WO1991007527A1

WO1991007527A1 - Device for reducing the concentration of field lines in an electroplating plant

Info

Publication number: WO1991007527A1
Application number: PCT/DE1990/000884
Authority: WO
Inventors: Manfred Kallweit; Walter Meyer; Rolf Schröder
Original assignee: Schering Aktiengesellschaft
Priority date: 1989-11-15
Filing date: 1990-11-14
Publication date: 1991-05-30
Also published as: DE3937926A1; DE3937926C2

Abstract

In known devices for reducing the concentration of field lines in an electroplating plant for treating disk-shaped workpieces, a diaphragm is associated with a lower end region of a workpiece. Such a diaphragm, which is moved together with the workpiece in an electrolytic bath, can be used only in vertical electroplating plants and its shape or size cannot be adapted to the shape and size of a workpiece to be treated. The invention relates to a diaphragm device (6) with one or more diaphragms (7) which are associated with one of the faces of the anode (1) facing the workpiece (2) such that the concentration of field lines (4) between the anode (1) and the workpiece (2) can be reduced, completely or partly, in a predetermined manner.

Description

"Device for stopping field lines in a galvanic plant"

The invention relates to a device for stopping field lines in a galvanic system for treating essentially plate-shaped workpieces, which is provided with a diaphragm.

In a generic device (DE-PS 37 26 571), a circuit board as a workpiece to be treated in a diving galvam system is assigned a shielding and positioning frame, with a roof-shaped base that is guided so as to be displaceable in a vertical direction. The screen is in a basic position on the bath surface and is carried along by it when the workpiece is immersed.

The known diaphragm, which is assigned to a workpiece, can only be used in vertical galvanizing systems. Their effectiveness is further limited by the fact that a workpiece is to be electroplated, regardless of its size and / or shape, a single aperture of unchangeable size and shape. To achieve a uniform layer thickness distribution in the

To achieve electroplating system to be applied to the workpiece electroplating, it is also known to attach panels or rails below a lower edge of a workpiece to be treated, through which field lines appearing in this area are partially attracted.

The invention has for its object to develop a generic device so that a substantially uniform field line density between an anode and the workpiece is achieved in a simple manner and adapted to the respective size and shape of a workpiece, while avoiding places high Feldliπien Concentration, is achieved.

This object is achieved according to the invention in a device of the aforementioned type by the characterizing features of claim 1.

According to the invention, one or more electrically non-conductive screen devices with a shape and size that is independent of the respective workpiece size and workpiece shape are assigned to a side of the anode facing the workpiece. The assignment takes place depending on the respective workpiece size and the respective workpiece shape in such a way that field lines between the anode and the workpiece are completely or partially dimmed.

It is thus achieved in a simple manner both for vertical and for horizontal electroplating systems that points of high field line concentration are avoided, adapted to the size and shape of a workpiece to be treated in each case, and that over the area of the workpiece to be coated with an electroplating layer an essentially homogeneous field line density is achieved. When treating successive workpieces which differ in terms of their size and shape, it is therefore only necessary to achieve an essentially homogeneous field line density that after the treatment of a workpiece and before the treatment of a subsequent workpiece, the anode is adapted to the size and shape of this workpiece one or more Blendeπvorrichtungen be assigned.

The device according to the invention can thus be used very flexibly and can also be retrofitted in a simple manner even in the case of existing galvanic systems.

In a preferred embodiment, one or more of the plate devices are arranged movably and can be locked in at least one dimming and at least one open position. Depending on the shape and size of a workpiece, for example, a single diaphragm device can thus be moved into a dimming position determined by the workpiece size and workpiece shape and can be fixed there. If several anode devices are assigned to the anode, then for an essentially homogeneous field line distribution with respect to a surface of a workpiece to be electroplated, and in order to avoid the occurrence of a high field line density at least in one edge area of the workpiece, individual of the plate devices in the passage position and others can be used diaphragm devices adjoining an edge region of the workpiece are moved into a dimming position and are fixed there for the duration of the treatment of the workpiece.

With regard to a movement of one or more diaphragms, it has proven to be advantageous that they are connected to a pivotably mounted axis. Baffles of this type can be inserted into a cover in a particularly simple manner. dazzle position, in which they are arranged substantially parallel to the anode and in a passage position, in which they are arranged essentially at a right angle to the anode.

It has proven advantageous that the axis is arranged essentially in a central region of the or each diaphragm.

It is also particularly advantageous that a plurality of adjacent screens are designed and arranged in such a way that adjacent areas of adjacent screens overlap in a low position. This prevents in a simple and reliable manner that in areas of diaphragms arranged in a dimming position, field lines can run from the anode towards the workpiece.

In a further preferred embodiment there is a band-like diaphragm device which can be moved via at least one transport roller. Such a screen can be easily wound onto or from the transport roller in accordance with the size and shape of a workpiece to be treated. By winding or unwinding the band-like diaphragm device, the latter can be brought substantially continuously into a respectively dimmable or pass-through position in which it can then be fixed.

The band-like diaphragm device can be formed from a flexible film and / or interconnected thin plate segments.

In a further preferred embodiment, one or more aperture devices can be moved via a controllable drive. The controllable drive can be used with one axis connected diaphragms for pivoting the axis cooperate with this. In the case of belt-like diaphragms which can be moved via at least one transport roller, the controllable drive can interact with the transport roller. In this case, however, the drive can also act on one end of the band-like diaphragm, for example via a rope as a tension element; in this case, the sports roll can be set in rotation over the wound-up part of the band-like screen.

In all cases, instead of the controllable drive or as an alternative to this, the possibility can also be created for manual movement of the lead devices.

For use, in particular, in flexibly usable and essentially automatically operated electroplating systems, it has proven to be advantageous that a control circuit with a device for detecting the workpiece size or shape and an actuating device for a movement dependent on the detected workpiece size or shape one or more diaphragm devices are arranged in a Abbleπd- or passage position. This means that, regardless of the shape and size of the workpieces to be treated in each case, automatic operation of automatic electroplating systems is made possible, in each case during the treatment of a workpiece ensuring that no locally high field line concentrations can occur and the field line density is related to that area of the workpiece to be coated is essentially homogeneous.

According to the invention, for example, in an electroplating system, screens connected to an axis and movable via them can be assigned to an anode in both a vertical and a horizontal arrangement. For systems with a wide range of variations in the shape and size of workpieces to be treated, it can be feasible that at least in some areas screens are arranged both in the vertical and in the horizontal direction. Furthermore, it is possible to use diaphragms which are connected to an axis and can be moved via these, together with a band-like diaphragm which can be moved via a transport roller.

The invention is explained in more detail below with reference to the drawing. They each show a simplified schematic representation

1: a plan view of an anode and a workpiece with a field line distribution corresponding to a conventional electroplating system,

2: a plan view of an anode and a workpiece corresponding to FIG. 1 with a first exemplary embodiment of a device according to the invention for stopping field lines,

3: a side view relating to the in

2 shown first embodiment,

4: a plan view of an anode and a workpiece with a device for stopping field lines according to a second exemplary embodiment and

5: a side view relating to the in

Fig. 4 shown second exemplary embodiment.

In the figures, no details of a galvanic would only be shown and described in each case only the area required for the explanation of a device for stopping off field lines or a field line distribution. The device according to the invention for stopping field lines can be used, for example, in vertical or horizontal electroplating systems and in automatically operating electroplating systems, regardless of the particular type. The device according to the invention can, for example, also be installed in a simple manner in already existing electroplating systems and can be used advantageously in these.

1, which does not have a device according to the invention for shielding field lines, an anode 1 is at a distance from an essentially plate-shaped workpiece to be provided with a metallic coating

2 opposite. Via a circuit shown schematically

3 with connections both on the anode 1 and on the workpiece 2 there is a direct voltage between them, on which field lines 4 form between the anode 1 and the workpiece 2. The distribution of the field lines 4 is only homogeneous in a central region of the workpiece 2 with field lines running essentially parallel to one another, while in the upper and lower edge regions of the anode 1 there are regions 5 of the workpiece 2 for which results in a high field line concentration. The high exposure of the areas 5 to the field lines 4 results from the fact that the workpiece 2 is smaller than the anode 1, so that an upper and lower edge area 2 'or 2 "of the workpiece 2 has a larger anode area which is essentially extending from the upper and lower end regions 2 ', 2 "to the upper and lower ends of the anode 1, respectively. In contrast, a correspondingly large area of the anode 1 lies opposite a central area of the workpiece 2, so that there sets up an essentially homogeneous field line distribution.

In the areas 5 of the workpiece 2 with an exposure 5 to field lines of high concentration, more metal ions are deposited within a galvanic bath, not shown, within which the anode 1 and workpiece 2 are arranged. In the areas 5 there is thus a higher layer, thickness of the electroplated coating than the other areas of the workpiece 2, by means of which the quality of the coating and thus of the treated workpiece 2 is reduced. In particularly unfavorably positioned cases, there may also be cracks within the areas 5 with a correspondingly high current density, i.e. 15 bud-shaped or columnar deposits of the metal, which also reduce the quality of the treated workpieces 2.

In order to achieve the mentioned disadvantages with regard to the workpiece 2 to be treated, high field line concentrations

To avoid within the areas 5, it is known, for example, that the geometry of the anode 1 is designed to be essentially identical to that of the workpiece 2. However, this leads to a considerable outlay in relation to the galvanic treatment of workpieces 2.

25 different sizes; this procedure is therefore in particular not suitable for use in automatically operating galvanic systems.

With a further known diaphragm (DE-PS 37 26 571), each assigned to a workpiece 2, a high field line concentration can be achieved in the area of one of the ends 2 ', 2 "in vertical electroplating systems In vertical electroplating systems, a reduction in quality as a result of high field line concentrations occurring can be avoided if an end of the workpiece 2 opposite the screen is arranged congruently with one end of the anode 1. In the first exemplary embodiment shown in FIG. 2 regarding a device according to the invention for stopping field lines, the formation of essentially homogeneously distributed field lines is without restriction with regard to use in vertical or horizontal galvanizing systems and without the need for a special arrangement of the workpiece 2 enables. The arrangement of the anode 1, the workpiece 2 and a circuit 3 corresponds to that of FIG. 1, so that corresponding reference numerals are used. Associated with the anode 1, between it and the workpiece 2 there is a diaphragm device, generally designated 6, for stopping field lines, which consists of a plurality of diaphragms 7 spaced apart and adjacent to one another. The arrangement of the screens 7 is independent of the shape or size of the workpiece 2 such that screens 7 are arranged essentially over the entire length of the anode 1. The Bler.Jen 7, which are of essentially the same design and are electrically non-conductive, each have an axis 8, which is pivotably mounted in a manner not shown, in a central region. Each of the diaphragms 7 can be made electrically non-conductive, for example from an insulating material, or can be provided with an insulating coating and has an essentially rectangular shape with a longitudinal direction running in the direction of the axis 8. Each of the diaphragms 7 can be moved about the associated axis 8, which in the present case is arranged vertically, into a dimming position in which, as can be seen from FIG. 2, adjacent regions of mutually adjacent diaphragms 7 overlap. It is thus prevented in a safe and simple manner that, starting from the areas of the anode 1 which lie opposite the screens 7 in the dimming position, field lines run in the direction of the workpiece 2. In the dimmer position, in which the diaphragms 7 can be ascertained by means of locking devices (not shown, for example acting on the axes 8, manually or automatically operated) Apertures 7 are arranged essentially so that they lie in a plane running parallel to the array 1. For a homogeneous loading of the workpiece 2 with field lines, the diaphragms 7 opposite the workpiece 2 have been moved into a passage position which is essentially transverse to the dimming position and are fixed there in a manner not shown. The screens 7 are arranged in this area, essentially parallel to one another, essentially at right angles to the anode 1 and the workpiece 2. In the area of the diaphragms 7 in the open position, there is an essentially homogeneous distribution of the field lines 4 for a substantially uniform metallic coating of the workpiece 2 to be treated.

The arrangement according to the invention of diaphragms 7 which can be moved from a dimming position into a passage position and which can be locked there can thus easily avoid the occurrence of locally high field line concentrations. Depending on the size, shape and arrangement of the workpiece 2 relative to the anode 1, it is only necessary, as can be seen in FIG. 2, that those screens 7 that are not between the workpiece 2 and the anode 1 are in their dipped position are moved and fixed there, while the screens 7 located between the respective workpiece 2 and the anode 1 are moved into their open position and are fixed there. With the device 6 according to the invention for stopping field lines 4, field lines 4 can thus be covered in a simple, quick and safe manner in such a way that a workpiece 2 to be treated, regardless of its size or shape, essentially with field lines of a homogeneous one Distribution is applied. For the treatment of successive workpieces 2 of different sizes and / or shapes, it is only necessary that after the completion of the treatment of a workpiece and before the start of the treatment for the subsequent workpiece, diaphragms 7 are determined according to the size, shape and arrangement of this workpiece with respect to the anode 1 in its shielding or open position. As can be seen from FIG. 3, diaphragms 7 are arranged with their axes 8 in the horizontal direction according to the first exemplary embodiment, the workpiece 2 likewise being immersed in an electroplating bath (not shown) opposite the anode 1 in the horizontal direction indicated by the arrow 9 is moved. In the case of a vertical electroplating system, comparable screens 7 can be arranged in the vertical direction, and it is also possible, if appropriate, for screens 7 to be arranged at least in regions both in the horizontal and in the vertical direction.

In the second exemplary embodiment shown in FIGS. 4 and 5 relating to a plate device 10 according to the invention for stopping field lines, the diaphragm is formed in a band-like manner from a flexible film 15 and / or thin plate segments which are connected to one another and which are partially supported on a transport roller 11. and can be developed or moved in the directions indicated by the double arrow 12. The band-like screen 15 can be moved essentially parallel to the anode 1 along the workpiece 2 such that its front end 15 'is arranged substantially congruently with the upper end 2' of the workpiece 2. The band-like diaphragm 15 is connected at its end 15 'to a tension element 13, for example in the form of a rope, which can be moved in the directions of the double arrow 12 via a roller 14. In this way, the upper end 15 'can be easily fixed to the size of the workpiece 2, in accordance with the upper end 2' of the workpiece 2 in a shielding or open position. For this purpose, for example, the tension element 13 and the panel 15 can be kept under tension by fixing the transport roller 11 or the roller 14 or both. Since the band like screen 15 is capable of dimming the anode 1 from the workpiece 2 only from one side, it is expedient that, as shown in FIG. 4, the lower end 2 "of the workpiece 2 is arranged in correspondence with the lower end of the anode 1 becomes.

Corresponding to the use of the diaphragm device 10, a homogeneous field line distribution, not shown, results for the workpiece 2, which corresponds to that according to FIG. 2.

When using a device for blocking field lines in a galvanic system with an arrangement of diaphragms 7 according to the first exemplary embodiment or with an arrangement of a diaphragm 15 according to the second exemplary embodiment or with a combined arrangement of diaphragms 7, 15 according to the first and second exemplary embodiments It is particularly advantageous when the electroplating system is to be operated automatically that, in a manner not shown, optionally in addition to a corresponding manual device, a controllable drive for driving each of the screens 7 or a single drive for driving the band-like screen 15 the transport roller 11 or the roller 14 is present. For automation, a device (not shown) for detecting the workpiece size or shape and, if appropriate, the workpiece arrangement relative to the anode 1 may also be present. This then interacts via a control loop with an actuating device containing the controllable drive, in order to move one or more diaphragms 7, 15 into a shielding or passing position depending on the workpiece size or workpiece shape detected.

Claims

Claims:

1. Device for stopping field lines in a Galvaπik- aπlage for treating substantially plate-shaped workpieces, with an aperture, characterized in that one or more of the workpiece (2) facing side of an anode (1) adapted to the respective workpiece size and shape electrically non-conductive diaphragm devices (6, 10) are assigned in such a way that field lines (4) between the anode (1) and the workpiece (2) are completely or partially dimmed.

2. Device according to claim 1, characterized in that one or more of the diaphragm devices (6, 10) are arranged movably and can be determined in at least one dimming and at least one passage position.

3. Apparatus according to claim 2 or 3, characterized in that one or more diaphragms (7) of a Blendeπvorrichtung (6) each with eiπejr pivotally mounted axis (8) are connected.

4. The device according to claim 4, characterized in that - The axis (8) is arranged substantially in a central area of the or each panel (7).

5. Device according to one of claims 1 to 4, characterized 5 in that a plurality of adjacent diaphragms (7) are designed and arranged such that - in a dimming position, adjacent areas of adjacent diaphragms (7) overlap.

6. Device according to one of claims 1 to 2, characterized by a belt-like diaphragm device (10) which can be moved via at least one transport roller (11).

7. The device according to claim 6, characterized in that 5 the diaphragm device (10) is formed from a flexible film (15).

8. Apparatus according to claim 6 jder 7, characterized in that the aperture device has thin plate segments with each other.

9. Device according to one of claims 1 to 8, characterized in that one or more aperture devices (6, 10) are each movable 5 via a controllable drive.

10. Device according to one of claims 1 to 9, gekennzeich¬ net by a control circuit with a device for detecting the size or shape of a workpiece (2) and a 0 adjusting device for one of the detected size or shape of the workpiece (2) dependent movement of one or more plate devices (6, 10) into a dimming or passage position.

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