JPH0550217A - Reflow soldering device - Google Patents

Abstract

PURPOSE:To improve a temperature rise speed and uniformity of a substrate by constituting the structure so that high temperature gas for reflow blown to a substrate loaded with parts can circulate smoothly. CONSTITUTION:In an inner bottom part of a reflow furnace 11, an air blower 12 is provided, and a guide plate 13 is provided along an inner wall of one side of the reflow face from the periphery of this air blower 12. By this guide plate 13, a heater 15 is provided in an air current ascending passage 14 divided and formed in the furnace. In the upper end part of this passage 14, an inclined nozzle 16 is provided continuously. In a bottom part of the reflow furnace 11, an inert gas injecting port 17 for nitrogen gas, etc., is provided. To the substrate surface of a substrate W loaded with parts carried into the reflow furnace 11 by a conveyor 21, the inclined nozzle 16 blows high temperature gas obliquely from one side. Accordingly, the high temperature gas blown to the substrate surface, and gas which is reflected from the substrate surface and circulates to the air blower 32 do not interfere with each other but flow smoothly. By heat of the high temperature gas, solder paste of the substrate W loaded with parts is reflowed.

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 soldering a component mounting board having components mounted on the board via a solder paste by heating with a high temperature gas in a reflow furnace. ..

[0003]

2. Description of the Related Art As shown in FIG. 2 or 3, a conventional reflow soldering apparatus has
Centering 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.

Then, the component mounting board W, on which the components are mounted via the solder paste, is conveyed in a direction orthogonal to the paper surface by a conveyor (not shown), and is carried into the central portion of the furnace to be set in the furnace. After reflow soldering with high temperature gas in circulation, it is carried out from the furnace. In this conventional reflow furnace, 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 sprayed on the substrate W and the gas reflected and diffused 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.

Furthermore, 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 is Since it reflects and diffuses in four directions after hitting W,
A strong inert gas leak flow also occurs in the conveyor direction (the substrate loading port 5 in the direction orthogonal to the paper surface of FIG. 2 or FIG. 3 and the substrate loading port not shown on the opposite side), and this substrate loading port 5 and the substrate At the carry-out port (not shown), because of the narrow passage, a turbulent flow is generated by the gas flow. This causes the oxygen concentration in the furnace to rise, which causes a problem in preventing oxidation during soldering.

The present invention has been made in view of the above points, and has a structure in which high-temperature gas can smoothly move in a portion sprayed on a substrate, thereby improving the temperature rising rate and uniformity of the substrate, Further, the purpose of the inert gas atmosphere furnace is to suppress the generation of turbulent flow at the substrate loading / unloading port and prevent the increase of oxygen concentration in the furnace due to the entrainment of turbulent air into the outside air.

[Configuration of Invention]

[0009]

According to a 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 through a solder paste, and reflow soldering is performed by a high temperature gas in the reflow furnace. In the reflow soldering device to be attached, one side in the reflow furnace 11 is provided with an inclined nozzle 16 that is a direction substantially perpendicular to the substrate transfer direction and blows a high temperature gas obliquely from one side to the substrate surface. ..

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

[0011]

According to the first aspect of the present invention, the high temperature gas is made to flow in one direction by blowing the high temperature gas from the inclined nozzle 16 to the surface of the substrate obliquely from one side.
The high-temperature gas blown onto the substrate W and the high-temperature gas reflected and diffused from the substrate W flow smoothly without interfering with each other.

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

[0013]

The present invention will be described in detail below with reference to the embodiment shown in FIG.

A blower 12 is provided at the inner bottom of the reflow furnace 11,
A guide plate 13 for guiding the air flow generated by the blower 12 upward in the furnace is provided along the inner wall of the reflow furnace 11 from the periphery of the blower 12, and the guide plate 13 divides and forms the inside of the furnace. A heater 15 for heating the airflow is provided in the airflow rising passage 14.

At the upper end of the air flow rising passage 14 provided on one side in the reflow furnace 11, a direction substantially perpendicular to the conveying direction of the component mounting substrate W (direction orthogonal to the paper surface of FIG. 1) (paper surface direction). In addition, the inclined nozzle 16 that blows the high temperature gas obliquely from one side to the substrate surface is continuously provided.

A gas injection port 17 for injecting an inert gas such as nitrogen gas into the furnace is provided at the bottom of the reflow furnace 11.

The component mounting substrate W is one in which components are mounted on the substrate via solder paste, and this substrate W is reflowed from a substrate loading port 18 provided in a direction orthogonal to the plane of the reflow furnace main body. Then, the solder paste is melted by the high temperature gas in the furnace and reflow soldering is performed, and the solder paste is carried out from a substrate carry-out port (not shown) opposite to the substrate carry-in port 18.

The conveyor 21 for transporting the substrate W is provided with traveling bodies such as endless chains along a pair of left and right horizontal rails provided in a direction orthogonal to the plane of the drawing, and is projected from the traveling body. The left and right parts 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 out from the inclined nozzle 16 is blown onto the substrate W in the furnace, so that the heat of the high temperature gas causes the component mounting substrate W to be heated. Melt the solder paste and reflow solder it, and carry it out from the furnace.

Since the high temperature gas is sprayed from the inclined nozzle 16 obliquely to one side of the substrate surface, the flow of this high temperature gas is one-way, and the high temperature gas blown to the substrate surface and the blower 12 which is reflected from the substrate surface. The gas that circulates in the air flows smoothly without interfering with each other. Since the flow of the high-temperature gas becomes smooth in this way, the rate of temperature rise of the substrate W is large, 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 jetted from the inclined nozzle 16. .. That is, since a high temperature inert gas is blown from a direction substantially perpendicular to the substrate conveyance direction (direction orthogonal to the paper surface of FIG. 1) (paper surface direction) and diagonally from one side to the substrate surface, it is blown onto the substrate W. 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 (the substrate loading side and the substrate unloading side orthogonal to the paper surface of FIG. 2 or FIG. 3). Less is.

Therefore, the substrate inlet of the reflow furnace 11
Since a strong inert gas flow does not occur at 18 and the substrate outlet on the opposite side, the turbulent flow that was conventionally generated at the substrate inlet / outlet (narrow passage) does not occur, and the entrainment phenomenon of outside air due to turbulent flow Nor. Therefore, the oxygen concentration in the furnace does not rise due to the inclusion of the outside air, and the function of preventing oxidation during soldering is maintained.

[0024]

According to the first aspect of the present invention, the inclined nozzle which blows the high temperature gas on one side in the reflow furnace at a substantially right angle to the substrate transfer direction and from one side obliquely to the substrate surface. Since the high temperature gas sprayed from the inclined nozzle to the substrate surface and the gas reflected from the substrate surface do not interfere with each other, the high temperature gas can be smoothly circulated in the furnace in one direction. Therefore, the temperature rising rate and temperature uniformity of the substrate can be improved.

According to the second aspect of the present invention, a high temperature inert gas is blown onto the surface of the substrate at a substantially right angle to the substrate transfer direction, and an inert gas atmosphere furnace is provided. Therefore, the oxygen concentration in the furnace can be prevented from increasing. That is, since the inert gas flow reflected on the substrate surface does not create a strong flow in the substrate transport direction (substrate loading side and substrate unloading side), turbulent flow in the narrow substrate loading port and substrate loading port is generated. By suppressing the generation, it is possible to prevent the 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 drawings]

FIG. 1 is a cross-sectional view of a reflow soldering device showing an embodiment of the present invention.

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

FIG. 3 is a cross-sectional view showing another example of a conventional reflow soldering device.

[Explanation of symbols]

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Fujii 1-1943 Higashi Oizumi, Nerima-ku, Tokyo 1-1943 Tamura Corporation (72) Inventor Yoshinobu Abe 1-1943 Higashi Oizumi, Nerima-ku, Tokyo No. 19 Tamura Manufacturing Co., Ltd. (72) Inventor Kazuo Tono 1-1943 Higashi Oizumi, Nerima-ku, Tokyo 1-43 Tamura Manufacturing Co., Ltd. (72) Toshiya Uchida 1-1943 Higashi Oizumi, Nerima-ku, Tokyo Stock Company Tamura Factory

Claims (2)

[Claims] 1. A reflow soldering apparatus in which a substrate on which components are mounted via a solder paste is carried into a reflow furnace by a conveyor, and reflow soldering is performed by high-temperature gas in the reflow furnace. A reflow soldering device, characterized in that an inclined nozzle is provided which is substantially perpendicular to the carrying direction and which blows hot gas from one side obliquely to the substrate surface. 2. The reflow soldering device according to claim 1, wherein the high temperature gas is an inert gas.