JPH06310836A - Dip soldering device for printed substrate - Google Patents

Abstract

PURPOSE:To avoid the adhering of an oxide to a soldered surface and the oxidation of the soldered surface due to the flowing of air knives by a method wherein, preceeding to the removal of any surplus solder by the air knives, a printed substrate is coated with a solvent for reducing the oxide on the surface of solder coated on the printed substrate. CONSTITUTION:Both surfaces of a printed substrate W are coated with solder by carrying the printed substrate W in a solder coating device for making the surface W pass through two solder coating chambers 10. At this time, a melted solder 2 runs in the intersecting direction to the carrier direction of the printed substrate W in respective solder coating chambers 10 thereby enabling the solder to be coated in even molten temperature. Besides, respective roller couples 11, 12 are lubricated with a solvent F to effectively reduce the oxide on the coating solder surface. Next, any surplus solder adhering to this printed substrate W is blown away by blowing hot blast using a pair of upper and lower air knives. Through these procedure, the solder surface can be lustered thereby enabling the roughness thereon to be smoothed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board dip-type soldering device used for applying solder to a wiring pattern of a printed circuit board (hereinafter simply referred to as a printed circuit board).

[0002]

2. Description of the Related Art Conventionally, oil film forming oil is supplied to the surface of a molten solder and a roller pair to prevent oxidation of the surface of the molten solder, and dirt such as solder oxide adheres to the surface of the roller pair. Techniques for preventing this are known. As a horizontal dip-type solder coating device of this type, one disclosed in, for example, Japanese Patent Laid-Open No. 2-148883 (FIGS. 4 and 5) has been conventionally known.

In the above-mentioned conventional example, as shown in FIGS. 4 to 5, for example, a solder storage tank 101 for storing molten solder 102.
A heat supply means (not shown) for maintaining the molten solder 102 in the solder storage tank 101 at a predetermined temperature; and two inner and outer solder baths 116 provided in the solder storage tank 101.
117, at least one solder coating chamber 110 that is provided in the inner solder bath 116 and that coats the molten solder 102 on both surfaces of the horizontally transported printed circuit board W, and supplies the molten solder 102 into the solder coating chamber 110. And a solder supply means 120.

Each of the solder coating chambers 110 has two pairs of roller pairs 111.
111, between the upper rollers 111a and 111a of the two roller pairs 111 and 111 before and after this, and the lower roller 111b.
The upper guide plate 113 and the lower guide plate 114, which are respectively provided between 111b, partition each other, and the molten solder 102 is supplied by the solder supply means 120 to fill the inside of the solder coating chamber 110 with the molten solder 102. ,
Molten solder 1 flowing out from the solder coating chamber 110
02 is returned to the solder reservoir 101, and the oil film forming oil Q is supplied to the surface of the molten solder.

In the above-mentioned conventional example, the oil film forming oil Q is directly supplied into the solder reservoir 101 to cover the surface of the molten solder, and each roller pair forming the solder coating chamber is connected to the surface level of the molten solder 102. It is configured to lubricate each roller pair with the oil film forming oil Q by immersing the roller pair in the lower part.

Further, in the above-mentioned conventional example, the molten solder 102 is in a high temperature idle state in which the solder supply means 120 is stopped.
The surface level of is at the high level H indicated by the phantom line,
When the inner and outer solder baths 116 and 117 are immersed below the surface of the molten solder 102, and when the solder supply means 120 operates at high temperature, the level of the surface of the molten solder 102 is at the low level L indicated by the solid line, Coating chamber 11
The molten solder 102 that has flowed out from 0 is inside solder bath 116.
To overflow into the outer solder bath 117, then overflow into the outer solder bath 117 and flow back into the outermost solder reservoir 101.

In this conventional example, the solder coating chamber 11
A solder supply port 125 is provided in the lower central part of 0 to form a flow of molten solder from the central part toward both ends. Reference numeral 130 in FIG. 4 is an oil supply means for supplying the oil film forming oil Q, and reference numeral 140 in FIG. 5 is a pair of upper and lower parts for blowing off excess solder adhering to the printed circuit board W carried out from the solder coating chamber 110. This is an air knife.

[0008]

In the above-mentioned conventional example, the oil film forming oil Q is supplied into the solder storage tank 101, and the oil film forming oil Q is sent to the solder coating chamber 110 together with the molten solder 102, and each roller pair 111 is supplied. However, it has the following drawbacks. In the solder storage tank 101, oxides of solder and the like float on the surface of the molten solder 102, and the oil film forming oil Q supplied into the solder storage tank 101 mixes with the oxides and becomes dirty. Then, each roller pair 111 is lubricated with oil Q, but dirt such as the oxide adheres to deteriorate the solder coating quality of the printed circuit board.

The oil film forming oil Q that lubricates each roller pair 111 prevents oxidation of the solder applied to the surface of the printed circuit board W. It cannot be removed. Moreover, the excess solder is removed by the air knife, but at this time, the solder surface applied to the printed board is oxidized by the blow of the air knife, the gloss of the solder surface is lost, and roughness is also generated to deteriorate the quality of the printed board. . The present invention takes such a situation into consideration, and improves the solder coating quality by preventing the above-mentioned adverse effects such as the oxide adhering to the solder surface of the printed circuit board and the solder surface being oxidized due to the blowing of the air knife. An object of the present invention is to provide a dip-type solder coating device for a punted substrate.

[0010]

In order to achieve the above object, the means adopted by the present invention are a solder coating chamber for storing molten solder, and a substrate dipping means for dipping a printed circuit board in the solder coating chamber. In a dip-type solder coating device for a printed circuit board, which comprises an air knife for removing the excess solder applied to the surface of the printed circuit board, prior to the removal of the excess solder by the air knife,
It is characterized in that a solvent is applied to the printed circuit board, and a solvent supply means for reducing the oxide on the surface of the solder applied to the printed circuit board is provided.

[0011]

[Operation] In the present invention, the solvent is applied to the printed circuit board by the attached solvent supply means. That is, the solvent is applied to the printed circuit board carried out from the solder application chamber prior to the removal of the excess solder by the air knife. This solvent reduces the oxide on the surface of the solder applied to the printed circuit board. Therefore, the oxide once attached to the solder surface of the printed circuit board W or the oxide formed by blowing the air knife is also removed by the reducing action of the solvent. As a result, the surface of the solder becomes glossy and the roughness is eliminated.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a dip-type solder coating device for a printed circuit board according to the present invention. FIG. 1 (A) is a vertical sectional front view of the solder coating device, and FIG. 1 (B) is a perspective view of a main part of a solder coating chamber.
2 is a plan view of the solder coating apparatus, and FIG. 3 is III in FIG.
It is a sectional view taken along the line III-III.

This solder coating apparatus has a solder reservoir 1 for storing molten solder 2, a heat supply means (heater) 3 additionally provided in the solder reservoir 1 for maintaining the molten solder 2 at a predetermined temperature, Two solder coating chambers 10 and 10 which are provided in the upper part of the solder storage tank 1 and which apply solder to both surfaces of the printed circuit board W which is horizontally conveyed, and the printed circuit board W are immersed in each solder coating chamber 10 and 10. The substrate dipping means 11 and 12, the solvent supplying means 30 for supplying the solvent F to the surface of the printed board W, and the pair of upper and lower air knives 40 for blowing off the excess solder on the printed board surface with hot air are provided.

Each of the solder coating chambers 10 has a pair of front and rear roller pairs (11a, 11a) which also serve as substrate dipping means 11, 12.
b) ・ (12a ・ 12b) and these two pairs of rollers (11a ・ 11
b). An upper guide plate 13 and a lower guide plate 14 provided laterally between the upper rollers 11a and 12a and between the lower rollers 11b and 12b of (12a and 12b), and each pair of these rollers (11a and 11b). 12a and 12b) are defined by the left and right chamber end walls 15 and 16 additionally provided at both ends in the axial direction. In each solder application chamber 10, the front and rear lower rollers 11b and 12b are positioned so as to be separated from the upper surface of the molten solder 2 stored in the solder storage tank 1. This is to prevent dirt such as oxides floating on the surface of the molten solder 2 in the solder storage tank 1 from adhering to each roller pair.

A solder supply port 26 is provided in each chamber end wall 15 of the left and right chamber end walls 15 and 16 constituting the solder coating chamber 10 and communicates with the solder discharge port 22 of the solder supply means 20. 25, and a solder outlet 27 is formed at the right end of the upper guide plate 13, and the molten solder 2 is supplied by the solder supply means 20 so that the inside of each solder application chamber 10 It is configured so that the molten solder 2 overflows from the solder outlet 27 of each solder application chamber 10 and is returned to the solder storage tank 1. The surface level of the molten solder 2 in the solder storage tank 1 is maintained at a substantially constant level by the overflow pipe 4.

In this way, when the flow of the molten solder 2 in the solder coating chamber 10 is made to intersect with the conveying direction of the printed circuit board W, the temperature of the molten solder 2 becomes uniform and the solder coating quality becomes good. Has the advantage that The solder supply means 20 includes a solder pressure pump 21 and
The pump drive motor 23, the transmission belt 24, and the communication chamber 25 are connected to the solder discharge port 22 of one solder pressure pump 21 in communication with the communication chamber 25, and each solder supply port of each solder application chamber 10 is connected. 26 is connected to the communication chamber 25.

In the above-mentioned embodiment, the two solder coating chambers 10 and 10 are arranged at the front and rear so as to be separated from each other, and the atmosphere discharge portion 10a is formed between them. This atmospheric emission unit 10a
Bubbles such as residual flux vapor generated on the lower surface of the printed circuit board W that is horizontally transported in the former solder coating chamber 10 are released to the atmosphere.
In general, even if solder is applied to both surfaces of the printed circuit board W within 0, and air bubbles are partially generated and left on the lower surface of the printed circuit board W, the atmosphere emission portion 10a
The air bubbles are released at this point, and then a perfect soldering process is performed in the subsequent solder coating chamber 10. This allows
Complete solder application is done.

At the left and right ends of the upper guide plate 13 of each of the solder coating chambers 10, the upper rollers 11a and 12 are provided.
The solvent fences 18 and 18 are horizontally provided so as to contact both end faces of a, and the solvent F is supplied from the solvent supply means 30 between the left and right solvent fences 18 and 18 on the upper guide plate 13. ing. In addition, the solvent fences 18 and 18 are horizontally provided at the left and right ends of the upper guide plate 13 so as to be in contact with the outer peripheral surfaces of both roller ends instead of being in contact with both end surfaces of the upper rollers 11a and 12a. Good.

The solvent supply means 30 comprises a solvent tank 31 for storing the solvent F and a pump 32 for supplying the solvent F. The solvent F supplied onto the upper guide plate 13 directly lubricates the front and rear two pairs of rollers 11 and 12, and is applied to the surface of the printed circuit board W through the pair of rollers 11 and 12. Then, the oxide on the solder surface is reduced. As the solvent F, an inorganic acid solution, a butyl cellosolve / polyalkylene glycol derivative, or the like is used. That is, the printed circuit board W discharged from the solder coating chamber 10
First, the solvent F is applied prior to the removal of the excess solder 2 by the air knife 40. The solvent F reduces the oxide on the surface of the solder applied to the printed circuit board W. Therefore, the oxide once attached to the solder surface of the printed circuit board W or the oxide formed by blowing the air knife 40 is also removed by the reducing action of the solvent F. As a result, the surface of the solder becomes glossy and the roughness is eliminated.

The operation of the apparatus of the above embodiment will be described below. First, the printed circuit board W subjected to the flux treatment is shown in FIG.
As shown by the arrow A, it is carried into the solder coating device. The solder is applied to both surfaces of the printed board W by passing through the two solder application chambers 10. At this time, the molten solder 2 flows in each solder application chamber 10 so as to intersect with the conveyance direction of the printed circuit board W, and the solder is applied at a uniform melting temperature. Also, each roller pair 11/12
Is lubricated with the solvent F supplied through the upper guide plate 13 to effectively reduce the oxide on the applied solder surface.

Next, hot air is blown toward the printed circuit board W carried out from the solder coating chamber 10 by a pair of upper and lower air knives 40 to blow off excess solder attached to the printed circuit board W. On the other hand, the molten solder 2 overflowing from each solder application chamber 10 flows into the solder reservoir 1 and flows back toward the pressure pump 21 as indicated by an arrow B in FIG. The printed circuit board carry-in roller 42 at the front stage and the printed circuit board carry-out roller 43 at the rear stage of the solder coating chamber 10 are arranged on both sides of the center part of the roller so that both right and left side portions of the printed circuit board W can be supported and conveyed in a point contact state. The diameter is gradually increased toward the portion.

In the above embodiment, the solvent F is supplied onto the upper guide plate 13 and the solvent F is applied to the surface of the printed circuit board W via the two front and rear pairs of rollers 11 and 12, but The upper guide plate 13 is not an essential component, and directly supplies the solvent F onto the molten solder stored in the solder application chamber 10 to apply the solvent F to the surface of the printed circuit board W via the roller pairs 11 and 12. You may do it. Further, in the above embodiment, the two solder application chambers 10 and 10 are spaced apart from each other in the front and back, but at least one solder application chamber is sufficient.

In the above-mentioned embodiment, the molten solder 2 is made to flow from one end side to the other end side of the solder coating chamber 10, but as in the conventional example, from the central portion of the solder coating chamber 10. You may make it flow toward both ends. Further, in the above embodiment, the horizontal dip type solder coating device is described, but instead of this, a vertical type dip type solder coating chamber is used, and the solvent F is directly supplied onto the molten solder stored in the solder coating chamber, The printed circuit board may be dipped in the solder coating chamber by a hanging type dipping means to coat the surface thereof with the solvent F and also to coat the solder. In this case, excess solder is removed with an air knife when the printed circuit board is pulled up. It should be noted that the other members can be implemented with appropriate changes.

[0024]

As is apparent from the above description, in the present invention, the solvent is supplied to the surface of the printed board to reduce the oxide on the solder surface prior to the removal of the excess solder by the air knife. The oxide once attached to the solder surface of the printed circuit board W or the oxide formed by blowing the air knife is also removed by the reducing action of the solvent, so that the solder surface has gloss and the roughness is eliminated. As a result, the solder coating quality of the printed circuit board is further improved.

[Brief description of drawings]

FIG. 1 shows a horizontal dip-type solder coating device for a pundt substrate according to an embodiment of the present invention, FIG. 1 (A) is a vertical sectional front view thereof, and FIG. 1 (B) is a perspective view of a main part of a solder coating chamber. is there.

FIG. 2 is a plan view of a horizontal dip type solder coating device for a pundt substrate according to an embodiment of the present invention.

3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a view corresponding to FIG. 1 of a conventional example.

FIG. 5 is a view corresponding to FIG. 3 of a conventional example.

[Explanation of symbols]

2 ... Molten solder, 10 ... Solder application chamber, 11.12 ... Substrate dipping means (roller pair), 30 ... Solvent supply means, 40 ... Air knife, F
… Solvent, W… Printed circuit board.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C23C 2/20 2/34

Claims (1)

[Claims] 1. A solder coating chamber for storing molten solder, a substrate dipping means for dipping a printed circuit board in the solder coating chamber, and an air knife for removing excess solder coated on the surface of the printed circuit board. In a printed circuit board dip-type solder coating device comprising: a solvent supply means for applying a solvent to the printed circuit board prior to the removal of the excess solder by the air knife, and reducing the oxide on the solder surface coated on the printed circuit board. A dip-type solder coating device for a printed circuit board, which is provided.