JPS6215313B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a jet-flow soldering bath in which two solder baths, a primary bath and a secondary bath, are sequentially arranged in the running direction of a printed circuit board. A large number of uneven waves are formed on the top surface of the jet wave of the solder melt ejected from the jet port provided in at least one of the jet tanks of the next tank, and the uneven waves are moved in a direction that intersects the running direction of the printed circuit board. The present invention relates to a soldering bath designed to allow

Conventionally, when soldering chip parts 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 chip parts and the parts where each chip part 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 does not stick. Alternatively, even if it adhered, a cavity was formed and it did not adhere completely. If air bubbles were generated during one soldering process, the air bubbles could not be removed even if a jet of solder melt was applied for a long period of time. Further, when performing soldering, preheating is performed, but the difference between the preheating temperature and the soldering temperature suddenly increases, resulting in disadvantages such as thermal shock being applied to the printed circuit board.

This invention was made in order to eliminate the above-mentioned drawbacks, and the solder tanks are formed by arranging them into two tanks, a primary tank and a secondary tank, sequentially in the running direction of the printed circuit board, and each solder tank is formed separately. be in control,
Furthermore, a large number of uneven waves are formed on the top surface of the jet waves of the solder melt spouted from the jet ports provided in the jet tank of the primary tank, and these uneven waves are moved in a direction intersecting the running direction of the printed circuit board. This means that the This invention will be explained below.

FIGS. 1a and 1b show an embodiment of the present invention. FIG. 1a is a side sectional view, and FIG. 1b is a partially cutaway front view showing an enlarged main part. In these figures, 1 is a printed circuit board, which is mounted on a carrier of a soldering device (not shown). 2 is a chip component such as a resistor or a capacitor which is temporarily attached to the printed circuit board 1 with an adhesive or the like; 3 is a solder tank which is formed into two tanks by a partition wall 3a provided in the center. 4 and 5 are the primary tank of the solder tank 3 and the solder tank 2.
In the next tank, they are arranged sequentially in the running direction of the printed circuit board 1 (direction of arrow D). 6 and 7 are solder melts in the primary tank 4 and secondary tank 5;
The solder melt 7 in the tank is maintained at a higher temperature than the solder melt 6 in the primary tank 4. 8 and 9 are the above 1
A secondary tank 4, a jet tank installed in the secondary tank 5, 10,
Reference numeral 11 denotes an impeller that pressurizes the solder melts 6 and 7 and forcibly circulates them, and is rotated in a fixed direction by a driving device of motors 12 and 13. 14 and 15 are flow tubes, 16 and 17 are rectifier plates, and solder melt 6,
It has a large number of holes 16a, 17a for rectifying the current. Reference numerals 18 and 19 are jet ports of the jet tanks 8 and 9. Reference numeral 20 denotes a worm-shaped rotating body provided at the jet port 18 of the primary tank 4, the main part of which is shown in FIG. 1b. Reference numeral 21 denotes a threaded portion of the rotary body 20, and a jet wave 6a of the solder melt 6 jetting from the jet port 18.
It is a means for generating uneven waves 6b on the top surface of the groove and moving the uneven waves 6b in the axial direction, and is formed by a convex portion 22 and a concave portion 23.
Reference numeral 24 denotes a rotation shaft of the rotating body 20, which is rotatably supported by the jet tank 8, and can be rotated in forward and reverse directions by a motor 25. The motors 12, 13, and 25 are provided apart from the running direction so as not to interfere with the running of the printed circuit board 1. 26 and 27 are jet plates of the secondary tank 5,
It has a shape to make the jet wave 7a of the solder melt 7 into a wave shape. 28 and 29 are the jet flow plates 2;
6, 27 are installation guides, 30, 31 are reflux ports, 3
2 and 33 are heaters.

Next, the operation will be explained.

The solder melts 6 and 7 in the primary tank 4 and secondary tank 5 are
Impeller 1 is driven by motors 12 and 13, respectively.
0,11 is pressurized as it rotates, and the flow tubes 14,1
5 and enters the jet tanks 8 and 9.

Next, the solder melt 6 that has entered the jet tank 8 of the primary tank 4 flows through the threaded portion 21 of the rotating body 20 in the direction of arrow A in FIG. At the concave portion 23 of the rotating body 20, a large amount of solder melt 6 is spouted, so the height of the solder melt 6 becomes high, and at the convex portion 22, a small amount of solder melt 6 is spouted, so the height of the solder melt 6 is high. As the height decreases, the top surface of the jet wave appears in the traveling direction of the printed circuit board 1 (Fig. 1 a).
A large number of uneven waves 6b are formed in a direction intersecting the arrow D direction).

On the other hand, the motor 25 is also driven at the same time as the motor 12 is driven, and the rotating body 20 is rotated in the direction of arrow B, so that the threaded portion 21 is apparently rotated in the direction of arrow C (see Fig. 1a).
The printed circuit board 1 moves in the direction perpendicular to the direction of arrow D, which is the traveling direction of the printed circuit board 1 shown in FIG. Therefore, when the solder melt 6 passes through the recess 23 in the direction of arrow A,
Since the side surface 22a of the convex portion 22 of the solder melt 6 apparently moves in the direction of arrow C, the uneven wave 6b on the top surface of the jet wave 6a also moves in the direction of arrow C. Next, when the motor 25 is driven in the reverse direction, the rotating body 20 rotates in the direction opposite to the direction of arrow B, and therefore the uneven wave 6b on the top surface also moves in the direction opposite to the direction of arrow C.

By repeating forward and reverse rotation of the motor 25 in this manner, the large number of concave and convex waves 6b alternately move in the direction of arrow C and in the opposite direction.

Note that the motor 25 does not necessarily need to rotate in the forward and reverse directions, but may rotate in one direction.

The solder melt 7 in the jet tank 9 flows through rectifying plates 16 and 17.
The flow is rectified by passing through the holes 16a and 17a, and is ejected from the jet port 19. The solder melts 6 and 7 spouted from the jet ports 18 and 19 of the primary tank 4 and secondary tank 5 return to the primary tank 4 and secondary tank 5, respectively, and flow through the flow pipe 14 from the return ports 30 and 31. ,15
Flow inward. In addition, the temperature of the solder melt 6 in the primary tank 4 is lower than the temperature of the solder melt 7 in the secondary tank 5, so in the primary tank 4, the conventional preheating is performed at the same time as the pre-soldering. Preheating is performed at a temperature higher than the preheating temperature of the final stage of the apparatus (heating is usually performed in several stages).

The printed circuit board 1 is dried after temporarily attaching the chip components 2 with an adhesive or the like, then subjected to flux treatment, preheated by a preheating device, and transported to the solder bath 3. In the solder bath 3, the printed circuit board 1 travels in the direction of arrow D at an upward angle .theta. with respect to the horizontal line, as shown in FIG. 1a. The chip components are soldered by the jet waves 6a of the solder melt 6, and the chip components are soldered in the direction of travel of the printed circuit board 1 by a large number of concave and convex waves 6b that alternately move across the traveling direction D of the printed circuit board 1. Since air bubbles adhering to the rear part of the chip parts 2 and the recessed parts 23 where the chip parts 2 are close to each other are removed, the chip parts 2 and the chip parts 2 which are closely mounted on the printed circuit board 1 can be removed. The solder melt 6 adheres well to the lead wires. The printed circuit board 1 further advances and reaches the secondary tank 5, where it is completely soldered with a high temperature solder melt 7.

Figures 2a and 2b show another embodiment of the present invention, in which a tubular rotating body with a large number of through holes is provided in the jet port 18, and Figure 2a is a partially cutaway front view. , FIG. 2b is a sectional view taken along the line X--X of FIG. 2a. In these figures, 41 is a tubular rotating body, and 42 is a large number of through holes formed in the rotating body 42 and arranged in a spiral shape. Otherwise, the same reference numerals as in FIG. 1 indicate the same parts.

Next, the operations shown in FIGS. 2a and 2b will be explained.
The pressurized solder melt 6 enters the through hole 42 located below the rotating body 41 from the jet tank 8 as shown by arrow A, rises through the rotating body 41, and reaches a position further above. An uneven wave 6c is formed on the top surface of the jet wave 6a ejected from the through hole 42.

At the same time, when the rotating body 41 repeats rotation in the direction of the arrow B and the opposite direction, the through hole 42 apparently moves in the direction of the arrow C and the opposite direction at the top 41a of the rotating body 41, resulting in a large number of uneven waves. 6c also repeats movement in each direction. Further, the shape of each uneven wave 6c is more finely disordered than the uneven wave 6b generated by the rotating body 20 in FIG. 1b.

Figures 3a and 3b show still another embodiment of the present invention; Figure 3a is a partially cutaway front view of the main part;
FIG. 3b is also a perspective view. In these figures,
51 is a jet tank, 52 is a jet port, 53 is an engagement groove formed in the inner longitudinal direction of the jet port 52, 54 is a rectangular plate movably engaged with the engagement groove 53, 55 Numerous through holes are formed in the plate 54, and 56 is a piston for reciprocating the plate 54 in the direction of arrow E, which is connected to the plate 54 via a rod 57.

Next, the operations shown in FIGS. 3a and 3b will be explained.
The solder melt 6 rises in the jet tank 51 and reaches the plate 54.
, and ejects from each through hole 55 in the direction of arrow A, forming a large number of uneven waves 6d.

At the same time, the plate body 5 is
4 also repeats reciprocating motion in the direction of arrow E, so the many uneven waves 6d also repeat reciprocating motion in the direction of arrow E.

4a and 4b are perspective views showing other shapes of the through holes in the plate body 54 of FIG. A large number of oval through holes are formed in a direction (also diagonal to the direction of arrow D in which the printed circuit board 1 runs);
Reference numeral 59 denotes a large number of oval through holes formed in a direction perpendicular to the direction of arrow E in which the plate body 54 moves (in the same direction as in the direction of arrow D in which the printed circuit board 1 travels).

The plate body 54 of FIGS. 4a and 4b is replaced with the jet tank 51 of FIG. 3.
When the solder melt 6 is used in a jet manner from the through holes 58 and 59, a large number of uneven waves corresponding to the shapes of the through holes 58 and 59 are obtained.

Figures 5a and 5b show still another embodiment of the present invention; Figure 5a is a partially cutaway front view of the main part;
FIG. 5b is also a perspective view. In these figures, 61 is a jet tank, which includes a jet port 62 and an engagement groove 6.
3. An insertion hole 64 is formed. Reference numeral 65 denotes an endless belt made of heat-resistant rubber, synthetic resin, etc., and has a large number of through holes 66 formed therein. belt 6
5 is slidably engaged with the engagement groove 63 and inserted into the insertion hole 64.
It is inserted through and wrapped around the drive shaft 67 and the driven shaft 68. 69 is a motor that drives the drive shaft 67.

Next, the operations shown in FIGS. 5a and 5b will be explained. The pressurized solder melt 6 enters the through hole 66 below the belt 65 as shown by arrow A, and then the solder melt 6 enters the through hole 66 below the belt 65.
A large number of uneven waves 6 are ejected from the through hole 66 above 5.
e is formed.

At the same time, when the motor 69 repeats forward and reverse rotation (in the direction of arrow B and the opposite direction), the through hole 66 above the belt 65 moves in the direction of arrow C and the opposite direction, so that a large number of uneven waves 6e are also generated. Repeat the movement in the direction of arrow C and in the opposite direction.

In the above embodiment, a means for forming uneven waves is provided on the primary tank 4 side, but this may be provided on the secondary tank 5 side, or in both the primary tank 4 and the secondary tank 5. Good too.

As explained above, the present invention forms two solder tanks, a primary tank and a secondary tank, sequentially in the running direction of the printed circuit board, and stores melted solder in each of the primary tank and the secondary tank. Then, a jet tank is installed in which the solder melt is pressurized by an impeller and forced to circulate, and the jet waves ejected from the jet ports installed above these jet tanks are used to solder the printed circuit board on which electronic components are mounted. In the soldering bath where soldering is carried out, the top surface of the jet wave forms a large number of uneven waves in a direction that intersects with the running direction of the printed circuit board, and also moves the large number of uneven waves in a direction that intersects with the running direction of the printed circuit board. Since a means for causing the printed circuit board to move is provided in at least one of the primary tank and the secondary tank, the irregular waves on the top surface of the jet wave are moved in a direction intersecting the running direction of the printed circuit board. Remove air bubbles or gas accumulation in the rear or both sides of the chip parts in the running direction, in the concave-shaped parts where the chip parts are close to each other, and in the parts where the lead wires are crowded. , has the advantage of being able to completely adhere the solder melt.

[Brief explanation of the drawing]

Figures 1a and 1b show one embodiment of the present invention. Figure 1a is a partially cutaway side view, and Figure 1b is a first embodiment of the present invention.
FIG. 2 a and b show other embodiments of the present invention; FIG. 2 b is a partially cut-away front view showing an enlarged main part of FIG. b is the second
A sectional view taken along line X--X in Figure a, Figures 3a and b show still other embodiments of the present invention, Figure 3a is a partially cutaway front view of the main part, and Figure 3b is a Perspective view,
4a and 4b are perspective views showing other shapes of the through holes in the plate shown in FIG. 3, and FIGS. 5a and 5b show still other embodiments of the present invention.
5 is a partially cutaway front view of the main part, and FIG. 5b is a perspective view. In the figure, 1 is a printed circuit board, 2 is a chip component, and 3
3 is a soldering tank, 3a is a partition wall, 4 is a primary tank, 5 is a 2
Next tank, 6 and 7 are solder melt, 8 and 9 are jet tanks, 1
0, 11 are impellers, 12, 13, 25 are motors,
14, 15 are flow tubes, 16, 17 are rectifier plates, 1
8 and 19 are jet ports, 20 is a rotating body, 21 is a threaded portion, 22 is a convex portion, 23 is a concave portion, 24 is a rotating shaft, 2
6 and 27 are jet plates, 28 and 29 are installation guides, 3
0 and 31 are reflux ports, and 32 and 33 are heaters.

Claims (1)

[Claims] 1 Solder tanks are formed into two tanks, a primary tank and a secondary tank, which are arranged sequentially in the running direction of the printed circuit board, and the solder melt is stored in the primary tank and the secondary tank, respectively. A soldering tank that is equipped with jet tanks in which the melt is pressurized by an impeller and forced to circulate, and in which the jet waves ejected from the jet ports provided above the jet tanks are used to solder printed circuit boards on which electronic components are mounted. forming a large number of uneven waves on the top surface of the jet wave in a direction intersecting with the running direction of the printed circuit board, and moving the large number of uneven waves in a direction intersecting with the running direction of the printed circuit board; A jet-flow type soldering bath, characterized in that means is provided in at least one of the primary tank and the secondary tank.