JP6184451B2 - Jet-type soldering device and solder separation control method in jet-type soldering device - Google Patents

Description

  The present invention relates to a jet-type soldering device and a solder detachment control rod attached to the jet-type soldering device. More specifically, the present invention relates to a jet-type soldering device and a jet-type soldering device that can suppress the occurrence of bridges and icicles. The present invention relates to a solder removal control rod to be attached.

  There are two types of electrical components that are soldered to a printed circuit board: surface mount type and lead type. Lead-type electrical components are generally soldered with a jet-type soldering device that moves the molten solder surface. In a general jet-type soldering apparatus, as shown in FIG. 11 of Patent Document 1 (Japanese Patent Laid-Open No. 2000-22323) and as shown in FIG. 4A, the flux application step S1 and the printed board P are heated. Heating process S2, the first jet soldering process S3 for injecting molten solder into details such as soldering and through-holes to chip parts with strong waves blown up, remelting bridges and tiles with a gentle jet The secondary jet solder process S4 for removing unnecessary solder and the cooling process S5 for cooling the printed circuit board P are performed in this order.

  In the primary jet solder process S3, in order to eliminate unsolder, a strong wave is generated in which molten solder is blown up. Solder with strong waves blown up cannot be soldered cleanly, and soldering defects such as so-called tsura where the solder adheres to the tip of the lead and so-called bridges where the solder straddles between the leads occur. . In addition, in the home appliance industry and the like, through-holes that are difficult to receive solder are usually passed if solder enters to a depth of 70%, but in the automobile industry and the like where even more stringent quality is required, 100% depth is required. The For this reason, if an attempt is made to satisfy this requirement by making the molten solder into a rougher wave or the like, the occurrence of soldering defects such as bridges in the primary jet soldering step S3 increases.

  Then, although bridges and wiggles are removed in the next secondary jet soldering step S4, it is difficult to completely remove them. As a main factor that bridges and wiggles remain, there is an inappropriate heating time in the secondary jet solder process S4. If the heating time is short, the temperature of the unnecessary solder cannot be raised sufficiently. On the contrary, if the heating time is long, the wetting effect is lowered because the heat-sensitive flux is high heat.

  Also, in the case of soldering parts of two adjacent leads, the molten solder adhering between the two leads works by surface tension to reduce the surface area and is pulled to the larger capacity and has a small surface area. Try to be spherical. Therefore, when the parallel direction of the two leads is parallel to the flow direction of the molten solder, the molten solder adhering between the two leads is still immersed in the flow solder and a large amount of molten solder adheres. Since it is pulled by the solder of the upstream lead, it is difficult to form a bridge. However, when the two juxtaposed directions are perpendicular to the flow direction of the molten solder, the molten solder drawn by the surface tension is not on the outside (upstream side), and therefore gathers at the center of the two leads. Bridging is likely to occur. If a bridge or wiggle occurs, it causes a serious failure such as a short circuit or a spark.

  Therefore, a method for suppressing bridges and icicles has been considered. For example, Patent Document 2 (Japanese Patent Application Laid-Open No. 8-288634) includes a configuration that allows the height of the weir flowing out from the secondary jet solder tank to be adjusted, so that the printed circuit board is in contact with the molten solder. It is described that the time and flow velocity are adjusted to optimum values to reduce the occurrence of bridges and icicles. It also describes that the separation angle at the peelback point is increased to suppress the occurrence of bridges and wiggles. Further, in Patent Document 3 (Japanese Patent Laid-Open No. 11-54902), by providing a venturi passage for sucking out the solder flowing out from the secondary jet solder tank, the flow velocity of the molten solder detaching from the printed circuit board is rapidly increased. It is described to reduce the occurrence of bridging.

JP 2000-22323 A JP-A-8-288634 JP-A-11-54902

  However, although there are techniques as described in Patent Document 2 and Patent Document 3, in actual production, it has not been possible to eliminate the occurrence of bridges and icicles.

Furthermore, there was a social situation in which bridges and icicles are likely to occur. From July 1, 2006, the use of lead as a hazardous substance in electronic and electrical equipment was prohibited in principle in the European Union. In principle, China and Korea prohibit the use of lead in electronic and electrical equipment, and voluntary regulations are imposed in Japan and the United States. For conventional eutectic solder containing 63% tin and 37% lead, including lead, the melting point is 183 ° C, the desired angle of separation from the printed circuit board is 5 to 5.5 degrees, and the allowable contact between the printed circuit board and the molten solder The time is 2 to 5 seconds. In contrast, lead-free, 96.5% tin (Sn) is silver (Ag) is 3.0%, the lead-free solder of copper (Cu) is 0.5%, a melting point of 220 ° C. ~ 230 degreeC, the separation angle with a desirable printed circuit board is 4.5 to 5 degrees, and the allowable contact time of a printed circuit board and molten solder is 3 to 6 seconds. Thus, lead-free solder that does not contain lead has a high melting point.

For this reason, in order to raise the temperature of the solder adhered in the primary jet soldering process, it is necessary to lengthen the contact time with the molten solder, so the separation angle must be reduced. However, there is a problem that if the separation angle is reduced, bridges and wiggles are more likely to occur. In other words, the use of lead was banned, which increased the occurrence of bridges and icicles. Under such circumstances, the occurrence rate of bridges in the jet-type soldering apparatus is at most 5000 ppm to 10,000 ppm.

In addition, according to the inventor's verification, it has been found that the time during which the molten solder is detached from the printed circuit board in the secondary jet soldering process is about 2 seconds apart between the early and late areas in the same printed circuit board. Yes. Since the allowable contact time is 3 to 6 seconds, a gap of about 2 seconds within this time will cause uneven soldering quality, and early separation will result in insufficient temperature rise and bridging of bridges and tiles. There is a problem that it is a major factor of occurrence.

  As shown in FIG. 4B, the cause of this separation is the difference in land shape (R1, R2, R3), the difference in lead shape (L1, L2), and the arrangement of adjacent leads in the flow direction of molten solder. This is probably due to the difference in direction (A1, A2) and the like, as to the shape of the scattered solder and the manner in which the surface tension is applied when the molten solder is detached from the printed circuit board P. In other words, since the specific gravity of the solder is large, the specific gravity of the solder quickly overcomes the surface tension depending on the location, so that early solder separation occurs.

  Therefore, the present invention makes the contact time in the secondary jet soldering process within an allowable range, shortens the time interval for the molten solder to separate from the printed circuit board, and achieves uniform soldering quality and prevents early separation. An object of the present invention is to provide a jet-type soldering device that raises the temperature sufficiently and increases the separation angle to suppress the generation of bridges and wiggles.

In order to achieve the above object, a jet soldering apparatus of the present invention includes a primary jet nozzle and a secondary jet nozzle, and in the primary jet soldering process, molten solder is extracted from the primary jet nozzle. A jet-type soldering apparatus for performing soldering by performing jetting and soldering, and in the secondary jet soldering process, performing soldering by melting solder that jets molten solder from the secondary jet nozzle and flows on the plate, A weir for securing the molten solder ejected from the secondary jet nozzle is provided on the plate in the secondary jet solder process, and between the secondary jet nozzle and the weir. In the range where the molten solder in the secondary jet soldering process is in contact with the printed circuit board, the solder detachment control for directing the flow of the molten solder toward the printed circuit board side is performed. Rods are provided on the said plate extending in said molten solder in the flow direction and perpendicular direction, the desoldering control rod, characterized in that the possible positional adjustment in molten solder flow direction .

  By providing the solder detachment control rod on the plate, the molten solder is lifted to the printed circuit board side, and it is possible to prevent the molten solder, which has been released earlier because the specific gravity of the solder has overcome the surface tension, from being released earlier. The variation in the separation time is reduced, and the soldering quality is uniform with little variation in the heating time. Furthermore, it is possible to suppress bridges and icicles that are caused by insufficient temperature rise due to early separation. Also, at the end of the solder removal control rod in the flow direction, the molten solder pressed in the direction of the printed circuit board by the solder removal control rod falls from the height of the solder removal control rod, so that a large separation angle is obtained. . When the separation angle increases, the generation of bridges and wiggles can be suppressed.

  In the jet-type soldering device of the present invention, it is preferable that the position of the solder removal control rod can be adjusted in the flow direction of the molten solder. For example, the inclination angle of the plate may be changed depending on the length of the lead of the component to be soldered. When the tilt angle of the plate changes, the region where the molten solder is detached changes. Also, the region where the molten solder is detached and the appropriate heating time change depending on environmental changes such as temperature and humidity. Accordingly, by making it possible to adjust the position of the solder removal control rod in the flow direction of the molten solder, it is possible to cope with changes in the inclination angle of the plate, environmental changes, and the like.

Further, the solder separation control method in the jet type soldering apparatus of the present invention includes a primary jet nozzle and a secondary jet nozzle, and in the primary jet soldering process, molten solder is discharged from the primary jet nozzle. performs soldering by spouting, definitive desoldering the nozzle-type soldering apparatus for performing soldering by molten solder flowing over a plate and ejecting the molten solder from the secondary jet nozzle in the secondary jet flow soldering process In the control method, a weir for securing the molten solder ejected from the secondary jet nozzle is provided on the plate in the secondary jet solder process, and the secondary jet nozzle in the range where the molten solder is in contact with the printed circuit board of the secondary jet flow soldering step in until the dam, to the plate, the molten Sunda with extending in a flow direction perpendicular to the direction of, wherein the molten solder flow direction in a position adjustable desoldering control rod installed, to direct the flow of the molten solder on the printed circuit board side And

  Although the jet type soldering device is very expensive, it is possible to obtain a uniform soldering quality as well as a bridge and solder by attaching a solder removal control rod that directs the flow of molten solder to the printed circuit board side to the existing jet type soldering device. The effect of suppressing the occurrence of icicles can be obtained with a low investment.

FIG. 1A is a diagram of a jet-type soldering apparatus showing the configuration of the embodiment, and FIG. 1B is a diagram showing a secondary melting soldering operation of the embodiment. FIG. 2A is a schematic diagram of the timing at which the molten solder is detached from the printed board in the embodiment, and FIG. 2B is a schematic diagram of the timing at which the conventional molten solder is detached from the printed board. FIG. 3A is a graph showing the pressure of the embodiment that the printed circuit board receives by the molten solder, and FIG. 3B is a graph that shows the conventional pressure that the printed circuit board receives by the molten solder. FIG. 4A is a diagram of a jet-type soldering apparatus showing a conventional configuration, and FIG. 4B is a diagram showing factors on the printed circuit board side where the separation timing of the molten solder varies.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the embodiments and drawings. However, the embodiments shown below are not intended to limit the present invention to those described herein, and The invention can be equally applied to various modifications without departing from the technical idea shown in the claims. In addition, in each drawing used for the description in this specification, in order to make each member a size that can be recognized on the drawing, each member is displayed with a different scale, and is not necessarily actual. It is not displayed in proportion to the dimensions.

  The structure of the jet type soldering apparatus of embodiment of this invention is demonstrated using FIG. 1A. The process of the jet type soldering apparatus 1 of this embodiment is the flux application | coating process S1 which has the flux application | coating machine 11 in that order, produces | generates the bubble 12 containing a flux, and adheres this to the surface by the side of the pattern of the printed circuit board P, Heating process S2 that raises the printed circuit board P to an appropriate temperature with the heater 21, the strong wave blown up with the primary jet nozzle 31, and details such as soldering and through-holes to chip parts A primary jet solder process S3 for injecting molten solder, a secondary jet solder process S4 having a secondary jet nozzle 41, and removing unnecessary solder by remelting bridges and tsura with a gentle jet, fan And a cooling step S5 for lowering the temperature of the printed circuit board P. And the printed circuit board P is conveyed from the flux application | coating process S1 to the cooling process S5 with the conveying machine which is not shown in figure.

  As shown in FIGS. 1A and 1B, a plate 44 is inclined downward on the downstream side of the secondary jet nozzle 41 in the cooling step S <b> 5 direction. The molten solder S ejected from the secondary jet nozzle 41 flows along the plate 44. A weir (back plate) 42 for securing a certain amount of molten solder S on the plate 44 is provided on the downstream end side of the plate 44. Then, the molten solder S is refluxed by dropping the weir 42. A sufficient distance by the plate 44 is secured between the secondary jet nozzle 41 and the weir 42. Therefore, the contact time between the printed circuit board P and the molten solder S can be secured by adjusting the separation position between the printed circuit board P and the molten solder S. Further, the height of the weir 42 can be changed as in Patent Document 2. For this reason, the rough time when the printed circuit board P is in contact with the molten solder S can be adjusted. In the jet-type soldering apparatus 1, the molten solder S that flows over the weir 42 does not contact the printed circuit board P at the position of the weir 42.

  A solder removal control rod 43 is installed on the plate 44 between the secondary jet nozzle 41 and the weir 42, and the solder removal control rod 43 is fixed in an area where the molten solder S contacts the printed circuit board P. ing. The solder detachment control rod 43 is formed of an elongated rod-shaped metal member having a square cross section (for example, a square with a side of 6 mm). Further, the plate 44 is disposed so as to extend from the end of the plate 44 in a direction perpendicular to the direction in which the molten solder S flows (see FIG. 2). Note that the end portion of the solder removal control rod 43 is fixed by a fixing means capable of finely adjusting the position of the solder removal control rod 43 in a direction parallel to the flow of the molten solder S. Further, the fixing means for fixing the solder detachment control rod 43 may be provided either by the solder detachment control rod 43 itself or by the jet-type soldering apparatus 1 or by both. It doesn't matter.

  Next, the effect that the jet flow type soldering apparatus 1 is provided with the solder detachment control rod 43 will be described. First, as shown in FIG. 1A, when the printed circuit board P has not reached the secondary jet soldering step S4, the molten solder S flowing from the secondary jet nozzle 41 onto the plate 44 flows over the solder removal control rod 43. . As a result, the molten solder S undulates and protrudes above the solder removal control rod 43 (protruding portion U). In FIG. 1A, the protruding molten solder S is emphasized. Therefore, even when the surface of the molten solder S is observed in the actual jet-type soldering apparatus 1, the specific gravity of the solder is very large. Therefore, such clear protrusion of the molten solder S cannot always be observed.

  Next, as shown in FIG. 1B, when the printed circuit board P is conveyed on the solder removal control rod 43, the path of the molten solder S is directed toward the printed circuit board P by the solder removal control rod 43. P is subjected to pressure upward by the molten solder S.

  Here, a description will be given with reference to FIG. 2 in order to make it easier to imagine the effect of the solder removal control rod 43. FIG. 2 is a schematic diagram comparing the timing at which the molten solder S is detached from the printed circuit board P with the prior art. Specifically, FIG. 2A is a schematic diagram showing timing in the present embodiment, and FIG. 2B is a schematic diagram showing conventional timing.

  In the conventional case where the solder removal control rod 43 is not installed on the plate 44 shown in FIG. 2B, the time for the molten solder S to separate from the printed circuit board P differs as described above. It does not fall in a horizontal line at the ideal drop position. Therefore, a large variation has occurred in the drop position L where the molten solder S is detached from the printed circuit board P.

  On the other hand, in the present embodiment shown in FIG. 2A, the position of the solder removal control rod 43 so that the undulation protrusion U of the molten solder S by the solder removal control rod 43 is formed at the position corresponding to the conventional variation region F ′. Are adjusted and arranged on the plate 44. As a result, the melted solder S that has been separated from the printed circuit board P on the upstream side earlier is delayed until the protruding portion U passes by the swelled protruding portion U, and is delayed on the downstream side. Then, all of the molten solder S that has been separated from the printed circuit board P is released at once. That is, as shown in FIG. 2B, the conventional drop position L varies widely as in the area F ′. However, by arranging the solder removal control rod 43, the drop position L is in the area F as shown in FIG. In this way, the solder detachment control rods 43 are aligned in a horizontal line on the downstream side.

  As described above, since the variation in the time during which the molten solder S contacts the printed circuit board P is eliminated, the temperature rise of the solder adhered to the printed circuit board P in the primary jet solder process S3 is uniform in the secondary jet solder process S4. Thus, there is an effect that the soldering quality becomes uniform. In addition, bridges and icicles caused by insufficient temperature rise can be eliminated.

  Here, the comparison between FIG. 3A of the present embodiment and the conventional FIG. 3B is a graph in which the inventor measured the pressure, the vertical axis is the upward pressure that the printed circuit board P receives by the molten solder S, and the horizontal axis is the flow. The position of the direction.

  In addition, the peak shown on the left side of FIG. 3A and FIG. 3B is the pressure which the printed circuit board P receives by the molten solder jetted from the primary jet nozzle 31 in the primary jet solder process S3. The peak shown on the right side of FIGS. 3A and 3B is the pressure received by the printed circuit board P by the molten solder jetted from the secondary jet nozzle 41 in the secondary jet solder process S4. As can be seen from the figure, the primary jet solder process S3 applies a stronger pressure to the printed circuit board P in a shorter time than the secondary jet solder process S4.

  Here, a region G circled in FIG. 3A is the pressure changed by the solder removal control rod 43. In the conventional configuration of FIG. 3B, the pressure received by the printed circuit board P is only gradually reduced, but immediately before the molten solder S is detached from the printed circuit board P by installing the solder removal control rod 43. An upward pressure is applied to the printed circuit board P.

  Actually, the pressure received by the printed circuit board P becomes zero when the printed circuit board P and the molten solder S are separated from each other. However, due to the structure of the measuring instrument that measures the pressure in this embodiment, FIG. 3A and FIG. The position where the pressure received by the printed circuit board P is 0 is not the position where the printed circuit board P and the molten solder S are separated. Therefore, for example, since the printed circuit board P and the molten solder S are actually separated after the region G in FIG. 3A, the printed circuit board P is not subjected to pressure, but after the region G due to the structure of the measuring instrument. The pressure gradually decreases.

  Further, as shown in FIG. 1B, since the molten solder S flows down from the height of the solder removal control rod 43, the molten solder S is removed from the printed circuit board P in a state where the printed circuit board P is conveyed to above the solder removal control rod 43. The separation angle θ1 is larger than the conventional separation angle θ2 without the solder removal control rod 43. Therefore, generation | occurrence | production of a bridge | bridging and wiggle can be suppressed.

According to the verification by the present inventor, the occurrence rate of the bridge in the jet-type soldering device is usually 5000 ppm to 10000 ppm at best, but by providing the solder removal control rod 43, the occurrence rate of the bridge Decreased significantly from 1/5 to 1/10.

  By adjusting the position of the solder removal control rod 43 on the plate 44, the time during which the printed circuit board P is in contact with the molten solder S (heating time of the printed circuit board P) can be adjusted. This eliminates this adjustment at the weir 42.

  In this way, the solder detachment control rod 43 that has uniform soldering quality and can suppress the occurrence of bridges and wiggles can be easily added to the existing jet-type soldering device 1. As a result, it is possible to reduce the capital investment by adding only the solder removal control rod 43 without newly purchasing an expensive jet-type soldering device or replacing the nozzle part including the plate 44 through which the solder S flows. Uniform soldering quality and the effect of suppressing the occurrence of bridges and icicles can be obtained.

  On the other hand, if it is a manufacturer of a jet type soldering apparatus, the solder removal control rod 43 integrated with the plate 44 through which the molten solder S in the second jet soldering step S4 flows can also be provided. At this time, the length of the plate 44 can be adjusted to adjust the position of the solder removal control rod 43. Further, the solder removal control rod 43 may be formed on the plate 44 by integral molding.

  In addition, although the solder detachment control rod 43 of the above-described embodiment has a quadrangular cross section, the present invention is not limited to the quadrilateral, and any shape that directs the flow of the molten solder S toward the printed circuit board P may be used. For example, even if the cross section is a trapezoid or a semicircular arc, the effect of the present invention is obtained. However, according to the inventor's verification, it is known that the area of the top of the solder removal control rod 43 is preferably wider, and the cross section of the solder removal control rod 43 is more square than a trapezoid or semicircular arc. preferable.

1: Jet type soldering device 31: Primary jet nozzle 41: Secondary jet nozzle 43: Solder detachment control rod 44: Plate F: Area L: Dropping position P: Printed circuit board S: Molten solder S1: Flux application process S2: Heating process S3: Primary jet solder process S4: Secondary jet solder process S5: Cooling process

Claims (2)

A primary jet nozzle and a secondary jet nozzle;
In the primary jet solder process, the molten solder is ejected from the primary jet nozzle to perform soldering,
In the secondary jet soldering process, a jet type soldering apparatus for performing soldering by melting solder that jets molten solder from the secondary jet nozzle and flows on the plate,
A weir for securing the molten solder ejected from the secondary jet nozzle is provided on the plate in the secondary jet solder process, and between the secondary jet nozzle and the weir. In a range where the molten solder in the secondary jet soldering process is in contact with the printed circuit board, a solder detachment control rod for directing the flow of the molten solder toward the printed circuit board extends in a direction perpendicular to the flow direction of the molten solder. Provided on the plate ,
The jet soldering apparatus according to claim 1, wherein the position of the solder removal control rod can be adjusted in the flow direction of the molten solder . A primary jet nozzle and a secondary jet nozzle;
In the primary jet solder process, the molten solder is ejected from the primary jet nozzle to perform soldering,
In the secondary jet soldering process a definitive desoldering control method jet type soldering apparatus for performing soldering by molten solder flowing over a plate and ejecting the molten solder from the secondary jet nozzle,
A weir for securing the molten solder ejected from the secondary jet nozzle is provided on the plate in the secondary jet solder process, and between the secondary jet nozzle and the weir. In the range where the molten solder of the secondary jet solder process is in contact with the printed circuit board,
On the plate, a solder detachment control rod extending in a direction perpendicular to the flow direction of the molten solder and adjustable in the flow direction of the molten solder is installed, and the flow of the molten solder is directed to the printed circuit board side. A solder detachment control method in a jet-type soldering apparatus, characterized in that the solder detachment is directed .

Images