JPH02192792A - Method of soldering electronic component with low thermal resistance - Google Patents

Abstract

PURPOSE:To enable an electronic component with low thermal resistance to be soldered automatically by passing a lead terminal through a through hole so as to be in contact with a pad of a circuit pattern on the opposite side of a board and exposing it to jets of solder. CONSTITUTION:A through hole 14 is formed in a circuit board P such that the hole is extended from one face to the other of the board. Terminals 15a, 15b of an electronic component 15 are in contact with pads 13 through a low-melting solder 17. The solder 17 is deposited on the pads 13 by a screen printing process. A lead terminal 18a of the electronic component 18 is passed through the hole 14 and the tip end thereof is in contact with a pad 13 on the opposite face of the board P. The circuit board P is moved in the direction as indicated by the arrow so that the opposite face of the board is brought into contact with jets of solder. In this manner, even an electronic component 18 having low thermal resistance can be soldered automatically. Further, even if an electronic component with higher thermal resistance is to be soldered togethar with such component with low thermal resistance, they can be soldered automatically in a single process. Consequently, the working efficiency can be improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for soldering low heat resistant electronic components to metal-based circuit boards.

[Prior Art] Conventionally, when soldering electronic components to a metal base circuit board, an insulating resin layer 2 is formed on a metal plate 1 as shown in FIG. A cream solder layer 4 is formed by screen printing on the pad portion 3 of a metal base circuit board in which a circuit pattern and a pad portion 3 are formed on the resin layer 2, and a heat-resistant electronic component 5 is formed on the solder layer 4.
The heat-resistant electronic component 5 is bonded and fixed to the metal base circuit board with an adhesive 6, and in this state, the metal base circuit board is passed through an infrared reflow oven or a hot air reflow oven to melt the cream solder layer 4. The terminals of the electronic component 5 are bonded to the pad portion 3 by using the pad portion 3.

Then, as shown in FIG. 3(b), another pad part 3
The lead terminals of the low heat resistant electronic component 7 were manually joined using a trowel for half a day.

[Problem 8 to be solved by the invention] Conventionally, when fixing low heat resistant electronic components to a circuit board, an infrared reflow oven or a hot air reflow oven cannot be used because the electronic components will be damaged by heat. However, everything had to be done manually, which was a hassle. Therefore, when soldering both heat-resistant and low-heat-resistant electronic components to a circuit board, there are two steps: automatic soldering of the heat-resistant electronic components and manual soldering of the low-heat-resistant electronic components. There was a problem that required two steps.

Therefore, the present invention can automate the soldering of low heat resistant electronic components to metal-based circuit boards. Therefore, even if low heat resistant electronic components and heat resistant electronic components are mixed, the soldering work can be completed in one step. It is an object of the present invention to provide a method for soldering electronic components with low heat resistance, which makes it possible to improve work efficiency.

[Means and effects for solving the problem] The invention as claimed in claim (1) provides that when a low heat resistant electronic component is soldered to a metal base circuit board, the low heat resistant electronic component is soldered to one side of the circuit board. While fixing with adhesive, the lead terminal of the low heat resistant electronic component is brought into contact with the pad part of the circuit pattern provided on the other side of the circuit board through the through-hole part made in the circuit board, and in this state, the circuit board is The purpose is to solder the lead terminal of a low heat resistant electronic component to the pad portion of the circuit pattern by bringing a solder jet into contact with the other side. Therefore, if heat-resistant electronic components are also present, it is possible to adhesively fix the heat-resistant electronic components to one side of the circuit board and contact the lead terminals with the pads via low-melting-point solder. This melts the solder and allows simultaneous bonding of heat-resistant electronic components.

Furthermore, the invention as claimed in claim (2), when soldering a low heat resistant electronic component to a metal base circuit board, adhesively fixes the low heat resistant electronic component to one side of the circuit board, and The lead terminals are brought into contact with the pads of the circuit pattern provided on one side of the circuit board via low melting point solder, and in this state, a liquid heat medium jet is brought into contact with the other side of the circuit board to achieve low heat resistance. The purpose is to solder the lead terminals of electronic components to the pads of the circuit pattern. That is, the solder is melted by the heat of the liquid heat medium jet, and the low heat resistant electronic component is bonded to the pad portion.

This also makes it possible to bond heat-resistant electronic components in the same way.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 11 is a metal plate, and insulating resin layers 12a and 12b are formed on both sides of this metal plate 11, respectively, and a circuit pattern and a pad part 13 are further formed on the insulating resin layers 12a and 12b. It constitutes a base circuit board P.

Further, the circuit board P is provided with a through hole portion 14 extending from one side to the other side, and this through hole portion 1
4 is also formed with a pad portion 13.

Then, a heat-resistant electronic component 15 is adhesively fixed to one side of the circuit board P using an adhesive 16, and the terminal portions 15a and 15b of the electronic component 15 are connected to the pad portion 13 with a cream solder 17, which is a low melting point solder, in between. is in contact with. Note that the cream solder 17 is laminated on the pad portion 13 by screen printing.

Also, a steel capacitor is installed on one side of the circuit board P.
Low heat resistant electronic components such as P capacitors and electrolytic capacitors 1
8 with adhesive 16 and the electronic component 1
The lead terminal 18a of No. 8 is passed through the through-hole portion 14 and its tip portion is brought into contact with the pad portion 13 provided on the other side.

Note that another heat-resistant electronic component 19 is adhesively fixed to the other side of the circuit board P with an adhesive 16, and its terminal portion 1
9a and 19b are in contact with the pad portion 13.

With the low heat resistant electronic component 18 and the heat resistant electronic component 15, 19 adhesively fixed onto the metal base circuit board P in this manner, the circuit board P is moved in the direction shown by the arrow in the figure, and the circuit board P is moved in the direction shown by the arrow in the figure. The other side of the substrate P is brought into contact with the solder jet.

Thus, the tips of the lead terminals 18a of the low heat resistant electronic component 18 are joined to the pad portions 13 by solder. In addition, the terminal portions 19a and 19b of one heat-resistant electronic component adhesively fixed to the other side of the circuit board P are also soldered to the pad portion 1.
3.

Further, regarding the heat-resistant electronic component 15 adhesively fixed to one side of the circuit board P, the cream solder 17 melts as the heat of the solder jet is transmitted through the metal plate 11.
The terminal portions 15a and 15b are joined to the pad portion 13.

In this way, by moving the circuit board P while bringing the solder jet into contact with the other side, both the low heat resistant electronic components 18 and the heat resistant electronic components 15 and 19 can be automatically soldered at the same time. In other words, soldering can be automatically completed in one step. Therefore, work efficiency can also be improved.

Next, other embodiments of the present invention will be described with reference to the drawings. Note that the same parts as in the above embodiment are given the same reference numerals and detailed explanations will be omitted.

As shown in FIG. 2, a metal base circuit board P on which an insulating resin layer 12a is formed only on one side and a pad portion 13 formed thereon is used. The part is brought into contact with the pad part 13 via cream solder 17. Note that no electronic components are provided on the other side of the circuit board P.

Even if electronic components are bonded and fixed only to one side of the circuit board P, the heat from the solder jet can be absorbed by bringing the other side of the circuit board P into contact with the solder jet, which is a jet of liquid heat medium. is transmitted through the metal plate 11 and the cream solder 1
7 is melted, both the low heat resistant electronic component 18 and the heat resistant electronic component 15 can be soldered at the same time in this embodiment as well, and the same effects as in the previous embodiment can be obtained.

In this embodiment, since there are no parts to be soldered on the other side of the circuit board P, there is no need to use a solder jet as the liquid heat medium jet, and even if a heated silicone oil jet or the like is used, for example. good.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to automate the soldering of low heat-resistant electronic components to a metal-based circuit board,
Therefore, even if low heat resistant electronic components and heat resistant electronic components are mixed, it is possible to complete the soldering work in one step, and it is possible to provide a method for soldering low heat resistant electronic components that can improve work efficiency. be.

[Brief explanation of the drawing]

FIG. 17 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG. 3 is a diagram for explaining the conventional soldering process. P... Metal base circuit board, 13... Pad part, 1
4...Through hole part, 16...Adhesive, ]7...
・Cream solder, 18...Low heat resistant electronic components. Applicant's agent Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) When soldering a low heat resistant electronic component to a metal base circuit board, the low heat resistant electronic component is adhesively fixed to one side of the circuit board, and the lead terminal of the low heat resistant electronic component is connected to the circuit board. The circuit board is brought into contact with the pad part of the circuit pattern provided on the other side of the circuit board through the through hole part opened in the circuit board, and in this state, the solder jet is brought into contact with the other side of the circuit board, thereby reducing the low heat resistance. A method for soldering low heat resistant electronic components, characterized by soldering lead terminals of electronic components to pads of a circuit pattern. (2) When soldering a low heat resistant electronic component to a metal base circuit board, the low heat resistant electronic component is adhesively fixed to one side of the circuit board, and the lead terminal of the low heat resistant electronic component is connected to the circuit board. The leads of the low heat resistant electronic component are brought into contact with the pad portion of the circuit pattern provided on one side of the circuit board via a low melting point solder, and in this state, the other side of the circuit board is brought into contact with a liquid heat medium jet. A method of soldering low heat resistant electronic components, characterized by soldering terminals to pads of a circuit pattern.