JP2009043956A - Flow soldering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow soldering device that simultaneously suppresses a temperature drop by shortening an interval between a primary jet stream and a secondary jet stream and also prevents deterioration in soldering quality due to dross for a flow soldering method of mounting an electronic component on a substrate using a lead-free solder material. <P>SOLUTION: The flow soldering device has a solder tank to contain a molten solder material, a primary jet stream nozzle to jet the primary jet stream of the molten solder material, a secondary jet stream nozzle to jet the secondary jet stream of the molten solder material, and a partition disposed between the primary jet stream nozzle and the secondary jet stream nozzle, and can obtain excellent soldering quality by suppressing upward creeping of dross on a surface of a jet stream and temperature dropping of the substrate after the primary jet stream. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flow soldering apparatus for mounting an electronic component or the like on a substrate using a solder material.

  2. Description of the Related Art Conventionally, in manufacturing an electronic circuit board, as one method for joining an electronic component or the like to a board, a flow is used in which a molten solder material is jetted from below the electronic circuit board and soldered between the electronic circuit board and the electronic component. Soldering methods are known. This flow soldering method generally includes a flux application process for applying flux to a substrate, a preheating process for preheating the substrate, and a solder material that supplies the solder material to the substrate by bringing the substrate into contact with a jet of solder material. Including a supplying step. Hereinafter, a conventional general flow soldering method will be described with reference to the drawings. FIG. 7 is a structural diagram of a conventional flow soldering apparatus.

  First, flux is supplied to an electronic circuit board such as a printed circuit board in which electronic parts such as insertion parts are appropriately arranged at predetermined positions using a flux supply means (not shown), and the flux is applied to the lower surface of the board. To do. The flux usually includes an active component such as rosin (resin component) and a solvent such as isopropyl alcohol, and the flux application process for applying such flux to the substrate is performed by the land formed on the substrate (that is, supplied by the solder material). This is performed for the purpose of removing the oxide film (natural oxide film) inevitably formed on the portion) and improving the wetting and spreading of the solder material on the land surface. As the flux supply means, a spray fluxer for spraying a mist-like flux onto the substrate, a foaming fluxer for bringing the foam-like flux into contact with the substrate, or the like can be used. Such a flux supplying means may be configured separately from the flow soldering device 13 or may be configured integrally with the flow soldering device 13.

  The substrate 3 coated with the flux as described above is supplied from the inlet 11 to the flow soldering apparatus 13 of FIG. The substrate 3 is mechanically transported at a constant speed in the direction of the arrow 10 inside the apparatus 13 (along the transport line indicated by a dotted line in FIG. 7). The substrate 3 conveyed inside the apparatus 13 from the inlet 11 to the outlet 12 is first heated by a preheater 8 positioned below the substrate 3 such as a far infrared heater. The preheating step by heating increases the temperature of the substrate body by heating the substrate 3 in advance and reducing the temperature gradient in the vertical direction of the substrate 3 prior to the supply of the solder material 2 to the substrate 3. In order to vaporize unnecessary solvent components in the flux applied to the substrate 3 by the flux application step, and the wetting time (the time required from when the solder material contacts the workpiece (land in this case) to when wetting begins. ).

  Then, the board | substrate 3 is conveyed above the solder material supply means 7 containing the solder tank 1 etc. in which the solder material 2 previously fuse | melted by heating was contained. Then, the solder material 2 comes into contact with the primary jet of the solder material 2 supplied from the primary jet nozzle 4 and the secondary jet of the solder material 2 supplied from the secondary jet nozzle 5 to the lower surface side of the substrate 3. It is supplied to the substrate 3. At this time, the solder material 2 includes an inner wall of a through hole (not shown) formed in the substrate 3 and leads (not shown) of through-hole insertion parts inserted into the through hole from the upper surface side of the substrate 3. The annular space between the two is wetted from the lower surface side of the substrate 3 by capillary action. Thereafter, the solder material supplied to and adhered to the substrate 3 is solidified due to a decrease in temperature to form a joint made of the solder material, a so-called “fillet”.

  In this solder material supply step (or flow soldering step), the solder material 2 is supplied from the primary jet nozzle 4 to the substrate 3. FIG. 8 shows a structural diagram of a conventional solder material supply means. As shown in FIG. 8, the solder material supply means 7 includes a primary jet nozzle 4 and a secondary jet nozzle 5 disposed behind the primary jet nozzle 4. The secondary jet nozzles 5 are arranged at intervals of about 50 mm so that the jets are not mixed and the soldering quality is not deteriorated. The primary jet nozzle 4 includes a plurality of protrusions 14 at the tip, and the solder material 2 is supplied from the protrusions 14. The solder material supplied from the protrusions 14 is in a turbulent state when the substrate passes over it, and has a function of making sure that the solder material 2 comes into contact with the inside of the through hole and the substrate surface land. If this is insufficient, the solder material 2 is not sufficiently wetted and spread in the through holes and lands, and the supply of the solder material becomes insufficient, so that problems such as so-called “red eyes” occur. However, since the primary jet is in a turbulent state, the solder material remains in the area covered with the solder resist, or the solder material remains in the land portion in a distorted shape. Generate a situation. Therefore, it is necessary to remove the solder material adhering to the area covered with the solder resist by the secondary jet of the flow close to the laminar flow state, and to adjust the shape of the fillet of the land portion. If this is insufficient, the solder material will remain and solidify between the lands, forming a so-called “bridge” (which is undesirable because this bridge will cause a short circuit in the electronic circuit), or forming a square protrusion. This is not desirable.

  In the solder material supplying process, the primary jet and the secondary jet having different properties are indispensable, and a good soldering state cannot be obtained by itself.

  The substrate 3 obtained in this way is then taken out from the outlet portion 12, thereby producing an electronic circuit board in which electronic components are soldered to the substrate 3 by a flow soldering method.

  In the electronic circuit board manufactured as described above, conventionally, an Sn—Pb solder material having Sn and Pb as main constituent components, in particular, an Sn—Pb eutectic solder material is generally used. However, since lead contained in the Sn—Pb solder material may cause environmental pollution due to inappropriate waste treatment, a solder material not containing lead, so-called “so-called“ “Lead-free solder materials” are mainly used on an industrial scale.

  Lead-free solder materials generally have a higher melting point than Sn—Pb solder materials. For example, the melting point of the Sn—Pb eutectic solder material is 183 ° C., whereas the Sn—Ag—Cu-based material that is a typical lead-free solder material has a temperature of about 227 ° C. Therefore, the solder tank 1 containing the solder material 2 is heated so that the temperature of the solder material is 235 to 245 ° C in the case of Sn-Pb solder material and 250 to 255 ° C in the case of lead-free solder material. Yes.

  When a lead-free solder material is used due to the difference in melting point temperature of the solder material 2, the molten solder material 2 supplied from the primary jet nozzle 4 and attached to the substrate 3 is supplied from the secondary jet nozzle 5. Until the new solder material 2 is supplied to the substrate 3, it is considered that the heat is deprived through the substrate 3 and by the surrounding atmosphere and is partially solidified. Such a phenomenon was not a problem when using a Sn—Pb solder material having a relatively low melting point. However, in the case of a lead-free solder material having a high melting point, the secondary phenomenon occurs after the substrate 3 leaves the primary jet. It is thought that it reacts sensitively to a slight temperature drop during contact with the jet and initiates solidification. Thus, it is necessary to melt again the solidified solder material 2 by the secondary jet between the time when the primary jet leaves and the time when the secondary jet comes into contact with the secondary jet. However, remelting by the secondary jet is not sufficient. And so-called “bridges” may occur.

  FIG. 9 shows a temperature curve of an electronic circuit board in conventional flow soldering. The horizontal axis represents the flow soldering process (process time), and the vertical axis represents the temperature of the electronic circuit board. The electronic circuit board is conveyed at a speed of about 1.5 m / min (25 mm / sec). The electronic circuit board is heated to 85 to 95 ° C. by preheating, receives the heat of the solder by the primary jet, and rises to 250 to 255 ° C. Thereafter, it takes about 2 seconds (the interval between the primary jet nozzle and the secondary jet nozzle is 50 mm) to reach the secondary jet, so the temperature drops to 170 ° C. and the solder of the primary jet solidifies. Thereafter, the secondary jet soldering is performed on the solidified primary jet solder.

  In order to improve the influence of the temperature drop of the substrate 3 as described above, a method of applying a cover 9 above the preheater 8 and above the solder material supply means 7 has been reported (for example, see Patent Document 1).

  The quality of soldering by inserting a component electrode into a through hole of a board on which an electronic component is mounted by the soldering method as described above will be described. FIG. 10 shows a photograph of a cross section of a through hole portion of an electronic component when the electronic component is mounted on a substrate using a conventional flow soldering apparatus. FIG. 10 is a cross-sectional view of the through hole 21, the electronic component lead 22 inserted into the through hole 21, and the solidified solder 23 supplied between the through hole 21 and the electronic component lead 22. The solder 23 has voids 24 generated by bubbles.

  When the electronic device is used, the temperature of the soldering part is repeatedly raised and lowered by turning the power on / off. If this void 24 is present in the solidified state of the solder, a crack called a crack occurs from the void 24 as a starting point. However, electrical continuity is lost, leading to failure of electronic equipment. Further, when the cracked circuit is a high-voltage part, when electrical continuity is lost and an open circuit state is established, arc discharge may be caused, causing ignition and smoke generation.

  The cause of the void 24 in the solidified solder 23 is due to the temperature drop until the secondary jet is reached after leaving the primary jet. The solder material once supplied to the upper portion of the through-hole 21 by the primary jet begins to solidify as soon as it leaves the primary jet. Next, when passing through the secondary jet, the solder material supplied by the primary jet starts to melt again, but when the temperature drop between the primary jet and the secondary jet is large, it passes through the secondary jet. At this time, the temperature up to remelting cannot be reached in the upper part of the through hole 21. Accordingly, the secondary jet solder material is supplied in a state where the solder material on the upper portion of the through hole 21 is solidified, that is, in a state where the upper portion of the through hole 21 is covered with the solidified solder material. When supplying the solder material by the primary jet and the secondary jet, ambient air is entrained in the solder jet. Therefore, if a secondary jet of solder is supplied in a state where the upper part of the through hole 21 is covered with a solidified solder material, the air present in the solder jet cannot escape from the upper part of the through hole 21 and the secondary jet. When the solder material cools and hardens after leaving the jet, it remains as a void.

  In order to suppress the generation of the void 24, the solder material on the upper portion of the through hole 21 from the time when the primary jet is left until the secondary jet comes into contact is prevented from solidifying. Although it is necessary to suppress the temperature drop so that the temperature does not fall below the melting point of the material, (1) increase the substrate temperature in the preheating step, (2) contact the primary jet and secondary jet with the substrate It is conceivable to increase the temperature of the substrate and raise the substrate temperature, (3) increase the solder temperature of the primary jet and the secondary jet, and (4) shorten the interval between the primary jet and the secondary jet. However, when considering the heat resistance of the electronic component mounted on the board 3, it is necessary to shorten not only the lead of the electronic component to be soldered but also the body part of the electronic component as much as possible to the high temperature, The means (1), (2), and (3) have a limit in suppressing the temperature drop, and the current high-performance electronic component reaches the limit.

  And when shortening the space | interval between the primary jet of (4) and a secondary jet, it is ultimately making it one, but as mentioned in the background art, a primary jet and a secondary jet Cannot be combined because they have different process properties. Also, when the primary and secondary jets are brought close to each other, the oxide of the solder material called “Dross”, which has a lower specific gravity than the solder material, stays in the intersection of the solder material that flows from the primary jet and the solder material that flows from the secondary jet. As a result, dross may flow back toward the top of the jet and adhere to the substrate, resulting in deterioration of soldering quality and poor soldering.

  Further, the backflow of the dross will be described in detail. In the conventional solder flow apparatus, since the interval between the primary jet and the secondary jet is wide, the solder material supplied from each jet is independently returned to the solder bath, Dross generated on the surface of each jet flows down to the solder bath without crossing. Although dross stays on the surface of the solder bath, since the solder material of the primary jet and the secondary jet is supplied from the inside of the solder bath, no dross is mixed in the jet. Further, since the solder material flowing down from the primary jet and the secondary jet flows into the solder bath in a state of being nearly vertical, the surface does not flow back toward the top of the jet against gravity and flow.

  However, when the primary jet and the secondary jet are brought close to each other, the jets are mixed with each other before flowing into the solder bath, and a dross rising phenomenon occurs. FIG. 11 is a schematic diagram illustrating the dross climbing phenomenon. In the portion where the primary jet and the secondary jet are mixed, the film state of the thin film-like dross 61 is destroyed and stays as a dross mass 62. Part of the retained dross mass 62 falls into the solder bath 1 from both sides in the vertical direction with respect to the drawing. As the dross mass 62 moves toward the top of the primary jet and the secondary jet, the angle of the jet becomes smaller with respect to the horizontal plane, and the unoxidized solder material 2 flows under the dross 61 and the dross on the surface. The film 61 becomes increasingly difficult to break. The speed of the dross 61 supplied from the top of the jet, the speed at which the dross film is destroyed at the intersection of the primary jet and the secondary jet, and the dross lump 62 is deposited as the dross lump 62 falls into the solder bath. If the speed of movement goes out of balance, the result is that the dross climbs to the top.

  From these things, the space | interval between a primary jet and a secondary jet cannot be shortened easily.

Further, a mechanical method has been devised as a method for discharging the accumulated dross (see, for example, Patent Document 2). However, when a device for discharging dross by a mechanical method is applied between the primary jet and the secondary jet, it is more difficult to physically reduce the interval between the primary jet and the secondary jet. The temperature drop of the solder material between the jet and the secondary jet cannot be suppressed.
JP 2002-111194 A JP 2002-176250 A

  The present invention solves the above-mentioned conventional problems, and in a flow soldering method for mounting an electronic component on a substrate using a lead-free solder material, the interval between the primary jet and the secondary jet is reduced to suppress the temperature drop. The present invention also provides a flow soldering apparatus for achieving both prevention of deterioration of soldering quality due to dross.

  In order to solve the above-described conventional problems, a flow soldering apparatus according to the present invention includes a solder bath for containing a molten solder material, a primary jet nozzle for primarily jetting the molten solder material, and a molten solder. A secondary jet nozzle for secondary jetting of material, and a partition wall disposed between the primary jet nozzle and the secondary jet nozzle, and soldering by shortening the interval between the primary jet nozzle and the secondary jet nozzle Do.

  With this configuration, the dross scooping generated on the surface of each jet is suppressed, the temperature drop of the substrate after the primary jet is suppressed, and 2 before the solder material in the primary jet solidifies during the secondary jet. Soldering by the next jet can be performed.

  According to the flow soldering apparatus of the present invention, the temperature drop of the substrate between the primary jet and the secondary jet is suppressed, and the solder material in the through hole is solidified between the primary jet and the secondary jet. It is possible to suppress the generation of voids in the through hole, and to realize good quality soldering without being affected by dross.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a structural diagram of the flow soldering apparatus according to the first embodiment of the present invention. As shown in FIG. 1, the flow soldering apparatus 100 according to the first embodiment of the present invention includes a solder material supply unit 120 that supplies a solder material 110 and a transport unit 140 that transports an electronic circuit board 130. Yes.

  The conveying means 140 includes a conveyor 141 that conveys the electronic circuit board 130 to the solder supply means 120, a conveyor inlet 142, a conveyor outlet 143, a pre-heater 144 provided in the lower part of the conveyor 141 before the material supply means 120, It comprises a preheater 144 and a heat insulation cover 145 for keeping the temperature of the electronic circuit board 130 conveyed on the conveyor 141 of the solder material supply means 120.

  The solder material supply means will be described in detail. FIG. 2 is a structural diagram of the solder supply means in Embodiment 1 of the present invention. As shown in FIG. 2, the solder material supply means 120 includes a primary jet nozzle 121 that causes the molten solder material 110 to perform a primary jet, a secondary jet nozzle 122 that causes a secondary jet, and primary jet nozzles 121 and 2. It is comprised from the partition 123 arrange | positioned between the next jet nozzles 122, and the solder tank 124 containing the solder material 110 fuse | melted by heating beforehand.

  The solder material 110 is a lead-free solder material, for example, a Sn—Ag—Cu-based material having a melting point of about 227 ° C. Therefore, the solder bath 124 containing the solder material 110 is heated to 250 to 255 ° C.

  The primary jet nozzle 121 and the secondary jet nozzle 122 have substantially the same specifications as those used in the past, but the distance between the primary jet nozzle 121 and the secondary jet nozzle 122 is reduced from about 50 mm to about 30 mm or less. It is shortened. By shortening the interval between the primary jet nozzle 121 and the secondary jet nozzle 122, the temperature of the electronic circuit board 130 after the primary jet is brought into contact with the secondary jet, that is, the solder is used in the primary jet. Since the applied solder material 110 contacts the secondary jet before it completely solidifies, bubbles during flow soldering are released from above the through holes of the electronic circuit board 130.

  The arrangement of the partition wall 123 will be described with reference to FIG. The horizontal arrangement in FIG. 2 is arranged perpendicular to the position where the primary jet and the secondary jet are mixed when there is no partition wall 123. 2 is arranged such that the line connecting the tip of the primary jet nozzle 121 and the tip of the secondary jet nozzle 122 is the tip of the partition wall 123. If it is arranged at a position above the line connecting the tip of the primary jet nozzle 121 and the tip of the secondary jet nozzle 122, it hits the lead wire of the electronic component of the electronic circuit board 130, and the electronic circuit board 130 Transport will be hindered. The arrangement position of the depth direction of FIG. 2 is arrange | positioned in the position which can cover the depth of the primary jet nozzle 121 and the secondary jet nozzle 122 so that a primary jet and a secondary jet may not mix.

  The size of the partition wall 123 will be described with reference to FIG. FIG. 3 is a configuration diagram of the partition walls in the first embodiment of the present invention. In FIG. 3, the vertical direction is the height of the partition wall 123, the horizontal direction is the thickness of the partition wall 123, and the depth direction is the width of the partition wall 123.

  The height of the partition wall 123 is 5 to 10 mm above the surface of the melted solder material 110 contained in the solder bath 124 and below the surface of the melted solder material 110, that is, the melted solder material 110. 10 mm or more is required on the inner side. The upper height is a height necessary for preventing the solder material 110 from getting over the partition wall 123 even when the solder material 110 jetted from the primary jet nozzle 121 and the secondary jet flow 122 collides with the partition wall 123. Further, the lower height causes the solder material 110 jetted from the primary jet nozzle 121 and the secondary jet 122 to collide with the partition wall 123 so that the solder material 110 enters the solder bath 124. Is the height required for If the primary jet and the secondary jet collide directly, the jet energy cancels out due to the collision and the solder material 110 becomes difficult to enter the solder bath 124. Moreover, even if the lower height is 30 mm or more, the effect of canceling the energy of the jet does not change. Therefore, considering the material cost, the lower height is suitably 10 to 30 mm. That is, the total height of the partition wall 123 is suitably 15 to 40 mm.

  The width of the partition wall 123 is suitably 5 to 20 mm. Since the lower part of the partition wall 123 is in the solder material 120 heated to 250 ° C., the partition wall 123 is heated to 250 ° C. A thickness of 5 mm or more is necessary to prevent thermal deformation by heat at 250 ° C. Moreover, since the space | interval of the primary jet nozzle 121 and the secondary jet nozzle 122 is 30 mm or less, if the thickness of the partition 123 is large, a solder material will be made to flow backward to a primary jet nozzle or a secondary jet. Therefore, the width of the partition wall 123 is suitably 5 to 20 mm. In particular, the width of the partition wall 123 is optimally about 10 mm.

  The width of the partition wall 123 is suitably 5 to 20 mm. Since the lower part of the partition wall 123 is in the solder material 120 heated to 250 ° C., the partition wall 123 is heated to 250 ° C. A thickness of 5 mm or more is necessary to prevent thermal deformation by heat at 250 ° C. Moreover, since the space | interval of the primary jet nozzle 121 and the secondary jet nozzle 122 is 30 mm or less, if the thickness of the partition 123 is large, a solder material will be made to flow backward to a primary jet nozzle or a secondary jet. Therefore, the width of the partition wall 123 is suitably 5 to 20 mm. In particular, the width of the partition wall 123 is optimally about 10 mm.

  The width of the partition wall 123 is desirably 250 to 400 mm, which is equivalent to the width of the primary jet nozzle and the secondary jet nozzle.

  The partition wall 123 is made of titanium or stainless steel. This is because the melted solder material 110 collides with jet energy, so that the corrosion resistance to the solder is strong and the solder does not solidify when it cools, so that the solder wettability needs to be low. In particular, since titanium is expensive, austenitic stainless steel SUS304 and ferritic stainless steel SUS316 are desirable. In stainless steel, SUS316 is good with little erosion by solder. Furthermore, if the surface of stainless steel is nitrogenated to produce chromium nitride (CrN), the wettability of the solder can be further reduced.

  The partition wall 123 is fixed to the primary jet nozzle 121 or the secondary jet nozzle 122 with a screw or the like through a spacer so as to maintain a certain distance, and from the primary jet nozzle 121 and the secondary jet nozzle 122. The supplied solder material 110 has a structure capable of returning to the solder tank 124 through the space between the partition wall 123 and the primary jet nozzle 121 and the secondary jet nozzle 122. FIG. 4 is a schematic view showing an effect of suppressing the dross rising phenomenon by the partition wall in the first embodiment of the present invention.

  By applying the partition wall 123, drooping of the dross is suppressed, and the interval between the primary jet and the secondary jet can be reduced to 30 mm or less, and the temperature drop of the substrate between the primary jet and the secondary jet can be reduced. It can be 40 degrees C or less. In this specification, “the interval between the primary jet and the secondary jet” means that the substrate that is in contact with the primary jet is separated from the primary jet and comes into contact with the secondary jet. This is the interval.

  FIG. 5 shows a temperature curve of the electronic circuit board in flow soldering according to Embodiment 1 of the present invention. The horizontal axis represents the flow soldering process (process time), and the vertical axis represents the temperature of the electronic circuit board. The electronic circuit board is conveyed at a speed of about 1.5 m / min (25 mm / sec). The electronic circuit board is heated to 85 to 95 ° C. by preheating, receives the heat of the solder by the primary jet, and rises to 250 to 255 ° C. Thereafter, it takes about 1.2 seconds (the interval between the primary jet nozzle and the secondary jet nozzle is 30 mm) until the secondary jet is reached, so the temperature drops to 210 ° C. However, since it does not drop to 170 ° C. as in conventional flow soldering, the primary jet solder is not completely solidified. Thereafter, soldering of the secondary jet is performed on the solder of the primary jet that has not solidified.

  As a result, when the electronic circuit board 130 passes through the secondary jet, the solder material inside the through-hole supplied by the primary jet is sufficiently remelted, and the air present in the jet escapes from the top of the through-hole, Good soldering quality in which no void exists in the through hole can be obtained. FIG. 6 shows a photograph of the cross-section of the through hole portion of the electronic component when the electronic component is mounted on the substrate in the first embodiment of the present invention. FIG. 6 is a cross-sectional view of the through hole 221, the electronic component lead 222 inserted into the through hole 221, and the solidified solder 223 supplied between the through hole 221 and the electronic component lead 222. In the solder 223, voids generated by bubbles in the conventional flow soldering method do not exist.

  According to such a configuration, by arranging the partition wall between the primary jet nozzle and the secondary jet nozzle, the solder material dissolved in the solder bath can be reduced even if the interval between the primary jet nozzle and the secondary jet nozzle is shortened. The dross generated on the surface is prevented from crawling up to the primary jet or the secondary jet, and the solder of the secondary jet is solidified before the solder by the primary jet soldered to the electric circuit board is solidified. And good soldering without voids can be performed.

  In the present embodiment, the solder material 110 is Sn—Ag—Cu-based material, but other lead-free solder or lead solder may be used. In the case of lead solder, even better soldering quality can be obtained while the temperature of the solder bath remains at 235 to 245 ° C.

  In this embodiment, the heat insulation cover 145 is provided, but the heat insulation cover may not be provided. It is because it becomes possible to suppress the temperature fall of the board | substrate between a primary jet and a secondary jet. By removing the heat insulation cover of the flow soldering apparatus, it is possible to mount a high-level electronic component such as a flyback transformer on the substrate.

  In the present embodiment, the solder material 110 is Sn—Ag—Cu-based material, but other lead-free solder or lead solder may be used. In the case of lead solder, even better soldering quality can be obtained while the temperature of the solder bath remains at 235 to 245 ° C.

  In the present embodiment, the partition 123 is disposed at a position where the primary jet and the secondary jet are mixed when there is no partition 123, but may be close to the primary jet within 5 mm. Since the flow rate of the primary jet solder is smaller than that of the secondary jet, it is more preferable to make the secondary jet solder flow easily. Even if the primary jet solder is blocked and the dross rises slightly, the secondary jet acts to drop the dross during the primary jet, so that the solder quality can be kept good.

  In the present embodiment, the partition wall 123 is disposed vertically, but may be disposed in parallel to the two o'clock jet. Since the flow rate of the primary jet solder is smaller than that of the secondary jet, it is more preferable to make the secondary jet solder flow easily. Even if the primary jet solder is blocked and the dross rises slightly, the secondary jet acts to drop the dross during the primary jet, so that the solder quality can be kept good.

  In the present embodiment, the partition wall 123 is a plate material having a constant thickness as shown in FIG. 3, but may be an inverted triangle. By making the partition into an inverted triangle shape so that the partition is parallel to the primary jet and the secondary jet, the solder of the primary jet and the secondary jet can flow more easily.

  The flow soldering apparatus according to the present invention can remarkably suppress the temperature drop of the substrate between the primary jet and the secondary jet, and the temperature of the substrate between the primary jet and the secondary jet. This is an effective means in a soldering apparatus using a lead-free solder material that is easily affected by a decrease and generally has a melting point of 200 ° C. or higher.

Structure diagram of flow soldering apparatus in Embodiment 1 of the present invention Configuration diagram of solder material supply means in Embodiment 1 of the present invention Configuration diagram of partition walls in Embodiment 1 of the present invention The schematic diagram which shows the effect which suppresses the dripping phenomenon of dross by the partition in Embodiment 1 of this invention The figure of the temperature curve of the electronic circuit board in the flow soldering in Embodiment 1 of this invention The figure of the cross-sectional photograph of the through-hole part of an electronic component at the time of mounting an electronic component on a board | substrate in Embodiment 1 of this invention Structure diagram of conventional flow soldering equipment Structure diagram of conventional solder material supply means Figure of temperature curve of electronic circuit board in conventional flow soldering Figure of cross-sectional photograph of through hole part of electronic component when electronic component is mounted on substrate using conventional flow soldering equipment Schematic showing the dross climbing phenomenon

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Flow soldering apparatus 110 Solder material 120 Material supply means 121 Primary jet nozzle 122 Secondary jet nozzle 123 Bulkhead 124 Solder tank 130 Electronic circuit board 140 Conveyance means 141 Conveyor 142 Conveyor inlet 143 Conveyor outlet 144 Preheater 145 Thermal insulation cover 221 Through hole 222 Lead of electronic component 223 Solidified solder

Claims (5)

A flow soldering apparatus for mounting an electronic component on a substrate using a solder material, a solder tank for containing a molten solder material, a primary jet nozzle for primary jetting of the molten solder material, and the melting A flow soldering apparatus comprising: a secondary jet nozzle for secondary jetting of the solder material formed; and a partition wall disposed between the primary jet nozzle and the secondary jet nozzle. The partition wall has a height of 5 mm or more upward from the surface of the molten solder material placed in the solder bath and a height of 10 mm or more downward from the surface of the molten solder material placed in the solder bath. The flow soldering apparatus according to claim 1, wherein: 2. The flow soldering according to claim 1, wherein the partition is disposed on the primary jet side from the position where the primary jet and the secondary jet are mixed and the position where the secondary jet is mixed when the partition is not provided. apparatus. The flow soldering apparatus according to claim 1, wherein the partition wall is made of a material having low solder wettability. 2. The flow soldering apparatus according to claim 1, wherein the partition wall is made of stainless steel or stainless steel having chromium nitride on the surface.