KR900006977B1 - Vibratory wave soldering of printed wiring boards - Google Patents

Abstract

In a wave soldering process an oscillation is produced in the solder wave during the passage of an element through the wave. A vibrating vane is provided in the solder wave on the end of a connector rod which is connected to a vibrator located away from the wave. Oscillation or vibration aids in filling small holes in a board, crevices, corners adjacent to solder masks and other areas where solder wetting is difficult to achieve with conventional machines. A relatively high frequency oscillation in the solder wave displaces or dislodges gas bubbles that form beneath the boards.

Description

Vibratory fluid soldering method for printed wiring boards and apparatus therefor

1 is a cross-sectional view of a solder wave applied to the bottom surface of a wiring board showing one embodiment of the oscillating blade,

2 is a cross-sectional view of a solder wave, showing another embodiment of a vibrating blade,

3 is a plan view of the oscillating blade shown in FIG.

4 is a cross-sectional view of a solder wave, showing another embodiment of a vibrating blade,

5 is a cross-sectional view of a blister wave showing another embodiment of a vibrating blade having a liquid surface additive supply pipe,

6 is a side isometric view of the oscillating vane shown in FIG.

* Explanation of symbols for main parts of the drawings

10: nozzle 11: ram lead supply conduit

12 flange 13 solder port

14: path 15: printed wiring board

16 elements 17 contact

20: induction device 2l: weir plate

30,40: vibration blade 31,41: connecting rod

32,42: gap 33,44: vibrator

43: end plate 50, 51, 52: shaking table

53: manual wing 54: exit passage

55: surface additive supply pipe 56: oil reservoir

FIELD OF THE INVENTION The present invention relates to weave soldering of chained wiring boards. More specifically, the present invention relates to the surface of printed wiring boards as well as the flow soldering of standard components on one side, both sides and / or multilayer boards. mounted devices) or components for flow soldering.

New technologies in electronic component calculation have introduced devices such as resistors, capacitors and integrated circuits in the form of chip components. These parts are usually mounted on the bottom surface of the printed wiring board with adhesive. These conditions raise new questions about existing payment methods.

The present method of flow soldering elements on a printed wiring board includes a scheme with two solder waves. The first fempa is typically narrow in width and has a single stream parabolic shape. Narrow waves contact a small area of the wiring board to allow gas to escape. The gases are generated by the volatiles of the solvent, which can inhibit solder wetting. Narrow waves also provide vertical pressure to allow solder to enter narrow gaps and gaps between components, ensuring that all circuit pads, components, terminations, and contacts are wetted with solder.

The second solder wave is typically a solder wave used to solder a printed wiring board with leaded components or the like in a commercially available machine. The second digging method completes and provides optimum drainage conditions for the printed wiring board leaving the solder wave so that excess solder deposits are minimized or eliminated to remove bridges between the contacts.

The double solder wave method is effective for soldering elements on a printed wiring board, but it has been found to have some drawbacks. One problem is the overproduction of dross (oxides). Dual wave systems typically produce up to twice as many dross as single wave systems. Another problem is that it is difficult to precisely control the turbulent parabolic solder waves. The best soldering results are obtained by immersing the printed wiring board as deep as possible in this hole. However, turbulence in waves can make this difficult and can cause the solder to overflow to the top surface of the printed wiring board.

One object of the present invention is to overcome the above-mentioned problems and to provide a method and apparatus for flow soldering elements such as printed wiring boards with elements embedded on the substrate surface.

Another object of the present invention is to provide an oscillating wave with adjustable vibration or oscillation, as opposed to random turbulance. As used throughout this specification, the terms “vidbration” and “oscillation” refer to frequencies of about 20 KHz or less.

SUMMARY OF THE INVENTION The present invention provides a method and apparatus for flow soldering elements such as components embedded on a surface on a printed wiring board, wherein the solder wave is oscillated or vibrated while the printed wiring board passes through it. Oscillation or vibration helps to fill small holes in the substrate, cracks, edges adjacent to the solder mask, and all other areas where conventional soldering is difficult to achieve solder wetting. An additional benefit is that the problems caused by thick dry film solder masks are overcome. Relatively high frequency oscillations within the solder wave move or remove gas bubbles formed under the substrate, allowing the solder to reach all areas within the component substrate of the printed wiring board, and any metallization, such as component bodies or solder masks. It overcomes the repulsion effect of unabsent members.

Moreover, the vibration or oscillation concept of the present invention can be applied to existing solder wave machines for the present type of flux solder as a temporary or permanent facility for soldering which is rather difficult to solder.

According to the present invention, a member is moved to a predetermined source path, and a solder wave is formed under the path so that at least a part of the sub-subject passes through the wild wave, and vibration is generated in the solder wave while the member passes therein. It provides an out-of-member flow soldering method consisting of steps to make.

Preferably the oscillation frequency and / or oscillation amplitude are adjusted and at least one vibrating zone is formed in the solder wave. In one embodiment, the vibration occurs in a direction substantially parallel to the out-of-member path, and in another embodiment, the vibration occurs in a direction substantially perpendicular to the out-of-member path.

In the present invention, a means for forming a small wave, a means for moving the wiring board in a path so that the lower surface of the wiring board passes through the solder wave, and vibration is generated in the solder wave while the wiring board passes through the inside thereof. There is also provided a flow soldering device such as an element on a printed wiring board composed of oscillation means.

In one embodiment, the oscillating means consists of at least one oscillating vane in the solder wave and at least one connecting rod connecting the vane to a vibrator means located away from the solder wave. In yet another embodiment, the at least one oscillating wing is in the form of a flat strip and extends into a solder wave substantially perpendicular to the path of the wiring board, the oscillating means being in a direction substantially parallel to the path of the wiring board. Vibrate the flat strip. In another embodiment, a plurality of vibrating wings are coupled by a connecting rod, and the vibrator means vibrates the vanes in a direction substantially perpendicular to the path of the wiring board. Means for adjusting the amplitude and / or frequency of vibrations are preferably provided in a frequency range of about 20 cycles / second to about 400 cycles / second and an amplitude of at least about 1.5 mm (0.060 inch). Furthermore, the position of the blade of the soldering band is preferably adjustable. In one embodiment, means are also provided to selectively supply an oily surface additive to the solder wave.

In another embodiment, a solder wave is formed from the discharge nozzle, which is positioned upwards and directed above the solder reservoir with the pump means to form the solder wave from the nozzle. The oscillating blade is in one embodiment positioned on the solder waveband and at least two oscillating bands are formed.

In yet another embodiment, at least one adjustable passive blade is located downstream of the solder wave from the discharge nozzle at the member exit side, and the position of the passive blade may be in contact with another shaking table. To help separate components such as wiring boards from soldering wires.

At least one liquid surface additive feed tube may be located downstream of the manual blade and means are provided to supply the liquid surface additive to the solder wave surface through the feed tube.

Hereinafter will be described according to the drawings.

1 and 2 show cross-sectional views through a typical solder wave nozzle 10 as shown in Canadian Patent No. 1,002,391 to Elliott et al. The nozzle 10 is connected to the solder supply conduit 11 by a flange 12. The solder enters the nozzle 10 and forms a solder wave of a desired shape. The solder flows backward to the solder port 13.

There is a wiring board path 14 through which the wiring board 15 is carried on the solder port 13. Although the figures show a straight sloped path 14, the present invention can be applied to a solder wave machine having a lifetime or a curved path. The printed wiring board 15 includes elements 16 having pads and contacts 17 which are covered with solder to make soldered connections. At the entry side of the exposure 10 there is a guide 20 providing a downward sloped path to a portion of the solder. The discharge solder wave flows up to the weir plate 21.

1 shows a vibrating blade 30 in the form of a flat strip extending along the length of the nozzle and positioned on the nozzle 10 stage. The upper edge of the vane 30 is shown at substantially the same height as the upper edge of the nozzle 10. Optionally, the upper edge of the vanes 30 may be lower than the upper edge of the nozzle, or may be higher than the upper edge of the nozzle if the upper edge of the nozzle is not high enough to prevent passage of the assembly being soldered.

A connecting rod 31, which may be two or more rods in some nozzles, supports the vanes 30 past the gap 32 on the outlet side of the nozzle 10. The rods 3l are connected to a vibrator 33 positioned away from the solder nozzle 10 on the solder port 13. The exact position of the vibrator 33 as well as the rods 31 with respect to the wing or wings 30 can be varied. The vibrator can be located above or below the soldered portion, and the vibration is reliably transmitted to the wing 30. Be sure to The vibration amplitude and / or frequency is adjustable by vibrator 33. By vibrating the solder wave in a sufficient amount, the gas bubbles formed under the wiring board 15 are moved or removed, the solder reaches the component cluster, and the other makes it difficult to reach the soldered area. Large gas bubbles can be broken down into smaller bubbles, and all of the bubbles move in succession, allowing the solder to reach all areas. The vibration is also sufficient so that the molten solder is pushed up to both sides of the elements to overcome the repulsion effect of the non-metalized part body. The solder then forms wet or necessary solder joints in the area of the metal being soldered, such as component clusters, pads, and the like. The vibration frequency together with the vibration amplitude can be adjusted to suit different types of wiring periods.

2 and 3 show yet another embodiment, in which a series of independent short vanes 40 are positioned perpendicular to the length of the nozzle 10 and a connecting rod 41 connects all the vanes 40 together. Let's do it. As one connecting rod 41 is shown, it is obvious that two or more rods can be used if necessary. The connecting rod 41 is supported in the gap 42 in the end plates 43 of the nozzle 110 and is connected to the vibrator 44 so that the vibration occurs in a different plane than that shown in FIG. 1 shows that vibration or oscillation occurs substantially parallel to the curvature of the wiring board path 14, and FIGS. 2 and 3 show that vibration or oscillation occurs substantially perpendicular to the movement of the wiring board path 14. Shows. The position of the vanes 40 in the nozzle 10 may be raised or lowered and the number of vanes 40 may depend on a particular type of soldering machine and a particular type of printed wiring board to be soldered. . The size, shape, quantity and angle of the wings can be varied as desired. Vibration or oscillation may be applied at any angle between the two directions shown in FIGS. 1 and 2.

In the embodiment shown in FIG. 4, the vibrating blades 30 are connected to the vibrator 33 by one or more connecting rods 3l. As shown in this figure, the upper edge of the oscillating wing 30 is more or less protruded over the upper edge of the nozzle 10. The upper edge of the blade 30 should not interfere with the elements on the wiring board 15. The position of the vibration blades 30 can be adjusted to optimize vibration characteristics and soldering results. The wiring board path of FIG. 4 is inclined 6 degrees upward in the moving direction. The angle of inclination of the path may vary from about 0 ° -10 ° depending on the type of soldering machine.

In the embodiment shown in Figs. 4 and 5, two solder wave shake tables 50 and 51 are shown, one on each side of the vibrating blade 30 under the wiring board 15. have. These shake tables 50 and 51 allow the solder to reach all areas where solder wetting is required. Another shake table or shake table 52 is formed using the manual blade 53 on the outlet side of the nozzle 10 in front of the weir plate 21. The passive blade 53 is positioned at the most suitable position so as not to disturb the components of the printed wiring board 15, and another shake table 52 is preferably formed between the nozzle and the weir. In one embodiment, another shaking table occurs at or near the point at which the substrate 15 is separated from the solder wave. This further vibration applied to the solder wave and the substrate in another shake table 52 reduces the probability that the bridge occurs between the contacts or between the pads. The passive blade 53 also has a damping effect on the solder located between the weir 21 and the manual blade 53. The U-shaped water wing 53 shown in the figure can be located at different locations within the outlet passage 54 to change the position of another shaking table 52.

5 and 6 are modifications of the apparatus shown in FIG. 4, wherein an oil-like surface additive supply plate 55 is positioned adjacent to the weir 21 so that the oil reservoir 56 is connected to the supply pipe 55 and It can be formed between the solder surface. Thin oil or other surface additive coatings are formed on the surface of the solder wave to reduce the surface tension and at the same time reduce the dross formation on the wave surface.

While embodiments of the various vanes are shown herein, it will be appreciated that the vanes are not necessarily located within the nozzle itself, but may be located within the solder flow between the nozzle outlet and the weir 21. The vanes may be located on the inlet side of the solder wave, indicated by the shake table 50 in FIGS. 4 and 5. There are no random parameters in the oscillation wave because the oscillation frequency and oscillation amplitude are precisely controlled. The shape or shape of the wings can be changed to apply vibration at a suitable location in the solder wave. Few places move or remove gas bubbles from under wiring board and reach all areas where solder is soldered

In one embodiment, the vibrator can produce frequencies in the range of 20 cycles / sec-400 cycles / sec, and can also vary vibration amplitudes of at least about 15 mm (0.060 inch). Higher frequencies may also be used. By using a vibrating mechanism showing a streamlined solder wave, the soldering quality of the wiring board is at least better than that of a soldering machine of two solder wave bands.

Various changes may be made to the embodiments shown herein without departing from the scope of the invention as defined by the following claims.

Claims (31)

Moving the pre-solvented member in a predetermined path; A solder wave having a mirrored shape is formed below the path to allow at least a portion of the member to pass through the solder wave, and about 20-400 Hz without substantially changing the predetermined shape of the solder wave in the solder band during the passage of the member. A pre-solvent treated out-of-member flow brazing method comprising steps of generating a vibration in a range. The pre-solvent printed wiring board or assembly is moved in a predetermined path, and a solder wave having a predetermined shape is formed below the path so that the lower part of the distribution board passes through the solder wave, and the solder wave band while the wiring board passes. A method of flow soldering of the surface mounting elements to a pre-solvent printed printed circuit board or assembly comprising the steps of generating a vibration at about 20-400 Hz, without substantially changing the predetermined shape of the solder wave. The method according to claim 1 or 2, wherein the frequency adjustment of the vibration is freed. The method according to claim 1 or 2, wherein the amplitude control of the vibration is freed. The method according to claim 1 or 2, wherein at least one shaking table is formed in the solder wave. The method according to claim 1 or 2, wherein a plurality of shake tables are formed in the solder wave. The method of claim 1 or 2, wherein the vibration is generated in a direction substantially parallel to the out-of-member path. The method of claim 1 or 2, wherein the vibration is generated in a direction substantially perpendicular to the out-of-member path. The method of claim 1 or 2 comprising applying a surface additive to the solder wave surface. Means for forming a solder wave having a predetermined shape, means for moving the pre-solvented member in a path so that at least a portion of the solder wave passes through the solder wave, and predetermined solder wave in the solder wave during the passage of the member. A pre-solvent-free out-flow soldering device comprising oscillating means for generating a vibration in the range of about 20-400 Hz without substantially changing the shape. Means for forming a solder wave having a predetermined shape, means for moving a pre-solvent printed wiring board or assembly in a path so that the lower portion of the wiring board passes through the solder wave, and the solder wave during the passage of the wiring board A device for flowing soldering of surface mount elements onto a pre-solvent printed wiring board or assembly, the oscillating means being configured to generate vibrations in the range of about 20-400 Hz without substantially changing the predetermined shape of the solder wave therein. An apparatus according to claim 10, wherein the oscillating means comprises at least one vibrating blade in the solder wave and at least one connecting rod connecting the vane to a vibrator means positioned away from the solder wave. 13. The apparatus of claim 12, wherein at least one vibrating blade in the form of a flat strip extends in the solder band substantially perpendicular to the out-of-member path, and wherein the vibrator means vibrates the flat strip in a direction substantially prone to the out-of-member path. 13. The apparatus of claim 12, wherein the plurality of vibrating vanes is recognized as a connecting rod and the vibrator means vibrates the vanes in a direction substantially perpendicular to the out-of-member path. 12. An apparatus according to claim 11, wherein the oscillating means comprises vibrator means and frequency adjusting means of vibrations from the vibrator means. The apparatus of claim 15, wherein the frequency can be varied in the range of about 20 cycles / second-400 cycles / second. An apparatus according to claim 11, wherein the oscillating means comprises a vibrator means and an amplitude adjusting means of vibration from the vibrator means. 18. The apparatus of claim 17, wherein the amplitude is adjusted to at least about 1.5 (0.060 inches). 13. The apparatus of claim 12, wherein the position of at least one vibrating blade in the solder wave is adjustable. 12. An apparatus according to claim 10 or 11 comprising means for supplying a surface additive to the solder wave. A reservoir adapted to receive the molten solder, a pump means for forming a solder wave having a predetermined shape from the nozzle located upwardly and directed upwardly, the nozzle, and a pre-solvent printed wiring board or Means for moving the assembly in the path so that the lower portion of the wiring board passes through the solder wave, and oscillating means for generating a vibration that does not substantially change the predetermined shape of the solder wave in the solder wave during the passage of the wiring board. A flow soldering device for surface-mounted elements in a pre-solvent printed wiring board or assembly example. 22. The apparatus of claim 21, wherein the oscillating means comprises at least one vibrating blade in the form of a flat strip extending to the discharge nozzle substantially perpendicular to the path of the distributing substrate and at least one connecting rod connecting the vane to the vibrator means. And a connecting rod extending in a direction substantially parallel to a path of the wiring board, wherein the vibrator means vibrates the vane in a direction substantially parallel to the path of the wiring board. 23. The apparatus of claim 22, wherein at least two shake tables are formed in the solder wave and one shake table is formed on each face of the blade. , 24. The apparatus according to claim 23, wherein at least one passive member is located in the solder wave downstream from the discharge nozzle at the outlet side of the wiring board and the position of the passive member is provided with another shaking table to help separate the wiring board from the solder wave. Providing device. 25. An apparatus according to Claim 24, comprising at least one liquid surface additive supply tube located downstream of the passive member, and means for supplying the liquid surface additive to the solder wave surface through the supply tube. A reservoir adapted to receive the solder at a predetermined level, a discharge nozzle positioned above the solder level in the reservoir and pointing upward and having a circuit board inlet side and a circuit board outlet side, and a predetermined form from the nozzle Means for contacting the bottom surface of the circuit board and forming a solder wave higher than any protruding metal surface, a circuit board path passing over the nozzle and inclined in the 욋 direction over the reservoir, and exiting from the inlet side of the nozzle Means for moving the circuit board in the path at a predetermined speed toward the side and oscillating means for generating vibration in the solder wave during the passage of the circuit board without substantially changing the predetermined shape of the solder wave. The nozzle is adapted to flow a larger volume portion of the solder wave downwardly from the inlet side. The inlet side of the nozzle has a bent downward induction device adapted to return the solder to a smooth flow into the reservoir, and the outlet side of the nozzle has an adjustable weir at the edge of the tray parallel to the side and the nozzle side It has a substantially longitudinal tray attached to it, the shape of the tray with its weirs, reducing the return of flow disturbances, and smoothly horizontally or downwardly at approximately the same speed and substantially the same direction as the circuit board traveling up the path. Apparatus for applying solder to a presolvent treated protruding metal surface and a presolvent exposed metal surface on one surface of a circuit board or the like, adapted to induce a residual volume portion of the solder wave in an oblique flow. 27. The device of claim 26, wherein a solder receiving zone is provided at the circuit board inlet side between the nozzle and the solder level of the reservoir and the adjustable induction means for changing the cross sectional area of the area between the adjustable induction means and the bent downward induction device. Device having. 27. The apparatus of claim 26, wherein the discharge nozzle has a vertical wall at the inlet side of the circuit board and an inwardly inclined wall at the outlet side. 27. The apparatus of claim 26, wherein the adjustable weir of the edge of the tray parallel to the outlet side of the nozzle is inclined inward at a maximum of 15 DEG to the vertical toward the discharge nozzle. 27. The apparatus of claim 26, wherein a deflector plate adapted to direct the solder into the reservoir is mounted below the adjustable weir. 27. The apparatus of claim 26, wherein at least one drain hole is installed in the longitudinal tray adjacent to the nozzle.

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