JPH0332097A - Method and device for soldering - Google Patents

Abstract

PURPOSE:To cut off a solder better by making an angle with leads of an electronic part and a flowing direction of a solder so that the leads separate from a solder jet in turn mutually on a flowing side of the solder jet. CONSTITUTION:A printed board 2 on which an electronic part 1 is mounted with slanting is put on a transportation rail 3 having an upward inclination toward its transporting direction and is transported to the above of a soldering bath 4. When the board 2 passes through a solder S jetted from a jet duct 4a, a backside of the board 2 is immersed in the solder S to be soldered. At this time, continuous two leads of the electronic part 1 separate from the solder jet S in turn mutually on a flowing side of the solder jet S. Accordingly, a projecting direction of leads of the electronic part 1 makes an angle with a flowing direction of the solder S. Then, the solder can be cut off better even if an interval between the leads of part 1 is short, and a soldering bridge can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a soldering method suitable for mounting and soldering electronic components such as ICs having a large number of leads protruding from the side surfaces on a printed circuit board. and its apparatus.

[Conventional technology]

Conventionally, when soldering electronic components such as ICs to printed circuit boards, the leads Ia, lb, 1c, and ld protruding from the side surface of the electronic component 1 are inserted into the lead insertion holes as shown in FIG. The printed circuit board i2 on which the electronic component 1 is mounted is passed over the solder bath 4 while being transported by two parallel transport rails 3, 3, and the back side of the printed circuit board 2 is passed through the jet duct 4a of the solder bath 4. A commonly used method is to solder each lead to the conductive pattern on the back of the printed circuit board by immersing it in a jet of solder.

[Problem to be solved by the invention]

However, when soldering using the above method, the electronic component l is oriented in the direction of the transport rail 3.3 (In transport direction A).
), and the outflow direction B of the solder jet is also parallel to the conveyance rail 3°3 (opposite to the conveyance direction A) in a plan view, so that it protrudes from the front and rear sides of the electronic component 1. Ri-do la.

The protruding direction of 1c and the outflow direction B of the solder jet are parallel to each other in plan view. With such a parallel relationship, when the printed circuit board 2 passes through the solder jet, the leads Ic protruding from the rear side of the electronic component I are separated from the solder jet all at once, and the solder attached to each lead 1c is removed. Since the solder is rapidly cooled all at once, thickened and solidified, the solder tends to bleed between the leads 1c, and particularly when the distance between the leads 1c is small, solder bleed occurs frequently.

[Means to solve the problem]

The present invention has been made with the aim of solving the above-mentioned problems.The present invention has been made to solve the above-mentioned problems.The present invention has been made in order to solve the above-mentioned problems. In the method of immersing each lead in solder and soldering each lead to a conductive pattern on the back surface of a printed circuit board, each lead of an electronic component is characterized in that the timing at which each lead of the electronic component flows out from the jet solder is made different. Specifically, when a solder bath is provided perpendicular to the transport rail, a large number of consecutive leads are arranged so as not to be perpendicular to the rail. Further, when the rail and the solder bath are not perpendicular to each other, the leads are arranged to be perpendicular to the rail.

In the latter case, the soldering equipment has a soldering bath with a jet duct installed below two parallel transport rails that transport printed circuit boards carrying electronic components.
The solder bathtub is installed diagonally sideways so that the flow direction of the solder jetted from the jet duct is not parallel to the transport rail when viewed from above, and the height of the two transport rails is adjusted individually. It is characterized by being provided with an adjustment means.

[For production]

According to the soldering method of the present invention, since the lead protrusion direction and the outflow direction of the jet solder are not parallel to each other in a plan view, when passing through the jet solder, the front side of the electronic component and Not only the leads protruding from the left and right sides, but also the leads protruding from the rear side will not separate from the solder jet all at once, but will separate one by one, resulting in what is called a "solder break".
gets better.

In addition, according to the soldering device of the present invention, the solder bath is installed diagonally sideways so that the outflow direction of the jet solder is not parallel to the transport rail in a plan view, and the direction of the electronic components is adjusted. Even if it is parallel or perpendicular to the direction of the rail (conveyance direction), the protruding direction of the lead of the electronic component and the flowing direction of the jet solder are not parallel in plan view, so "solder breakage" is good. Moreover, by individually adjusting the heights of the two transport rails using the height adjusting means, it is possible to uniformly adjust the immersion depth of the back surface of the printed circuit board into the jet solder.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a partially sectional side view illustrating an embodiment of the soldering method of the present invention, and FIG. 2 is a schematic plan view of the same embodiment.

In FIGS. 1 and 2, 1 is an electronic component such as an IC with a large number of leads LA, LB, LC, and Id protruding from the four sides, and this electronic component 1 is bent into an L shape. By inserting the lower end of the lead into the lead insertion hole (not shown) of the printed circuit board i2, the transport rail 3,
It is mounted on the surface of the printed circuit board 2 so as to be oriented diagonally sideways with respect to the printed circuit board 3. 4 is a solder bath, which is installed below the conveyor rails 3.3 so that the outflow direction B of the solder S jetted from the jet duct 4a is parallel to the conveyor rails 3, 3 in plan view. ing. Therefore, the protruding directions of the leads la, lb, lc, and 1d of the electronic component 1 and the outflow direction B of the jet solder S are not parallel to each other in plan view, but have an angular relationship.

The soldering method in this embodiment is as described above for the electronic component 1.
The printed circuit board 2 mounted diagonally sideways is transported in the transport direction A.
Two parallel transport rails 3 with an upward slope toward
, 3 and send it to the upper part of the solder bath 4, and then the jet duct) 4
When passing through the solder S flowing from a, the printed circuit board 2
The back surface of the printed circuit board is immersed in jet solder S to solder each lead to a conductive pattern (not shown) on the back surface of the printed circuit board.

When soldering is performed in this way, the protruding direction of the leads of the electronic component l and the outflow direction of the solder jet S are not parallel to each other in a plan view, but are at an angle. Not only the leads la, lb, and 1d protruding from the front side and left and right sides of the component 1, but also the leads 1C protruding from the rear side one after another without leaving the jet solder S all at once. Therefore, the solder breakage of the lead IC protruding from the rear side of the electronic component 1 is improved, and the lead IC
It is possible to prevent solder blots and double jigs even if the mutual spacing between the two is relatively small.

In that case, the guide Ia protrudes from the front side of the electronic component 1.
The angle α between the protruding direction and the outflow direction B of the jet solder S is 10
'If it is smaller, it is virtually no different from the parallel state,
Since it becomes difficult to sufficiently prevent solder breakage between the lead ICs protruding from the rear side of the electronic component 1, it is preferable to set the angle α to 10' or more. '' is the best, and is extremely preferable because it provides an excellent solder bridging prevention effect.

In the above embodiment, the electronic component 1 is mounted diagonally sideways on the printed circuit board 2, and an angle is formed so that the lead protrusion direction and the flow direction of the solder jet are not parallel to each other when viewed from above. However, a conventional printed circuit board on which electronic components are mounted vertically and horizontally may be placed diagonally and horizontally on a transport rail to create an angle, and as shown in FIG. The solder bath 4 may be installed diagonally sideways to give an angle while remaining parallel or perpendicular to the solder baths 3a and 3b.

The soldering apparatus shown in FIG. 3 uses a soldering bath 4 having a jet duct 4a diagonally below two parallel transport rails 3a and 3b that transport a printed circuit board 2 on which electronic components 1 are mounted vertically and horizontally. The conveyor rail 3a is installed horizontally, and the outflow direction B of the solder jetting from the jet duct 4a is in a plan view.
, 3b, and have an angle of 10" or more so as not to be parallel to the transport rails 3a, 3b. These transport rails 3a, 3b have an upward slope toward the transport direction. are supported by support rollers 5a and 5b that can be raised and lowered to adjust the height individually, and the height of one of the conveyor jills 3a is set so that the I?i depth to the jet solder on the printed circuit board 2 is equalized. It is set slightly higher than the other transport rail 3b.

According to the device, in this type of soldering, even if the direction of the electronic component 1 is parallel or perpendicular to the transport rails 3a, 3b, the direction in which the leads of the electronic component 1 protrude and the outflow direction B of the jet solder are in a plane view. Since they are not parallel in the state, the "solder breakage" of the lead IC protruding from the rear side of the electronic component 1 is good, and solder bridging can be sufficiently prevented.
Since the height of one conveyance rail 3a is made higher than the other conveyance rail 3b by means of a and 5b, and the immersion depth of the printed circuit board 2 is made equal, no defects occur in soldering.

In this embodiment, soldering is carried out using conveyor rails 3a and 3b.
Support rollers 5a and 5b that can be raised and lowered as height adjusting means.
However, it goes without saying that various other height adjustment means may be used.

〔Effect of the invention〕

As is clear from the above explanation, according to the soldering method of the present invention, even if the lead spacing of electronic components is relatively small,
According to the soldering device of the present invention, the soldering device of the present invention has the effect that solder bridging can be sufficiently prevented due to good solder breakage. The effect is that defects can also be prevented.

[Brief explanation of drawings]

Fig. 1 is a partially sectional side view illustrating an embodiment of the soldering method of the present invention, Fig. 2 is a schematic plan view of the same embodiment, and Fig. 3 shows an embodiment of the soldering apparatus of the present invention. Schematic plan view, 4th
The figure is a schematic plan view illustrating a conventional example. l...electronic parts, la, lb, lc, ld-lead, 2...
- Printed circuit board, 3.3a, 3b...Transportation rail, 4...Solder bath, 4a...Jet flow duct, 5a, 5b...Support roller (height adjustment means).

Claims (2)

[Claims] (1) Due to the relative movement between the printed circuit board on which the electronic components are mounted and the solder jet, the numerous leads of the electronic components and the back surface of the printed circuit board are immersed in the jet solder, and each lead is soldered to the conductive pattern on the back surface of the printed circuit board. A soldering method, characterized in that the two consecutive leads of the electronic component are sequentially separated from each other from the solder jet on the outflow side of the solder jet. (2) A solder bath having a jet duct is installed below the two parallel transport rails that transport the printed circuit board, and the jet solder flowing out from the jet duct is directed against the transport rail in a plan view. A soldering apparatus characterized in that the solder baths are installed diagonally sideways so as not to be parallel to each other, and height adjusting means for individually adjusting the heights of the two conveying rails is provided.