JPS62192261A - Vapor phase type soldering device - Google Patents

Abstract

PURPOSE:To heat uniformly the whole of an object to be soldered, and to obtain a uniform soldering property by providing a vapor supplying part for supplying locally heated vapor to the upper face of the object to be soldered, separately from a vapor phase formed in a vapor tank, on the upper side of a carrying path of the object to be soldered. CONSTITUTION:A heating medium liquid 22 of the lower part of a vapor tank 21 is evaporated by a heating action of a heater 23 in the liquid, and a vapor phase 24 is formed. Accordingly, when a printed circuit board P is carried into the vapor phase 24, solder which has been made to adhere to the board P is melted by a vaporization latent heat. Also, a part of the heated vapor is supplied from a blow-off nozzle 34 through an ascending duct 33, and heated vapor 36 is supplied locally from a blow-off port 35 to the center part of the upper face to which heating is a little insufficient, in the printed circuit board P, separately from the vapor phase 24. Accordingly, the whole of the board P and loaded parts W are heated uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Objective of the Invention) (Industrial Field of Application) The present invention relates to a vapor phase soldering device that performs soldering using latent heat of vaporization in the vapor phase.

(Prior Art) A conventional vapor phase soldering device has 1. As shown in FIG. 4, a liquid tank 12 is provided at the bottom of the steam tank 11, and a heat medium 13 such as a fluorine-based inert solvent is stored inside this liquid tank 12. This heat medium 13 is heated by a heater 14. It is heated and evaporated, and heat medium vapor 15 is generated inside the steam tank 11 . Using the latent heat of vaporization of the heat medium vapor 15, the cream /υ interposed between the printed wiring board P and the mounted components W is melted, and both are soldered. If the heat medium vapor 15 is left as it is, excess steam will flow from the pudding 1 to the wiring board loading port 16 and the loading port 17.
However, as the steam tank 11 rises, a cooling device such as a cooling pipe 18 is installed at the carry-in port 16 and the carry-out port 17.
Each of the cooling pipes 18 is designed to condense the excess heat medium vapor and prevent the heat medium vapor from flowing out. 19 is a competition V for transporting the printed wiring board P (problem to be solved by the invention). The heavy heat medium hot air is constantly flowing into the convection inside the hot air tank 11.
:The steam rises and is supplied to the surface of the printed wiring board P, so the steam that rises and wraps around to the center of the top surface of the printed wiring board P is influenced by the size of the printed wiring board P, heat capacity, or steam convection conditions. There is a problem of uneven heating due to a partial lack of steam in the center of the upper surface of the substrate.

The above problem becomes especially acute when processing large substrates, and there is a large difference in the steam supply conditions between the periphery of the substrate and the center of the upper surface. If the temperature is set to rise at the center of the board, the temperature at the periphery will be higher than necessary (Iffff).
This is undesirable from the viewpoint of the strength of the solder, as it promotes the generation of intermetallic compounds between the base material of the board and the solder. 5. It is also something that should be avoided from the viewpoint of deterioration over time after treatment.

An object of the present invention is to solve the problem of localized steam shortages that occur in vapor phase soldering, and to uniformize heating conditions over the entire soldering material.

[Structure of the invention]

(Means for Solving the Problems) The first aspect of the present invention is that the heat transfer liquid 22 accommodated in one part of the steam tank 21 is heated to form a vapor phase 24 in the steam tank. , a transport path 25 for the soldering object P is provided in this steam tank, and the solder attached to the soldering object U carried into the vapor phase is absorbed by the latent heat of vaporization of the vapor phase.
:The gas phase formula to be melted is /V (=In the melting device,
The steam tank 21 is located above the conveyance path 25 of the soldering object.
The object to be soldered P separately from the vapor phase 24 formed therein.
A hot air supply section 34 for locally supplying heated steam is provided on the upper surface of the heater.

Furthermore, in the second aspect of the present invention, in addition to the upper steam supply section 71, a steam nozzle 81 is provided below the conveyance path 65 for regulating the range in which the object to be soldered is exposed to the rising steam phase 64. It is.

(Function) In the first aspect of the present invention, in addition to the steam phase 24 generated from the lower part of the steam tank 21, steam is locally supplied from the upper steam supply section 34 to the parts of the soldering object P that tend to lack steam. is supplied, and the entire object to be soldered is uniformly heated by the latent heat of vaporization of the steam.

In the second aspect of the present invention, in addition to the local steam supply from the steam supply section 71 on the "-" side of the soldered object, the soldered object is supplied to the steam nozzle 81 on the lower side of the soldered object. By regulating the aeration range, the time during which the objects to be soldered are soaked in steam is kept constant, which ensures uniform solderability.

(Examples) Hereinafter, the present invention will be explained in detail with reference to each example shown in FIGS. 1 to 3.

FIG. 1 shows a first embodiment of the present invention, in which a heat transfer liquid 22 such as a fluorinated inert solvent (trade name Fluorinert) is stored in the lower part of a steam tank 21, and a heater 23 is inserted into this liquid. A vapor phase 24 evaporated and generated by the heating action of the heater 23 is formed in the steam tank 21 .

A conveyor 25 for carrying objects to be soldered is inserted into the vapor phase 24 in a direction perpendicular to the plane of the drawing, and a conveying path for objects to be soldered is provided. The object to be soldered is a printed wiring board P, and surface-mounted integrated circuit components W are mounted on the upper and lower surfaces of this board. This mounting component W is adhered to the board, and its leads are placed on paste-like cream solder applied to the board surface.

-6= Therefore, when this printed wiring board P is carried into the vapor phase 24, the solder attached to this printed wiring board P is melted by the latent heat of vaporization of the vapor phase 24. When this solder is removed from the steam tank 21, it solidifies.

In such a vapor phase soldering apparatus, a partition plate 31 is provided inside the steam tank 21, and the steam rising duct 3 is provided with a partition plate 31.
2 is partitioned. Note that the lower end of the partition plate 31 is inserted into the heat medium liquid 22 to a depth of 1 minute, and the heat medium liquid can freely flow under the partition plate 31. A horizontal duct 3 is connected to the rise of the steam upper back duct 32.
3 are continuously provided, and a steam blowing nozzle 34 as a steam supply section is provided from this horizontal duct 33 to the upper side of the conveyance path of the printed wiring board P.
5 is open 1].

A part of the steam heated by the heater 23 reaches the blow-off nozzle 34 from the rising duct 32 through the horizontal duct 33, and the steam phase 24 formed in the steam tank 21 is heated by the heater 23.
Separately, heated steam 36 is locally supplied from the air outlet 35 to the central part of the upper surface of the printed wiring board P that is not heated. heated.

FIG. 2 shows a second embodiment of the present invention, in which a heat medium liquid 42 is stored in the lower part of a steam tank 41, and this liquid is evaporated by the heating action of a heater 43 inserted into the liquid. A vapor phase 44 is formed within. A transport path 45 for a printed wiring board P as an object to be soldered is provided in this vapor phase 44 . The component W is mounted on this board via cream solder. Then, the printed wiring board P is carried into the steam tank 41 through the carry-in port 46 on one side of the steam tank 41, and is carried out via the carry-in port 47 on the other side.

A cooling pipe 48 is provided in a coil shape on the inner wall surface of the both sides/16.47, and the action of condensing and liquefying the steam in this cooling pipe prevents the vapor phase 44 in the tank from leaking to the outside. . Incidentally, such an inlet portion, an outlet portion, and their cooling pipes are also provided in the steam tank 21 shown in FIG. 1.

In such a vapor phase soldering device 1, an auxiliary steam generator 51 is disposed outside separately from the steam tank 41, and inside the steam generator 51 there is a heat medium liquid 42 and the like. A heating medium liquid 52 is contained in the liquid, and a heater 53 is placed in this liquid.
is inserted, and further a steam duct 54 is pulled out from the rise of the steam generator 51, and a steam blowing nozzle 55 as a steam supply section is provided from the duct 54 to the upper side of the conveyance path 45 of the printed wiring board P. ing. A widening outlet 56 is provided at the tip of the nozzle 55, and heated steam 57 generated in the steam generator 51 and blown out from the outlet 56 is formed in the steam tank 41. Separately from the vapor phase 44, it is locally supplied to the center of the top surface of the printed wiring board P, which is underheated, and as a result, the entire board P and mounted components W are uniformly heated.

FIG. 3 shows a third embodiment of the present invention, in which a heat medium liquid 62 is stored in the lower part of a steam tank 61, a heater 63 is inserted into this liquid, and the heat medium liquid 62 is evaporated and generated by the heating of this heater 63. A vapor phase 64 is formed in the steam tank 61;
4 is provided with a transport path 65 for a printed wiring board P as an object to be soldered.

The component W is mounted on the V-plate surface. Furthermore, similar to the one in FIG. 2, a carry-in port 66 and a carry-out port 67 are provided, and cooling pipes 68 are provided at both of these openings.

. Further, a steam pipe 71 serving as a steam supply section is disposed above the conveyance path 65 for the printed wiring board P, and a nozzle hole 72 is bored at an oblique position below the steam pipe 71. This steam pipe 71 is communicatively connected to the steam generator 51 shown in FIG. 2, etc., and receives a supply of heating steam. Then, the heated steam 73 blown out from the nozzle hole 72 is locally applied to the center of the upper surface of the printed wiring board P, which is insufficiently heated, separately from the vapor phase 64 formed in the steam tank 61. As a result, the substrate P and the mounted components W are heated uniformly as a whole.

Furthermore, a steam nozzle 81 is provided below the conveyance path 65 for the printed wiring board P to regulate the range in which the printed wiring board P is exposed to the rising vapor phase 64 . A lower part 82 of this steam nozzle 81 is formed into an enlarged skirt shape, and the heating medium liquid 6 is formed so as to cover the periphery of the heater 63.
It is inserted in 2. Similarly, a cooling pipe 83 is provided around the steam nozzle 81 for the purpose of regulating the range in which the wiring board P is exposed to the vapor phase 64.
The I pipe 83 prevents the vapor phase generated by evaporation outside the nozzle 81 from rising to the transport path.

This J: Steam blows out from the steam pipe 71 on the upper side of the sea urchin,
If the steam blowing from the lower hot air nozzle 81 is used (jf), the time (heating time) during which the upper and lower surfaces of the printed wiring board P are exposed to heated hot air is kept constant.
Uniform soldering can be ensured even on a platform with mounted components W on both sides of the printed wiring board P.

〔Effect of the invention〕

According to the present invention, a steam supply is provided that is formed in a steam tank above the conveyance path of the soldered object and locally supplies heated steam to the surface of the soldered object separately from the vapor phase. Because of the provision of a separate section, the vapor phase alone in the air tank and reaching the soldered parts can cause heating unevenness and quality variations in the center of one side of the soldered parts. Natural mood? can compensate for this, evenly heating the entire solder object (jtJ),
You can get uniform ha/vd editions.

Furthermore, in addition to the local supply from the upper steam supply section, a steam nozzle is provided at the bottom of the conveyance path to restrict the range in which the soldering object is exposed to the rising vapor phase. "The time that the beast is exposed to the steam is kept constant, and the soldering bamboo is uniformly soldered.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first practical example of a vapor phase soldering apparatus of the present invention, FIG. 2 is a sectional view showing a second embodiment thereof, and FIG. 3 is a sectional view showing a third embodiment thereof. Figure 4 is a sectional view showing a conventional gas phase type device. Tank, 22...heat medium liquid, 24...vapor phase, 25...transport route, 34...steam supply section, 36...
Heating steam, 71... Steam vibe as a steam supply section, 8
1. Steam nozzle.

Claims (2)

[Claims] (1) The heat medium liquid stored in the lower part of the steam tank is heated to form a vapor phase in the steam tank, and a conveyance path for the soldering object is provided in this vapor phase to carry it into the vapor phase. In a vapor phase soldering apparatus in which solder attached to an object to be soldered is melted by the latent heat of vaporization of the vapor phase, a vapor phase is formed in the steam tank above the conveyance path of the object to be soldered. A vapor phase soldering apparatus characterized in that a steam supply section is separately provided to locally supply heated steam to the upper surface of an object to be soldered. (2) The heat medium liquid stored in the lower part of the steam tank is heated to form a vapor phase in the steam tank, and a conveyance path for the soldering objects is provided in this vapor phase, and the objects are carried into the vapor phase. In a vapor phase soldering apparatus in which solder attached to an object to be soldered is melted by the latent heat of vaporization of the vapor phase, a vapor phase is formed in the steam tank above the conveyance path of the object to be soldered. Separately from this, a steam supply unit is provided that locally supplies heated steam to the upper surface of the object to be soldered, and a steam nozzle is provided below the conveyance path to regulate the range in which the object to be soldered is exposed to the rising steam phase. A vapor phase soldering device characterized by being provided with.