JPH0783939B2 - Soldering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a soldering device for soldering lead terminals of electronic components on a conductor pattern provided on a printed wiring board. .

(Prior Art) As an example of this type of soldering device, conventionally, a state in which a solder layer is previously formed on the upper surface of a conductor pattern and a lead terminal of an electronic component is placed on such a conductor pattern In this configuration, the lead terminal is pressed by the heating tip made of a resistor serving as a heating means, and the heating tip is energized and heated in this pressed state to melt the solder layer, thereby performing soldering. What has been done is provided. An example of such a soldering device is Japanese Patent Publication No. 52-95.
This is disclosed in Japanese Patent No. 43, and in this case, temperature control is performed so that the heating temperature of the heating chip does not rise above a predetermined temperature.

(Problems to be solved by the invention) However, in the above-described conventional configuration, when the heating chip is cut off after the solder layer is heated and melted, the lead terminal is naturally pressed by the heating chip having a relatively large heat capacity. Since the solder is hardened by cooling, it takes a long time for the solder to harden. Therefore, there is a drawback that the time required for the entire soldering work becomes long, and there is a problem that it becomes difficult to perform automatic soldering. Further, since the heating chip, the lead terminal, the molten solder and the conductor pattern are kept at a high temperature for a long time, the internal element of the electronic component is destroyed by the heat transferred through the lead terminal, or the conductor pattern is mediated by the lead terminal. There is also a risk of causing inconvenience such as peeling off from the printed wiring board due to the influence of heat transmitted as a result.

Therefore, an object of the present invention is to shorten the time required for the molten solder interposed between the conductor pattern and the lead terminal of the electronic component to cure, and to perform the soldering work in a short time. It is an object of the present invention to provide a soldering device capable of preventing the adverse effects of heat from affecting electronic components and the like.

[Structure of the Invention] (Means for Solving the Problems) A soldering device of the present invention has a lead terminal of an electronic component on a conductor pattern provided on a printed wiring board and having a solder layer formed in advance on its upper surface. A heating means for melting the solder layer by heating while pressing the lead terminal in the mounted state is provided, and cooling air is blown to the heating means, the lead terminal, the molten solder and the conductor pattern to melt the molten solder. It is characterized in that cooling means for hardening is provided, and further control means for controlling the heating temperature and heating time of the heating means and for operating the cooling means for a predetermined time after heating by the heating means.

(Operation) After the solder layer is melted by the heating means, the cooling means is operated for a predetermined time by the control means. As a result, the cooling air is blown to the heating means, the lead terminals, the molten solder and the conductor pattern, and the heating means, the lead terminals, the molten solder and the conductor pattern are forcibly cooled, so that the molten solder is naturally cooled. Cures in a shorter time than when Therefore, the time required for the soldering work is shortened and the time when the lead terminal is kept at a high temperature is shortened.

(Example) Hereinafter, one example of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 is a conductor pattern provided on the printed wiring board 2, and a solder layer (not shown) is previously formed on the upper surface of the conductor pattern. An electronic component 3 is arranged so that its lead terminal 4 is placed on the conductor pattern 1. Reference numeral 5 denotes, for example, a heating tip, which is a pair of heating means provided on the left and right sides. This is formed by forming a resistor such as molybdenum material in a substantially U shape as shown in FIG. Is not installed). The heating chip 5 is one that is energized to generate heat when the lead terminal 4 placed on the conductor pattern 1 is pressed, so that the lead terminal 4 is heated to melt the solder layer. Has become. 6 is a heating tip 5
A thermocouple provided in the central portion of the lower side of the lower side, which outputs a temperature detection signal S ₆ having a voltage level corresponding to the temperature of the heating tip 5.

Reference numeral 7 denotes a cooling means provided in a pair on the left and right corresponding to each heating tip 5, and is composed of a blower pipe 8, a solenoid valve 9 and a cooling air supply source 10. Here, a plurality of cooling air supply holes 8a are formed in the tip portion and the peripheral side wall of the blower pipe 8, and the heating chip 5, the lead terminal 3, the molten solder are formed by the cooling air flowing out from these cooling air supply holes 8a. And the conductor pattern 1 is set to be cooled. And
The cooling air from the cooling air supply source 10 is blown and stopped through the cooling air supply hole 8a of the blower pipe 8 according to opening and closing of the electromagnetic valve 9.

Now, 11 is a control means, which will be described below with reference to FIG. Reference numeral 12 is a synchronizing signal generating circuit connected to an AC power supply 13 via input terminals I ₀ and I ₁ , which is an AC power supply.
A synchronization signal S ₁₂ synchronized with the output frequency of 13 is generated and given to the phase conversion circuit 14 and the cycle counter 15. Reference numeral 16 is a temperature setting circuit, which generates a temperature setting signal S ₁₆ of a voltage level corresponding to the temperature set by a temperature setting switch (for example, the temperature can be set in the range of 100 ° C to 599 ° C) to the comparison circuit 17. give. Reference numeral 18 denotes an amplifier circuit, which amplifies the temperature signal S ₆ given from the thermocouple 6 provided on the heating chip via the input terminal I ₂ to the amplified detection signal S ₁₈ and gives it to the comparison circuit 17. The comparison circuit 17 generates the comparison signal S ₁₇ when the voltage difference between the set temperature signal S ₁₆ and the amplification detection signal S ₁₈ (in other words, the difference between the actual temperature of the heating chip 5 and the set temperature) becomes zero. And supplies it to the phase conversion circuit 14. The phase conversion circuit 14 generates the output suppression command signal S ₁₄ at the timing synchronized with the synchronization signal S ₁₂ from the synchronization signal detection circuit 2 when receiving the comparison signal S ₁₇ , and outputs the output suppression command. The signal S ₁₄ is given to the firing pulse generation circuit 19. Thyristors 20 and 21 are connected to the ignition pulse generating circuit 19, and these thyristors 20 and 21 are connected in antiparallel to the input terminal I ₁
Connected to the output terminal O ₁ . The firing pulse generation circuit 19 is for adjusting the heating output of the heating tip 5 by controlling the conduction phase of the thyristors 20 and 21, and when the output suppression command signal S ₁₄ is input. , It operates so as to suppress the heating output from the full load output to about 1/2 load output. On the other hand, the cycle counter 15 performs a timer operation by counting the synchronization signal S ₁₂ , and the set time by a heating time setting switch (not shown, which can be set within a range of 0 to 60 seconds) has elapsed. Occasionally, a heating end signal Sa is generated, and a cooling time setting switch (not shown) (for example, 0
It is configured to repeat the operation of generating the cooling end signal Sb when a set time of (settable in the range of seconds to 20 seconds) has elapsed. The heating end signal Sa is given to both the firing pulse generating circuit 19 and the sequence control circuit 22, and the cooling end signal Sb is given only to the sequence control circuit 22. Then, the ignition pulse generating circuit 19 is operated by the thyristor when receiving the heating end signal Sa.
It is configured to stop the phase control by 20 and 21. Further, the sequence control circuit 22 is a heating end signal.
The output of the cooling signal S ₂₂ is started when Sa is given, and the cooling signal S ₂₂ is started when the cooling end signal Sb is given.
It is configured to turn off ₂₂ . Thus, the cooling signal S ₂₂ output from the sequence control circuit 22 is applied to the solenoid valve 9 via the output terminal O ₂ , and the solenoid valve 9 receives the cooling signal S ₂₂ . Will be released. Therefore, the period in which the cooling signal S ₂₂ is outputted, blown cooling air from the cooling air supply source 10 is a pipe 8
Is blown through.

23 is a welding transformer, which receives the output P ₁₁ from the output terminals O ₀ and O _{1 of the} control means 11 in the primary winding 23a,
The welding current C ₂₃ from the secondary winding 23b is applied to the heating tip 5. It should be noted that the welding transformer 23 uses the switching tap 23c provided on the primary winding 23a for the welding current C
The value of ₂₃ can be switched. Further, in the control means 11, the input terminal I ₀ and the output terminal O ₀ are directly connected.

Next, the operation of the above configuration will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, first, the heating tip 5
The temperature is from the ambient temperature T ₁ to the set temperature T ₃ (for example, about 300 ℃)
Welding current C ₂₃ from welding transformer ₂₃
As shown in FIG. 4, the phase control of the thyristors 20 and 21 is performed so that it increases between the times t ₁ and t ₂ . continue,
When the temperature of the heating tip 5 reaches the set temperature T ₃ at time t ₂ ,
The temperature detection signal S 6 from the thermocouple ₆ is given to the comparison circuit 17 via the amplification circuit 18, and in the comparison circuit 17, the set temperature T ₃
Is detected. As a result, the phase conversion circuit 14
As a result, the phase control of the thyristors 20 and 21 is performed so that the value of the welding current C ₂₃ and thus the heating output of the heating tip 5 is reduced to about 1/2 between the times t ₂ and t ₃ as shown in the fourth. . When the heating end signal Sa is output from the cycle counter 15 at time t ₃ when the set heating time has elapsed, the ignition pulse generation circuit that receives the heating end signal Sa
The phase control by the thyristors 20 and 21 is stopped by 19. At the same time, the sequence control circuit 22 receiving the heating end signal Sa starts to output the cooling signal S ₂₂ via the output terminal O ₂ , and accordingly the solenoid valve 9 is opened. Then, the cooling air from the cooling air supply source 10 is blown through the cooling air supply hole 8a of the blower pipe 8, so that the heating chip 5, the lead terminal 3, the molten solder and the conductor pattern 1 are rapidly cooled by the cooling air. To be done. When the cooling end signal Sb is output from the cycle counter 15 at time t ₄ , the sequence control circuit 22 stops outputting the cooling signal S ₂₂ , and accordingly the solenoid valve 9 is closed. The cooling is stopped. At this time, the temperature of the lead terminal 4 portion is lowered to the freezing point temperature T ₂ (about 180 ° C.) of the solder, so that the molten solder is hardened.

According to this embodiment having such a configuration, the cooling means 7 is provided, and after the heating chip 5 is heated, the cooling means 7 is operated for a predetermined time to force the heating chip 5, the lead terminals 4, the molten solder and the conductor pattern 1. Since it is designed to cool the molten solder, the time required for the molten solder to harden can be shortened as compared with the conventional method of natural cooling. Therefore, the time required for the entire soldering work is shortened, and automatic soldering can be performed. Also, since the heating chip 5, the lead terminal 4 and the conductor pattern 1 are kept in a high temperature for a short time,
There is no fear that the electronic component 3 will be destroyed by heat or the conductor pattern 1 will be peeled off from the printed wiring board 2 by heat, so that the quality of soldering can be improved.

[Effects of the Invention] As is apparent from the above description, the present invention is a state in which lead terminals of electronic components are placed on a conductor pattern provided on a printed wiring board and having a solder layer formed in advance on the upper surface thereof. A heating means is provided for heating the lead terminal while pressing it to melt the solder layer, and a cooling means for blowing cooling air to the heating means, the lead terminal, the molten solder and the conductor pattern to cure the molten solder. Further, since the control means for controlling the heating temperature and the heating time of the heating means and for operating the cooling means for a predetermined time after the heating by the heating means is provided, between the conductor pattern and the lead terminal of the electronic component. The time required for the interposed molten solder to harden can be shortened, the soldering work can be performed in a short time, and the adverse effects of heat can affect electronic components. It has an excellent effect of preventing flicker.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a side view showing the whole in a state of actual wiring, FIG. 2 is an electrical configuration diagram,
FIG. 3 is a characteristic diagram showing the temperature change of the heating tip, and FIG. 4 is a characteristic diagram showing the time change of the welding current applied to the heating tip. In the drawings, 1 is a conductor pattern, 2 is a printed wiring board, 3
Is an electronic component, 4 is a lead terminal, 5 is a heating chip (heating means), 7 is a cooling means, and 11 is a control means.

Claims (1)

[Claims] 1. The solder is prepared by placing a lead terminal of an electronic component on a conductor pattern provided on a printed wiring board and having a solder layer formed on the upper surface of the conductor pattern, and heating the lead terminal while pressing the lead terminal. A heating means for melting the layer, a cooling means for blowing cooling air to the heating means, the lead terminals, the molten solder and the conductor pattern to cure the molten solder, and a heating temperature and a heating time of the heating means are controlled. A soldering apparatus comprising: a control unit that operates the cooling unit for a predetermined time after heating by the heating unit.