JP2000244109A - Partial soldering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably solder without causing short circuits at small soldering spots and to minimize thermal effects imparted to components mounted on a printed board by heating a solder for infiltration, while bringing only the lands of the printed board into contact with the solder, when soldering is performed on the printed board using a partial soldering device. SOLUTION: A soldering nozzle 3 is made block- or plate-shaped, and solder holes 4 having openings to the upper surface of the nozzle 3 are formed. The openings are made to correspond to the locations and shapes of lands 2 formed on a soldering board 25. In order to make fine soldering possible using this nozzle 3, a fused solder squeegee, a level control tank, an antioxidant cover, and a component pressing rod are provided additionally. As a result of this arrangement, a small portion of solder can be supplied, and the solder surface is stabilized even if a solder pool moves vertically. Furthermore, no oxide film is formed, and the lifting of components attributable to the smallness of the diameter of each nozzle can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for partially heating and soldering a printed circuit board on which electronic components are mounted.

[0002]

2. Description of the Related Art In a soldering apparatus using a solder tank, when a soldering nozzle for bringing solder into contact with a substrate is provided in the solder tank in a shape suitable for soldering a minute portion, the soldering nozzle is connected to the soldering nozzle. A mechanism for supplying solder is disclosed in Japanese Patent Application Laid-Open Nos. Hei 6-260753 and Hei 8
-279675 or Japanese Patent Application No. 9-182948. That is, a jet screw, a flow tube, and a soldering nozzle are housed in a solder bath containing molten solder, a motor is attached to the jet screw, and the flow tube wraps the jet screw at one end and connects the jet nozzle to the other end. The soldering nozzle is connected to an introduction pipe provided in a pair with the jet nozzle. Further, the inner surface of the soldering nozzle is made to be a surface adapted to the solder, or a solder pool surrounding the soldering nozzle and filling the upper end of the nozzle with the solder is provided. Due to these, various problems arising in the partial soldering of fine patterns on the substrate, such as the soldering nozzles with minute shapes, whose solder surface is not stable, and the solder flowing out of each soldering nozzle This will eliminate unevenness, thermal degradation of adjacent mounted components, and the like.

[0003]

It is an important point of soldering that in any soldering apparatus for printed wiring boards, the amount of solder supplied to the board land is appropriate and always stable. ing. In the soldering method according to the above configuration, when the supply of the solder stably flowing out of all the soldering nozzles is stopped from the inlet pipe and the solder liquid level of the solder pool is lowered, the shape and size required for the nozzle upper end are required. Build a state that maintains the quality. At this time, if the soldering nozzle is composed of a plurality of thin tubes, the arrangement of adjacent nozzles cannot be close to less than twice the wall thickness of the tube, so it is necessary to prepare an appropriate amount of solder at an appropriate position. At the same time, thin tubes with thin wall thickness cannot maintain the temperature of the solder inside, causing a rapid drop in temperature. Remains around the opening and hinders soldering.

[0004] When the solder level of the solder pool is lowered, solder remains on the upper end surface of the soldering nozzle, and it is impossible to form minute solder surfaces independent of each other.

Further, when the pool body is driven up and down in order to raise and lower the solder liquid level of the solder pool, the solder liquid level of the entire solder tank changes greatly and becomes unstable, and excessive solder weight is applied when the pool rises. For this reason, the vertical drive device must be configured with a strong mechanism.

[0006] In addition, the vertical drive of the pool causes the accumulation of the entrainment of the solder oxide film between the solder tank and the solder tank, thereby increasing maintenance such as elimination and cleaning.

In addition, when fine soldering nozzle openings are provided corresponding to the soldering portions of the electronic components mounted on the board and the board lands, the component leads and the like come into contact with the outer edges of the soldering nozzles. There has been a tendency for the adhesion between the component and the substrate to be impaired and for the component to float.

The present invention has been made to solve these problems, and in a partial soldering apparatus using a nozzle having a fine shape, an appropriate amount of solder can be prepared at an appropriate position even if it is finer. The solder temperature is easy to maintain, no solder is left on the edge of the soldering nozzle at the time of soldering, and even if the solder pool is moved up and down, the solder liquid level of the solder tank that holds it is stabilized, and the up and down drive mechanism is also Providing a mechanism that can reduce the size and weight or eliminate the up and down movement of a large solder pool, prevent oxidation of the solder surface of the solder tank including the surroundings of the pool, and prevent floating of components that are likely to occur due to a small soldering nozzle It is intended to be.

[0009]

In order to achieve the above-mentioned object, in a partial soldering apparatus according to the present invention, soldering nozzles are grouped, and a soldering nozzle as a soldering nozzle corresponding to a land of a substrate is formed in one block. It has a plurality of holes.

In addition, a plurality of solder holes are made in a thin plate,
Provide an outer edge wall around them or cover the solder container,
A soldering nozzle can also be used.

[0011] In the partial soldering apparatus using the jet solder bath, the solder hole provided in the soldering nozzle may have a lower end opened to the inside of the introduction pipe or may not be opened to the inside of the introduction pipe.

Further, in a partial soldering apparatus using a jet solder bath, a mechanism for raising and lowering a soldering nozzle integrated with an introduction pipe is provided.

It is effective to provide a molten solder squeegee that slides along the upper surface of the soldering nozzle.

Further, a solder level control tank for the solder tank is provided. The tank has a lower opening submerged in the solder and a liquid level adjusting port through which gas or liquid flows in and out is separately provided.

It is effective to provide the solder level control tank on the lower surface of a vertically moving solder pool or soldering jig.

It is preferable to provide an antioxidant cover provided with a valve for covering the solder surface excluding the soldering portion of the substrate in the solder bath and blocking the outside air, and adjusting the internal pressure and the external pressure to a constant value.

It is preferable to provide a holding rod which presses a component mounted on the soldered board with a spring or the like in a direction in which the mounted part is brought into close contact with the board.

A leveling bolt for adjusting the pressure of the holding rod and a floating detection switch for detecting the holding position may be provided in accordance with the holding rod.

[0019]

In the partial soldering apparatus constructed as described above, first, the solder pool filled with solder at the position for accommodating the soldering nozzle rises and covers the soldering nozzle with solder. Alternatively, in a mechanism in which the solder pool is omitted, a soldering nozzle integrated with the introduction pipe lowers the upper end thereof below the liquid level of the solder bath solder.

When the soldering nozzle is provided with a solder hole in the plate surface, if the solder level is raised to the same level or higher than the upper surface of the soldering nozzle, if the plate thickness of the solder hole opening is thin, Due to the function of the surface tension of the solder, a fine and spherical solder corresponding to each land is obtained.

In the case where the soldering nozzle is provided as partial soldering in a jet solder bath, if the other end of the solder hole opened on the upper surface of the nozzle is open inside the inlet tube, the solder in the inlet tube is opened. Is guided to the upper surface of the soldering nozzle through the solder hole. If the inner surface of the solder hole is adapted to the solder, the finer the horizontal cross-sectional area, the stronger the surface tension, and the more difficult it is for the solder to pass through the upper end opening. Therefore, if the upper end opening is covered with solder by the function of a solder pool or the like, the surface tension does not work and the passage of the solder in the solder hole becomes easy.

Similarly to the above, when the soldering nozzle is provided as partial soldering in the jet solder bath, if the other end of the solder hole opened on the upper surface of the block is not opened inside the inlet tube, the upper end is formed. When the opening is covered with solder by a function such as a solder pool, the solder is guided to the solder hole.

Next, the solder pool is slightly lowered, or the soldering nozzle is slightly raised, so that the tip of the soldering nozzle is at the same level as or slightly higher than the surrounding solder surface. A molten solder squeegee is slid to obtain a required size of molten solder having its surface held horizontally at a specific position on the upper surface of the soldering nozzle.

As the solder pool or the soldering nozzle moves up and down, the solder liquid level in the solder tank rises and falls. By letting a fluid having a lower specific gravity than the solder, such as an inert gas, flow into and out of the solder liquid level control tank through the liquid level adjustment port, the solder is sucked into the tank through the opening, or is discharged out of the tank to reduce the liquid level. Keep it constant or control it to an arbitrary height.

A buoyancy, which is increased or decreased by providing a solder level control tank below the solder pool or the soldering nozzle and allowing a fluid to flow in and out of the level adjusting port in the tank,
It is used to help up and down drive.

When a specific portion of the solder surface is covered with the antioxidant cover, the oxidation of the solder surface does not progress even if there is a solder pool or the like moving up and down, and an oxide film adheres to the side wall of the solder pool or the like. No deposition occurs.

A board mounting component is brought into close contact with the board by a holding rod with a leveling bolt for adjusting an appropriate pressure, and soldered. If a component floats, it is detected by the float detection switch.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described with reference to the drawings. In FIG. 1, the shape of a soldering nozzle provided in a solder tank 1 as a partial soldering device is changed to a plurality of lands 2 on a substrate surface to be soldered. A plurality of solder holes 4 having positions and sizes corresponding to the respective lands 2 as openings are provided on the upper surface of the soldering nozzle 3 with a surface having a surface having a corresponding position and size as an upper surface.

In the embodiment shown in FIG. 2, fine solder corresponding to lands is formed on a plate surface 28 having an outer edge wall 29 by a soldering nozzle 3 having a solder hole 4 with a reduced thickness at its opening. A surface 30 is prepared. Also, when soldering,
The storage recess 31 that can store the already mounted components on the board is
8.

In the embodiment shown in FIG. 3, the solder hole 4 provided on the upper surface of the soldering nozzle 3 in the embodiment shown in FIG. It is open to the inside 5 of the tube.

In the embodiment shown in FIG. 4, the lower end of the solder hole 4 provided on the upper surface of the soldering nozzle 3 in the embodiment shown in FIG.

In the embodiment shown in FIG. 5, a soldering nozzle 3 and an inlet pipe 7 connected to the soldering nozzle 3 are provided with a nozzle up / down mechanism 8 which can move up and down integrally.

In the embodiment shown in FIG. 6, when the solder liquid level 27 around the soldering nozzle 3 is equal to or lower than the upper surface of the soldering nozzle 3, the solder is moved along the upper surface of the soldering nozzle 3. A solder squeegee 9 is provided.

In the embodiment shown in FIG. 7, a liquid level control tank 10 is provided in the solder tank 1. The liquid level control tank 10 is provided with an opening 11 in the solder 12 accommodated in the solder tank 1 and also provided with a liquid level adjusting port 13 through which gas or liquid flows in and out.

In the embodiment shown in FIG. 8, the liquid level control tank 10 of the embodiment shown in FIG.

In the embodiment shown in FIG. 9, the antioxidant cover 1 covers a portion of the solder surface in the solder bath 1 other than the portion in contact with the substrate, and blocks the solder surface 15 and the outside air 16 at that portion.
7 is attached. An introduction port 18 is provided in a part of the antioxidant cover 17 and a pneumatic valve 19 is connected so that the pressure and the atmospheric pressure in the antioxidant cover 17 are constant.

In the embodiment shown in FIG. 10, a holding rod 21 for holding a component 20 to be soldered mounted on a substrate is provided, and a spring or the like is provided on the holding rod 21 so as to press the component 20 in a direction in which the component 20 comes into close contact with the substrate 25. Elastic body 22 is attached.

In the embodiment shown in FIG. 11, of the embodiment shown in FIG. 9, a leveling bolt 23 for adjusting the position and pressure at which the holding rod 21 pushes the component 20 is attached. A floating detection switch 24 for reading the position is provided.

[0039]

Since the present invention is configured as described above, it has the following effects.

The solder hole provided on the upper surface of the soldering nozzle with its upper end opened may have a fine shape, or the opening of an adjacent solder hole may be located at a distance of, for example, 1 mm or less. It is possible to accurately determine the shape and individually pierce the corresponding lands.
In other words, the plurality of lands serving as soldering locations around the area are not brought into solder contact with the solder in one nozzle. Also, compared with a partial soldering nozzle which is formed by bending and welding a plate material, a required number and size of solder holes having an optimum size and shape can be easily formed at an arbitrary position on the block upper surface or the plate surface of the nozzle. It became so. Therefore, it is possible to provide a solder hole in a more accurate and precise shape corresponding to the land as compared with the case where the soldering nozzle is formed of a collection of thin tubes. Even when the solder level on the nozzle is higher than the surrounding solder liquid level, the specific heat of the block-shaped or plate-shaped nozzle is high and does not cause a rapid temperature drop. At this time, the solder around the nozzle opening does not cling to the solder due to the viscosity of the solder generated when the solder is formed of a set of thin tubes. Once the solder hole is covered with solder, solder is introduced from the lower or upper part, and then the molten solder squeegee is slid over the upper surface of the nozzle to scrape off excess solder,
It is now possible to prepare a plurality of solders of a required size at required positions on the upper surface of the nozzle while maintaining a constant temperature.

Since the prepared solder is sufficiently small corresponding to each land of the substrate, when the soldering substrate comes into close contact with the solder surface, only the land, which is the soldered portion, is heated through the solder. start. At this time, since the solder in the solder holes is about to be made small by the action of the surface tension, no bridge occurs between the solder in the adjacent solder holes. Also, no solder balls are generated. When the heating has progressed enough to reach the appropriate temperature,
The solder infiltrates the component leads and the lands, and the heating ends.

As described above, only a necessary portion is heated in a dot shape to perform soldering. Therefore, the soldering apparatus using the nozzle does not go over the resist on the substrate and does not heat the unnecessary portion. For this reason, several characteristics can be seen as compared with conventional planar heating such as partial soldering. First, thermal effects on soldered components and on adjacent components can be minimized. With a partial soldering device using a flow soldering mechanism, soldering can be easily performed even in a location where overheating is difficult. In addition, soldering in a narrow pitch and narrow pattern such as a multi-pole connector, which tends to cause a short circuit, has been facilitated.

When compared with a soldering robot using a soldering iron or a heating beam, the soldering ability using the nozzle for performing simultaneous heating on all points on one plane of the substrate is the same, although the solderability at the minute place is the same. The attachment device showed a dramatic improvement in efficiency as compared to the soldering robot that heats and melts one by one. Also, in terms of quality, these robots of the sequential processing type need to heat up the soldering points in a short time in order to increase the efficiency, and it is necessary to pay attention to the magnitude of the thermal shock to the parts. The soldering apparatus using the nozzle, which does not accumulate time, can perform reasonable heating within the allowable temperature and the allowable time of the component. As a method to increase the productivity of the robot, a method of moving the iron tip in a straight line and continuously heating a plurality of soldering points may be performed.
There is a danger of lead bending. The soldering device using the nozzle has solved this fear.

Alternatively, with respect to a partial soldering mechanism for applying cream solder and locally heating with hot air, dripping or thinning of the cream solder, a short circuit or a solder ball associated therewith is likely to occur. In order to overcome these problems, a high level of knowledge and experience is required for the operation technology of the apparatus. In addition, in this mechanism, the supply and heating of the cream solder are separate processing steps, and both require precise equipment. The soldering device using the nozzle, which performs point heating using molten solder, has stable physical properties as a liquid in all soldering processes, ie, heating of the soldering location, solder infiltration, and fillet formation. It makes the most of the surface tension of molten solder. As a result, short-circuits and solder balls did not occur, and a solid fillet with an appropriate amount of solder could be uniformly formed. In addition, in this apparatus, in which solder supply and heating proceed in the same process, the simplification of the mechanism and the easiness of drive control have become possible, and the equipment cost has been reduced.

In consideration of the instability of the post-processing and the low productivity, as in the past, including the manual soldering, the tendency to adopt heat-resistant parts and collectively solder them in a reflow furnace has been increasing in recent years. I have. However, a material such as a connector that can withstand the high temperature of reflow causes an increase in cost. If the original function of the component is considered to be cost, a soldering device using the nozzle can suppress an increase in cost for reflow.

In the partial soldering in the jet solder bath, in order to introduce solder into the soldering nozzle, it is necessary to cover the upper end of the nozzle with solder as described above. In other words, in order to flow and supply the solder having a uniform and constant temperature into the fine solder holes, the surface tension generated on the inner surface is an obstacle. This problem is solved by covering the upper and lower openings with solder. Therefore, in addition to providing a solder pool at a position for accommodating the soldering nozzle, the soldering nozzle integrated with the introduction pipe can be lowered below the solder surface to easily cover the upper end of the soldering nozzle with solder. .

After the upper surface of the fine soldering nozzle is covered with solder, when the solder liquid level moves to a position below the upper surface of the soldering nozzle, the solder remains on the upper end of the nozzle or in the adjacent nozzle opening. Also, even if it is stretched over or fits inside the upper end of the nozzle, it remains in a dome-shaped bulge by the action of surface tension. A molten solder squeegee sliding along the top of the nozzle removes these excess solder.

A solder pool or a soldering nozzle which is immersed in the solder contained in the solder tank and moves up and down violently raises and lowers the liquid level of the solder in the surrounding solder tank as the nozzle moves up and down. The change in the vertical movement amplitude of the liquid surface is inversely proportional to the ratio of the upper area of the solder bath solder and the solder pool or the soldering nozzle in the solder bath. Therefore, in order to stabilize the solder liquid level of the solder tank, it is necessary to prepare a solder pool having a larger upper area for a solder pool or a soldering nozzle having a fixed upper area. This increases the size of the soldering equipment and increases the amount of solder to be accommodated. Therefore, a solder level control tank is provided. By adjusting the pressure in the tank, the solder flows into and out of the tank from the opening under the tank, so that the liquid level of the solder in the solder tank can be arbitrarily controlled. When a gas is used to adjust the pressure in the tank, oxidation of the solder surface in the tank can be prevented by using an inert gas or air that is cut off from the outside air.

The more the solder pool or soldering nozzle immersed in the solder contained in the solder tank and moves up and down is exposed above the surrounding solder liquid level, the greater the load applied to the mechanism for maintaining its position. The weight of the solder contained therein, as well as the weight of the solder pool or the like constituting the exposed portion, becomes a large load. A strong lifting mechanism is required, and a strong driving force must be provided. When the above solder level control tank is attached to the lower part of a solder pool or a soldering nozzle that moves up and down, a gas such as gas or liquid having a specific gravity lighter than molten solder generates a larger buoyancy as it flows into the tank, Push up the solder pool etc. attached above. Here, the relationship between the solder level control and the buoyancy is compatible with each other. In other words, the more the solder pool and the like are exposed above the surrounding solder liquid level, the lower the solder bath solder liquid level and at the same time, the greater the load applied to the lifting mechanism such as the solder pool. Therefore, for example, by increasing the fluid pressure in the solder liquid level control tank according to the amount by which the solder liquid level of the solder tank falls, the solder is sent from the tank to the solder tank to maintain the liquid level. Simultaneously, the buoyancy generated by increasing the fluid volume in the tank is due to pushing up the solder pool and the like.

When the solder is heated and in a molten state, the surface that comes into contact with the outside air is rapidly oxidized and covered with a film. This oxide film hinders soldering. In other words, it adheres and accumulates on the surface of the vertically moving side wall of the solder pool or the like, and impairs its smooth movement. Therefore, maintenance such as continuous cleaning is required to maintain the performance of the mechanism. An antioxidant cover that covers a part of the solder surface, mainly a part that moves up and down, stops the progress of oxidation of the solder surface. At this time, if the shaft of the propeller that creates the jet is also sealed with packing, and the contact portion between the shaft and the solder surface is shielded from the outside air, it is possible to simultaneously suppress the oxidized powder of the solder that tends to be generated in the jet tank. This almost eliminates the need for the cleaning and the like for holding the mechanism, and eliminates wasteful consumption of solder discarded as sludge. Further, since the shape is simply fixed and sealed, there is no need for running costs unlike the case where an antioxidant or an inert gas is used.

The smaller the size of the soldering nozzle, the narrower the solder accommodating portion surrounded by the upper edge of the nozzle. Therefore, the leads of the components mounted on the substrate come into contact with the upper edge of the nozzle, and the adhesion between the substrate and the mounted components is easily damaged. Thus, by holding down the mounted components from above using a holding rod, the occurrence of floating components can be eliminated. Since a connector or the like mounted on a board is subjected to a large load when assembled into a device, the degree of close contact with the board is strictly required. In addition, the mounting height of the parts is limited when the light emitting device is incorporated in a light, thin and small case. The possibility of the occurrence of improper floating parts puts a great deal of man-hours on inspection and repair, and raises the production cost. These fears can be eliminated by the holding rod.

The above-mentioned holding rods are adjusted according to the height and shape of the mounted parts by means of level link bolts prepared for each rod, and the pressure is adjusted. Also, when the mounted component is pressed, the floating detection switch that detects the position of the holding rod confirms that the component and the board are in close contact, so that the mounted component can be soldered in the floating state. Can be prevented.

In this way, by using a fine soldering nozzle and using the above mechanism together, only the land, which is the soldering portion of the substrate, is brought into contact with the solder and heated. Point soldering is now possible.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a soldering nozzle.

FIG. 2 is a longitudinal sectional view showing an embodiment of a soldering nozzle.

FIG. 3 is a perspective view showing an embodiment of a soldering nozzle in a jet solder bath.

FIG. 4 is a perspective view showing an embodiment of a soldering nozzle in a jet solder bath.

FIG. 5 is a perspective view showing an embodiment of a soldering nozzle that moves up and down.

FIG. 6 is a perspective view showing an embodiment of a molten solder squeegee.

FIG. 7 is a perspective view showing an embodiment of a liquid level control tank.

FIG. 8 is a perspective view showing an embodiment of a liquid level control tank provided on the lower surface of the solder pool.

FIG. 9 is a perspective view showing an embodiment of an oxidation prevention cover.

FIG. 10 is a perspective view showing an embodiment of a holding rod.

FIG. 11 is a longitudinal sectional view showing an embodiment of a leveling bolt and a floating detection switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Solder tank 2 Land 3 Soldering nozzle 4 Solder hole 5 Inside of introduction pipe 7 Introduction pipe 8 Nozzle up-and-down mechanism 9 Melt solder squeegee 10 Liquid level control tank 11 Opening 12 Solder 13 Liquid level adjustment port 14 Solder pool 15 Solder surface 16 Outside air Reference Signs List 17 oxidation prevention cover 18 introduction port 19 air pressure valve 20 parts 21 holding rod 22 elastic body such as spring 23 leveling bolt 24 floating detection switch 25 substrate 26 jet nozzle 27 solder liquid level 28 plate surface 29 outer edge wall 30 minute solder surface 31 Storage recess

Claims (11)

[Claims] 1. A plurality of solders each having a top surface corresponding to a position of a plurality of lands (2) at a soldering position on a substrate and capable of simultaneously contacting the lands (2), and having an opening in the top surface. A partial soldering apparatus using a soldering nozzle (3) provided with holes (4), the openings of which have positions and shapes corresponding to the respective lands (2). 2. A solder hole (4) provided corresponding to each of a plurality of lands (2) is opened on a plate surface (28), a thickness of an opening thereof is reduced, and a position surrounding the solder hole (4). 2. A partial soldering apparatus according to claim 1, wherein an outer edge wall having a constant height is provided on the surface, or a soldering nozzle whose surface covers the surface of the solder container is used. 3. A soldering nozzle (3) provided with a solder hole (4) having an open lower end in the inlet pipe (5) in the partial soldering by the jet solder bath. Item 2. The partial soldering apparatus according to Item 2. 4. A soldering nozzle (3) provided with a solder hole (4) whose lower end is not opened in the inlet pipe (5) in the partial soldering by the jet solder bath. Item 2. The partial soldering apparatus according to Item 2. 5. A nozzle up / down mechanism (8) in which a soldering nozzle (6) and an introduction pipe (7) connected thereto are integrally moved up and down in partial soldering by a jet solder bath.
, A partial soldering device using a jet solder bath. 6. A partial soldering apparatus comprising a molten solder squeegee (9) that moves along the upper surface of a soldering nozzle (3). 7. Solder (12) housed in a solder bath (1)
A partial soldering apparatus in which an opening (11) is provided inside, and a liquid level control tank (10) having a liquid level adjusting port (13) through which gas or liquid flows in and out is provided in addition to a solder tank. 8. The partial soldering apparatus according to claim 7, wherein the liquid level control tank (10) is provided below the vertically moving solder pool (14) or below the vertically moving soldering nozzle (6). 9. A pressure valve (19) which covers a part of the solder surface (15) in the solder bath (1), blocks off the outside air (16), and keeps its internal pressure and external pressure constantly constant. A partial soldering device provided with an oxidation prevention cover (17). 10. A partial soldering device comprising a holding rod (21) for pressing a mounting component (20) in a direction in which the mounting component (20) is brought into close contact with a substrate by an elastic body (22) such as a spring. 11. A leveling bolt (23) for adjusting the pressure of the holding rod (21), and a floating detection switch (24) for detecting the position of the holding rod (21) is provided in accordance with the holding rod (21). The partial soldering device according to claim 10.