JPH084931B2 - Reflow soldering machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a reflow soldering apparatus, and in particular, a reflow soldering apparatus suitable for controlling heat supply to a soldered portion at an optimum timing. Regarding attachment device.

[Prior Art] In the case of reflow soldering, variations in the heating temperature of the heating chip and variations in the amount of solder have affected the quality of solder joints and the shortening of soldering work time.

Therefore, as a solution to this problem, for example, Japanese Patent Laid-Open No.
As described in Japanese Patent No. 172791, the heating chip is pressed against the soldered portion and then the supply of the electric current to the heating chip is started at a predetermined timing, and then the melting degree of the solder in the soldered portion is adjusted. It has been proposed to detect and stop the supply of current when the degree of melting reaches a predetermined value.

[Problems to be Solved by the Invention] A conventional reflow-type soldering method controls the so-called heating time in which the supply of heating current is stopped by detecting the degree of melting of the solder, so that a sufficiently high-quality solder is used. It was difficult to join.

That is, even if the heating time is controlled according to the melting degree of the solder, the heating tip becomes higher in temperature than the solder,
Moreover, since the heat capacity is larger than that of normal solder, the conventional method of detecting the melting state of the solder and stopping the supply of the heating current has the following problems.

(1) The cooling rate of the solder becomes slow and oxidation progresses.

(2) Solder cooling time is required, which hinders reduction of takt time.

(3) Not only the crystal grains of the solder are coarsened, but also the thickness of the alloy layer formed between the soldered component and the solder is increased to reduce the soldering strength.

An object of the present invention is to solve the above-mentioned problems of the prior art, to stabilize the quality of the solder, to suppress damage to the printed circuit board to a minimum, and to reduce the takt time. To provide a mounting device.

[Means for Solving the Problems] In order to achieve the above object, in the reflow soldering apparatus of the present invention, a displacement means for displacing the heating chip toward the soldered portion, and a heating chip by the displacement means Displacement detection means for detecting displacement, heating power supply means for supplying heating power to the heating tip, and heating the heating tip from the heating power supply means to the heating tip at a predetermined timing after the heating tip is pressed against the soldered portion. Start timing setting means for starting the supply of electric power, and time measuring means for measuring the elapsed time from when the heating chip starts energizing until the degree of melting of solder reaches a predetermined value,
Displacement timing setting means for driving the displacing means at a predetermined timing to separate the heating chip from the soldered portion when the melting of the solder in the soldered portion is completed is provided.

Further, in order to supply an appropriate amount of heat to the soldered portion, the power supply means is configured to supply constant power to the heating chip.

Further, since the appropriate amount of heat is supplied to the soldered portion even if the melting time of the soldered portion changes, the power supply means can control the power supplied to the heating chip by the change of the measurement time of the time measuring means. It is configured as follows.

Then, when the time from the start of energizing the heating chip in the time measuring means until the degree of melting of solder reaches a predetermined value exceeds a preset value, the dirt attached to the surface of the heating chip It is arranged to drive a cleaning means for cleaning the membrane.

Further, when the heating power supplied to the heating tip in the heating power supply means exceeds a preset value, it is configured to drive a cleaning means for cleaning a dirt film adhering to the surface of the heating tip. It is a thing.

[Operation] In the reflow soldering apparatus according to the above method, the heating tip is separated from the solder according to the actual melt-in state of the solder, so that it is possible to prevent excessive heating and increase the cooling rate. It is not necessary to provide a cooling time in a manner that affects the soldering time, and the soldering time can be shortened.

Also, the heating power supplied to the heating tip is changed by the degree of melting of the solder in the part to be soldered, or by the change of the time from when the heating tip starts heating until the degree of melting of the solder reaches a predetermined value. By changing the amount, it is possible to supply an appropriate amount of heat to the part to be soldered and to suppress the oxidation of the solder to the minimum, thereby obtaining a solder with a fine metallographic structure, which is intermediate between the soldered component and the solder. The alloy layer that can be formed can also be formed to have an appropriate thickness.

Further, in the flow-type soldering device configured as described above, soldering can be performed easily and reliably with a simple configuration, so that the quality of solder is improved and damage to the printed circuit board is minimized. You can hold it down.

[Embodiment] Hereinafter, FIGS. 1 to 3 showing a reflow soldering apparatus according to an embodiment of the present invention will be described.

As shown in FIG. 1, a heating tip 2 made of, for example, tungsten is attached to the lower portion of the welding head 1 so as to generate heat when an electric power is applied, and a portion to be soldered is provided below the heating tip 2. The wire rod 4 and the printed circuit board 5 which constitute the above-mentioned structure and in which an appropriate amount of solder 3 is inserted are placed on the workbench 6.

Further, a displacement driving means 7 for vertically displacing the heating chip 2, a displacement driving control means 8 for controlling the driving of the displacement driving means 7, a displacement detecting means 9 for detecting the displacement of the heating chip 2, and a heating chip 2 Power supply means 10 for supplying constant power to the device, start timing setting means 11 for starting power supply from the constant power supply means 10 at a predetermined timing after the heating chip 2 is pressed against the soldered portion, and heating chip When the heating chip 2 is displaced to a predetermined value after the melting of the solder 3 is completed and the time measuring means 12 for measuring the elapsed time from the start of energization of the heating chip 2, the heating chip 2 is moved away from the part to be soldered. It is provided with a timing setting means 13, a cleaning means 14 for cleaning the heating tip 2, and a cleaning timing setting means 15 for setting the drive start of the cleaning means 14 and driving it.

 Next, the configuration of each of the above means will be described in detail.

The displacement driving means 7 is fixed to the upper surface of the bracket 701, and when a motor 702 rotatable in both forward and reverse directions is driven, a ball screw 704 connected via a coupling 703 rotates and a nut 705 screwed to this. The linear table 706 moves vertically on the surface of the bracket 701 via the. A lever 708 is supported on the linear table 706 via a shaft 707 so as to be rotatable about its center of rotation, and the lever 708 has its other end upper surface supported by a stopper 709 supported by a bracket 701. Since the clockwise rotation is restricted, the lever 708 along with the vertical movement of the linear table 706 also moves vertically while maintaining the illustrated state, and the pin 710 fixed to one end of the lever 708 is long. Since the linear table 712 supported via the connecting member 711 having the hole 711a is moved vertically along the base plate 713, the welding head 1 and the heating tip 2 supported by the linear table 712 via the welding arm 714. Moves vertically.

In addition, a screw 715 is attached to the other end of the lever 708.
Supports 716. The weight 716 has a predetermined weight, which reduces the weight of the linear table 712 and the moving parts such as the welding head 1 and the welding arm 714 supported by the linear table 712, and thus the weight 716 easily moves up and down with a small amount of power. The heating tip 2 adjusts the force for pressing the soldered portion by rotating the bonito 716 and changing its position.

When the switch 801 is closed, the displacement drive control means 8 drives the motor 702 of the displacement drive means 7 in the direction in which the linear table 706 descends, and the comparison circuit of the movement timing setting means 13
When a signal is input from 1302, the motor 702 is driven in a direction in which the linear table 706 moves up, the linear table 706 moves up and its upper surface comes into contact with the limit switch 802 fixed to the bracket 701, and a signal is output from the limit switch 802. When input, the drive of the motor 702 is stopped.

The displacement detecting means 9 is supported on the upper surface of the base plate 713,
When the linear table 712 reaches the upper end, it stops the positioning 901 and the welding arm 71 below the base plate 713.
An eddy current type displacement detector 902 which is supported at a position facing the lower surface of 4 and detects a distance from the lower surface of the welding arm 714, and a displacement meter 903 which converts displacement data from the displacement detector 902 into an electric signal.
And the amount of displacement from this displacement meter 903 is set in advance by the setter 904.
The displacement amount set in step 1, that is, the displacement amount Δ when the heating tip 2 reaches the d position shown in FIG. 2 (A),
As a result, when the two coincide with each other, the comparison circuit 905 sends a signal to the time measuring means 12.

When the signal is sent from the start timing means 11, the power supply means 10 supplies the heating chip 2 with a constant power of T ₃ for a certain period of time.

In the start timing setting means 11, when the lever 708 of the displacement driving means 7 descends, the other end upper surface separates from the lower end surface of the stopper 709, and the limit switch 1101 fixed to the linear table 706 separates, the limit switch 1101 When turned on, a signal is sent to timer 1102 and timer 1102
After a preset time T _{1 has} passed, a start signal is sent to the power supply means 10 and at the same time to the time measurement means 12.

The time measuring means 12 starts measuring time when the signal is sent from the start timing setting means 12, and when the signal is sent from the comparison circuit 905 of the displacement detecting means 9,
The time measurement is completed, and the time data during that time is sent to the cleaning timing setting means 15.

Moving timing setting means 13, the heating chip 2 with temporarily storing displacement amount E _n from the displacement meter 903 of the displacement detecting means 9 when reaching the f position shown in FIG. 2 (A), x th previous a memory 1301 of selecting the displacement amount E _nx, compared to x th previous displacement E _nx of displacement and memory 1301 from the displacement meter 903, reach the displacement E _n is E _n ≧ E _nx from the displacement meter 903 At this time, a signal is sent to the displacement drive control means 8 to drive the motor 702 in the direction in which the linear table 706 is raised so that the heating chip 2 is separated from the soldered portion.

The cleaning means 14 is a cylinder supported by a bracket 1401.
When the piston 1402 is driven, the piston rod 1403 is moved forward in the axial direction, and the upper surface of the cleaning member 1404 attached to the tip of the piston rod 1403 cleans the lower surface of the heating tip 2.

When the time data from the time measuring means 12 is sent to the comparison circuit 1501, the cleaning timing setting means 15 compares the time data with the time data T ₂ preset in the setter 1502, and measures the time as a result. When the time data from the means 12 is larger, a signal is sent to the cylinder controller 1503. In the cylinder controller 1503, it is confirmed that the upper surface of the linear table 706 is in contact with the limit switch 802 of the displacement drive control means 8, that is, that the heating tip 2 has reached the upper position apart from the soldering portion. After confirmation,
It is configured to drive the cylinder 1402 of the cleaning means 14.

Next, the operation will be described with reference to FIGS. 2 and 3.

FIG. 2 is an explanatory view showing the relationship between the displacement of the heating tip and the supply power, and FIG. 3 (A) shows the state in the vicinity of the soldered portion before supplying the electric power to the heating tip. B)
Shows the state near the soldered part when the solder is completely melted.

When the switch 801 is closed and the motor 702 of the displacement driving means 7 drives the linear table 706 in the descending direction, the linear table 706 descends and the welding head 1 and the heating tip 2 descend by the same amount.

Then, when the heating chip 2 comes into contact with the soldered portion and further descends to reach the position a shown in FIG. 2 (A), the upper surface of the linear table 706 is separated from the lower end surface of the stopper 709 to the third position. As shown in FIG. 3A, the heating chip 2 presses the soldered portion with a predetermined force.

At this time, the limit switch 1101 is also separated from the upper surface of the linear table 706, the limit switch 1101 is turned on, and a signal is sent to the timer 1102. Timer 1102 when the heating Chibbu 2 reaches the position b after the lapse of T ₁ preset time, send a start signal to the power supply unit 10 supplies a predetermined time T ₃ constant power W ₁ to the heating chip 2 At the same time, it is sent to the time measuring means 12 to start the time measurement.

Then, when the heating tip 2 reaches the position c after a certain time has passed since the heating was started, the solder 3 starts to melt,
At the same time, the heating chip 2 descends by itself as the solder 3 melts.

After that, the heating tip 2 descends to the position d, and the detector 902 detects this, and the comparison circuit 905 compares the displacement amount from the displacement meter 903 and the displacement amount Δ preset by the setting device 904.
Are compared, and when the two match, the comparison circuit 905
The signal from causes the time measuring means 12 to stop measuring time. At this time, when the time data required for the time measuring means 12 to supply the heating chip 2 to be displaced by the displacement amount Δ is sent to the comparison circuit 1501, the comparison circuit 1501 is preset by the setter 1502. When the time data from the time measuring means 12 is larger than the time T ₂ , the signal is sent to the cylinder controller 1503.

However, in the cylinder control unit 1503, the limit switch 802 is not in contact with the upper surface of the linear table 706 yet, and therefore the cylinder control unit 1503 is on standby.

Subsequently, the heating tip 2 descends as the solder 3 melts, reaches the position e, and enters the state shown in FIG. 3 (B), and when the heating tip 2 stops descending, the displacement meter 903
And the displacement amount E _x from, x pieces before the displacement amount E from the memory 1301
_{When the} heating chip 2 reaches the point f where E _nx ≦ E _{x as a} result of comparison with _nx by the comparison circuit 1302, a signal is sent from the comparison circuit 1302 to the displacement drive control means 8 and the motor 702 is moved to the linear table 706. The heating tip 2 by driving it upward
Away from the soldered part.

At this time, constant power is continuously supplied from the power supply means 10 to the heating tip 2, but since the heating tip 2 is separated from the soldering portion, it is necessary to prevent the soldering portion from being excessively heated. You can

Then, when the heating tip 2 moves up to a predetermined position and the upper surface of the linear table 706 comes into contact with the limit switch 802, the driving of the motor 702 is stopped via the displacement drive control means 8.

Further, since a signal is sent from the limit switch 802 to the cylinder control unit 1503, the cylinder control unit 1503 uses the cleaning means.
By driving 14 cylinders 1402, the lower surface of the heating tip 2 can be cleaned by the upper surface of the cleaning member 1404.

Therefore, in this embodiment, the heating tip 2 is separated from the solder in accordance with the actual melting degree of the solder to supply an appropriate amount of heat to the portion to be soldered. The result is that the oxidation of the solder is minimized, a solder having a fine metal structure is obtained, and the alloy layer formed between the component to be soldered and the solder 3 has an appropriate thickness. Moreover, it is not necessary to provide the cooling time in a manner that affects the takt time, and the soldering time can be shortened.

Also, when the time from the start of heating until the degree of melting of solder reaches a predetermined value is exceeded, the heating tip 2 is cleaned, so the cleaning interval is lengthened to minimize the effect of cleaning time on the takt time. By detecting the contamination of the heating tip 2 beforehand,
Since the dirt of can be kept below a certain value at all times,
The quality of the soldered part can be stabilized.

In addition, the cleaning timing setting means drives the cleaning means when the time until the amount of melted solder due to the constant heating power from the power supply means reaches the predetermined value exceeds the predetermined time. The time can be easily detected.

In addition, each operation described above can be easily and surely performed with a simple configuration.

In this embodiment, the case where the wire rod is a bare wire has been described, but the present invention is not limited to this and can be applied to the case of a covered wire. However, in the case of the covered wire, the melting temperature of the solder is lower than the melting temperature of the covering portion, so that as shown in FIG. 2 (C), the power value supplied from the power supply means to the heating chip is changed to the covering portion. It is necessary to supply two types of power values for melting and solder melting power to the heating chip.

Next, FIGS. 4 and 5 showing a soldering apparatus according to another embodiment of the present invention will be described.

The present embodiment shown in FIG. 4 and the embodiment shown in FIG. 1 are different from each other in the power supply means, the time measuring means and the cleaning control means. The same parts are designated by the same reference numerals as in FIG.

The electric power supply means 10 'is supplied to the heating chip 2 for a predetermined time by a signal from the timer 1102 of the start timing setting means 11.
It is configured to supply the T ₃ electric power and measure the electric power value at the time of the next soldering according to the size of the data regarding the measuring time T ₂ ′ from the time measuring means 12 ′. That is, as a result of sending the power value set from the power supply means 10 'to the comparison circuit 1501' of the cleaning control means 15 'and comparing it with the power value set by the setting device 1502', the power supply means 10 ' Since the set electric power value is smaller than the electric power value W ₁ set by the setter 1502 ', as shown in FIG. 5 (A), the heating chip 2 receives a predetermined amount of displacement Δ after the electric power is supplied. When the time T ₂ ′ until reaching T ₂ becomes longer than the predetermined time T ₂ , the comparison circuit 1501 ′ determines that the cylinder controller 1503
The power value W ₂ supplied to the heating tip ₂ is increased within a range in which no signal is sent to the heating chip 2.

The time measuring means 12 'starts time measurement by a signal from the timer 1102 of the start timing means 11, finishes time measurement by a signal from the comparison circuit 905 of the displacement detecting means 9, and supplies time data during that time to the power supply means. It is configured to send to 10 '.

The cleaning control means 15 'compares the electric power value from the electric power supply means 10' with the electric power value W ₁ set by the setting device 1502 ', and feeds back the result to the electric power supply means 10' and at the same time, the electric power supply means 10 '. If the electric power value from ′ becomes large due to a film of dirt adhering to the heating tip 2, the comparison circuit 15
A signal is sent from 01 'to the cylinder controller 1503 to clean the heating tip 2 when it reaches the rising end.

Therefore, in this embodiment, in addition to the effect of the embodiment shown in FIG. 1, the electric power value supplied to the heating chip 2 can be controlled, so that an appropriate amount of heat can be supplied to the soldered portion. it can.

[Advantages of the Invention] Since the present invention is configured as described above, it has the effects described below.

It controls the timing to separate the heating tip from the solder according to the actual melting degree of the solder and supplies an appropriate amount of heat to the soldered part, so it is possible to prevent excessive heating and improve the cooling rate. Oxidation of the solder is minimized by using the method, a solder with a fine metal structure can be obtained, the alloy layer formed between the soldered component and the solder has an appropriate thickness, and cooling is performed in a manner that affects the duct. It is not necessary to provide time, and the soldering time can be shortened.

Further, since the soldering can be performed easily and surely with a simple structure, the quality of the solder can be improved and the damage to the printed circuit board can be suppressed to the minimum.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a reflow type soldering device according to an embodiment of the present invention, and FIGS. 2 (A) and 2 (B) are explanatory views showing the relationship between the displacement of a heating tip and the supply power. FIG. 2 (C) is a power supply diagram when a covered wire is used as a wire material for inserting solder, and FIG. 3 (A) shows a state near a soldered portion before supplying power to a heating chip. FIG. 3 (B) shows a state in the vicinity of the portion to be soldered when the solder is completely melted, and FIG. 4 is an explanatory view showing a reflow type soldering apparatus according to another embodiment of the present invention. FIG. 5 is an explanatory diagram showing the relationship between the displacement of the heating tip and the supplied power. 1 ... Welding head, 2 ... Heating tip, 3 ... Solder,
4 ... Wire rod, 5 ... Printed circuit board, 7 ... Displacement drive means, 8 ... Displacement drive control means, 9 ... Displacement detection means, 10
...... Power supply means, 11 …… Start timing setting means, 12 …… Time measuring means, 13 …… Movement timing setting means, 14 …… Cleaning means, 15 …… Cleaning timing setting means

Front page continued (72) Inventor Masao Yoshio, 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Pref., Institute of Industrial Science, Hitachi, Ltd. In the factory (56) Reference JP 62-172791 (JP, A) JP 63-84764 (JP, A) JP 61-135476 (JP, A)

Claims (5)

[Claims] 1. A reflow-type soldering apparatus for pressing a heating chip against a soldered portion to melt solder between members to be soldered, and displacing means for displacing the heating chip toward the soldered portion. Displacement detecting means for detecting the displacement of the heating chip by the means, heating power supplying means for supplying heating power to the heating chip, and heating power supplying means at a predetermined timing after the heating chip is pressed against the soldered portion. Start timing setting means for starting heating power supply from the heating tip to the heating tip, time measuring means for measuring elapsed time from when the heating tip starts energizing until the degree of melting of the solder reaches a predetermined value, and a soldered portion When the melting of the solder is finished, the displacement means is driven at a predetermined timing to separate the heating tip from the soldered part. Reflow soldering apparatus having a displacement timing setting means that. 2. The reflow soldering device according to claim 1, wherein the power supply means is configured to supply a constant power to the heating chip. 3. The reflow soldering device according to claim 1, wherein the power supply means is configured to control the heating power supplied to the heating chip by changing the measurement time of the time measuring means. 4. When the time from the start of energizing the heating chip in the time measuring means until the degree of melting of solder reaches a predetermined value exceeds a preset value, it adheres to the surface of the heating chip. The reflow soldering device according to claim 1, wherein the reflow soldering device is configured to drive a cleaning unit that cleans a dirt film. 5. When the heating power supplied to the heating chip in the heating power supply unit exceeds a preset value, the cleaning unit for cleaning the dirt film adhering to the surface of the heating chip is driven. The reflow soldering device according to claim 1, which is configured.