JP2010267785A - Jet solder bath - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent oxidation of solder jetted from a nozzle. <P>SOLUTION: A cover body 40 has an opening portion 43 for inserting a nozzle portion 3 and a side wall 42 positioned outside from the opening portion 43, and covers a part of a solder housing portion 2. A supply pipe 45 has a plurality of supply ports 46 for supplying a nitrogen gas to the side wall 42 side, and is provided between the opening portion 43 and the side wall 42 so as to surround the opening portion 43. With this configuration, the nitrogen gas supplied from the supply ports 46 is supplied toward the side wall 42, and stored between the nozzle portion 3 and the side wall 42, and a liquid surface of the solder 20. The gas density of the stored nitrogen gas becomes high. The nitrogen gas having high gas density is jetted from the opening portion 43, and sprayed to the solder 20 jetted from the nozzle portion 3. Thus, oxidation of the solder can be prevented. As this result, bridge failure or icicle failure caused by solder adhering to a portion other than a predetermined portion can be prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a jet solder bath in which molten solder accommodated in a solder accommodating portion is caused to flow by a jet means and jetted from a nozzle, and gas is blown to the jetted solder.

  As a method of soldering to a printed circuit board, there is an immersion method in which the printed circuit board is brought into contact with molten solder and soldered. In this dipping method, flux is applied to a printed circuit board with a fluxer installed in a soldering apparatus, the application part is preheated with a preheater, solder is attached in a jet solder bath, and cooling is performed with a cooling device. Perform soldering.

  The jet solder tank installed in the soldering apparatus is composed of a solder accommodating portion for accommodating solder, a nozzle portion, a duct portion, a pump portion, and the like. In this jet solder bath, the solder accommodated in the solder accommodating portion is melted by an electric heater, the molten solder is jetted from the nozzle portion by the pump portion, and the printed circuit board is brought into contact with the jetted solder.

  When soldering to a printed circuit board in the atmosphere using such a jet solder bath, the solder may be oxidized by oxygen in the atmosphere. When the solder at the soldering portion is oxidized, the wettability of the solder is lowered, and a bridging defect or an icicle defect where the solder adheres to a portion other than a predetermined portion occurs. In particular, those defects are remarkably generated in a partial jet soldering apparatus used when retrofitting large electronic components such as connectors.

  Furthermore, when not only the solder in the soldering portion but also the molten solder in the jet solder bath is oxidized by oxygen in the atmosphere, an oxide is generated on the molten solder. The oxide is jetted from the jet nozzle together with the molten solder and adheres to the printed circuit board. When the oxide adheres to the printed circuit board, if the oxide is large, not only short-circuiting and lowering of insulation resistance occur between adjacent soldered portions, but also the appearance is deteriorated and the commercial value is lowered.

  Patent Document 1 discloses a partial soldering apparatus that supplies an inert gas. According to this partial soldering apparatus, a gas supply means for supplying an inert gas, a pipe connected to the gas supply means, and an inert gas around the nozzle portion connected to the pipe and into which the solder is jetted And an inert gas from the gas supply means is supplied to the gas nozzle part via a pipe. And a gas nozzle part sprays an inert gas toward a printed circuit board.

JP 2002-305372 A (FIG. 2)

  By the way, according to Patent Document 1, in a soldering apparatus that performs soldering locally, a gas nozzle that discharges nitrogen gas is provided at a jet port near the solder nozzle, and nitrogen gas is blown onto the soldering surface of the substrate. The oxygen concentration is lowered to prevent solder oxidation. However, since it is a direct-fired type in which a vigorous inert gas is blown directly onto the printed circuit board, nitrogen gas diffuses and the oxygen concentration on the soldering surface does not become constant. As a result, there is a problem that oxidation of the solder cannot be completely prevented and icicles cannot be suppressed.

  Further, according to the structure of Patent Document 1, when there are a plurality of solder nozzles for locally performing a plurality of solders in one jet solder bath, there is a problem that the oxygen concentration cannot be individually changed. The oxygen concentration optimal for soldering changes depending on various conditions such as the type of electronic components placed on the printed circuit board, the number of leads, the placement position, etc., so the oxygen concentration cannot be changed individually. And cause poor soldering.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a jet solder bath that can sufficiently supply an inert gas to solder jetted from a nozzle to prevent oxidation of the solder. To do.

  In order to solve the above-described problems, a jet solder bath according to the present invention is a jet solder bath in which molten solder accommodated in a solder accommodating portion is jetted from a nozzle by jet means, and gas is blown to the jetted solder. A cover body portion that has an opening for inserting the nozzle and a side wall located outside the opening, covers at least a part of the solder accommodating portion, and a plurality of supply ports that supply gas toward the side wall And a supply pipe provided between the opening and the side wall so as to surround the periphery of the opening.

  According to the jet solder bath according to the present invention, in the jet solder bath in which the solder accommodated in the solder accommodating portion is jetted from the nozzle by the jet means, and gas is blown to the jetted solder, the cover body portion inserts the nozzle And a side wall located outside the opening, and covers at least a part of the solder accommodating portion. The supply pipe has a plurality of supply ports for supplying gas toward the side wall, and is provided between the opening and the side wall so as to surround the periphery of the opening.

  Accordingly, a large amount of gas is supplied from the plurality of supply ports facing the side wall, so that the gas can be stored in a space between the side wall and the nozzle. The stored gas has a higher gas density than the gas supplied from the supply port. A gas having a high gas density is ejected from the opening, and the gas is sprayed onto the solder jetted from the nozzle.

  According to the jet soldering bath according to the present invention, the space between the side wall and the nozzle becomes a reservoir for an inert gas such as nitrogen gas, and the inert gas is temporarily stored in the reservoir and overflowed from the reservoir. Nitrogen gas is blown out around the nozzle. As a result, the inert gas concentration around the nozzle becomes uniform as compared with the conventional direct type, so that the oxygen concentration on the soldering surface of the substrate can be reduced, wettability can be ensured, and icicles can be suppressed. .

It is front sectional drawing which shows the structural example of the jet solder tank 1 which concerns on 1st Embodiment. 2 is a left side cross-sectional view showing a configuration example of a jet solder bath 1; FIG. It is a top view which shows the structural example of the jet soldering tank. It is a back view which shows the structural example of the supply apparatus. (A), (B), (C) is explanatory drawing which shows the operation example of the jet soldering tank 1. FIG. It is a back view which shows the structural example of 4 A of supply apparatuses which concern on 2nd Embodiment.

  A jet solder bath will be described below as an example of an embodiment according to the present invention with reference to the drawings.

<First Embodiment>
As shown in FIGS. 1 to 3, the jet solder tank 1 according to the present embodiment includes a solder housing part 2, a nozzle part 3, a duct part 7, a pump part 10, and a supply device 4.

  Solder 20 is accommodated in the solder accommodating portion 2. The solder 20 is, for example, lead-free solder, and is composed of Sn—Ag—Cu, Sn—Zn—Bi, or the like. The solder accommodating part 2 is provided with a pump part 10, a duct part 7 and a nozzle part 3 which are jet means. The jet solder tank 1 is configured such that the solder 20 accommodated in the solder accommodating portion 2 passes through the duct portion 7 by the pump portion 10 and jets the solder 20 from the nozzle portion 3 to a printed circuit board (not shown).

  The pump unit 10 includes a motor, an impeller 11 and a shaft 12 (not shown). When the motor is driven, the impeller 11 rotates through the shaft 12 and jets the solder 20 melted by a heater (not shown), and the solder 20 flows into the duct portion 7 in a predetermined inflow direction. The pump unit 10 can pump the solder 20 so that the pressure of the solder 20 applied to the duct unit 7 and the nozzle unit 3 is the same at any position by the Pascal principle. Thereby, the member which stabilizes the flow of the solder 20 called what is called a baffle plate becomes unnecessary. Further, almost no wave is generated in the solder 20 jetted from the nozzle portion 3. As a result, the liquid level of the solder 20 spouted from the nozzle part 3 can be kept constant at all times, and the solder 20 can be held flush with the nozzle part 3.

  The duct portion 7 is provided with the nozzle portion 3. The nozzle unit 3 jets the solder 20 that has passed through the duct unit 7 to a printed circuit board (not shown). As described above, the liquid level of the solder 20 jetted from the nozzle portion 3 is uniform. As a result, it is possible to reduce a bridging defect in which solder adheres to other than a predetermined portion of the printed circuit board and an unsolder defect in which solder does not adhere to a predetermined portion. A plurality of nozzle portions 3 may be provided corresponding to locations where soldering is performed locally. In the present embodiment, an example in which nozzles are provided at two locations is shown.

  A supply device 4 is provided on the upper part of the solder accommodating portion 2. The supply device 4 includes a cover main body 40 and a supply pipe 45. As shown in FIG. 3, the cover main body portion 40 has a fixing portion 47 and is fixed to the solder accommodating portion 2 through the fixing portion 47 so as to cover a part of the solder accommodating portion 2. The cover main body 40 has an opening 43. The opening 43 is larger than the nozzle 3 and is provided in the cover body 40 so as to surround the nozzle 3.

  A protrusion 41 is provided in the opening 43. As shown in FIGS. 1 and 2, the protrusion 41 protrudes upward and downward with respect to the cover main body 40. A side wall 42 is provided on the outer side of the protrusion 41. The side wall 42 is provided so that the front end of the side wall 42 is in contact with the solder 20 of the solder accommodating portion 2 or below the liquid level of the solder 20. In FIG. 1 and FIG. 2, the protruding amount of the side wall 42 is larger than the protruding portion 41 on the upper side, but as described above, if the tip of the side wall 42 is in contact with the solder 20 of the solder accommodating portion 2, The protruding amount may be smaller than that of the upper protruding portion 41.

  A supply pipe 45 is provided between the protrusion 41 and the side wall 42. The supply pipe 45 is provided with a plurality of supply ports 46 for supplying an inert gas such as nitrogen gas in the direction of the side wall 42. As will be described later, in the present embodiment, the space 9 between the side wall 42 and the nozzle portion 3 serves as a reservoir for an inert gas such as nitrogen gas, and the nozzle portion 3 is provided at two locations. Each storage part is provided independently.

  A nitrogen source 5 is connected to the supply pipe 45. The nitrogen source 5 supplies nitrogen gas to the supply pipe 45. A supply pipe 45 installed between the nitrogen source 5 and the cover main body portion 40 is disposed in the solder accommodating portion 2, and after the nitrogen gas is heated by the heat of the solder 20, the nitrogen gas is supplied from the supply port 46. May be. Thereby, it can prevent that a printed circuit board is cooled by nitrogen gas.

  Further, the concentration of nitrogen gas may be set to a desired concentration by providing a gas supply source containing oxygen such as oxygen gas or air (not shown) separately from the nitrogen source 5 and mixing. Thereby, when the nozzle part 3 is provided with two or more, since the space as a storage part is independently provided for every nozzle part 3, it is mounted in the printed circuit board of the site | part to which it solders locally. The mixing ratio of the nitrogen gas and the gas containing oxygen can be changed for each nozzle portion 3 in accordance with the type of electronic component. As a result, the oxygen concentration on the soldering surface of the substrate can be controlled for each nozzle portion 3. In addition, the mixing method of gas may be made to mix in a storage part, and may be made to mix on the piping side. In addition, although the storage part was provided independently for every nozzle part 3, when it is not necessary to consider the oxygen concentration for every nozzle part 3, you may make it provide a storage part in common.

  As shown in FIG. 4, the supply device 4 includes the cover main body 40 and the supply pipe 45 as described above. The supply pipe 45 is provided in the cover main body 40 so as to surround the opening 43. As described above, the supply pipe 45 is provided with a plurality of supply ports 46 on the side wall 42 side, and supplies a large amount of nitrogen gas toward the side wall 42. The plurality of supply ports 46 are arranged at equal intervals, and the sizes of the supply ports 46 are equal. The shape of the supply port 46 is preferably a circle, but can be changed as appropriate. The supply pipe 45 is preferably connected to the protrusion 41 and the side wall 42 in order to allow a sufficient inert gas such as nitrogen gas to be stored in the space surrounded by the nozzle part 3, the side wall 42, and the liquid level of the solder 20. It is desirable to arrange them at appropriate intervals.

  Next, an operation example of the jet solder bath 1 will be described. It is assumed that the solder 20 accommodated in the solder accommodating portion 2 is flowed by the pump portion 10, passes through the duct portion 7, and is jetted from the nozzle portion 3. As shown in FIG. 5A, the supply pipe 45 provided so as to surround the opening 43 supplies the nitrogen gas G1 from the supply port 46 toward the side wall 42 in the direction of the arrow A1. The nitrogen gas G1 supplied to the side wall 42 is stored from the side of the side wall 42, with the space 9 surrounded by the nozzle part 3, the side wall 42, and the liquid level of the solder 20 serving as a storage part for the nitrogen gas G1.

  As shown in FIG. 5B, the supply device 4 continues to supply the nitrogen gas G1 from the supply port 46 toward the side wall 42 in the direction of the arrow A1. Since a large amount of nitrogen gas G1 is supplied from the plurality of supply ports 46, the nitrogen gas G1 is sufficiently stored in the space 9. The stored nitrogen gas G1 has a higher gas density than the nitrogen gas supplied from the supply port 46.

  As shown in FIG. 5C, when the nitrogen gas G1 is continuously supplied from the supply port 46 in the direction of the arrow A1 toward the side wall 42, the nitrogen gas G1 stored in the space 9 as the storage portion is The solder 20 ejected from the opening 43 and sprayed from the nozzle 3 is sprayed onto the printed circuit board. Since the protrusion 43 is provided in the opening 43, the nitrogen gas G1 can be supplied uniformly toward the solder 20 and the printed circuit board S1.

  In the jet solder tank 1, solder is formed at a predetermined location by jetting the solder 20 sprayed with the nitrogen gas G1 onto the printed circuit board S1. The solder 20 is not oxidized because the nitrogen gas G1 having a high gas density is sprayed thereon. For this reason, it is possible to suppress a decrease in the wettability of the solder, and there is hardly any bridging defect or icicle defect where the solder adheres to other than a predetermined location.

  As described above, according to the jet solder tank 1 according to the present embodiment, the solder 20 accommodated in the solder accommodating portion 2 is caused to flow by the pump portion 10 and jetted from the nozzle portion 3, and the jetted solder 20 is applied to the solder 20. In the jet solder bath 1 for blowing the nitrogen gas G1, the cover main body portion 40 has an opening 43 for inserting the nozzle portion 3 and a side wall 42 located outside the opening 43, and a part of the solder accommodating portion 2 Cover. The supply pipe 45 has a plurality of supply ports 46 that supply the nitrogen gas G <b> 1 on the side of the side wall 42, and is provided between the opening 43 and the side wall 42 so as to surround the opening 43.

  Thereby, since a large amount of nitrogen gas G1 is supplied from the plurality of supply ports 46, the nitrogen gas G1 can be stored in the space 9 surrounded by the side wall 42, the nozzle portion 3 and the liquid surface of the solder 20. The stored nitrogen gas G1 has a higher gas density than the nitrogen gas supplied from the supply port 46. Nitrogen gas G1 with increased gas density is ejected from opening 43, and nitrogen gas G1 is sprayed onto solder 20 that is jetted from nozzle portion 3.

  As a result, since the nitrogen gas G1 having a high gas density can be sprayed onto the solder 20 jetted from the nozzle portion 3, oxidation of the solder 20 can be prevented. As a result, it is possible to reduce bridging defects and icicle defects in which solder adheres to areas other than predetermined places.

  In the present embodiment, the nitrogen gas G1 is stored in the space surrounded by the nozzle portion 3, the side wall 42, and the liquid surface of the solder 20 as a storage portion. The space surrounded by the portion 3, the side wall 42, and the bottom plate may be stored as a storage portion.

<Second Embodiment>
In the present embodiment, a supply device 4A in which supply ports are arranged at unequal intervals will be described. Components having the same names and reference numerals as those of the above-described embodiments and examples have the same functions, and thus description thereof is omitted.

  As shown in FIG. 6, the supply device 4A includes a cover main body 40 and a supply pipe 45A. The supply pipe 45 </ b> A is provided so as to surround the opening 43. Supply ports 46A, 47A, 48A, and 49A are provided in the supply pipe 45A. Supply ports 46 </ b> A, 47 </ b> A, 48 </ b> A, 49 </ b> A are formed on the side wall 42 side, and supply nitrogen gas toward the side wall 42.

  The supply ports 46A are arranged such that the intervals between the supply ports 46A are the same as the intervals of the supply ports 46 described in the above-described embodiment. The size of the supply port 46 </ b> A is the same as the size of the supply port 46. The supply port 47A is arranged such that the interval between the supply ports 47A is smaller than the interval between the supply ports 46A. The size of the supply port 47A is the same as the size of the supply port 46A. The supply port 48A is arranged such that the interval between the supply ports 48A is smaller than the interval between the supply ports 47A. The size of the supply port 48A is larger than the size of the supply ports 47A and 46A. The supply port 49A is arranged with the same interval between the supply ports 49A as the interval between the supply ports 48A. The size of the supply port 49A is the same as the size of the supply port 48A.

  The relationship between the intervals and sizes of the supply ports 46A, 47A, 48A, and 49A may be appropriately changed depending on the length and size of the supply pipe, the flow rate of the nitrogen source, and the like.

  As in the case of the supply pipe 45 described in the first embodiment, the nitrogen gas G1 supplied from the supply port 46 close to the nitrogen source 5 is the nitrogen source if the intervals and sizes of the supply ports 46 are equal. The flow rate of the nitrogen gas G1 is larger than that of the supply port 46 far from 5. However, as described above, by providing the supply ports 46A, 47A, 48A, and 49A in the supply pipe 45A, the nitrogen gas G1 having the same flow rate can be supplied to any of the supply ports 46A, 47A, 48A, and 49A. . Thereby, nitrogen gas G1 with a stable gas flow rate can be sprayed onto the solder 20.

  Thus, according to the supply device 4A according to the present embodiment, the supply port 46A closest to the nitrogen source 5, the supply port 47A closest to the nitrogen source 5 and the supply port closest to the third from the nitrogen source 5 are provided. By changing the interval and the size of the supply port 49A farthest from 48A and the nitrogen source 5, the nitrogen gas G1 having the same flow rate can be supplied to any of the supply ports 46A, 47A, 48A, 49A. Become. Thereby, the more stable nitrogen gas G1 can be sprayed on the solder 20, and bridge | bridging defect and icicle defect can be reduced in the solder formed in printed circuit board S1.

DESCRIPTION OF SYMBOLS 1 Jet solder tank 2 Solder accommodating part 3 Nozzle part 4, 4A Supply apparatus 5 Nitrogen source 7 Duct part 9 Space 10 Pump part 20 Solder 40 Cover main-body part 41 Projection part 42 Side wall 43 Opening part 45 Supply pipe 46, 46A, 47A, 48A, 49A supply port

Claims (9)

In the jet solder bath in which the molten solder accommodated in the solder accommodating portion is jetted from the nozzle by the jet means, and gas is blown to the jetted solder,
A cover main body having an opening for inserting the nozzle and a side wall located outside the opening, and covering at least a part of the solder housing;
A plurality of supply ports for supplying the gas toward the side wall, and a supply pipe provided between the opening and the side wall so as to surround the opening. The jet solder bath according to claim 1.   The jet solder bath according to claim 1, wherein the gas is an inert gas.   The jet solder bath according to claim 1, wherein the gas includes an inert gas and a gas containing oxygen.   The jet solder bath according to claim 3, wherein the gas has a variable mixing ratio between an inert gas and a gas containing oxygen.   The jet solder bath according to claim 1, wherein a protrusion is provided in the opening.   The jet solder bath according to claim 1, wherein the plurality of supply ports are arranged at equal intervals.   The jet solder bath according to claim 1, wherein the plurality of supply ports are arranged at unequal intervals.   The jet solder bath according to claim 6 or 7, wherein the plurality of supply ports have the same size.   The jet solder bath according to claim 6 or 7, wherein the plurality of supply ports have different sizes.

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