JP2886997B2 - Jet type soldering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Object of the invention]

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet type soldering apparatus.

[0003]

2. Description of the Related Art As shown in Japanese Patent Application Laid-Open No. 63-43761, a hollow drum having a large number of solder ejection holes formed at an upper end ejection nozzle of a nozzle provided in a solder bath is rotatable. There is a jet type soldering apparatus which forms a large number of projecting jet waves by jetting molten solder through a solder jet hole of the hollow drum provided.

In this apparatus, flux gas and the like are expelled from minute gaps of chip components mounted at high density on a printed wiring board as a work by rotating a hollow drum to give a turbulent jet flow. There is an advantage that the solder wettability of this high-density mounting board can be improved.

[0005] Such a turbulent projecting jet wave is called a primary solder wave, and soldering utilizing this primary solder wave is called primary soldering, and is further used for this primary soldering. The nozzle is called a primary nozzle and has been confirmed to be effective in soldering a chip component mounting board.

On the other hand, when the primary soldering is performed by the primary solder wave jetted from the primary nozzle, a soldering defect in which the solder hangs in an "icicle" shape or a "bridge" that short-circuits the electrodes of the chip component occurs. There is a disadvantage that soldering failure is easily generated.

Therefore, conventionally, a secondary solder bath 11 as shown in FIG. 7 or FIG. 8 is continuously arranged after a primary solder bath provided with the primary nozzle, and the primary solder wave having the disturbance is used. Immediately after performing the primary soldering, the secondary solder wave 13 that is smoothly jetted from the secondary nozzle 12 provided in the secondary solder bath 11 performs quiet secondary soldering, thereby mounting chip components. The primary soldering portion of the substrate W is shaped to eliminate the above-described soldering failure such as a bridge.

In this conventional secondary nozzle 12, as shown in FIG. 7 or 8, a secondary solder wave 13 which jets from a jet port 14 and flows down to a molten solder surface 15 in a secondary solder bath 11 by natural force. On the other hand, when soldering is performed while the component mounting board W is transported in the upwardly inclined shape by the transport conveyor 16 inclined in the direction of rising by 3 to 7 °, the primary soldering portion is effectively shaped by the counter solder flow, It is known that good secondary soldering results can be obtained.

[0009]

However, when the conveyor 16 is inclined at an angle of 3 to 7 degrees as described above,
The difference between the heights of the transfer lines located before and after the solder bath 11 becomes large, and it is necessary to provide a lifting lifter or the like to match the transfer lines having different heights. In addition, since it is important for the conventional secondary nozzle 12 to optimally select the rising inclination angle of the transport conveyor 16, the frequency of variably adjusting the conveyor angle is often increased, and the height of the nozzle or the like is adjusted each time. There are drawbacks that must be done.

On the other hand, in the conventional secondary nozzle 12, since the upper surface of the secondary solder wave 13 is planar, if the conveying conveyor angle is made closer to horizontal (0 to 3 °), as shown in FIG. The position at which the substrate W separates from the secondary solder wave 13 is A
To the substrate unloading side from B to B, and at the departure position B,
There is a disadvantage that the flow velocity of the jet solder is not the optimal one set at the initial detachment position A (the opposed flow velocity decreases), and soldering failure such as a bridge failure easily occurs. further,
In such a case, the position where the secondary solder wave 13 separates from the substrate W tends to be unstable due to a slight change in the wave height of the secondary solder wave 13, and the soldering such as a bridge failure is also considered from this point. Failure is likely to occur.

The present invention has been made in view of such a point, and even when a work is conveyed in a horizontal or close state, the detached position between the work and the secondary solder wave can be stabilized at the position of the optimum flow velocity. It is another object of the present invention to provide a jet-type soldering apparatus capable of preventing occurrence of a soldering failure such as a bridge failure.

[Structure of the Invention]

[0013]

According to a first aspect of the present invention, there is provided a jet-type soldering apparatus for jetting molten solder from a nozzle 12 provided in a solder bath 11 to perform soldering on a work W. A drum 24 laid horizontally above the nozzle 12, a molten solder rising passage 31 provided along the outer peripheral surface 24a of the drum 24 on the work discharge side, and a continuous flow from the molten solder rising passage 31 to the work loading side. And an arc-shaped guide surface 33 provided on the upper surface of the drum to form a jet solder surface in an arc shape.

According to a second aspect of the present invention, in the jet type soldering apparatus of the first aspect, a driving mechanism 26 for rotating the drum 24 in the forward direction with respect to the jet solder rising direction and in the reverse direction with respect to the workpiece transfer direction, The drum 24 has concave portions 51 and convex portions 52 provided alternately on the outer peripheral surface of the drum 24.

According to a third aspect of the present invention, in the jet type soldering apparatus of the second aspect, the concave portion 51 and the convex portion 52 on the outer peripheral surface of the drum are provided to be inclined with respect to the drum axis.

The invention according to claim 4 is the invention according to claim 2 or 3.
In the jet type soldering apparatus of the above, the drum 24 is provided so as to be adjustable in speed.

[0017]

According to the first aspect of the present invention, the molten solder to be jetted from the nozzle 12 is applied to the outer peripheral surface 24 of the work carrying side of the drum 24.
a, and the arc-shaped guide surface on the top of the drum
Since the solder flows on the work loading side (in the direction opposite to the work advancing direction) along 33, the jet solder surface rises in an arc shape along the drum curved surface above the arc-shaped guide surface 33, and a constant flow velocity flows to the work loading side. Smooth arc-shaped raised solder surface S
To form Since the work W passes on such a raised solder surface, even if the work W is conveyed horizontally or in a state close thereto, the work W separates from the raised solder surface S at a predetermined position P, and at the same time, the separated position. At P, the jet solder is flowing at a constant speed.

According to a second aspect of the present invention, the driving mechanism 26 rotates the drum 24 in the direction opposite to the work transfer direction, and the concave portion 51 and the convex portion 52 on the outer peripheral surface of the drum allow the molten solder flow facing the work W to move relative to the workpiece W. Increase speed.

According to the third aspect of the present invention, the molten solder is jetted from obliquely forward to the work W by the concave portion 51 and the convex portion 52 inclined with respect to the drum axis.

According to a fourth aspect of the present invention, the molten solder is caused to flow at a speed suitable for various types of workpieces by adjusting the rotational speed of the drum 24 according to the conditions of the workpiece W.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to various embodiments shown in FIGS. Note that, even in different embodiments, similar parts are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 1, a pump (not shown) and a secondary nozzle 12 communicating with the discharge side of the pump are provided inside a secondary solder tank 11 disposed after a primary solder tank (not shown). A drum case 23 is attached to an upper end of the secondary nozzle 12, and a drum 24 is provided horizontally above the secondary nozzle 12 inside the drum case 23.

In the drum 24, a drum shaft 25 integrally formed on both end surfaces of the drum main body is rotatably fitted to a side plate of a drum case 23 and is rotatably supported. A driving mechanism 26 for rotating the drum is provided for the drum 24.

The driving mechanism 26 has a large-diameter gear 27 concentrically and integrally attached to one side surface of the drum 24.
The small-diameter gear 29 integral with the rotating shaft 28 meshes. The rotation shaft 28 is
It is rotatably held by a bearing (not shown) attached to a side plate (not shown) of the drum case 23, and is driven by a variable speed motor (not shown) provided outside the solder bath 11 via a transmission mechanism (not shown). By using the variable speed motor as the drive source in this way, the rotation speed of the drum 24 can be adjusted.

A transport conveyor is provided above the drum case 23.
16 is provided almost horizontally. As is well known in the art, the conveyor 16 engages and transfers a work (chip component mounting substrate) W between a pair of endless chains that are rotated synchronously.

The drum case 23 has a work carrying side portion 23.
a is formed in a bulging shape, and a molten solder rising passage 31 is provided inside the work discharge side portion 23a along the outer peripheral surface 24a of the drum 24 on the work discharge side.

An arcuate guide surface 33 is provided on the upper surface of the drum which is continuous from the molten solder ascending passage 31 to the work loading side, and which raises the jet solder surface in an arc shape.

The work discharge side 23a of the drum case 23
The guide plate 34 is fixed to the upper end of the case by screws 36 screwed to the upper end of the case through the elongated holes 35 of the guide plate 34. Said slot 35
Are elongated in the drum circumferential direction, so the guide plate 34
Can be moved and adjusted in the circumferential direction of the drum. Thereby, the position of the upper end opening 37 of the molten solder rising passage 31 can be adjusted.

Similarly, the work loading side of the drum case 23
A substantially L-shaped guide plate 41 is fixed to the upper end of 23b by a screw 43 screwed to the upper end of the case through an elongated hole 42 of the guide plate 41. Since the elongated hole 42 is formed in the up-down direction, the mounting position of the guide plate 41 can be adjusted in the up-down direction. By this adjustment, the tip 44 of the guide plate 41 is brought as close as possible to the drum peripheral surface, so that the molten solder flowing on the guide plate 41 from the arc-shaped guide surface 33 is smoothly guided, and the nozzle 12 The guide plate 41 prevents the flow of the molten solder that is going to rise to the upper surface of the drum along the outer peripheral surface 24b on the work loading side.

Next, the operation of the embodiment shown in FIG. 1 will be described.

The molten solder contained in the secondary solder tank 11 is pumped to the secondary nozzle 12 by a pump (not shown) provided in the tank. The molten solder that is about to flow from the secondary nozzle 12 rises along the outer peripheral surface 24a on the work unloading side of the drum 24, and further moves along the arc-shaped guide surface 33 on the upper surface of the drum 24 (the work advancing direction). (In a direction opposite to the direction opposite to the above), and circulates through the upper surface of the work carrying-side guide plate 41 to the molten solder surface 15 in the bath.

As described above, the solder surface jetted onto the drum rises in an arc shape along the drum curved surface of the arc-shaped guide surface 33 to form a smooth raised solder surface S having a constant flow rate toward the work loading side. I do. The work W enters from the opposite side so as to come into contact with the raised solder surface S, and the work W
And the chip component adhered to the substrate are soldered.

At this time, even if the work W is conveyed horizontally or in a state close to it (0 to 3 °), the work W separates from the raised solder surface S at a predetermined position P, and at the separated position P, the jet solder Flows at a constant flow rate.

The above-described arc-shaped raised solder surface S along the drum curved surface is basically obtained without stopping the driving mechanism 26 and rotating the drum 24.

On the other hand, when the driving mechanism 26 drives the drum 24 to rotate in the forward direction with respect to the jet solder rising direction and in the reverse direction with respect to the work transport direction as shown in FIG. , Raised solder surface S
In this case, the relative speed of the molten solder flow facing the workpiece transfer direction can be increased. At that time, by controlling the variable speed motor of the drive mechanism 26 to adjust the rotation speed of the drum 24, the speed of the molten solder flow on the raised solder surface S can also be controlled, and the molten solder can be formed at a speed suitable for various workpieces. Can be spouted.

Next, as shown in FIGS. 2 and 3,
If concave portions 51 and convex portions 52 parallel to the drum shaft 25 are provided alternately on the outer peripheral surface of the drum 24, the concave portions 51 and convex portions 52 are formed when the driving mechanism 26 rotates the drum 24.
Therefore, since the molten solder entrainment action becomes remarkable, there is an advantage that the speed of the molten solder flow on the raised solder surface S can be easily controlled.

As shown in FIGS. 2 and 3, one side of the drum 24 is provided with a boss 53 for fitting the large-diameter gear 27 and a screw for fixing the large-diameter gear 27 with screws. Screw holes
54 are provided.

Next, as shown in FIGS. 4 and 5,
A concave portion inclined on the outer peripheral surface of the drum 24 with respect to the drum axis.
The projections 51 and the projections 52 may be provided alternately.

As described above, the recess 51 is inclined with respect to the drum shaft.
In the case where the convex portion 52 is provided, a molten solder flow can be formed obliquely facing the work W from the front as shown in FIG. However, the same effect can be obtained as in the case where the angle is not oblique.

That is, as shown in FIG. 6, (A) when a secondary solder flow is opposed from the front to a work such as a QFP component having leads on four sides, the secondary There is a possibility that a contact portion a where the solder flow cannot flow around may occur, and a bridge may remain at the end contact portion a. However, (B) when the solder flow is opposed from diagonally forward, There is an advantage that the contact portion a is unlikely to occur. This is the same for other chip components.

[0041]

According to the first aspect of the present invention, a smooth raised solder surface having a constant flow velocity toward the work carrying side can be formed using the outer peripheral surface of the drum. Even if the work is transported in this state, the work can be separated from the raised solder surface at a fixed position, and the separated position is stabilized, and the solder flow rate at the separated position becomes a constant speed in the direction opposite to the work traveling direction. Insufficient soldering such as the occurrence of bridges in the next soldering can be prevented. In addition, since the work can be transported horizontally or in a state close thereto, the height of the transfer lines located before and after the solder bath can be made the same or close to that, and further, the work can be horizontally transferred. There is little need to change the conveyor angle, and there is also an advantage that the height adjustment of the nozzles and the like accompanying the change of the conveyor angle is not required or can be finely adjusted.

According to the second aspect of the present invention, the drum having the concave portion and the convex portion on the outer peripheral surface is rotated in the direction opposite to the workpiece conveying direction by the driving mechanism, and thus the molten solder is caused to rotate by the concave portion and the convex portion. , The molten solder flow can be given a sufficient relative speed to face the workpiece,
It is effective in preventing soldering defects such as bridges in secondary soldering.

According to the third aspect of the present invention, the molten solder is jetted obliquely forward from the workpiece by the concave and convex portions inclined with respect to the drum axis. The device structure can be simpler than when the nozzles are arranged in a plane with respect to the workpiece transfer direction.
Space saving can be achieved.

According to the fourth aspect of the present invention, the rotational speed of the drum is adjusted in accordance with the condition of the work, whereby
The flow velocity of the solder at the workpiece detaching position can be controlled to a speed suitable for various workpieces, which also helps to reduce soldering defects such as bridges.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a jet type soldering apparatus of the present invention.

FIG. 2 is a sectional view showing an example of a drum used in the jet-type soldering apparatus.

FIG. 3 is a side view of one half of the drum shown in FIG. 2;

FIG. 4 is a sectional view showing another example of the drum.

FIG. 5 is a side view of one half of the drum shown in FIG.

FIG. 6 is an explanatory diagram showing an effect of the embodiment shown in FIGS. 4 and 5;

FIG. 7 is a cross-sectional view showing an example of a conventional jet type soldering apparatus.

FIG. 8 is a sectional view showing another example of a conventional jet-type soldering apparatus.

[Explanation of symbols]

 W Work 11 Solder tank 12 Nozzle 24 Drum 24a Outer peripheral surface of work unloading side 26 Drive mechanism 31 Melted solder rise passage 33 Arc guide surface 51 Concave 52 Convex

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Junichi Onozaki 1-19-43 Higashi-Oizumi, Nerima-ku, Tokyo Inside the Tamura Corporation (56) References JP-A-59-163070 (JP, A) JP-A 63-80962 (JP, A) Fully open Showa 61-41458 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B23K 1/08 320 B23K 3/06 H05K 3/34 506

Claims (4)

(57) [Claims] 1. A jet-flow soldering apparatus for jetting molten solder from a nozzle provided in a solder bath to perform soldering on a work, wherein a drum provided laterally above the nozzle and a work of the drum are provided. It has a molten solder rising passage provided along the outer peripheral surface on the carry-out side, and an arc-shaped guide surface provided on the upper surface of the drum which is continuous from the molten solder rising passage to the work carry-in side and which raises a jet solder surface in an arc shape. A jet type soldering machine characterized by the following. 2. A drive mechanism for rotating a drum in a forward direction with respect to a jet solder rising direction and a reverse direction with respect to a work transfer direction, and a concave portion and a convex portion provided alternately on an outer peripheral surface of the drum. The jet type soldering apparatus according to claim 1, wherein: 3. The jet type soldering apparatus according to claim 2, wherein the concave and convex portions on the outer peripheral surface of the drum are provided to be inclined with respect to the drum axis. 4. The jet type soldering apparatus according to claim 2, wherein the drum is provided so as to be adjustable in speed.