JP2020017598A - Board soldering method - Google Patents

Abstract

To solve a problem in which, in a case in which a lead wire is soldered to a land with a through hole in the center, when soldering is performed with an automatic machine having a gate-shaped iron tip, legs formed on both ends of the gate must be in contact with the land, and for this reason, even when the thread-shaped solder fed to the gate-shaped iron tip melts, the molten solder does not flow into a portion where the legs are in contact, and the portion where the legs are in contact is exposed without being covered with solder when the iron tip is removed.SOLUTION: A cream solder is put on an end of a land having a through hole, and is melt due to temporarily heating to form a pre-soldering portion, and a thread-shaped solder and the solder in a pre-soldered portion are mutually melted and integrated when soldering is performed with the above automatic machine.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method of soldering a substrate, which is performed by using a thread-like solder and then by an automatic machine after soldering using cream solder.

  When soldering electronic components to a board, in the case of chip-shaped electronic components, cream solder is applied to conductive lands provided on the surface of the board without providing through holes in the board, and the applied cream is applied. The entire substrate is heated while the electrode portions of the chip-shaped electronic components are placed on the solder. Then, the cream solder is melted and the electrode portions of the chip-shaped electronic component are soldered to the lands.

  On the other hand, when soldering an electronic component having a lead wire to a substrate, a through hole is provided in the center of the land, the lead wire of the electronic component is inserted into the through hole, and the inserted lead wire is inserted. Solder to land. At the time of this soldering, soldering may be performed manually, but may be performed by an automatic machine. When soldering with this automatic machine, the tip of the iron is formed in a gate shape so that the molten solder does not spread to other parts and short-circuit failures occur, etc. Is positioned, and in this state, a thread-like solder is fed into the recess, and the thread-like solder is melted in the gate-shaped recess, thereby soldering the lead to the land (for example, see Patent Document 1).

JP 2002-66733 A (FIG. 6)

  In the case of the soldering by the automatic machine, since the iron tip formed in the gate shape has to transmit heat to the land, it is necessary to directly contact the land. Therefore, the pair of legs sandwiching the recess of the iron tip must directly contact the land. However, when the leg directly contacts the land as described above, even if the thread-like solder fed into the recess is melted, the molten solder does not flow into a portion where the leg and the land are in contact. For this reason, when soldering is performed by an automatic machine, a portion where the leg portions are in contact is not soldered, and there is a problem that the land is exposed.

  In order to prevent such adverse effects, for example, by setting the heating temperature of the iron tip to a high temperature, the solder is melted even after the iron tip is separated from the land, and the molten solder is in contact with the legs. It is also conceivable to apply solder to the entire land by flowing over the part where the solder has flowed. However, when the temperature of the iron tip is increased, the life of the iron tip is shortened, and new problems such as detachment of the land from the substrate and damage of the electronic components due to heat are undesirably caused.

  In view of the above problems, it is an object of the present invention to provide a method of soldering a board that can be soldered onto the entire land even when soldering is performed by an automatic machine.

  In order to solve the above problems, the method of soldering a substrate according to the present invention includes a land having a through hole and a land having no through hole on the substrate surface, and placing cream solder on a land having no through hole, After the electronic component is placed on the cream solder and heated to melt the cream solder and solder the electronic component to a land that does not have a through hole, the lead wire inserted into the through hole is passed through. In a method of soldering a board to be soldered by an automatic machine using a thread-like solder to a land having a hole, in a step of applying cream solder to a land having no through-hole, the land having the through-hole A cream solder is put on the end, and the cream-like solder is melted in the heating step to form a pre-soldering part. When soldering with the automatic machine, a thread-like solder is used. Mutually melted and solder Purehanda unit is characterized in that by integrating them.

  By forming the pre-soldering part in advance on the part that is not soldered with the conventional automatic machine, the melted thread-like solder by the automatic machine and the melted solder piled up in the pre-soldering part are integrated. Thus, the entire land can be covered with solder. Since this pre-soldering portion is formed at the same time as the soldering of the electronic component by the cream solder, it is not necessary to add a new process.

  By the way, when forming the pre-soldering portion, cream solder is applied to the lands, and it is necessary that the applied solder is melted, so that the solder that has melted the through holes formed in the lands is not blocked. . Therefore, it is desirable that a portion where no creamy solder is applied is left between the creamy solder applied to the end of the land having the through hole and the through hole.

  If the land provided with the through hole is made small, the tip of the iron does not contact the land, and the land cannot be sufficiently heated by the tip of the iron. Conversely, if the lands are made larger, the distance between the lands becomes narrower, and a solder bridge is formed, which causes a short circuit failure. Therefore, the iron tip used when soldering with the automatic machine is formed in a gate shape, and is configured to supply the thread-like solder to a concave portion sandwiched between a pair of legs of the gate shape. The above-mentioned land is extended on both sides of the through-hole, the cream solder is piled on the extended portion, and the leg of the iron tip is brought into contact with the pre-solder portion where the cream solder is melted, thereby making the automatic machine. Soldering is performed.

  As is clear from the above description, the present invention allows soldering of a lead wire to a land by an automatic machine, since the soldering tip of the automatic machine can also apply solder to a portion that contacts the land. After soldering, a portion where no solder is applied does not remain. For this purpose, soldering is performed by an automatic machine in a state where a pre-soldering portion is formed on a part of the land, but it is not necessary to provide a new process for forming the pre-soldering portion.

Diagram showing the shape of the mask and land used when applying cream solder Diagram showing a state in which cream solder is applied and chip-shaped electronic components are soldered Diagram showing soldering process by automatic machine

  With reference to the following, a substrate on which electronic components to be described later are mounted, and 2 is a mask for applying cream solder to conductive lands 3 and 4 provided on the surface of the substrate 1. The mask 2 has openings 21 and 22 corresponding to the lands 3 and 4. A through hole 31 penetrating through the substrate 1 is provided at the center of the land 3, and the land 3 is not circular but has a pair of ends 3a extending on both sides of the through hole 31. ing.

  An opening 21 provided in the mask 2 is for applying cream solder to the end 3 a of the land 3, and an opening 22 is provided for applying cream solder to the entire surface of the land 4.

  Referring to FIG. 2, when cream solder is applied to land 4, chip-shaped electronic component 6 is placed so as to straddle a pair of lands 4 and 4. Electrodes 61, 61 are provided at both ends of the chip-shaped electronic component 6, and both electrodes 61, 61 are in contact with the cream solder applied to the lands 4, respectively. In this state, when the substrate 1 is heated, the cream solder melts to become the solder 5, and the electrodes 61 are soldered to the lands 4 by the melted solder 5.

  On the other hand, the cream solder applied to the end 3a of the land 3 is melted as it is to become the solder 5, which covers the end 3a of the land 3 and pre-solders the end 3a.

  Referring to FIG. 3, a lead wire 8 is inserted into the through hole 31 and the lead wire 8 is soldered to the land 3 by an automatic machine. The iron tip 7 of the automatic machine is formed in a gate shape. A pair of leg portions 72 is provided on both sides of a concave portion 71 formed in the center portion. Then, the thread-shaped solder 70 is fed into the recess 71. The iron tip 7 is heated to a temperature at which the pre-soldered solder 5 and the thread-like solder 70 can be melted, and the iron tip 7 is brought into contact with the land 3 as shown in FIG. Then, the leg portion 72 contacts the pre-soldered solder 5 to melt the solder 5.

  In this state, when the thread-like solder 70 is fed into the recess 71, the thread-like solder 70 melts in the recess 71, and as shown in (b), the pre-soldered solder 5 and the thread-like solder 70 melt. The new solder 5 for soldering the lead wires 8 to the lands 3 is integrated with the solder. Further, as shown in FIG. 3B, the solder 5 for soldering the lead wire 8 to the land 3 extends to both ends 3a and covers the entire land 3.

  The present invention is not limited to the above-described embodiment, and various changes may be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Mask 3 Land 3a End 4 Land 5 Solder 6 Electronic component 7 Iron tip 8 Lead wire

Claims (3)

  A land having a through-hole and a land having no through-hole on the surface of the substrate, cream solder is placed on the land having no through-hole, and heated while the electronic components are placed on the cream solder. After melting the electronic component and soldering the electronic component to the land having no through hole, the lead wire inserted into the through hole is connected to the land having the through hole by using an automatic machine using a thread-like solder. In the method of soldering a substrate to be soldered, in the step of placing cream solder on the land having no through-hole, the cream solder is put on the end of the land having the through-hole, and the step of heating is used to form the creamy solder. The solder was melted to form a pre-soldered part, and when soldering with the above automatic machine, the thread-shaped solder and the solder of this pre-soldered part were mutually fused and integrated. Soldering method of the substrate on which the butterflies.   2. The part where the creamy solder is not piled is left between the creamy solder piled on the end of the land having the through hole and the through hole. Soldering method of substrate.   The iron tip used when soldering with the automatic machine is formed in a gate shape, and is configured to supply the thread-like solder to a concave portion sandwiched between a pair of legs of the gate shape, The above-mentioned lands are extended on both sides of the through hole, and the cream solder is piled on the extended portions, and the leg of the iron tip is brought into contact with the pre-solder portion where the cream solder is melted, and soldering is performed by an automatic machine. The soldering method according to claim 1, wherein the soldering is performed.

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