JPS63115677A - Gaseous phase type soldering device - Google Patents

Abstract

PURPOSE:To prevent a temperature drop at the time carrying a pre-heated work into a vapor phase, by providing a carrying-in port part heater between a cooling part provided on a work carrying-in port part and a work carrying path, in a vapor tank of a gaseous phase type soldering device. CONSTITUTION:A soldering device forms a saturated vapor phase 15 in the inside of a vapor tank 11, and executes reflow soldering to works 17, 18 which are pre-heated by a pe-heater of the outside, in a carrying path extending from a carrying-in port part 21 to a carrying-out port part 22. In such a case, by a condensing action of cooling parts 23, 24 provided on the carrying-in port part 21 and the carrying-out port part 22, it is prevented that the vapor phase 15 leaks out to the outside. Also, by a carrying-in port part heater 31 provided between the cooling part 23 and a work carrying path, the works 17, 18 are protected from a cooling action of the cooling part 23. In such a way, a temperature fall at the time when the work which is pre-heated by the outside is carried into the vapor phase can be prevented.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to a vapor-phase soldering method in which the preheating effect provided by an external preheater can be maintained up to the saturated vapor phase in a steam tank. This is related to the a position.

(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 and evaporated by a heater 14. As a result, a fluorine-based inert saturated vapor phase 15 is formed inside the steam tank 11, and the latent heat of vaporization of this saturated vapor phase 15 causes a printed wiring board as a workpiece to be carried into the steam tank 11 by a conveyor 16. The paste solder (cream solder) between the component 17 and the mounted component 18 is reflowed, and the component 18 is reflow soldered onto 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, a workpiece loading port 21 is provided on one side of the steam tank 11, and a workpiece loading port 22 is provided on the other side.
A cooling section 23.24 such as a water-cooled cooling coil is disposed at the loading inlet section 21 and the unloading outlet section 22, and this cooling section 23.2
4 cools the inside of the carry-in port 21 and the carry-out port 22, thereby limiting the region of the saturated vapor phase 15, and causing the vapor to float around the saturated vapor phase 15 and try to leak to the outside. Most of the fluorine-based inert vapor mist is condensed and liquefied, and collected in the liquid reservoir 12.

On the other hand, a pre-heater 25 is arranged outside the work entry port 21 of the steam tank 11, and the pre-heater 25 preheats the works 17 and 18 so as to approach the temperature of the saturated vapor phase 15 as much as possible. .

(Problem to be Solved by the Invention) However, since the cooling section 23 is provided between the external pre-heater 25 and the saturated vapor phase 15, the workpieces 17 and 18 heated by the pre-heater 25 are The temperature decreases due to the cooling effect of the section 23, and the function of the pre-heater 25 is not utilized for one minute.

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 a sub-heater 2 provided outside the steam tank 11.
The workpieces 17 and 18 preheated by the steam tank 1
1, the workpiece is inserted into the saturated vapor phase 15 formed inside the steam tank 11 while being transported from the workpiece inlet 21 to the workpiece outlet 22, and reflow soldering is performed by the latent heat of vaporization of this saturated vapor phase 15. cooling section 23 provided at the workpiece loading port 21 and the workpiece loading port 22.
．． In a vapor phase soldering apparatus in which leakage of steam inside the tank to the outside is prevented by the condensation action of 24, a loading port heater is provided between the cooling section 23 provided at the workpiece loading port 21 and the workpiece conveyance path. 31 are arranged.

(Function) In the present invention, the workpieces 17 and 18 preheated by the pre-heater 25 are protected from the cooling effect of the cooling unit 23 by the inlet heater 31 when being carried into the steam 4fi11, and are saturated at least without temperature drop. It is inserted into the vapor phase 15. On the other hand, the steam in the tank is condensed under the cooling effect of the cooling parts 23 and 24, and does not leak out to the outside of the steam tank 11.

(Example) The present invention will now be described in detail with reference to a practical example shown in FIGS. 1 and 2. Note that the same parts as in the conventional example shown in FIG. 3 are given the same reference numerals, and their explanation 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 configuration in which a thin heat generating plate is sandwiched between a pair of silicone rubber.

FIG. 2 shows the temperature profile of this vapor-phase soldering apparatus.
(p At the workpiece entrance section 21, the workpiece heated by the pre-heater 25 is prevented from decreasing in temperature by the action of the entrance section heater 31, (C) and the workpiece 17.1
8 is inserted into the saturated vapor phase 15, the temperature of the workpiece is rapidly raised to 215°C, and reflow soldering is performed. The workpiece temperature begins to drop.

On the other hand, the saturated vapor phase 15 in the steam 1fi11 and the fluorine-based inert vapor mist floating around it are condensed by the cooling action of the cooling section 23, 24 and do not leak out of the tank.

In this embodiment, the workpiece temperature is prevented from dropping by the loading entrance heater 31, but in the present invention, the workpiece temperature may be increased by the loading entrance heater 31.

〔Effect of the invention〕

According to the present invention, since the loading entrance heater is disposed between the cooling section of the workpiece loading entrance and the workpiece conveyance path, the loading entrance heater allows the workpiece preheated by the external pre-heater to enter the saturated vapor phase. The cooling effect received from the cooling unit is blocked when the workpiece is transported into the workpiece, effectively preventing the workpiece from dropping in temperature, which leads to improved soldering characteristics in the saturated vapor phase.

[Brief explanation of the drawing]

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 sectional view of a conventional vapor phase soldering device. It is. 11...Steam tank, 15...Saturated vapor phase, 17.18...
Workpiece, 21...Workpiece loading port, 22...Workpiece loading port, 23.24...Cooling unit, 25...Preheater, 3
1. Heater at loading entrance.

Claims (1)

[Claims] (1) Saturated steam is formed inside the steam tank while the workpiece, which has been preheated by a preheater installed outside the steam tank, is 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 in which leakage is prevented, characterized in that a carry-in port heater is disposed between a cooling section provided at the workpiece carry-in port and a work transfer path. attaching device.