JPH05203363A - Feeding device for high temperature gas in reflow atmosphere furnace - Google Patents

Abstract

PURPOSE:To generate high temperature atmosphere gas without needing heating gas for an exclusive use by a method wherein a conduit through which atmosphere gas is caused to flow is installed in a state to extend through preliminary heating chambers and high temperature atmosphere gas is generated, in a reflow atmosphere furnace having the preliminary heating chambers and the main heating chamber. CONSTITUTION:In a reflow atmosphere furnace, a printed wiring substrate on which an electronic chip part being a substance to be processed is mounted is placed on a beam, through feed movement of the beam, the substrate is caused to pass, in order, preliminary heating chambers 2 and 3, a main heating chamber 4, and a cooling chamber 5, and by melting solder, the chip part is mounted. In this case, a conduit 20 formed of a heat resisting member is disposed in a manner to extend through the upper parts of the right corners of the preliminary heating chambers 2 and 3, and the inner end side of a furnace is opened to the main heating chamber 4 to form an injection port 21. During operation of a furnace, high pressure gas in a gas cylinder is reduced by means of a pressure regulating valve to produce a very low temperature low pressure gas, which is introduced to the conduit 20. The very low temperature low pressure gas is heated by the preliminary heating chambers 2 and 3 to produce high temperature atmosphere gas, which is fed to the main heating chamber 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention applies an electronic chip component such as an IC to a printed wiring board with a solder paste,
Device related to a surface-mounting reflow furnace that mounts electronic chip parts, etc. on it and melts solder to mount the chip parts, etc., in particular, a device that preheats and supplies the atmospheric gas supplied to the main heating chamber Regarding

[0002]

2. Description of the Related Art In the surface mounting method, a paste (solder) is applied on the surface of a printed circuit board (PCB) by screen printing or the like, electronic chip components are mounted, and the solder is melted and soldered in a continuous furnace. The process of melting solder and soldering in this continuous furnace is called a reflow process, and the furnace is called a reflow furnace. A furnace in which an inert gas or the like is supplied to the reflow furnace and the reflow soldering in the previous period is performed in an atmosphere of the inert gas or the like is called a reflow atmosphere furnace.
FIG. 2 is a perspective view of a main part of a conventional atmosphere furnace for performing surface mounting soldering. In the figure, 1 is provided with a pre-heating chamber 1 (2), a pre-heating chamber 2 (3), a main heating chamber (4), and a cooling chamber (5) continuously in a line, and carries in and out the PCB of the processing object. In order to do so, a door (9) is provided at the lower part of the side surface of each chamber, and, for example, two parallel beams (8) are provided at the bottom of the lower side of the door from the preheating chamber 1 (2) for cooling. It is provided through the chamber (5), the inlet 1 (6) is provided on the side surface of the main heating chamber (4), and further, from the preheating chamber 1 (2) to the bottom surface of the main heating chamber (4). It is an atmosphere furnace including a panel heater 1 (41), a panel heater 2 (42), and a panel heater 3 (43). Reference numeral 7 is a pipe connected to the inlet 1 (6) on one side and to the pressure regulating valve side on the other side. Reference numeral 10 indicates the PCB loading direction of the object to be processed.

The operation will be described. A PCB on which an electronic chip component of the object to be processed is mounted is placed on the beam (8) and lifted in the air by the upward movement of the beam (8), and then the leftward movement of the beam (8). Thus, for example, the PCB moves from the preheating chamber 1 (2) to the preheating chamber 2 (3). Furthermore, the beam (8)
The downward movement of the PCB causes the preheating chamber 2
It is placed on the panel heater 2 (42) of (3). Also,
The right movement of the beam (8) returns it to its initial state,
Complete one cycle of exercise. By the series of continuous movements of the beam (8), the object to be processed is carried in and carried out. The door (9) is open during the continuous movement of the beam (8), and is controlled so as not to hinder the carry-in. In the preheating chamber 1 (2), the object to be processed is preheated for reflow soldering. When a preset time elapses, the door (9) is opened, the continuous movement of the beam (8) is started, and the PCB is carried into the preheating chamber 2 (3) from the preheating chamber 1 (2). , Where it is further subjected to a second stage of preheating. When a preset time has passed, the PCB is carried into the main heating chamber (4) and subjected to main heating at an appropriate temperature and an appropriate time for reflow soldering, and at the same time, from the inlet 1 (6), atmospheric gas, For example, nitrogen gas is supplied so as to have a predetermined pressure. Next, the PCB is carried into the cooling chamber (5), subjected to the first cooling, and finally carried out of the furnace and cooled at room temperature. The conventional method for supplying gas to an atmospheric furnace is to supply gas from a high-pressure gas cylinder to a main heating chamber (4) where the gas is depressurized to a predetermined pressure with a pressure regulator and main heating is performed from the inlet 1 (6) at a low temperature. Was. For this reason, the PCB, the electronic chip parts, and the like placed in the place where the low-temperature gas is directly blown are partially cooled, and the heat distribution may not be uniform in the main heating. Therefore, the solder paste is unevenly melted, and voids are formed in the soldered portion, and the surface is not glossy.

[0004]

DISCLOSURE OF THE INVENTION The present invention is a reflow atmosphere furnace in which an atmosphere gas in a preheated state is supplied to a main heating chamber for reflow soldering, which is inexpensive, does not require a dedicated heating device, and is high in cost. An object is to provide a temperature atmosphere gas supply device.

[0005]

In order to achieve the above object, a conduit such as a pipe for supplying the gas whose pressure has been adjusted is provided as a heat exchanger so as to pass through the preheating chamber.

[0006]

With the above-mentioned structure, the high-pressure gas in the high-pressure gas cylinder is depressurized to a predetermined pressure by the pressure regulating valve, and the low-pressure and low-temperature gas obtained is passed through a pipe such as a pipe installed in the preheating chamber. It is heated while passing and is sufficiently warmed up to the main heating chamber, and a gas of an appropriate temperature can be supplied in the main heating chamber.

[0007]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view of a main part of a high-temperature gas supply device in a reflow atmosphere furnace according to the present invention. 20 is 1
One side is connected to the pressure regulating valve side, the other side is connected to the inlet 2 (21) of the main heating chamber, and it is a conduit made of a heat resistant member installed so as to pass through the upper right corner of the preheating chambers (2) and (3) is there. Reference numeral 30 denotes an inflow of low-temperature gas whose pressure is reduced by a pressure regulating valve and adjusted to a low pressure. Reference numeral 31 denotes a gas flow that is gradually heated while passing through the preheating chambers (2) and (3). Reference numeral 32 represents the inflow of the heated gas supplied from the inlet (21) to the main heating chamber.

The operation will be described. High-pressure gas such as a gas cylinder is adiabatically expanded by reducing the pressure to a predetermined pressure with a pressure regulating valve, and becomes a low-pressure gas having an extremely low temperature. This extremely low temperature gas is heated in the part of the preheating chamber while passing through the conduit (20), becomes a high temperature gas, and is supplied to the main heating chamber. still,
The conduit (20) is such that the part of the preheating chamber functions as a heat exchanger, and the shape and position of the arrangement may be other than those of the present embodiment. For example, two conduits of a heat-resistant member having a quadrangular cross-sectional shape may be installed in the upper right corner and the upper left corner, and gas may be supplied to the main heating chamber from two inlets. Further, a hollow box-shaped conduit may be provided outside the side surfaces of the preheating chamber and the main heating chamber, and the heat exchanger may be used to heat the gas.

[0009]

EFFECTS OF THE INVENTION Since a pipe such as a pipe for heat exchange for flowing the atmospheric gas is provided in the vicinity of the preheating chamber and a heat source for heating the atmospheric gas is obtained from the preheating chamber or the like, there is no need to provide a dedicated heat source. Atmosphere gas at an appropriate temperature can be supplied to the main heating chamber. Therefore, since the PCB and the chip parts can be kept in a state of uniform temperature distribution, optimal reflow soldering can be performed, which contributes to maintaining the quality of the product, and the cost of the product can be reduced, and the market can be expected to expand.

[Brief description of drawings]

FIG. 1 is a perspective view of essential parts of a high-temperature gas supply device in a reflow atmosphere furnace according to the present invention.

FIG. 2 is a perspective view of an essential part of a conventional reflow atmosphere furnace for surface mounting soldering.

[Explanation of symbols]

 1 atmosphere furnace 2 preheating chamber 1 3 preheating chamber 2 4 heating chamber 5 cooling chamber 6 inlet 1 7 pipe 8 beam 9 door 10 carry-in direction 20 conduit 21 inlet 2 30 low temperature gas inflow 31 heated Gas flow 32 Inflow of gas after heating 41 Panel heater 1 42 Panel heater 2 43 Panel heater 3

Claims (2)

[Claims] 1. In a reflow atmosphere furnace having a preheating chamber and a main heating chamber, a conduit made of a heat-resistant material for flowing an atmospheric gas is provided so as to penetrate the preheating chamber to absorb heat from the preheating chamber. To obtain a high temperature atmosphere gas, thereby supplying a high temperature gas in a reflow atmosphere furnace. 2. A high-temperature gas supply device in a reflow atmosphere furnace according to claim 1, wherein a conduit, such as a hollow box, which is a heat-resistant member for flowing the atmospheric gas is provided outside the preheating chamber and the main heating chamber.