JPH11274710A - Mounting method for electronic part and solder solid matter used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for mounting an electronic part on a print substrate, particularly on a high-density substrate and other substrates, so as to prevent the release of solder and to positively mount the electronic part in a relatively simple process. SOLUTION: A mounting method is for mounting an electric part 30, which has lead terminals 31 inserted into through holes 12, onto a print substrate 10. In this case, solder solid matters 1 are used. The solder solid matters 1 are provided with axis-solder parts which are inserted into the through holes 12, and brimmed parts, each being integrally disposed at an upper part of the axis-solder part with a diameter larger than that of the through hole 12. Further, the axis-solder parts are inserted into the through holes 12, and the solder solid matters 1 are melted so as to solder the lead terminals 31 under the condition where the lead terminals 31 are inserted through the centers of the solder solid matters 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting electronic components on a printed circuit board, particularly a high-density mounting board.

[0002]

2. Description of the Related Art The mounting of electronic components on a printed circuit board is generally performed as follows. First, a solder paste is printed at an appropriate position on the upper surface of the substrate, a reflow component is mounted on the solder paste, and is passed through a reflow furnace, and the solder paste is melted, and the reflow component is soldered and mounted on the substrate ( "Reflow process").

[0003] Further, a lead component to be fixed by inserting a lead terminal into a through-hole provided in a substrate is provided by mounting the lead component on the substrate after the reflow process, and inserting the lead terminal into the through-hole to form a back surface of the substrate. To the side. The through-hole component is fixed by applying a varnish to the substrate and applying a molten solder having a lower melting point than the solder paste through a dip tank (referred to as a “flow process”).

[0004]

In the above-mentioned conventional mounting method, a flow process for resolving the solder on the substrate after the reflow process has to be performed, so that two types of solder having different melting points are required. And the process becomes complicated. In order to solve this problem, a method has been proposed in which solder for lead components is also printed at the time of solder paste printing for the reflow process, the reflow component and the lead component are simultaneously mounted on a substrate, and the substrate is passed through a reflow furnace. (See JP-A-9-219581).

However, in the method of printing solder for lead components at the time of printing the solder paste for the reflow process, when the diameter of the through hole is large, the viscosity of the solder paste is low, so that the stability of the solder on the through hole is low. There is a possibility that the solder amount required for mounting may not be secured. In addition, the solder for the through-hole may deviate, get stuck between other component terminals, and cause a so-called solder bridge that short-circuits between the component terminals via the solder. Further, even when the lead component is inserted, it is conceivable that a part of the solder may be removed and scattered to the other part, so that the same problem as described above may occur.

An object of the present invention is to solve such a problem of the conventional electronic component mounting method and to make it possible to mount the electronic component reliably by a relatively simple process.

[0007]

According to the present invention, there is provided a method of mounting an electronic component having lead terminals inserted into a through hole of a printed circuit board on the printed circuit board. Using a solid solder having a shaft solder portion to be fitted and a flange portion larger than the diameter of the through hole and integrally provided at an upper end portion of the shaft solder portion, through the shaft solder portion, The method is characterized in that the solder solid is melted and soldered to the lead terminal in a state where the lead is inserted into the hole and the lead terminal of the electronic component is inserted through the center of the solid solder.

According to this mounting method, the through-hole component can be mounted on the substrate at the same time as the other electronic components, and the soldering process can be performed at the same time. In this case, since the solder for the lead component is fitted in the through-hole, there is no possibility that the solder will deviate halfway, and the required amount of solder can be secured and the electronic component can be securely fixed.

In this method, either the fitting of the shaft-shaped solder portion into the through-hole of the printed circuit board or the insertion of the lead terminal into the solid solder may be performed first.

That is, the solid solder is mounted on a printed circuit board by a jig so that the shaft-shaped solder portion fits into the through hole, and then the electronic component is mounted on the printed circuit board to form the electronic component. The lead terminal is inserted into the center of the solder solid, and then the solder solid is melted in a reflow furnace. Alternatively, a part of the solder solid is welded to the lead terminal with the lead terminal inserted through the center of the solder solid, thereby fixing the solder solid to the lead terminal of the electronic component. The components may be mounted on a printed circuit board, and the lead terminals and the solid solder solid portion fixed to the lead terminals may be fitted into the through holes, and then the solid solder may be melted in a reflow furnace.

The solder solid includes a shaft-shaped solder portion fitted into a through-hole of a printed circuit board, and a flange portion which is larger than the diameter of the through-hole and integrally provided at an upper end of the shaft-shaped solder portion. By having a through hole for inserting a lead terminal in the center portion while being provided, it is effectively applied to the above mounting method.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a solder solid 1 used in the mounting method of the present invention. The solder solid 1 is entirely formed of solder, and a flange 3 having a larger diameter than the shaft 2 is integrally formed at the upper end of a shaft (shaft-shaped solder) 2. The upper part of the shaft part 2 is formed as a smooth curved surface part 4 whose diameter gradually increases, and is loosely connected to the collar part 3.

Further, at the center of the solder solid 1,
Vertical through holes 5 through which lead terminals of lead components are inserted
Is provided. The upper part of the through hole 5 is spread in a mortar shape, so that the lead terminal can be easily inserted.

The length of the shaft portion 2 of the solid solder 1 in the illustrated example is substantially equal to the thickness of the printed circuit board on which the electronic components are mounted. This length may be optimized depending on the thickness of the lead terminal, the diameter of the through hole, the thickness of the printed circuit board, and the like. If the length is too short, the amount of solder may be insufficient and the lead terminals may not be sufficiently fixed. On the other hand, if the length is too long, there is a possibility that the molten solder may be dropped.

The method of using the solder solid 1 is as follows. First, in the first method, as shown in FIG. 2, the shaft portion 2 of the solid solder 1 is pressed into the position of the through hole 12 of the printed circuit board 10 on which the copper wiring pattern 15 is printed. Thus, the solid solder 1 is mounted on the printed circuit board 10. In this case, the flange portion 3 remains on the upper surface of the substrate and serves to hold the shaft portion 2.

FIG. 2 shows how the solder solid 1 is pushed in.
It is convenient to use a pushing jig 20 as exemplified in FIG. As the jig 20, it is preferable to use a jig that sucks and holds a solder solid by a vacuum suction type or a jig that can hold and hold a solder solid by a nail in a chuck type. Incorporating the pressing work with this jig into the component mounter and mounting the solder solids at the same time as the mounting of the chip components allows the work to be performed without extra steps, so it is efficient. is there.

As described above, the lead component 30 is mounted on the printed board 10 on which the solder solid 1 is mounted, and the lead terminal 31 is inserted into the center of the solder solid 1. In this state, when passing through a reflow furnace,
Is melted, and the lead component 30 is mounted on the printed circuit board 10 by soldering.

FIG. 3 shows a method of use different from that described above. In the illustrated example, the lead terminal 31 of the lead component 30 is inserted into the through hole 5 of the solder solid 1 in advance.
In this state, the vicinity of the base of the shaft portion 2 or the brim portion 3 is heated by using a soldering iron 35 to melt a part of the solid solder 1 and weld it to the lead terminal 31. Thereby, the solid solder 1 is securely fixed to the lead terminal 31. The upper and lower positions of the solder solids 1
Is located on the printed circuit board component surface land. Then, when the lead component 30 is mounted on the printed circuit board 10 and the lead terminal 31 is inserted into the through hole 12, the shaft portion 2 of the solid solder 1 also fits into the through hole 12. Thereafter, by passing through a reflow furnace, the solder of the solder solid 1 is melted, and the lead component 30 is soldered and mounted on the printed circuit board 10.

In the case of this method as well, if the mounting of the solid solder 1 is incorporated into the operation of the chip mounting machine and the mounting of the solid solder is performed simultaneously with the mounting of the chip, the operation can be performed without any extra steps. Since it can be performed, it is efficient, and it is possible to reduce the number of solder visual inspection steps.

According to the mounting method of the present invention, reflow can be performed irrespective of the diameter of the through hole, and the present invention can be applied to a through hole having a large diameter. Even in a semiconductor or the like, mounting can be performed in a reflow process without passing through a flow process.

[0022]

As is apparent from the above description, according to the present invention, it is possible to mount lead components in a reflow process regardless of the diameter of a through hole.
Since a flow step is not required, manufacturing efficiency can be improved. In addition, since the solder is unlikely to be scattered at the time of mounting, it is possible to effectively prevent a problem such as a conventional solder bridge.

[Brief description of the drawings]

FIG. 1 is an external view of a solder solid suitable for use in carrying out the mounting method of the present invention.

FIG. 2 is an explanatory diagram of its usage.

FIG. 3 is an explanatory diagram of a usage different from the above.

[Description of Signs] 1 Solder solid 2 Shaft 3 Collar 5 Through hole 10 Printed circuit board 12 Through hole 30 Lead component 31 Lead terminal

Claims (4)

[Claims] 1. A method for mounting an electronic component having a lead terminal inserted into a through hole of a printed circuit board on the printed circuit board, the method comprising: mounting a shaft-shaped solder portion fitted into the through hole; Using a solder solid having a flange portion integrally provided at the upper end of the shaft solder portion, the shaft solder portion is fitted into a through hole, and a center portion of the solder solid material is used. And mounting the lead terminal by melting the solid solder while the lead terminal of the electronic component is inserted through the lead terminal. 2. The solder solid is mounted on a printed circuit board by a jig so that the shaft-shaped solder portion fits into the through hole, and the electronic component is mounted on the printed circuit board. 2. The electronic component mounting method according to claim 1, wherein the lead terminal is inserted into the center of the solder solid, and then the solder solid is melted in a reflow furnace. 3. A part of the solder solid is welded to the lead terminal in a state where the lead terminal is inserted through the center of the solder solid, thereby fixing the solder solid to the lead terminal of the electronic component. The electronic component is mounted on a printed circuit board, and a lead terminal and an axial solder portion of the solid solder fixed to the lead terminal are fitted into the through hole, and thereafter, the solid solder is melted in a reflow furnace. The electronic component mounting method according to claim 1. 4. An axial solder portion fitted into a through hole of a printed circuit board; and a flange portion larger than the diameter of the through hole and integrally provided at an upper end of the axial solder portion. A solid solder having a through hole for inserting a lead terminal in a portion.