JP2010199232A - Soldering device and soldering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soldering device for, especially, assuring packed amount of solder into a through-hole and surely securing a lead inserted into the through-hole, relating to a soldering method for reflow soldering a surface mounting component and a lead component together. <P>SOLUTION: A metal mask 81 includes an opening 81b where a shielding body 81a is formed at a position corresponding to a through-hole formed on a printed wiring board. An insert hole forming means 82 forms an insert hole which is the hole for inserting a lead of a component having the lead at one end of the through-hole by soldering a cream solder printed through the opening 81b. A lead inserting means 83 inserts a lead toward the insert hole from other end when the cream solder is printed from the other end of the through-hole. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a soldering apparatus and a soldering method for inserting and soldering electronic component leads into through holes formed in a printed wiring board.

  The components mounted on the printed wiring board include a surface mount component (SMD) mounted by soldering on the surface of the printed wiring board, and a through hole formed on the printed wiring board. There are electronic components (also referred to as through-hole lead components, hereinafter referred to as lead components) that are mounted by inserting and soldering leads. FIG. 8 is a flowchart showing an example of a general process for soldering the SMD and the lead component to the printed wiring board. In general, the soldering of the SMD and the lead component mounted on the printed wiring board is first performed by cream solder printing on the solder surface (step S71), and after mounting the SMD (step S72), the SMD is reflowed. Soldering is performed (step S73). Thereafter, the same processes as steps S71 to S73 are performed on the component surface (steps S74 to S76). After the reflow soldering of the SMD, the lead component is soldered by soldering iron or flow soldering (step S77).

  FIG. 9 is a flowchart showing an example of a general process for soldering the SMD and the lead component together on the printed wiring board. The process until the SMD is soldered to the solder surface is the same as steps S71 to S73 shown in FIG. Thereafter, cream solder printing for SMD and solder solder printing on the through hole and its periphery (hereinafter referred to as a through hole lead portion) are performed on the component surface (step S78). Thereafter, when the SMD and the lead component are mounted on the component surface (step S79), they are soldered by reflow (step S80). Various methods for reflow soldering the SMD and the lead parts together in this way have been proposed.

  Patent Document 1 describes a method of soldering an insertion component such as an IC or a connector mounted on a printed wiring board. The soldering method described in Patent Document 1 includes a surface mount component cut-out pattern for applying cream solder to a surface mount component, and an insert component at the same position as a through hole land portion for component insertion on a printed wiring board. A metal mask having a hollow pattern is used. Through this metal mask, cream solder is applied onto the printed wiring board, and an insertion part is mounted on the through-hole land portion to which the cream solder is applied, and reflow soldering is performed.

  Patent Document 2 describes a soldering method that can reduce the number of soldering steps for a component having a lead to be inserted into a conventional insertion term hole. In the soldering method described in Patent Document 2, a solder paste is printed and applied to the surfaces of electrodes and lands on a printed circuit board. Then, by melting the solder paste at a high temperature in the reflow process, solder parts that have both the one that connects to the electrode on the printed circuit board and the one that is inserted into the hole and soldered (lead) in one step. To do.

  On the other hand, various methods for increasing the amount of solder filled in the through hole into which the lead component is inserted have been proposed. Patent Document 3 describes a soldering method for leaded electronic components in which cream solder is injected into a through hole. In the soldering method described in Patent Document 3, a printing mask is arranged at a predetermined position on a substrate. Cream solder is placed on the upper surface of the printing mask, and cream solder is injected into the through-hole by a plurality of squeegee printing operations.

  Patent Document 4 describes a component mounting structure for a substrate that reliably eliminates the exposure of the copper foil portion, improves the soldering flow by reflow, and improves the soldering quality. In the base component mounting structure described in Patent Document 4, the diameter of the through hole on the upper surface of the substrate (hereinafter referred to as “A surface”) is larger than the diameter of the lower surface of the substrate (hereinafter referred to as “B surface”). Is inclined toward the bottom surface of the substrate. When the solder paste is printed with the A side facing upward, the solder paste flows downward due to the inclination inside the through hole. Further, the solder paste is melted by heating by reflow, and the molten solder paste is poured downward. In this way, the solder paste is filled and printed on the entire inner wall of the through hole.

  Furthermore, Patent Document 5 describes a mounting substrate that prevents the solder from being dropped due to the overfilling of cream solder and the reflow of the melted solder. In the mounting substrate described in Patent Document 5, a shield is provided in a portion corresponding to a through hole of a printing mask used for screen printing. Since cream solder is not supplied to the portion where the shield is provided, a slit-like lead insertion space is formed in the through hole. Even if the lead is inserted into the portion, the cream solder is not pushed out, so that it is possible to prevent the molten solder from dropping during reflow and causing a shortage of solder. Also, this mounting substrate is printed with cream solder (hereinafter referred to as “preliminary solder”) on the back surface (specifically, on the ring-shaped land on the back surface) of the electronic component with the insertion lead. This preliminary solder is melted with the cream solder in the through hole, and the surface tension is relaxed to prevent the solder from falling and causing a shortage of solder.

Japanese Patent Laid-Open No. 5-55734 (paragraph 0004, FIG. 1) JP 2001-217533 A (paragraphs 0010, 0013, FIG. 2) Japanese Patent Laid-Open No. 11-112134 (paragraph 0007, FIG. 1) JP 2000-353867 (paragraphs 0009, 0018 to 0021, 0022, 0024 to 0026, FIG. 2) JP 2002-26502 A (paragraphs 0010, 0023 to 0038, 0040)

  In order to ensure a sufficient solder filling amount in the through hole into which the lead component is inserted, it is necessary to increase the metal mask opening area of the through hole lead portion. However, if the lead interval of the lead parts is narrow, even if you try to increase the metal mask opening area of the through-hole lead part, the necessary metal mask opening area is secured in one place in relation to the adjacent metal mask opening hole. Can not. Accordingly, when the lead interval between the lead components is narrow, the solder filling amount in the through hole is not sufficient, and a solder shortage defect may occur.

  FIGS. 10 and 11 are explanatory views for explaining an example in which the solder filling amount in the through hole is not sufficient when the SMD and the lead component are reflow soldered together. FIG. 10 shows an example in which the solder surface SMD 61 is soldered by reflow soldering on the solder surface side, and then cream solder 521 is printed on the through hole 550 and the pad 60 on the component surface side. In this state, when the lead 71 of the lead component 70 is inserted into the through hole 550 and reflow soldering is performed, a solder shortage defect may occur in the through hole 550 as in the example shown in FIG.

  Although a solution to increase the amount of solder by increasing the thickness of the metal mask can be considered, the thickness of the metal mask is generally set to 150 μm to 200 μm in many cases. Therefore, when a metal mask is formed and used in a thickness exceeding the range, the quality of SMD soldering may be hindered. Therefore, there is a limit in increasing the amount of solder in the through-hole lead portion by increasing the thickness of the metal mask.

  In the soldering method described in Patent Literature 3, cream solder to be injected into the through hole is increased by imprinting with a squeegee a plurality of times. However, the number of times of SMD cream solder printing is generally set to a maximum of 2 times. If SMD cream solder printing is repeated many times, the reflow soldering quality may be impaired. There is a problem that it is difficult to apply.

  Further, when the structure described in Patent Document 4 is applied to a printed wiring board, there is a problem that it is necessary to revise the printed wiring board and it is difficult to process the through hole. In this structure, the solder paste for soldering the lead is printed on the opposite side of the lead insertion direction, and the solder paste is melted and poured into the through hole for soldering. Even in this case, there is a limit in increasing the amount of solder to be inserted from one side, and there is a risk that the amount of solder to be printed around the through hole will be insufficient. The melted solder flows along each of the land and the lead. However, when the amount of solder is insufficient, a gap is formed between the land and the lead due to insufficient solder. In this case, the component surface side mounting becomes unsatisfactory, and there is a risk that the electronic component will wobble.

  Further, when the lead insertion space is formed by the mounting substrate described in Patent Document 5, if the printed solder solder is insufficient from the surface where the electronic component with the insertion lead is provided, the surface opposite to the through hole cannot be filled. There is a case. In this case, even if the preliminary solder is coated on the opposite surface of the through hole, it is difficult to fill the through hole using the preliminary solder.

  Therefore, the present invention is a soldering method in which surface mount components and lead components are reflow soldered together, and in particular, the amount of solder filling into the through holes can be secured and the leads inserted into the through holes can be securely fixed. An object of the present invention is to provide a soldering method that can be performed.

  The soldering apparatus according to the present invention solders a metal mask having an opening in which a shield is formed at a position corresponding to a through-hole formed in a printed wiring board and cream solder printed through the opening. The insertion hole forming means for forming the insertion hole which is a hole for inserting the lead of the lead-attached component at one end of the through hole, and when the cream solder is printed from the other end of the through hole, the insertion hole from the other end And a lead insertion means for inserting the lead toward the head.

  A soldering method according to the present invention includes a cream solder printing step of printing cream solder through an opening of a metal mask in which a shield is formed at a position corresponding to a through hole formed in a printed wiring board, and soldering the cream solder. Thus, when the cream solder is printed from the other end of the through hole, the insertion term forming step for forming the insertion hole which is a hole for inserting the lead of the lead-attached component at one end of the through hole is performed from the other end. And a lead insertion step of inserting a lead toward the insertion hole.

  According to the present invention, in the soldering method in which the surface mount component and the lead component are reflow soldered together, in particular, the amount of solder filling into the through hole can be secured and the lead inserted into the through hole can be securely fixed. can do.

It is explanatory drawing which shows the example in the case of performing reflow soldering on the solder surface side. It is explanatory drawing which shows the example of the state which carried out the reflow soldering of the solder surface side. It is explanatory drawing which shows the example in the case of performing reflow soldering on the component surface side. It is explanatory drawing which shows the example of the state before inserting a lead in a through hole after printing cream solder on the component surface side. It is explanatory drawing which shows the example of the state which reflow soldered SMD and the lead component to the component surface side collectively. It is a flowchart which shows the example of the process of carrying out the reflow soldering of SMD and a lead component collectively. It is a block diagram which shows the minimum structure of the soldering apparatus in this invention. It is a flowchart which shows the example of the general process of soldering SMD and a lead component to a printed wiring board. It is a flowchart which shows the example of the general process of soldering SMD and a lead component collectively to a printed wiring board. An example of a state in which cream solder is printed on through holes and pads on the component side is shown. It is explanatory drawing which shows the example in the case of causing a solder shortage defect in a through hole.

  Hereinafter, embodiments of a soldering apparatus according to the present invention will be described with reference to the drawings.

  FIG. 1 is an explanatory diagram showing an example in which reflow soldering is performed on the solder surface side using the soldering apparatus according to the present invention. The soldering apparatus according to the present invention includes a squeegee 50, a solder surface side metal mask 100 (hereinafter referred to as a metal mask 100), and component mounting means (not shown). The squeegee 50 prints the cream solder 40 placed on the metal mask 100 on the solder surface side 510 of the printed wiring board 500.

  The component mounting means mounts SMD and lead components on the printed wiring board 500. The component mounting means mounts the SMD on the pad on which the cream solder 40 is printed, or inserts the lead component into the through hole 550. The component mounting means is realized by, for example, a mounter that arranges electronic components on the printed wiring board 500. The component mounting means is not limited to the mounter. For example, the SMD or the lead component may be mounted on the printed wiring board by a hand-mounted method.

  The metal mask 100 has a lead part metal mask opening 110 at a position corresponding to the through hole 550 formed in the printed wiring board 500 to be reflow soldered, and an SMD metal mask opening 120 at a position corresponding to the pad 560. Each is formed. In the squeegee 50, the cream solder 40 placed on the metal mask 100 is passed through the lead part metal mask opening 110 to the through hole 550 and its periphery (hereinafter also referred to as a through hole lead part), and also to the SMD. Printing is performed on the pads 560 through the metal mask openings 120.

  Further, a mask opening relief 111 that is slightly smaller than the inner diameter of the through hole 550 is formed in the metal mask opening 110 for the lead component. The mask opening relief 111 is formed such that when the squeegee 50 prints the cream solder 40 in the through hole 550, the cream filling into the through hole 550 is restricted and the hole of the through hole 550 is not completely blocked. That is, when the squeegee 50 prints the cream solder 40 on the solder surface side 510, the cream solder 40 is filled so as not to completely block the hole of the through hole 550 by the lead part metal mask opening 110 and the mask opening relief 111. Is done. A lead part metal mask opening 110a shown in FIG. 1 is an example of an opening when the metal mask 100 is viewed from above.

  FIG. 2 is an explanatory view showing an example of a state where the solder surface side 510 is reflow soldered. In the example shown in FIG. 2, after cream solder printing, the SMD 61 mounted with the pad 560 is soldered by reflow. Further, the cream solder 40 printed on the through-hole lead part is soldered to the inside of the through-hole 550 and the periphery of the through-hole 550 on the solder side 510, and the hole 552 is formed inside the through-hole 550. Show.

  FIG. 3 is an explanatory view showing an example in which reflow soldering is performed on the component surface side using the soldering apparatus according to the present invention. The soldering apparatus according to the present invention is provided with a component surface side metal mask 200 (hereinafter referred to as a metal mask 200) in addition to the squeegee 50, the metal mask 100, and the component mounting means. The squeegee 50 prints the cream solder 40 placed on the metal mask 200 on the component surface side 520 of the printed wiring board 500, similarly to the solder surface side 510.

  The metal mask 200 has a lead part metal mask opening 210 at a position corresponding to the through hole 550 formed in the printed wiring board 500 to be reflow soldered, and an SMD metal mask opening 220 at a position corresponding to the pad 560. Each is formed. In the squeegee 50, the cream solder 40 placed on the metal mask 200 is passed through the lead part metal mask opening 210 to the through hole 550 and its periphery (that is, the through hole lead portion), and through the SMD metal mask opening 220. Printing is performed on each pad 560. The lead part metal mask opening 210a shown in FIG. 3 is an example of an opening when the metal mask 200 is viewed from above.

  FIG. 4 is an explanatory diagram showing an example of the state before the solder 71 of the lead component 70 is inserted into the through hole 550 after the cream solder 521 is printed on the component surface side 520. The lead 71 is inserted into the through-hole 550 on which the cream solder 521 is printed. At this time, the component mounting means places the lead 71 toward the hole 552 formed when the solder surface side 510 is reflow-soldered. insert. Since the periphery of the hole 552 is already soldered, the lead 71 is less likely to be displaced in the left-right direction until the component mounting means inserts the lead 71 and reflows. Therefore, the lead 71 inserted into the through hole 550 is securely fixed by reflow on the component surface side 520.

  FIG. 5 is an explanatory diagram showing an example of a state in which the SMD and the lead component are reflow soldered to the component surface side 520 at once. In the example shown in FIG. 5, it is shown that the SMD 62 mounted with the pad 560 after cream solder printing is soldered by reflow. The cream solder printed on the through hole lead portion is soldered to the inside of the through hole 550 and around the through hole 550 on the component surface side 520, and the lead 71 inserted into the through hole 550 is connected to the component surface side 520. Fixed by reflow soldering.

  In order to form the hole 552 into which the lead 71 is inserted, the dimension of the mask opening relief 111 shown in FIG. 1 is determined in consideration of the inner diameter 551 of the through hole 550 and the diameter of the lead 71 of the lead component 70 shown in FIG. do it. For example, the mask opening relief 111 may be formed smaller than the diameter of the through hole 550 and larger than the diameter of the lead 71 to be inserted. In this case, the cream solder printed by the squeegee 50 can be collectively printed on the through hole 550 and its periphery (that is, the through hole lead portion).

  In this way, the cream solder 40 is filled from the solder surface side 510 to the through hole 550 and the hole of the through hole 550 is not completely blocked by the mask opening relief 111, thereby leading to the through hole 550. 71 can be inserted, and the lead 71 can be securely fixed. In addition, even when the lead interval of the lead component 70 is narrow and a necessary metal mask opening area cannot be ensured, the amount of solder filling the through hole 550 can be ensured, so that the amount of solder in the through hole lead portion is not insufficient. And lead components can be reflow soldered together.

  Next, the operation will be described. FIG. 6 is a flowchart showing an example of a process of reflow soldering the SMD and the lead component together. First, cream solder printing is performed on the pads 560 and the through-hole leads on the solder surface side 510 (step S11). Specifically, as shown in the example of FIG. 1, the metal mask 100 is used for printing on the solder surface side 510 of the printed wiring board 500. When the cream solder 40 is placed on the metal mask 100, the squeegee 50 performs cream solder printing on the pads 560 and the through-hole leads on the solder surface side 510.

  Cream solder 511 is filled not only on the solder surface of the printed wiring board 500 but also inside the through hole in the through hole lead portion, but due to the mask opening relief 111 slightly smaller than the inner diameter 551 of the through hole 550, The cream solder 511 inside the through hole 550 is printed so as not to completely block the hole of the through hole 550.

  When cream solder printing is performed on the solder surface 510, the component mounting means mounts the SMD on the pad 560 on the solder surface 510 on which the cream solder is printed (step S12). The SMD can be mounted either manually or automatically by a mounter. The printed wiring board 500 on which the SMD is mounted is flowed into a reflow furnace, and reflow soldering is performed on the solder surface side 510 (step S13). An example of a state in which the solder surface side 510 is reflow soldered is shown in FIG. The cream solder printed on the through hole lead portion on the solder side 510 in step S12 is soldered inside the through hole 550 by reflow heating. Further, since the amount of cream solder into the through hole 550 is limited by the mask opening relief 11, soldering is performed so as not to block the hole of the through hole 550.

  The printed wiring board 500 to which the SMD 61 is reflow-soldered is turned over, and cream solder printing is performed on the pads 560 and the through-hole lead portions on the component surface side 520 (step S14). Specifically, as shown in the example of FIG. 3, the metal mask 200 is used for printing on the component surface side 520 of the printed wiring board 500. When the cream solder 40 is placed on the metal mask 200, the squeegee 50 performs cream solder printing on the pads 560 and the through-hole lead portions on the component surface side 520. Cream solder 521 is printed not only on the solder surface of the printed wiring board 500 but also inside the through hole in the through hole lead portion. At this time, the cream solder 521 inside the through hole 550 contacts the solder 512 on the inner wall of the through hole 550 soldered in step S13.

  When cream solder printing is performed on the component surface side 520, the component mounting means mounts the SMD 62 on the pad 560 on the component surface side 520 on which the cream solder 40 is printed. Further, the component mounting means inserts the lead 71 of the lead component 70 from the component surface side 520 of the through hole 550 of the printed wiring board 500 (step S15). The mounting of the SMD 62 and the insertion of the lead 71 into the through hole 550 may be performed either manually or automatically by a mounter.

  The printed wiring board 500 on which the SMD 62 and the lead component 70 are mounted is flowed into a reflow furnace, and reflow soldering is performed on the component surface side 520 (step S16). An example of a state in which the component surface side 520 is reflow soldered is shown in FIG. The cream solder printed on the through-hole lead portion on the component surface side 520 in step S14 is melted together with the solder 512 soldered to the inner wall of the through-hole 550 in step S13 by reflow heating. 550 solder inside.

  In the above description, the case where the SMD is mounted only on the pad 560 on the solder surface side 510 or the component surface side 520 has been described. In addition, an electronic component in which some terminals of the SMD are leads (hereinafter, referred to as “leaded SMD”) may be used. In this case, when reflowing the surface opposite to the surface on which the SMD with lead is mounted, a hole is formed inside the through hole into which the lead of the SMD with lead is inserted. When the printed wiring board is turned over and cream solder is printed, the component mounting means inserts the lead into the through hole in which the hole is formed and mounts the SMD with the lead on the pad. The mounted SMD with lead is reflow soldered in the same manner as described above.

  According to the present invention, cream solder is printed through the lead part metal mask opening 110 of the metal mask 500 in which the mask opening relief 111 is formed at a position corresponding to the through hole 550 formed in the printed wiring board 500. And the hole 552 for inserting the lead 71 of the lead component 70 is formed in the solder surface side 510 of the through hole 550 by reflow soldering the printed cream solder. Then, when cream solder is printed from the component surface side 520 of the through hole 550, the lead 71 is inserted from the component surface side 520 of the through hole 550 toward the hole 552. Therefore, it is possible to secure the solder filling amount in the through hole 550 and to securely fix the lead 71 inserted into the through hole 550.

  That is, when the SMD and the lead component are reflow soldered together, even if the lead interval between the lead components is narrow, a sufficient amount of solder can be secured in the through-hole lead portion. Also, the SMD soldering method procedure for the SMD mounted on the printed circuit board, the number of times of cream solder printing, the change of the thickness of the metal mask, the revision of the printed circuit board, and the SMD and the lead parts can be performed in a batch without soldering. Reflow soldering can be done without any shortage.

  FIG. 7 is a block diagram showing the minimum configuration of the soldering apparatus according to the present invention. In the soldering apparatus according to the present invention, the shield 81a (for example, the mask opening relief 111) is provided at a position corresponding to a through hole (for example, the through hole 550) formed in the printed circuit board (for example, the printed circuit board 500). Solder the formed metal mask 81 (for example, metal mask 100) having the opening 81b (for example, metal mask opening 110 for lead parts) and cream solder printed through the opening 81b (for example, reflow soldering). By doing so, an insertion hole (for example, hole 552), which is a hole for inserting a lead of a component with lead (for example, lead component 70), into one end of the through hole (for example, solder surface side 510 of through hole 550). Insert hole forming means 82 (for example, squeegee 50) to be formed and the other end (for example, a squeegee 50) of the through hole. When printing the cream solder from Horu component side 520 of the 550), the lead insertion means 83 for inserting the lead toward the insertion hole from the other end (e.g., comprising the component mounting means).

  With such a configuration, especially in the soldering method of reflow soldering surface-mounted components and lead components together, it is possible to secure the amount of solder filling into the through holes and to securely fix the leads inserted into the through holes. can do.

  In other words, by filling the through-hole with cream solder from one end of the through-hole and printing the cream solder so as not to completely block the through-hole with the shield, reflow soldering is performed. The lead can be inserted into the lead and the lead can be securely fixed. Further, even when the lead interval of the leaded parts is narrow and the required metal mask opening area cannot be secured, the amount of solder filling into the through hole can be secured, so that the SMD and the solder amount of the through hole lead portion can be secured. Reflow soldering to lead parts can be performed at once.

  The shield 81a of the metal mask 81 may be formed smaller than the diameter of the through hole and larger than the diameter of the lead to be inserted. In this case, when the insertion hole forming means 82 forms the insertion hole, the cream solder to be printed in the through hole can be collectively printed on the through hole lead portion.

  Further, when the lead insertion means 83 is a component (for example, SMD with lead) on which the leaded component is also mounted on the printed wiring board, the lead of the component is inserted into the insertion hole, In addition, the component may be mounted.

  The present invention is suitably applied to a soldering apparatus that inserts and solders electronic component leads into through holes formed in a printed wiring board.

40 Cream solder 50 Squeegee 61,62 SMD
70 Lead component 71 Lead 100, 200 Metal mask 110, 110a, 210, 210a Metal mask opening for lead component 120, 220 Metal mask opening for SMD 500 Printed wiring board 511, 521 Cream solder 512 Reflow soldered by reflow soldering Solder 522 Solder reflow soldered by solder surface reflow and component surface reflow 532 Solder reflow soldered by component surface reflow 550 Through hole 552 Hole 560 Pad

Claims (6)

A metal mask having an opening in which a shield is formed at a position corresponding to a through-hole formed in the printed wiring board;
An insertion hole forming means for forming an insertion hole which is a hole for inserting a lead of a component with a lead into one end of the through hole by soldering cream solder printed through the opening;
A soldering apparatus comprising: lead insertion means for inserting the lead from the other end toward the insertion hole when cream solder is printed from the other end of the through hole. The soldering apparatus according to claim 1, wherein the shield of the metal mask is formed smaller than the diameter of the through hole and larger than the diameter of the lead to be inserted. The lead insertion means inserts the lead of the component into the insertion hole and mounts the component on the printed wiring board when the leaded component is a component that is also mounted on the printed wiring board. Or the soldering apparatus of Claim 2. A cream solder printing step of printing cream solder through an opening of a metal mask in which a shield is formed at a position corresponding to a through hole formed in a printed wiring board;
By inserting the cream solder, an insertion term forming step of forming an insertion hole which is a hole for inserting a lead of a lead-attached component at one end of the through hole;
And a lead insertion step of inserting the lead from the other end toward the insertion hole when cream solder is printed from the other end of the through hole. 5. The soldering method according to claim 4, wherein in the cream solder printing step, the cream solder is printed through an opening of a metal mask formed so that the shield is smaller than the diameter of the through hole and larger than the diameter of the lead to be inserted. 5. In the lead insertion step, when the leaded component is a component that is also mounted on the printed wiring board, the lead of the component is inserted into the insertion hole and the component is also mounted on the printed wiring board. Or the soldering method of Claim 5.

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