side of the integrally held printed wiring board and the mask plate is changed without changing the horizontal position of the other end side. The soldering area and the solder flow surface are separated while forming a peelback at the contact portion between the solder flow surface and the soldered area of the printed wiring board by raising the solder flow surface.
The printed wiring board and the mask plate are transported also in the inclined elevation angle direction only when the last soldered area is detached from the solder flow surface as the one end side of the printed wiring board and the mask plate rises. Starting and releasing the peelback from the soldered area;
Soldering method characterized by In soldering method according to claim 1 Symbol placement, temporarily only one end of the held printed wiring board and the mask plate to the integral during surface contact to the solder flow surface of the printed wiring board and the mask plates held together To leave the surface contact intermittently and maintain the surface contact intermittently,
Soldering method characterized by 3. The soldering method according to claim 1 or 2 , wherein a peelback forming portion that is inclined in accordance with the flow-down direction of the peelback is formed in the opening of the mask plate that corresponds to the moving direction of the peelback in the soldered region of the printed wiring board. Providing that the flow direction of separation of the peelback from the soldered area is not suddenly changed;
Soldering method characterized by A flow dip type soldering apparatus having a blower body that flows in a direction in which molten solder overflows and having a solder flow surface that is larger than the outer dimensions of the printed wiring board, and intended soldering of the printed wiring board The mask plate having an opening in the region and the printed wiring board are transported in a state of being fitted together, and at least the surface direction of the solder flow surface and the position of the printed wiring board in the direction perpendicular to the surface direction After conveying means for controlling the posture, the integrally held printed wiring board and the mask plate are brought into surface contact with the solder flow surface, and all the soldered areas are brought into contact with the molten solder all at once. Only one end of the printed wiring board and the mask plate held together is separated from the solder flow surface without changing the horizontal position of the other end. The solder flow surface and the soldered area of the printed wiring board are separated from each other while forming a peelback, and the last soldered area is detached from the solder flow surface. Comprising a control device for the conveying means having a sequence or a program for starting conveyance of the printed wiring board and the mask plate also in the direction of the inclined elevation angle thereof,
Soldering device characterized by 5. The soldering apparatus according to claim 4, wherein the control device of the conveying means brings the printed wiring board and the mask plate held together into surface contact with the solder flow surface so that all the soldered areas are simultaneously melted solder. A sequence or program for temporarily maintaining the surface contact intermittently by temporarily removing only one end of the printed wiring board and the mask plate from the surface contact while being in contact with each other;
Soldering device characterized by

Images