JPH0779193B2 - Hot air solder melting device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solder melting apparatus that uses hot air as a heat source for removing and mounting a flat pack IC soldered to a printed circuit board.

(Prior Art) In response to the recent demand for high-density packaging, electrical components P, P ', such as semiconductor integrated circuits, have lead pieces r, r, r ... From the side surface of the package as shown in FIG. Are extended in parallel to form a flat pack. Since this flat-packed electric component can be surface-mounted by soldering on the surface of the printed circuit board without passing through a socket, it is possible to effectively use both sides of the printed circuit board and improve the mounting density. It has a great effect.

However, when it is necessary to replace the mounted flat pack IC due to a failure or change in specifications, it is impossible to remove it unless all the lead pieces connected to the printed circuit board are melted at the same time. There is.

For this reason, a hot air generator H having nozzles N formed in conformity with the shapes of various flat pack electric components P and P'as shown in FIG. 5 is attached to the substrate positioning mechanism S so as to be vertically movable. A state in which the solder melting device is used to fix the printed circuit board to the positioning mechanism S and the electrical component P to be removed is set below the nozzle N, and then the hot air generator H is lowered to cover the outer periphery of the electrical component P with the nozzle N. The hot air is blown out to melt the solder, and the solder is removed from the printed board by the suction device housed in the nozzle N.

However, according to such a device, since the entire outer surface of the electrical component to be removed is covered with the nozzle N, precise alignment of the electrical component P and the nozzle N, which are symmetrical to be removed, is difficult. Not only that, but there is a problem that it becomes impossible to grasp the progress situation of the work and the printed circuit board is destroyed by heating more than necessary.

(Object) The present invention has been made in view of such a problem, and an object of the present invention is to use a hot-air type that allows work to be performed with an electric component to be removed exposed to the outside. It is to provide a solder melting device.

(Structure) Therefore, details of the present invention will be described below based on illustrated embodiments.

1 and 2 each show an embodiment of the present invention. In the drawings, reference numerals 1, 1, 1, 1 denote hot air generators, which are moved up and down by an elevating mechanism 2 such as an air cylinder. Position adjusting mechanisms 5, 5 are provided around the window 4 provided on the base body 3 with a space of about 90 ° so that the discharge port 1b of the window 4 faces each other.
5, 5 and 5 are arranged so as to be movable in the axial direction. Each of the hot air generators 1 has a connection portion 1a communicating with a pressure source (not shown) at one end, and a heater 1d housed in a heat-resistant cylinder 1c having a discharge port 1b formed at the other end. It is attached to the adjusting mechanism 5. Reference numerals 6, 6, 6 and 6 denote nozzles, and as shown in FIG. 3, a long opening 6a corresponding to the side length of the flat pack electric component to be removed is formed at the tip and the other end is the nozzle holder 7 An air guide passage that is connected to the projecting port 1b of the hot air generator 1 via the
6b is formed, and an engaging claw 6c that engages with the nozzle holder is provided on the nozzle holder side, and is detachably fixed to the holder 7 with a screw 7a.

Reference numeral 8 denotes a printed board positioning mechanism provided below the base body, which is provided above the base 8a of the base 9 which is movable in the XY directions.
Gripper 10 according to the width of the target printed circuit board PC
The substrate holder 10 having adjustable a and 10a is mounted. Reference numeral 11 denotes a component suction tool, which is structured such that a suction pad 11a connected to a vacuum source (not shown) by a tube 12 is elastically movable in the vertical direction, and one end is fixed to the other end of an arm 13 detachably attached to the base body 3. The suction pad 11a is arranged so as to be located at the center of the space surrounded by the four nozzles 6, 6, 6, 6.

Reference numeral 14 in the figure denotes a temperature sensor for detecting the temperature of hot air, and 5a denotes a lock bolt for fixing the hot air generator 1 at a predetermined position.

In this embodiment, a nozzle 6 having an outlet 6a corresponding to the length of the side of the flat pack electric component P to be removed is attached to each holder 7, and the lifting mechanism 2 causes the base 3 to move.
Mounted on the printed circuit board PC in the state of pulling up, and operates the positioning mechanism 5 to remove the electric component P.
Are moved to an area surrounded by the four nozzles 6, 6, 6, 6.

By the way, the respective nozzles 6, 6, 6, 6 are arranged so as to extend from the outside of the electric component P, and the peripheral surface of the electric component P,
And the upper space including the upper surface is open, the substrate 3
The electric parts can be seen through the window 4 (see FIG. 4). Therefore, the position adjusting mechanism 5 finely adjusts the position of each nozzle 6 so that the hot air blown out from the outlet 6a of the nozzle 6 hits the lead piece of the flat pack electrical component according to the soldering state or the positional deviation. It becomes possible.

At the stage of completing such preparations, heaters are supplied to all hot air generators 1 while supplying air or an inert gas such as nitrogen.
Energize 1d. When the temperature of the gas ejected from the hot air generator 1 becomes sufficient to melt the solder, the substrate 3 is lowered by the elevating mechanism 2, and the high temperature gas ejected from the hot air generator 1 is introduced into the air guide passage of the nozzle 6. Solder that connects the lead piece and the printed circuit board PC by concentrating on the flat space formed by 6b and rectifying and jetting it obliquely downward from the outlet 6a and hitting the lead piece of the electric component intensively. To heat. The gas provided for heating is guided along the surface of the printed circuit board PC and the outer surface of the electric component P, and subsequently into a cylindrical space surrounded by the wall surface forming the airflow passages 6b of the four nozzles 6. While rising, it rises by natural convection and diffuses into the atmosphere.

In this way, when the solder 3 is melted and the gas 3 is raised by the elevating mechanism 2 while applying a suction pressure to the suction pad, the electric component P is adsorbed by the suction device 11 and detached from the printed circuit board PC.

When soldering a new part to the part where the part has been removed, apply cream solder to the surface of the mounting part according to the pattern, position the lead piece of the electrical part to be mounted on this, and then remove it as described above. All you have to do is go through the same steps as when.

In addition, as shown in FIG. 6 (b), when detaching an electric component in which lead pieces are provided only on two opposing sides,
It is possible to remove the hot air generators by operating the two opposed hot air generators and following the above process. in this case,
Nozzle replacement is not required in most cases because the package sizes are standardized.

Although the hot air generator is moved in the vertical direction in this embodiment, the positioning mechanism of the printed circuit board may be moved in the vertical direction, and further, the base body 3 to which the hot air generator is attached is attached to the X-axis. Even if it is moved in the -Y direction, the same effect is obtained.

In addition, not only can the heat loss be reduced by forming the nozzle from ceramics, but also the hot air generator and the printed circuit board can be electrically insulated and electrical components on the printed circuit board can leak. It can be protected from destruction by the like.

(Effect) As described above, according to the present invention, a plurality of hot air generating means are arranged substantially horizontally so that the discharge ports are located on the four sides,
Since hot air is blown out through the nozzle, the upper surface of the device is flattened to improve workability and make the device compact, and the upper part of the electrical component to be removed can be always opened. In addition, the high temperature gas used for heating the solder can be quickly discharged from above to prevent overheating of the printed circuit board. Furthermore, by independently operating the hot air generating means, only the two opposite sides can be operated. With the electric component provided with the lead piece, the work can be performed without replacing the nozzle. Further, since the heating base is jetted downward and forward by the nozzle, the distance between the two nozzles facing each other can be made large, and the lead piece may come into contact with the nozzle and drop off from the suction means when the electrical component is removed. Not only can it be prevented in advance, but the distance between the nozzle and the printed circuit board can be increased,
The amount of radiant heat from the nozzle that reaches the printed circuit board can be reduced to prevent unnecessary heating of the printed circuit board and surrounding components. Furthermore, it is sufficient for the nozzle to simply have the function of adjusting the hot air blowing pattern.
It is possible to reduce the weight, and it can be expected that the rate of temperature rise will be improved by reducing the thermal inertia.

[Brief description of drawings]

1 and 2 are a cross-sectional view and a top view of an apparatus showing an embodiment of the present invention during solder melting work, and FIGS. 3 (a) and 3 (b) are nozzles used in the same apparatus, respectively. FIG. 4 is a perspective view showing an embodiment, FIG. 4 is a perspective view showing a work area in the same apparatus, and FIGS. 5 (a) and 5 (b) are perspective views showing an example of a conventional hot-air solder melting apparatus and their operation. FIG. 6 is an explanatory view showing a state, and FIGS. 6 (a) and 6 (b) are perspective views showing examples of flat-packed electric parts. 1 ... Hot air generator, 1b ... Discharge port 3 ... Substrate, 6 ... Nozzle 6a ... Blowout port, 6b ... Bladder part

Claims (1)

[Claims] 1. A plurality of hot air generating means are arranged in a substantially horizontal direction on a base body which can move up and down relatively above a mechanism for positioning a printed wiring board so that each discharge port is located on four sides, and a gas is provided. A hot-air solder melting apparatus in which a nozzle having an outlet corresponding to the side length of an electric component is detachably provided at the tip of a wind guide portion for ejecting the air obliquely forward to the discharge port of the hot-air generating means.