JPH0755375B2 - Hot air solder melting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hot-air solder melting apparatus used for mounting a flat-pack type IC on a printed circuit board and for removing an IC mounted on the board. .

(Prior Art) In response to the recent demand for high-density mounting, electrical components such as semiconductor circuits are flattened by extending lead pieces from the sides of the package substantially in parallel as shown in FIG. , Configured as a so-called flat package. Since such a flat packaged electric component can be surface-mounted by soldering on the surface of the printed circuit board without passing through the socket, it is possible to effectively use the surface of the printed circuit board and improve the mounting density. There are great advantages.

However, when soldering to the board, or when replacing a flat pack IC that has been mounted due to a failure or specification change, it is necessary to melt all the lead pieces welded to the printed board at the same time, which is a problem that cannot be removed. There is.

Therefore, after the flat pack IC is sucked and fixed to the suction pad using a hot air generator containing a suction pad communicating with the negative pressure source in the nozzle formed according to the shape of the flat pack IC, Is lowered to the circuit board, and hot air is blown from the nozzle to melt the solder on the board.

However, since the suction pad is usually made of an elastic material such as silicon rubber, when the electric component is pressed against the circuit board, the suction pad is elastically deformed to cause a positional shift, which may cause a connection error. Not only is there
There is a problem that the suction pad is easily deteriorated because it is exposed to hot air.

In order to solve such a problem, the applicant of the present invention, as shown in FIG. 6, has a step in which the inner wall is in contact with the peripheral surface of the package of the electric component and is in contact with the surface of the package at the position where the lead portion of the package is exposed. A member b having a portion a,
The outer cylinder c regulates the outlet e of the nozzle tip d, and the space f formed by the step a and the package surface.
We proposed a hot-air type soldering device, which is connected to a negative pressure source.

According to this device, it is not only possible to improve the positioning accuracy and reliability of the flat pack IC by eliminating the need for accommodating the suction pad inside the nozzle, but also it is possible to reduce the size of the nozzle, and it is possible to achieve a very small IC. Also, there is an effect that soldering by hot air is possible, and further, the space forming the suction portion acts as a heat insulating layer to prevent the temperature rise of the IC.

In this way, the size can be reduced, but on the other hand, there is a disadvantage that the air mixing in the hot air generator is not uniformly agitated and the hot air tends to have temperature unevenness.

(Problems to be Solved) The present invention has been made in view of such circumstances, and an object of the present invention is to provide a novel solder having a uniform temperature distribution regardless of downsizing of a hot air generator. It is to provide a hot air generator for melting.

(Means for Solving the Problem) In order to solve such a problem, in the present invention, the hot air is supplied from the hot air generator via a cylindrical hot air derivative, and an electric component adsorption tool is provided at the lower end. In a hot-air solder melting apparatus including a nozzle having the hot-air generator, the hot-air generator has a cylindrical body having a circular cross section for accommodating a heater arranged in an axial direction, a plug for supporting the heater, and An air inlet for generating an air flow is bored in the tangential direction of the tubular body, and the plug is constituted by a base body that fixes the plug to the rear end of the tubular body.

(Operation) Compressed air is blown from the tangential direction of the inner peripheral surface of the cylindrical body having a circular cross section containing the heater, and the compressed air is spirally swirled in the cylindrical body to be sufficiently agitated, and then ejected from the nozzle, Therefore, hot air having a uniform temperature is obtained.

(Example) Therefore, the details of the present invention will be described below based on an illustrated example.

FIG. 1 is a sectional view of an apparatus showing an embodiment of the present invention, in which reference numeral 1 is a base made of a refractory material such as metal having a through hole 2 formed in the axial direction, A cylindrical body 3 having a circular cross-section for accommodating a heater 6 to be described later and ejecting hot air from the tip is fixed to one end of 2, and a plug 4 is detachably attached to the other end of the through hole 3 with a screw or the like. Further, an air injection hole 5 is formed on the side surface of the substrate 1 so as to be in communication with the outside in alignment with the tangential direction of the through hole 2.

On the other hand, the tip end surface of the plug 4, that is, the insertion surface into the through hole 2, has a length that can be accommodated in the tubular body 3, and enables movement of the airflow between the tubular body 3 and the plug. The heater 6 formed by winding a heating wire such as a nichrome wire so as to have an outer diameter is self-sustaining, that is, it is planted so as to maintain a linearly extending posture without requiring support from the surroundings. Note that reference numerals 7 and 7 in the figure denote lead wires for supplying power to the heater 6.

According to this embodiment, when the air injection hole 5 is connected to the compressed air source and the heater 6 is energized, the air flowing in from the air injection hole 5 flows in from the tangential direction of the inner peripheral surface of the through hole of the base 1. The heater 6 is rotated while turning around the center line of the tubular body 3.
Pass through. In the process of this passage, the air is heated by the heater 6
It flows into every corner of the cylinder and receives heat to be heated, and at the same time, the surrounding air is agitated by its own swirling motion to become a uniform temperature and is jetted from the tip of the cylindrical body 3.

On the other hand, when the heater 6 is broken due to long-term use, the plug 4 is removed from the base body 1, the heater 6 is pulled out from the tubular body 3, and a new heater is installed to set the plug. Can be exchanged.

FIG. 2 shows an embodiment of a hot air type solder melting apparatus using the hot air generator described above, in which reference numeral 10 is a base 11
In the main body of the hot air generator installed to be movable up and down, a nozzle member 13 having a blowout port 15 for adsorbing the flat packed IC and ejecting hot air to the lead portion of the flat packed IC is attached to and detached from the lower end of the housing body 12. It is provided freely.

The nozzle member 13 has an inner surface that conforms to the shape of the peripheral surface of the flat packed IC and an outer surface that forms a blowout port 15 having a constant gap with the outer cylinder 14 and a wall portion 16a that is in contact with the surface of the flat packed IC and leads. A partition member 16 is formed at the tip corner of the outer cylinder 14 and is joined to the surface of the wall portion while restricting the height at which the piece is exposed and having a stepped portion 16b forming a suction chamber 17 whose central portion is connected to the suction tube 20. It is configured to form an outlet 15 with the outer cylinder 13.

A plurality of through holes 3 are provided in the upper part of the housing cylinder 12, and three through holes 3 in this embodiment.
A mounting frame 30 in which 1, 31, 31 are drilled at equal intervals is fixed (Fig. 3), and the hot air generator described above is inserted and fixed in each through hole 31 with its tubular body facing downward, and each compression hole is compressed. A compressed air source is connected to the air injection hole 5.

In this embodiment, when the flat packed IC to be soldered by connecting the suction tube 20 to the negative pressure source is inserted into the suction chamber 17, the flat packed IC has its peripheral surface on the wall portion of the partition member 16 and also on the surface. Is regulated by the step portion 16b and is held in the suction chamber 17 located above with negative pressure.

In this state, when the heater 6 of each hot air generator is energized and compressed air is supplied to the air injection hole 5, the air flowing in from the injection hole 5 flows in from the tangential direction of the inner peripheral surface of the through hole 2 of the base 1. And passes through the heater 6 while turning around the center line of the tubular body 3. In the course of this passage, air flows into every corner of the heater 6 and receives heat to be heated,
At the same time, the surrounding air is agitated by its own swirling motion to obtain a uniform temperature, which flows into the nozzle member 13 from the tip of the cylindrical body 3 and jets from the outlet 15 to apply the cream solder previously applied to the circuit board. It is melted and soldered.

FIG. 4 shows an embodiment of the above-mentioned mounting frame, and reference numeral 40 in the drawing denotes a housing barrel 12 (FIG. 2) of the hot air generator.
A plurality of through holes 42, 42, 42 having a circular cross section are formed at equal intervals around the lead-out hole 41 of the negative pressure supply pipe 20, and in this embodiment, as a base body which also serves as a mounting frame. The compressed air injection ports 43, 43, 43 are formed so as to communicate with each other in the tangential direction of each through hole 42.

In this embodiment, the tubular bodies 44, 44, 44 are fixed to the tip of the through hole, that is, the nozzle side, and the above-mentioned plug 4 (FIG. 1) is attached to the other end side of the through hole, thereby providing a hot air generator. The heater assembly is suitable.

FIG. 5 shows a second embodiment of the present invention, in which reference numeral 50 designates a hot air guide having a circular cross section in which a nozzle 51 having a suction chamber of a flat packed IC is detachably provided at the tip. An inner cylinder 52 is coaxially arranged inside, and a gap is provided so as to form outlets 53, 53 at the tip end portion. One end of a plurality of cylindrical bodies 55, 55, 55 is fixed to the upper part of the hot air guide 50 so as to match the tangential direction of the inner peripheral surface of the guide, and the heaters 56, 56, 56 are housed therein, and A compressed air source is connected to the other end, and a compressed air inlet 57 is provided separately from these sources. Reference numeral 58 in the figure indicates a suction tube.

In this embodiment, when compressed air is supplied while the heaters 56, 56, 56 are energized, the hot air blown out from the tubular members 55, 55, 55 flows in from the tangential direction of the inductor 50 and the space between it and the inner cylinder 52. It reaches the nozzle 51 while making a swirling motion and is ejected from the outlet 53.

In this process, the hot air that has flowed in from each tubular body 55 is agitated with each other in the space formed by the inductor 50 and the inner tube 52 to have a uniform temperature. Also, when soldering is completed,
When the heater is de-energized and the compressed air is injected from the compressed air inlet 57, the cool air is blown out from the outlet 53 within an extremely short time to quickly cool the lead piece after soldering.

According to this embodiment, since the body for fixing the nozzle 51, that is, the hot air guide 50 can be formed as thin as possible, the blind spot is reduced, and the positioning accuracy and workability can be improved. .

In this embodiment, compressed air is injected from the end of the tubular body 55, but the hot air generator shown in FIG. 1 can be used to double stir the air. As a result, hot air with a more uniform temperature distribution can be obtained.

(Effects of the Invention) As described above, in the present invention, hot air is supplied from the hot air generator via the cylindrical hot air derivative, and the hot air is provided with the nozzle having the electric component adsorption tool at the lower end. In the solder-melting device, the hot air generator has a cylindrical body having a circular cross section for accommodating the heater arranged in the axial direction, a plug for supporting the heater, and an air flow in the tangential direction of the cylindrical body. Since the air inlet to be generated is formed and the plug is constituted by the base body fixing to the rear end of the cylindrical body, the air heated by the heater can be sufficiently agitated and then ejected. Not only will reliable soldering be possible with even hot air,
The abnormal heat generation of the heater can be prevented to extend the life of the heater, and the heater can be replaced by replacing the plug.

[Brief description of drawings]

1 (a) and 1 (b) are sectional views of an apparatus showing an embodiment of the present invention, and FIG. 2 is a sectional view showing an embodiment of a solder melting apparatus using the same hot air generator, and FIG. FIG. 4 is a top view showing an embodiment of a mounting frame body in the apparatus shown in FIG.
FIGS. 5 (a) and 5 (b) are sectional views showing other embodiments of the frame body, FIG. 5 (a) (b) are sectional views showing other embodiments of the present invention, and FIG. FIG. 7 is a diagram showing an example of a conventional hot air type solder melting device, and FIG. 7 is a diagram showing an example of a flat packed IC. 1 ... Substrate, 2 ... Through hole 3 ... Cylindrical body, 4 ... Plug 5 ... Air injection hole, 6 ... Heater 13 ... Nozzle member

Claims (2)

[Claims] 1. A hot-air solder melting apparatus which receives hot air from a hot-air generator via a cylindrical hot-air derivative and which is provided with a nozzle having an electric component adsorption tool at a lower end, wherein the hot-air generator is A cylindrical body having a circular cross section for accommodating the heater arranged in the axial direction, a plug for supporting the heater, and an air inlet for generating an air flow in the tangential direction of the cylindrical body. And a base for fixing the plug to the rear end of the tubular body, the hot-air solder melting apparatus. 2. The hot air solder melting apparatus according to claim 1, wherein the hot air generator is attached so that the hot air from the hot air generator swirls inside the cylindrical hot air derivative.