JPH0134712B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention forms a jet port above the jet tank of a solder bath, and forms a large number of uneven waves in a staggered manner on the top surface of the jet wave of the solder melt spouted from the jet port. This invention relates to a solder bath in which the uneven waves of the jet waves are moved back and forth in a direction intersecting the running direction of a printed circuit board.

Conventionally, when soldering electronic components such as resistors and capacitors temporarily attached with adhesive, or printed circuit boards with densely packed electronic components using a jet of melted solder, the direction of travel of the printed circuit board is The parts behind the electronic components and the parts where each electronic component is close to each other are shaped like recesses, where air and other gases stay and the solder melt does not flow in, so the solder melt does not adhere. Or, even if it adhered, a cavity was formed and it did not adhere completely. If bubbles are generated during one soldering process, there is a drawback that the bubbles cannot be removed even if a jet of melted solder is applied for a long period of time.

This invention was made in order to eliminate the above-mentioned drawbacks, and in order to eliminate incomplete soldering caused by air bubbles, a cylindrical jet is provided at the jet port above the solder bath, and this jet The present invention provides a solder bath in which through-holes are formed to generate jet waves, and staggered uneven waves are formed in the jet waves to further improve adhesion of solder melt. The present invention will be explained below based on the drawings.

1A and 1B show an embodiment of the present invention, FIG. 1A is a schematic perspective view of a solder bath, and FIG. 1B is a schematic perspective view of a solder bath.
is an enlarged side sectional view taken along the line - in Figure 1a, Figure 2
Figures a, b, c, and d are enlarged views of the main parts of Figure 1, Figure 2 a is a plan view, and Figure 2 b, c, and d.
are - line, - line, - in Figure 2 a, respectively.
FIG. In these figures,
Reference numeral 1 denotes a printed circuit board, which is mounted on a carrier or a substrate holder of a transport chain of a soldering device (not shown). 2 is an electronic component such as a resistor or a capacitor which is temporarily attached to the printed circuit board 1 with an adhesive or the like, and 3 is a solder tank which is formed into two tanks by a partition wall 3a provided in the center. Reference numerals 4 and 5 denote a primary tank and a secondary tank of the solder tank 3, which are arranged in sequence in the running direction of the printed circuit board 1 (direction of arrow A). 6 and 7 are solder melts in the primary tank 4 and secondary tank 5, and the solder melt 7 in the secondary tank 5 is kept at a higher temperature than the solder melt 6 in the primary tank 4. ing. Reference numerals 8 and 9 denote jet tanks installed in the primary tank 4 and secondary tank 5, in which the solder melts 6 and 7 are pressurized and forced to flow by driving a motor (not shown). Reference numerals 10 and 11 are jet ports of the jet tanks 8 and 9. 12 is a cylindrical jet, 12a is Fig. 2a
As shown in ~d, the engaging portion formed in the longitudinal direction at the lower part of the jet fluid 12 serves as the guide portion 1 of the jet port 10.
It is slidably engaged with Oa. 13
A, 13B are a large number of through holes formed vertically from the upper circumferential surface of the jet fluid 12 toward the jet port 10 at a pitch p, and the row of through holes 13A and the row of through holes 13B are mutually arranged at a pitch p. They are formed in a zigzag pattern with a difference of about /2 length. The through hole 13A is located slightly forward in the running direction of the printed circuit board 1 from the vertical center line C, which is set perpendicular to the radial direction from the axis of the jet fluid 12, and the through hole 13B is located from the vertical center line C. The height h2 of the uneven wave 6d jetted from the top of the through hole 13B is located at the rear with respect to the running direction A of the printed circuit board 1, and the height _h2 of the uneven wave 6d is set at the rear side with respect to the running direction A of the printed circuit board 1. It is formed to be lower than the height h ₁ of the uneven wave 6c jetted from the top of the hole 13A. 14 directs the jet 12 through one of the through holes 13A or 13B in the direction of arrow B.
A crank device 15, which repeats reciprocating motion by a distance of pitch d, is a rod, and one end is connected to the jet fluid 12, and the other end is connected to the flywheel 16. 17 is a motor for driving the crank device 14. Incidentally, the crank device 14 is provided away from the running direction so as not to interfere with the running of the printed circuit board 1. Reference numeral 18 denotes a jet plate of the secondary tank 5, which has a shape to form jet waves 7a of the solder melt 7 into a wave shape.

Next, the operation will be explained.

The solder melts 6 and 7 in the primary tank 4 and secondary tank 5 are
Each of them is pressurized by the drive of a motor and enters the jet tanks 8 and 9. The solder melt 6 in the primary tank 4 is
The jet fluid 12 rises from the jet tank 8 through the jet port 10.
, and is ejected upward from each of the through holes 13A and 13B, flowing forward and backward in the running direction of the printed circuit board 1, forming jet waves 6a and 6b, as well as a large number of uneven waves 6c and 6d. That is, the height h ₁ of the top of the uneven wave 6c formed at the through hole 13A of the jet fluid 12 is higher than the height h ₂ of the uneven wave 6d formed at the through hole 13B, and the first It is adapted to accommodate a printed circuit board 1 that is conveyed at an angle as shown in FIG. b. A large number of uneven waves 6c and 6d are formed in a staggered manner on the top surfaces of the longitudinal directions 6a and 6b in a direction intersecting the running direction A of the printed circuit board 1.

At the same time, the jet fluid 12 repeats reciprocating motion in the direction of arrow B due to the reciprocating drive of the crank device 14.
The large number of uneven waves 6c and 6d also repeatedly move back and forth in the direction of arrow B.

After the electronic components 2 are temporarily attached to the printed circuit board 1 using an adhesive or the like, the printed circuit board 1 is dried, then subjected to a flux treatment, and then preheated in a preheating device.
transported to. The printed circuit board 1 is placed in the solder bath 3 at an upward angle θ with respect to the horizontal line, as shown in FIG.
and travel in the direction of arrow A. And solder melt 6
Soldering is carried out by the jet wave 6a, and
Due to the large number of concave and convex waves 6c and 6d that alternately move across the running direction A of the printed circuit board 1, the rear part of the electronic component 2 and each electronic component 2 are brought close to each other with respect to the running direction of the printed circuit board 1, and the concave portion is Since air bubbles adhering to the areas having such a shape are removed, the solder melt 6 adheres well to the electronic components 2 and lead wires that are densely mounted on the printed circuit board 1. Printed circuit board 1 further advances to 2
The solder reaches the next bath 5 and is completely soldered using the high temperature solder melt 7.

As explained above, the present invention includes a jet tank which houses the solder melt in the solder tank main body and forcibly circulates the solder melt by pressurizing the solder melt with an impeller, and is provided above the jet tank. In a soldering bath where printed circuit boards on which electronic components are mounted are soldered using jet waves ejected from the jet nozzle, the top surface of the jet waves ejected from the jet nozzle has many uneven waves in the direction intersecting the running direction of the printed circuit board. In order to form a staggered pattern, a cylindrical jet having a guide portion formed in the longitudinal direction of the jet port and a slidably engaging portion is provided at the jet port, and the jet contains melted solder from the jet port. A large number of through holes that eject water are formed in a staggered manner at positions that are front and back in the running direction of the printed circuit board with respect to a vertical center line set perpendicular to the radial direction from the axis of the jet fluid. Since a crank device is connected to the jet fluid that reciprocates the uneven waves in a direction that intersects the running direction of the printed circuit board, staggered uneven waves can be easily formed on the top surface of the jet waves using a single jet fluid. In addition, with a simple configuration, the uneven waves can be easily moved back and forth in the direction intersecting the printed circuit board. Also, since the jet is cylindrical, the distance between the axis of each hole in the front row of holes and the axis of each hole in the rear row of holes relative to the vertical centerline of the jet must be changed. This makes it easy to form the upper end surface of the front through-hole row higher than the upper end surface of the rear through-hole row, and also prevents the solder melt spouting from the front through-hole row and the rear through-hole row. Since the directions of the liquid flow are opposite to each other, there are areas behind or on both sides of the electronic components relative to the running direction of the printed circuit board, or areas where electronic components are close to each other and have a recessed shape, as well as lead wires. This has the advantage that the solder melt can be completely adhered by easily removing bubbles or gas stagnation in areas where the solder is densely packed, thereby further improving the soldering performance.

[Brief explanation of drawings]

1A and 1B show an embodiment of the present invention, FIG. 1A is a schematic perspective view, and FIG. 1B is a schematic perspective view of FIG. 1A.
Enlarged side sectional view taken along line 2, a, b,
c and d are enlarged views of the main parts of Fig. 1 a, Fig. 2 a is a plan view, Fig. 2 b is a sectional view taken along the line - - of Fig. 2 a, and Fig. 2 c is a cross-sectional view of Fig. 2 a. Figure 2 a -
2d is a cross-sectional view of FIG. 2a.
FIG. In the figure, 1 is a printed circuit board, 2 is an electronic component, 3 is a solder tank, 4 is a primary tank, 5 is a secondary tank, 6 and 7 are solder melt, 6a, 6b, and 7a are jet waves, 6c, 6
d is an uneven wave, 8 and 9 are jet tanks, 10 is a jet port, 1
0a is a guide part, 11 is a jet port, 12 is a jet fluid, 1
2a is an engaging part, 13A, 13B are through holes, 14 is a crank device, 15 is a rod, 16 is a flywheel, 1
7 is a motor, and 18 is a jet plate.

Claims (1)

[Claims] 1. A jet tank is provided in which a solder melt is stored in the solder tank, and the solder melt is pressurized by a motor to forcefully jet the solder melt. In a soldering bath for soldering a printed circuit board mounted with a cylindrical jet, a cylindrical jet having an engaging portion that slidably engages with a guide portion formed in the longitudinal direction of the jet port is provided at the jet port; A large number of through holes through which the solder melt is ejected from the jet port into the jet are formed in a staggered manner from the vertical center line of the jet at positions that are forward and backward in the running direction of the printed circuit board. . A solder bath further comprising a crank device for reciprocating the jet fluid along the guide portion.