JPH0530849Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a jet soldering device used for soldering printed circuit boards and the like.

Prior Art Electronic circuit devices use devices in which electronic components are mounted on a printed circuit board on which a conductive pattern is formed, and the electrodes of the electronic component and the conductive pattern are electrically connected to form an electronic circuit. Electrical connection between the electrode and the conductive pattern is generally performed by soldering.

As a soldering device used for soldering here, there is a jet type soldering device in which a duct is arranged in a solder tank with the open end protruding from the static soldering surface, and molten solder overflows from the duct. This jet soldering device is widely used because the solder overflows from the end face of the duct, so the end face of the duct does not become an obstacle to the movement of the printed circuit board.

On the other hand, in order to improve the mounting density of electronic components on a printed circuit board, a double-sided printed circuit board is used, and chip components are inserted into the back side of the board, and components with leads are inserted from the front surface of the board. There were cases where voids were formed.

In order to improve this problem, JP-A-60
A soldering device having a structure disclosed in Japanese Patent No. 37261 is known.

This will be explained with reference to FIG. In the figure, 1 is a solder tank containing molten solder 2, and 3 has one end connected to the solder tank 1.
A first duct 4 is located inside the first duct and has its other end open upward, and is located close to the first duct 3 in the same manner as the duct 3, and has an upper end located above the upper end of the first duct 3. 5 is a solder pool adjacent to the second duct, and 6 is a circulation path for molten solder. The first and second ducts 3 and 4 communicate at their lower ends, are separated from a circulation path 6 by a partition wall 7 on the first duct 3 side, and communicate with the circulation path 6 on the solder pool 5 side.

Although not shown, a heater is disposed within the solder bath 1, and a pump means for feeding solder liquid into the first and second ducts 3 and 4 is also disposed.

This operation will be explained below. When the solder liquid 2 is sent to the first and second ducts 3 and 4 by the pump means, the solder liquid 2 overflows from each duct 3 and 4, and the solder liquid 2 flows into the first and second ducts 3 and 4.
The solder liquid 2 overflowing from the second duct 3 flows into the circulation path 6, and the solder liquid 2 overflowing from the second duct 4 once passes through the solder reservoir 5 and flows into the circulation path 6, and is again sent to each duct by the pump means. .

Here, the solder liquid discharged from the first duct 3 has a single peak shape as shown in the figure, and the solder liquid discharged from the second duct 4 has a trapezoidal shape because a certain amount of solder liquid overflows from the solder reservoir 5. It flows out in a rectified state.

For such a soldering device, a printed circuit board (not shown) is placed on a moving path A indicated by a dashed line in the figure.
By moving the first duct, 3 parts of the first duct come into contact with the turbulent solder to eliminate voids in areas where chip parts and leads are concentrated, and then solder is made in the 4 parts of the second duct, which is in a rectified state. The finish can be improved.

Problems to be Solved by the Invention By the way, in the device shown in FIG. 3, the solder in the first duct 3 has a single-peaked cross section, and the positional relationship between the movement path A of the printed circuit board and each duct 3, 4 cannot be easily changed. Therefore, it has been difficult to maintain an appropriate immersion depth of the solder into the printed circuit board and set an appropriate immersion time. That is, if the moving speed is increased in order to shorten the soldering processing time, the contact time between the printed circuit board and the solder becomes shorter, resulting in uneven soldering. Therefore, even if the amount of solder discharged from the ducts 3 and 4 is increased and the solder discharge height is increased, not only will it not be possible to set the contact time of the solder to the printed circuit board appropriately, but also the solder liquid will wrap around the printed circuit board. There was also the risk of damaging the circuit itself.

Means for solving the problems This invention was proposed in view of the above problems.
The diameter of the discharge ports provided in one jet duct is increased sequentially along the conveyance direction of the soldering object, and the jet flow height is set as a resistance means for limiting the height of the soldering jet. It is characterized by being set higher sequentially along the conveyance direction.

Embodiment An embodiment of the present invention will be explained below by applying it to the apparatus shown in FIG. 3, starting from FIG. In the figure, the same reference numerals as in FIG. 3 indicate the same parts, and the explanation will be omitted. In the figure, what is different from the device in Figure 3 is the discharge port 8 of the first duct 8.
a, 8b, and 8c are sequentially provided with larger diameters in the moving direction of the printed circuit board moving path A (arrow shown in the figure), and the cross-sectional shape of the solder liquid 2 discharged from the first duct 8 is multimodal, and each discharge port 8a, 8b, 8c The only difference is that the jet heights of the solder liquids 2a, 2b, 2c that are discharged are set higher in the direction of the arrows in the figure.

This increases the contact area between the printed circuit board and the solder in the first duct 8 portion.

Therefore, since the immersion depth for the printed circuit board can be properly maintained and the immersion distance can be increased, the solderability can be maintained good and the moving speed of the printed circuit board can be increased.

Effects As described above, according to the present invention, the height of the jet of molten solder overflowing from one jet duct is set higher in one direction by the simple means of changing the diameter of the discharge port. It is possible to easily manufacture a soldering device that can widen the contact area between the solder and the solder, maintain an appropriate immersion depth, and maintain good solderability even when the moving speed of the printed circuit board is increased.

[Brief explanation of the drawing]

1 and 2 show embodiments of the present invention, FIG. 1 is a side sectional view showing the first embodiment, and FIG. 2 is a side sectional view showing the first embodiment.
FIG. 3 is a side sectional view showing an example of a conventional soldering device. 8... Jet duct, 8a, 8b, 8c... Discharge port.

Claims (1)

[Claims for Utility Model Registration] Discharge ports provided in one jet duct are gradually increased in diameter along the conveying direction of the soldering object, and the discharge ports are used as resistance means to limit the height of the solder jet. A soldering device characterized in that the height of the soldering object is gradually increased along the conveyance direction of the soldering object.