Method for containing a fluid volume in an inline conveyorized cleaner for cleaning low standoff components

Abstract

In one embodiment, the disclosed apparatus features a conveyor belt though an agitated reservoir of cleaning solution that is pooled by a flood box defined by sidewalls along the sides of the conveyor belt and opposing jets of water dubbed water curtains at the entrance and exit of the conveyor belt to and from the flood box, and, agitated by a plurality of spray nozzles shooting high flows of cleaning solution into the reservoir from above or within the flood box. The conveyor belt may be horizontal or slightly angled from the horizontal relative to the flood box.

Description

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

Printed circuit boards frequently have low-standoff components (i.e., components with low clearance from the board or other components) that are difficult to clean. This difficulty of cleaning low-standoff components arises because cleaning solutions, whether water or chemical based, cannot easily be provided to underneath the components. Although difficult, effective cleaning of circuit boards entails cleaning underneath any low-standoff components. Given the difficulty of cleaning low-standoff components a tradeoff exists between quick and effective cleaning of circuit boards.

This tradeoff can be illustrated with a comparison of two common cleaning methodologies, namely, spray and bath cleaning.

Spray cleaning involves passing circuit boards on a conveyor belt underneath spray nozzles of cleaning and rinsing solutions. Spray cleaning results in quick cleansing of circuit boards because many boards can be conveyed under the cleaner and rinse spray nozzles. However, at the same time, the sprayed cleaning solution usually does not provide enough force to overcome the surface tension under the low-standoff components to remove flux or other contaminants whereby spray cleaning is not effective.

Bath cleaning involves submerging a batch of circuit boards in a pool of cleaning solution, batch-by-batch. Bath cleaning, in contrast with spray cleaning, is effective because, over time, the cleaning solution is allowed to soak underneath the low-standoff components of the circuit board. Nonetheless, bath cleaning is not satisfactorily quick because soaking the circuit boards until underneath the low-standoff components is saturated with cleaning solution or rinse is a long process and, batch-by-batch circuit board cleaning is tedious.

In view of the foregoing, spray and bath cleaning methodologies and related apparatus are not entirely suited to cleaning circuit boards. In other words, a need exists for circuit board cleaning apparatus and related methods of use that are quick yet effective. Specifically, a need exists for apparatus and related methods of quickly cleaning circuit boards so that the entirety of any low-standoff components is cleaned.

SUMMARY OF THE INVENTION

An objective of this disclosure is to describe apparatus and related methods of quickly cleaning circuit boards, including underneath the boards' low-standoff components. In one embodiment, the disclosed apparatus features a conveyor belt through an agitated reservoir of cleaning solution that is

• (1) pooled by a flood box defined by
  • (a) sidewalls along the sides of the conveyor belt and
  • (b) opposing jets of water (dubbed water curtains) at the entrance and exit of the conveyor belt to and from the flood box; and,
• (2) agitated by a plurality of spray nozzles shooting high flows of cleaning solution into the reservoir from above or within the flood box. The conveyor belt may be horizontal or slightly angled from horizontal relative to the flood box.

In operation, circuit boards are provided to the agitated reservoir of cleaning solution via the conveyor belt. Suitably, the boards on the conveyor are submerged whereby the agitated solution can flood underneath the low standoff components.

BRIEF DESCRIPTION OF THE FIGURES

The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached figures in which:

FIG. 1 cross section of a flood box 1000;

FIG. 2 is a contextual view of the flood box of FIG. 1 disposed in a cleaning apparatus 2000;

FIG. 3 is a perspective view of the flood box 1000 inside a cleaning apparatus;

FIG. 4 is a contextual image of a circuit board passing through the flood box 1000; and

FIG. 5 is an image of a cleaning apparatus 2000 fitted with a flood box 1000.

It is to be noted, however, that the appended figures illustrate only typical embodiments of the disclosed apparatus and methods, and therefore, are not to be considered limiting of their scope, for the disclosed apparatus and methodologies may admit to other equally effective embodiments that will be appreciated by those reasonably skilled in the relevant arts. Also, figures are not necessarily made to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Generally described are apparatus and related methods of quickly cleaning circuit boards, including underneath any low-standoff components. In a preferred embodiment, the disclosed apparatus features a conveyor belt through an agitated reservoir of cleaning solution that is (1) pooled in a flood box defined by (a) a bottom pan positioned underneath the conveyor belt with opposing ends and sides, (b) sidewalls extending upward along the sides of the conveyor belt, and (c) opposing jets of water (dubbed water curtains) at the entrance and exit of the conveyor belt over each opposite ends of the pan; and, (2) agitated by a plurality of spray nozzles shooting powerful flows of cleaning solution into the reservoir from above or within the flood box pan. The conveyor belt may be horizontal or slightly angled from horizontal relative to the flood box. The more specific features of the disclosed apparatus are disclosed with reference to the figures.

FIG. 1 is a cross section of a preferred flood box 1000. As shown, the box features: a horizontal or slightly angled (±10 deg. relative to the horizontal), left-to-right conveyor belt 1100; a bottom pan 1100 with four walls, namely two side walls that extend upwardly past the conveyor belt and two ends that truncate just below the conveyor belt 1100; a left-to-right conveyor belt 1200 positioned above the pan 1100; to water jets 1300, one positioned above one end of the bottom pan and the other positioned above the other end of the bottom pan, said water jets 1300 configured to forcefully spray cleaning solution in the form of a curtain 1310 toward the center of the flood box 1000; a plurality of upper and lower lined spray nozzles 1400 spread out lengthwise along the conveyor belt and configured to spray cleaning solution into the flood box 1000; and a reservoir 4000 of cleaning solution that is disposed within the pan at a level that is above the conveyor belt and that is prevented from flooding over the ends via the curtain 1310. FIG. 2 is a contextual view of the flood box 1000 provided to within a cleaning apparatus 2000. FIG. 3 is a perspective view of the flood box 1000. It should be noted that ultra-sonics could be added to the flood box 1000 for enhanced cleaning.

Referring to FIGS. 1 through 3, the flood box generally operates by conveying circuit boards 3000 from left to right across the flood box 1000. Suitably, a reservoir 4000 of cleaning solution is provided to within the flood box 1000 (e.g., by spray nozzles 1320 at various intervals across the flood box 1000) to a level 4100 that is higher than the conveyor belt 1100. Suitably, the reservoir 4000 of cleaning solution is retained within the flood box 1000 without spilling out over the ends of the bottom pan 1200 (which ends are below the level 4100 of the reservoir) via the water curtains 1310, which are jets of water directed inward of the flood box 1000. In operation, circuit boards 3000 are placed on the conveyor belt 1100 and conveyed through the reservoir wherein the circuit boards are submerged in the reservoir 4000 upon passage through the entrance curtain 1310. Suitably, the reservoir 4000 is agitated by a plurality of spray nozzles or bars 1400 which spray water into the reservoir 4000. The agitated reservoir 4000 readily floods underneath any low-standoff components of the circuit boards 3000. FIG. 4 is a close up image of a circuit board 3000 that is submerged under the agitated reservoir 4000. Suitably, the length of the flood box can be calibrated or adjusted to accommodate various clean times or cleanliness standards.

It should be noted that a plurality of flood boxes 1000 can be positioned in series to accomplish various cleaning tasks. For instance, a series of three flood boxes 1000 may be constructed wherein the first flood box features a reservoir of preparation solution, second flood box features a reservoir of cleaning solution, and the third flood box features a reservoir of rinse solution. In other words, various processes can be accomplished via constructing several flood-boxes in series. An example of an apparatus with multiple flood boxes in series is provided as FIG. 5. In that figure, the cleaning flood box is blown-out in a circle.

In one mode of construction, a flood box may be fabricated by: first, adding water jets for water curtains at the entrance and exit ends of the conveyor belt; second, providing a bottom pan such that the conveyor passes through the ends and along the sides; third, adding spray bards above and below the fluid level inside the flood box; and fourth, providing a reservoir to within the flood box.

The disclosed apparatus may be constructed of any suitable materials and methodologies known for curcuit board cleaners. It should be noted that FIGS. 1 through 5 and the associated description are of illustrative importance only. In other words, the depiction and descriptions of the present disclosure should not be construed as limiting of the subject matter in this application. Additional modifications may become apparent to one skilled in the art after reading this disclosure.

Claims

1. A method of cleaning circuit boards comprising the steps of: confining a fluid cleaner between fluid curtains; and, submerging a cleaning circuit board in the confined fluid.

2. The method of claim 1 further comprising the step of: agitating the fluid while the circuit board is submerged.

3. The method of claim 2 wherein the fluid curtain is produced via a water knife.

4. The method of claim 3 wherein agitation of the fluid is accomplished via inline sprayers.

5. The method of claim 4 wherein the circuit board is submerged by passing a conveyor belt through the fluid curtains.

6. The method of claim 5 wherein the conveyor belt is passed through the fluid curtains horizontally.

7. The method of claim 5 wherein the conveyor belt is passed through the fluid curtains at an angle in the range of plus-or-minus ten degrees relative to the horizontal.

8. An apparatus comprising: a fluid reservoir confined between two curtains; and,an inline conveyor belt passing through two of said curtains and said confined reservoir.

9. The apparatus of claim 8 further wherein the reservoir is agitated.

10. The apparatus of claim 9 wherein the fluid curtain is produced via a water knife.

11. The apparatus of claim 10 wherein agitation of the fluid is accomplished via inline sprayers.

12. The apparatus of claim 8 wherein the circuit board is submerged by passing a conveyor belt through the fluid curtains.

13. The apparatus of claim 9 wherein the circuit board is submerged by passing a conveyor belt through the fluid curtains.

14. The apparatus of claim 10 wherein the circuit board is submerged by passing a conveyor belt through the fluid curtains

15. The apparatus of claim 12 wherein the conveyor belt is passed through the fluid curtains horizontally.

16. The apparatus of claim 13 wherein the conveyor belt is passed through the fluid curtains at an angle in the range of plus-or-minus ten degrees relative to the horizontal.

17. The apparatus of claim 14 wherein the conveyor belt is passed through the fluid curtains at an angle in the range of plus-or-minus ten degrees relative to the horizontal.

18. An apparatus comprising: a conveyor belt; and,a reservoir of cleaning solution that is(1) pooled by a flood box defined by (a) sidewalls along the sides of the conveyor belt and(b) opposing jets of water at the entrance and exit of the conveyor belt to and from the flood box, and,(2) agitated by a plurality of spray nozzles shooting high flows of cleaning solution into the reservoir from above or within the flood box; and,Wherein circuit board may be conveyed through a first of the jets of water and submerged within the reservoir prior to being conveyed through a second of the jets of water to exit the flood box.

19. The apparatus of claim 15 wherein the conveyor belt is horizontally oriented within the apparatus.

20. The apparatus of claim 1 wherein the conveyor belt is oriented within the apparatus at an angle of plus or minus 10 degrees relative to the horizontal.