Background of the Invention

In various wet processing art involving chemical treatment, such as etching, electroplating and the like, it is known to deliver fluids onto surfaces of articles being treated. In many instances, the articles being treated are printed circuit boards and the like. Often such articles are being delivered along a generally horizontal path and are etched, cleaned, rinsed, activated, dried, etc. , at various stations along the path.

Sometime the articles being treated, if they are printed circuit board, have bore holes extending therethrough and it is desired to have the treatment fluid impinge not only on upper and lower surfaces of the boards, but also on bore holes. The treatment of the articles can take place via nozzle arrangements, such as that set forth in U.S.

Patent No. 4,789,405, for example. In other instances the treatments may take the form various other fluid delivery, spraying, drying techniques, such as those disclosed in U.S. Patents 4,576,685, 4,017,982, 3,935,041, 3,905,827, or 3,776,800. Various drive techniques for driving the printed circuit boards or other articles through the various treatment stations may be used, such as those set forth in U.S. 4,046,248 or the like.

Accordingly, the technical field of this invention is directed to a method and arrangement for treating conductor substrates. Such treatment processes can include the removal of liquid from through holes in conductors boards and from its surface, drying the boards, in addition to cleaning, coating, rinsing, etching, activation and various electrolytic processes.

The present invention is directed toward efficient delivery of fluid to articles being treated, and most particularly to conductor boards and the like. In connection with the fluid delivery, slotted tubes, for example have been used, but such are limited in development of the flow upon exiting the orifice or slot, such that the flow stream may dissipate more quickly and lose some of its momentum, even expedientially, as the distance from the substrate being treated increases.

Spray nozzles are also use, but such often require large amounts of energy

relative to the fluid medium being processed. Additionally, in some instances spray nozzles do not provide the desired level of uniformity in terms of coverage, with a higher percentage of flow and pressure being located at the center of the nozzle spray pattem, and a lesser percentage of flow and pressure outwardly thereof, in that flow and pressure are often substantially reduced as the distance is increased perpendicular to the centerline of the nozzle.

Fluid jet injectors have also been used to produce tight columns of flow, but also generally fail to provide a desired level of uniform and complete coverage of the article being treated. Additionally, small injectors require substantially higher pressure to maintain a desired impact of force on the article being treated, which high force impact may always be desirable.

Summary of the Invention

The present invention provides a method and apparatus for delivering a fluid to printed circuit boards or other articles being treated, as the articles are delivered along a path of travel, by impinging the fluid on the articles from both sides of their path of travel. During such travel fluid is dispensed from nozzles and directed via the nozzles themselves and grooves that connect the nozzles, such that the fluid is provided in the form of a transverse extended screen-like fluid flow from the nozzle openings. The fluid delivered may be either liquid or gas. In the case of a liquid, the nozzle openings disseminate the flow into cylindrical filament-like columns of liquid flow, connected via the grooves into a generally flat transversely disposed planar screen spray of liquid. In the case of a gas fluid, such is provided via nozzle openings and transverse grooves connecting rows of openings, which openings are transversely spaced apart to facilitate disseminating from the openings via the grooves, transverse, planar zones of gas flow directed toward the path of article travel. Optionally, a suction effect may be created by an upstream-converging surface of the nozzle.

Various adjustments are provided for the apparatus in accordance with this invention. Additionally, various preferred parameters and structural arrangements are

utilized. In some case a row of nozzle openings is directed at an angle to the path of travel, aimed at the upstream direction of the path of travel.

Accordingly, it is a primary object of this invention to provide a novel method and apparatus for imparting fluid delivery to an article being conveyed along a predetermined path.

It is a further object of this invention to accomplish above object, wherein the fluid delivery is gas for drying an article, such as a conductor board.

It is another object of this invention to accomplish the primary object wherein the fluid is a liquid fluid delivery, such as for rinsing, etching, etc. Other objects and advantages will be readily understood upon a reading of the following brief description of the drawings, detailed description of the preferred embodiment and the appended claims.

Brief Description of the Drawing Figures

Fig. 1 is a longitudinal sectional schematic view, taken through a multi-station apparatus in accordance with this invention, wherein a plurality of etching, rinsing, drying operation are illustrated, and wherein means for imparting fluid delivery above and below articles such as circuit conductors, are illustrated.

Fig. 2 is a schematic, perspective view of a circuit board conductor being delivered along its path between upper and lower fluid dispenser manifolds in accordance with this invention, with the manifolds being of a type illustrated above and below the path of travel in Fig. 1.

Fig. 3 is an enlarged view of upper and lower fluid delivery manifolds as shown in Fig. 1 , with delivery plates thereof being shown in full lines close to the path of article travel, and in phantom lines spaced moreso from the path of articles travel.

Fig. 4 is a view taken generally along the line of IV-IV of Fig. 3, showing the lower end of a nozzle plate surface of an upper manifold fragmentally illustrated.

Fig. 5 is a longitudinal section taken generally along the line V-V of Fig. 4, wherein two generally perpendicularly disposed nozzles are illustrated, with an angled

nozzle being illustrated, disposed therebetween.

Fig. 5A is an enlarged detailed view of one of the nozzles and its associated groove illustrated in Fig. 5, wherein the geometric arrangement thereof is more clearly shown. Fig. 6 is a view similar to that of the liquid dispensing nozzle plate of Fig. 4, but with the nozzle plate of Fig. 6 being specifically adapted for gas dispensing, such as drying air or the like.

Fig. 7 is a longitudinal sectional view similar to that of Fig. 5 but taken generally along the line of VII- VII of Fig. 6. Fig. 8 is an enlarged fragmentary longitudinal sectional view taken through an alternative gas delivery pair of manifolds disposed on opposite sides of a path of travel of articles being treated, wherein the surfaces of the manifold plates closest to the path of travel are converging in an upstream direction to facilitate suction of fluid conveyed for impinging surfaces of articles being treated.

Detailed Descriptions of the Preferred Embodiments

Referring now to the drawings now in detail, reference is first made to Fig. 1, in which a fluid treatment system for articles being conveyed is generally designated by the numeral 10. In this embodiment, the articles being conveyed are printed circuit boards or the like 11, with through-holes such as 12 extending there through, with connecting portions 13 functioning as conductors along portions of the boards, as shown in Fig. 2.

In Fig. 1, a plurality of stations 14, 15 and 16 are illustrated, with station 14 functioning perhaps as an etching chamber wherein a suitable etchant may be dispensed onto appropriate surfaces of a printed circuit board or the like, followed perhaps by a rinsing station 15, in which the ecthant liquid (or other treatment fluid) would be rinsed from the articles 11 by means of fluid dispensers 17,18, followed by passage of the articles into another station 16, which may for example be a gas treatment station such as an air drying station wherein air is dispensed via dispensers 20,21 which, like the dispensers 17,18, are disposed on opposite sides of a path of

travel 22 for articles being conveyed through the apparatus of the system 10, as shown, from left to right, in the direction of the arrows 23.

Each of the stations 14-16 are provided with upper and lower walls, 24,25, side walls 26, inlet and outlet walls 27,28 with appropriate inlet and outlet openings 30,31, respectively.

The path 22 of travel of the articles 11 is therefore a longitudinal path of travel through the machine and in the embodiment shown, the path 22 is generally horizontal.

Appropriate drive rollers 32 are provided, generally shaft-mounted on transversely disposed shafts, which in turn are driven by any suitable means, such as a drive means for example as shown in U.S. Patent 4,015,706.

In instances particularly where the treatment fluid in a given station is liquid, such as for the station 15, and appropriate liquid discharge line 33 may be provided, for discharge to recycling or the like, as desired. With reference to Fig. 2, in particular, the article 11 is shown being delivered substantially horizontally in the direction of arrow 23, beneath a dispenser 17 and above a dispenser 18, it being understood that Fig. 2 could equally well represent dispensers 20,21 as desired.

With reference to Fig. 3, it will be seen that the upper dispenser 17 is disposed above the lower dispenser 18 for conveyance of articles 11 therebetween in a longitudinal, generally horizonal path of travel, as shown.

The dispenser 17 includes a manifold 35 which receives treatment liquid via a inlet tube 36 or the like, for delivery down through the manifold 35, through a manifold transition plate 37 having a large number of spaced apart transition holes 38 therein, arranged in a row, which extends transversely, substantially between sidewalls 26 of the apparatus as shown in dotted lines in Fig. 3. The fluid thus delivered via conduit 36 and manifold transition holes 38 is thus delivered to a multi- port fluid dispenser nozzle plate 40. The nozzle plate has a plurality of fluid dispenser nozzle openings 41, 42 and 43, arranged in transverse rows, perpendicular to the longitudinal path of travel 22 for articles 11 , and extending generally the

transverse length of the manifold 17, substantially completely between opposed sidewalls 26 of the apparatus.

A pair of article-engaging rollers 44,45 are provided, carried indirectly (by means not shown) by the manifold 17, respectively shaft-mounted at 46,47, to engage against an upper surface 48 of an article 11 being treated. The purpose of the upper and lower 44,45 is to resist the forces of impingement of fluid being delivered to an article 11 being treated via a manifold on the opposite side of the path of travel 22. Thus, fluid delivered via lower manifold 18 would impart an upward component of motion to the article 11 being treated as shown in Fig. 3, but for the resistance applied by the rollers 44,45 in engagement with an upper surface 48 of the article 11. Conversely, fluid delivered from upper manifold 47 onto an upper surface 48 of the article 11 , would be resisted by the presence of lower roller (unnumbered) carried by the manifold 18.

In order to accommodate different thicknesses of article 11, the manifolds 17,18, are vertically adjustable by any suitable means, such that their dispenser nozzle plates 40 may move, for example, between the full line positions therefor shown in Fig. 3, to the phantom line positions shown therefor, for accommodating, for example, a thicker article 11, while still maintaining a desired predetermined spacing between the surface of the plate 40 (for example the lower surface thereof as shown in Fig. 3) and the adjacent surface of the article 11 (for example, the upper surface 48 as shown in Fig. 3).

The means for adjusting the positions of the manifolds 17,18 toward and away from the path 22 of article travel can be any suitable means. A representative means is shown whereby an adjustable positionable member 50 is threadedly mounted through a fixed plate member 51, to support transversely extending posts 52 at opposite transverse ends of the manifold 17, whereby turning the treated member 50 may move the manifold 17 from the full line position shown for the post 52 in Fig. 3, to the phantom line position shown therefor also in Fig. 3, for movement of the plate 40 between the full line and phantom position described above. It will be understood that any suitable adjustment means may be provided for changing the relative

positions of the manifolds.

In the case where the path of travel 22 is a substantially horizontal path as shown, and wherein the rollers 44,45 for the upper manifold engage an upper surface 48 of articles 11 being treated, the weight of the rollers 44,45 may be used to provide the hold-down of the article 11 being treated in resisting upperwardly directly flow from the manifold 18. In such an instance, the shaft, 46,47 for the rollers 44,45, respectively may be mounted in vertical slotted holes 53,54, as shown.

Also, it will be noted, with reference to Fig. 4 that a plurality of spaced apart notches 55, spaced generally along the plates 40 between sidewalls 26, may accommodate rollers, 44,45, passing therethrough, as shown in Fig. 3, with clearance, so as not to engage portions of the plate 40 defined by the notches 55. Such allows close placement of the rollers 44,45 to the openings 41, 42 and 43 and similar openings on the opposite path of travel 22 in the manifold 18.