JP2543844B2 - Electronic component soldering method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for soldering an electronic component to a printed circuit board.

(Prior Art) Conventionally, as a method of mounting an electronic component on a printed circuit board, a through hole is provided in the printed circuit board, a terminal of the electronic component is inserted into the through hole, and soldering is performed from a back surface different from the electronic component mounted product. After that, the resin case of the terminal parts is improved in heat resistance and moisture resistance, and in order to improve the component mounting efficiency such as double-sided mounting of electronic components on the printed circuit board, it is possible to pass through the printed circuit board. A surface mounting method has been implemented in which the terminals are fixed directly to a wiring pattern on the surface of a substrate on which electronic components are mounted without providing holes. In the soldering of electronic components in this surface mounting method, the electronic components are temporarily fixed to the printed circuit board with an adhesive or the like, and then the printed circuit board is moved directly in the solder bath while directly immersed in the solder solution. Soldering to terminals.

(Problems to be Solved by the Invention) However, in the conventional method of directly immersing the printed circuit board on which the electronic component is mounted in the soldering solution and soldering as described above, as shown in FIG. Small outline package (hereinafter simply referred to as SOP) 3 that includes a resin case 1 that is resistant to moisture and moisture, and a plurality of terminals that are formed on both sides of the resin case as flat surfaces whose ends are easily joined to a printed circuit board 3 When is mounted, soldering failure is likely to occur. As shown in FIG. 3, when the SOP3a is mounted so that the terminal group is arranged at right angles to the moving direction A of the printed circuit board 4 in the solder bath, the terminal group on the side where the solder solution flows Since excess solder cannot escape sufficiently in 2a, a solder bridge occurs due to excess solder, and in the other terminal group 2b, SOP3a hinders the flow of solder,
This is because unsoldered portions are generated without the solder being attached.
Even if the terminal group is the SOP3b arranged in parallel with the direction of the arrow A, if the SOP3a temporarily fixed in the right-angled direction immediately before is present, the flow of the solder solution is blocked by the SOP3a and the unsoldered portion is Because it will occur.

So, in the past, the condition of the soldering device was set for each situation by looking at the layout of SOP3 on the printed circuit board.
This condition setting is troublesome, and generally, there are many variations in the mounting state, which causes a decrease in reliability and an increase in assembly cost due to a post-process such as correction of soldering.

(Means for Solving Problems) In the present invention, when soldering an electronic component such as an SOP including a resin case and terminals to a printed circuit board by surface mounting, a terminal array of all electronic components is provided on the printed circuit board. The terminals are arranged in parallel with each other, and the terminal row of the electronic component on the rear side and the resin case of the electronic component on the front side do not overlap with each other when viewed from the terminal row direction, and are arranged in the solder bath in parallel with the terminal row direction and the terminals. The printed circuit board is moved in a direction in which the terminal row of the electronic component on the rear side and the resin case of the electronic component on the front side do not overlap with each other when viewed from the row direction, and soldering is performed.

(Operation) According to the present invention, all the electronic components are arranged on the printed circuit board so that the terminal row directions are parallel to each other, and the electrons in the solder bath are parallel to the terminal row direction and rearward of the electrons when viewed from the terminal row direction. By moving the printed circuit board in the direction in which the terminal row of the component and the resin case of the front electronic component do not overlap, the solder liquid will flow in the direction in which the terminals of the electronic component are arranged, and the electronic component Uniform soldering is performed on each terminal without obstructing the flow.

(Embodiment) FIG. 1 is a plan view showing an embodiment of the present invention.

In FIG. 1, reference numeral 3 denotes an electronic component, and as shown in FIG. 2 and described above, a printed wiring pattern which is connected to the electronic circuit at both ends of a resin case 1 having a built-in electronic circuit and having heat resistance and moisture resistance. Shows an SOP having a plurality of terminals 2 connected on the component mounting surface. A plurality of SOP3 are temporarily fixed on the printed board 4 with an adhesive or the like.

Here, all the SOP3 terminals 2 on the printed circuit board 4
Are mounted in an array so that they are parallel to each other in the same direction. Furthermore, when viewed from the above direction, the arrangement is such that the terminals of SOP3d are located on the extensions of the terminals 2c of SOP3c.

The printed circuit board 4 on which the SOPs 3 are arranged as described above is dipped in a solder bath and moved in the direction of arrow A, which is the direction in which the rows of the terminals 2 are lined up, to perform soldering.

 FIG. 4 is a plan view showing another embodiment of the present invention.

In FIG. 4, all SOP3 terminals 2 are arranged in parallel in the same direction. Also, SOP3 'is smaller than other SOP3, and when viewed from the B direction, terminal 2'of SOP3' on the rear side and SOP3 on the front side
The arrangement is such that the resin case of e overlaps. Also, S
OP3f is arranged so that its terminal 2f does not overlap with the SOP3g in the front and back.

The printed circuit board 4 on which the SOPs 3 are arrayed as described above is dipped in a solder bath, and when viewed in the direction parallel to the direction in which the terminals 2 are lined up, the terminals overlap the resin case of another electronic component. The electronic component 3'is moved in the forward direction, that is, in the direction of arrow C.

Even if the SOPs are not regularly arranged in the front, rear, left, and right as in the above two embodiments, the SO seen from one side of the terminal row
If the terminal row of the rear electronic component and the resin case of the front electronic component do not overlap with each other in P, the rules of front, rear, left, and right in the arrangement do not matter.

Further, in the present embodiment, the printed circuit board is moved in the solder bath, but the solder solution may be flown without moving the printed circuit board, or the solder solution may be flowed while the printed circuit board is moved. That is, it suffices that relative movement occurs between the printed circuit board and the solder liquid.

(Effect of the Invention) As described in detail above, according to the present invention, the terminals of all electronic components are arranged in parallel in the same direction on the printed circuit board, and the printed circuit board is arranged in the solder bath in the terminal row. In parallel with the direction of this terminal row, when viewed from this terminal row direction, the terminal row of the electronic component on the rear side and the resin case of the electronic component on the front side are moved in such a direction that they do not overlap, so that the solder liquid will flow along the alignment of the terminals, There is no soldering failure such as excess solder pooling to form a solder bridge, or electronic components obstructing the flow of solder liquid to form unsoldered portions.

Therefore, the soldering quality is stable, the post-process of correcting the soldering failure is unnecessary, the assembly cost can be reduced, and the soldering reliability is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an embodiment of the present invention, FIG. 2 is an enlarged perspective view showing electronic components mounted on a printed circuit board, and FIG.
FIG. 4 is a plan view showing a conventional embodiment, and FIG. 4 is a plan view showing another embodiment of the present invention. 2 ... Terminal part, 3 ... SOP, 4 ... Printed circuit board.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-197897 (JP, A) Actually opened 57-132481 (JP, U) Actually opened 60-30566 (JP, U)

Claims (1)

(57) [Claims] 1. A printed circuit board is mounted with an electronic component including a case containing an electronic circuit and a terminal connected to the electronic circuit and connected to a printed wiring pattern on a component mounting surface. The printed circuit board is used as a solder bath. In a method of soldering an electronic component, which is soaked and relatively moved between a solder liquid and a printed circuit board for soldering, in which the terminal row directions of all the electronic components are arranged in parallel on the printed circuit board, and the terminal row direction is The electronic components are mounted in such an arrangement that the terminal row of the electronic components on the rear side and the case of the electronic component on the front side do not overlap each other, and the relative movement direction between the printed circuit board and the solder liquid in the solder bath is set in the terminal row direction. A method for soldering an electronic component, characterized in that the terminal line of the electronic component behind and the case of the immediately preceding electronic component do not overlap each other in parallel to the direction of the terminal column.