JP3007700B2 - Reflow soldering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflow soldering apparatus for performing soldering by heating a component mounting board having components mounted on the board via a solder paste with a high-temperature gas in a reflow furnace. .

[0003]

2. Description of the Related Art As shown in FIG. 2 or FIG. 3, a conventional reflow soldering apparatus is provided inside a reflow furnace 1.
Around the blower 2, a guide plate 3 for circulating the airflow generated by the blower 2 in the furnace and a heater 4 for heating the circulating airflow are provided symmetrically.

[0004] Then, the component mounting board W, on which the components are mounted on the board via the solder paste, is transported by a conveyor (not shown) in a direction perpendicular to the plane of the paper, and is carried into the central portion of the furnace. After reflow soldering with the circulating high-temperature gas, it is carried out of the furnace. In this conventional reflow furnace, a high-temperature gas is blown from almost above the entire surface of the substrate W.

[0005]

In this conventional reflow soldering apparatus, the high-temperature gas blown to the substrate W and the gas reflected and radiated from the substrate surface interfere with each other, and the flow of the high-temperature gas is not smooth. Therefore, there is a problem that the temperature rise of the substrate W is slow and non-uniform.

Further, in an inert gas atmosphere furnace in which an inert gas such as nitrogen gas is blown into the furnace to form an inert gas atmosphere in the furnace, the inert gas blown onto the substrate W After hitting W, it is reflected and diffused in all directions,
A strong inert gas leakage flow also occurs in the conveyor direction (the substrate carrying-in portion 5 in a direction orthogonal to the paper surface of FIG. 2 or 3 and the substrate carrying-out portion (not shown) on the opposite side). At the carry-out port (not shown), turbulence occurs due to the gas flow because of the narrow passage. As a result, the phenomenon of entrainment of outside air due to the turbulent flow at the substrate carry-in port 5 and the board carry-out port. As a result, there is a problem that the oxygen concentration in the furnace rises and the prevention of oxidation during soldering is hindered.

The present invention has been made in view of the above points, and has a structure in which a high-temperature gas can smoothly move in a portion to be sprayed on a substrate, thereby improving the rate of temperature rise and uniformity of the substrate. Further, in the inert gas atmosphere furnace, it is another object of the present invention to suppress the occurrence of turbulence in the substrate loading / unloading portion and to prevent an increase in the oxygen concentration in the furnace due to turbulent air entrainment.

[Configuration of the Invention]

[0009]

According to the first aspect of the present invention, a substrate W on which components are mounted is carried into a reflow furnace 11 by a conveyor 21 via a solder paste, and reflow soldering is performed by a high-temperature gas in the reflow furnace. In the reflow soldering machine to be attached, the conveyor width in the reflow furnace 11
An inclined nozzle 16 that blows a high-temperature gas in a direction substantially perpendicular to the substrate transport direction and obliquely to one side of the substrate surface is provided on one side.

According to a second aspect of the present invention, the high temperature gas of the first aspect is an inert gas.

[0011]

According to the first aspect of the present invention , the core in the reflow furnace 11 is provided.
By blowing high-temperature gas from one side obliquely to the substrate surface from the inclined nozzle 16 provided on one side in the conveyor width direction ,
Since the flow of the high-temperature gas is one-way, the high-temperature gas blown to the substrate W and the high-temperature gas reflected and radiated from the substrate W flow smoothly without mutual interference. further,
Substantially perpendicular to the board transfer direction and the board surface
The high-temperature gas is blown from one side diagonally to
High-temperature gas reflected from the substrate is attached around the conveyor.
Circulates inside the furnace as if swirling and flows toward the conveyor
Less.

According to the second aspect of the present invention, since a high-temperature inert gas is blown from a direction substantially perpendicular to the substrate transfer direction and obliquely to one side of the substrate surface, the inert gas reflected from the substrate W is blown. Circulates in the furnace so as to rotate around the conveyor 21 and rarely flows to the substrate loading side and the substrate loading side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to an embodiment shown in FIG.

A blower 12 is provided at the inner bottom of the reflow furnace 11,
A guide plate 13 is provided along the inner wall on one side of the reflow furnace 11 from around the blower 12 to guide an airflow generated by the blower 12 upward in the furnace, and the guide plate 13 is formed inside the furnace by the guide plate 13. A heater 15 for heating the airflow is provided in the airflow rising passage 14.

At the upper end of the airflow ascending passage 14 provided on one side of the reflow furnace 11, a direction substantially perpendicular to the direction in which the component mounting board W is transported (the direction perpendicular to the plane of FIG. 1) is shown. In addition, an inclined nozzle 16 for blowing high-temperature gas from one side obliquely to the substrate surface is continuously provided.

At the bottom of the reflow furnace 11, a gas inlet 17 for injecting an inert gas such as nitrogen gas into the furnace is provided.

The component mounting board W has components mounted on the board via solder paste. The board W is transferred from a board loading / unloading portion 18 provided in a direction perpendicular to the sheet of FIG. Then, the solder paste is melted by the high-temperature gas in the furnace, and reflow soldering is performed. Then, the solder paste is carried out from a board outlet (not shown) opposite to the board inlet 18 to the outside.

The conveyor 21 for transporting the substrate W is provided with a revolving body such as an endless chain along a pair of left and right horizontal rails provided in a direction perpendicular to the paper surface, and is protruded from the revolving body. The right and left portions of the substrate W are locked by the pins 22 and transported.

Next, the operation of the embodiment shown in FIG. 1 will be described.

The component mounting substrate W is carried into the reflow furnace 11 by the conveyor 21 and the high temperature gas blown from the inclined nozzle 16 is blown onto the substrate W in the furnace. Is melted and soldered by reflow soldering, and then carried out of the furnace.

Since the high-temperature gas is blown from the inclined nozzle 16 obliquely to the substrate surface, the flow of the high-temperature gas is one-way, and the high-temperature gas blown to the substrate surface and the blower 12 The gas circulating smoothly flows without interfering with each other. Since the flow of the high-temperature gas is smooth, the temperature of the substrate W is increased at a high rate, and the entire surface of the substrate is uniformly heated.

When an inert gas such as nitrogen gas is injected into the furnace from the gas inlet 17 to form an inert gas atmosphere in the furnace, a high-temperature inert gas is ejected from the inclined nozzle 16. . That is, a high-temperature inert gas is blown from a direction substantially perpendicular to the substrate transport direction (a direction perpendicular to the paper surface of FIG. 1) (paper surface direction) and obliquely to one side of the substrate surface. The inert gas reflected from the substrate W circulates in the furnace so as to swirl around the conveyor 21 and flows in the conveyor direction (substrate loading side and substrate unloading side orthogonal to the plane of FIG. 2 or FIG. 3). Less is.

Therefore, the substrate loading port of the reflow furnace 11
Since no strong inert gas flow is generated at the substrate loading / unloading portion 18 and the opposite side, the turbulent flow that occurred conventionally at the substrate loading / unloading portion (narrow passage) does not occur, and the outside air is trapped by the turbulent flow. Nor. Therefore, the oxygen concentration in the furnace does not increase due to the entrainment of the outside air, and the oxidation preventing function at the time of soldering is maintained.

[0024]

According to the first aspect of the present invention, a high-temperature gas is applied to one side of the width direction of the conveyor in the reflow furnace in a direction substantially perpendicular to the substrate transport direction and obliquely to one side of the substrate surface. Since the inclined nozzle to be sprayed is provided, the high-temperature gas blown from the inclined nozzle to the substrate surface and the gas reflected from the substrate surface can be smoothly circulated in the furnace in one direction without mutual interference. For this reason, the rate of temperature rise and temperature uniformity of the substrate can be improved. In addition,
The direction is almost perpendicular to the feeding direction, and
Since high-temperature gas is blown from one side diagonally,
High-temperature gas reflected from the substrate swirls around the conveyor
Circulate in the furnace so that it flows in the direction of the conveyor
Because of the small number, the substrate loading port of the reflow furnace and the opposite side
No turbulence is generated at the substrate exit, and
Can be prevented.

According to the second aspect of the present invention, a high-temperature inert gas is blown obliquely to the substrate surface in a direction substantially perpendicular to the substrate transfer direction and obliquely to the substrate surface. Thus, an increase in the oxygen concentration in the furnace can be prevented. In other words, the inert gas flow reflected on the substrate surface does not create a strong flow toward the substrate transport direction (substrate loading side and substrate transport side), so that the turbulent flow at the narrow substrate loading portion and the substrate loading portion is reduced. By suppressing the generation, it is possible to prevent an increase in the oxygen concentration in the furnace due to the entrainment of outside air into the furnace due to the turbulent flow.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reflow soldering apparatus showing one embodiment of the present invention.

FIG. 2 is a sectional view showing an example of a conventional reflow soldering apparatus.

FIG. 3 is a sectional view showing another example of a conventional reflow soldering apparatus.

[Explanation of symbols]

 W Component mounting board 11 Reflow furnace 16 Inclined nozzle 21 Conveyor

Continuing from the front page (72) Inventor Mamoru Fujii 1-19-43 Higashi-Oizumi, Nerima-ku, Tokyo Inside the Tamura Corporation (72) Inventor Kannobu Abe 1-19-143, Higashi-Oizumi, Nerima-ku, Tokyo Inside the Tamura Plant (72) Inventor Kazuo Tono 1-19-143 Higashi-Oizumi, Nerima-ku, Tokyo, Japan Stock Inside the Tamura Plant (72) Inventor Toshiya Uchida 1-19-143, Higashi-Oizumi, Nerima-ku, Tokyo (56) References JP-A-1-148459 (JP, A) JP-A-61-289697 (JP, A) JP-A-59-220282 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) B23K 1/008 H05K 3/34 507

Claims (2)

(57) [Claims] 1. A is carried into the reflow furnace by a substrate mounted components via a solder paste conveyor, in the reflow soldering apparatus for reflow soldering by hot gas in the reflow furnace, the conveyor width direction of the reflow furnace A reflow soldering apparatus, wherein an inclined nozzle which blows a high-temperature gas from one side obliquely with respect to the substrate surface in a direction substantially perpendicular to the substrate transport direction is provided on one side. 2. The reflow soldering apparatus according to claim 1, wherein the high-temperature gas is an inert gas.