JP2717789B2 - Electronic component mounting method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for mounting an electronic component on a circuit board. 2. Description of the Related Art For example, a hybrid integrated circuit is configured by mounting electronic components having various functions and shapes on its circuit board. In other words, in addition to electronic components formed to be short and easy to surface mount, such as monolithic ICs, chip resistors, chip capacitors, etc., radial lead type electronic components that are difficult to mount are mounted. Often. Conventionally, as shown in FIG. 4, when a radial lead type electronic component a is inserted into a circuit board b, the terminal lead d is sandwiched by a loading chuck c and the terminal lead d is fixed on the circuit board b. Into the set position and insert head e
The terminal lead d to the circuit board b.
This is performed by inserting into the lead hole f. that time,
The tip of the terminal lead d protruding from the lower surface of the circuit board b is bent by the clincher claw h of the anvil g which moves in the plane direction below the circuit board b in conjunction with the insertion chuck to prevent the electronic component a from falling down. . This is because if the electronic component a falls down after the terminal lead d is inserted, the insertion of an adjacent electronic component to be inserted next will be hindered. When all the electronic components are inserted, the terminal leads d are fixed to the circuit board b by solder. In the above-described hybrid integrated circuit, a chip-type electronic component may be mounted on the back surface of the circuit board in order to increase the mounting density. However,
Conventionally, in the step of inserting the radial lead type electronic component into the surface of the circuit board, since the lead clinch by the anvil is required as described above, there have been the following problems to be solved. First, since the anvil occupies a certain amount of plane space on the back surface of the circuit board, an area equivalent to this becomes a dead space, which is a factor that hinders an improvement in the mounting density of the radial lead type electronic component. Becomes Second, when the radial lead type electronic component is inserted into the front surface of the circuit board, the anvil g moves on the back side of the circuit board. Parts cannot be installed. Thirdly, in connection with the second problem, when electronic components are also mounted on the back surface of the circuit board, the following complicated procedures have to be taken. That is, FIG. 5 (a), (b) as shown in, after producing the circuit board b completing the soldering on the surface while wearing the chip-type electronic component j ₁ to the surface, FIG. (C)
As shown in (1), a radial lead type electronic component a is inserted into the surface of the circuit board b. Then, as shown in FIG. 2 (d), the circuit board b by reversing the chip-type electronic component j ₂ is mounted on the back surface, as shown in the last drawing (e), the circuit board b Is inverted again, and then the back surface is soldered. As described above, in the related art, the above-described series of five steps is performed. This is because the chip-type electronic component cannot be mounted on the circuit board b prior to the mounting of the radial lead-type electronic component a. . After all, conventionally, in a series of work steps, since the front and back of the circuit board b are inverted twice, not only the production line becomes complicated, but also the number of the manufacturing steps is large, and the work efficiency is poor. Had become. The present invention solves the conventional problem described above, and includes a process of manufacturing a hybrid integrated circuit in which a radial lead type electronic component is mounted on the front surface of a circuit board and a chip type electronic component is mounted on the back surface. It is an object of the present invention to provide a simple structure that does not include reversal and to further increase the mounting density of radial lead type electronic components. Means for Solving the Problems To solve the above problems, the present invention employs the following technical means. That is, the present invention provides a process for fixing an electronic component on at least the back surface of a circuit board, and a holding member provided with a sponge-like portion which is elastically deformable and has a certain shape-retaining force. Abutting the sponge-shaped part on the circuit board to back up the circuit board, and an electronic component having a terminal lead inserts the terminal lead into the lead hole of the circuit board from the front side of the circuit board; And a step of piercing the sponge-like portion to be held, and a step of fixing the terminal lead to the circuit board after separating the holding member from the circuit board. According to the present invention, when a so-called radial lead type electronic component having a terminal lead is mounted on a circuit board, the terminal lead of the electronic component inserted into the lead hole of the circuit board is placed below the back surface of the circuit board. The radial lead-type electronic component is temporarily fixed by piercing the sponge-like portion of the holding member disposed in the above, thereby preventing the electronic component from falling down. For this reason, when assembling a plurality of radial lead type electronic components on the surface of the circuit board, it is possible to bring the plurality of radial lead type electronic components close to each other in an upright manner. In the present invention, although a holding member having a sponge-shaped portion is arranged on the back surface of the circuit board, this holding member is
Unlike the anvil conventionally used, no dead space is generated when the radial lead type electronic component is mounted on the front side of the circuit board. Therefore, the mounting density of the radial lead type electronic component can be further increased. Further, in the present invention, unlike the related art, there is no need to provide a space for moving the anvil below the back surface of the circuit board, and at the stage of mounting the radial lead type electronic component on the front surface of the circuit board, Even if a chip-type electronic component or the like is already mounted in advance, this does not cause any problem. Since the sponge-like portion of the holding member is elastically deformable, when the back surface side of the circuit board is backed up by the holding member,
A portion of the sponge-shaped portion that comes into contact with the chip-type electronic component fixed to the back surface of the circuit board is appropriately elastically deformed, and does not damage the chip-type electronic component. Further, in the present invention, after the chip-type electronic component is fixed to the back surface of the circuit board, the holding member is arranged below the back surface of the circuit board, and then the radial lead type electronic component is assembled from the front side of the circuit board. Then, in order to fix the terminal leads to the circuit board after separating the holding member from the circuit board, it is not necessary to invert the front and back surfaces of the circuit board in these series of working steps. For chip-type electronic components to be fixed in advance on the back surface of the circuit board, for example, when fixing the terminal leads of the radial lead-type electronic component to the circuit board, they may be soldered to the circuit board at the same time, or from the beginning. It may be soldered to the back surface of the circuit board. Therefore, in the present invention, it is not necessary to provide a reversing device for reversing the front and back of the circuit board in the production line, so that the configuration of the production line can be simplified, and the number of work steps can be reduced. Efficiency can be improved. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the working process of the electronic component mounting method according to the present invention. The circuit board 1 is sequentially transported to a radial lead type electronic component mounting position by a transport mechanism (not shown), and after the radial lead type electronic component is mounted, is transferred to the next step. A circuit pattern is formed on the front and back surfaces of the circuit board 1, and chip-type electronic components 2 such as a chip-type resistor or a chip-type capacitor are previously placed at predetermined positions on the front and back surfaces in the previous step. … Is attached. A lead hole 5 having a diameter slightly larger than the outer diameter of the terminal lead 4 is formed at a position where the radial lead type electronic component 3 is to be inserted. When the circuit board 1 is conveyed to the electronic component mounting position shown in the figure, the upper surface thereof has a sponge-like portion 6 which can be elastically deformed and can pierce the terminal leads 4... The holding member 7 moves upward, and the upper surface of the sponge-shaped portion 6 backs up the back surface of the circuit board 1. The sponge-like portion 6 is provided on the upper surface of the support plate 8 having the same area and shape as the planar area of the circuit board 1.
By sticking a sponge-like portion 9 having a constant thickness larger than the length of the sponge-shaped portion, the structure can be simplified. It is preferable that the sponge member 9 is somewhat rigid, for example, a so-called IC mat used for temporarily holding an IC by piercing its terminal pin. That is, such a sponge-like IC mat has conductivity and prevents the electronic components from being electrostatically damaged when the terminal lead 4 is pierced into the sponge-like portion 6 as described later. As is clear from FIG. 1, the sponge-like portion 6
Since it is elastically deformable, even if the electronic components 2 are already mounted on the back surface of the circuit board 1, the lead holes 5 into which the terminal leads 4 are to be inserted by elastic deformation.
Can be backed up in close contact. The electronic component insertion mechanism 10 sequentially inserts the radial lead type electronic components 3 into the upper surface of the circuit board 1 whose back surface is backed up by the sponge-shaped portion 6. In the present embodiment, the electronic component insertion mechanism 10 holds the electronic component 3 received from an electronic component supply mechanism (not shown) while holding the terminal leads 4.
An insertion chuck 11 for introducing the terminal leads 4 to the upper predetermined position, that is, above the lead holes 5 into which the terminal leads 4 are to be inserted, and pressing the head of the electronic component 3 to lead the terminal leads 4 And an insertion head 12 that acts to insert into the hole 5. The tip of the terminal lead 4 inserted into the lead hole 5 as described above and protruding from the back surface of the substrate 1 pierces the sponge-like portion 6 that backs up the back surface of the lead hole 5. Then, the intermediate portion of the lead 4 is connected to the lead hole 5
, And the tip is held by the sponge-like portion 6, thereby preventing the electronic component 3 from falling down. Subsequently, the other electronic components 3 are inserted into the board 1 in the same manner. The previously inserted electronic components are prevented from falling down as described above, Since there is no dead space due to the anvil on the back surface of the substrate 1, the other electronic component 3 can be inserted into a part very close to the previously inserted electronic component without any problem. When all the radial lead type electronic components 3 have been inserted in this way, the holding member 7 is moved down to release the sponge-like portion 6 from holding the tip of the terminal lead 4, and at this time, each of the inserted components is inserted. The electronic component 3 may fall, but since the terminal leads 4 are already inserted into the predetermined lead holes 5 on the substrate, there is no problem in the function of the component or circuit. There is no. The inserted terminal leads 4 are fixed to the substrate 1 in a subsequent step of soldering to the back surface of the substrate 1. FIG. 2 shows an example of a series of working steps of the electronic component mounting method according to the present invention. First, the chip-type electronic component 2 is mounted on both the front and back surfaces of the circuit board 1 (FIG. 2A). in this case,
The chip-type electronic component 2a on the front surface is attached to a predetermined position on the substrate by solder paste, and the chip-type electronic component on the back surface is attached.
2b is temporarily fixed to a predetermined position on the back surface of the substrate by an adhesive. Next, the surface of the substrate is soldered by a reflow soldering method to fix the chip-type electronic component 2a on the surface (FIG. 2 (b)). Next, the radial lead-type electronic components 3 are inserted as described above while backing up the back surface of the substrate with the sponge-like portion 6 (second example).
(C) Finally, a soldering process is performed on the rear surface of the substrate, and the substrate of each of the terminal leads 4 of the chip-type electronic components 2b temporarily fixed on the rear surface and the radial lead-type electronic components 3 projecting on the rear surface is formed. Fix to the back side (2nd
Figure (d). Also, as in another example of the component mounting line shown in FIG. 3, the chip-type electronic components 2a, 2b,... Are fixed to the front and back surfaces of the substrate 1 by the reflow soldering method (FIGS. 3A and 3B). )) Then, the radial lead type electronic components 3 are inserted as described above (FIG. 3 (c)), and the terminal leads 4 projecting from the rear surface of the substrate 1 are soldered by a spot soldering method. You can also do it. As is apparent from a comparison between the conventional component mounting line shown in FIG. 5 and the component mounting lines shown in FIGS. 2 and 3 using the present invention, the number of steps is reduced when the present invention is used. Since the mechanism to flip the substrate is omitted,
The line configuration can be simplified as compared with the conventional case. As a result, the efficiency of the component mounting process is improved, the line configuration cost can be reduced, and handling errors and the like are reduced, and the product quality is improved. Further, since a mechanically relatively complicated anvil including a lead clinch claw is not required, the configuration of the component automatic insertion device itself is also simplified.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing an example of a working process of an electronic component mounting method according to the present invention, and FIG. 2 and FIG. 3 are a series of electronic component mounting methods according to the present invention. FIG. 4 is an explanatory view showing an example of a working process, FIG. 4 is a sectional view showing a conventional example, and FIG. 5 is an explanatory view of a conventional component mounting line on a circuit board. 1 ... circuit board, 3 ... radial lead type electronic component, 4
... terminal lead, 5 ... lead hole, 6 ... sponge-like portion, 7 ... holding member, 10 ... component insertion mechanism.

Claims (1)

(57) [Claims] A step of fixing the electronic component on at least the back surface of the circuit board, and a holding member provided with a sponge-like portion that is elastically deformable and has a constant shape-retaining force, the sponge-like portion being provided on the back surface of the circuit board By abutting, a step of backing up the circuit board, and an electronic component having a terminal lead, inserts the terminal lead into the lead hole of the circuit board from the front side of the circuit board, and inserts the terminal lead into the sponge-like portion. A method for mounting an electronic component, comprising: a step of holding by piercing; and a step of fixing the terminal lead to the circuit board after separating the holding member from the circuit board.