EP0059787A1 - Apparatus for the partial electroplating of electrically conductive tapes, strips or suchlike bundled parts in a continuous process - Google Patents

Abstract

A device for electroplating portions of a continuously moving, cathodically connecting workpiece as it is moved past a plurality of anodically connected spray nozzles characterized by the spray nozzles comprising precious metal and being positioned one after another in a row along the direction of movement of the workpiece with each of the nozzles having an individual stream of electrolytes emerging unimpeded therefrom. The continuously moving workpiece is positioned so that selected portions thereof are moved along the row of nozzles to be contacted by the stream of electrolyte emerging from the individual nozzles for a free and unimpeded electroplating of the portions contacted by the streams.

Description

The invention relates to a device for the partial electroplating of strips, strips or the like to be condensed parts in a continuous process, the cathodically connected strip, strip or the like being guided along an anodically connected spray nozzle.

A device of this type is known from US-PA 40 29 555. In this known device, an upright endless belt is passed through a kind of tunnel through a self-contained electroplating cell. The tape in the tunnel is covered by masks so that only the area that is to be provided with a metal layer remains free. Opposite this area, a slot-shaped nozzle connected as an anode is arranged in such a way that the electrolyte is sprayed vertically against the strip. The flowing electrolyte is collected below the slit-shaped nozzle and then reused. The length of the slot-shaped nozzle extends practically over the entire width of the electroplating cell. Due to the slot-shaped design of the nozzle, the electrolyte emerges relatively uniformly over the entire length of the nozzle. Experience has shown that in the case of electronic components combined to form individual strips, plates or the like, the beginning and end of the strips have a thicker coating, since the current densities are concentrated at the ends of the strips.

From DE-OS 20 17 527, a method and a device for applying galvanic precipitates have become known in general, the individual parts to be treated being passed under spray nozzles with the aid of a conveyor belt. It has already been proposed here that, if necessary, a plurality of spray nozzles can be attached next to one another and / or behind one another and, if appropriate, on both sides. If the metallic deposits are to be applied by the action of current, the conveyor belt is connected as the cathode, while the anodes are arranged in a container filled with electrolyte near the spray nozzles. A partial galvanization is neither provided in this known method nor possible with this known device.

From DE-OS 25 51 988 a device for the selective electrodeposition of metals has become known, in which the electrolyte liquid is applied in the form of a free jet to the fixed surface to be treated. Here, the nozzle or a part thereof is connected as an anode and the surface to be electroplated as a cathode.

In this context, it has also become known to arrange a plurality of nozzles next to one another and opposite one another. Such a nozzle arrangement is provided for the selective partial electroplating of fixed pin combs. Each pin comb is attached and contacted using a bracket. The nozzles are fastened in a preferably pivotable holder and directed against the pin E of the comb. Since the pins are fixed with respect to the nozzles, the distance between the nozzles must be equal to the distance between the pins on the comb. Since in practice it cannot be avoided that from the Electrolyte jets emerging from the nozzles are unequal to one another, inevitably there are deposits of different thicknesses. Furthermore, since the nozzles are also opposite one another in the case of opposing nozzle arrangements, a mutual hindrance of the opposing nozzles cannot be avoided.

Finally, a device for plating the connection pins of a printed circuit board has become known from US Pat. No. 4,186,062, the printed circuit boards being gripped by toothed belts arranged on both sides and being passed through an electrolyte cell. The timing belts cover the areas of the circuit board that are not to be galvanized tightly. The electroplating is carried out by supplying the electrolyte to the plate via holes directed upwards and arranged in a row. With the help of a curved foil, the electrolyte flow is deflected in a certain direction so that a kind of Venturi effect is created on the circuit board.

The invention has for its object to provide a device of the type described in such a way that not only tapes, but also strips, combs, plates or the like can be partially galvanized. It is ensured that not only a uniform layer thickness with little layer thickness scattering occurs , but also any desired layer thickness distribution can be achieved.

This object is achieved with a device of the type described at the outset according to the invention in that the cathodically connected band or the like is attached to a A plurality of anodically connected spray nozzles made of noble metal is guided along, which, viewed in the direction of movement of the strip or the like, are arranged one behind the other and directed towards the strip or the like in such a way that the electrolyte jet emerging from each individual spray nozzle is free and unimpeded onto the area to be galvanized on the Band or the like.

The continuous movement of the belt or the like along the nozzles produces a layer thickness which is always constant because the belt passes through each individual nozzle. The thickness of the layer depends, among other things, on the speed at which the strip passes the individual nozzles. Thus, it cannot happen that when galvanizing strips, combs, plates or the like. These have a thicker coating at the beginning and end than the middle part, since the current density along the nozzle arrangement remains practically constant, since each individual nozzle with the cathodic switched band or the like practically forms its own galvanic cell. The distance between the individual spray nozzles can be selected so that the cells practically do not influence one another.

The diameter of the nozzles and the distance of the nozzles from the belt or the like are preferably such that a current density distribution corresponding to the desired layer thickness distribution is produced between the belt or strip and nozzles. In this way, any layer thickness distribution can be achieved, so that, for example, in knife strips, the areas can be provided with a thicker coating that are subject to greater wear than other areas. This can save a lot of precious metal on precious metal contacts, as experience has shown.

According to a further feature, the distance of the spray nozzles from one another is not the same or not equal to a multiple of the division of the parts combined in the band. In this respect, the device according to the invention differs significantly from the device according to DE-OS 25 51 988, in which the distance between the nozzles must be equal to the distance of the pins on the comb, since otherwise an uneven layer thickness distribution results. Because the distance between the spray nozzles from one another is not the same as the division of the parts combined in the belt or the like, the total dynamic pressure across all the nozzles is approximately the same, so that the strength of the individual spray jets is not subject to any fluctuations. This is particularly important when the nozzles are arranged close to the area to be galvanized on the belt. By bringing the nozzle ends as close as possible to the areas to be galvanized, considerably higher current densities between the nozzles and the strip are achieved, which results in higher deposition rates. This can either keep the overall length of the nozzle arrangement shorter or increase the belt speed.

Another possibility of a targeted layer thickness distribution results from the fact that the individual spray nozzles have a smaller diameter than the width of the areas to be galvanized on the strip and that the individual spray nozzles are not only arranged one behind the other in the direction of movement, but also perpendicularly to one another such that the in the order of the first spray nozzle the one (upper) and the last spray nozzle the other (lower) range limit. In practice, this can be achieved in a simple manner by preferably grouping them together seized nozzles, which are used in a common container to form a spray cell, offset by tilting the container parallel to the belt. By appropriately tilting the spray cell, a more or less wide area on the strip can be partially galvanized. In accordance with this inclination, the belt speed must then be set accordingly in order to achieve a certain layer thickness.

It has proven to be expedient if the individual nozzles are positioned at an angle to the strip in such a way that the sprayed electrolyte flows out in a preferred direction. As a result, the exit velocity of the electrolyte from the nozzles can be increased. The more this angle deviates from the perpendicular to the band, the better the flow distribution, so that at least partially sharply delimited areas of the coating result.

If both sides of the strip are to be partially galvanized, spray nozzles are arranged on both sides of the strip in a manner known per se which, according to the invention, are at a distance from one another so that the nozzles do not interfere with one another.

If the electrolyte is sprayed at a very high speed, it is inevitable that electrolyte is also sprayed onto areas which are not to be galvanized and which may then have to be cleaned again later. In this case it is advantageous that at least these areas of the band are covered by at least one mask in a manner known per se. It is useful if the mask is part of the leadership of the Band forms. If, for example, connector strips, connector pins or the like are to be partially galvanized with the aid of masks, it is advantageous that the masks move with the tape or the strips in a speed-compatible manner at least over the length of the spray cell.

As has already been explained above, it is advantageous that the spray nozzles arranged on at least one side of the belt are used to form a spray cell in a common container which is designed and held under pressure such that each of the electrolyte jets emerging from the individual spray nozzles has approximately the same strength. A particularly simple construction of a spray cell results according to the invention in that it consists of one noble metal tube, e.g. Platinum, existing spray nozzles in a tubular container made of corrosion-resistant material, e.g. Titanium are used, which is preferably closed on one side and has a connecting piece for electrolyte liquid on the other side. So that approximately the same electrolyte pressure arises at all spray nozzles, it is advantageous that a preferably concentrically arranged distributor pipe is arranged in the interior of the tubular container, via which the electrolyte is supplied and in which holes are provided in a corresponding distribution on the side facing away from the spray nozzles are.

Such a container can be easily adjusted with respect to the belt or the like so that the distance of the spray nozzles from the belt and the direction of the spray nozzles to the belt can be changed. The spray direction can be changed in a simple manner in that the container is designed to be pivotable about its longitudinal axis.

The invention is explained in more detail with the aid of the drawing, in which several exemplary embodiments are shown in part purely schematically.

• Figur 1 eine-perspektivische Ansicht einer Vorrichtung mit einer Sprühzelle zum partiellen Galvanisieren von zu leitenden Bändern oder Streifen zusammengefaßten elektrischen Bauteilen, wobei mit strichpunktierten Linien angedeutet ist, wie die zu beschichtenden Bänder oder Streifen kontaktiert und bewegt werden,
• Figur 2 einen teilweise vergrößert dargestellten Teil des zu beschichtenden Bandes,
• Figur 3 eine Vorrichtung mit zwei Sprühzellen, die zu beiden Seiten des Bandes angeordnet sind,
• Figur 4 eine Seitenansicht der Vorrichtung gemäß Fig. 3 im Schnitt in verkleinerter Darstellung,
• Figur 5 in vergrößerter Darstellung einen Teil eines beschichteten Stiftes eines Bandes und
• Figur 6 eine bevorzugte Ausführung einer Sprühzelle im - Schnitt.

Show it:

• FIG. 1 shows a perspective view of a device with a spray cell for the partial electroplating of electrical components combined into strips or strips to be conducted, dash-dotted lines indicating how the strips or strips to be coated are contacted and moved,
• FIG. 2 shows a part of the strip to be coated, shown in a partially enlarged form,
• 3 shows a device with two spray cells which are arranged on both sides of the belt,
• FIG. 4 shows a side view of the device according to FIG. 3 in section in a reduced representation,
• Figure 5 shows an enlarged view of part of a coated pin of a tape and
• 6 shows a preferred embodiment of a spray cell in section.

As FIG. 1 shows, the parts 1 to be coated are combined to form a conductive tape 2. After the coating and other treatment, the parts 1 are separated in a manner known per se. The tape 2 is usually 'wound on a roll and is drawn off by an unwinding device not shown in the drawing and runs into the electroplating system. It travels through a number of pretreatment stations in a manner known per se and then finally runs into the actual electroplating cell 4, the principle of which is shown in FIG. Volume 2 is here in The direction of the arrow 3 is drawn into the electroplating cell 4. Immediately in front of the actual spray cell, a pair of contact rollers 5 are provided for contacting the belt 2, which also serve as a guide. Due to a slight inclination of these contact rollers 5 to the direction of travel, the tape is pressed slightly against a stop. This gives an exact position of the belt to the spray cell. Immediately after the ^p rühzelle S is also provided by contact rollers 6, a pair, which also serve for contacting and guiding the strip. The band 2 then continues through the plant and is at the end again with the help of a winding device. Roll wound up.

The band 2 is guided along a row of nozzles 7, which are inserted in a tubular container 8 designed as a spray cell. As indicated by an arrow 9, electrolyte is pumped into the tubular container 8, which then exits through the nozzles 7. The nozzles 7 are directed against the area B to be coated, the diameter d of the nozzles 7 and the distance a from the strip 2 being matched to one another in such a way that the current density distribution corresponds approximately to the desired layer thickness distribution (FIG. 2).

Figure 2 shows. on an enlarged scale, the arrangement of the nozzles 7 with respect to the area B to be galvanized of the parts 1 on the strip 2. In FIG. This is expedient if, as shown in FIG. 2, the area B of the part 1 to be coated is curved. If this is not the case, it may be expedient that the angle α between the nozzle axis 10 and the belt plane is made less than 90 °. This adjustment of the angle can be made in a simple manner so that the tubular container 8 is rotated about its longitudinal axis 11 accordingly. The nozzles 7 used in the tubular container 8 are preferably arranged at the same distance D from one another, but the distance D is not equal to a multiple of the distance t of the components combined in the band 2.

As is indicated in FIG. 1, the area of the strip 2 that is not to be galvanized can be covered. can be made, for example, by corresponding masks 12 and ₁₃ , which are pressed elastically against the band 2. However, if the band consists of individual parts, for example contact pins, which are more or less free, there is a risk that these parts 1 will be bent and damaged. In this case, it is expedient if the masks 12 and 13 move according to FIG. 1 with the belt in a speed-compatible manner. This can be achieved in a simple manner if circumferential belts are used as masks 12 and 13, as are also used, for example, in a device described in DE-OS 29 28 904. As a result, there is also the possibility of partially galvanizing parts combined into strips, such as pin combs or the like, and also circuit boards.

FIGS. 3 and 4 show an exemplary embodiment with two spray cells, contact pins 14 being combined into a band to be galvanized at the lower free end, from both sides. In this case, on both sides of the belt 2 tubular containers 8 and 8 'with spray nozzles 7 and 7' are provided, which are directed against the area to be plated on the contact pins 14. The arrangement and configuration of the nozzles 7 and 7 'essentially corresponds to the configuration according to FIG. 1, but in this case they are opposite one another the nozzles 7 and 7 'offset from one another to a gap, so that the electrolyte jets emerging from the individual nozzles 7 and 7' do not influence one another. The two tubular containers 8 and 8 'are arranged within an electrolyte trough 15, as shown in FIG. 4.

If, for example, the lower end of a contact pin ₁ 4 is to be galvanized in such a way that the distribution of the layer 26 shown in FIG. 5 is produced, such a uniform layer thickness distribution can only be achieved if the diameter d of the individual nozzles 7 is significantly smaller than that galvanizing area B of the connector pin 14 and when the nozzles 7A to 7N are also offset transversely to the direction of movement of the strip, in total by an amount c. This can be achieved in a simple manner in the spray cells according to FIGS. 1 and 3 in that the container or containers 8 are inclined parallel to the belt by the amount c, so that, for example, the first spray nozzle 7A in the order the upper and the last spray nozzle 7N detected the lower range limit. For the sake of clarity, the amount c is chosen exaggerated. As already mentioned at the beginning, any desired layer thickness distribution can be achieved in this way.

Figure 6 shows an advantageous embodiment of a spray cell, in particular for partial gold plating. The cell consists of a tube 16 made of corrosion-resistant material, for example titanium, in which tubes 17 made of precious metal, for example platinum, are used as nozzles 7. For this purpose, the tube 16 is provided with corresponding bores into which the tubes 17 are inserted, for example by pressing. At one end of the tube 16, a plug 18 made of corrosion-resistant material, for example plastic, is inserted, which Pipe 16 closes tightly. The other end of the tube ₁ 6 has a connecting piece 19 for connection to an electrolyte supply, as indicated by an arrow 20. So that the electrolyte jet emerges uniformly from all the tubes 17, a distributor tube 2 _{1 is} arranged inside the tube 16, preferably concentrically thereto, one end of which is pushed over a molded part 22 of the stopper and the other end of which in a corresponding bore 23 of the connecting piece ₁₉ is centered. The distributor tube 21 is provided on the side facing away from the tube ₁₇ with openings in the form of bores 24, through which the electrolyte exits and pours around the distributor tube 21 on both sides before it reaches the tube 17 and exits there.

The spray cells shown in FIGS. 1, 3 and 4 are preferably also designed in the same way as the spray cell according to FIG. 6. Such a cell can be inserted into a simple holder which allows both rotation about its longitudinal axis 25 and adjustment of a certain one Inclined position C parallel to the strip for setting a defined coating width B and also setting an optimum distance for the galvanization of the nozzle ends from the areas to be galvanized is permitted.

Reference symbol list

• 1 parts
• 2 volume
• 3 arrow direction
• 4 electroplating cell
• 5 contact rollers
• 6 _n
• 7 nozzles
• 8 spray cell containers
• 9 arrow
• 10 nozzle axis
• 11 longitudinal axis
• 12 mask
• 13 "
• 14 contact pin
• 15 electrolyte trough
• 16 pipe
• 17 tubes
• 18 plugs
• 19 connecting piece
• 20 arrow
• 21 manifold
• 22 molding
• 23 hole
• 24 "
• 25 longitudinal axis
• 26 layer

Claims (17)

_1st Device for the partial electroplating of parts combined into electrically conductive strips, strips or the like in a continuous process, the cathodically connected strip or the like being guided along at least one anodically connected spray nozzle, characterized in that the cathodically connected strip (2) or the like. is guided along a plurality of anodically connected spray nozzles (7) made of precious metal, which are arranged one behind the other in the direction of movement of the belt (2) or the like and directed towards the belt (2) or the like. are that the electrolyte jet emerging from each individual spray nozzle (7) hits the area (b) to be galvanized on the belt (2) or the like freely and unhindered. 2. Device according to claim 1, characterized in that the diameter (d) of the nozzles (7) and the distance (D) of the nozzles (7) from the belt (2) or the like. Is dimensioned such that between the belt (2) and Nozzles (7) a current density distribution corresponding to the desired layer thickness distribution arises. 3. Apparatus according to claim 1 or 2, characterized in that the distance (D) of the spray nozzles (7) from one another is not the same or not equal to a multiple of the division (t) of the parts (1) combined in the band or the like. 4. Device according to one of claims 1 to 3, characterized in that the diameter (d) and the distance (D) of the individual spray nozzles (7) from one another is chosen so that no mutual influence of the electrolyte jets emerging from the spray nozzles (7). 5. Device according to one of claims 1 to 4, characterized in that the individual spray nozzles (7) have a smaller diameter (d) than the width of the areas to be galvanized (B) on the belt (2) or the like. And that the individual spray nozzles (7) not only one behind the other in the direction of movement, but also vertically offset so that the first spray nozzle (7A) in the order detects one (upper) and the last spray nozzle (7N) the other (lower) range limit. 6. Device according to one of claims 1 to 5, characterized in that the individual spray nozzles (7) in such an angle α against the band (2) or the like. That the sprayed electrolyte flows out in a preferred direction. 7. Device according to one of claims 1 to 6, characterized in that on both sides of the belt (2) or the like. Spray nozzles (7a, 7b) are arranged which are mutually spaced. 8. Device according to one of claims 1 to 7, characterized in that at least a region of the band (2) or the like. Covered by at least one mask (12 or 13). 9. The device according to claim 8, characterized in that the mask forms part of the guide of the band (2) or the like. 10. The device according to claim 8 or 9, characterized in that the mask (12, 13) itself at least along the length of the nozzle arrangement with the belt (2) or the like. 11. The device according to claim 10, characterized in that endless belts are used as a mask (12, 13), between which part of the belt (2) or the like is clamped. 12. Device according to one of claims 1 to 11, characterized in that the at least on one side of the belt (2) or the like. Spray nozzles (7) arranged in a common container (8) are used, which are designed and held under pressure is that each of the electrolyte jets emerging from the individual spray nozzles (7) has approximately the same strength. 13. The apparatus according to claim 12, characterized in that each of a noble metal tube (17), e.g. Platinum, existing spray nozzles in a tubular container made of corrosion-resistant material, e.g. Titanium are used, which is preferably closed on one side and has a connecting piece (19) for electrolyte liquid on the other side. 14. The device according to claim 13, characterized in that in the interior of the tubular container (16) a preferably concentrically arranged distributor pipe (21) is arranged, via which the electrolyte is supplied and in the holes on the side facing away from the spray nozzles (17) (24) are provided, which are arranged in such a way that approximately the same electrolyte pressure arises at all spray nozzles (17). 15. The device according to one of claims 12 to 14, characterized in that the container or containers (8) are adjustable with respect to the belt (2) or the like so that the distance of the spray nozzles (7) from the belt (2) or the like and the direction of the spray nozzles (7) to tape (2) are changeable. 16. The apparatus according to claim 15, characterized in that the tubular container (8) about its longitudinal axis (11) is pivotable. 17. Device according to one of claims 12 to 16, characterized in that in the case of long containers (8) the electrolyte is fed in at several points, in particular at the two ends.

Images