JPS6393473A - Hot wind generator for hot wind type solder melting device - Google Patents

Abstract

PURPOSE:To adjust a feeding quantity of heat with simple operation by dividing plural heaters into two sets and making them controllable independently. CONSTITUTION:A pressure adjusting valve 13 is adjusted so as to attaining to a specific flow amount by opening 1st, 2nd solenoid valves 10, 11. When an electric power is fed to three heaters 3, 3', 3'' in this state, a hot air is blasted from the flowout ports of the heaters 3, 3', 3''. This air blast generates a vortex with its confluence after colliding once with the funnel part 4 of a nozzle 6 after passing through a temp. detector, blasting with stirring each other. A lead piece only is thus heated selectively and the solder on the board opposing thereto is melted. In this process, a control circuit 15 adjusts the hot air temp. so as to attain to the set value by reducing the electric power to the heaters 3, 3', 3'' when the temp. of the hot air exceeds the set value.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a structure of a hot air generator for opening a solder melting bag that uses hot air as a heat source for removing and attaching a flat back IC soldered to a printed circuit board. Regarding.

(Prior Art) In response to recent demands for high-precision packaging, electrical components p, p' such as semiconductor integrated circuits are connected to lead pieces r, r, r, etc. from the side of the package as shown in FIG. ... are flat-packed by extending them approximately parallel to each other. This flat-packed electrical component can be surface-mounted by soldering to the surface of a printed circuit board without using a socket, making it possible to effectively utilize the surface of the printed circuit board and improve mounting efficiency. This has a big effect.

However, when soldering to a printed circuit board, or if it becomes necessary to replace a fully mounted flatback IC due to a failure or a change in specifications, it is necessary to remove the solder from all lead pieces connected to the printed circuit board. There is a problem in that it cannot be removed unless it is melted at the same time.

For this reason, a hot air generator H having a heating wire J housed in a nozzle N formed to match the shapes of various flatback electrical components p and p' as shown in FIG. After fixing the circuit board by suctioning it to a tension pad, the hot air generator H is lowered to the circuit board, and hot air is blown out from the nozzle N to melt the solder on the board.

By the way, semiconductor packages come in various sizes, and it is necessary to adjust the amount of hot air bubbles accordingly, so conventionally, the power supplied to the heating wire J and the flow rate of gas have been adjusted. Another problem is that the two parameters, temperature and flow rate, are interrelated, making control complicated.

(Purpose) The present invention has been made in view of such problems, and its purpose is to supply heat ff1 with a slow operation.
The object of the present invention is to provide a hot air generator that can be adjusted.

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

1.2 each show an embodiment of the present invention, in which reference numeral 1 is a hot air generator, and inside the cylindrical case 2, one end communicates with a pressure source (not shown). Inlet 3
a, and a heat-resistant cylinder 3c with an outlet 3b formed at the other end.
A plurality of (in this embodiment, three) cylindrical heaters 3.3" and 3" each containing a heat generating wire 3d are arranged and housed with the outlet 3b facing the center line. The outlet ports 3b, 3b, and 3b are configured by disposing a load section 4 facing the air and connecting a nozzle 6 having a blowout port 5.5.5.5 at the tip. .

In the figure, reference numeral 7 indicates a suction vibrator whose one end is connected to a negative pressure source, and 8 indicates an elevating mechanism for vertically moving the main body of the hot air generator 1 relative to the circuit board.

FIG. 3 shows an embodiment of the control system for the snow making machine, in which reference numerals 10 and 10 in the figure are first and second solenoid valves, respectively, and on the inflow side there is a pressure sensor. vessel 12, flow meter 13
, and the pressure regulating valve 14 to the air source, and on the outlet side, one or two heaters 3', 3'' inlet ports 3a, 3 are connected.
a, and the other end is connected to the inlet 3a of a single heater 93. 15 is a control circuit which receives the temperature signal from the temperature sensor 6 and the pressure signal from the pressure sensor 17, and adjusts the temperature of the hot air to a set value. In addition to adjusting the power to heaters 3.3' and 3°, the power supply to heaters 3.3' and 3'' is stopped when the signal from pressure detector ]6 falls below the set value. It is configured as follows.In addition, the reference numerals 17 and ]8 in the figure
shows a needle valve that adjusts the ejection flow rate ratio of gas from the first and second gases.

In this embodiment, a large flat package IC is now available.
(Fig. 4 A), the first and second solenoid valves 10 are soldered.
．． 11F8. Pressure regulating valve 1 so that it opens to a predetermined flow rate.
Adjust 3. In this state, the three heaters 3.3', 3
When power is supplied to the heater 3, hot air is ejected from the outlet 3b of the heater 3.3', 3''. This hot air is used as a temperature sensor]6
After passing through, the load section 4 of the nozzle 6 located closest to
After colliding once, they merge to generate a vortex, move toward the outlet 5.5.5.5 while stirring each other, and are ejected from the outlet 5.5.5.5. . As a result, only the lead piece r is selectively heated and the solder on the board facing it is melted. In this process, when the temperature of the hot air exceeds the set value, the control circuit 15 controls the heater 3
．． Reduce the power to 3' and 3" to adjust the hot air temperature to the set value. Also, when the gas supply stops,
Since the signal from the pressure detector 12 falls below the set value, the control circuit 15 urgently stops power supply to the heaters 3.3' and 3'' to prevent the heaters 3.3' and 3'' from overheating. .

When the solder is completely melted, heat/; 13.3', 3
When the power supply to the hot air generator 1 is stopped, the gas is ejected from the air outlet 5.5.5.5 without being heated and the lead pieces are cooled by r%.When the solder solidifies, the hot air generator 1 Raise the nozzle 6 from the IC.

On the other hand, when soldering a flat pack IC with a small number of lead pieces as shown in FIG. 4(b), for example, the second solenoid valve 11 is closed and the heater 3 When the device 3 is operated with the power supply stopped, the two heaters 3', 3 receive the same flow rate and power supply as the large IC described above and generate hot air. Therefore, each of the heaters 3° and 3'' generates hot air without disturbing the air quality and temperature of each heater. After passing through the temperature sensor] 6, this hot air once collides with the load portion 4 of the nozzle 6 that is positioned immediately above H, and then merges to generate a vortex and mutually agitate the air outlet 5. .5.5.5 and ejects from the outlet 5.5.5.5. As a result, the heater 3, which is in a rest state, ejects as much hot air as its heat l, which is proportional to the number of lead pieces r. Heat to a certain temperature.

In this example, C is 15! depending on whether three heaters are used or the capacity of the heaters. It is clear that the number of heaters supported can be increased or decreased.

In addition, in this embodiment, a plurality of heaters 3°, 3°
It goes without saying that the same effect can be obtained even if the ``controllers'' are commonly controlled as a set, or if each unit is controlled independently.

(9jJ result) As explained above, according to the present invention, a plurality of heaters each having a heat generating wire housed in a container body having a gas inlet at one end and an outlet at the other end are connected to each outlet or to a common axis. At the same time, the load section was placed opposite to the outlet near this outlet and communicated with the outlet, so the hot air ejected from the heater collided with the load section, and then merged and created a vortex flow. Since they generate and stir each other, hot air of uniform temperature can be blown out from each outlet. Since the plurality of heaters are divided into at least two sets and can be controlled independently, the temperature and air volume can be easily adjusted, and hot air with a heat amount corresponding to the number of reed pieces can be easily generated.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the device showing an embodiment of the present invention, Fig. 2 is a top view of the same device, Fig. 3 is a configuration diagram showing the control system of the above device, and Fig. 4 (A) ( B) is a perspective view showing an example of a flat back IC, and FIGS. be.

Claims (1)

[Claims] A plurality of heaters containing heating wires are arranged in a container body having a gas inlet at one end and an outlet at the other end so that each outlet faces a common axis, and a load section is placed near the outlet. are arranged facing each other and communicated with the hot air outlet,
A hot air generator for a hot air type solder melting apparatus, wherein the plurality of heaters are divided into at least two sets and can be independently controlled.