WO1999010563A2

WO1999010563A2 - Method and device for energy saving simultaneous electrolytic treatment of several workpieces

Info

Publication number: WO1999010563A2
Application number: PCT/DE1998/002501
Authority: WO
Inventors: Helmut Stiegler; Jens Maschmeyer
Original assignee: Atotech Deutschland Gmbh
Priority date: 1997-08-21
Filing date: 1998-08-19
Publication date: 1999-03-04
Also published as: WO1999010563A3; DE19736351C1; EP1015671A2; JP2001514329A

Abstract

The energy relates to a device and a method for energy saving simultaneous electrolytic treatment of several workpieces connected in the form of electrodes, each having the same electrolysis current. The inventive device comprises at least two electrolytic partial cells in a tank and at least one power source supplying the partial cells with an electrolysis current. The partial cells also have support fixtures that are used for electrical contacting with workpieces attached thereto, in addition to at least one respective counter electrode. The workpieces are connected as cathodes and the counter electrodes are connected as anodes during electroplating of said workpieces. During etching and deplating, said workpieces are connected as anodes and the counter electrodes are connected as cathodes.

Description

Method and device for the energy-saving simultaneous electrolytic treatment of several workpieces

Description:

The invention relates to a method and a device for the energy-saving simultaneous electrolytic treatment, in particular electroplating, of several workpieces connected as electrodes, each with the same electrolysis current (electroplating current) in immersion bath electrolysis systems.

In known plating bath electroplating systems, goods carriers are transported from one or more transport devices from treatment station to treatment station, also called bath for short. The workpieces to be electroplated are attached to the product carriers in the loading station. As a rule, there are many workpieces that a product carrier holds. All workpieces are electrically connected to the goods carrier and connected in parallel. After treatment and drying, the workpieces are removed from the goods carrier in an emptying station. For technical and / or economic reasons, it is necessary to adhere to a predetermined layer thickness tolerance of the metal to be electrolytically deposited on the workpiece. Precise, even deposition of metal enables post-treatments such as Grinding is not necessary to achieve an exact dimension.

The amount of metal deposited is almost proportional to the electroplating current in the electroplating cells commonly used and the current densities used therein. For the precise electroplating of workpieces, it is therefore necessary for each workpiece to be supplied with a very specific electroplating current. For the same workpieces on a product carrier therefore each workpiece can be supplied with the same current. Even with different workpieces, there may be a demand for the same electroplating current for each workpiece. These are workpieces that have the same surface, but a different shape. Examples of this are bars that differ in the right and left-hand threads at the end, or right and left parts that are otherwise the same. The entire current flowing on the goods carrier in an electrolytic cell is distributed among the workpieces attached to it. Only when all resistances of the partial circuits formed by the workpieces are of the same size can the partial currents, ie the currents flowing through the workpieces, be of the same size. In the case of product carriers used in production plants and the brackets attached to them, the partial resistances are always different. The reasons for this are different sized cross sections and lengths of the electrical conductors on the goods carrier, which are effective for each partial circuit, as well as contact resistance at the goods carrier clamping points and at the workpiece clamping points, which are not constant in the long run. Likewise, the electrical conditions of the anodes arranged opposite the individual workpieces are not constant. In practice, this can lead to the fact that even one or more workpieces of a product carrier do not carry any electricity at all. The remaining current-carrying workpieces of the goods carrier take over the current of the failed workpieces. Different layer thicknesses are inevitable. The currents on the individual workpieces cannot be measured with reasonable technical effort, and therefore cannot be monitored. Instead of individual workpieces on a product carrier, electroplating frames can also be processed with material to be treated. In this case, the electroplating frame corresponds to a workpiece, which in turn is attached to a goods carrier.

DE-OS 1 800 954 describes a copper bath tub for simultaneous galvanic deposition of copper coatings on a large number of workpieces of different and / or irregular shapes. In order to achieve copper layer thicknesses that are as uniform as possible, stationary series resistors are used to match the galvanizing currents of individual workpieces. beat. The partial flows are fed by a bath current source with a correspondingly large total current. The series resistors are individually adjustable. With the necessary effort, the electroplating currents of the workpieces can be set to the same size. In addition to the great technical outlay, the disadvantageous disadvantage is the disadvantageous efficiency, in particular when the sum of the partial flows takes on a very high value, since in this case a large amount of electrical energy is converted into useless thermal energy.

EP 0 308 636 B1 describes a method for equalizing the partial flows in an electrolytic bath to improve the layer thickness distribution on several workpieces attached to a product carrier. The sum of the partial flows on the individual workpieces represents the bath flow, which must be supplied by a rectifier. For this high total current compared to the partial currents, the electrical conductors and contacts from the rectifier to the goods carrier must be of sufficient size. In order to achieve the equalization of the partial currents, the document proposes to insert passive, non-adjustable series resistors into each partial circuit on the product carrier. These series resistors act as current distribution resistors, which are intended to impress the partial current in each workpiece. As the resistance value of each series resistor increases, the impressions of the partial currents increase. However, a complete adjustment of the partial flows is practically not possible. It is also disadvantageous in this case that the electrical energy to be used increases with increasing resistance value. The electrical efficiency of electroplating cells equipped in this way is therefore also unsatisfactory.

Large power losses occur, for example, in the chrome deposition. Here, galvanization is carried out with current densities of up to 200 A / dm ² . In practice, this requires, for example, nominal rectifier currents of 10,000 A (amperes) with a terminal voltage at the rectifier of 10 V (volts). For this total current, all electrical conductors and current contacts, including those of the goods carrier, must be dimensioned sufficiently large. The The effort for the electrical conductors and goods carriers, which usually consist of copper, and for the means of transport that transport the heavy goods carriers through the electroplating system is correspondingly great.

An example of chrome plating is the galvanizing of cylindrical piston rods for shock absorbers. The hard chrome layer to be applied requires a plating current of 800 A per bar at a cell voltage of about 7 V per rod. If there are 10 bars on a product carrier, the rectifier and all current conductors of the bath must be dimensioned for a current supply of at least 8000 A. The rectifier power loss and the electrical power loss in the conductors is around 24 kW at 8000 A. The power loss can be calculated from the empirical values from the electroplating bath power supply. With good approximation it can be assumed that energy losses occur in the rectifier, which result from an internal voltage drop of 2 V multiplied by the rectifier output current. The current conductors are dimensioned so that about 1 V voltage drop occurs across them at nominal rectifier current. This leads to the above-mentioned power loss of 2V x 8000 A = 16 kW for the rectifier and 1 V x 8000 A = 8 kW for the conductors. This performance contrasts with the performance of the electrolytic cell. It is 7 V x 8000 A = 56 kW. The electrical efficiency of this bath power supply is therefore included

56 kW / (24 kW + 56 kW) - 100 = 70 percent.

With four baths of such an electroplating system, the total power loss is 96 kW. These losses do not yet include the additional losses that would occur on the additional power distribution resistors according to the two documents mentioned. Therefore, at least for high electroplating currents, these proposed solutions for the precise electroplating of workpieces are ruled out. It should also be mentioned that the transmission of such high currents to a product carrier requires complex clamp contacts and / or additional water cooling of the contacts. The invention is therefore based on the problem of avoiding the disadvantages of the known devices and methods and, in particular, of finding a method and a device with which a uniform electrolysis power supply, in particular galvanizing power supply, can be made possible for each workpiece or for each electrolysis frame on a goods carrier, the lowest possible energy losses must be accepted and the system equipment should be designed as simply as possible.

The problem is solved by the device according to claim 1 and the method according to claim 11.

The device according to the invention is used for the energy-saving simultaneous electrolytic treatment, in particular electroplating, of several workpieces connected as electrodes, each with the same electrolysis current. The device points

a. at least two electrolytic sub-cells in a bath tank and b. at least one power source for feeding the partial cells with electrolysis current.

The sub-cells in turn point

i. Brackets used for electrical contacting and workpieces held thereon, and ii. at least one counter electrode each.

When the workpieces are galvanized, the workpieces are switched as cathodes and the counter electrodes as anodes; in electrolytic etching / demetallizing, the workpieces are switched as anodes and the counter electrodes as cathodes.

According to the invention, the individual sub-cells are electrically connected in series. In the following, only the application of galvanizing workpieces is considered. Of course, the specified embodiments and examples can also be transferred to the electrolytic etching process by interchanging the polarity of the electrodes and the workpieces.

The series connection of the individual sub-cells ensures that the same workpieces or electroplating frames, each accommodated in a subcell, are automatically flowed through by the same electroplating current. If, for example, a higher contact resistance forms at one of the contact points for one of the workpieces, this resistance determines the electroplating current in all sub-cells. Under these circumstances, either a lower galvanizing current flows through all sub-cells, so that the total galvanizing time must be increased in order to achieve a desired layer thickness on all workpieces, or the galvanizing voltage is increased in order to achieve a constant galvanizing current. The latter procedure is usually used by preferably working with a constant current control and thus generating a constant gating current at the rectifiers used as the current source, which flows through all sub-cells.

The device and the method therefore ensure that the partial flows on the individual workpieces are matched to exactly the same value. The device according to the invention and the method are therefore already compared to the aforementioned known devices and methods according to the

Prefer state of the art. With these, the approximation is only approximate, since the partial currents can only be made more uniform as the series resistor is increased, whereby the partial currents can never be exactly the same size, because the resistances of the electrolytic partial cells each make a different contribution to the total resistance of each individual partial cell deliver.

The invention also has the further advantage that the uniformity Gung the layer thickness of the deposited metal layer does not go hand in hand with a reduced efficiency in metal deposition as in the known devices and methods. While in the known methods and devices an approximate equalization of the partial currents is only made possible by using the series resistors, but the series resistors represent additional current consumers, by means of which the efficiency in the galvanization is reduced, such consumers are not required in the method according to the invention.

In addition, the power supply lines to the anodes and cathodes can be designed to be less complex. All electrical conductors should only be dimensioned so large that a current can flow that corresponds to the current flow for a workpiece. For this purpose, the cables and conductors have a comparatively small cross section and a correspondingly lower weight. The electrical efficiency of a rectifier with the same power is much higher with a large nominal voltage and a small nominal current than with conventional galvanic rectifiers with a small nominal voltage and a large nominal current.

The example of cylindrical piston rods mentioned at the outset is to be used here as a comparison: when carrying out the method according to the invention with the device according to the invention, each product carrier is fed in series with a current of 800 A. The sum of the cell voltages is 10 x 7 V = 70 V, plus a voltage drop at loss resistances on lines and contacts of 2 V. The rectifier power loss is 2 V x 800 A = 1.6 kW. The conductor and contact losses are 2 V x 800 A = 1.6 kW. The total power loss is 3.2 kW and the efficiency is 94.5 percent. With four bathrooms, the total power loss is only 12.8 kW, which is a gain of 83.2 kW compared to the prior art. The savings that result from the transportation of the much lighter goods carriers are not included here.

Another advantage of the invention is that the investment costs for rectifiers for low rated current and high rated voltage are significantly lower are higher than for rectifiers for high nominal current and low nominal voltage with the same power, because the rectifier diodes and the current conductors of the rectifier can only be dimensioned for the low current at high voltage.

Preferred embodiments of the invention are specified in the subclaims.

According to the invention, the anodes of each subcell are electrically connected to the holders for the workpieces and thus to the workpieces of an adjacent subcell. The anodes not connected to holders and the workpieces attached to them and the holders not connected to anodes and the associated workpieces are each connected to one pole of the current sources, so that a closed circuit is created. In the case of two partial times, the anode of the first partial cell is connected to the workpiece of the second partial cell. The anode of the second sub-cell is connected to one pole and the workpiece of the first sub-cell to the other pole of the current source, for example a rectifier.

The workpieces are preferably fastened to goods carriers via the brackets and are electrically insulated from the goods carriers. The product carriers are used to transport the workpieces from one treatment bath to one plating bath electroplating system to the next. The goods carriers are transported from bath to bath by means of suitable transport devices. In order to ensure electrical insulation of the holders and the workpieces from one another, it is particularly expedient to produce the goods carriers from an electrically non-conductive material.

In a first basic circuit arrangement of the invention, for contacting the anodes in the individual sub-cells, rod-shaped anode conductors which project upwards from the anodes and are electrically connected to the anodes and are attached to the product carriers and are electrically insulated from them, which are used to produce an electrical Serve contact to the anode conductors. The contact sockets are designed and arranged so that they come into electrical engagement with the anode conductors when the product carrier is placed on the bath container, or that externally actuated switching devices are provided on the contact sockets, via which electrical contact is made with the anode conductors.

In the circuit arrangement mentioned, the Gaivanisierstrom is from a pole of the power source via electrical connections on goods carrier receptacles arranged on one or both sides on the goods carriers, for example contact pairs, also arranged on the goods carriers and in electrical contact with the workpieces in a first electrolytic subcell and from there to the workpieces in the first subcell. The current then flows from the workpieces through the electroplating liquid and to the anodes. From there, the current reaches the anode conductors and via them to the contact sockets when the product carrier has been placed on the bath container.

The Gaivanisierstrom is then passed in succession through the individual sub-cells via further current bridges which, as individual electrical connections via current conductors insulated from the product carriers, electrically connect the anodes of each sub-cell to the workpieces of the adjacent sub-cell. The current bridges are firmly connected to the brackets. Finally, the Gaivanisierstrom is returned from the anodes in a last sub-cell via further contact sockets and then via current bridges and via further electrical connections arranged on the goods carrier receptacles to the other pole of the current source. The circuit is now closed. The individual sub-cells are electrically connected in series.

Each contact socket on an article carrier assigned to an anode of a partial cell is in each case electrically fixedly connected to the holders of an adjacent partial cell via current bridges. The holders of the first subcell, which are not electrically connected to contact sockets, are electrically connected to the electrical contact of a pair of contacts on the goods carrier via current bridges. this electrical contact is associated with a pole of the power source electrically connected mating contact element of the contact pair on the bath container so that the brackets of the first sub-cell are electrically connected to this pole of the power source when the product carrier is placed on the bath container or when it is lifted from the bath container again be separated.

The anode conductors of the anodes in the last sub-cell on the other side of the row of sub-cells that are not electrically connected to brackets are directly connected to the other pole of the current source. Alternatively, these anode conductors can in turn also be assigned contact sockets on the product carrier, which are electrically connected to an electrical contact of another pair of contacts on the product carrier, this electrical contact being assigned a counter-contact element of the contact pair on the bath container that is electrically connected to the second pole of the power source so that the Anode conductors of the last subcell are electrically connected to this second pole of the power source when the product carrier is placed on the bath container or are separated from it again when it is lifted off the bath container.

In a second basic circuit arrangement, electrical contact pairs are arranged on the product carrier receptacles, which consist of contact elements on the product carriers and corresponding mating contact elements on the bath container. Furthermore, first current conductors are provided between the holders and these contact elements and second current conductors between the anodes and the counter-contact elements of the contact pairs and between the anodes of one of the sub-cells and the current source. The necessary circuit is formed by the following measures:

a. Establishing electrical connections from the anodes of each sub-cell to the holders of respectively adjacent sub-cells when the product carrier is placed on the bath container via the contact pairs on the product carrier receptacles and the aforementioned first and second current conductors; b. Establishing electrical connections from the holders of a first subcell via a first current conductor and one of the contact pairs to the one pole of the current source when the product carrier is placed on the bath container; c. electrical connection of the anodes of a last subcell via a second current conductor to the other pole of the current source when the product carrier is placed on the bath container.

To carry out this variant, ganvanizing current is conducted from a pole of the current source via one of the individual, electrically isolated, individual carrier contacts, one of the first current conductors and the holders to the workpieces in a first subcell. The galvanizing current is conducted from the workpieces in the first partial cell via the electroplating liquid and the anodes of this first partial cell and via one of the second current conductors to the next product carrier contact. The galvanizing current then flows via this contact and via one of the first current conductors to the workpieces in a second subcell and from these workpieces via the electroplating liquid and the anodes in this second subcell and via a further second current conductor to a third product carrier contact. From this third contact, the current flows in the same way via further first current conductors to further workpieces in further partial cells and from the workpieces in the further partial times via the electroplating liquid and the anodes of the further partial cells and via further second current conductors finally back to the current source. In this case, too, the circuit is closed in a series connection.

When the product carrier is placed on the bath container, the product carrier contacts are closed and opened when the product carrier is lifted from the bathroom container.

When the product carrier is placed on the bath container, the electrical connections between the rod-shaped anode conductors which are in electrical contact with the anodes and the workpieces are produced by the Current flows over the current bridges to the contact sockets on the goods carrier and in that the contact sockets on the goods carriers have insertion funnels into which the anode conductors are instructed and come into engagement when the goods carriers are lowered. Alternatively, the connections between the anode conductors and the contact sockets can also be established or separated by externally operated switching devices on the contact sockets.

In a preferred embodiment, a plurality of independent electroplating circuits can also be provided on a product carrier and at least one current source can be assigned to each of these circuits. This embodiment is suitable for both the first circuit arrangement and the second circuit arrangement.

This separation of several circles from one another results in greater flexibility in the production of the coated workpieces. On the one hand, it is not necessary, as when using only one circuit, that the entire goods carrier must always be loaded with workpieces. Workpieces in the individual circuits can also be metallized using different electroplating currents.

Electrical anode insulations are preferably provided in the bath container, by means of which each anode within the bath container is separated from the other anodes in such a way that no galvanizing current can flow directly from anode to anode.

Openings should be contained in the anode insulation so that electrolyte fluid and / or air introduced into the electrolyte fluid via an air injection can be exchanged through these openings between the part-times. However, it is advantageous if electrolyte liquid and / or air is only exchanged between the sub-cells if no gaiting current flows.

For filtration of the liquid and to supplement bath components At least one electrolyte inlet tube or at least one air inlet tube in the bath tank is provided for improved mixing of the electrolyte liquid, the inlet tubes and the inlet tubes having openings from which electroplating liquid or air can flow out and flow into the sub-cells.

Since the terminal voltage at the power sources and in the current-carrying lines is much higher than with conventional systems and will usually be so high that suitable precautionary measures against accidents and improper handling must be taken, personal protective insulation and / or cladding are preferred provide live parts of the electroplating system.

If the method is carried out with the preferred method of constant current control of the current sources, the measurement of the terminal voltages at the current sources can be used to check the function of the individual sub-cells. If a certain value for the terminal voltage at the current source, which indicates an increase in a contact resistance or another defect in the system, is exceeded, suitable measures can be taken to remedy the defect.

On the one hand, the device and the method can be used to coat large-scale individual parts (items to be treated) which are attached to electroplating frames or directly to the product carriers and transported through the immersion bath electroplating system. In addition, electroplating drums with pourable material can be used as workpieces.

The above and following explanations relate to the galvanization of workpieces. Of course, the device and the method can also be used for the electrolytic removal of metal (etching / demetaling) from workpieces. In this case, the embodiments and examples are to be modified accordingly. Both soluble and insoluble anodes can be used as anodes in the electroplating process, or some partial cells can be equipped with soluble and others with insoluble anodes.

The invention is described below with reference to Figures 1 and 2. Show it:

1 shows a schematic cross section through an immersion bath with a plurality of sub-cells in a first circuit arrangement; Figure 2 shows a schematic cross section through an immersion bath with several sub-cells in a second circuit arrangement.

A bath container 1 is shown in cross section in FIG. The bath container 1 can consist of plastic or of insulating-coated metal. In this container there are several electrolytic partial cells 2. Each partial cell consists of a cathode 3, which is formed by the workpiece, and an anode 4. The workpieces are fastened to the product carrier in an electrically insulated manner. The anodes 4 can be both soluble and insoluble anodes. The anodes are arranged in a stationary manner in the bath container 1 in such a way that the anode-cathode spacing required for electroplating results in the electrolytic subcell 2 together with the workpiece to be inserted into it.

Anode conductors 5 are attached to the anodes in an electrically conductive manner. These protrude with their upper end, e.g. is designed as a contact pin, so far beyond the electrolyte mirror 6 that an electrical connection can be made to contact sockets 8 which are insulated on the goods carrier 7 when the goods carrier - as shown here - is placed on the goods carrier receptacles 15 on the bath container 1.

Each anode 4 of a subcell 2 is electrically shielded from the other anodes by means of anode insulation 9 in the electrolyte. The anode insulation 9 consists of an electrically non-conductive material, which also against one chemical attack of the electrolyte is resistant. 1 shows a tubular anode 4 for the galvanization of workpieces in the form of rods. The rod is in the center of the cylindrical anode. It is held in the correct position by pliers 10. The electrically conductive pliers 10 are also used to supply the Gaivanisierstromes to the rod. The pliers are also attached to the goods carrier 7 in an electrically insulated manner.

To initiate the electroplating current on the goods carrier 7, a goods carrier contact 11 is shown schematically, which is also attached to the goods carrier in an electrically insulated manner. The mating contact 12 is arranged stationary on the edge of the bath container 1. The rectifier 13 is used for the galvanizing power supply. The negative pole of the rectifier is connected to the counter contact 12 via the electrical conductor 14. In the figures, all electrical conductors are represented by simple lines. If a transport trolley has placed a goods carrier 7 on the goods carrier receptacles 15 of a bath, the rectifier 13 is electrically connected to the first cathode 3 on the goods carrier via the mating contact 12 and the goods carrier contact 11 and via a current bridge 16. The rectifier 13 forms, together with the electrical conductors, contacts, electrolytic sub-cells and their connections, an electrical series connection. When the rectifier 13 is switched on, a Gaivanisierstrom flows over the workpiece connected as cathode 3 to the anode 4 of the partial cell 2. From the anode 4, it flows via the anode conductor 5 with the contact pin at the upper end of the anode conductor into the contact socket 8. This can also be a mechanical actuated switch be formed. From there, the current flow repeats through the next sub-cell, just as it was described starting from the goods carrier contact 11. The serial galvanizing current flows back from the last anode conductor of the bath to the rectifier 13.

Because the anode conductor 17 is stationary, the current from this last anode conductor can be passed directly from the bath via an electrical conductor and returned to the rectifier 13. In FIG. 1, however, an implementation with a further contact socket 8 and a further contact pair 18 is shown. In this case, all sub-cells are structurally identical. The serial current flow of a galvanizing power supply basically requires that all workpieces on the goods carrier are loaded.

Because the Gaivanisierstrom flows from one electrolytic sub-cell to the next and thus through all sub-cells, all sub-cell currents are exactly the same size. This means that the amount of metal deposited on all workpieces is exactly the same, regardless of the soft cell voltages that occur in the sub-cells. With the same workpiece surfaces, this also results in the same layer thicknesses of the deposited metal.

The galvanizing current is set by the galvanizing system control for the rectifier to the value required for the workpieces and kept constant by a current regulator. The serial galvanizing current described is therefore a constant current. Irregularities in the contacts 8, 11, 12, 18 and the pliers 10 are completely corrected until the nominal voltage of the rectifier is reached. An unusual increase in the terminal voltage of the rectifier for driving the serial Gaivanisierstromes is a sign that at least one effective resistor in the overall circuit has become incorrectly larger. This shows that maintenance is required even before the rectifier nominal voltage is reached as the highest possible terminal voltage for error-free production. Because the serial galvanizing current can be easily regulated and measured using known means of electrical engineering, a safe and precise galvanizing power supply for each individual workpiece on a product carrier is guaranteed. In addition, the entire power supply system can be continuously monitored completely.

The voltages between the anodes and the cathodes of the sub-cells connected in series, ie the cell voltages, add up to the voltage drops across the series-connected resistances of all contacts and current conductors. The sum of all these partial voltages represents the terminal voltage of the rectifier 13. The nominal voltage of the rectifier must be at least as large as this total voltage value, since a control reserve must be provided.

With a large number of sub-cells and / or with high cell voltages, the nominal rectifier voltage reaches a level that requires protective measures against touching the live parts by the personnel. From around 50 V it is necessary to install appropriate personal protection or coverings. To avoid such high rectifier voltages, several serial circuits with a corresponding number of rectifiers per bath and product rack can alternatively be used. However, the least effort for realizing the invention is to work with only one serial circuit per product carrier. In this case, only one rectifier is required for all sub-cells of the bath. It is only to be dimensioned so that the current for a workpiece can flow with a rectifier nominal voltage that corresponds to the number of sub-cells.

All electrolytic sub-cells are in a common electrolyte. Through the series connection of the partial times, a potential occurs between adjacent anodes which is approximately as large as the anode / cathode voltage of a partial cell. This means that a Gaivanisierstrom can flow from one anode to another. The anodes could be metallized on the outside. Anode insulation 9 is used to avoid this possible metallization. They electrically shield one anode from the other.

These anode insulations 9, however, hinder the electrolyte exchange in the sub-cells and possibly also the blowing in of air, which is usually let in globally into the bath tank. The required electrolyte flow and / or the air are therefore introduced into each partial cell space through openings in the anode insulation and / or through pipes 19, 20. If complete electrical insulation of the part-times is to be achieved, these openings are closed during electroplating and temporarily opened for each electrolyte exchange, ie when the sub-cell is de-energized. In the examples in FIGS. 1 and 2, 2 is inserted into each subcell Electrolyte inlet pipe 19, which is provided with holes under the sub-cells 2, introduced electrolyte liquid from below.

An electrolyte overflow from the bath and a circulation pump for electrolyte fluid are not shown in the figures. Likewise, a compressor for the air injection via the air injection tube 20 is not shown. This tube also has openings under the sub-cells for air to flow out. The air serves to move the electrolyte. It is not necessary for the tubes 19, 20 to introduce electrolyte or air into the sub-cells 2 from below. It is sufficient if the tubes 19, 20 are located in the vicinity of the sub-tents with openings which point in the direction of these sub-cells.

The goods carrier 7 has support arms 21 on both sides. A transport device engages in these support arms in order to pull the goods carrier 7 vertically upwards out of the bath and into another bath, e.g. a rinsing bath to transport. In the example shown in FIG. 1, the product carrier itself could consist of an electrical insulator, such as e.g. Ceramic or plastic. However, the contact sockets 8 and the pliers 10 are preferably fastened in an electrically insulated manner to a metal goods carrier.

The contact sockets 8 preferably have an introduction funnel on the underside. Thus, the upper contact pin of the anode conductor 5 is safely instructed when contacting the product carrier into the bath. This contacting is thus established automatically. The movements and forces required for this are derived from the existing processes of the goods carrier. If externally actuated contacts are used for this electrical connection, the movements and forces required for this are to be applied using a mechanism and control (not shown). The contacts 11, 12 can be replaced by a metallic goods carrier and by the goods carrier receptacle 15, in such a way as is known from the plating bath electroplating systems. The metallic goods carrier 7 then lies on the negative pole of the rectifier 13 via the receptacle 15 serving as a contact. Thus, the second goods carrier receptacle 15 can also be used to transmit the Current from the negative pole of the rectifier 13 can be used on the goods carrier 7. This corresponds to a two-sided goods carrier feed-in, which is used when high currents are to be transmitted to the goods carrier via goods carrier receptacles. In these cases, the contact pair 18 with opposing contacts can be dispensed with. As described above, the positive rectifier terminal is then connected directly to the last anode conductor 17.

Another circuit arrangement of the invention is shown in FIG. This differs from the embodiment according to FIG. 1 by the type of current transfers to the goods carrier 7. With the exception of the pliers 10, all contacts are arranged outside the bathroom area. The electrical connections to the anodes 4 are made stationary from each anode conductor 5 directly from the bath container 1. In Figure 2 two independent serial circuits with two rectifiers 13 'and 13 "are shown as an example. However, this is not a condition for the implementation of the invention. Independent serial circuits on a product carrier, however, allow partial loading of the product carrier. So it is possible, only In this case, the other circuit or the other circuits of a product carrier can remain unloaded

For reasons of economy, the principle is that only one rectifier and as many sub-cells as possible should be used for each rectifier, since the costs for protection against excessive contact voltage are significantly lower than the power supply costs for high rectifier currents.

The negative pole of the rectifier 13 'feeds the workpiece connected as the cathode 3 in the subcell 2a via the contact groups 22a. The anode current of sub-cell 2a is fed via anode conductor 5 and via contact group 22b to the cathode of sub-cell 2b. The electrical connection of the conductors 24 to the anode conductor 5 is shown in FIG. 2 in the bathroom for reasons of clarity. In practice, however, this connection is implemented above the electrolyte level 6 in order to avoid corrosion. Insulated conductors 23 are also laid from the contact groups 22 to the pliers 10, the cross-section of which is dimensioned such that they can carry the small serial Gaivanisierstrom. They are attached to the goods carrier in an orderly manner. The serial galvanizing current of the rectifier 13 'then flows successively through the partial electrolytic times 2a to 2d. The current returns from the anode conductor 5 of the subcell 2d to the positive pole of the rectifier 13 '. The second serial electroplating circuit of the rectifier 13 ″ is also formed in the same way.

With this circuit arrangement all described advantages of

Invention too. For the sake of simplifying the drawing, the contact groups 22 in the figures are arranged in the longitudinal direction of the goods carrier. They are supported on a console 25. In practice, however, these contact groups 22 are expediently arranged in the transport direction. The console 25 represents the edge of the bath container 1.

In the galvanizing power supply according to FIG. 1, the goods carrier must be fully equipped with workpieces. In the embodiment according to FIG. 2, this is not necessary for the serial circuit according to the invention if further electrical switches are inserted. These switches are arranged in the stationary electrical lines 24 so that they electrically bridge the sub-cells 2 that have not been loaded with a workpiece. The switches, e.g. electrical contactors, can be actuated by control signals given by the electroplating system control.

The invention can also be used in the electrolytic treatment of flat workpieces such as printed circuit boards, in which a very uniform layer thickness is required from printed circuit board to printed circuit board and also over the entire surface of a printed circuit board. The device and the method according to the invention are also advantageously used in the electroplating of bulk material in drums. If two drums are arranged on a drum carrier, these can be electrically connected in series for the purposes of the invention. The serial Gaivanisierstrom is on the two drum carrier took headed through the drum. Two sub-cells are formed in the electrolytic bath. In this case, the electroplating rectifier can only be dimensioned for the current of a drum, but with double voltage. This circuit shows that the Gaivanisierstrom is exactly the same size on both drums.

All disclosed features and combinations of the disclosed features are the subject of this invention, unless they are expressly designated as known.

Reference symbol list:

1 bath container

2 electrolytic sub-cells

3 cathode (workpiece)

4 anode (counter electrode)

5 anode conductors with contact pin

6 electrolyte mirror

7 product carriers

8 contact socket

9 anode insulation

10 pliers

11 Product carrier contact

12 counter contact

13 current source (rectifier)

14 electrical conductors

15 goods carrier holder

16 power bridge

17 last anode conductor

18 contacts

19 electrolyte inlet tube

20 air inlet pipe

21 support arm

22 contact group

23 insulated conductors on the goods carrier

24 insulated conductors at the bathroom

25 console

Claims

Claims:

1. Device for the energy-saving simultaneous electrolytic treatment of several workpieces connected as electrodes, each with the same electrolysis current

a. at least one power source and b. at least two electrolytic sub-cells in a bath tank, which i. Brackets for the workpieces used for electrical contacting and ii. each have at least one counter electrode,

characterized in that the individual sub-cells (2) are electrically connected in series.

2. Apparatus according to claim 1, characterized in that the counter electrodes (4) of each sub-cell (2) with the brackets (10) for the workpieces (3) are each electrically connected to an adjacent sub-cell and the counter electrodes not connected to brackets and not Brackets connected to counter electrodes are each connected to one pole of the current sources (13), so that a closed circuit is created.

3. Device according to one of the preceding claims, characterized in that goods carriers (7) for transporting the workpieces (3) from one treatment bath of an immersion bath electrolysis system to the next are provided and that the holders (10) for the workpieces are fastened to the product carriers and are electrically insulated from the goods carriers.

4. The device according to claim 3, characterized in that on the counter electrodes (4) projecting upwards, rod-shaped, with the counter electrodes elec- Trically connected counter-electrode conductors (5) and on the product carriers (7) and electrically insulated from these contact sockets (8) are arranged, which serve to make electrical contact with the counter-electrode conductors (5) and are designed and arranged so that they touch down the goods carrier on the bath container (1) can come into electrical engagement with the counter electrode conductors, or that externally operated switching devices are provided on the contact sockets, via which electrical contact with the counter electrode conductors can be established.

5. The device according to claim 4, characterized in

a. that each contact socket (8) assigned to a counter electrode (4) of a sub-cell (2) on a product carrier (7) is electrically connected to the brackets (10) of an adjacent sub-cell via current bridges (16), b. that the holders of a first subcell, which are not electrically connected to contact sockets, are electrically connected to the electrical contact (11) of a pair of contacts on the goods carrier via current bridges, the electrical contact (11) being a mating contact element (12) electrically connected to a pole of the current source (13) the pair of contacts on the bath container (1) is assigned such that the holders of the first subcell can be electrically connected to the power source when the product carrier is placed on the bath container, and c. that the counterelectrode conductors (17) of the counterelectrodes (4) which are not electrically connected to brackets are electrically connected in a last subcell to the other pole of the current source.

6. The device according to claim 3, characterized in that

a. electrical contact pairs (22a, 22b, 22c, 22d), consisting of contact elements on the product carriers (7) and corresponding mating contact elements on the bath container (1), b. Current conductor (23) between the brackets (10) and the contact ment and c. Current conductors (24) are provided between the counter electrodes (4) and the counter contact elements of the contact pairs (22b, 22c, 22d) and between the counter electrodes of one of the sub-cells (2d) and the current source (13), i. wherein electrical connections from the counter electrodes of each partial cell (2a, 2b, 2c) to the holders of respectively neighboring partial cells (2b, 2c, 2d) when the product carrier (7) is placed on the bath container (1) via the contact pairs (22b, 22c, 22d ) and the current conductors (23) and (24) can be produced, ii. electrical connections from the holders of a first subcell (2a) via the current conductors (23) and the contact pair (22a) to the one pole of the current source when the product carrier is placed on the bath container, and iii. and finally the counter electrodes of a last sub-cell (2d) are electrically connected to the other pole of the current source (13) via the current conductors (24).

7. Device according to one of claims 3 to 6, characterized in that a plurality of independent electrolysis circuits are provided on a product carrier (7) and these are each assigned at least one current source (13).

8. Device according to one of the preceding claims, characterized in that each counter electrode (4) within the bath container (1) is separated from the other counter electrodes by electrical counter electrode insulation (9) in such a way that no electrolysis current can flow directly from counter electrode to counter electrode .

9. Device according to one of the preceding claims, characterized in that at least one electrolyte inlet tube (19) and / or at least one air inlet tube (20) are provided in the bath tank (1), the inlet tubes and the inlet tubes having openings from which electrolyte liquid and / or Air can flow out and flow into the sub-cells (2).

10. Device according to one of the preceding claims, characterized in that personal protective insulation and / or cladding of the current-carrying parts of the electrolysis system are provided.

11. A method for the energy-saving simultaneous electrolytic treatment of several workpieces with the same electrolysis current, in which the workpieces are arranged in at least two electrolytic sub-cells in a bath container containing an electrolyte liquid and switched as electrodes, the sub-cells serving at least one counter electrode and for electrical contacting Have brackets and the workpieces held thereon, and in which the sub-cells are fed by at least one power source,

12. The method according to claim 11, characterized in that goods carriers (7) for transporting the workpieces (3) from a treatment bath of an immersion bath to the next are provided and the workpieces are fastened to the goods carriers with holders (10) and are electrically insulated from the goods carriers .

13. The method according to any one of claims 11 and 12, characterized in that

a. Electrolysis current from one pole of the power source (13) via electrical connections on goods carrier receptacles (15) arranged on one or both sides of the product carriers (7) to the product carriers likewise arranged and with the workpieces (3) in a first electrolytic sub-cell (2) current bridges (16) in electrical contact and conducted from there to the workpieces in the first subcell will, b. the electrolysis current is then successively passed through the individual sub-cells via further current bridges (16) which, as individual electrical connections via current conductors insulated from the product carriers, electrically connect the counterelectrodes (4) of each sub-cell to the workpieces of the adjacent sub-cell, and c. the electrolysis current is then returned from the counter electrodes in a last subcell via further electrical connections to the other pole of the current source.

14. The method according to claim 13, characterized in that the electrical connections to the product carrier receptacles (15) when placing the product carrier (7) on the bath container (1) via contact pairs (11, 12, 18) and when lifting the product carrier from the bath container be separated.

15. The method according to any one of claims 13 and 14, characterized in that electrical connections between the counter electrodes (4) in electrical contact, upwardly projecting, rod-shaped counter electrode conductors (5) and the workpieces (3) via the current bridges (16) by placing the product carriers (7) on the bath container (1) and separating them from the bath container when lifting, by electrically connecting contact sockets (8) with funnels to the current bridges into which the counterelectrode conductors engage, or by making the connections via contact sockets (8) are manufactured or separated by externally operated switching devices on the contact sockets.

16. The method according to any one of claims 11 and 12, characterized in that

a. Electrolysis current from one pole of the power source (13) via a goods carrier contact (22a) of several individual goods carrier contacts (22a, 22b, 22c, 22d) that are electrically insulated from one another on a receptacle (15) for the goods carrier (7) and via a first current conductor ( 23) is guided to workpieces (3) in a first subcell (2), b. the electrolysis current is conducted from the workpieces in the first subcell via the counter electrodes (4) of this first subcell and via a current conductor (24) to the next product carrier contact (22b) and c. the electrolysis current is conducted from there in the same way via further current conductors (23) to further workpieces in further partial times and from the workpieces in the further partial cells via the counter electrodes of the further partial cells via further current conductors (24) back to the current source.

17. The method according to claim 16, characterized in that the product carrier contacts (22a, 22b, 22c, 22d) are closed when the product carrier (7) is placed on the bath container (1) and opened again when the product carrier is lifted off the bath container.

18. The method according to any one of claims 11 to 17, characterized in that each counter electrode (4) within the bath container by electrical counter electrode insulation (9) is separated from the other counter electrodes so that no Gaivanisierstrom can flow directly from counter electrode to counter electrode.

19. The method according to claim 18, characterized in that electrolyte fluid and / or air introduced into the electrolyte fluid via an air injection (20) is exchanged between the sub-cells (2) through openings in the counter-electrode insulation (9).

20. The method according to claim 19, characterized in that electrolyte liquid and / or air between the sub-cells (2) is only exchanged when no electrolysis current flows.

21. The method according to any one of claims 11 to 20, characterized in that the current sources (13) are operated under current control.

22. The method according to any one of claims 11 to 21, characterized in that the terminal voltages at the current sources (13) are monitored and used to check the function of the individual sub-cells (2).

23. The method according to any one of claims 11 to 22, characterized in that electroplating drums with pourable, to be electroplated material to be treated are used as workpieces (3).