JPS595393B2 - Brazing material receiving mechanism of brazing equipment - Google Patents

Description

[Detailed description of the invention] .

[Technical field of the present invention] The present invention is an apparatus for brazing the back side of a printed circuit board by spouting a brazing material such as molten solder, which receives the spouted brazing material and stabilizes the brazing material in a brazing material storage tank. The present invention relates to a brazing material receiving mechanism that can be returned to the original state.

[Technical background of Ming.] Generally, an apparatus as shown in FIGS. 1 and 2 is used to braze lead wires of electrical components mounted on a printed circuit board to a circuit pattern.

That is, 1 is a brazing material storage tank in which a brazing material 2 such as molten solder is stored. The molten brazing filler metal 2 in the brazing filler metal storage tank 1 is pumped by an electromagnetic pump 3 and is ejected from a slit-shaped nozzle 4 in the form of a thin film. Then, the printed circuit board 5 to be brazed is transported so that its back surface is in contact with the spouting brazing material 2, and the lead wires and circuit patterns protruding from the back surface of the printed circuit board 5 are brazed by the spouting brazing material 2. is configured to be The electromagnetic pump 3 is constructed as follows.

6 is a flow path through which the molten brazing filler metal 2 flows.

Further, 1 is an iron core, and a coil 8 is wound around this iron core 1. Then, a part of this iron core 1 was cut out,
The channel 6 is inserted through this notched portion, and the structure is such that a magnetic field in a direction perpendicular to the axial direction of the channel 6 is applied to the brazing material in the channel 6. Further, a pair of electrodes 9, 9 are attached to both sides of the flow path 6, and a current is configured to flow between the electrodes 9, 9 in a direction perpendicular to the axial direction of the flow path 6 and the direction of the magnetic field. has been done. Therefore, the brazing material in the flow path 6 is forced in the axial direction of the flow path 6 by the magnetic field and current in directions perpendicular to each other, and is ejected from the nozzle 4.
However, in such a device, a large current flows through the contact surface between the electrodes 9, 9 and the flow path 6, so the wall of the flow path 6 is likely to corrode at the contact area with the electrodes 9, 9, resulting in poor reliability. It was hot.

Furthermore, since the brazing filler metal flows from the brazing filler metal storage tank 1 through the channel 6, there is a problem that the temperature tends to drop.

Further, when the operation of such a brazing apparatus is stopped and the operation is started after the brazing material has solidified, the brazing material must first be heated and melted.

In this case, if the brazing material in the channel 6 is melted first, the thermal expansion of the brazing material in the channel 6 will not escape, and the internal pressure of the channel 6 will become extremely high, causing damage to the channel 6. For this reason, in the conventional method, the brazing material in the brazing material storage tank 1 is heated and melted using a heater or the like, and after all of the brazing material in the brazing material storage tank 1 is melted, it is heated and melted by a heater or the like provided outside the channel 6. The brazing filler metal in channel 6 was being heated and melted. As a result, there were problems such as a long time required to start operation. In order to eliminate such problems, a brazing material pressure flow path is formed within the brazing material storage tank, and a coil mechanism is provided outside the brazing material storage tank corresponding to this brazing material pressure flow path. A system has been developed in which a moving magnetic field is formed in the brazing material pressure passage, and the moving magnetic field forces the brazing material within the brazing material pressure passage and ejects it from a nozzle.

This product does not require contact parts such as electrodes to pass current through the brazing material, is highly reliable, and has a brazing material pressure flow path in the brazing material storage tank, making it easy to keep the brazing material warm and heated. It has advantages such as being easy. [Problems with the Background Art] By the way, in the above-mentioned device in which the brazing material is pumped using a moving magnetic field, if the shape of the brazing material pumping channel becomes complicated, the structure of the coil mechanism becomes correspondingly extremely complicated.

Therefore, in practice, the shape of the brazing material pressure passage must be relatively simple, such as a straight line. A simple shape of the brazing material pressure flow path has the advantage of reducing flow path resistance, but on the other hand, the pressure fluctuations of the supplied molten brazing material directly act on the nozzle, and from this nozzle. There is a characteristic that the ejection speed of the brazing filler metal tends to fluctuate.
For this reason, if the brazing filler metal ejected from the nozzle falls into the brazing filler metal storage tank and the liquid level of the brazing filler metal ripples, the pressure fluctuations caused by the ripples will cause the ejection speed of the brazing filler metal to fluctuate. occurs. In addition, the length of the brazing material pressure flow path is required to be a certain length in order to obtain a predetermined pressure, but if the shape of the brazing material pressure flow path is simple, such as a straight line as described above, this is not possible. In response to this, the brazing filler metal storage tank had to be enlarged. For this reason, the liquid surface area of the molten brazing material stored in the brazing material storage tank becomes large, which also causes problems such as oxidation and other deterioration of the brazing material. [Object of the Invention] The present invention has been made based on the above circumstances, and its purpose is to stabilize the ejection of the brazing material and to improve the quality of the brazing material in a device that pumps the brazing material using a moving magnetic field. It is an object of the present invention to provide a brazing material receiving mechanism for a brazing device that can effectively prevent oxidation and the like.

[Summary of C Ming] That is, the present invention includes a brazing filler metal pressure flow path provided inside a brazing filler metal reservoir for storing molten brazing filler metal, and a brazing filler metal pressure flow channel provided outside the brazing filler metal reservoir corresponding to this brazing filler metal pressure flow channel. In the brazing apparatus described above, the brazing apparatus is provided with a coil mechanism that generates a moving magnetic field in the brazing material pressure-feeding channel to force-feed the brazing material in the brazing-metal pressure-feeding channel, and a nozzle that spouts out the pressure-fed brazing material. a lid body that closes the top opening of the brazing material storage tank;
A brazing material receiving recess is provided on the lid body corresponding to the falling position of the molten brazing material ejected from the nozzle to receive and collect the falling molten brazing material, and the brazing material is stored from the bottom of the brazing material receiving recess. It is provided with a flowing down nozzle that protrudes into the tank and whose lower end is immersed in the molten brazing material stored in the brazing material storage tank.

Therefore, the brazing filler metal ejected from the nozzle falls into the brazing filler metal receiving recess, and is returned from the brazing filler metal receiving recess into the brazing filler metal storage tank via the downstream nozzle. Since the lower end of this flow nozzle is immersed below the liquid level of the brazing filler metal in the brazing filler metal reservoir, the liquid surface of the brazing filler metal will not ripple when the brazing filler metal is returned to the brazing filler metal reservoir. There is no problem, and the brazing filler metal jets out stably. Further, since the lower end of the flowing nozzle is immersed in the brazing material, the lid body is cut off from the outside air, preventing oxidation of the brazing material, and reducing deterioration of the brazing material.
Embodiment of the present invention] An embodiment of the present invention will be described with reference to FIGS. 3 to 7.

In the figure, 101 is a brazing material storage tank that stores a brazing material 102 such as molten solder.

This brazing filler metal storage tank 101 has a wide part 10 with a wide end.
1a, and the other end is a narrow part 101b with a narrow width.
, and has a substantially T-shaped planar shape. The brazing filler metal storage tank 101 is composed of a thick bottom plate 103 and a side plate 104, and a heat insulating material 105 is provided on the outer surface of the side plate 104 to keep the brazing filler metal 102 stored inside warm. It is configured. And the above bottom plate 1
03 is formed with a channel forming portion 106 cut out in an elongated shape extending from the narrow portion 101b to the wide portion 101a. Steps are formed on the inner and outer surfaces of both side edges of the flow path forming portion 106. A thin outer bottom wall plate 107 is fitted into the stepped portion on the outer surface, and an inner bottom wall plate 108 is fitted into the stepped portion on the inner surface.
09... are integrally attached to the bottom plate 103. The outer bottom wall plate 107 and the inner bottom wall plate 10
8 is formed as a brazing material pressure feeding channel 110. One end of this brazing material pressure-feeding channel 110 is connected to a narrow portion 101.
It communicates with the brazing material reservoir 101 at the tip of b. Further, a nozzle 111 is provided upright at the end of the wide portion 101a of the brazing material storage tank 101. This nozzle 1
11 is an elongated part extending over the entire width of the wide part 101a, and a slit-shaped nozzle hole 112 is provided at the upper end of the wide part 101a over almost the entire width, and this nozzle hole 112 is oriented obliquely upward. The other end of the brazing material pressure passage 110 communicates with the inside of this nozzle 111. A thin heat insulating material 113 is attached to the lower surfaces of the bottom plate 103 and the outer bottom wall plate 107. A coil mechanism 114 is provided on the outer side, that is, on the lower surface, of the outer bottom wall plate 107 in correspondence with the brazing material pressure passage 110 .
Reference numeral 115 is the stator core, which is formed into a block shape by laminating thin steel plates.

The width of this stator core 115 is the width of the brazing material pressure passage 1
10, and its length is approximately equal to the width of the brazing material pressure channel 1.
10, and its upper surface is in contact with the outer bottom wall plate 107 via the above-mentioned heat insulating material 113. A plurality of coil accommodating grooves 116 are formed on the upper surface of the stator core 115 along a direction perpendicular to the axial direction of the brazing material pumping path 110. The plurality of coil housing grooves 116 are arranged at predetermined intervals along the axial direction of the brazing material pumping path 110. and,
Stator coils 117 are housed in these coil housing grooves 116, respectively. These stator coils 117 have a substantially oval shape and are inserted into the coil housing grooves 116. The height of these stator coils 117... is determined by the height of the coil accommodation groove 116.
...thus, these stator coils 1
A cooling gap 118 is formed between the outer bottom wall plate 107 and the outer bottom wall plate 107 . Further, an elongated iron core 119 is provided on the inner side, that is, on the upper surface of the inner bottom wall plate 108. Then, the stator coil 117...
is configured such that alternating currents with phase shifts are sequentially supplied from the narrow portion 101b side to the wide portion 101a side. Therefore, these stator coils 117 pass through the stator core 115 and the core 119, and cross the brazing material pressure passage 110.
... are formed, and these magnetic fields move from the narrow portion 101b toward the wide portion 101a. Therefore, the moving magnetic field forces the brazing material in the brazing material feeding channel 110 toward the wide portion 101a, increases the pressure to a predetermined pressure, and supplies the brazing material into the nozzle 111. Further, a cooling fan 121 is provided on the side of the base 120 that supports the brazing material storage tank 101.
The cooling fan 121 is configured to send cooling air to the coil mechanism 114. Then, this cooling air is guided by the air guide plates 122, 122, and the stator coil 1
17... and the gap 118... between the outer bottom wall plate 107
The stator coils 117 are cooled by the heat transmitted from the molten brazing filler metal 102 in the brazing filler metal reservoir 101 and the heat generated by these stator coils 117 themselves. ...is constructed to prevent it from overheating. In addition, stator coil 117...
- Temperature detectors 123, 123 are provided inside, and are configured to monitor the temperature rise of these stator coils 117... The brazing material 102 supplied into the nozzle 111 is configured to be ejected in a thin film form from a slit-shaped nozzle hole 112.

A pressure regulator 124 in the form of an elongated plate is provided within the nozzle 111. This flow rate adjusting body 124 has a plurality of orifice holes 12 along the width direction as shown in FIG.
5... are formed, and these orifice holes 125...
The aperture is small in the center and becomes larger toward the outside. Therefore, the brazing material supplied to the center of the nozzle 111 from the brazing material pressure feeding channel 110 passes through this pressure regulator 124, so that the pressure becomes uniform across the width, and the pressure is uniform across the width from the nozzle hole 112. It is configured to eject uniformly in all directions. Further, a lid 126 is attached to the brazing filler metal storage tank 101 to cover it.

A brazing material receiving recess 127 is formed in the lid 126, and the brazing material ejected from the nozzle 111 is configured to fall into the brazing material receiving recess 127. In this brazing metal receiving recess 121, there is a downstream nozzle 12.
8,128 are formed, and these downstream nozzles 128,12
The lower end of 8 is immersed in brazing material 102 in brazing material storage tank 101 . The brazing filler metal that has fallen into the brazing filler metal receiving recess 127 is configured to flow into the brazing filler metal storage tank 101 through the downstream nozzles 128 , 128 , and the spouted brazing filler metal flows into the brazing filler metal 102 in the brazing filler metal storage tank 101 . It is configured to prevent the brazing filler metal from falling directly onto the liquid surface, to prevent pressure fluctuations in the brazing filler metal storage tank 101 due to vibrations of the liquid level, and to stabilize jetting of the brazing filler metal from the nozzle 111. Further, a cover gas such as nitrogen is supplied from a cover gas supply mechanism 129 to the space inside the brazing material storage tank 101.
It is configured to prevent oxidation etc. on the surface of 02.
Rod-shaped heaters 130 are provided in the wide portion 101a and the narrow portion 101b of the brazing filler metal storage tank 101, and these heaters 130 cause the wax in the brazing filler metal storage tank 101 to It is configured to heat and melt the material 102 or maintain it at a predetermined temperature.

Moreover, rod-shaped heaters 131, 131 are embedded in the bottom plate 103 along both sides of the brazing material pressure passage 110,
By these heaters 131, 131, the brazing material pressure passage 1
10 is configured to be able to heat the brazing filler metal. Furthermore, the narrow portion 101b of the brazing material storage tank 101
A dam plate 132 having an L-shaped cross section is provided across the inside, and a slight gap is formed between the lower edge of this dam plate 132 and the bottom plate 103, and the brazing material 102 passes through this gap. It is structured to flow.

Therefore, foreign matter mixed into the brazing filler metal 102 is collected by the dam plate 132 to prevent the nozzle 111 from clogging. The operation of one embodiment of the present invention will be explained below.

The stator coils 117 are supplied with alternating currents that are out of phase with each other.

Therefore, each stator coil 117 passes through the stator core 115 and the core 119, and the brazing material pressure passage 1
A magnetic field is created that crosses the wide portion 10
Move in the direction toward 1a. Therefore, the moving magnetic field forces the brazing material in the brazing material feeding channel 110, increases the pressure to a predetermined pressure, and supplies the brazing material to the nozzle 111. The brazing material supplied into the nozzle 111 is ejected from the nozzle hole 112 in the form of a thin film, and is ejected from the brazing material receiving recess 127 of the lid 126.
The brazing material is returned to the brazing material storage tank 101 through the downstream nozzles 128, 128. Then, the printed circuit board 133 to be brazed is transported horizontally so that its back surface is in contact with the spouting brazing material, and the lead wires and circuit patterns protruding from the back surface of the printed circuit board 133 are brazed. In addition, when the operation of this apparatus is stopped and the operation of the apparatus is started from a state where the brazing filler metal has solidified, the brazing filler metal storage tank 101
The heater 130 inside is energized and the brazing material storage tank 1 is
The brazing filler metal 102 in 01 is heated and melted.

In this case, the heat of the brazing filler metal 102 in the brazing filler metal storage tank 101 is efficiently transferred to the brazing filler metal in the brazing filler metal pressure passage 110 via the inner bottom wall plate 108.
When the brazing filler metal 102 inside is melted, the brazing filler metal pressure passage 1
The brazing filler metal in 10 is on the verge of melting. Therefore,
After the brazing filler metal 102 in the brazing filler metal storage tank 101 is melted, the heaters 131, 131 embedded in the bottom plate 103 are energized to heat the brazing filler metal in the brazing filler metal pressure channel 110. The filler metal inside will melt immediately. Therefore, the time required to start operation is shortened. Also,
In this tank, the bottom wall of the brazing material storage tank is made up of an outer bottom wall plate 107 and an inner bottom wall plate 108, and a brazing material pressure passage 110 is formed between the two. The structure is simple since it only includes the coil mechanism 114, and there is no need to run a large current through the brazing material pressure passage 110, so there is no fear of corrosion, and the reliability is high.

Furthermore, this thing has an iron core 119 inside the inner bottom wall plate 108.
Since a magnetic circuit is formed through the iron core 119 and the stator iron core 119, the brazing material pressure passage 110 is the only magnetic gap in this magnetic circuit, so that efficiency is improved.

Note that the present invention is not limited to the above embodiment.

For example, the brazing material pressure passage does not necessarily need to be formed on the bottom wall of the brazing material storage tank, but may be provided on the side wall or other locations.

Furthermore, it is not necessary to provide an iron core inside the inner wall that constitutes the brazing material pressure passage.

[Effects of the Invention] As described above, the present invention includes a brazing material pressure flow path provided inside a brazing material storage tank for storing molten brazing material, and a brazing material pressure flow path provided in the brazing material storage tank corresponding to this brazing material pressure flow path. A brazing device comprising: a coil mechanism provided on the outside that generates a moving magnetic field in the brazing material pressurizing flow path to forcefully feed the brazing filler metal in the brazing metal pressurizing flow path; and a nozzle that spouts the pressurized brazing filler metal. , a lid for closing the upper opening of the brazing filler metal storage tank, and a brazing filler metal provided on the cover corresponding to the falling position of the molten brazing filler metal ejected from the nozzle to receive and collect the falling molten brazing filler metal. The brazing material receiving recess includes a flowing down nozzle that protrudes from the bottom of the brazing material receiving recess into the brazing material storage tank and has a lower end immersed in the molten brazing material stored in the brazing material storage tank. .

Therefore, the brazing filler metal ejected from the nozzle falls into the brazing filler metal receiving recess, and is returned from the brazing filler metal receiving recess into the brazing filler metal storage tank via the downstream nozzle. Since the lower end of this flow nozzle is immersed below the liquid level of the brazing filler metal in the brazing filler metal reservoir, the liquid surface of the brazing filler metal will not ripple when the brazing filler metal is returned to the brazing filler metal reservoir. There is no problem, and the brazing filler metal jets out stably. In addition, since the lower end of this flowing nozzle is immersed in the brazing material, the lid body is shut off from the outside air, preventing oxidation of the brazing material, and reducing deterioration of the brazing material.

[Brief explanation of drawings]

1 and 2 show a conventional example, with FIG. 1 being a schematic configuration diagram and FIG. 2 being a perspective view of an electromagnetic pump. 3 to 7 show one embodiment of the present invention, in which FIG. 3 is a longitudinal sectional view, FIG. 4 is a plan view, and FIG. 5 is a V-V of FIG. 4.
6 is a perspective view of the coil mechanism, and FIG. 7 is a view taken along the - arrow in FIG. 3. 101... Brazing metal storage tank, 101a... Wide part, 101b... Narrow part, 10
2... Brazing metal, 103... Bottom plate, 107... Outer bottom wall plate, 108... Inner bottom wall plate, 110... Brazing metal pressure flow channel, 111... Nozzle, 114... - Coil mechanism, 115... Stator core, 11゛6... Coil accommodation groove, 117... Stator coil, 118... Gap,
121... Cooling fan, 126... Lid body, 127.
... Brazing metal receiving recess, 128... Downflow nozzle.

Claims (1)

[Claims] 1. A brazing material pressure flow path provided inside a brazing material storage tank for storing molten brazing material, and a brazing material pressure flow path provided outside of the brazing material storage tank corresponding to this brazing material pressure flow path. In a brazing apparatus equipped with a coil mechanism that generates a moving magnetic field within the brazing material reservoir to forcefully feed the brazing material in the brazing material pressure flow path, and a nozzle that spouts out the forced brazing material, the brazing material storage tank has an upper opening. A lid body that closes, a brazing metal receiving recess provided in the lid body corresponding to a falling position of the molten brazing material ejected from the nozzle to receive and collect the falling molten brazing material, and a brazing metal receiving recess for receiving and collecting the falling molten brazing material. A brazing material receiving mechanism of a brazing apparatus, characterized in that the brazing material receiving mechanism of a brazing apparatus is provided with a flowing down nozzle that protrudes from the bottom into the brazing material storage tank and has a lower end immersed in the molten brazing material stored in the brazing material storage tank. .