JPH0763840B2 - Vapor soldering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a vapor-phase soldering apparatus capable of optimally controlling a temperature profile of an object to be soldered.

(Prior Art) In the conventional vapor-phase soldering apparatus, as shown in FIG. 3, a liquid tank portion 12 is integrally provided in a lower portion of a steam tank 11 and is housed inside the liquid tank portion 12. Liquid (fluorine-based inert solvent)
By evaporating 13 by the heater 14, a vapor phase 15 is formed in the vapor tank 11, and an object to be soldered from a carry-in port 16 provided on one side of the vapor tank 11 with respect to the vapor phase 15. The printed wiring board 17 as the above is carried in by the conveyor 17a, and the board-mounted component is reflow-soldered to the board 17 by the latent heat of vaporization that the vapor phase 15 has, and the carry-out portion provided on the other side of the steam tank 11 The substrate 17 is carried out via 18.

In such a vapor phase soldering apparatus, conventionally, a cooling coil 19 is provided inside the carry-in port 16 and the carry-out port 18, and the vapor phase 15 is provided by the condensing action of the cooling coil 19.
Are prevented from leaking to the outside. The cooling coil 19 alone does not completely prevent the steam from leaking out, so that a liquid recovery system 21 as shown in FIG. 3 is provided.

The liquid recovery system 21 sucks steam into the condensation tank 23 from the vicinity of the openings of the carry-in part 16 and the carry-out part 18 through a steam introducing pipe 22, and condenses the steam into a condenser coil (evaporator in the refrigeration cycle). The air condensed and liquefied by 24, and the air whose liquid content has been removed by the condensing coil 24 is forcedly exhausted to the outside by the fan 26 via the exhaust pipe 25. Then, the liquid 13a dropped from the condensing coil 24 and accumulated in the tank 23 is stored in the pump 2
The liquid is circulated and supplied to the liquid tank portion 12 via the liquid supply pipe 28 by 7.

(Problems to be Solved by the Invention) As described above, in the conventional vapor-phase soldering apparatus, the cooling coil for vapor condensation is provided inside the carry-in port 16 and the carry-out port 18.
19 is provided, the printed wiring board 17 preheated by an external heater (not shown)
When it enters, it is cooled by the cooling coil 19 and the second
As shown by the chain double-dashed line in the figure, the temperature of the printed wiring board is lowered and the preheating effect is weakened. Therefore, there is a possibility that reflow soldering in the steam tank 11 may not be performed well.

An object of the present invention is to obtain an optimum temperature profile of the soldering object by preventing the temperature drop of the soldering object at the carry-in port in the vapor phase soldering device.

[Structure of Invention]

(Means for Solving Problems) The first aspect of the present invention relates to a liquid stored in the liquid tank portion 12 of the steam tank 11.
13 is evaporated to form a vapor phase 15 in the vapor tank 11, and a carry-in port portion 16 provided on one side of the vapor tank 11 in the vapor phase 15
The soldering object 17 is carried in from and reflow soldering is performed by the latent heat of vaporization of the vapor phase 15, and the vapor tank
In the vapor-phase soldering device for carrying out the soldering object 17 from the carry-out portion 18 provided on the other side to the outside 11, the soldering subject consisting of the carry-in portion 16, the steam tank 11 and the carry-out portion 18 A vapor condensing section 34 drawn from the vapor tank 11 via a vapor guide section 33 is provided outside the article transport line.

The second aspect of the present invention is, in addition to the configuration of the first aspect of the present invention, a preheated part to be soldered inside the carry-in port 16.
31 is provided, and the soldering object cooling part 32 is provided inside the carry-out part 18.

(Operation) The present invention has the steam condensing section 34 outside the carry-in section 16, so that the soldered object 17 carried into the steam tank 11 does not have a risk of being cooled by the steam condensing section 34. There is no risk of temperature drop.

Furthermore, the temperature of the object to be soldered 17 immediately before soldering is raised by the object to be soldered preheating section 31 provided at the carry-in section 16, and the object to be soldered cooling section 32 provided at the carry-out section 18 is provided. Then, the object to be soldered 17 after soldering is forcibly cooled.

(Example) Hereinafter, the present invention will be described in detail with reference to an example shown in FIG. The same parts as those of the conventional vapor phase soldering apparatus and the liquid recovery system shown in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted.

An electric heater 31 as a preheating portion for an object to be soldered is provided inside the carry-in section 16, and a cooling section 32 for an object to be soldered is provided inside the carry-out section 18. The cooling unit 32 is a shower unit that receives the supply of liquid nitrogen, and takes heat of vaporization from the surroundings when the liquid nitrogen vaporizes, so that the property is utilized to obtain the rapid cooling effect. Since this nitrogen is an inert gas, it has an antioxidant effect like the vapor phase 15.

Furthermore, the steam guide from the steam tank 11 is provided outside the transfer line for the soldered object, which is composed of the carry-in section 16, the steam tank 11 and the carry-out section 18, and both sides of the carry-in side and the carry-out side of the steam tank 11. A vapor condensing unit 34 drawn out via the unit 33 is provided.
Since the steam introducing pipe 22 is connected to the steam condensing unit 34, the intake action of the fan 26 is
Up to 34, the vapor phase 15 in the vapor tank 11 is forcibly sucked into the vapor condensing portion 34 via the vapor guide portion 33.

A cooling coil 35 is provided inside the vapor condensing unit 34,
The liquid condensed by the cooling coil 35 is the vapor condensing unit.
The lower portion of the inclined bottom surface of 34 is directly returned to the liquid tank section 12 by a liquid return pipe 36 communicating with the steam tank 11. Further, the steam that has passed through the cooling coil 35 is the steam introduction pipe.
It is sucked into the condensing tank 23 via 22 and is condensed in the tank 23.

Further, by connecting the liquid supply pipe 28 to the high part of the inclined bottom surface of the vapor condensing part 34, the low temperature liquid 13a in the tank 23 flows to the high temperature when it flows down the inclined bottom surface of the vapor condensing part 34. Make arrangements so that the temperature rises by receiving heat from the inclined bottom surface of. As a result, the liquid circulated from the condensing tank 23 through the vapor condensing unit 34 and the liquid return pipe 36 to the liquid tank unit 12 has a sufficiently high temperature, so that the liquid in the liquid tank unit 12 that affects the vapor phase level is Never lower the temperature.

Then, as shown by the solid line in FIG. 2, the printed wiring board 17 as the object to be soldered has a heating action of the heater 31 provided inside the carry-in port portion 16 without an external heater. In response to this, the temperature rises rapidly to the required preheating temperature of 150 ° C, and when it is inserted into the vapor phase 15 in the vapor tank 11, the latent heat of vaporization released from the vapor when the vapor condenses on the substrate surface. The temperature is raised to 215 ° C. by this, the cream solder on the board surface is melted, and the board mounted component is soldered to the board surface. Further, the substrate 17 after the reflow soldering is subjected to the quenching action by the nitrogen gas at the carry-out port portion 18, and the temperature thereof is rapidly lowered.

〔The invention's effect〕

According to the present invention, since the vapor condensing part drawn out from the vapor tank via the vapor guide part is provided outside the soldered object transfer line consisting of the carry-in part, the steam tank and the carry-out part, The temperature drop of the soldered object can be prevented, and the object to be soldered heated to a predetermined temperature can be inserted inside the vapor phase to obtain good reflow soldering.

Further, according to the present invention, since the preheated portion to be soldered is provided inside the carry-in portion and the cooling portion to be soldered is provided inside the carry-out portion, the preheated portion provided close to the vapor phase is provided. An optimum temperature profile of the object to be soldered can be obtained by the heating section and the cooling section. Furthermore, since the pre-heating unit and the cooling unit are incorporated inside the loading / unloading unit, there is no need for an external heater or an external cooling fan as in the conventional case, and the apparatus can be made compact.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a vapor phase soldering device of the present invention, FIG. 2 is a graph comparing temperature profiles of objects to be soldered by the device of the present invention and a conventional device, and FIG. 3 is a cross-sectional view of the vapor phase soldering device of FIG. 11 …… Steam tank, 12 …… Liquid tank section, 13 …… Liquid, 15 …… Steam phase, 16 …… Inlet section, 17 …… Printed wiring board as soldered object, 18 …… Outlet section , 31 …… Heater as a preheating part for soldering object, 32 …… Cooling part for soldering object, 33 …… Steam guiding part, 34 …… Steam condensing part.

Claims (2)

[Claims] Claim: What is claimed is: 1. A liquid contained in a liquid tank of a steam tank is vaporized to form a vapor phase in the steam tank, and a soldered material is introduced into the vapor phase from a carry-in port provided on one side of the steam tank. In a vapor phase soldering device that carries in a soldering object and performs reflow soldering by latent heat of vaporization of the vapor phase, and carries out the soldered object to the outside from a carry-out port provided on the other side of the steam tank. , Vapor phase soldering characterized in that a vapor condensing section drawn out from the vapor tank via a vapor guide section is provided outside a soldering object transfer line consisting of the carry-in section, a steam tank and a carry-out section. apparatus. 2. A liquid contained in a liquid tank portion of the steam tank is evaporated to form a vapor phase in the steam tank, and the soldered material is introduced into the vapor phase from a carry-in portion provided at one side of the steam tank. In a vapor phase soldering device that carries in a soldering object and performs reflow soldering by the latent heat of vaporization of the vapor phase, and carries out the soldered object from the carry-out port portion provided on the other side of the steam tank to the outside. , A preheated part to be soldered is provided inside the carry-in part, a cooling part to be soldered is provided inside the carry-out part, and the soldered part comprising the carry-in part, the steam tank and the carry-out part A vapor-phase soldering device, characterized in that a vapor condensing portion is provided outside the article transfer line through the vapor guiding portion from the vapor tank.