JPH0723103Y2 - Automatic soldering machine - Google Patents

Description

[Detailed description of the device] [Industrial applications]

The present invention relates to a so-called solder reflow type automatic soldering machine, which mainly performs automatic soldering to a printed circuit board, and in particular, heating for soldering to the printed circuit board is extremely improved. It was done like this.

[Prior art]

The conventional automatic soldering machine of this type is configured to carry out a predetermined soldering process by transferring a printed circuit board into a so-called tunnel type furnace through a chain conveyor and bringing it into contact with molten solder. It was a thing. And, the tunnel furnace is of both-end open type,
The chain conveyor for transferring the printed circuit board has an endless shape, and although the forward path part for transferring the printed circuit board passes through the tunnel furnace, the return path part after the substrate transfer is completed,
It was constructed so as to perform a pivotal movement so as to return through the outside of the tunnel furnace.

[Problems to be solved by the device]

In the conventional automatic soldering machine as described above, both end faces of the tunnel furnace are kept open, air is freely flowing, and a chain that returns through the outside of the tunnel furnace is used. When the conveyor is returned, it is cooled by the outside air, and when it is introduced into the furnace again, there arises a problem of lowering the temperature inside the furnace, which inevitably causes uneven temperature inside the furnace and soldering. There was no choice but to cause a problem that the heating form for the product to be attached was inappropriate. Then, specifically, the conventional heating mode for the printed circuit board (the temperature rise rate based on heating) is a curve as shown by the dotted line in FIG. 3, that is, the heating is gradually performed and the maximum temperature at the time of soldering is The temperature curve is such that the rate of increase in heat is proportional to time. However, in such a heating mode, the printed circuit board is exposed to a high temperature atmosphere for a long time, and therefore,
The printed circuit board on which electronic components such as ICs were set was inevitably accompanied by the problem that it would be damaged by the adverse effects of high heat. In other words, ideally, the curve as shown by the solid line in FIG. 3, that is, the printed circuit board is preheated to a certain temperature for soldering, and the preheating temperature is maintained, It is desirable to draw a temperature curve such that the temperature rises instantaneously during the soldering work to complete the soldering process, and then the temperature drops promptly after the soldering process is completed. Made it extremely difficult to take such a temperature curve. The present invention is intended to solve the above-mentioned conventional problems.

[Means for solving problems]

The present invention defines a first preparation heating chamber 1, a second preparation heating chamber 2, and a soldering main heating chamber 3 in a tunnel furnace A, and each heating chamber has a heater for heating. A stirring fan is provided to form an independent temperature atmosphere,
Further, between the second preparation heating chamber 2 and the main heating chamber 3 for soldering, a cooling gas is produced by circulating a refrigerant gas in a tubular body wound in a coil shape. The present invention relates to an automatic soldering machine characterized in that a pipe 15 is interposed. In addition, the present invention applies the soldering target product M to the tunnel furnace A
Endless chain conveyor for moving 12 for transferring inside
Can be implemented in such a form that the whole is housed in the tunnel furnace A.

[Action]

When using the automatic soldering machine shown in the drawings as an example, the inside of the tunnel furnace A is kept in a nitrogen gas atmosphere. Then, in the inlet side airtight holding chamber 4 continuously provided on the inlet side of the tunnel furnace A, the front door 5 is opened and the rear door 6 is closed. On the other hand, the outlet side airtight holding chamber 7 connected to the outlet side of the tunnel furnace A has its front door 8 opened and its rear door 9 closed. In the above state, the endless chain conveyor for carry-in
The soldering target product M (mainly a printed circuit board) carried in through 10 is received by the feeding endless chain conveyor 11 which is housed in the inlet side airtight holding chamber 4. Through the carry-in endless chain conveyor 10, the product M to be soldered is fed into the endless chain conveyor 11
After moving to the upper side, the front door 5 of the inlet side airtight holding chamber 4 is closed, the completion of the closing is waited, and the rear door 6 is opened this time, and the inlet side airtight holding chamber 4 and the tunnel furnace A are connected. To establish communication. As a result, the nitrogen gas filling the tunnel furnace A is blocked by the front door 5 of the inlet-side airtight holding chamber 4, and therefore,
The soldering target product M is housed in the tunnel furnace A.
It is achieved without leakage of nitrogen gas to the outside. In this state, the endless chain conveyor for feeding
Turn 11 to turn the soldering target product M into the tunnel furnace A
It is transferred onto the moving endless chain conveyor 12 which is rotating inside. After completion of the transfer, if the rear door 6 is closed and then the front door 5 is opened, a preparation state for the above-described feeding operation for a new soldering target product is obtained. On the other hand, the soldering target product M introduced into the tunnel furnace A
Will be moved in the furnace by the moving endless chain conveyor 12. Therefore, the product M to be soldered is the first
After being heated in the preparation heating chamber 1 and the second preparation heating chamber 2, it is introduced into the main heating chamber 3 and a predetermined soldering operation is performed. At this time, the cooling pipe 15 is housed between the second preheating chamber 2 and the main heating chamber 3 for soldering in the tunnel furnace A. The temperature rise in the inside is suppressed, and the heating mode for the product M to be soldered exhibits the temperature rise as shown by the solid line in FIG. That is, before the rapid heating suitable for soldering in the main heating chamber 3, by maintaining a gentle temperature, continuation of high-temperature heating that adversely affects the soldering target product M itself is cut off. And, such heating depends on the rotation of the stirring fans 1c, 2c, 3c provided in the respective heating chambers, whereby the heat uniformity is achieved. In addition, the endless chain conveyor 12 for moving is the tunnel furnace A
The inside of the furnace is based on cooling of the conveyor, which occurs when the return path of the conveyor is configured to return through the outside of the tunnel furnace A, for example, because it is rotated while being accommodated in its entirety. Partial reduction of temperature or non-uniformity is prevented. After the soldering work is completed, the product is transferred to the takeout endless chain conveyor 13 housed in the outlet side airtight holding chamber 7 via the endless chain conveyor 12 for transfer. This time,
The front door 8 of the outlet side airtight holding chamber 7 is opened, and the rear door 9 is closed. Then, after the product after the soldering work is completed is transferred to the takeout endless chain conveyor 13, the front door 8 is closed, and the rear door 9 is opened after waiting for the complete closing. As a result, the takeout endless chain conveyor 13
After the soldering work is completed, the product is transferred to the endless chain conveyor 14 for unloading, and then the rear door 9 is closed and the front door 8 is opened to fill the tunnel furnace A. The nitrogen gas is blocked by the front door 5 of the outlet side airtight holding chamber 7, and therefore the product removal from the tunnel furnace A is achieved without leaking the nitrogen gas filling the tunnel furnace A to the outside. Where, the above-mentioned carry-in endless chain conveyor 10, feed-in endless chain conveyor 11, moving endless chain conveyor 12, take-out endless chain conveyor 13,
Although each endless chain conveyor of the endless chain conveyor 14 for carry-out, since each of them is independent, it does not hinder the transfer of the soldering target product to each room as described above, and each room as described above. The airtight opening and closing by the door of the can not be hindered. And, the transfer of the soldering target product M by each of the above-mentioned endless chain conveyors is as shown in FIG. 3 and FIG.
As shown in the figure, the opposing first and second endless chains a
And a soldering target product mounting projection c provided on the
And d and transfer. When the product M to be soldered is accidentally dropped during the transfer, it is received by the receiving pieces e and f provided on the first and second endless chains a and b and separated from the endless chain conveyor. Is prevented. Then, the existence of the holding pieces g and h provided on the receiving pieces e and f prevents the receiving pieces e and f from sliding down. Eventually, the soldering target product M is prevented from falling off the endless chain conveyor and leaving the endless chain conveyor in the room where the endless chain conveyor is housed.

【Example】

The structure of the present invention will be described in detail with reference to the embodiments shown in the drawings. In the drawing, A is a tunnel furnace, and inside thereof, a first preparation heating chamber 1, a second preparation heating chamber 2, and a soldering main heating chamber 3 are respectively defined. Then, in the first preparatory heating chamber 1, a first preparatory heating heater 1a, in the second preparative heating chamber 2, second preparatory heating heaters 2a and 2b, and a soldering book. Main heating heaters 3a are housed in the heating chambers 3, respectively. The inside of the first preparation heating chamber 1 and the inside of the second preparation heating chamber 2 are configured to be heated at about 140 ° C to 180 ° C, and in the main heating chamber 3, 200 ° C to 250 ° C. It is constructed so that the heating is carried out at about ° C. The tunnel furnace A forms the desired temperature rise (heating) with respect to the soldering target product M (mainly the printed circuit board) without being affected by other heating chambers by forming the heating chambers as described above. It is configured to be performed. Here, the tunnel furnace A described above is configured so that the inside thereof is constantly filled with nitrogen gas, and heating and soldering operations are performed in the nitrogen atmosphere. Although not shown in the drawings, a solder reflow type soldering mechanism is provided in the main soldering heating chamber 3. 1c is a stirring fan provided in the first preparation heating chamber 1, and 2c is a second
An agitating fan 3c provided in the preparatory heating chamber 2 is an agitating fan provided in the main heating chamber 3 for soldering, for the purpose of making the hot air in each chamber uniform. Reference numeral 4 denotes an inlet-side airtight holding chamber that is connected to the inlet of the tunnel furnace A, and front and rear doors 5 and 6 are openably and closably provided on both front and rear surfaces thereof. Further, the front door 5 and the rear door 6 are configured to perform opening / closing operations opposite to each other such that when one is opened, the other is closed. Then, the inlet side airtight holding chamber 4 is configured to communicate with the inside of the tunnel furnace A by sequentially opening the respective doors. 5a is an air cylinder for controlling the opening and closing of the front door, and 6a is an air cylinder for controlling the opening and closing of the rear door. Reference numeral 7 denotes an outlet-side airtight holding chamber that is connected to the outlet of the tunnel furnace A, and front and rear doors 8 and 9 are openably and closably provided on both front and rear mouth surfaces thereof. Further, the front door 8 and the rear door 9 are configured to perform opening / closing operations opposite to each other such that when one is opened, the other is closed. The outlet-side airtight holding chamber 7 is configured to communicate with the inside of the tunnel furnace A by sequentially opening the doors. 8a is an air cylinder for controlling the opening and closing of the front door, and 9a is an air cylinder for controlling the opening and closing of the rear door. Reference numeral 10 denotes a carry-in endless chain conveyor provided adjacent to the entrance of the inlet-side airtight holding chamber 4 for carrying a soldering target into the entrance-side airtight holding chamber 4. Reference numeral 11 is an endless chain conveyor for feeding, which is accommodated in the inlet side airtight holding chamber 4, and is for feeding the product to be soldered into the tunnel furnace A. The conveyor 11 is entirely housed in the inlet side airtight holding chamber 4. Reference numeral 12 denotes an endless chain conveyor for transfer accommodated in the tunnel furnace A, which is for moving the soldering target product from the inlet side to the outlet side in the tunnel furnace A. The conveyor 12 is entirely housed in the tunnel furnace A. Reference numeral 13 is an endless chain conveyor for taking out, which is housed in the outlet side airtight holding chamber 7, and is for taking out the soldered product from the tunnel furnace A. The conveyor 13 is entirely housed in the outlet side airtight holding chamber 7. Reference numeral 14 denotes an unloading endless chain conveyor provided adjacent to the outlet of the outlet side airtight holding chamber 7 and for delivering the soldered product from the outlet side airtight holding chamber 7. Where, the above-mentioned carry-in endless chain conveyor 10, feed-in endless chain conveyor 11, moving endless chain conveyor 12, take-out endless chain conveyor 13,
The endless chain conveyor 14 for carrying out, each of these conveyors has the following configuration. a is a double endless first endless chain, and b is a double endless second endless chain, both chain
a and b are configured to perform parallel rotation in a state where they are symmetrically opposed to each other while keeping a predetermined interval (width of a product to be soldered). Reference numerals c and d denote soldering target product mounting projections projecting from the inner surfaces of the first endless chain a and the second endless chain b, respectively. It is for doing. Reference numerals e and f are receiving pieces attached to the inner side surfaces of the first endless chain a and the second endless chain b, respectively, so as to face each other.
If an unexpected drop from c or d occurs, catch it and
This is to prevent it from falling outside the conveyor. Reference numerals g and h denote falling product holding pieces that are raised near the base ends of the receiving pieces e and f. Among the above-mentioned conveyors, at least the feeding endless chain conveyor 11 and the moving endless chain conveyor 1
2. Conveyors housed in a closed chamber, such as the endless chain conveyor 13 for sending out, have the above-mentioned configuration. Reference numeral 15 is a cooling pipe, which is also for causing a cooling action by causing a refrigerant gas such as CFCs to flow in a pipe body wound in a coil shape. Then, the cooling pipe 15 is housed between the second preparation heating chamber 2 and the soldering main heating chamber 3 in the tunnel furnace A, and the soldering target product sent through the conveyor. However, this is to obtain a temperature rise that prevents the heat from becoming high before reaching the main heating chamber 3 for soldering, that is, a temperature rise as shown in FIG. The temperature of the cooling pipe 15 is usually about 5 ° C. to 10 ° C. This is for controlling the temperature rise of the soldering target product as described above, and therefore, the size of the soldering target product. And, it is appropriately adjusted depending on the mass.

[Effect of device]

The present invention defines a first preparation heating chamber 1, a second preparation heating chamber 2, and a soldering main heating chamber 3 in a tunnel furnace A, and each heating chamber has a heater for heating. A stirring fan is provided to form an independent temperature atmosphere,
Further, between the second preparation heating chamber 2 and the main heating chamber 3 for soldering, a cooling gas is produced by circulating a refrigerant gas in a tubular body wound in a coil shape. According to the present invention, since the pipe 15 is arranged to be interposed, soldering to a product which is susceptible to heat such as a printed circuit board on which electronic components such as IC are set can be extremely well performed. Becomes That is, in the conventional automatic soldering machine, the heating mode for the product to be soldered (temperature rise rate based on heating)
Shows a curve as shown by the dotted line in FIG. 3, that is, a temperature curve in which the temperature gradually rises and reaches the maximum temperature at the time of soldering, in other words, a temperature curve in which the rate of heat rise is proportional to time. Met. Therefore, if the product to be soldered is a printed circuit board on which electronic components such as ICs are set, it will be exposed to a high temperature atmosphere for a long time (dotted line curve 2 in FIG. 3). It was inevitably accompanied by problems such as the failure of being affected by the high heat. On the other hand, according to the present invention, the heating portion of the second preparatory heating chamber 2 is the solid curve of the portion 2 shown in FIG.
Specifically, the printed board is preliminarily heated to a certain temperature for soldering, and based on the cooling action of the cooling pipe 15, the preparatory heating temperature is maintained and momentarily during the soldering work. As described above, the high temperature atmosphere is completed and the soldering process is completed, and the high temperature atmosphere can be set for only a short time during the soldering work. Therefore, the above problems in the conventional art are completely eliminated. It Further, the present invention has a structure as set forth in claim 2, that is, the whole endless chain conveyor 12 for moving for transferring the soldering target product M in the tunnel furnace A is entirely housed in the tunnel furnace A. The temperature in the tunnel furnace A is extremely stabilized and the achievement of the ideal temperature curve (solid line curve in FIG. 3) as described above is further promoted by the configuration in which it is provided in such a form. . Because the moving endless chain conveyor 12 that rotates in the tunnel furnace A is entirely housed in the tunnel furnace A, there is no possibility that the temperature inside the furnace will decrease due to the rotation. Is. That is, in the prior art, the endless chain conveyor, while the forward path for moving the soldering target product passes through the tunnel furnace, the return path after the product transfer is completed is outside the tunnel furnace. Since it was configured to perform a rotational movement so as to return through it, the part corresponding to the return path in the endless chain conveyor is cooled by the outside air, and when this is introduced again into the furnace, the temperature inside the furnace is changed. As a result, there was a problem such as temperature unevenness in the furnace. On the other hand, the present invention is based on the adoption of the above configuration,
It contributes to the stabilization of the temperature inside the furnace, such as by making the temperature inside the tunnel furnace A uniform by eliminating the occurrence of such problems, and eventually, the ideal temperature curve (solid line curve in FIG. 3) as described above is obtained. It will greatly contribute to the achievement.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a vertical sectional front view of the present invention, FIG.
FIG. 4 is a temperature graph showing a heating state of a product by a tunnel furnace, FIG. 4 is a plan view showing a main part of an endless chain conveyor, and FIG. 5 is an enlarged sectional view taken along line XX in FIG. A ... Tunnel furnace 1 ... 1st preparation heating chamber, 1a ... heating heater 1c ... stirring fan 2 ... 2nd preparation heating chamber 2a, 2b ... heating heater, 2c ... stirring fan 3 ... Main heating chamber for soldering 3a …… Heater for main heating, 3c …… Stirring fan 4 …… Inlet side airtight chamber, 5 …… Front door 5a …… Air cylinder for front door opening / closing control 6 …… Rear door 6a… … Front door open / close control air cylinder 7 …… Outlet side airtight holding chamber, 8 …… Front door 8a …… Front door open / close control air cylinder 9 …… Rear door 9a …… Rear door open / close control air cylinder 10 …… Endless chain conveyor for loading 11 …… Endless chain conveyor for feeding 12 …… Endless chain conveyor for moving 13 …… Endless chain conveyor for taking out 14 …… Endless chain conveyor for taking out 15 …… Cooling pipe a …… First endless chain b …… Second endless En c, d ...... product mounting projections e, f ...... receiving piece g, h ...... falling product retaining piece

Claims (2)

[Scope of utility model registration request] 1. A tunnel furnace (A) is provided with a first preparation heating chamber (1), a second preparation heating chamber (2), and a soldering main heating chamber (3), and Each of the heating chambers is provided with a heater for heating and a stirring fan so as to form an independent temperature atmosphere, and further, the second preparatory heating chamber (2).
And a main heating chamber (3) for soldering, a cooling pipe (15) is arranged to perform a cooling action by circulating a refrigerant gas in a coiled body. An automatic soldering machine characterized by being configured as described above. 2. A transfer endless chain conveyor (12) for transferring a product to be soldered (M) in a tunnel furnace (A), the whole of which is housed in the tunnel furnace (A). The automatic soldering machine according to claim 1, wherein the automatic soldering machine is provided in a form.