JPH0783933B2 - Circuit board soldering method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for soldering a circuit board on which surface-mounted electronic components are mounted.

(Prior Art) Conventionally, the order of soldering in the process of assembling a hybrid integrated circuit is as follows. First, a surface mounting type flat package IC, a chip resistor, and a chip capacitor are soldered using a solder reflow method, and then, Parts with leads such as aluminum electrolytic capacitors are soldered by the molten solder bath dipping method.

FIG. 2 is a front view showing a conventional soldering device for lead components. In the figure, the soldering device is configured such that a solder bath 1 for storing molten solder, a drive pump 2 for injecting the molten solder, and a melted solder 3 for ejecting by rotation of the drive pump 2 are ejected upward. It is composed of a spout 4 that flows out. The hybrid integrated circuit board 5 has a surface mount type flat package IC 6 on the back surface for forming a circuit, and a chip resistor 7 and a chip capacitor 8 on the front surface, which are already soldered by the solder reflow method. In order to solder the capacitor 9, the lead terminal 9a is inserted through the mounting through hole of the hybrid integrated circuit board 5, and then the molten solder 3 is brought into contact with the capacitor 9 for soldering.

(Problems to be Solved by the Invention) However, in the above configuration, since the flat package IC 6 mounted on the back surface is immersed in the molten solder 3, the solder reflow in the previous process is performed twice in the solder immersion in this process. There was a problem that the reliability of the parts was lowered due to the stress. Further, there is a problem that the leads of the flat package IC 6 are soldered and short-circuited by the second soldering process. The present invention is to solve the above problems, and an object of the present invention is to provide a method for soldering only electronic components with lead terminals without applying thermal stress to surface-mounted electronic components mounted on the lower surface of a circuit board. To do.

(Means for Solving the Problems) In order to solve the above problems, the present invention is to solder a surface mounting type electronic component to a lower surface in advance, and at a plurality of positions other than the area where the surface mounting type electronic component is mounted. A circuit board on which the lead terminals of a plurality of electronic components are inserted from the upper surface side and the plurality of electronic components are mounted, a solder bath for storing molten solder, and a plurality of drive pumps for injecting the molten solder in the solder bath,
The plurality of electrons exposed on the lower surface side of the circuit board are provided on a soldering device including a plurality of jet ports which are respectively communicated with the plurality of drive pumps and arranged corresponding to the positions of the plurality of electronic components. Only the regions of the lead terminals of the component are arranged so as to be respectively immersed in the molten solder that is jetted onto the jet holes.

(Operation) With the above configuration, surface-mounted electronic components that are surface-mounted on the lower surface to be soldered do not undergo solder immersion, and the lead terminals exposed on the lower surface are selectively immersed in solder. The reliability of surface-mounted electronic components can be secured without the risk of heat stress being applied to the mounted electronic components.

(Example) An example of the present invention will be described with reference to FIG. This drawing is a front view of the soldering apparatus according to the present invention. The difference from the conventional example shown in FIG. 2 is that the jet port 4 of the molten solder 3 is inserted into the through hole of the hybrid integrated circuit board 5 and the aluminum electrolytic It is provided at two positions of the lead terminal 9a of the capacitor 9. Since the other components are the same, the description is omitted. The operation of the soldering device configured as described above will be described. First, the chip resistor 7 and the chip capacitor 8 are soldered on the front surface and the surface mount type flat package IC 6 is soldered on the rear surface of the hybrid integrated circuit substrate 5 by the solder reflow method. Next, after inserting the lead terminals 9a of the aluminum electrolytic capacitor 9 into the through holes from the surface of the hybrid integrated circuit board 5, the lead terminals 9a are respectively connected to the molten solder 3 of the two jet ports 4 of the soldering device described above. Immerse and solder. As shown in the figure, the jet port 4 has a lead terminal 9a.
Flat package IC because it is in contact with only
6 does not touch molten solder. As described above, the jet port 4 is set to 2
By dividing into individual pieces, soldering is performed only on the originally necessary parts, and it is possible to prevent unnecessary second heat stress from occurring in the flat package IC6, and it is possible to prevent a short circuit between leads. . In this embodiment, the number of the jet ports 4 is two, but when the number of lead parts to be soldered is more than two, the number may be increased according to the number.

(Effects of the Invention) As described above, according to the present invention, since the jet holes are provided only in the portions required for soldering, surface mounting type electronic components that do not require soldering (for example, flat package ICs) In (), since the thermal stress due to the contact of the molten solder is not given, the reliability of the circuit board on which the electronic component is mounted can be improved.

[Brief description of drawings]

FIG. 1 is a front view of a soldering device of the present invention, and FIG. 2 is a front view of a conventional soldering device. 1 ... Solder tank, 2 ... Drive pump, 3 ... Molten solder, 4
...... Spout hole, 5 ...... Hybrid integrated circuit board, 6 ...... Flat package IC, 7 ...... Chip resistor, 8 ...... Chip capacitor, 9 ...... Aluminum electrolytic capacitor, 9a ...... Lead terminal.

Claims (1)

[Claims] 1. A surface mounting type electronic component is previously soldered to a lower surface, and lead terminals of the plurality of electronic components are inserted from a top surface side into a plurality of positions other than a region where the surface mounting type electronic component is mounted. The circuit board on which the electronic components are mounted, a solder bath for storing the molten solder, a plurality of drive pumps for injecting the molten solder in the solder bath, and a plurality of drive pumps that are respectively connected to the plurality of drive pumps to position the electronic components. On the soldering device consisting of a plurality of jet ports arranged correspondingly, only the areas of the lead terminals of the plurality of electronic components exposed on the lower surface side of the circuit board are jetted onto the plurality of jet ports. A method for soldering a circuit board, wherein the circuit boards are arranged so as to be respectively immersed in the rising molten solder.