JPH01164094A - Removal apparatus of solder in through hole in substrate - Google Patents

Abstract

PURPOSE:To remove a solder remaining in many through holes in a large-sized substrate in a short time, evenly and easily without damaging the substrate by a method wherein a hot blast is jetted out from a nozzle where a heater is built-in and a solder in a molten state inside the through holes in the substrate is blown off. CONSTITUTION:The rear surface of a substrate 19 is heated up to a preset temperature by using a heater 20; after that, a potentiometer 16 and a potentiometer rod 17 are lowered by using a sensor-elevating cylinder 18. Then, they are lowered together with a movable plate 8 coupled to a nozzle 11 by using an apparatus-elevating motor 5. The rod 17 comes into contact with a substrate 22; when it is bent to a preset value, it is stopped. Only the potentiometer 16 and the rod 17 are raised by using the cylinder 18; after that, the pressurized air flows through the nozzle 11 and an electric current is applied to a heater 24 for air-heating use; when an air temperature is raised to a prescribed temperature, the nozzle 11 is slid by using a driving motor 14; a solder-removing operation in through holes in a wide area is executed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a device for removing residual solder in through-holes of a printed circuit board when replacing electronic components inserted and soldered onto a printed circuit board, and particularly relates to a device for removing residual solder in a through hole of a printed circuit board when replacing electronic components inserted and soldered therein. The present invention relates to a substrate through-hole solder removal device for removing solder in substrate through-holes using a substrate through-hole solder removal device.

[Conventional technology]

Up until now, devices for removing residual solder in board through-holes have been used to manually melt the solder in board through-holes with the tip of a soldering iron, and then remove the solder from the surrounding air using a suction device installed on the soldering iron. A device for sucking and removing solder has been proposed (Utility Model Publication No. 58-14623).
issue).

[Problem that the invention seeks to solve]

However, the above-mentioned conventional technology does not take into account the removal of solder from through-holes in large-sized boards or components. The reason is that the air from the bottom side is sucked in at the same time, the board is cooled down, and it is impossible to desolder multiple through holes with one heating, and secondly, the soldering iron is pressed against all the boards. There were problems, such as the risk of damaging patterns on the substrate.

The purpose of the invention is to do so without damaging the substrate.

To provide an apparatus capable of easily removing residual solder in a large number of through holes on a large substrate in a short time, evenly, and easily.

[Means for solving problems]

In addition to the substrate heating means, the above purpose is to include a device that injects hot air from a nozzle to melt residual solder in the substrate through-holes, and at the same time blows away the molten solder with the wind pressure.
This can be achieved by using a method of removing the nozzle, using a mechanism that allows the nozzle to slide parallel to the substrate, and using a mechanism that is provided with a sensor that detects the height of the nozzle from the substrate.

[Effect]

Since the nozzle does not come into direct contact with the board, the patterns on the board will not be damaged by removing the solder inside the board through-holes by spraying hot air from the nozzle. As a result, the board is not cooled down, and the temperature of the solder in the board through-hole can be maintained at or above its melting point for a long time.

Further, by using a mechanism that allows the nozzle to slide parallel to the substrate, solder in a large number of through holes can be removed in a short time.

Furthermore, by using a device equipped with a substrate height detection sensor, the gap between the nozzle and the substrate can always be kept constant, making it possible to apply uniform air pressure to all through holes, eliminating uneven removal. You can get uniform desoldering results without any blemishes.

〔Example〕

Hereinafter, the apparatus of the present invention will be explained with reference to the drawings.

FIG. 1 is a schematic front view showing the configuration of a hot air jet nozzle type solder removal device in a through hole of a substrate according to the present invention, in which a mounting plate 2 and a fixed plate 3 are assembled to an XY table 1.
A device elevating guide shaft 4 connects the device, a movable plate 8 is elevated and lowered between them by a device elevating motor 5, a pulley 6, and a ball screw 7.
A lunge 10, a nozzle 11 that injects hot air, a wire rope 12 that slides the nozzle 11, a pulley 15 and a nozzle slide drive motor 14, a nozzle slide guide shaft 15 that guides the slide movement, and a height of the nozzle 11 from the substrate. A potentimeter 16 for detecting the height of the substrate to be detected, and a rod 17 connected to the tip thereof. Potentiometer 16t - Cylinder 18 for raising and lowering the senna.
It also includes a heater 20 for heating the printed circuit board 197 on which the solder in the through hole is to be removed.

Figure 2 shows the state of the printed circuit board a to be soldered.
f: Schematic perspective view and partial sectional view for explanation (A-
A' sectional view) 1 under normal conditions.

An electronic component 22 having a large number of pins 21t'' is inserted into a through hole 25 of a printed circuit board 19 and soldered to it. is heated to heat the electronic component 22' (
1 and insert a new part, but when inserting the new part, it becomes necessary to remove the solder remaining in the through hole 25 to be inserted. If the target electronic component is large and has a large number of pins, the range of through-holes from which solder should be removed will be wide.

FIG. 5 is a diagram showing the structure of the hot air injection nozzle, and the nozzle 11
It has a built-in heater 24 for heating air, and has a structure that can instantaneously heat the pressurized air introduced from the compressed air inlet 25.

9. The nozzle has a constricted tip to increase the flow rate of air that blows into the board through-holes, and a wide shape that can accommodate a wide range of through-holes, allowing the nozzle to connect to the board without making direct contact with the board. They are fixed at regular intervals.

FIG. 4 is an enlarged view showing details of the nozzle slide mechanism.

FIG. 5 is a diagram illustrating a mechanism for detecting and controlling the height of the nozzle on the substrate 19 by using a height meter, and the mechanism is as follows. That is, first, (a)
As shown in FIG.
The entire device including the potentiometer rod 17 and the nozzle 11 is lowered to bring the potentiometer rod 17t into contact with the substrate 19 as shown in FIG. bend,
This is because the potentiometer is adjusted so that the distance from the tip of the nozzle 11 reaches a preset value, as shown in (o), and the device stops descending at nine points.

FIG. 6 shows a block diagram of the above control, in which the set value of the nozzle-to-substrate distance can be adjusted by adjusting the polyneum of the amplifier 27 of the potentiometer, and the nozzle height can be adjusted to remove solder. It can be positioned at the optimal distance. In other words, the potentiometer 16 has an output voltage that changes as the meter rod 17 moves up and down.When the rod 17 contacts the substrate 19 and further descends, it bends to a set value. Voltage is output. At this time, by adjusting in advance so that the amplifier 27 detects the voltage corresponding to the set value, a signal is sent to the sequencer 28 and the sequencer 2
Further, a motor stop command signal is sent from B to the overall lift motor driver 29, the motor 5 is stopped, and the entire apparatus is stopped.

Now, the desoldering operation of the present device fi=t- will be explained with reference to FIG.

First, the substrate 22 from which the electronic components have been removed in advance in the previous process is placed on the heater 20 for heating the 22-karat gold substrate, and then the XY table 1
, move the device to the position of the substrate through-hole where the solder is to be removed. Next, in order to melt the solder in the board through-hole, the board 19' is heated by the board heater 20.
@: Heat from the bottom. Here, the substrate heating heater 20
In consideration of the hot air blown from the upper surface of the substrate 19 and the adhesion of the removed solder, a far-infrared heater was used that could heat the substrate at an appropriate distance without directly contacting the substrate. After the board temperature rises to the set temperature, the potentiometer 16 and the potentiometer rod 17t
- The sensor is lowered by the cylinder 18 for raising and lowering the sensor.Then, the movable plate 8, the frame 9, 72, the nozzle 11, the potentiometer 16, and the cylinder 17t are lowered by the motor 5 for raising and lowering the device.

When the lowered potentiometer rod 17 contacts the substrate 22 and is further bent to the next preset position, the device stops descending, and the nozzle-to-substrate distance as specified is now obtained. . After this, the Botenshi attack meter is 16
After the potentiometer 17t-sensor is raised by the lifting cylinder 18, pressurized air is supplied to the nozzle 11.
A heating current is simultaneously applied to the air heating heater 24, and when the temperature of the blown air rises to the specified temperature, the dynamic motor 14, goury 15, and wire lobe 1 are activated for nozzle sliding.
2, slide the nozzle 11t and perform the soldering operation on a wide range of through holes. After the slide is completed, the supply of compressed air and electric current to the nozzle 11 is stopped, the device is raised by the device lifting motor 5, and further returned to the position at the start of operation by the XY table 1.

Through the above operations, it was possible to obtain completely satisfactory results regarding the removal of solder from the board through-holes.

〔Effect of the invention〕

As described above, when removing solder from through-holes on a board, the apparatus is configured according to the present invention, that is, an injection nozzle that slides parallel to the target board and is equipped with a sensor that detects the height from the board. By using a device that injects hot air from a hot air source, the problems of conventional devices can be solved, and many through holes on a large board can be fixed in a short time without damaging the pattern on the board. Next, it is possible to provide a substrate through-hole solder removal device that can remove solder evenly and easily.

[Brief explanation of the drawing]

Fig. 1 is a schematic front view showing the configuration of a board through-hole desoldering device according to the present invention, Fig. 2 is a schematic perspective view and partial plan view showing the state of the target board, and Fig. 5 is a hot air injection A diagram showing the structure of the nozzle, Figure 4 is an enlarged perspective view showing details of the nozzle slide mechanism, Figure 5 is a diagram to explain the nozzle height detection and control mechanism, and Figure 6 is nozzle height detection. and a block diagram showing a control mechanism.

Claims (3)

[Claims] 1. A desoldering device for through-holes in a substrate, which jets hot air from a nozzle with a built-in heater, and uses the heat and air pressure to blow off and remove solder in the through-holes of the substrate in a molten state. 2. Claim 1, wherein the nozzle is a nozzle having a mechanism that slides parallel to the substrate.
Desoldering device for substrate through-holes as described in Section 1. 3. 3. The solder removal device for substrate through-holes according to claim 1, wherein the nozzle is a nozzle equipped with a sensor that detects the height from the substrate.