JPH0487395A - Soldering - Google Patents

Abstract

PURPOSE:To manufacture a printed board, which is superior in reliability of soldering, by a method wherein a creamy solder is applied on a land and after heat-resistant components are soldered in a reflow furnace, a lead which is a non-heat-resistant component is inserted in a hole formed in the lead and is soldered. CONSTITUTION:A hole 3 for lead insertion use is provided in a land 2 or 5 for non-heat-resistant component mounting use on a printed board 1. A creamy solder 4 or 6 for non-heat-resistant component use and a creamy solder 8 for other component use are printed on the individual lands. The board is made to pass through a reflow furnace 10, the solder 8 is melted in a high-temperature atmosphere, which is produced by heaters 11, and chips components 9 are soldered. The solder 4 or 6 is also melted simultaneously with the solder 8 and is brought into a state that it is applied on the land 2 or 5. An inserted non-heat-resistant component 12 is inverted while being held by a component stopping pin 14 so as not to fall, a soldering bit 15 of a robot is brought into contact with the metal solder 4 or 6 on the land 2 or 5 and a filament solder 16 is fed to complete a soldering of a lead 13 of the component 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a technology for mounting electronic components on the surface of a printed circuit board, and when the reflow method and automatic soldering are used together with the robot method, the quality of soldering can be significantly improved. Effective soldering methods are related to improvements.

Conventional technology In recent years, the soldering process for printed circuit boards used in home appliances has been replaced by the flow method (a method in which the printed circuit board is immersed in a solder bath) in order to achieve higher density mounting, and the reflow method has become popular. It is being used.

The reflow method is a method in which cream solder is printed on a printed circuit board, chip components are mounted, and then the printed circuit board is placed in a reflow oven (high temperature furnace) to melt the cooled solder and solder the chip components.

However, it is impossible to use the reflow method for all parts due to heat resistance, so non-heat resistant parts are soldered by hand after flow soldering is completed.

When performing this soldering, in recent years, in order to promote greater automation, soldering is generally performed by a robot rather than by hand.

Problems to be Solved by the Invention However, in this robot soldering, the printed circuit board beams are passed through a flow furnace in the previous process and exposed to high temperatures (240°C).
), and the soldering of the printed circuit board (soldering is done by robots and is done in a remote area, copper foil is usually used) becomes oxidized, and the soldering becomes worse. However, there is a problem in that soldering tends to be defective during the manufacturing process. In particular, compared to manual soldering, soldering by robots is controlled by certain programmed data, so if the conditions for soldering the printed circuit board material are not consistent, there will be many soldering defects. There are some issues.

The present invention solves the above problems, and aims to provide a soldering method that can manufacture printed circuit boards with excellent soldering reliability.

Means for Solving the Problems In order to achieve the above object, the present invention applies cream solder to a land having a hole into which a lead of a non-heat resistant component is inserted,
When heat-resistant parts are mounted, this cream solder is simultaneously melted in a reflow oven and the lands are coated with solder.

Therefore, according to the present invention, by coating the lands to which leads of non-heat resistant parts are soldered with melted cream solder in advance, oxidation of the surface of the lands can be prevented and high-quality soldering can be achieved. Good soldering can give you reliability.

At this time, if cream solder is applied to the entire land, the solder will flow into the hole where the lead of the component is inserted, causing hole clogging, so apply cream solder in a special shape.
Soldering improves properties and at the same time prevents hole clogging due to solder.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. In the figure, 1 is a printed circuit board, 2 is a land having a hole 3 for inserting a non-heat resistant component, and the surface of the printed circuit board 1 is made of copper. It is made of foil or the like, and a plurality of circular cream solders 4 are printed and coated on its surface. FIG. 2 shows the structure of another embodiment of the present invention, which differs from the previous embodiment in that when the shape of the runt 5 changes, the shape of the cream solder 6 also changes.

Next, a method for soldering electronic components and the like to the printed circuit board 1 will be explained using the above embodiment.

Fig. 3 (fat to if) is a schematic diagram of the main part showing the soldering method of this embodiment. A hole 3 for inserting a lead is provided in a runt 2 or 5 for mounting a non-heat-resistant component on a printed circuit board 1 having a land 7 for other components. Next, as shown in tb+ in the figure, cream solder 4 or 6 for non-heat resistant parts and cream solder 8 for other parts are printed on the respective lands. In the same figure (C), other components 9 (heat-resistant chip components, etc.) are mounted on this cream solder 8 for other components using a mounting machine.
The printed circuit board 1 on which the chip components 9 and the like are mounted is passed through a reflow oven 10 as shown in the same figure (di), and the cream solder 8 is melted in a high temperature (240° C.) atmosphere with a heater 11. Solder the chip component 9.

At this time, cream solder 4 or 6 for non-heat-resistant parts is also melted and placed on land 2 or 5 at the same time.

(e) Printed circuit board 1 passed through beam flow furnace 10
Figure (f) shows a state in which the lead 13 of the non-heat resistant component 12 is inserted into the hole 3 for inserting the component.
As shown in , the inserted non-heat resistant component 12 is held with the component holding pin 14 to prevent it from falling, and then turned over. For soldering, the robot's half-day iron 15 is applied to the molten cream solder 4 on land 2 or 5. 6 and supplying thread solder 16 to complete the soldering of the lead 13.

In FIG. 1, when the land 2 is a round type copper foil pattern (diameter 2.5 mm), the lead 13 insertion hole 3 (
0.8 m in diameter), and as shown, cream solder 4 with a diameter of 0.4 mm is printed at four locations at angles of 90 degrees.

The most desirable size of the cream solder 4 is the ratio of land diameter to hole diameter minus 621 of the ream solder diameter.

In addition, in FIG. 2, when the land 5 is an oval type copper foil pattern (1.4 mm x 2.0 m), the cream solder 6 (0 m , 3mm x 0.5mn+) are printed in two places on the left and right sides of the hole 3.

As described above, according to the above embodiment, the cream solder 4 or 6 is printed and soldered on the land 2 or 5 having the hole 3 into which the lead 13 of the non-heat resistant component 12 is inserted. Soldering provides reliability.

The cream solder 4.6 having a special shape as shown in FIGS. 1 and 2 is printed in a flow furnace 10- as shown in FIG. 3 (fd). This is to prevent the melted solder 4.6 from flowing into the hole 3 into which the lead 13 of the non-heat resistant component 12 is inserted when it melts.

Effects of the Invention As is clear from the above embodiments, in the present invention, cream solder is printed and coated in a certain shape in advance on the lands to which the leads of non-IT thermal components are soldered. When soldering in a reflow oven, the cream solder melts and coats the land, so the surface of the land, which is made of copper foil, will not be oxidized.

In addition, since the land is coated with solder, when thread solder is supplied, the land part of the copper foil etc. to be soldered has very good solder wettability, and a uniform amount of solder is formed and soldered at the same time. The result is a dramatic improvement in quality.

[Brief explanation of the drawing]

FIG. 1 is an enlarged plan view of the main parts of a printed circuit board according to an embodiment of the present invention, FIG. 2 is an enlarged plan view of the main parts of a printed circuit board according to another embodiment of the invention, and FIG. 1 is a schematic process diagram showing the configuration of a soldering method according to an embodiment of the present invention. 1... Printed circuit board, 2.5... Land, 3... Hole. , 4.6... Cream solder, 7... Other lands, 9... Other electronic parts (chip parts), 10... Reflow oven, 12...Non-heat resistant parts, 13...
Lead. Name of agent Patent attorney Shigetaka Awano (1 person) Figure 1 Print 1 & 5 Rim Ikuta

Claims (1)

[Claims] After forming a hole for inserting a lead into the land of a printed circuit board having a land made of copper foil or the like on which a non-heat resistant component is to be mounted, cream solder is applied on the land, and the other land parts are mounted with the chip component. A soldering method in which heat-resistant components such as the above are soldered in a reflow oven, and then the leads of the non-heat-resistant components are inserted into the holes and soldered.