JP2009195938A - Soldering gun and method for manufacturing electronic device by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soldering gun capable of preventing scattering of flux and executing soldering with high quality. <P>SOLUTION: The soldering gun 1 is constituted such that a cylindrical through-hole is provided on the center axis of the soldering gun 1, a tip of the soldering gun 1 is formed in a cone or pyramid shape, a diameter (d) of a through-hole opening 2 on the tip is 0.5-3 mm and the diameter of a plane including the opening 2 is 2-6 mm, and the material is ceramic, stainless steel, titanium or chromium which is hardly wetted for the solder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a solder iron for melting and soldering thread solder and a method for manufacturing an electronic apparatus using the solder iron.

  As a hook for soldering a land of a wiring board and terminals such as a metal pin and a wire, a hook having a hook shape or a cap shape is known (Patent Document 1). With the pin protruding from the land surrounded by the opening of the tip of the hook, thread solder is supplied into the cap of the hook, and the hook is heated to melt the solder and solder it to the pin, as well as solder to unnecessary parts. It is intended to prevent adhesion and flux scattering. In addition, the wettability with respect to the solder is enhanced by solder plating or the like on the inner surface of the cap that contacts the molten solder.

When using the soldering iron described in Patent Document 1, the inside of the cap is likely to be clogged by the solder adhering to the inner surface of the cap-shaped space, and the solder does not solidify from the air holes formed in the side surface of the soldering iron to prevent this. It is necessary to blow air onto the cap and blow off the solder adhering to the side wall of the cap. Therefore, the soldering apparatus becomes complicated and there are many problems in practical use.
JP-A-11-245029

  A first object of the present invention is to provide a soldering iron that prevents flux from scattering and is less prone to clogging. A second problem is to provide a high-quality electronic device.

In order to solve this problem, in the present invention, by adopting a cylindrical solder rod having the following shape, it was possible to prevent the flux from being scattered and to realize a solder rod that is not easily clogged. That is,
1) It has a cylindrical through hole in the central axis of the soldering iron,
2) The tip of the soldering iron forms a truncated cone or a truncated pyramid, and the diameter (d) of the through-hole opening at the tip is 0.5 to 3 mm.
3) The diameter (D) of the through hole at the rear end of the soldering iron is the same as the diameter (d) of the opening at the tip, or is not less than the diameter (d) of the opening and not more than 9 mm.
4) The solder iron is made of ceramic, stainless steel, titanium or chromium which is difficult to wet with solder.
By using the cylindrical soldering iron characterized by this, the problem of the present invention can be solved.

  According to this soldering iron, there are through-holes in the axial direction of the soldering iron, and both ends of the soldering iron are open, so this soldering iron stands on the land and cut to the length necessary for one soldering. If the threaded solder is inserted from the rear end of the heel, it will fall to the tip and contact the land or pin. Then, the other terminal such as a pin or a wire is joined with a certain amount of solder by melting the solder at the tip of the flange. Since the soldering portion is surrounded by the through hole of the soldering iron, the molten solder or flux does not scatter around, and the molten solder can wrap around evenly. In addition, since the tip of the soldering iron is made of a material (ceramic, stainless steel, titanium, or chrome) that is difficult to get wet with the solder, solder hardly adheres to the inner surface of the through hole, and the through hole is clogged with solder. Can be suppressed. As a result, the quantitativeness of the supplied solder is maintained and the appearance of the pin after joining is finished cleanly.

  In addition, when connecting an electronic component such as a choke coil in which a heat-meltable coated magnet wire (for example, polyurethane-coated copper wire) is wound around a metal pin to the substrate, the wire, the metal pin, and the land The three parties can be soldered simultaneously. This is because the flux eluted from the solder stays in the cylinder without being diffused, purifies the metal surface and makes it easy to get wet with the solder. Therefore, there is no need to solder the wire and the metal pin in advance, which is excellent in that the process can be shortened.

  In this specification, a land means a terminal on an electronic device in a broad sense including a pad having no pin insertion hole.

  As a heating means for melting the solder, a general-purpose heating means can be used as appropriate. As a preferred heating means, a sheathed heater wound in a coil shape on the outer peripheral surface of the soldering iron can be exemplified.

  The soldering iron is heated by the heating means and reaches 250 to 600 ° C. at the tip (opening). A preferable temperature range at the tip (opening) can be 300 to 400 ° C. The melting point of normally used eutectic solder is about 183 ° C, whereas the melting point of Pb-free solder is about 220 ° C, and there is a temperature difference of about 40 ° C. The attaching time (heating time) takes a long time. Therefore, the melting time is short if the temperature near the tip (opening) where the solder piece melts is high, and the melting time is long if the temperature is low. Therefore, it is desirable that the temperature in the vicinity of the tip (opening), which is a solder melting portion, is usually in the range of 300 to 400 ° C. In consideration of solder melting operability, the temperature is most preferably in the range of about 320 to 370 ° C.

Therefore, an appropriate method for manufacturing an electronic device using this soldering iron includes the following steps:
1) Install a heating means for melting the solder at the tip, and heat the tip to a temperature of 250 to 600 ° C.
2) Insert the opening at the tip into the terminal copper wire of the electronic component and bring it into contact with the substrate.
3) Cutting the thread solder into a length necessary for one soldering, and dropping the obtained solder piece from the through hole at the rear end,
4) The falling solder piece is melted in the cylinder at the tip, and during the melting, the cylindrical solder iron is moved relative to the terminal copper wire.
Thus, soldering is performed on the terminal copper wire of the electronic component.

  As for the inner diameter of the through hole of the soldering iron, the diameter (d) of the through hole opening at the front end is 0.5 to 3 mm, and the diameter (D) of the through hole at the rear end is the diameter of the opening at the front end. It is the same as (d), or is not less than the diameter (d) of the opening and not more than 9 mm. A preferable inner diameter is 1.0 to 2.0 mm.

  In addition, when the diameter (d) of the opening part of a front-end | tip part and the diameter (D) of the through-hole of a rear-end part differ, the length (L) of the through-hole of the internal diameter (d) installed in the front-end | tip part is 0. It is desirable that it is 5-15 mm. Alternatively, it is desirable that there is almost no length (L) of the through hole at the tip, and the tip is a tapered hole.

  Of course, the inner diameter of the through hole is larger than the outer diameter of the solder piece, and when the pin is inserted, it is larger than the outer diameter of the pin.

  The tip of the soldering iron has a truncated cone or truncated pyramid shape and protrudes below the heating means (heating block).

In addition, an apparatus suitable for this manufacturing method is:
A solder holding hole that is formed of a cutting blade and a receiving blade and can accept thread solder of a predetermined length is formed in at least one of them, and is inserted into the solder holding hole by being relatively displaced while rubbing against each other. A cutter unit for cutting thread solder;
At least the tip is formed of a material that is difficult to wet with solder, has a through hole with an inner diameter through which thread solder can pass,
Heating means for melting solder at the tip,
A shutter for opening and closing the rear end of the soldering iron is provided.

  In one specific configuration of the cutter unit, the cutting blade can advance and retreat in one direction according to the output of the drive source, and the solder holding hole is formed to penetrate in a direction perpendicular to the advancing and retreating direction of the cutting blade. The In this case, the receiving blade has a recess that guides the cutting blade in the advancing and retreating direction, and a solder supply hole that is aligned with the through hole when the cutting blade is retracted is formed on one side, and the cutting blade is formed on the same side or the opposite side. A solder discharge hole that is aligned with the through hole is formed during the forward movement. And the through-hole of the said soldering iron is put so that a radial direction position may correspond with the said solder discharge hole.

  According to this structure, when the cutting blade is advanced with respect to the receiving blade in a state where the thread solder is supplied from the supply hole to the holding hole, the shearing force acts on the fitting portion of both the blades and the thread solder is cut. The obtained solder piece comes out of the discharge hole, enters the cylinder, falls by its own weight, and is grounded to the land where the tip of the through hole of the soldering iron is in contact. And it heat-melts and joining is performed as above-mentioned. The solder used for one-time soldering is a fixed-length solder piece determined by the length supplied to the holding hole. The length of the thread solder supplied to the holding hole can be controlled by the number of rotations of the solder feed roller.

  Preferably, the solder supply hole side has an introduction hole for receiving a gas or a plunger. This is because even if burrs or bends are generated in the solder piece obtained by cutting, the solder piece can be discharged by blowing compressed gas from the introduction hole into the holding hole or inserting a plunger. The inner diameters of the solder holding hole and the cylinder are preferably smaller than the axial length of the solder holding hole. As a result, the solder piece can be sent to the tip of the solder iron with a small amount of resistance in the axial state.

  In another specific configuration of the cutter unit, the cutting blade can advance and retreat in one direction according to the output of the drive source, and the receiving blade has a flat surface that guides the cutting blade in the advance and retreat direction. In this case, the solder holding hole penetrates in the direction perpendicular to the advancing and retreating direction of the cutting blade and is formed in the receiving blade. And the through-hole of the said soldering iron is set | placed so that a radial direction position may correspond with the said solder holding hole.

  According to this structure, when the cutting blade is advanced with respect to the receiving blade in a state in which the thread solder is supplied to the holding hole, the shearing force acts on the fitting portion of both the blades, and the thread solder is cut. The obtained solder piece comes out of the holding hole, enters the through hole of the solder rod, falls by its own weight, and is grounded to the land where the tip of the solder rod contacts. And it heat-melts and joining is performed as above-mentioned. The solder used for one-time soldering is a fixed-length solder piece determined by the length supplied to the holding hole in the same manner as described above.

In one specific configuration of the shutter that opens and closes the rear end portion of the soldering iron, the shutter is installed between the solder discharge hole and the soldering iron, and can advance and retreat in one direction according to the output of the driving source. . The shutter has an opening having a diameter that overlaps with the through hole portion of the soldering iron. This opening has a solder holding hole and a discharge hole that coincide with each other, and when the thread solder is cut and falls by its own weight, it exists on the through hole of the solder rod and can guide the falling thread solder to the through hole. It is like that. In other cases, the through hole is shielded.

  According to the soldering iron of the present invention, it has a tip having a through hole with a fine inner diameter of 0.5 to 3 mm, and there is no scattering of solder or flux when soldering a precision electronic device, and the quality is good. Things are obtained. Furthermore, since it has a cylindrical tip, the solder solder grounded to the land as described above is heated (radiant heat, conduction heat, convection heat) from the peripheral wall of the through hole, so that more accurate soldering is possible. became. Further, the material of the soldering iron of the present invention is different from conventional soldering iron materials (copper and iron) and is made of a material having no solder wettability such as ceramic, stainless steel, titanium or chromium. Therefore, when the soldering iron of the present invention is used, unlike conventional ones, copper and iron do not melt into the solder, so that high quality soldering can be performed.

Embodiment 1
An embodiment of a soldering iron of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the shape of a through hole of a soldering iron having a straight through hole in which the diameter (d) of the opening at the front end and the diameter (D) of the through hole at the rear end are the same. Shows soldering iron.

  FIG. 2 is a cross-sectional view of the soldering iron when the diameter (d) of the opening at the front end and the diameter (D) of the through hole at the rear end are different. This soldering iron indicates that a through hole having an inner diameter (d) is provided at the tip portion by the length (L).

  FIG. 3 is a cross-sectional view of a soldering iron whose tip is a tapered hole when the length (L) of the through hole at the tip of the soldering iron is 0.5 mm or less.

  In FIG. 1, the through hole 2 of the soldering iron 1 has substantially the same inner diameter as the holding hole and penetrates vertically. The tip of the solder iron protrudes below the heating block 3, and the tip outer diameter is tapered in order to avoid interference with peripheral components. In addition, the shape of the entire tip of the soldering iron contacting the land of the electronic device is a truncated cone shape or a truncated pyramid shape.

  The material of the soldering iron may be any material as long as it can withstand a temperature of about 600 ° C. and has a property that does not easily wet the solder, and may be composed of a single material or a combination of a plurality of members. . In the case of a single material, ceramic or a non-solder wettable metal such as stainless steel, titanium or chromium is desirable. In the case of a ceramic, a high thermal conductive ceramic such as aluminum nitride or silicon carbide is particularly desirable.

  The diameter (d) of the through hole 2 of the soldering iron 1 may be appropriately determined according to the amount of solder necessary for one soldering, but is larger than the diameter of the supplied solder piece and larger than the diameter of the pin to be soldered. Big is essential. For example, when the outer diameter of the pin is 0.6 mm, the diameter of the thread solder W is 0.8 mm, the inner diameter (d) of the through hole 2 is 1.2 mm, and the length of the cut piece (solder piece) of the thread solder W is By setting the thickness to 1.2 mm, the solder piece comes into contact with the pin or the side wall of the through hole in the through hole 2 and stands up, and the entire solder piece is quickly heated. Therefore, even when the thread solder W is lead-free solder, if the lower end temperature of the solder iron tip is 350 ° C., soldering can be performed satisfactorily.

  As the heating means 3, a general-purpose heating means can be applied, and the heating means 3 can be heated by a separate heater from the soldering iron 1. Specifically, for example, a sheathed heater can be wound. In any case, it is desirable to apply an efficient heating means that quickly heats up the soldering iron 1 and rises quickly. Furthermore, the preheating of the lands to be soldered may be performed by radiant heat from the soldering iron, or may be performed by contacting the soldering iron directly with the lands and pins and using conduction heat.

  FIG. 2 shows the soldering iron 1 when the diameter (d) of the opening 2 at the front end and the diameter (D) of the through hole 4 at the rear end are different. The diameter (D) of the through hole 4 at the rear end of the soldering iron has such a diameter that the solder piece easily falls and the solder piece is caught and melted in the middle of dropping or the flux in the solder piece does not evaporate. It is desirable. Specifically, although it is related to the diameter (d) of the opening 2 at the tip, the diameter (D) is in the range of 1 to 5 times the diameter (d). Further, a through hole having a length (L) is provided at the tip portion, and a taper in the solder rod is constructed so that the solder piece can fall and melt in the through hole.

  The length (L) of the through hole of the inner diameter (d) is appropriately selected depending on the diameter and length of the solder piece, or the size of the terminal and land to be soldered, but is in the range of 0.5 to 15 mm. Is desirable. More preferably, the range of 1-10 mm can be mentioned.

  The material of the soldering iron, the heating means, etc. are the same as in FIG.

  FIG. 3 shows a solder iron in which the length (L) of the through hole at the tip of the solder iron is 0.5 mm or less or has almost no length (L), and the inside of the through hole at the tip is tapered. A soldering iron that is a hole is shown. As in the case of FIG. 2, the taper hole is constructed so that the falling solder piece is not caught and melted in the middle, but is grounded to the land and melted there. .

The relationship between the diameters (D) and (d), the material of the soldering iron, the heating means, and the like are the same as those in FIGS.
Embodiment 2
An embodiment of a manufacturing method using the soldering iron of the present invention is shown as a cross-sectional view of a main part in FIGS. That is, the procedure for soldering using a soldering apparatus is as follows.

  Metal pins are inserted into the lands of the wiring board, and this wiring board 5 is placed on a jig. Then, the jig is moved together with the wiring board 5 so that the land to be soldered is positioned directly below the solder iron (opening 2 at the tip). Lower the solder iron to the point where the lower end of the soldering iron is located in the immediate vicinity of the land or the point where it contacts the land. As shown in FIG. 4, the cutting blade 8 is moved backward until the holding hole 9 coincides with the supply hole 10. The lands and pins are preheated by the radiant heat of the soldering iron. The feed roller 11 is rotated to draw the thread solder W from the solder reel and pass through the supply hole 10. When the thread solder W enters the holding hole 9 and is fed a predetermined length, the feed roller 4 is stopped. The feed amount of the thread solder W is controlled by the rotational speed of the feed roller 4. In this state, the cylinder 12 is driven to advance the cutting blade 8 forward.

  When the cutting blade 8 is moved forward, as shown in FIG. 5, a shearing force is applied between the cutting blade 8 and the receiving blade 7 so that the thread solder W is cut into a predetermined length to become a solder piece and the holding hole 9. At the same time, it moves onto the discharge hole 13. Here, the solder piece is pushed out from the holding hole 9 by the pusher 15 connected to the introduction hole 14. The solder piece passes through the opening of the shutter from the discharge hole 13 and falls into the through hole 4 of the soldering iron, and is grounded to the land. The solder pieces that have reached the land are melted by the heat of the inner wall of the tip of the soldering iron to join the land and the pin. At that time, since the molten solder is surrounded by the through hole of the solder iron, the solder and flux are not scattered around. In addition, since the solder iron is formed of a material that is difficult to wet with the solder, the entire amount of the solder piece is consumed for joining the metal pin and the land, and the appearance after the joining is finished cleanly.

Further, while the falling solder piece is melted in the cylinder at the tip portion, the molten solder can be sufficiently fitted to the land and the pin by relatively moving the cylindrical solder rod around the pin. That is, as shown in FIG. 6, for example, the object can be achieved by causing the solder iron to move eccentrically around the pin. For example, in the embodiment shown in the cross-sectional view of the main part in FIG. 6, first, as shown in FIG. 6A, the solder piece is dropped into the through hole of the soldering iron 1 and melted. Then, as shown in FIGS. 6B and 6C, the soldering iron 1 is moved in one direction (left direction in the drawing) and then moved in the opposite direction (same right direction). Thereby, the molten solder spreads to both ends of the land. More preferably, it is also moved in the front-rear direction. When the soldering iron 1 is retracted upward, the solder spreads over the entire land as shown in FIG. In any case, the soldering iron 1 may be moved relative to the land. Further, as shown in FIG. 6E, the soldering iron 1 may be revolved or eccentrically moved around the pin 18 by a turning mechanism (not shown). As a result, high quality soldering can be achieved. The shutter is composed of a cylinder 16 fixed to the receiving blade 7, a rod 17, and a shutter plate 6. As the rod 17 reciprocates, the shutter is soldered to the discharge hole 13. The rear end of the through hole 4 is opened and closed by moving back and forth in the horizontal direction between the through hole 4 of the bag.

  When the holding hole 9 and the discharge hole 13 are in the same phase, the opening of the shutter plate moves in conjunction so that the opening also matches. Therefore, only when the solder piece is discharged from the discharge hole 13, the shutter is opened and the falling solder piece can enter the through hole 4 of the solder rod. As a result, the shutter is closed except when necessary. For this reason, the flux volatilized from the molten solder purifies the surfaces of the lands and pins without adhering to the discharge holes 13 and the holding holes 9. Therefore, the land and the pin are joined well. Furthermore, radiant heat from the soldering iron can be shielded. Further, it is possible to shield the adhesion of dirt due to the scattering of the flux generated at the time of melting the solder and the generation of smoke. As a result, the durability of the device parts other than the soldering iron can be further improved.

The following examples are intended to assist the understanding of the present invention and are not limited thereto.
Example 1:
A soldering iron formed of an aluminum nitride sintered body in the shape shown in FIG. 2 was used. A soldering iron with a tip diameter (d) of 1.0 mm, (L) of 5 mm, and a rear end diameter (D) of 2.5 mm was prepared. A lead-free solder having a diameter of 0.8 mm and a solder length of 1.2 mm was prepared.

  A soldering target component having a land diameter of 1.5 mm and an electronic component terminal copper wire diameter of 0.6 mm was prepared and soldered. A solder piece was supplied into the through hole of the soldering iron, and the lower end temperature of the soldering iron tip was maintained at 350 ° C. When the solder melted, an eccentric movement of the soldering iron was performed around the pin. When soldering was performed in this manner, all of the solder pieces adhered to the pins and lands. This was repeated about 30 times, but solder did not adhere to the inner surface of the tip of the solder iron through hole, and no solder clogging occurred.

In contrast to the copper rod-shaped solder rod having solder wettability, the aluminum nitride material of the present invention has no wettability with respect to the solder, and thus the heat conduction to the solder was considered to be poor. Because of the cylindrical shape, it could be melted without much inconsistency by heating from the cylindrical peripheral side wall (radiant heat, convection heat, convection heat). Further, in contrast to the case of the conventional copper soldering iron, in the case of the present invention, it is possible to avoid the melting of copper into the molten solder, so that high quality soldering can be performed.
Example 2:
A soldering iron having the same shape as in Example 1 but made of silicon carbide was prepared and prepared. The other conditions were the same as in Example 1 and soldering was performed. As a result, the same result as in Example 1 was obtained.
Example 3:
A shape having the shape shown in FIG. 1 and made of an aluminum nitride sintered body and having an inner diameter of a through hole of a soldering iron of 2.5 mm was prepared. Further, lead-free solder having a diameter of 1.2 mm and a solder length of 6 mm was prepared.

  When a solder piece was supplied to the rear end portion of the through hole of the solder iron of the present invention and soldering was performed while maintaining the lower end temperature of the tip portion of the solder iron at 350 ° C., all of the solder piece adhered to the pins and lands. . This was repeated several tens of times, but solder did not adhere to the inner surface of the tip of the soldering iron, and no solder clogging occurred.

  For comparison, a copper tube having the same shape and size as the soldering iron of the present invention was produced and soldered in the same manner. As a result, most of the solder pieces adhered to the inner surface of the tube. As a result, the solder was not sufficiently supplied to the lands and the pins, and the pins and the lands were not joined. In addition, solder clogging occurred in the third soldering.

A soldering iron having a straight through hole in which the diameter (d) of the opening at the front end and the diameter (D) of the through hole at the rear end are the same is shown.

It is sectional drawing of a soldering iron in case the diameter (d) of the opening part of a front-end | tip part differs from the diameter (D) of the through-hole of a rear-end part. It is sectional drawing of the soldering iron whose front-end | tip part is a taper hole. It is principal part sectional drawing of the soldering apparatus which showed the state before cut | disconnecting a fixed amount of solder pieces. It is principal part sectional drawing of the soldering apparatus which showed the state after cut | disconnecting a fixed amount of solder pieces. FIG. 3 is a cross-sectional view of a main part of a soldering apparatus sequentially showing a state of a process in which a cylindrical solder iron is relatively moved around a terminal copper wire (pin) to sufficiently wind molten solder around the pin.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solder iron 2 Opening part of solder iron tip 3 Solder iron heating block 4 Opening part 5 of solder iron rear edge Electronic circuit board (land)
6 Shutter plate 7 Receiving blade 8 of solder cutting device Cutting blade 8 of solder cutting device
9 Solder holding hole 10 Solder feeding hole 11 Roller 12 Cylinder 12
13 Solder discharge hole 14 Introduction hole 15 Pusher 16 Cylinder 17 Rod 18 Electronic component terminal copper wire (pin)

Claims (8)

A cylindrical soldering iron having the following shape,
Has a cylindrical through hole in the center axis of the soldering iron,
The tip of the soldering iron has a truncated cone shape or a truncated pyramid shape, and the diameter (d) of the through hole opening at the tip is 0.5 to 3 mm,
The diameter (D) of the through hole at the rear end of the soldering iron is the same as the diameter (d) of the opening at the tip, or is not less than the diameter (d) of the opening and not more than 9 mm.
The solder iron is made of ceramic, stainless steel, titanium or chrome which is hard to get wet with the solder.
A cylindrical soldering iron characterized by that.   When the diameter (d) of the opening at the front end and the diameter (D) of the through hole at the rear end are different, the length (L) of the through hole at the front end is 0.5 to 15 mm. The cylindrical soldering iron according to claim 1.   The cylindrical soldering iron according to claim 1, wherein the diameter (d) of the opening at the front end is different from the diameter (D) of the through hole at the rear end, and the front end is a tapered hole.   The cylindrical soldering iron according to any one of claims 1 to 3, wherein the soldering iron is formed of ceramic.   The cylindrical soldering iron according to any one of claims 1 to 4, wherein the ceramic is aluminum nitride or silicon carbide. A heating means for melting solder at the tip portion is installed in the cylindrical soldering iron according to claim 1 and heated so that the temperature of the tip portion becomes 250 to 600 ° C.
The opening of the tip is inserted into the terminal copper wire of the electronic component and brought into contact with the substrate.
Cut the thread solder into a length required for one soldering, and drop the obtained solder piece through the through hole at the rear end,
A method for manufacturing a soldered electronic device, wherein a falling solder piece is melted in a cylinder at the tip, and a cylindrical solder rod is moved relative to the terminal copper wire during the melting.   The manufacturing method of Claim 6 whose temperature of a front-end | tip part is 300-400 degreeC. The manufacturing method according to claim 6 or 7, wherein the relative motion is an eccentric motion.

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