WO1998030352A1

WO1998030352A1 - Non-contact type soldering iron capable of intermittent soldering

Info

Publication number: WO1998030352A1
Application number: PCT/JP1998/000021
Authority: WO
Inventors: Akio Mitumoto; Kensei Matubara
Original assignee: Kabushikigaisha Taiseikaken
Priority date: 1997-01-07
Filing date: 1998-01-07
Publication date: 1998-07-16
Also published as: JP2000000657A; WO1998030351A1

Abstract

When soldering is carried out by using a soldering iron and by blowing a high temperature gas stream to a to-be-soldered portion of a work, a main heating gas stream having a high temperature sufficient to melt and soften the solder is jetted from the distal end of the soldering iron, and a pre-heating gas stream is generated and jetted from a part of the main heating gas stream by utilizing the back pressure resulting from the temperature rise and expansion of the main heating gas stream in such a manner as to encompass the main heating gas stream. After the pre-heating gas stream is blown to the to-be-soldered portion of the work for pre-heating, the main heating gas stream is blown to the to-be-soldered portion of the work so pre-heated, and soldering is carried out in the atmosphere in which the main heating gas is encompassed by the pre-heating gas stream.

Description

Akitoda

Non-contact soldering iron capable of intermittent soldering

Technical field

The present invention relates to a soldering iron capable of intermittently and non-contactly soldering electronic components, for example.

Background art

For example, when assembling electronic devices, it is often the case that various electronic components and wiring are soldered to an electronic board using a soldering iron.

In this type of soldering iron, a method is widely used in which a tip chip heated by a heater or the like is brought into contact with a land of an electronic substrate to melt the solder, and the tip chip is separated to solidify the solder.

On the other hand, as shown in FIG. 10, an air passage is formed in the soldering iron 100, a heating nozzle 101 is built in, and a nozzle 102 made of stainless steel is provided at the tip. Non-contact soldering irons, which are soldered by blowing high-temperature air, have also been proposed.

However, in the conventional contact-type soldering method, since the tip is brought into contact with the soldering part, thermal stress is applied to the tip by a heat cycle, and diffusion of tin and erosion due to flux occur. The life of the chip was short and it was necessary to replace it about 40,000 to 50,000 times in order to secure soldering accuracy. Also, since the advanced chip comes into direct contact with the electronic substrate and electronic components, leakage current, noise, harmonics, static electricity, etc. are transmitted from the advanced chip to the electronic substrate and electronic components, and there is a concern that the electrical characteristics of the product may be degraded. I was

On the other hand, with the conventional non-contact soldering iron, although the above-mentioned problems do not occur, after the high-temperature air hits the workpiece, it scatters around and the heat is needed to the spot where it is needed. It cannot be concentrated, it takes 4 to 5 seconds for soldering, and it is not practical. It is used for removing (reworking) soldered electronic components. On the other hand, in the soldering method disclosed in Japanese Patent Publication No. 7-83390, a soldering iron is used, and a high-temperature gas flow is blown onto a soldering portion of a work to solder a workpiece. From the main heating gas flow high enough to melt and soften the solder, and a preheating gas flow at a temperature lower than the main heating gas flow and sufficient to preheat the solder. The main heating gas flow is blown to the pre-heated soldering portion while the preheating gas flow is blown to the soldering portion of the work, and the main heating gas flow is blown to the soldering portion of the preheated work. Soldering is performed in an enclosed atmosphere. However, in such a method, there is no problem when the gas flow is continuously ejected. However, when the gas flow is intermittently performed, it is necessary to raise the temperature of the heater to a sufficiently high temperature before flowing the gas flow. It is not practical to generate and eject gas streams.

Accordingly, an object of the present invention is to provide a soldering iron that can quickly generate a high-temperature gas flow in response to an intermittent soldering operation in a non-angled ί soldering iron.

Disclosure of the invention

The soldering iron according to the present invention includes a first chamber for generating a main heating gas flow having a first nozzle at a tip thereof, and a second nozzle which is opened to cover the outside of the first nozzle. A nozzle means provided at the tip, surrounding at least the first chamber, and including at least a second chamber for generating a preheating gas flow; and an inner wall in the first chamber near the central first nozzle. A first core heating means having a heat source for heating an inert gas ejected from a nozzle port through the clearance, and forming at least a distal end of the first chamber; Heating means including at least a second heating means surrounding the heat source of the first core heating means, storing heat, and passing between the first chamber and the second chamber and heating an inert gas. And the above An inert gas supply means for communicating with the first chamber, supplying an inert gas, and branching and supplying the inert gas to be supplied to the first chamber to the second chamber; Inert gas supplied to 1 chamber While the gas passes through the clearance, the temperature rises to a predetermined heating temperature, and the inert gas that rises in temperature and expands in the first chamber is branched and lined into the second chamber by its back pressure. It is characterized by the following.

The gas stream is preferably a high concentration of inert gas. This is because an inert gas such as nitrogen gas is preferable in consideration of the effect of O ₂ in air on soldering quality. The first core heating means only needs to generate heat, such as a nichrome wire heater, a ceramic heater, a high frequency heater, a medium frequency heater, a low frequency heater, an infrared heater, a plasma heater, an ultrasonic heater, An elema heating element or the like can be used. However, in order to achieve the effects of the present invention, the first core heating means has an inner wall and a clearance inside the first chamber, and has a rod-like shape inserted therein. heating evening, lock de-shaped heating evening force desirable especially A ^ ₂ 0 made _3.

One of the features of the present invention is to arrange the outer nozzle around the inner nozzle, form the outer gas flow by utilizing the temperature rise expansion of the inner gas flow, and preheat with the outer gas flow, Surrounded by the outside gas flow. The point is that soldering is performed by the inside gas flow in the surrounding air. As a result, the heat of the gas flow inside does not scatter to the surroundings, soldering can be performed in a short time in a non-contact manner, and the effects of leakage current, noise, and harmonics on products can be eliminated. In addition, since the temperature of the inert gas is raised within a predetermined clearance, the core heating means quickly raises the inert gas to a desired temperature without having to set the temperature to a high temperature such as when merely flowing the inert gas. The soldering work can be quickly performed not only in the case of continuous soldering but also in the case of intermittent soldering. However, with regard to static electricity, the friction of the gas flow, especially when the gas flow is ejected at a high speed, charges the gas flow, and there is still concern about the electrical effects on the product. . Wherein, the main heating gas flow and scope as the ejection pressure of the preheating gas stream charged gas flow is enough not a concern of electrical influence, specifically to a pressure of 1~3 kgicm ² · G Preferably, the gas pressure from the first nozzle is higher than the gas pressure from the second nozzle. Also, by selecting such a pressure range, It is possible to prevent lowering of the retained energy on the flow side and shorten the soldering time.

Further, the second heating means is preferably formed at least at the tip end of the first chamber, and is made of a member having a heat storage function for transferring heat from the first core heating means. It is preferable that the nozzle member has a nozzle member, and a nozzle orifice is inserted into the nozzle opening to adjust the nozzle diameter. This second heating means is preferably a copper or copper alloy nozzle member.

Further, the first chamber has a gas communication port communicating with the second chamber, and the inert gas supplied to the first chamber is heated and expanded by the first core heating means. The pressure is preferably such that the inert gas supplied to the first chamber 1 is partially supplied to the second chamber via the gas flow port. In this case, the opening diameter of the first nozzle is larger than the opening diameter of the branch supply port of the second chamber, and the first nozzle is sprayed with the heated inert gas from the tip opening of the first nozzle. A part of the inert gas supplied into the first nozzle by the back pressure in the nozzle is preferably supplied to the second nozzle.

In order to achieve a dense, assembling and soldering, soldering is performed in an atmosphere where the adhered molten solder can be slowly cooled with moderate temperature characteristics, and rapidly cooled in an atmosphere at room temperature or below immediately before the start of solidification. It is important to do so. In the present invention, the gas flow is made into an inner / outer double, preheated by the outer preheating gas flow, soldered by the inner main heating gas flow, and then slowly cooled to just before the start of solidification by the outer preheating gas flow to room temperature. Exposure to the following atmosphere allows rapid cooling. When the present invention is applied to soldering of electronic components, the inert gas supplied to the first nozzle is 250 to 100 ° C., particularly 300 to 6 ° C. by the first core heating means. 0 (it is preferable to be heated to TC, and the inert gas supplied to the second nozzle is 100 to 300, particularly preferably 150 to 200 ° C. Further, it is preferable that the flow rate of the inert gas injected from the first nozzle is 1 to 3 ^ // min in order to increase the heat input and shorten the soldering time.

Further, clearance is very important for achieving the effects of the present invention. Therefore, the inner diameter of the tip of the first chamber, which forms the second heating means, and the first core heating The clearance between the outer diameter of the tip-shaped heater as a means and the outer diameter of the tip-shaped heater is set to a size set so that the temperature can be raised to a predetermined temperature after passing the inert gas force passing therethrough. For example, a clearance of 0.1 to 0.15 mm can be adopted. The opening diameter of the first nozzle can be 0.2 to 1 mm to 5, and the opening diameter of the second nozzle can be 2 to 3 mmø.

Further, according to the present invention, there is provided a cylindrical body having a nozzle portion at a front end, wherein a high-temperature gas injection mechanism for heating a gas flow supplied from the rear to a predetermined temperature in the cylindrical body and ejecting the gas flow from the nozzle portion. In the vicinity of the nozzle, a core heat source extending in the axial direction of the cylindrical body via a predetermined clearance with the inner wall of the cylindrical body, and a heat storage cover surrounding the outer periphery of the core heat source and extending in the axial direction forming a part of the cylindrical body It is possible to provide a high-temperature gas injection mechanism comprising: a heating means comprising a heating means, wherein the clearance is set such that a gas flow reaching the upstream of the heating means has a predetermined injection temperature before being fired from the nozzle portion after passing through the clearance.

The cylinder preferably has a flow opening for diverting the supply gas flow to the outside of the cylinder when the back pressure in the cylinder becomes equal to or higher than a predetermined value. Preferably, a temperature sensor is provided in front of the nozzle portion in front of the core heat source to detect a gas flow temperature after passing through the clearance and to control the core heat source temperature.

Further, according to the present invention, in the non-contact soldering method, when supplying an inert gas to the soldering iron and performing heating and jetting, the inert gas is supplied to the first chamber, and the inert gas is supplied to the front of the first chamber. Raising the temperature to a predetermined third temperature through a clearance formed by a core heat source extending in the axial direction near the nozzle provided at the tip and a heat storage cover surrounding the core heat source; An inert gas is supplied through a communication port to a second chamber surrounding the first chamber by a back pressure generated by a temperature rise and expansion of the inert gas, and is located in front of the second chamber. Raising the temperature to a predetermined second temperature by passing through the outer periphery of the heat storage cover,

It is possible to provide a non-contact type soldering method in which a gas flow surrounded by a gas at a second temperature and centered on a gas at a second temperature is injected to a predetermined soldering site. The time for raising the temperature of the inert gas through the clearance between the core heat source and the heat storage cover in the first chamber is preferably set to a time that quickly responds to the intermittent work of soldering. Good.

Rapid cooling line Tsutemoyore exposed to the atmosphere from the molten solder solidified immediately before the start, but melt Handa is releasing latent heat upon solidification, at the same time dissolve the 0 _2, H _2, CO, etc. in the atmosphere However, oxidation and porosity may be caused, and oxidation of solder immediately before solidification is the largest cause of generation of bridges, knuckles, and errata. The low-temperature nitrogen gas atmosphere is set to room temperature, specifically, a temperature of 25 ° C. or lower, but it is preferable to secure a quenching effect. For example, the temperature may be between 120 ° C. and 130 ° C. Also, when the work surface is exposed to a low-temperature nitrogen gas atmosphere, the molten solder is rapidly cooled from the front surface side. It is preferable because a finer rapidly solidified structure can be obtained.

The main heating gas flow generation chamber 1 is preferably formed around the heating element from the viewpoint of manufacturing simplicity, but may be formed inside the heating element. The shape of the nozzle is not particularly limited, but it is preferable to use a diverge X-in nozzle, for example, since it is better to jet the gas stream at a higher speed. The preheating gas flow may be ejected straight around the main heating gas flow, but a spiral fin and a spiral groove are formed on the inner surface of the preheating gas flow generation chamber 1 so that the preheating gas flow is formed into a spiral shape. By swirling, the air in the space surrounded by the preheating gas flow is sucked out, and the main heating gas flow is injected in the downward state, thereby increasing the soldering efficiency of the main heating gas flow. The positional relationship between the tip of the first and second nozzles is

The tip of the second nozzle may be made to protrude from the tip of the first nozzle, or the positional relationship may be reversed. The latter is preferable when the element of the work is small, especially when the element has an ultra fine pitch, for example, when soldering electronic components.

Incidentally, even if the ejection pressure of the main heating gas fluid and the preheating gas fluid is appropriately set as described above, the charging of the gas flow may still remain. Therefore, the main body of the trowel is grounded, and negative charges are electrostatically induced inside the main heating gas flow generation chamber and the preheating gas flow generation chamber to remove the brass charges of the main heating gas flow and the preheating gas flow. It is better to be able to do it. In the present invention, since the soldering portion of the work is preheated by the preheating gas flow, even if the tip is brought into contact with the soldering portion, the temperature drop of the tip is small and the tip is preheated. As a result of being heated by the gas flow and rapidly raising the temperature, the thermal stress of the tip can be reduced.

That is, according to the present invention, when soldering a soldering portion of a work using a soldering iron, the temperature of the tip of the soldering iron is lower than that of the above-mentioned tip and sufficient for preheating the solder. The preheated gas flow is blown around the above-mentioned tip, and the preheated gas flow is blown onto the soldering portion of the work to preheat the preheated gas. Then, the preheated gas is blown out of the preheated work by the tip. It is possible to provide a contact-type soldering method characterized in that the soldering is performed in an atmosphere surrounded by a flow.

In this case, the preheated gas flow reduces the heat cycle of the tip and quickly returns the temperature-reduced tip to a predetermined temperature, and is more effective than the above-described case of forming the inner / outer double gas flow. High temperature is preferred Forces may affect the work and elements (eg, electronic elements) near the soldering site. Therefore, a low-temperature gas flow, which is lower than the preheating gas flow, is sprayed around the preheating gas flow from the tip of the soldering iron, and the pre-heating of the work soldering part and the work near the soldering part at the time of soldering are performed. The element may be protected from the heat of the preheated gas stream with a cold gas stream. Further, according to the present invention, it is possible to provide a soldering iron used in the above-mentioned contact-type soldering method.

That is, according to the present invention, in a soldering iron in which the tip can be heated by the heat generated by the heating element built in the iron body, the tip of the tip is placed around the heating element. A preheating gas flow generation chamber is opened to the periphery to form a preheating gas flow generation chamber, and the heat generated by the heating element generates a preheating gas flow at a temperature lower than the tip chip and at a temperature sufficient to preheat the solder, and It is possible to provide a hornworm-type soldering iron characterized in that it is ejected to the surroundings.

In this case, a low-temperature gas flow generation chamber is formed around the preheating gas flow generation chamber, and the leading end side is opened around the leading end opening of the preheating gas flow. A structure may be adopted in which a low-temperature gas flow lower than the preheating gas flow is generated by convection heat from the generation chamber 1 and heating by Z or radiant heat, and the low-temperature gas flow is jetted around the preheating gas flow.

In addition, if the above-mentioned contact-type soldering iron structure is used, high-temperature inert gas such as high-temperature nitrogen gas is sprayed onto the soldering part when soldering with a soldering robot or an automatic soldering machine. In addition, it is possible to provide an inert gas purge device suitable for protecting the soldering portion from the atmosphere and preheating.

That is, the inert gas purging apparatus according to the present invention has a soldering iron shape as a whole, and has a built-in heating element. A preheating gas flow generation chamber is formed around the heating element while opening the tip side around the tip of the heating element while the heating element can be heated. A high-temperature gas flow is generated by the radiant heat and is ejected forward.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a sectional view showing a principal part of a first embodiment of a soldering iron according to the present invention. FIG. 2 is a sectional view showing a principal part of a second embodiment of the soldering iron according to the present invention. FIG. 3 is a sectional view taken along the line II. FIG. 4 is a diagram for explaining a soldering method using the above-mentioned soldering iron. FIG. 5 is a sectional view showing a first modification of the above-mentioned soldering iron. FIG. 6 is a sectional view showing a second modification of the above-mentioned soldering iron. FIG. 7 is a sectional view showing a principal part of a third embodiment of the soldering iron according to the present invention. FIG. 8 is a sectional view showing a principal part of a third embodiment of the soldering iron according to the present invention. FIG. 9 is a perspective view showing the holder 135 in the soldering iron of FIG. FIG. 10 is a configuration diagram showing a conventional non-contact soldering iron. FIG. 11 is a view showing a preferred embodiment of the inert gas purge device according to the present invention. FIG. 12 is a diagram showing a modification of FIG.

Description of the preferred embodiment

Hereinafter, the present invention will be described in detail based on specific examples shown in the drawings. FIG. 1 illustrates the present invention. A preferred embodiment of such a non-contact soldering iron is shown. The rear end of the iron body 11 is attached to the tip of the iron base by means of a screw or the like, and the iron body 11 is attached to the inner and outer double stainless steel cylinders 12 and 13 and the center. And a rod-shaped alumina ceramic heater (core heating means) 14.

At the tip of the inner stainless steel cylinder 12, a copper first nozzle 19 (also used as a heat storage cover) 19 having an opening diameter of 2 to 3 mm is fitted and fixed, and the inner diameter surface of the first nozzle 19 and the heating nozzle are fixed. —A clearance of 0.1 to 0.15 mm is formed between the outer diameter surface of evening 14 and the outer diameter surface. A stainless steel pipe 61 is inserted into the tip of the first nozzle 19 to adjust the nozzle diameter to 0.5 to 1.0 mm.

In addition, between the first nozzle 19 and the inner stainless steel tube 13 and the heat heater 14, a main heating gas flow having a high temperature enough to melt and soften the solder by heating the heater is generated. Heated gas flow generation chamber 1 (first chamber 1) 17 、 Between inner and outer stainless steel cylinders 12 and 13 Preheat solder at lower temperature than main heated gas flow by heating with convective heat and / or radiant heat The preheating gas flow generation chamber 1 (second chamber 1) 18 that generates a preheating gas flow at a temperature sufficient to perform

A preheat nozzle (second nozzle) 20 that covers the entire outer periphery of the first nozzle 19 is externally fitted to the end of the outer stainless steel cylinder 12.

The base of the trowel has a hollow shape and the inside is a gas supply passage. A first gas circulation port 22 is formed at the rear end of the trowel main body 11 to form a main heating gas flow generation chamber. An inert gas is supplied to one of the seventeen. The gas supply passage may be constituted by a hose or the like supported outside the base of the iron.

Further, a gas flow port 25 is formed on the base side of the inner stainless steel cylinder 13, and a part of the inert gas that has been heated and expanded in the main heating gas generation chamber 17 is generated by the back pressure. The preheated gas flow generation chamber 18 is branched and supplied.

A sensor 27 for detecting and controlling the temperature of the main heating gas flow is attached to the end of the heater 14, and although not shown, the stainless steel cylinders 12 and 13 are grounded. It is connected. In this example, the heating nozzle 14 is heated to a surface temperature of 700 to 900 ° C, and the radiant heat causes the first nozzle 19 to be heated to 300 to 57 (TC, When the inert gas is supplied into the inner stainless steel 12 and reaches the clearance, the temperature is raised to 300 to 600 ° C and expanded two to three times, and the first nozzle 1 is used as the main heating gas flow. At the same time, part of the expanded inert gas is guided to the preheating gas flow generation chamber 18 by its back pressure, where the radiant heat of the first nozzle 19 and the gas itself are Maintained at 150 to 280 ° C by convection heat and injected as a preheating gas flow around the main heating gas flow, so that the main heating gas flow does not lower the temperature and entrains oxygen In addition, pre-heating the soldering part by gas flow You can also.

2 and 3 show a second embodiment of a non-contact soldering iron according to the present invention. The rear end of the iron body 11 is attached to the tip of the iron base 10 by a method such as screwing and screwing. The inner stainless steel tube 13 is supported on the inner surface of the outer stainless steel tube 12 by a spacer piece (not shown). Have been.

The heating heater 14 is supported on the inner surface of the inner stainless steel tube 13 by a metal cover 15, and a plate-shaped spacer 16 is formed at the rear end of the cover 15. Main heating gas flow generation chamber that generates a main heating gas flow that is hot enough to melt and soften the solder by heating the heater between 15 and the inner stainless steel cylinder 13

17 、 Between the inner and outer stainless steel cylinders 12 and 13 Generate a preheated gas flow at a lower temperature than the main heating gas flow and at a temperature sufficient to preheat the solder by heating with convection heat and no or radiant heat. The preheating gas flow generation chamber is 18 times.

A first nozzle 19 made of molybdenum is fitted to the tip of the inner stainless steel cylinder 13, and the first nozzle 19 is projected from a through hole in the tip wall of the outer stainless steel cylinder 12. The tip of the outer stainless steel tube 12 covers the entire outer periphery of the first nozzle 19

The second nozzle 20 is externally fitted. Further, the base 10 has a hollow shape and the inside is a gas supply passage 21, and a first gas circulation port 22 is provided at the rear end of the A second gas flow port 23 is formed in the plate-like spacer 16, and a third gas flow port 24 is formed in the tip of the cover 15. The generated main heating gas flow is guided toward the first nozzle 19. In addition, the gas supply passage 21 may be constituted by a hose or the like supported outside the iron base 10. Further, a fourth gas flow port 25 is formed on the inner stainless steel 13 behind the cover 15 at the end of the outer stainless steel cylinder 12 to form a fifth heated gas flow port 26. A part of the inert gas heated and expanded in the chamber 17 is branched and supplied to the preheating gas flow generation chamber 18 by the back pressure.

At the end of the heater 14, a sensor 17 for detecting the temperature of the main heating gas flow 30 and performing control is attached, and although not shown, a stainless steel 1 2 And 13 are connected to ground.

Next, the soldering method will be described. When soldering is performed in a non-contact manner using the soldering iron of the present example, first, the heating heater 14 is energized, and nitrogen gas is supplied to the gas supply passage 21 in the base 10. The nitrogen gas may be preheated to a predetermined temperature, for example, 40 to 50 ° C. Then, the nitrogen gas is guided to the main heating gas flow generation chamber 17 through the gas flow ports 22 and 23, and is heated to 250 to 600 ° C. by the heating heater 14 so that the main heating is performed. A gas stream 30 is generated, and the main heated gas stream 30 is ejected from the first nozzle 19 via the gas flow port 24. The ejection amount of this main heating gas stream 30 is set to 0.5 to 2.0 liters Z, and the ejection pressure is set to 0.1 to 2.0 kgf / cm ² · G.

At the same time, a part of the nitrogen gas heated and expanded in the main heating gas flow generation chamber 117 is guided by the back pressure to the preheating gas flow generation chamber 118 via the gas flow port 25, and is 1 0 0~2 0 0 ^a C be heated preheat gas flow 3 1 produced by radiant heat from the convection and heat arsenide Isseki 1 4 hot nitrogen gas in the flow generating chamber one 1 7, the gas flow port 2 6 Around the main heating gas flow 30 from the second nozzle 20 through It is squirted over. The ejection amount of this preheating gas stream 31 is set to 0.5 to 2.0 liters Z, and the ejection pressure is set to 0.1 to 2.0 kgf / cm ² · G.

When the preparation is completed, first, a preheating gas flow 31 is blown onto the soldering portion W of the substrate to preheat the soldering portion W, and then the main heating gas flow 30 is blown. 0 is sprayed onto the soldering site W with its surroundings covered by the preheating gas flow 31 as shown in Fig. 3, and it does not scatter around as it is in the past, so the solder melts immediately . Thereafter, the molten solder is slowly cooled by a preheating gas stream 31 until just before the start of solidification, and then rapidly cooled by being exposed to the atmosphere.

According to the experiments conducted by the inventors of the present invention, it took 4 to 5 seconds for the conventional non-contact soldering iron to complete the soldering, whereas the non-contact soldering iron of the present example required 1 second. It was confirmed that the soldering could be completed in a certain degree. Therefore, the non-contact type soldering of the present embodiment can be practically adopted instead of the conventional soldering port bot / soldering in the automatic soldering machine.

Also, when the heat of the molten solder is rapidly absorbed by the surroundings, the molten solder is rapidly cooled as a whole, and fine quenched crystals, fine columnar crystals, and fine free crystals are formed, but the columnar crystals are crystal columns. Grain boundaries containing impurities and gases are likely to be generated in parallel with the crystal, and the free crystals are likely to contain flux gases and impurity gases. On the other hand, since the main heating gas flow 30 and the preheating gas flow 31 with appropriate pressure are blown to the molten solder, the solder and flux do not flow out of the soldering portion W, and the molten solder force is applied. Pressurizes and releases gas, eliminating bubbles and gas holes. In addition, the dendrites can be filled with the molten solder by this pressurization, and microporosity and macroporosity (porosity) can be prevented, resulting in a dense crystal structure.

Therefore, the whole of the molten solder is rapidly cooled, so that the distance between the liquidus and solidus of the molten solder is substantially reduced, and the pressurizing effect is exerted, resulting in macro-segregation (Pb, Sn, etc.) and micro-segregation. Dendritic crystals, layered structure, nucleated structure, etc., of segregation are reduced, impurities and gas are reduced, and solidified solder with fine crystal structure can be obtained.

In addition, the ejection pressure of the main heating gas flow 30 and the preheating gas flow 31 is set appropriately. Therefore, electrification due to gas friction is unlikely to occur, and since the iron body 11 is grounded, the main heating gas flow generation chamber 117 As a result, the positive charge of the main heating gas flow 30 and the preheating gas flow 31 can be removed by electrostatically inducing a negative charge inside the flow generation chamber 18, and as a result, the electrostatic breakdown at the soldering site W is reduced. The fear can be reliably eliminated.

FIG. 5 shows a first modification of the above embodiment. In this example, the tip of the second nozzle 20 protrudes forward from the tip of the first nozzle 19, and the inner stainless steel tube 13 is made of beryllium copper, chromium copper, or another alloy having good heat conductivity. The inner alloy tube 13 and the first nozzle 19 are integrally formed, and the second nozzle 20 and the outer stainless steel tube 12 are integrally formed. The first nozzle 19 employs a divergent nozzle structure in which the inner surface expands in an arcuate cross section. Dimensionally, the inner diameter of the tip of the first nozzle 19 is set to 0.1 to 0.5 mm, the inner diameter of the second nozzle 20 is set to 0.5 to 4.0 mm, and A flat surface 20a of 1-2 mm is formed on the inner surface of the tip portion of the nozzle 20 to stabilize the preheating gas flow.

In this example, the die nozzle is used as the first nozzle 19, so that a high-speed main heating gas flow can be obtained by the structure, and the tip of the second nozzle 20 is connected to the first nozzle 19. Since the preheating gas flow and the high-speed main heating gas flow accelerate each other, the main heating gas flow and the high-speed preheating gas flow are further increased. As a result, even after a certain distance between the tip of the first and second nozzles 19 and 20 and the work soldering site, Thermal decay of the main heating gas flow and the preheating gas flow until reaching the work soldering site is small, and the consumption of nitrogen gas (or air) can be suppressed.

FIG. 6 shows a second modification. In this example, a hollow ceramic heater is used as the heater 14, and a main heating gas flow generation chamber 117 is formed inside the heater 14. A coil-shaped material 17a made of a molybdenum-based alloy or a tungsten-based alloy is housed in the heater 14 to impart a swirl to the main heating gas flow to reduce heat unevenness of the main heating gas flow. ing. Note that the second nozzle 2 A spiral fin or a spiral groove is formed on at least one of 0 and Z or the outer surface of the outer cylinder 12 and the first nozzle 19 and Z or the outer surface of the inner nozzle 13 so as to impart a swirl to the preheating gas flow. Is also good.

FIG. 7 shows a third embodiment of the present invention. In the figure, the soldering iron body 30 and the grip portion (trowel base) 31 and the force, and the iron body 30 have a heating heater (for example, a round barbed aluminum nitride The tip of the heater 32 is inserted into the hole of the tip holder 33, the tip 34 of the tip holder 33 is fixed to the tip 34, and the heat of the heating heater 32 is generated. The tip 34 is transmitted to the tip 34 to be heated.

The rear end of the heater 32 is inserted into and held by a central hole of a holder 135 built in the tip of the grip portion 30, and the heating heater 32 is provided with a temperature sensor (not shown). ) Is attached. An auxiliary heater for controlling the temperature of the preheated gas flow may be installed. A plurality of nitrogen gas supply holes are formed in an annular shape in the holder 35, and the end of a nitrogen gas supply pipe 36 inserted into the grip portion 30 is connected to the holder 35, and a heater 3 2 A power line 32a extends rearward in the nitrogen gas supply pipe 36 from the rear end.

Further, a first protective cover 37 is fixed to the end of the grip portion 30. The first protective cover 37 covers the periphery of the heating heater 32 and is provided between the tip holder 33 and the heating cover 32. A predetermined gap, for example, 1 mm, is left to the front end side with a predetermined gap, and the front end is opened around the front end tip 34, thus constituting the preheating gas flow generation chamber 38. It is preferable that the tip of the first protective cover 37 extends as close to the tip 34 as possible, so that it does not touch the workpiece during soldering.

Next, the method of use will be described. When soldering is performed using the soldering iron of this example, first, the heater 32 is energized to heat the tip chip 34 at 280 to 38 (while heating to TC, while nitrogen gas is applied to the soldering iron). The supply pipe 36 is supplied with nitrogen gas having a pressure of 1.0 to 5.0 kg / cm ² , a flow rate of 4 liters Zmin, and a purity of 99 to 99.9%. Good, intermittent supply, then preheating gas flow The nitrogen gas passing through the chamber 38 is heated to 200 CC to 25 O CC by the radiant heat of the tip 34 due to the heat generated by the heater 32, increasing its volume and discharged forward as it is. You. The flow rate and pressure of the nitrogen gas can be adjusted by setting the inner diameter and number of the nitrogen gas supply holes of the holder 135. It is also possible with an external pressure regulator or flow regulator.

When the preparation is completed, first, a preheating gas flow is blown to the soldering portion of the board for 2 to 5 seconds to preheat the soldering portion, thereby activating a low residue flux at the soldering portion. In addition, the tip 34 may be brought into contact with the soldering portion at the same time as the preheating gas flow is sprayed. When the concentration of O _{2 is} 5 ppm or less, flat soldering is possible.

Next, in about 0.3 to 8 seconds, the tip 34 is brought into contact with the soldering site and heated to supply the low-residue flux-containing threaded solder, which melts at the soldering site in a preheated gas flow atmosphere. A solder pile is formed. Next, the tip 34 is separated from the soldering site, and the molten solder is exposed to the atmosphere of the preheated gas flow, while rapidly cooling by blowing nitrogen gas at room temperature from the back surface of the substrate.

Then, the heat of the molten solder is rapidly absorbed into the surroundings, and the molten solder is rapidly cooled as a whole, so that fine quenched crystals, fine columnar crystals, and fine free crystals are formed. Columnar crystal grain boundaries is likely to occur including parallel impurities or gases into crystalline pillar, and the pressure 1 of hot nitrogen gas 6 5 to free crystals of the flux gas and impurity gas. To 0~5. 0 kg / c ^z Thus, the molten solder is pressurized and gas is released, so that bubbles and gas holes can be eliminated. In addition, the pressurized high-temperature nitrogen gas 65 can be used to pressurize and fill the gaps between the molten metals with the molten solder melt, preventing micro-macroporosity (porosity) and achieving a dense crystal structure. Become.

Therefore, the whole of the molten solder is rapidly cooled, so that the distance between the liquidus and solidus of the molten solder is substantially reduced, and a pressurizing effect is exerted, and macro-segregation (Pb, Sn, etc.) The solidified solder of fine crystal structure with few impurities and gas can be obtained by reducing the segregation of dendrite, lamellar structure, nucleated structure, etc. In addition, the solder flux is preheated to activate the flux and prevent the flux-solder ball from scattering, so that a smooth and good soldering operation can be performed. Preheating the electronic board before contacting the board, mitigating local and rapid temperature rise (heat shock) of the electronic board and preventing thermal destruction of electronic components, as well as flux, electronic board and supplied solder The wire can also be preheated, so that the hot brittleness of the solder layer can be prevented.

Also, since the solder and flux can be preheated with high-temperature nitrogen gas, the amount of heat stored in the tip of the soldering iron is small, and even if the tip of the chip is extremely fine, sufficient amount of heat can be used for soldering, resulting in low-temperature soldering. Can be achieved. Further, since the soldering iron chip is in a non-oxidizing atmosphere, the oxidation of the chip is prevented, the wettability of the molten solder can be improved, and the chip cleaning is almost unnecessary, and the chip life can be greatly improved.

FIG. 8 shows a fourth embodiment of the present invention. In this example, a second protective cover 39 is fixed to the tip of the grip portion 30 outside the first protective cover 37, and the second protective force bar 39 is a first protective cover 3 7 is airtightly covered with a predetermined gap, for example, a gap of mm, and extends to the front end, and the front end is opened near the front end of the first protective cover 37, thereby generating a low-temperature gas flow. A chamber 40 is configured. As shown in FIG. 8, a nitrogen gas supply hole is formed in the holder 135 such that the nitrogen gas is supplied to the low-temperature gas flow generation chamber 140 so that the nitrogen gas is also supplied to the holder 135. In this example, soldering is performed in substantially the same manner as in the above-described second embodiment. The substrate is exposed to the low temperature generated at 0, for example, the nitrogen gas atmosphere at room temperature. : Prevents child parts from receiving thermal alum.

FIG. 11 shows a preferred embodiment of an inert gas purging apparatus to which the concept of the present invention is applied. The inert gas purging device comprises a main body 30 and a grip portion 31. The main body 30 has a built-in heater (for example, a round barbed aluminum nitride heater) 32, and a tip of the heater 32. Is a heat-insulating member made of a copper-based alloy with good thermal conductivity. Body) 33 is inserted into the hole, and the heat generated by the heater 32 is transmitted to the heat retaining member 33 to heat the heat retaining member 33.

The rear end of the heater 32 is inserted and held in the center hole of a holder 35 built in the tip of the grip portion 30, and a temperature sensor 39 is attached to the heater 32. I have. A plurality of nitrogen gas supply holes are formed in an annular shape in the holder 35, and the end of a nitrogen gas supply pipe 36 passed through the grip portion 30 is connected to the holder 135, and a heater is provided. The power line 32 extends from the rear end of the line 32, and the nitrogen gas supply pipe 36 extends rearward in the line.

Also, a first protective cover 37 is fixed to the end of the grip portion 30. The first protective cover 37 covers the periphery of the heater 32 and is provided between the first protective cover 37 and the heat retaining member 33. A predetermined gap, for example, a gap of l mm is extended to the front end side, and the front end is opened to surround the front end of the heat retaining member 33, thereby forming a high temperature gas flow generation chamber 38.

In the inert gas purging equipment of this example, when soldering with a soldering port bot and an automatic soldering machine, high-temperature inert gas is blown to the soldering area to protect the soldering area from the atmosphere. Ideal for preheating as well as for heating.

FIG. 12 is a modification of the embodiment shown in FIG. 7, in which a cover 37 is attached to an existing soldering iron so as to cover a portion of the heating heater 33, and a gas is attached to the cover 37. The supply hose 62 is connected to achieve the same operation and effect as in FIG.

Industrial applicability

According to the present invention, of the inner and outer dual gas flows ejected from the tip of the soldering iron, the inner gas flow is heated within a predetermined clearance, and the expansion is used to reduce the outer gas flow. Since the gas flow is generated, the gas flow can be heated to a predetermined temperature without increasing the temperature of the heating means, so that not only continuous soldering but also intermittent soldering can be performed in a short time. In addition, after preheating with the outer preheating gas flow, soldering was performed with the inner main heating gas flow in the atmosphere surrounded by the outer preheating gas flow, so that the The heat of the main heated gas stream is not scattered to the surroundings. In addition, it can be efficiently transmitted to the soldering part of the work, and can be soldered in a short time without contact, that is, without using a tip chip.

As a result, it is possible to prevent the electrical characteristics of the product from deteriorating due to the contact of the tip tip, and to properly set the ejection pressure of the main heating gas flow and the preheating gas flow, and to ground the iron body, This can reliably prevent electrification of the product, thereby preventing electrostatic breakdown of electronic components and ensuring the electrical characteristics of the product.

In addition, since the soldering can be performed in an atmosphere in which the molten solder is slowly cooled, the molten solder has a preferable surface tension and exhibits a substantially hemispherical shape in a raised state. In addition, immediately before the start of solidification of the molten solder, it is rapidly cooled in an atmosphere at room temperature or lower, and it is possible to give the molten solder a directional solidification in which the distance between its liquidus and solidus is substantially reduced. This allows the solder to have a finely solidified structure.

As a result, there is no solder balls, bridges, or solder splattering, and it is dense, has very few segregation of Pb and Sn, has excellent heat shock resistance, and has high quality, high quality non-oxidizing and non-cleaning. Soldering can be performed.

Further, according to the present invention, a preheating gas flow is injected around the tip tip, a low-temperature gas flow is injected as necessary around the tip, and the soldering portion is preheated with the preheating gas flow. Since the tip is used for soldering, there is little change in temperature of the tip due to contact with the soldered part, and the tip is heated by the preheating gas flow, resulting in almost all thermal stress on the tip Without this, the life of the tip can be greatly improved.

Claims

Scope of word blue

1. A first chamber that generates a main heated gas flow having a first nozzle at the tip, and a second nozzle that opens and covers the outside of the first nozzle at the tip, wherein the first chamber is Nozzle means surrounding at least a second chamber for producing a preheated gas flow;

A first core having a heat source for heating an inert gas ejected from a nozzle orifice through the clearance in the first chamber near the first nozzle in the center with an inner wall provided therebetween; Heating means, and at least a tip portion of the first chamber, forming a heat source surrounding the heat source of the first core heating means, and storing heat between the first chamber and the second chamber; Heating means for heating an inert gas, the heating means comprising at least a second heating means,

An inert gas supply means for communicating with the first chamber and supplying an inert gas, and branching and supplying the inert gas supplied to the first chamber to a second chamber; ,

While the inert gas supplied to the first chamber 1 rises to a predetermined heating temperature while passing through the clearance, the inert gas that rises in temperature and expands in the first chamber is reduced by its back pressure. A non-contact type soldering iron that branches into the second chamber.

2. The non-contact soldering iron according to claim 1, wherein the first core heating means has a clearance between an inner wall and a first chamber, and is an inserted rod head.

3. The first core heating means is A ^ ₂ 0 ₃ rods made Johi Isseki, soldering iron noncontact claim 2.

4. The non-contact type device according to claim 1, wherein the second heating means is formed at least at a distal end portion of the first chamber, and is made of a member having a heat storage function for transferring heat from the first core heating means. Soldering iron.

5. The non-contact type according to claim 1, wherein the second heating means is a nozzle member having a heat storage function, and the nozzle opening can be adjusted by inserting a nozzle into the nozzle opening. Soldering iron.

6. The non-contact soldering iron according to claim 5, wherein the second heating means is a copper or copper alloy nozzle member.

7. When the first chamber has a gas communication port communicating with the second chamber, and the inert gas supplied to the first chamber is heated and expanded by the first core heating means. The non-contact soldering iron according to claim 1, wherein a part of the inert gas supplied to the first chamber is supplied to the second chamber through the gas flow port due to the back pressure. .

8. The opening diameter of the first nozzle is larger than the opening diameter of the branch supply port of the second chamber "" ^^. 2. The non-contact soldering iron according to claim 1, wherein the inert pressure supplied into the first nozzle by the back pressure in the nozzle of (1): a part of the raw gas is supplied to the second nozzle.

9. The inert gas supplied to the first nozzle is heated by the first core heating means to 250 to 100 ° C, particularly to 300 to 600 ° C. The non-contact soldering iron described in 1.

10. The non-contact type of claim 1, wherein the inert gas supplied to the second nozzle is heated to 100 to 300 ° C., particularly to 150 to 200 ° C. 10. Soldering iron.

1 1. Clearance between the inner diameter of the tip of the first chamber forming the second heating means and the outer diameter of the tip of the sigma heater serving as the first core heating means passes therethrough. The non-contact soldering iron according to claim 1, wherein the non-contact soldering iron is set so that the temperature can be raised to a predetermined temperature after passing the inert gas.

12. The non-contact soldering iron according to claim 11, wherein the clearance is 0.1 to 0.15 mm.

1 3. The inert gas pressure from the first nozzle and the second nozzle is 1-3 kgί / cm ² · G, and the gas pressure from the first nozzle is lower than the gas pressure from the second nozzle. The non-contact soldering iron according to claim 1.

14. The flow rate of the inert gas injected from the first nozzle is 1 to 3 ^ minutes. The non-contact soldering iron according to claim 1.

15. The non-contact soldering iron according to claim 1, wherein the first nozzle opening diameter is 0.2 to l mm ø.

16. The non-contact soldering iron according to claim 15, wherein the opening diameter of the second nozzle is 2 to 3 mm ø.

17. A high-temperature gas injection mechanism that has a nozzle at the front end and heats a gas flow supplied from the rear to a predetermined temperature in the cylinder and ejects the gas from the nozzle, near the nozzle. Heating means comprising: a core heat source extending in the axial direction of the cylindrical body through a predetermined clearance with the inner wall of the cylindrical body; and a heat storage cover surrounding the outer periphery of the core heat source and forming a part of the cylindrical body and extending in the axial direction. A high-temperature gas injection mechanism, wherein the clearance is set such that the gas flow reaching the upstream of the heating means has a predetermined injection temperature before passing through the clearance and before firing from the nozzle portion.

18. The high-temperature gas injection mechanism according to claim 17, wherein the cylinder has a flow opening for dividing a gas flow supplied to the outside of the cylinder when the back pressure in the cylinder becomes equal to or more than a predetermined value.

19. The high-temperature gas injection mechanism according to claim 18, further comprising a temperature sensor in front of the nozzle portion of the core heat source, detecting a gas flow temperature after passing through the clearance, and controlling the core heat source temperature.

20. In the non-contact soldering method, when supplying an inert gas to the soldering iron and heating and injecting it,

An inert gas is supplied to the first chamber, and a predetermined first gas is passed through a clearance formed by a core heat source extending in the axial direction near the nozzle provided at the front end of the first chamber and a heat storage cover surrounding the core heat source. Raising the temperature to a temperature,

The inert gas is supplied to the second chamber surrounding the first chamber through a communication port by the back pressure generated by the temperature rise and expansion of the inert gas in the first chamber. Raising the temperature to a predetermined second temperature by passing through the outer periphery of the heat storage cover positioned in front of the chamber.

The gas flow surrounding the gas at the first temperature and surrounded by the gas at the second temperature is divided by a predetermined half. A non-contact type soldering method that sprays onto the welding area.

2 1. The time to raise the temperature of the inert gas through the clearance between the core heat source and the heat storage cover in the first chamber quickly responds to the intermittent work of soldering. 20. The non-contact soldering method according to claim 20, wherein the time is set.