KR910003702B1 - Automatic soldering apparatus - Google Patents

Abstract

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Description

Automatic Soldering Device and Method

1 to 8 relate to a first embodiment of the present invention,

1 is a schematic side view of the whole of an automatic soldering apparatus.

2 is a plan view of FIG.

3 is a longitudinal sectional front view of the flux applicator.

4 is a side longitudinal sectional view of FIG.

Fig. 5 is a schematic front longitudinal sectional view showing a modification of the flux applicator of Fig. 3.

6 is a perspective view of a heater for flux heating.

7 is a longitudinal sectional view showing a state in which a multilayer printed circuit board is in contact with a solder bath.

8 is a schematic front longitudinal sectional view showing a state in which a substrate is cleaned and cooled by a cooling and cleaning device.

9 and 10 relate to a second embodiment of the present invention,

9 is a front longitudinal sectional view of the flux applicator.

10 is a side longitudinal sectional view of FIG.

11 and 12 relate to a conventional example,

11 is an overall schematic side view of an automatic soldering apparatus.

12 is a plan view of FIG.

＊ Explanation of symbols for main parts of drawing

11, 71: automatic soldering device 12, 72: conveying device

13, 13A, 73: flux coating device 14: soldering tank

16: soldered substrate 25 ': molten solder

29, 29A: flux heating heater 49: flux

52: surplus flux removal device 54: brush

55 cooling and washing device

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to an automatic soldering method and apparatus, and in particular, by heating the flux and contacting the soldered surface of the soldered substrate, the flux application and the preheating of the soldered substrate can be carried out simultaneously. The present invention relates to a revolutionary automatic soldering method and apparatus that enables even heating and eliminates or reduces the size of a conventional preheater, thereby greatly reducing power and miniaturizing the apparatus.

Conventionally, the soldering process of a printed wiring board (printed board) has been mainly performed in order of flux application, preheating, soldering, and cooling. Flux was mainly used as a liquid that was dissolved in a solvent such as isopropyl alcohol (IPA) by adding an active agent such as hydrochloride of a lower amine such as ethylamine to the resin of the rosin system.

The action of flux is mainly to remove the metal circuit surface of printed circuit board and metal surface oxide of soldered electronic component by activator, and to lower the surface tension of solder by resin component such as rosin. Known. In addition, the isopropyl alcohol used for the liquid flux has not only the above-mentioned deactivating agent and the dissolving agent of the resin component, but also serves as a diluent for imparting uniform compatibility to the printed circuit board and controlling the amount of flux adhering. The flux was usually applied in contact with a printed circuit board in a foamed state, but was always used only at room temperature.

Preheating is then carried out for the purpose of removing the solvent in the liquid flux, activating the active agent and preheating the printed board. That is, by preheating the solvent in the liquid flux sufficiently to prevent contact with the high temperature solder during the soldering of the next step to explode the volcanic solvent and prevent the uniform compatibility of the solder. Preheating conditions are generally set to 40-120 ° C because the thermal shock can be alleviated by advancing the activation by heating or by raising the temperature of the printed board itself and reducing the solder temperature and temperature difference. Is set.

That is, as shown in FIG. 11 and FIG. 12, in the conventional automatic soldering apparatus 1, the conveying apparatus 2 and the flux application apparatus 3 which convey a to-be-soldered board, and molten solder are accommodated The solder tank 4 and the preheating apparatus 5 were provided, and the air curtain apparatus 6 and the cooling apparatus 8 were provided. In the preheater 5, the soldered substrate was indirectly heated through the air layer in the middle by a heater 9 such as a nichrome wire heater or an infrared heater. Soldering in the solder bath 4 is performed by contacting a soldered solder substrate with molten hot solder, but there are two types of contact methods, ones by solder classification and one by solder dipping. Moreover, although cooling performed in order to minimize the disturbance by the heat of a to-be- soldered board | substrate was performed by cold air normally, this tended to solidify a solder rapidly.

In the conventional automatic soldering apparatus 1 in which the flux at normal temperature is applied to the soldered substrate in the flux coating apparatus 3 as described above, the additional soldering apparatus 5 is heated. There was such a flaw.

(1) Since the process of foaming and applying the flux containing the highly flammable organic solvent, and the process of heating and removing the solvent are performed continuously, access of a phosphide and a high temperature part cannot be avoided. The risk of back was high.

(2) Not only does it require a large amount of heat to evaporate the organic solvent, but also requires a large amount of energy to heat the soldered substrate.However, in the method of heating through an air layer in the middle by a heater, air has a low thermal conductivity and a density. Since the preheating capacity is small, the thermal efficiency is low because the preheating capacity is small. Therefore, it is necessary to increase the output of the heater, increase the number of heaters, or lengthen the heating time by the heater. As shown in Figs. 12 and 12, the preheating device 5 has a considerably large size, and occupies about 20% of the entire length of the automatic soldering device 1.

(3) In the case of a soldered substrate, particularly in a large heat capacity, for example, a large printed circuit board having a large number of layers, a poor thermal conductivity, for example, a ceramic substrate, it is extremely important to uniformly heat the soldered substrate in a short time. It is difficult or impossible, and there is a great fear of a poor soldering.

The present invention has been studied to solve the above-mentioned drawbacks of the prior art, and the first object is to replace the flux using a conventional organic solvent, the non-flammable or highly flammable, low evaporation solvent activation temperature is the heating temperature of the flux At a higher heating temperature of the flux, a flux heating device is provided with a heater for flux heating using a dissolved active agent or a mixture of a stable active agent and a solvent or an additive having good compatibility with the active agent. The preheating device which required a large electric power in the prior art by heating a flux and making it contact a soldered surface of a to-be-soldered board, carrying out a flux application and preheating a to-be-soldered board simultaneously and soldering is needed. It can be reduced or reduced in size, and it is possible to drastically reduce power consumption and shorten the length of the automatic soldering apparatus. The second object is to use a liquid flux having a much higher density and heat capacity than air as a heating medium, without using air as a heating medium, thereby greatly improving the thermal efficiency when heating the soldered substrate, and making it uniform in a short time with low energy. In this way, the soldered substrate can be heated to a desired temperature. The third purpose is not to evaporate the organic solvent by not using the organic solvent in the flux, to eliminate the energy loss due to the heat of vaporization, to prevent the occurrence of pollution, and to eliminate the risk of fire.

The fourth purpose is to heat the soldered solder substrate with excellent efficiency by the heated flux, so that large-scale large-scale printed circuit boards with large heat capacity or ceramic substrates with poor thermal conductivity can be heated evenly and uniformly over the entire thickness of the board. To make it possible. This improves the compatibility of the solder in the soldering process and dramatically improves the soldering performance of these large substrates.

The fifth purpose of the preheating by flux is to reduce the thermal shock to the soldered substrate by contacting the soldered substrate with the high temperature flux from the low temperature flux in order with respect to the traveling direction of the soldered substrate. This is to prevent deformation due to.

The sixth object is to install a redundant flux removal device for removing excess flux applied to the soldering substrate, so that a large amount of flux can be recovered because it is a high temperature flux, thereby saving flux and saving flux. It is to prevent the damage of surplus flux.

The seventh object is to use a flux having high heat resistance so that the surface of the molten solder can be covered with the flux, and the oxidation of the molten solder is prevented.

The eighth purpose is to install a cooling and cleaning device for contacting the cooling and flux cleaning fluid to the soldered soldered substrate in the soldering tank to completely remove the flux which is attached more than the conventional flux and to complete the cooling process. It does not interfere with the handling of Esau.

In short, the method of the present invention is characterized in that the flux is heated, the heated flux is brought into contact with the soldered surface of the soldered substrate, the flux is applied and the preheated soldered substrate is simultaneously subjected to soldering. . The device (second invention) of the present invention is provided with a conveying apparatus for conveying a soldered substrate, a flux applying apparatus, and a solder bath in which molten solder is accommodated, wherein the flux applying apparatus includes a heater for heating the flux. The flux heated by the heater is brought into contact with the soldered surface of the soldered substrate, so that the flux is applied and the preheating of the soldered substrate is carried out simultaneously. In addition, the present invention (third invention) is provided with a conveying apparatus for conveying a soldered substrate, a flux applying apparatus, and a solder bath for receiving molten solder, wherein the flux applying apparatus includes a heater for heating the flux. The flux heated by the heater is brought into contact with the soldered surface of the soldered substrate so that the flux is applied and the soldered substrate is preheated at the same time, and the extra flux applied to the soldered substrate is applied. It is characterized by including a surplus flux removing device for removing. In addition, the present invention (fourth invention) is provided with a conveying apparatus for conveying a soldered substrate, a flux applying apparatus, and a solder tank for receiving molten solder, wherein the flux applying apparatus includes a heater for heating the flux. And the flux heated by the heater is brought into contact with the soldered surface of the soldered substrate so that the flux is applied and the soldered substrate is preheated at the same time, and the soldered substrate in the solder bath is cooled in the soldered substrate. And a cooling / cleaning device for contacting the double-flux cleaning fluid.

EMBODIMENT OF THE INVENTION Below, this invention is demonstrated according to the Example shown by drawing. 1 to 8 show a first embodiment of the apparatus of the present invention, wherein the automatic soldering apparatus 11 of the present invention includes a conveying apparatus 12, a flux applying apparatus 13, and a solder bath 14 In addition, the flux coating device 13 includes a heater 29.

The conveying apparatus 12 is for conveying the to-be- soldered board 16 (henceforth a board | substrate), The endless chain 19 wound around the several sprocket 18 like this conventional example, A plurality of carriers 20 and a chain driving mechanism (not shown) connected to the chain and traveling together with the chain, and the chain 19 is the flux coating device 13 and the solder bath in this embodiment. At 14, the substrate 16 mounted on the carrier 20 is lowered at an angle. The carrier 20 includes two carrier bars 22 inserted into and communicated with the frame 21 and four wheels 23 and a substrate device tool 24 which are pivotally mounted at both ends of the carrier bar 22. ), One end 22a of the carrier bar 22 is connected to the chain 19, and the wheels 23 are configured to transmit on the guide rail 25. The board | substrate apparatus tool 24 is provided in multiple numbers, and the upper end is attached to the frame 21, and is comprised so that the board | substrate 16 may be suspended by the lower end.

The solder bath 14 is disposed immediately after the flux application device 13, and the conventional preheater 5 (FIG. 11) is removed. Molten solder 25 'is accommodated in the solder tank 14, and the heater 26 is provided in the lower part.

The flux spreading device 13 has a flux heating heater 29 at its bottom 28, which is, for example, the heating element 30 being poured into the aluminum block 31 as shown in FIG. 6. Exposed aluminum injection heater 32 is arranged in a plurality of rows. The heater 29 is in close contact with the bottom plate 33a of the flux tank 33, and the heat insulating material 35 is filled between the side plate 33b and the outer plate 34 of the flux tank 33. An overflow tank 36 is disposed in the flux tank 33, and the overflow tank is composed of a flux conveying part 38 and an overflow part 39, and the partition plate 40 has a flux rising. The flow path 40a is formed in the bottom plate 41 with the flux suction path 41a, respectively. The impeller 42 of the flux pumping pump P is immediately fixed to the rotating shaft 43 and disposed as a rotating material immediately above the passage 41a, and the rotating shaft 44a of the variable speed motor 44 is disposed on the rotating shaft 43. The poly 48, on which the belt 46 is wound, is fixed to the poly 45 secured to the poly 45. The flux 49 accommodated in the flux tank 33 is heated to 40-120 ° C. by the heater 29, is sucked into the flux conveying part 38 by the impeller 42, and enters the overflow part 39. And overflow from 36a. In addition, the flux tank 33 is attached to the base 51 which height adjustment is possible, for example by four tank level jacks 50. As shown in FIG.

The surplus flux removal device 52 is configured such that a brush 54 is provided on an upper end of the flux return plate 53 inclined in front of the carrier traveling direction of the flux tank 33. For example, a nylon material can be used for the brush 54, and the excess flux 49 applied to the lower surface of the substrate 16 is mechanically removed. Instead of such a mechanical brush, an air brush (not shown) in which the flux 49 is removed by the injection of compressed air may be used.

The cooling and cleaning device 55 is configured to eject the fluid 56 by causing the cooling and cleaning fluid 56 to contact the soldered solder substrate 16 in the solder bath 14. The container 58, the injection pump 59, the injection nozzle 60, and the fluid receiving port 61 are provided (see FIG. 8). The fluid 56 uses water, hot water, or a water-based liquid such as 1% caustic soda when the flux 49 is water-soluble, and when the flux is water-insoluble. For example, a pron solvent, a chlorine solvent or an alcohol solvent is used.

In addition, in FIG. 1, 62 is an air curtain apparatus, and is intended to insulate the board | substrate 16 heated by the flux coating apparatus 13, and to convey it to the solder tank 14. As shown in FIG.

Next, shown in FIG. 5 is a flux application device 13A according to the deformation of the flux application device 13 shown in FIGS. 3 and 4, and the pipe 63 is provided at the bottom of the flux tank 33A. This pipe is connected to the bottom of the overflow tank 36A via the pump P, and is configured to circulate the flux 49 through the flux tank 33A between the heaters 29A. The excess flux removing device 52A is provided at the upper left end of the flux tank 33A in the drawing, and is configured such that the brush 54A contacts the lower surface 16a of the substrate 16.

9 and 10 are the main parts of the automatic soldering apparatus 71 according to the second embodiment of the present invention, and the flux application device 73 is the flux application device 13 of the first embodiment. Is substantially the same as the above, except that only the capacity of the flux tank 33 and the capacity of the heater 29 can be set small, so that the same reference numerals are used in the drawings for the same parts as those of the first embodiment, and the description thereof is omitted. do. Unlike the first embodiment, the conveying device 72 is configured such that the wheels 23 of the carrier 2 are configured to allow the rail 75 to be vertically moved up and down, and the rails 75 are vertically moved at a predetermined timing. The plate 76 is fixed, and this connecting plate is connected to the piston rod 79 of the rail up-down cylinder 78. By the operation of the cylinder 78, the rail 75 moves up and down, and on the flux application device 73, the carrier 20 is configured to move up and down between the positions indicated by the virtual line and the solid line.

The mechanical structure of the present invention is as described above. Next, the flux 49 used in the automatic soldering method and apparatus of the present invention will be described. In the present invention, since the flux 49 itself is always heated to 40-120 ° C., since the evaporation of the solvent and the degradation of the activator are inevitable, the liquid flux used for soldering or conventional soldering is intact. There is a limit to the use in the invention.

The liquid flux 49 used in the present invention differs depending on the range in which the heating temperature of the flux is set, but the activation temperature (the temperature at which the activator starts to exert its capacity as a flux) for a non-combustible or low flammable solvent. ) Is higher than the heating temperature of the flux, and at the heating temperature of the flux, it is preferable to dissolve or mix a stable active agent and an additive component having good compatibility with the solvent or the active agent. As an example, the present invention includes a tricresyl formate (heat protector, active aid, solubilizer and extender), a phosphoric acid (active agent), and a flux and dibutyldicholol adipate containing 2,3-dibrompropanol (active agent) ( It has been found that fluxes comprising a heat resistant agent, an active aid, a solubilizer and an extender), phosphoric acid (active agent) and 2, 3-dibrompropanol (active agent) can be used.

In addition, in the description of the above embodiment, the flux 49 in the flux application devices 13, 13A, and 73 is heated to the same temperature, but this is divided into a plurality of flux tanks so that the heater 29 of each flux tank is By changing the capacitance, the substrate can be configured to contact with the hot flux at a low temperature from the low temperature flux in order with respect to the traveling direction of the substrate 16.

This invention is comprised as mentioned above and the effect | action is demonstrated below. 1 to 8, in the flux tank 33 of the flux coating device 13 of the automatic soldering apparatus 11 according to the present invention, a heatable flux 49 different from the conventional one is housed. Electricity is supplied to the heat generating element 30 of the reference numeral 29. As a result, the flux 49 is heated to 40-120 ° C. via the flux tank 33, while the solder 25 is energized by the heater 26 in the solder tank 14 to form the molten state.

Therefore, when the substrate 16 with the carrier 20 proceeds as shown by arrow A by the transfer device 12, the chain 19 descends obliquely downward, so that the substrate 16 together with the carrier 20 is flux-applied ( 13 is in contact with the flux 49 in the overflow tank 36. The flux 49 is sucked up by the impeller 42 which rotates through the pulley 45, the belt 46, the pulley 48, and the rotating shaft 43 by the rotation of the motor 44, and the pumping part 38 is carried out. Flows from the overflow portion 39 to the overflow portion 33 from the overflow portion to the flux tank 33. When the bottom plate 33a flows, it is heated by the heater 29 and circulated in the same manner. Therefore, the flux 49 which contacts the lower surface of the board | substrate 16 is always heated at low temperature, and the liquid flux 49 has a density and heat capacity especially compared with the air which is the heat medium in the conventional preheater. Due to its size, the substrate 16 is heated to a desired temperature uniformly in a short time, for example, in a conventional 1 / 4-1 / 6 time. Application of the flux 49 and heating of the substrate 16 are completed at the same time. In addition, when the flux 49 is applied and the substrate 16 is in the heating process, the conveying apparatus 12 is stopped for several seconds. When the process is completed, the conveying device 12 is operated again to operate the chain 19 to operate the carrier 20. ) And the substrate 16 are raised at an angle as shown by the arrow B and separated from the flux coating device 13. In this case, since the flux 49 is attached to the substrate 16 in a larger amount than the conventional room temperature flux, the application amount thereof is large, so that the brush 54 of the excess flux removing device 52 contacts the lower surface of the substrate 16. The surplus flux 49 is removed by sliding, and the flux adhering to the substrate 16 becomes an appropriate amount.

During the transfer between the flux application device 13 and the solder bath 14, the air curtain device 62 is operated so that the heated substrate 16 reaches the solder bath 14 while being maintained at an appropriate temperature. With the carrier 20, it descends to the surface of the molten solder 25 'and contacts this molten solder 25', and soldering is performed. In this case, unlike in the conventional case, since the substrate 16 is uniformly heated at each portion, the solder 25 'has good fusion adhesion and extremely good compatibility, and in particular, a large-sized multilayer printed circuit board or a ceramic substrate having poor thermal conductivity. Even good soldering can be ensured. For example, in the conventional preheating method in the four-layer substrate 16 as shown in FIG. 7, the temperature gradient on the lower surface 16a and the upper surface 16b is large, and the temperature of the upper surface 16b is considerably low. Since soldering was performed, the solder did not rise to the upper surface 16b or, for example, the solder was not compatible with the lead wire 80a, the terminal, etc. of the electronic component 80, but in the present invention, Also in such a multilayer substrate 16, the temperature of the upper surface 16b rises without a large difference from the lower surface 16a, so that the adhesion of the solder to the upper surface 16b or the electronic component 80 becomes extremely good.

When the soldering is completed in this manner, the conveying apparatus 12 is operated again and the substrate 16 arrives at the cooling / cleaning apparatus 55. In this apparatus, the injection pump 59 is operated so that the cleaning fluid 56 is operated. Since the liquid is circulated in the container 58 to be injected from the nozzle 60 as shown by arrow C and accommodated in the receiving mechanism 61 as shown by arrow D, the substrate 16 is shown in FIG. 8 due to the rapid flow rate of the fluid 56. ), Unnecessary flux 49 or debris of the solder 25 'is neatly removed, and at the same time, the substrate 16 is cooled to an appropriate temperature and the solder 25' is rapidly solidified. The temperature is good to handle and all processes are complete. In addition, the fluid 56 can be stopped and the substrate 16 can be brought into contact with it to perform cleaning and cooling.

In addition, according to the first embodiment, the capacity of the flux tank 33 and the heater 29 of the flux application device 13 is somewhat increased, but the mechanism is simple, the cost is reduced, and must be conveyed in the flux application process and the soldering process. There is no need to stop the device, so the continuous operation is possible.

Next, the operation of the automatic soldering apparatus 71 of the second embodiment shown in FIGS. 9 and 10 will be described. In this embodiment, the conveying device 72 is different from the first embodiment, when the carrier 20 proceeds as shown by the arrow E by the chain 19 and reaches directly above the flux applying device 73, the cylinder 78 ), The piston rod 79 is lowered integrally, and a portion of the rail 75 is lowered from the position of the imaginary line to the position of the solid line by the part of the rail 75 via the connecting plate 76, and the board 16 The lower surface of the () is in contact with the heated flux 49, the flux is applied at the same time the appropriate temperature is heated. In the meantime, the chain 19 is temporarily stopped.

As such, when the flux 49 is applied to the substrate 16 and the heating is completed, the cylinder 78 is operated again so that the piston rod 79 is raised and lowered in part, so that a part of the rail 75 is lowered like the other part. After returning to the height, the chain 19 and the chain 19 start to proceed as shown by arrow E, and soldering is performed. In addition, since the operation | movement in the flux application apparatus 73 is the same as that of 1st Example, duplication description is abbreviate | omitted. As described above, when the carrier 20 is commonly used on the flux applying device 73, the carrier device 72 moves up and down in the directions of arrows F and G, the carrier device 72 must be used in the application and heating process of the flux 49. ), And the rail raising and lowering cylinder 78, etc., are required, so that the mechanism is complicated and expensive, while the capacity of the flux tank 33 and the heater 29 is different from that of the first embodiment. There is an advantage that can be made smaller in comparison.

Since the present invention is configured and functions as described above, the activation temperature is higher than the heating temperature of the flux in the nonflammable or low flammable and low evaporation solvent instead of using the flux in the conventional organic solvent. Using a safe active agent dissolved or mixed with a solvent or an additive having excellent compatibility with the active agent, a flux heating apparatus is installed in the flux application device, and the flux is heated by this heater, and the heated flux is soldered. Contacting the soldered surface of the board and soldering the flux at the same time as preheating of the soldered board allows the soldering device to be used without the need for a large power source or to be miniaturized. And the length of the automatic soldering apparatus can be shortened. In addition, it is possible to use a liquid flux having a higher density and heat capacity than air as a heating medium, without using air as a heating medium, thereby greatly improving the thermal efficiency when heating the soldered substrate, and in a short time and uniformly using less energy. In this way, the soldered substrate can be heated to a desired temperature. In addition, since no organic solvent is used as the flux, there is no need to evaporate the organic solvent, and it is possible to eliminate energy loss due to heat of vaporization, to prevent pollution, and to eliminate the risk of fire. .

In addition, the soldered substrate is effectively heated by the heated flux, so that a large printed circuit board having a large heat capacity or a ceramic substrate having poor thermal conductivity can be heated evenly and uniformly over the entire thickness of the plate. This has the effect of improving the compatibility of the solder in the soldering process and drastically improving the solderability of these large substrates.

In addition, the preheating by the flux is performed by contacting the soldered substrate with the high temperature flux at the low temperature flux in order with respect to the advancing direction of the soldered substrate, thereby alleviating the thermal shock to the soldered substrate. There is an effect of preventing deformation due to.

In addition, since a redundant flux removal device for removing excess flux applied to the soldering substrate is provided, a large amount of flux applied due to the high temperature flux can be recovered, and the flux can be saved, and the excess in the soldering process can be achieved. There is an effect that can prevent the flux damage.

In addition, since the heat resistant flux is used, the surface of the molten solder can be coated with the flux, and there is also an adhesive effect that can prevent oxidation of the molten solder. In addition, since the cooling and cleaning device for injecting the cooling and flux cleaning fluid is installed in the soldering substrate in which the soldering is completed, the flux attached to a little more than the conventional flux is completely removed and the cooling is completed. It does not interfere with the effect.

Example 1

About the method by which the temperature rise of the surface of this board | substrate by the heating of a to-be- soldered board (printed circuit board) is made by the infrared heater used for the conventional automatic soldering apparatus, and the method of making it contact the flux heated at high temperature by this invention. Compared.

As the test object, an epoxy resin copper clad laminate (50 mm x 50 mm) based on glass having a comb electrode for measuring insulation resistance according to JIS C6480 was used, and the electrode surface was heated to increase the temperature of the opposite side. Investigated. The temperature rise was measured by adhering an irreversible temperature indication label (thermo-label) to the surface of the test object and reaching the indicated temperature.

In the heating by an infrared heater, the test object is stopped at a position where the temperature of the electrode surface becomes about 120 ° C. In the method of contacting the high temperature flux, the liquid flux having the composition shown below is heated to 120 ° C and the It heated by making the surface contact the electrode of a test object.

[The composition of the flux]

Tricresyl phosphate 100 parts by weight

3 parts by weight of phosphoric acid

5 parts by weight of 2,3-dibrompropanol

As a result of the test, in the conventional method, the time required for the substrate surface to reach 43 ° C is 28 seconds, 48 ° C is 45 seconds, 71 ° C is 90 seconds, 76 ° C is 110 seconds, and 82 ° C is 135 seconds. I did it.

In contrast, in the method of the present invention, the time to reach 43 ° C is only 7 seconds (shortened to 1/4), 48 ° C to 10 seconds (shortened to 1/4), and 71 ° C to 17 seconds (1 / Shortened to 5.3), 20 seconds to 76 ° C (reduced to 1 / 5.5), and 23 seconds to 82 ° C (reduced to 1 / 5.9).

From the above results, it is clear that according to the method of the present invention, the heating time of the substrate can be shortened to about 1 / 4-1 / 6 as compared with the conventional method.

Although the data are not disclosed, the same test was carried out on the large substrate, and as a result, the temperature distribution of the preheated method according to the present invention was more uniform than that of the conventional method.

Example 2

The surface to be soldered of the multilayer (4 layers) glass epoxy clock printed circuit board was brought into contact with the liquid flux under the conditions shown below, and the solder was applied after the flux was applied and the substrate was preheated.

[The composition of the flux]

100 parts by weight of dibutyl diglycol adipate

3 parts by weight of phosphoric acid

2 parts by weight of 2,3-dibrompropanol

Flux temperature, 120 ℃

Contact time 30 seconds

At this time, the surface temperature of the component top surface (surface which is not in direct contact with the flux) of the substrate was about 90 ° C.

The substrate was immediately brought into contact with the solder bath at 250 DEG C. As a result, the rise of the solder through the through-hole started in 2 seconds after the contact with the solder bath and was completed in 5 seconds.

On the other hand, commercially available flux (solvent isopropyl alcohol) containing hydrochloride, embrittlement hydrochloride, etc. of various amines as an activator mainly using modified rosin, which is widely used in the past, is applied with a flux coating apparatus. In the conventional soldering method in which the solvent is removed and preheated (heated for about 1 minute so that the surface temperature is about 90 ° C) by the infrared heater and brought into contact with the solder bath, the rise of the solder through the through-hole is dependent on the commercial flux type. Although the rise of the solder is relatively good, it started at 5 seconds after the contact and completed at 10 seconds.

That is, if the glass epoxy clock printed circuit board of the multilayer (four layers) is soldered under the same conditions, the rise of the solder through the through-holes is completed in about 1/2 of the time according to the method according to the present invention. It turned out.

Thus, according to the automatic soldering method and apparatus of the present invention, it can be seen that the solderability is much improved than the conventional example.

Claims (10)

The flux 49 is heated to contact the heated flux with the soldered surface of the soldered substrate 16, and the flux is applied simultaneously with the preheating of the soldered substrate, followed by soldering. Automatic soldering method. The method of claim 1, wherein the flux is incombustible or low flammability, the activation temperature is higher than the heating temperature of the flux in a low evaporation solvent, and the compatibility of the active agent and the solvent and the active agent stable at the heating temperature of the flux An automatic soldering method characterized by melting or mixing a good additive component. The method of claim 1 or 2, wherein the flux contains tricresyl phosphate, phosphoric acid, and 2,3-dibrompropanol. The soldering method according to claim 1 or 2, wherein the flux contains dibufildiglycol adipate, phosphoric acid and 2,3-dibrompropanol. The automatic soldering method according to claim 1, wherein the preheating by the flux causes the soldered substrate to contact with the hot flux at a low temperature flux in order with respect to the traveling direction of the soldered substrate. In the automatic soldering apparatus (11, 71) provided with the conveying apparatus (12, 72) which conveys a to-be- soldered board | substrate, the flux application apparatus (13, 13A, 73), and the solder tank 14 in which molten solder is accommodated, The flux application device includes heaters 29 and 29A for heating the flux, and the flux is heated by bringing the flux 49 heated by the heater into contact with the soldered surface of the soldered substrate 16. And a pre-heating of the soldered substrate at the same time. An automatic soldering apparatus including a conveying apparatus for conveying a soldered substrate, a flux applying apparatus, and a solder bath accommodating molten solder, wherein the flux applying apparatus includes a heater for heating the flux. The excess flux removal device is configured to simultaneously apply the flux and this preheating of the soldered substrate by bringing the heated flux into contact with the soldered surface of the soldered substrate, and also removes excess flux applied to the soldered substrate. An automatic soldering apparatus, comprising: 52. 8. The automatic soldering apparatus according to claim 7, wherein the excess flux removing device is a brush (54) for mechanically removing the excess flux. The automatic soldering apparatus according to claim 7, wherein the excess flux removing device is an air brush for removing the excess flux by injection of compressed air. An automatic soldering apparatus including a conveying apparatus for conveying a soldered substrate, a flux applying apparatus, and a solder bath accommodating molten solder, wherein the flux applying apparatus includes a heater for heating the flux. The heated flux is brought into contact with the soldered surface of the soldered board to simultaneously apply flux and preheat the soldered board, and to cool and flux clean the soldered substrate in the solder bath. An automatic soldering apparatus comprising a cooling and washing device (55) for contacting a fluid.

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