JPH0220352B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a vapor phase soldering method that can maintain the preheating effect provided by an external preheater up to the saturated vapor phase in a steam tank. The present invention relates to a mounting device.

(Prior Art) As shown in FIG. 3, in a vapor phase soldering apparatus, a fluorine-based inert solvent 13 contained in a liquid reservoir 12 at the bottom of a steam tank 11 is heated by a heater 14. A fluorine-based inert saturated vapor phase 15 is formed inside the steam tank 11 by being evaporated.
The latent heat of vaporization of this saturated vapor phase 15 reflows the paste solder (cream solder) between the printed wiring board 17 as a workpiece carried into the steam tank 11 by the conveyor 16 and its column-mounted components 18. , the component 18 is reflow soldered to the board 17.

The fluorine-based inert solvent 13 used in such vapor phase soldering equipment is expensive, and leakage of the fluorine-based inert vapor to the outside of the steam tank 11 must be prevented as much as possible. It won't happen.

Therefore, the workpiece loading port 2 is placed on one side of the steam tank 11.
1 is provided, and a workpiece unloading port 2 is provided on the other side.
2 is provided, and its loading inlet 21 and unloading outlet 22 are provided.
Cooling sections 23 and 24 such as water-cooled cooling coils are disposed in the two parts, and the saturated vapor phase 15 is cooled by the cooling sections 23 and 24 into the loading port 21 and the loading port 22. Most of the fluorine-based inert vapor mist that floats around the saturated vapor phase 15 and tends to leak outside is condensed and liquefied, and collected in the liquid reservoir 12.

On the other hand, a preheater 25 is arranged outside the workpiece loading port 21 of the steam tank 11, and the workpieces 17 and 18 are preheated by the preheater 25 so as to approach the temperature of the saturated vapor phase 15 as much as possible. ing.

(Problem to be Solved by the Invention) However, since the cooling section 23 is provided between the external preheater 25 and the saturated vapor phase 15, the works 17 and 18 heated by the preheater 25 The temperature decreases due to the cooling action of the cooling section 23, and the function of the preheater 25 is not fully utilized.

Incidentally, since the cooling section 23 is necessary to prevent the steam inside the tank from leaking to the outside, there is no choice but to provide it.

An object of the present invention is to prevent a temperature drop when a workpiece preheated by an external preheater is introduced into the saturated vapor phase.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides workpieces 17 and 1 that are preheated by a preheater 25 provided outside the steam tank 11.
8 is inserted into the saturated vapor phase 15 formed inside the steam tank 11 while being transported from the workpiece loading port 21 to the workpiece loading port 22 of the steam tank 11,
Reflow soldering is performed by the latent heat of vaporization of this saturated vapor phase 15, and the cooling section 2 provided at the workpiece loading port 21 and the workpiece loading port 22
In a vapor phase soldering apparatus in which leakage of the steam inside the tank to the outside is prevented by the condensation action of 3 and 24, there is a space between the cooling section 23 provided at the workpiece loading port 21 and the workpiece conveyance path. Loading entrance heater 3
1 has been deployed.

(Function) According to the present invention, the works 17 and 18 preheated by the preheater 25 are protected from the cooling action of the cooling unit 23 by the entrance heater 31 when being carried into the steam tank 11, so that the It is inserted into the saturated vapor phase 15 without descending. On the other hand, the steam in the tank is condensed under the cooling effect of the cooling units 23 and 24, and does not leak to the outside of the steam tank 11.

(Example) Hereinafter, the present invention will be described in detail with reference to an example shown in FIGS. 1 and 2. In addition, the third
The same parts as those of the conventional example shown in the figures are given the same reference numerals, and the explanation thereof will be omitted.

A loading port heater 31 is disposed between a cooling unit 23 provided at the workpiece loading port 21 and the workpiece conveyance path. The loading port heater 31 is a rubber heater arranged at the upper and lower sides of the rectangular cylinder 32, respectively, corresponding to the cooling units 23 provided at the upper and lower sides of the workpiece conveyance path.

This rubber heater has a sandwich structure in which a thin heating plate is sandwiched between a pair of silicone rubber.

FIG. 2 shows the temperature profile of this vapor phase soldering apparatus, in which (A) the preheater 25
As a result, the temperature of the works 17 and 18 rises to approximately 150° C.; (B) At the work entrance section 21, the temperature of the work heated by the preheater 25 decreases due to the action of the entrance heater 31; (C) and the works 17 and 18 are in the saturated vapor phase 15
When the workpiece is inserted into the workpiece, the temperature of the workpiece is rapidly raised to 215°C, and reflow soldering is performed. Start.

On the other hand, the saturated vapor phase 15 in the steam tank 11 and the fluorine-based inert vapor mist floating around it are condensed under the cooling action of the cooling units 23 and 24, and do not leak out of the tank.

Note that in this embodiment, the workpiece temperature is prevented from decreasing by the loading entrance heater 31;
In the present invention, the temperature of the workpiece may be increased by the loading port heater 31.

〔Effect of the invention〕

According to the present invention, since the loading entrance heater is disposed between the cooling unit at the workpiece loading entrance and the workpiece conveyance path, the loading entrance heater saturates the workpiece that has been preheated by the external preheater. When transported into the vapor phase, the cooling effect received from the cooling section is blocked,
The temperature drop of the workpiece is effectively prevented, which leads to improved soldering properties in the saturated vapor phase.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the vapor phase soldering device of the present invention, Fig. 2 is a graph showing the temperature profile of the device, and Fig. 3 is a cross section of a conventional vapor phase soldering device. It is a diagram. 11... Steam tank, 15... Saturated vapor phase, 17,
18...Workpiece, 21...Workpiece entrance section, 22
...Workpiece unloading port, 23, 24...Cooling section, 2
5... Preheater, 31... Inlet heater.

Claims (1)

[Claims] 1. The workpiece, which has been preheated by a preheater installed outside the steam tank, is transported into the saturated vapor phase formed inside the steam tank while being transported from the workpiece loading port to the workpiece loading port of the steam tank. reflow soldering is performed by the latent heat of vaporization of this saturated vapor phase, and the steam in the tank is transferred to the outside by the condensing action of the cooling section provided at the workpiece loading port and workpiece loading port. A vapor phase soldering apparatus that prevents leakage, characterized in that an entrance heater is disposed between a cooling section provided at the workpiece entrance and a workpiece conveyance path. attaching device.