JP7065478B2 - Metal sheet metal joining device - Google Patents

Description

The present invention relates to a metal thin plate joining apparatus, and more particularly to a technique for diffusing and joining a plurality of thin SUS plates and the like.

Currently, diffusion bonding (thermocompression bonding) technology has been put into practical use as one of the methods for joining thin metal plates (metal foils) such as SUS.
In this method, the metal plates are heated to a predetermined temperature in a vacuum, the joint surface is pressurized, and when the metal plates are held for a while, the metal plates are joined by the diffusion phenomenon of the metal, without relying on inclusions such as adhesives. , A technique capable of reliably joining joint surfaces (see Non-Patent Document 1).
In order to realize this diffusion bonding, it goes without saying that the cleanliness and flatness of the bonded surface are required, but the heat equalization property on the bonded surface is also indispensable.

FIG. 11 is a schematic diagram for explaining the principle of conventional diffusion bonding, in which a bonding object 20 in which a plurality of thin metal plates made of SUS material or the like are laminated in a vacuum chamber 80 is placed on a press rod 12 and an upper side. It is depicted that the pressure plate 82 is placed between the base rod 18 and the lower push plate 82 to pressurize.
Each push plate 82 is made of a heat-resistant material.
Each metal thin plate, which is the object to be joined 20, is heated to about 800 ° C. by the radiant heat of the infrared heater 84.

What is diffusion bonding (thermocompression bonding)? Internet URL: http://www.yama-tech.com/kakusan/ Search date: October 17, 2017

As described above, since the conventional method is to indirectly heat a plurality of thin metal plates by the radiant heat from the infrared heater 84, the parts other than the object to be joined 20 (press rod 12, upper push plate 82, base rod 18, There is a problem that heat is also transferred to the lower push plate 82), and it takes time for the bonding object 20 to reach the diffusion bonding temperature.
Further, if the thin metal plate is taken out at a high temperature, the contour portion is oxidized, so that it is necessary to cool it to 250 ° C. or lower, but this cooling also takes a long time.

For example, under predetermined conditions, it takes about 30 minutes for a plurality of SUS thin plates having a thickness of 100 μm to reach a diffusion bonding temperature of about 800 ° C., and about 15 minutes as a time required for pressure bonding, for taking out from the vacuum. It takes about 60 minutes for the cooling time, and about 105 minutes in total.

The present invention has been devised to solve the problems of the prior art, and an object of the present invention is to provide a technique capable of shortening the time required for diffusion bonding by reducing the heat capacity of the object to be heated as much as possible. It is supposed to be.

In order to achieve the above object, the metal thin plate joining apparatus according to claim 1 has a processing table on which a joining object in which a plurality of metal thin plates are laminated is placed, and a pressure applied to the joining target. It is interposed between the member, a pair of heating plates that are in contact with one surface and the opposite surface of the object to be processed, between one heating plate and the processing table, and between the other heating plate and the pressurizing member. A pair of heat insulating materials, a vacuum chamber for accommodating the processing table, the pressurizing member, the heating plate and the heat insulating material, an induction heating coil arranged outside the vacuum chamber, and a high-frequency current being supplied to the coils. Each of the above heating plates is characterized by being composed of a metal material capable of induction heating.

Further, the metal thin plate joining device according to claim 2 is the device according to claim 1, and further, by forming a slit in the heating plate, the heating plate is divided into a plurality of heat generating cells. It is a feature.

The metal thin plate joining device according to claim 3 is the device according to claim 1 or 2, further, a temperature sensor for measuring the surface temperature of the heating plate, and the surface temperature of the heating plate output from the temperature sensor. It is characterized by having a control means for turning off the power supply to the coil when the value of exceeds a predetermined upper limit value and turning on the power supply to the coil when the value falls below a predetermined lower limit value. It is supposed to be.

The metal thin plate joining device according to claim 4 is the device according to claim 1 or 2, further, a temperature sensor for measuring the surface temperature of the heating plate, and the surface temperature of the heating plate output from the temperature sensor. It is provided with a control means for reducing the amount of power supplied to the coil when the value of exceeds a predetermined upper limit value and increasing the amount of power supplied to the coil when the value falls below a predetermined lower limit value. It is characterized by.

The metal thin plate joining device according to claim 5 is the device according to claims 1 to 4, further, from an insulating material having relatively excellent thermal conductivity between each of the above heating plates and the object to be joined. It is characterized by interposing a fusion prevention plate.

The metal thin plate joining device according to claim 6 is the device according to claims 1 to 5, further comprising a mechanism for reciprocating the coil up and down in a predetermined cycle.

The metal thin plate joining device according to claim 1 is a method of heating an object to be joined by a heating plate based on the principle of high frequency induction heating, and also has a processing table and a pressurizing means. Since the heat insulating material is arranged between them, the heating target can be narrowed down to the joining target.
As a result, it becomes possible to perform diffusion bonding between a plurality of metal thin plates in an extremely short time.

In the metal thin plate joining device according to claim 2, since each heating plate is divided into a plurality of heat generating cells by forming slits, heat generation unevenness due to the skin effect is eliminated, and the entire surface of each metal thin plate is evenly covered. It becomes possible to join.
In addition, by preparing multiple heating plates with different slit formation patterns and replacing the heating plates appropriately according to the workpiece to be joined, it is possible to easily realize a temperature distribution pattern optimized for the workpiece. It becomes.

In the case of the metal thin plate joining apparatus according to claims 3 and 4, since the amount of electric power supplied to the coil is controlled according to the temperature change of the heating plate, the temperature of the heating plate is stabilized to the optimum level for diffusion joining. It is possible to make it.

In the case of the metal thin plate joining apparatus according to claim 5, a fusion prevention plate made of an insulating material having relatively excellent thermal conductivity is interposed between the heating plate and the object to be joined, so that the heating plate is used. It is possible to make the heat uniform and transfer it to the object to be joined, and even joining is realized.

According to the metal thin plate joining device according to claim 6, by reciprocating the coil up and down, it is possible to generate heat evenly in each heating plate, and by extension, it is possible to diffusely join the metal thin plates evenly. ..

FIG. 1 is a schematic view illustrating the basic structure of the first diffusion joining device 10 according to the present invention, which is attached to a press rod 12 arranged in a glass vacuum chamber 11 and a lower end of the press rod 12. The heat insulating material 14, the heating plate 16 arranged on the lower surface of the heat insulating material 14, the base rod 18, the heat insulating material 14 attached to the upper end of the base rod 18, and the heating plate arranged on the upper surface of the heat insulating material 14. It has 16 and.
Further, between the upper heating plate 16 and the lower heating plate 16, a joining object 20 in which a plurality of thin metal plates made of SUS material or the like having a thickness of about 100 μm are laminated is arranged.
The heat insulating material 14 is made of an insulating material having a relatively low thermal conductivity.
The heating plate 16 is made of a metal material such as iron or stainless steel that can be a heated body by high frequency induction heating, and its thickness is set to about 1 mm.

A circular coil 22 for high frequency induction heating (IH) and a ceramic cylindrical cover 24 are arranged around the object to be joined 20 outside the vacuum chamber 11.
The circular coil 22 is fixed to the outer peripheral surface of the cylindrical cover 24.

Here, when a switch of a high-frequency power supply (not shown) is turned on and a high-frequency current (for example, 400 KHz) is passed through the circular coil 22, eddy currents are generated inside the upper heating plate 16 and the lower heating plate 16 as a result. , Both heating plates 16 generate heat and heat the object to be joined 20.
At the same time, the contact surface between the metal thin plates is thermocompression-bonded by pressurizing the object 20 to be joined with the press rod 12 for a predetermined time and at a predetermined pressure.

In this way, the upper heating plate 16 in contact with the object to be joined 20 and the lower heating plate 16 itself serve as heat sources, and the heat insulating material 14 is arranged between the press rod 12 and the base rod 18. The heating target is almost limited to the bonding target 20, and the heating efficiency can be dramatically improved.

FIG. 2 is a plan photograph taken from above with the press rod 12 removed in order to show the state of the heating plate 16 at the time of high frequency induction heating. 30 is occurring (actually it glows orange).
As described above, only the peripheral portion of the upper heating plate 16 is heated to a high temperature, and the central portion thereof is left at a relatively low temperature due to the skin effect of the alternating current and the proximity effect of the coil.

As a result, as a matter of course, each metal thin plate in the object to be joined 20 is also diffusion-bonded according to the shape pattern of the high-temperature tropical 30 and the central portion of each is left unbonded.
Depending on the purpose of diffusion bonding, it may be sufficient to join only the peripheral portion of each metal sheet in a square frame shape as described above.

On the other hand, in order to diffusely join the entire contact surface of the thin metal plate, the shape of the heating plate 16 can be devised.
For example, as shown in FIG. 3, it corresponds to subdividing the heat generating region into a plurality of cells by forming a plurality of slits 32 penetrating from the front surface to the back surface in each of the upper and lower heating plates 16.

Here, two relatively long vertical slits 32a and 32c are formed on the upper side of the heating plate 16 at predetermined intervals toward the lower side, and one relatively short slit 32b is formed in the middle of the two. ..
Further, on the lower side of the heating plate 16, two relatively short vertical slits 32d and 32f are formed at predetermined intervals toward the upper side, and one relatively long slit 32e is formed in the middle of the two. There is.
Further, on the left side of the heating plate 16, four relatively short horizontal slits 32g to 32j are formed at predetermined intervals toward the right side.
Similarly, on the right side of the heating plate 16, four relatively short lateral slits 32k to 32n are formed at predetermined intervals toward the left side.

As a result of the above, the heating plate 16 is divided into heat generating cells 34A to 34R surrounded by a broken line.
If the area of each heat generating cell 34 is small, the amount of magnetic flux picked up is small, and heat generation is reduced. On the contrary, if it is large, the calorific value increases, but the temperature unevenness increases due to the skin effect.
Therefore, the size of each heat generating cell is adjusted in consideration of the magnetic flux density of the circular coil 22.

For example, since the four corners of the heating plate 16 are close to the circular coil 22, one side is set relatively short as in the heating cells 34D, 34E, 34Q, 34R.
On the other hand, since the number of magnetic fluxes is small in the central portion of the heating plate 16, one side of the heat generating cells 34G and 34K is set relatively long.

FIG. 4 is a plan photograph in which a heating plate 16 having a slit 32 formed is arranged instead of the flat plate-shaped heating plate 16 shown in FIG. 2 to perform high-frequency induction heating, and heat is generated over almost the entire surface. You can see how it is doing (actually, the whole glows orange).
This is because the current passages are dispersed by the plurality of slits 32, and the heating plate 16 is divided into a plurality of heat generating cells.

When supplying high-frequency power to the circular coil 22, the temperature of both heating plates 16 is monitored by a temperature sensor (not shown), the power is turned off when the predetermined upper limit temperature is reached, and the predetermined lower limit temperature is reached. By providing a control device having a function of turning on the power when the temperature reaches the limit, the temperature of the heating plate 16 can be stabilized to a required level.

FIG. 5 is a graph showing the temperature of the heating plate 16 on the vertical axis and the elapsed time on the horizontal axis, and the portion surrounded by a circle in the figure corresponds to the period in which the power is turned on / off.
In this way, by providing a plurality of ON / OFF switching periods in the pressurizing / joining section, it is possible to stabilize the temperature of the heating plate 16 to the optimum level for diffusion joining.
It is also possible to realize constant temperature of the heating plate 16 by controlling the output of the power supply according to the temperature of the heating plate 16 instead of repeatedly turning the power on and off.

FIG. 6 shows the correspondence between the passage of the heating time and the heat generation state of the heating plate 16, and the heating plate 16 is shown in the figure (a) 3 seconds after the power switch is turned on and heating is started. It becomes the state of. As shown in the figure, at this stage, only the peripheral edge of the upper heating plate and the narrow region along the slit become hot, and the temperature distribution is uneven.
The figure (b) shows the state 5 seconds after the start of heating, and although almost the entire area of the heating plate generates heat, the temperature distribution still shows some unevenness.
On the other hand, the figure (c) shows the state immediately after 8 seconds have passed from the start of heating and the power switch is turned off. It can be seen that it has not occurred.
The ON / OFF switching control of the power switch is executed between (b) and (c) in the figure.

FIG. 7 shows a second diffusion joining device 40 according to the present invention, between the upper heating plate 16 and the joining object 20, and between the lower heating plate 16 and the joining object 20. In addition, it is characterized in that a fusion prevention plate (separation plate) 42 made of an insulating material having excellent thermal conductivity is interposed.
As the fusion prevention plate 42, for example, an aluminum nitride plate, a silicon carbide plate, a graphite plate, an amorphous carbon plate, or the like is used.

By arranging the fusion prevention plate 42 between the heating plate 16 and the object to be bonded 20 in this way, there is an advantage that the object to be bonded 20 can be easily taken out after diffusion bonding.

Further, as shown in FIG. 8A, even if the heating plate 16 having the slit 32 formed is subjected to high frequency induction heating, the formed portion of the slit 32 does not naturally generate heat, and each heat generated separated by the slit 32 is generated. Even if the cells have the same area, the amount of heat generated differs depending on the magnetic flux distribution. Even within the same heat-generating cell, the skin effect causes slight temperature unevenness.
On the other hand, when the fusion prevention plate 42 made of an insulating material having excellent thermal conductivity is arranged on the surface of the heating plate 16, the fusion prevention plate 42 has the slit 32 formed as shown in FIG. 8 (b). The whole body including the above is heated to a high temperature evenly, and as a result, the object 20 to be bonded can be heated evenly.

In FIG. 8B, a small fusion prevention plate 42 is intentionally used to show the existence of the slit 32 formed in the heating plate 16, but the area is actually about the same as that of the heating plate 16. The provided fusion prevention plate 42 is used.

FIG. 9 shows a third diffusion joining device 50 according to the present invention, in which an upper heat insulating material 14, an upper heating plate 16, and a first fusion prevention are shown between the press rod 12 and the base rod 18. Plate 42a, 1st bonding object 20a, 2nd fusion prevention plate 42b, 2nd bonding object 20b, 3rd fusion prevention plate 42c, 3rd bonding object 20c, 4th fusion A prevention plate 42d, a lower heating plate 16, and a lower heat insulating material 14 are interposed.
That is, the third diffusion joining device 50 can diffusely join the three joining objects 20a to 20c separated by the four fusion prevention plates 42a to 42d.
By increasing the number of welding prevention plates 42, it is possible to perform diffusion bonding of a larger number of bonding objects 20 at one time.

In this case, it is desirable to connect the movable portion 54 of the vertical movement mechanism 52 to the cylindrical cover 24 as shown in the figure.
The movable portion 54 can reciprocate the circular coil 22 up and down at a predetermined speed by the action of the motor in the vertical movement mechanism 52, and when the circular coil 22 reaches the uppermost position, the upper heating plate 16 When it reaches the lowest position, it comes closest to the lower heating plate 16.
As a result, it is possible to make the heat generation in the upper heating plate 16 and the lower heating plate 16 uniform.

By devising the formation pattern (number of formations, dimensions, positions, angles, etc.) of the slit 32 provided in the heating plate 16, it is possible to adjust the joining pattern between the metal thin plates to an arbitrary shape.

For example, as shown in FIG. 10A, slits 32 having a length of about one-third of one side are formed in the central portions of the upper side, the lower side, the left side, and the right side of the heating plate 16, and are divided into four heat generating cells. If this is the case, high-temperature tropical 30 will occur at the periphery of each heat-generating cell during heat generation.
Therefore, when diffusion bonding is performed using the heating plate 16 of this slit pattern, the metal thin plates are bonded along the high temperature tropical 30 and the central portion of each heat generating cell and the central portion of the heating plate 16 are connected. An almost "X" -shaped unjoined portion can be obtained.

Alternatively, as shown in FIG. 10B, even when a slit 32 that divides the four corners of the heating plate 16 into two equal parts is added and divided into eight heat generating cells, high temperature is generated at the peripheral portion of each heat generating cell during heat generation. Tropical 30 occurs.
Therefore, when diffusion bonding is performed using the heating plate 16 of this slit pattern, the metal thin plates are bonded along the high temperature tropical 30 and the central portion of each heat generating cell and the central portion of the heating plate 16 are connected. It is possible to obtain an unjoined part in the shape of a "well".

In the above, an example has been described in which the joining object 20 is placed on the base rod 18 as a "processing table" and the joining object 20 is pressurized by the press rod 12 as a "pressurizing member". , The pressure may be applied to the object to be joined 20 from the base rod 18 side as well.

It is a schematic diagram explaining the basic structure of the 1st diffusion joining apparatus which concerns on this invention. It is a plane photograph which shows the state of a heating plate at the time of high frequency induction heating. It is a top view which shows the appearance that a plurality of slits were formed in a heating plate. It is a plane photograph when high frequency induction heating was performed using the heating plate which formed a plurality of slits. The vertical axis is the temperature of the heating plate, and the horizontal axis is the elapsed time. It is a photograph showing the correspondence relationship between the passage of heating time and the heat generation state of a heating plate. It is a schematic diagram explaining the basic structure of the 2nd diffusion joining apparatus which concerns on this invention. It is a photograph showing the comparison of the heat generation state with and without the fusion prevention plate having excellent thermal conductivity. It is a schematic diagram explaining the basic structure of the 3rd diffusion joining apparatus which concerns on this invention. It is a photograph showing the correspondence between the pattern of the slit formed in the heating plate and the heat generation pattern. It is a schematic diagram which shows the basic structure of the conventional diffusion joining apparatus.

10 First diffusion joining device
11 Vacuum tank
12 press rod
14 Insulation
16 heating plate
18 Base rod
20 Object to be joined
22 Circular coil
24 Cylindrical cover
30 High temperature tropical
32 slit
34 Fever cell
40 Second diffusion joining device
42 Anti-fusing plate
50 Third diffusion joining device
52 Vertical movement mechanism
54 Moving parts

Claims (6)

A processing table on which an object to be joined, which is a stack of multiple thin metal plates, is placed.
A pressurizing member that applies pressure to the object to be joined,
A pair of heating plates that come into contact with one side and the other side of the object to be processed,
A pair of heat insulating materials interposed between one heating plate and the processing table and between the other heating plate and the pressurizing member.
A vacuum tank that houses the processing table, pressure member, heating plate, and heat insulating material,
A coil for induction heating placed outside this vacuum chamber,
Equipped with a power supply that supplies high-frequency current to the above coil,
Each of the above heating plates is a metal thin plate joining device characterized by being composed of a metal material capable of induction heating. The metal thin plate joining apparatus according to claim 1, wherein the heating plate is divided into a plurality of heat generating cells by forming a slit in the heating plate. A temperature sensor that measures the surface temperature of the heating plate and
When the value of the surface temperature of the heating plate output from this temperature sensor exceeds a predetermined upper limit value, the power supply to the coil is turned off, and when the value falls below a predetermined lower limit value, the power supply to the coil is turned off. The metal thin plate joining device according to claim 1 or 2, further comprising a control means for turning on the supply. A temperature sensor that measures the surface temperature of the heating plate and
When the value of the surface temperature of the heating plate output from this temperature sensor exceeds a predetermined upper limit value, the amount of electric power supplied to the coil is reduced, and when the value falls below a predetermined lower limit value, the power is supplied to the coil. The metal thin plate joining device according to claim 1 or 2, wherein the control means for increasing the amount of electric power is provided. Claim 1 is characterized in that a fusion prevention plate made of any one of an aluminum nitride plate, a silicon carbide plate, a graphite plate, and an amorphous carbon plate is interposed between each of the above heating plates and an object to be joined. The metal thin plate joining device according to any one of 4 to 4. The metal thin plate joining device according to any one of claims 1 to 5, further comprising a mechanism for reciprocating the coil up and down in a predetermined cycle.

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