CA2017286A1

CA2017286A1 - Apparatus for processing and/or cleaning articles, in particular circuit boards incorporating drillings, or drilled holes, with the aid of a liquid that is applied in a surge

Info

Publication number: CA2017286A1
Application number: CA002017286A
Authority: CA
Inventors: Manfred Kallweit; Horst Blasing
Original assignee: Individual
Current assignee: Bayer Pharma AG
Priority date: 1989-05-23
Filing date: 1990-05-23
Publication date: 1990-11-23
Also published as: DE3916694A1; JPH03101880A; KR900018416A; EP0456870A1

Abstract

ABSTRACT OF THE DISCLOSURE

A system is disclosed for processing and/or cleaning articles, in particular circuit boards that incorporate drillings, with the help of a liquid that is applied in a surge. In order to increase, enhance or supplement the action of the surge flow, on one side of the articles that are to be cleaned or processed there is a surge section and on the other side of the articles there is a suction section.
In addition, a process is disclosed for adjusting the ratio of the quantity of liquid that is delivered through the particular surge section relative to the quantity of liquid that is drawn off through the particular suction section.

Description

~7~

The present invention relates to an apparatus for processing and/or cleaning articles, in particular circuit boards incorporating drillings or drilled holes, with the aid of a liquid that is applied in a surge.

Cleaning or processing of this kind, that is effected by means of a surge ~low with a suitable liquid, is described in DE-PS 30 11 061 and in DE-OS 35 28 575. DE-PS 30 îl 061 describes the application of a surge flow to the article from below, whereas DE-OS 35 28 575 describes a process that is effected either with the lower surge nozzles alone or, in the case of cleaning processes that use ultrasound and - electrochemical processes, two surge nozzles that are in each instance o~fset on the upper and lower sides of the circuit board. The processes that are described in the above-cited pre-publications, and the systems, have proved to be ; satisfactory in principle although they do not satisfy all the demands imposed upon them in practice.

It is an object of the present invention to provide an apparatus that permits the effect of the surge flow to be amplified or supplemented.

According to the present invention there is provided a system for processing and/or cleaning articles, in particular circuit boards incorporating drillings or drilled holes, with the help of a liquid that is applied in a surge, wherein on one side of the article that is to be cleaned or processed there is a surge section and on the other side of the article there is a suction section.

The suction section increases the action of the surge section, since the force of the suction acts in the same direction as the surge flow. This results in a combined effect.

:

In a preferred embodiment, the suction force works directly on the surge flow that passes from the surge section through the drillings in the articles that are to be processed or cleaned. The suction force of the suction section preferably acts after a specific time delay such that any residual liquid that is left behind in the drillings incorporated in the articles to be processed or cleaned is sucked out. This arrangement is recommended in particular if the liquid is a processing liquid, e.g. an acid, whereas the above embodiment provides for the direct acceleration or amplification of the surge flow.

In an embodiment that is particularly advantageous with regard to its combined action, one group transports the liquid downwards from above and the other group conducts the liquid upwards from below through the drilled holes incorporated in the article that is to be processed or cleaned. A particularly intensive cleaning and processing is achieved by this means.

As has been indicated in the literature cited heretofore, a surge is understood to be a continuously flowing column of liquid or stream of liquid that emerges from the surge section and strikes the articles that are to ba cleaned or processed in this form, whereas, in contrast to this, known spray or sprinkler systems apply a sprayed or atomized processing liquid, which is thus mixed with air, against the articles to be processed. In contrast to thisj the principal advantage of such a surge flow is that it passes liquid through existing drillings very vigorously and thus cleans these much more completely than i5 possible if this process is carried out by spraying or sprinkling with liquid.

In addition to the surge flow, it is desirable to create an accumulation of cleaning or processing liquid. Here, in addition to the kinetic energy of the surge flow, the weight of this liquid also acts on the article. Both supplement 2 ~ ~. r~

each other. In this combination of such an accumulation with a surge section that is arranged above the article to be processed, one advantage is that the surge section takes up a specific space in the accumulation area so that a smaller quantity of liquid has to be built up in order to achieve a specific height of the level o~ the liquid. This means that less pumping power is required.

The effect of the cleaning of the article that is to be processed, and in particular the cleaning of drilled holes or drillings, is enhanced with the above-discussed features.
This is of particular interest with respect to circuit boards used for electronic equipment, for these incorporate relatively small drillings that require particularly intensive cleaning and flushing. In addition, a specific reservoir of liguid is created with the accumulation of liquid within the surge section, and this is an advantage if the supply of liquid has to be reduced or even interrupted for a brief time, for some reason or another. In addition, the section above which the processing liquid can operate on the article is extended by this accumulation. This is also advantageous if the most intensive action takes place ~irst in the surge chambar.

In an embodiment of the accumulation means that is of simple design and effective i~ operation, the s~ueeze rollers rotate with the article that is to be processed that lies on them and passes through them, so that any injurious friction between the accumulation means and the article to be processed is avoided.

A further advantageous embodiment is particularly suitable for cleaning blind holes or drillings in the panel-like articles.

In a still further embodiment an even distribution and outflow cross-section of the liquid surge is provided across the whole width of the article that is to be processed.
Although such an arrangement is known per se from DE-OS 35 28 575, this is not so, however, in conjunction with an arrangement according to one or more of the claims described heretofore.

The various configuration possibilities that apply to the present invention can be combined with each other.

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:-Figure 1: is a plan view of a system according to the presentinvention, wherein the left-hand half of the drawing shows the embodiment according to figure 2 and the right-hand half of the drawing shows the embodiment according to figure 3;

Figure 2: is the above-discussed first embodiment of the present invention in cross-section on ths line II-II in figure l;

Figure 3: is the above-discussed second embodiment of the present invention in cross-section on the line III-III in figure 1;

Figure 4: is a further embodiment shown diagrammatically in sîde view with the associated schematic diagram for the flow of liquid.

Figure 1 is a diagrammatic plan view of a part 1 of a galvanic system with a plurality of cleaning or processing sections 2, 3, a suitable number of which are combined one after the other in the direction indicated by the arrow 4.
The articles to be cleaned or processed, in this instance, the boards 5, in particular circuit hoards for elactronic 2~ 7~

purposes, are moved in the direction indicated by the arrow 6.

The embodiment that is shown in figure 2 shows the above-discussed section 2, the article 5 being viewed from the narrow side edge. This incorporates drillings 7 which, for purposes of simplicity of illustration, are only shown in the area of the section. The articles can be moved by means of conveyor rollers (not shown herein). The applicat~on of the liquid to the articles 5 is effected by means of a surge section 8 that incorporates a housing 8', to which the liquid is supplied through the lines 9. The length L of the surge section can be seen in figure 1. It extends across the whole width of the part 1, so that the articles 5 can be cleaned or processed across its total width B. The liquid enters the surge chamber 12 through a slot 11 that also extends to the whole length L. An accumulation 14 of liquid can be built up on both sides of the side wall of the housing ~' by squeeze rollers 13 that are arranged at the inlet and the outlet of the surge section. As has already been discussed, this extends the section along which the processing fluid can act on th~ articles. The flow surge passes into the housing 17 of the suction section 10 after passing through the drillings 16 in the articles 5, where it is drawn off through the line 18. The proportion of the quantity of liquid that is delivered through the surg~ section 8 to the quantity of liquid that is drawn off through the suction section 10 can be adjusted in order to achieve the best effect in each particular case. In particular, it can be advantageous to draw off more liquid per unit time than is supplied. In this case, a jet of liquid through the drillings 16 does not impact directly on a liquid and the partial vacuum that is ef~ective in the suction section 10 enhances the passage of the liquid through the drillings 16. The squeeze rollers 13 that extend across to the whole length L are supported so as to be rotatable, so that there is no friction between them and the article that lies on them and moves in the direction .

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indicated by the arrow 6. There are counter-rollers 19 associated with the rollers 13. The rollers 13, 19 can also fulfill a conveying function. Optionally, it could also be possible to provide separate conveyor rollers (not shown herein) which are preferably not continuous, as is the case with the squeeze rollers and the counter-pressure rollers, but which consist of individual disk-shaped roller sections.

In this embodiment, the suction section 10 is directly opposite the surge section 8. However, it could also be displaced in the direction of movement of the articles (as shown by the dashed line 10'). In the case of a surge section 8 that is provided above the articles, as in this embodiment, to provide two suction sections on the underside of the articles, namely one, as indicated by the figure 10, directly opposite the suction section 8 and a further one, as indicated by 10', which i5 displaced in the above sense.
Which of the above-described variations is used in practice will depend on the type of article and in particular the drillings that are to be processed or cleaned and also on whether this process is carried on in a processing station or a cleaning station.

Figure 3 shows in principle the same arrangement as in figure 2, namely a surge section 20 that is arranged above the articles 5, a suction section 10 that is directly opposite this and/or a suction section 10' that is displaced in the direction of movement 6 and which is also located beneath the articles. Unlike the embodiment shown in figure 2, here the liquid, e.g. pure water, i5 delivered via a series of ~eed lines 21 of larger diameter within the housing 22 of the surge section 20 to a pre-chamber 23 that extends for all practical purposes to the whole length L of the housing 22 of the surge section. From there, the liquid moves through two or more series of drillings 24 that are of smaller diameter (relative to the diameter of the feed lines 21) into a distributor chamber 25. The drillings 24 are also provided, 2 ~ ~ 7 ~

arranged one after the other, to the whole length L. The number of drillings 24 of smaller diameter acts like a perforated mask. When the liquid passes from the pre-chamber 23 into the distributor chamber 25 there is a specific pressure drop in the liquid and simultaneously an even distribution of the liquid through the perforated mask within the distributor chamber 25 to the whole length L. This means that the liquid emerges from the slot-shaped surge opening 26, which also extends to the whole length L, in an even surge and distributes itself into the surge chamber 27, to emerge from there through the drillings 16 in the article, after which, as indicated by the arrows 18, it moves downwards into the housing 28 of the suction section 10.
From there, it is drawn o~f through the line 18. Reference is made to the preceding embodiments with regard to the suction section 10 and/or the use o~ the suction section 10'.
Squeeze rollers (not illustrated herein) can also be used to create a liquid accumulation or bed as shown at reference 14.
The drillings 24 are displaced relative to the supply lines 21 in the direction of movement 6, so that the liquid does not move in a straight line from the feed lines 21 through a drilling 24 to the slot-like opening 26. There is also a corresponding displacement of the drillings 24 relative to the slot-shaped opening 26.

The arrangement of the surge section and the suction section can also be reversed, i.e., the surge section or sections, respectively, can be located beneath the path of the articles and the suction section or sections can be located above this path. With reference to the embodiment shown in figures 2 and 3, this is not shown in a separate illustration.

In the embodiment shown in figure 4, there are two gr~ups, consisting of a surge section 8 and a suction section ln adjacent to each other, wherein in one group (in this example this is the first group to be processed in the direction o~
movement of the articles3 the surge section 8 is below and 2 ~ f,i~ ~ iJ

the suction section 10 is above the path of the articles, whereas the other group that is adjacent to this is arranged such that the sur~e section 8 is above and the suction section 10 is below the axticles.

This means that the articles to be processed, i.e., the drillings in these articles, are flushed one after the other from below upwards and immediately thereafter from above downwards and thus exposed to a more intensive cleaning or processing. Here, too, squeeze rollers 13 and corresponding 10 counter-rollers 13' can be provided; for reasons of simplification of the illustrations, only the first such pairs are shown herein. Conveyor rollers can also be provided, although for reasons of simplification of the illustrations, these are not shown herein, or the conveyor 15 function can be assumed by the rollers 13, 13'. This is the preferred embodiment of the present invention.

In the left-hand section, which also shows the squeeze rollers 13, figure 4 shows that in addition to the surge flows indicated by the vertical arrows 28 it is also possible 20 to generate flows that branch off approximately horizontally from the corresponding vertical flows, as indicated by the arrow 29'. To this end, all that is required is that the middle partition 30 between the two groups does not extend down to the articles 5, an intermediate space for the flows 25 29' is left at thi3 location. These flows 29' flush out the blind holes or blind drillings that are not cleaned, or are only incompletely cleaned, by the vertical flows. It will depend on the dimensions of the flow cross-sections whether one makes the vertical or the horizontal flows the most 30 powerful. In this arrangement according to the present invention, it is recommended that the squeeze rollers 13 be as close as possible to the housing o~ these groups in order that the horizontal flows cannot escape upwards between the squeeze rollers and the housing of the particular group.

2 ~ ~ i f ~ ~ ~

The centre pair of components and the right-hand pair of components shown in figure 4 illustrate the embodiment discussed above in which, in one group, a surge flow is directed upwards from below and in the adjacent and associated group, a surge flow is directed downwards from above, there being no cross-flows. Here, too, squeeze rollers, e.g., in an arrangement as shown in figure 2, can be provided although for purposes of simplification this is not illustrated herein.

The diagram shows a pressure pump 29 for delivering liquid to the surge sections 8 and a suction system or pump 30 for drawing off the liquid from the suction sections.

In addition to water, a cleaning or processing liquid can also be an acid such as sulfuric acid, or a base. During cleaning, residues can be easily flushed out of the drillings 7 that are of a small diameter, e.g., 0.1 mm.

The embodiment shown in figure 3 which incorporates the surge sections with a pre-chamber 23 and a distributor chamber 25 is the preferred embodiment of the present invention, and this can also be seen in the version shown in figure 4. The principle of the invention, discussed heretofore, can also be realized without this arrangement consisting of pre-chamber and distributor chamber, in that the processing or cleaning liquid is delivered directl~ to the surge section as shown in figure 2. This variation also applies to the embodiment shown in figure 4.

In a plant that is used for chemical processing and/or cleaning of b~ard-like objects, various kinds of combinations o~ surge sections and suction sections can be provided in the direction o~ movement 6 of the articles to be cleaned and/or processed, as is desired or in keeping with existing conditions, in particular depending on whether this involves . ,. ., - .

.
' . ' 2 ~ 8 ~

processing articles with a specific liquid (e.g. an acid, or cleaning the articles by means of water).

Claims

1. A system for processing and/or cleaning articles, in particular circuit boards incorporating drillings or drilled holes, with the aid of a liquid that is applied in a surge, wherein on one side of the article to be cleaned or processed there is a surge section and on the other side of the article there is a suction section.

2. A system as defined in claim 1, wherein the surge sections and the suction sections are opposite each other.

3. A system as claimed in claim 1, wherein a suction section is arranged so as to be offset in the direction of movement of the articles relative to the associated surge section.

4. A system as claimed in any one of claims 1 to 3, wherein the surge section or a plurality of surge sections are arranged above, and the suction section or a plurality of suction sections are arranged beneath, the path followed by the articles that are to be processed.

5. A arrangement as claimed in one of the claims 1 to 3, wherein one or a plurality of surge sections are arranged beneath, and one or a plurality of suction sections are arranged above the articles that are to be processed.

6. An arrangement as claimed in claim 1, wherein two groups, each consisting of a surge section and a suction section are arranged immediately one behind the other in the direction of movement of the articles, in the one group the surge section being arranged beneath the path followed by the articles and the suction section being arranged above the path followed by the articles and in the other group, the surge section being arranged above the path followed by the articles and the suction section being located beneath said path.

7. A system as claimed in claim 1, wherein, viewed in the direction of movement of the articles, at the entry and exit of each surge section there is an accumulator device arranged so as to lie upon the articles such that between the two accumulator means and the surge section there is an accumulated bed of liquid.

8. A system as claimed in claim 7, wherein squeeze rollers are provided as the accumulator devices.

9. A system as claimed in claim 6, wherein between groups that follow immediately one after the other and which each consist of a suction section and a surge section the partition ends at such distance from the plate-like articles that are passed through the groups, that, in addition to the surge flows that run vertically within each of these two groups, a transverse surge flow or transverse surge flows can run between the sections that are located above and/or beneath the path followed by the articles.

10. A system as claimed in claim 9, wherein the accumulator means are closely adjacent to the outer surfaces of the two groups.

11. A system as claimed in claim 1, wherein the surge section incorporates a pre-chamber with access openings or feed lines of a greater diameter; a perforated mask with drillings of smaller diameter that is adjacent thereto in the direction of flow; and a distributor chamber that is adjacent thereto in the direction of flow, said distributor chamber incorporating an outlet slot in the direction of flow of the liquid, said slot leading to a surge chamber, the series of feed lines, the pre-chamber, the drillings, the distributor chamber, the outlet slot and the surge chamber extending essentially to the whole length of the housing of the surge section.

12. A system as claimed in claim 11, wherein the drillings of smaller diameter are displaced in the direction of movement of the articles, both relative to the feed lines of greater diameter and to the outlet slot.

13. A system as claimed in any one of the claims 1 to 3, wherein, in particular in the case of shorter surge sections, the number of feed lines, as well as the size of their total cross-sectional area, is selected to be so large relative to the cross-section area of the outlet slot, that the predominant pressure drop occurs first at the outlet slot, so that in order to achieve adequate equality of the distribution of the liquid within the outlet slot on the perforated mask with the drillings, it is possible to dispense with the perforated mask with the drillings and the distributor chamber.

14. A method of processing and/or cleaning articles, in particular circuit boards that incorporate drillings, with the help of a liquid that is applied in a surge and with the use of an arrangement according to any one of the claims 1 to 3, wherein the proportion of the amount of liquid that is delivered through the particular surge section to the quantity of liquid that is drawn off through the particular suction section can be adjusted to achieve a specific effect, in particular that more liquid per unit time is drawn off in the suction section than is delivered in the surge section.