JPS6354798A - Method of soldering flat pack ic on printed board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for mounting a flat pack IC on a printed circuit board and soldering the pads of the printed circuit board and the leads of the flat pack IC to be connected to each other. This invention relates to a novel method for soldering a flat pack IC to a printed circuit board, in which soldering is performed while applying an external force from the outside of the flat pack IC.

[Conventional technology]

Conventional equipment combines a laser with a flexible optical fiber processing system, irradiates the beam onto the area to be processed and solders it, or connects the area by blowing hot air onto the area to be processed. A known method is to press an electric iron directly onto the part to be soldered.

[Problem that the invention seeks to solve]

However, when optical equipment is used, it is expensive because it requires a complicated optical system. In addition, when connecting using an optical system or hot air, if the leads on the flatback IC side (sometimes referred to as terminals) are not on the same plane and are uneven, supply solder to the pads and pads of the printed circuit board.
When a flat punk IC lead is installed on this, 3
Some of the leads of the flat pack IC are separated from the pads of the printed circuit board, creating gaps between them and the pads of the printed circuit board. Therefore, even if a beam is irradiated or hot air is supplied to the part to be connected in this state, connection will not be possible in the part where the above-mentioned gap is formed.

In addition, in the case of the contact type using an electric iron, impurities attached to the flux, iron tip, etc. are interposed in the soldering area, which often causes connection failures and makes it difficult to achieve uniform soldering. be. moreover,
The work efficiency is extremely low because the electric iron is pressed against each part to be connected and soldered.

In the present invention, the leads of a flat pack IC are uneven,
Even if everything is not on the same plane, there is a flat surface on the printed circuit board.
When mounting a flat pack IC and performing connection work, pressure is applied from the outside of the flat pack IC to forcibly press the leads of the flat pack IC to the pads of the printed circuit board to connect the printed circuit boards ( The contact surface between the opposite lead and the pad of the flat panel IC is brought into close contact.

It is an object of the present invention to provide a method for soldering a flatback IC to a printed circuit board, which allows soldering to be performed extremely efficiently without connection failure while maintaining this close contact state.

[Means for solving problems]

In order to solve the above-mentioned problems, the method of the present invention mounts a flat punk IC on a printed circuit board, and connects pads of the printed circuit board and flat punk IC to each other.
Align with the lead of C, then flat punk I
This printed circuit board is characterized in that pressure is applied from the outer surface of the IC toward the printed circuit board to bring all the leads of the flat pack IC into close contact with the pads of the printed circuit board, and soldering is performed while maintaining this close state. The present invention provides a flat pack IC soldering method.

[Effect]

Place the printed circuit board in a predetermined position on the work table using an appropriate method. Then, the flat pack IC is mounted on the mounting position on this printed circuit board, and the pads of the printed circuit board to be connected to each other and the leads of the flat pack IC are aligned. Next, pressure is applied from the outer surface of the flat pack IC toward the printed circuit board. This pressurization forces all the leads of the flat pack rC into close contact with the pads of the printed circuit board. Soldering can be carried out by irradiating the heat rays from the heat source unit onto the part to be soldered while maintaining this close contact state. in this way,
At the time of connection, pressure is forcibly applied from the outside of the flat puncture IC to bring all the leads of the flat puncture IC into close contact with the pads of the printed circuit board. Since the connection work is carried out while maintaining this close state, the contact surfaces of the leads and the blades to be connected to each other come into full contact, thus reliably avoiding the problem of poor connection.

〔Example〕

Examples will now be described with reference to preferred apparatus for carrying out the method of the invention.

The base plate 1 is fixed to a suitable fixing member not shown in the drawings, such as a work table. A fixed cylinder 2 is provided on the base plate l. The lower end of the stand 3 is inserted into the fixed tube 2 and fixed with a fixing screw 4. A stopper 5 is fitted into the stand 3 and fixed to an arbitrary position in the axial direction of the stand 3 by a stopper screw 6. A sleeve 7 is fitted into the stand 3, and a spring 8 is interposed between the sleeve 7 and the stopper 3. Sleeve 7 has fixing screw 9
Fix it to stand 3 with. 10 is a key, the tip of which is the key formed on the above stand 3? gll to prevent rotation of the sleeve 7.

The sleeve 7 is provided with a bracket 12.

One end of the spacer shaft I3 is inserted into the bracket 12, and the other end is inserted into the bracket 14.

The spacer shaft 13 is attached to the bracket 12.14 with an adjusting screw 1.
5.16 respectively adjustable and fixed. With such an adjustment mechanism, the stand 3 and the main shaft 19, which will be described later,
The distance between the two is adjusted. The bracket 14 is connected to the support tube 17
and is fixed with the fixing screw 18.

A main shaft 19 passes through the support cylinder 17 and projects its upper end outside the cap 20. This cap 20 is attached to the support tube 17
It is screwed into the top opening of the.

A double nut 21 is threadedly coupled to the protruding end of the main shaft 19, and by adjusting the nut 21, the m2F8 adjustment in the axial direction of the main shaft 19 can be performed. In FIG. 1, the support tube 17 has play holes 22, 22 formed at the lower end thereof at positions that match each other. These play holes 22.22 are provided with guide pins 2
3 so that it can move freely. The guide pin 23 is connected to the main shaft 19
It penetrates through the hole 22, and both ends thereof are inserted into the play hole 22 so as to be freely movable. A spring 29 is interposed between the main shaft 19 and the cap 20. The above guidance adjustment is finely adjusted within the range of the play hole 21 by adjusting the screwing amount of the double nut 21. Main shaft 19
The lower end passes through the base 24 and projects further downward in FIG. The lower end of the rod 25 is screw-coupled to this protruding end. A pressing plate 26 is fixed to the lower end of the rod 25. This pressing plate 26 is used to hold the flat punk IC 28 during soldering (mounting) work.
Press down on the top. That is, cream solder, for example, is applied to the pads of the printed circuit board 27, and the leads 27a of the flat pack IC 28 are matched with this. By applying the above pressure, all the adhesive of flat punk TC2B -
The pad 28a is forcibly brought into close contact with the pad 27a of the printed circuit board 27. This close state is maintained as long as the pressing plate 26 presses the flat pack IC.

Further, a spring 29 exerts an acting force on the main shaft 19 in order to buffer the impact when the pressing plate 26 comes into contact with the flat pack IC 28.

The spring 29 has a guide pin 23 passing through the main shaft 19.
and the cap 20. As a modification of the above-described pressing plate 26, the pressing plate 26 may be formed with a heat ray passing portion such as a slit so that the heat ray is irradiated only to the area to be soldered through the heat ray passing portion.

The mounting base 24 is formed in the shape of a truncated pyramid, and has a concave fitting portion 30 on its upper surface side. The lower end of the support cylinder 17 is fitted into the fitting part 30, and the mounting screw 3
1.31, the lower end of the support tube 17 is removably attached. The mounting base 24 has a retaining arm 32.3.
3 is attached in a symmetrical position with bolts 34 and 34. The holding arms 32.33 are mounted at an angle, and the free ends of the holding arms 32.33 are bifurcated. A heat source unit 35 is placed between these two forked pieces.
．． A mounting piece 36, 36 provided at the center of the upper surface of 35 is inserted and fixed by tightening with an angle adjusting shaft 37, 37 such as a screw. The heat source unit 35.35 has the angle adjustment shaft 3
It moves on a trajectory of radius R centered at 7.37 and is fixed at any position. Therefore, when soldering the flat pack IC 28 to the print 27,
Dimension l between flat pack ICs 28, i.e. flat 7
A heat source unit 35 is attached to the pad 28a of the Tobasoku IC 28.
Match the hot wire from 35. This focusing causes the heat source unit 35.35 to pivot about the axis 37.37,
Just fix it and set it.

Therefore, even if the dimension l of the flat pack IC to be processed changes, the focus of the heat source unit 35, 35 can be freely changed to perform soldering.

The thermal unit 35 will be explained with reference to FIGS. 3 to 6. The heat source unit 35 includes a reflecting mirror body 38. The reflecting mirror main body 38 has an inner surface formed as a reflecting surface 38a. The entire surface of the reflective surface 38a is plated with gold to further enhance reflection efficiency. Reflector body 38
Both side surfaces of 39. are open, and reflective side plates 39.
39 is the installation. The inner surfaces of the reflective side panels 39 and 39 are also plated with gold.

40 is a ceramic base formed into an L-shape in cross section. Ceramic base 40, 1 heat source socket 4
1 is attached with screw 42. This screw 42 is also screwed to a lamp terminal 43. The lamp terminal 43 is attached to the reflector body 38 with screws 44, and the lamp terminal 43 is connected to a power source. The reflective side plates 39.39 are provided with through holes 45.45. These through holes 45.
A heat source lamp 46 is fitted into the lamp 45 , and its base is supported by the socket 41 . The reflecting mirror body 38 is provided with water cooling passages 47a and 47b (see FIG. 5). aisle 47
An inflow pipe 48a is provided on one end side of a (sixth
(See Figures A and B). The cooling water injected from the inflow pipe 48a passes through the passage 47a and connects to the communication pipe 4 to the passage 47b.
9 and enters the passage 47b. The cooling water that has entered the passage 47b is discharged from the outflow pipe 48b. In this way, cooling water is circulated within the reflector body 38. 50 is
It is a housing, and 51 is a cover plate. Reference numeral 52 denotes a hole for introducing a power cord, and each side of the housing 50 is provided with a slit 53 for ventilation.

For example, a flat pack IC28 formed in a square shape
A case will be described in which the circuit board 27 is mounted on the printed circuit board 27.

As shown in FIG. 7, the flat pack TC 28 has leads 28a on each surface thereof, and pads 27a corresponding to these leads 28a are also provided on the printed circuit board 27. A printed circuit board (27) is set directly below the main shaft 17, and cream solder, for example, is applied to the pad 27a.Then, the flat pack IC 28 is mounted on the printed circuit board 27, and positioned and set at the mounting position.Next, the main shaft 19 flat punctures the pressing plate 26 by lowering the
It comes into contact with the top surface of C. At this time of contact, the spring 29
The impact force is absorbed by the acting force.

Therefore, there is no fear that the flat punk IC will be excessively pressurized and one member will be destroyed. By pressurizing the plate 26,
All of the adhesives 28a of the flat punk IC 28 are forcibly brought into close contact with the pads 27a of the printed circuit board 27. Due to this close contact, the pads 27a of the printed circuit board 27 and the leads 28a of the flat punk IC 28 are brought into contact with each other through surface contact and a large contact area.
The connection can be made more reliably. While maintaining this close state, a heat wire of, for example, 200 to 900° C. is irradiated from the heat source unit 35, 35 to the region 280 to be connected (see FIG. 1). These hot wires 35a, 3
5a, the connection parts are instantly soldered.

In this way, when the parts to be connected in two directions facing each other are connected, the main shaft 19 is moved upward, the printed circuit board 27 is rotated 90 degrees, and the same operation as above is repeated again to complete the remaining processing. All you have to do is connect the parts that need to be connected.

In the above case, since the heating wires 35a, 35a have a very high temperature, the reflecting mirror body 38 is also heated to a high temperature.

Therefore, in order to prevent adverse thermal effects, an inflow pipe 48 is installed in the water cooling passages 47a, 47b of the reflector body
Cooling water is made to flow in from a and drained from an outflow pipe 48b, thereby cooling the entire reflecting mirror body 38 from inside. Further, the surface of the reflecting mirror main body 38 is cooled by the outside air entering through the ventilation hole 53. Therefore, the unit is not exposed to high heat and suffers no adverse thermal effects.

FIGS. 8 and 9 show other embodiments of the arrangement structure of the heat source unit. In the above embodiment, two heat source units 35, 35 are used, and a flat punk I
Although we have described the case where parts to be connected in two directions of C are simultaneously soldered, the apparatus shown in FIGS. 8 and 9 uses four heat source units 35, 35, and flat pack I
The four directions of C can be connected simultaneously.

In this example, four heat source units 35.35
and 35.35 are mounted on the mounting base 2 with a 90° interval.
This is attached to 4. These heat source units 35 are each attached to the holding arm 33 via an angle adjustment shaft 37 so that the irradiation angle of the heat ray 35a can be adjusted in the same manner as in the first embodiment. The mounting positions of the respective holding arms 33 with respect to the mounting base 24 are not all mounted at the same height position, but the holding arms 33 arranged opposite to each other are set at the same height position, and the holding arms 33 arranged opposite to each other are mounted at the same height position. Install it at a position different from the height of the Then, a pair of IMI heat source units 35.
When adjusting the angles of the heat source units 35 and 35.35, there is no possibility that the heat source units 35 will collide with each other. In addition,
The structure other than the arrangement of the heat source units is exactly the same as that of the embodiment described in the case of the two heat source units, so illustration is omitted.

[Effect]

A flat punk IC is mounted on a printed circuit board, and the printed circuit board's pad and flat punk IC are connected to each other.
Then, pressure is applied from the outer surface of the flat pack IC toward the printed circuit board to bring all the leads of the flat pack IC into close contact with the pads of the printed circuit board, and soldering is performed while maintaining this close state. Therefore, even if the leads of the flat pack IC are uneven and not all on the same plane, the contact surfaces of the leads of the printed circuit board to be connected to each other and the band of the flat pack IC are brought into close contact when mounting work is performed. Since the connection process is performed while maintaining this close state, soldering can be performed extremely efficiently without connection failures.

[Brief explanation of the drawing]

The drawings show a preferred apparatus for carrying out the method of the invention, and FIG. 1 is a front view of the entire apparatus according to the first embodiment;
Figure 2 is an explanatory diagram of the heat source unit mounting part, Figure 3 is a joint cross-sectional view of the heat source unit, Figure 4 is its plan view, Figure 5 is a side view of the reflector body, and Figure 6 (A) is the water supply. Partial plan view of the system,
(B) is a sectional view taken along line A-A in Figure 4, Figure 7 (A> is a plan view of the part to be soldered), (B)
8 is a plan view of the main part of the second embodiment of the device, and FIG. 9 is a side view thereof. Explanation of symbols 25... Pressure means 27... Pudding FW plate 27a
...Bad 28...Printed circuit board 28.3...
Lead Figure 4 (A) Figure 7 (A) (B) Figure 9

Claims (1)

[Claims] A flat pack IC is mounted on a printed circuit board, and the pads of the printed circuit board and flat pack I that are to be connected to each other
Align with the leads of C, then apply pressure from the outside of the flat pack IC toward the printed circuit board to bring all the leads of the flat pack IC into close contact with the pads of the printed circuit board, and solder while maintaining this close state. A method for soldering flat pack ICs to a printed circuit board, characterized in that: