EP2660363A2 - Adjustable anode - Google Patents

Abstract

Device for galvanically coating a workpiece, comprises (a) a first anode segment and a second anode segment, (b) a positioning device for influencing the position of the anode segments for adjusting the anode segments to the geometry of the workpiece, and (c) at least one hinge for connecting one anode segment with the further anode segment.

Description

The invention relates to a device for the galvanic coating of a workpiece, in particular an adjustable anode.

Such devices are used for example for coating gravure cylinders or other machine parts.

Anodes are known which can be used for workpieces with different geometries. However, these usually have a poor galvanic coating efficiency, resulting in long coating times and high energy consumption.

It is an object of the invention to provide a novel apparatus for electroplating.

This object is achieved by the subject matter of claim 1.

Such a device allows good efficiency for workpieces with different geometries.

• Fig. 1 einen Querschnitt durch eine Galvanisiervorrichtung mit einer Positioniervorrichtung, einer Anode und einem in der Galvanisiervorrichtung angeordneten Werkstück,
• Fig. 2 einen Querschnitt durch die Galvanisiervorrichtung aus Fig. 1 mit einem Teilschnitt durch die Positioniervorrichtung,
• Fig. 3 eine raumbildliche Darstellung der Galvanisiervorrichtung aus Fig. 1 mit einem Werkstück mit kleinem Durchmesser,
• Fig. 4 eine raumbildliche Darstellung der Galvanisiervorrichtung aus Fig. 1 mit einem Werkstück mit großem Durchmesser,
• Fig. 5 einen vergrößerten Ausschnitt der Anode aus Fig. 1,
• Fig. 6 eine raumbildliche Darstellung der Galvanisiervorrichtung aus Fig. 1 ohne Werkstück,
• Fig. 7 einen vergrößerten Ausschnitt der Positioniervorrichtung aus Fig. 1 ohne Abdeckung,
• Fig. 8 eine raumbildliche Darstellung der Galvanisiervorrichtung aus Fig. 1 ohne Abdeckung der Positioniervorrichtung,
• Fig. 9 bis Fig. 11 schematische Darstellungen der Einstellung der Anode aus Fig. 1 für unterschiedliche Werkstücke und Darstellung des Wirkungsgrads,
• Fig. 12 bis Fig. 14 schematische Darstellungen der Einstellung einer starren Anode aus dem Stand der Technik für unterschiedliche Werkstücke und Darstellung des Wirkungsgrads,
• Fig. 15 eine schematische Darstellung einer zweiten Ausführungsform einer Galvanisiervorrichtung mit einer Positioniervorrichtung, einer Anode und einem in der Galvanisiervorrichtung angeordnetem Werkstück

Further details and advantageous developments of the invention will become apparent from the hereinafter described and illustrated in the drawings, in no way as a limitation of the invention to be understood embodiments, and from the dependent claims. It shows

• Fig. 1 a cross section through a galvanizing with a positioning device, an anode and a arranged in the galvanizing workpiece,
• Fig. 2 a cross section through the galvanizing from Fig. 1 with a partial section through the positioning device,
• Fig. 3 a spatial representation of the galvanizing from Fig. 1 with a workpiece of small diameter,
• Fig. 4 a spatial representation of the galvanizing from Fig. 1 with a large diameter workpiece,
• Fig. 5 an enlarged section of the anode Fig. 1 .
• Fig. 6 a spatial representation of the galvanizing from Fig. 1 without workpiece,
• Fig. 7 an enlarged section of the positioning of Fig. 1 without cover,
• Fig. 8 a spatial representation of the galvanizing from Fig. 1 without cover of the positioning device,
• Fig. 9 to Fig. 11 schematic representations of the setting of the anode off Fig. 1 for different workpieces and representation of the efficiency,
• FIGS. 12 to 14 schematic representations of the setting of a rigid anode of the prior art for different workpieces and representation of the efficiency,
• Fig. 15 a schematic representation of a second embodiment of a galvanizing with a positioning device, an anode and arranged in the galvanizing workpiece

Hereinafter, the same or equivalent components are denoted by the same reference numerals or the same reference numerals and apostrophes and not described several times.

Structure of the electroplating device

Fig. 1 and Fig. 2 They have two cross sections through a galvanizing 10. It has a trough 12, in which a galvanic bath 13 (electrolyte with additives) is located, the surface 13 'is located. A workpiece (eg rotogravure cylinder or machine part) 14 is located partially or completely in the galvanic bath 13 and is preferably mounted in such a way that it rotates 18 can perform about a rotation axis 16. An anode 30 at least partially surrounds the workpiece 14, and in the present embodiment has the shape of an upwardly open channel or U-shaped cross section. In electroplating, a section perpendicular to the axis of rotation 16 of the workpiece 14 is usually regarded as a cross section. The anode 30 has a first anode segment 31 and a second anode segment 32, which are connected by a hinge 35. There is no further anode segment between the first anode segment 31 and the second anode segment 32. In the present embodiment, the hinge 35 is a hinge joint, but it could, for example, also have one or more ball joints. The anode segments 31, 32 run at least partially alongside each other in the longitudinal direction or at least partially parallel to one another in the longitudinal direction, so that at least partially a plurality of anode segments 31, 32 are present in cross section.

A positioning device 60 has a first arm 61 and a second arm 62, wherein the first arm 61 is connected via a hinge 38 with the first anode segment 31 and the second arm 62 via a hinge 39 with the second anode segment 32. The positioning device 60 allows a linear movement of the first arm 61 along a linear axis 63 and a linear movement of the second arm 62 along a linear axis 64, see. Fig. 2 ,

A schematically indicated current source (or voltage source) 20 is connected with its negative pole via a line 21 to the workpiece 14 and with its positive pole via lines 22 to the anode segments 31, 32 or to the anode 30.

functionality

In the case of electroplating, a current flows between the anode 30 and the workpiece 14, thereby causing deposition of a metal (e.g., copper, chromium) or metal alloy (e.g., copper, chromium) contained in the plating bath 13.

Nickel-phosphorus, bronze) with metallic and / or non-metallic additives on the workpiece 14. The galvanic bath 13 preferably covers at least the anode 30, to avoid efficiency losses. The rotation 18 of the workpiece 14 results in a uniform coating.

The distance D of the anode 30 to the workpiece 14 is important to the success of the electrodeposition. The distance D must be at least as large at all points that the workpiece has no contact with the anode 30. On the other hand, a large distance D between the anode 30 and the workpiece 18 requires a high voltage of the current source 20 to achieve the required current density. A small distance allows the use of a smaller voltage, and this saves energy.

So far, 14 different, adapted to the workpiece 14 anodes are usually used depending on the workpiece to be coated.

At the anode 30 off Fig. 1 It is possible to change the position of the anode 30 and the relative position of the first anode segment 31 to the second anode segment 32 via the positioning device 60 to allow an adaptation of the anode segments 31, 32 to the geometry of the workpiece 14. The average distance between the workpiece 14 and the anode 30 is thus reduced by a suitable adjustment of the positioning device 60 with respect to the workpiece 14 to be coated. By the hinge joint 35 is relative movement of the anode segments to each other only a rotational movement and no translational movement possible, wherein the anode segments 31, 32 can also be moved translationally as a whole.

Fig. 3 shows the adjustment of the anode 30 for a workpiece 14 with a relatively small diameter. The first anode segment 31 and the second anode segment 32 have been moved toward one another by the positioning device 60, cf. Linear movement 63, 64 off Fig. 1 ,

Fig. 4 shows an adjustment of the anode 30 for a workpiece 14 with a relatively large diameter. The first anode segment 31 and the second anode segment 32 are opened wide relative to each other to provide space for the large workpiece 14. These are - as in Fig. 1 - the first arm 61 and the second arm 62 have been moved down and away from each other, as indicated by the arrows 63, 64.

Structure and function of the anode

Fig. 5 shows a detailed view of the first anode segment 31, and Fig. 6 shows the complete anode 30. The first anode segment 31 and the second anode segment 32 are constructed basically the same, so that the following description of the first anode segment 31 correspondingly applies to the second anode segment 32, unless explicitly noted differences.

The first anode segment 31 has ribs (reinforcing ribs) 40 fixed to a profile bar 42. The profile bar 42 preferably extends over the entire length of the anode 30, but it may be z. B. also be formed in several pieces. He has z. B. a substantially rectangular profile. The ribs 40 have on their side facing the workpiece 14 a predetermined profile 45 to which the actual anode surface 41 is fixed, in Fig. 5 as a thick black line and in Fig. 6 is shown schematically over the entire surface. The attachment of the anode surface 41 to the ribs 40 is effected for example by welding or soldering. The anode surface 41 is usually made of an expanded metal, as shown in FIG Fig. 6 with 41 'is indicated on a portion, but it can, for. B. also be formed over the entire surface.

On one side of the profile bar 42, ribs 50 are fixed, to which a guide 55 for an anode panel 53 is attached. The guide 55 preferably has two profiled bars 51, 52 which extend in the longitudinal direction at least over part of the anode 30. The anode panel 53 is slidably disposed on the guide 55 in the manner of a carriage. The anode panel 53 extends in cross-section from the guide 51, 52 along the anode surface 41 to the hinge 35th

The materials used for the anode 30 depend on the galvanic bath 13 to be used, cf. Fig. 1 , In a preferred embodiment, the ribs are 40, 50 and the anode surface 41 formed of titanium. Preferably, the profile bar 42 is formed of copper and surrounded by a layer 43 of titanium. Since copper conducts electricity better than titanium, the current can be well distributed over the profile bar 42 and fed to the anode surface 41.

The anode panel 53 is preferably made of an electrically non-conductive material such. As plastic is formed and is pushed into the region of the associated axial end of the workpiece 14 to reduce in this area the electrodeposition, which is otherwise particularly heavily coated due to the high field strength occurring there, which is e.g. in gravure is not desired.

The hinge 35 is preferably formed by a bore in the ribs 40, in which a sliding bushing 36 (eg made of plastic) is pressed. In the sliding bush 36, a shaft 37 is inserted, which is preferably secured against axial displacement. Preferably, the shaft 37 extends over the entire length of the anode 30 or at least over half of the anode 30, to effect an additional stiffening of the anode 30. The hinge 35 is disposed between the first anode segment 31 and the second anode segment 32 and connects them in an articulated manner.

Preferably, the anode segment 31, 32 is stable in itself, so that at a predetermined position of the arms 61, 62, the position of the joint 35 and the anode segments 31, 32 is defined.

In this embodiment, the hinge 35 is not electrically conductive or poorly conductive through the sliding bush 36 made of plastic, so that both anode segments 31, 32 to the power source 20 from Fig. 1 must be connected. Particularly in the case of anodes 30 having more than two anode segments 31, 32, however, it is advantageous to electrically connect the middle anode segments via electrically conductive joints 35 or additional cable bridges (not shown) in order to ensure good current supply even in these middle anode segments.

As in Fig. 6 can be seen, the anode has 30 Kontaktierbereiche 46 for electrical connection of the power source 20 from Fig. 1 with the anode 30. The Kontaktierbereiche 46 preferably have threaded holes 47 which extend into the profile bars 42 into it. Electrical lines 22 are connected via connectors 23 with the Kontaktierbereichen 46. The plugs 23 are preferably provided with a thread and a fluid-tight seal in order, after the plug 23 has been screwed in, to fill the plating bath 13 (without risk of damage or coating). Fig. 1 ) to allow above the Kontaktierbereichs 46. Unused threaded holes 47 are preferably also sealed.

Structure and function of the positioning device

Fig. 7 shows the part of the positioning device 60 which is connected to the first arms 61. The other part for the arms 62 is basically the same, and the description applies accordingly, unless it is explicitly pointed to differences. Also, the arms 61 and the arms 62 are basically the same, so that only one arm is described. The two first arms 61 in this embodiment have a distance of about 650 mm, this being dependent on the geometry of the workpieces 14 to be coated.

The first arm 61 is rigidly connected to a rod 71. In this embodiment, the first arm 61 is fixedly connected to a clamping piece 66, for. B. by welding, and the clamping piece 66 is fixedly connected to the rod 71, z. B. by Schraubklemmung. The first arm 61 has the shape of an inverted L, so that it over the edge of the tub 12 (FIG. Fig. 1 ) can grab. A block (bearing block) 73 shown only in half has a rail 72 which forms a guide 70 together with the rod 71. In this embodiment, the guide 70 is a linear guide, which allows a linear movement of the rods 71, as indicated by the arrows 63. The angle α between the vertical line 74 and the rod 71 is preferably not equal to 0 ° and not equal to 90 °, ie neither horizontal nor vertical, more preferably in the range of 10 ° to 80 °, particularly preferably in the range of 15 ° to 60 °. This slope causes a movement the rod 71 in one direction, a movement of the arm 61 inwardly and upwardly, and the reverse movement of the rod 71 causes a movement of the arm 61 downwardly and outwardly. About the joints 38, this movement is transmitted to the anode 30 and to the first anode segment 31.

Preferably, the rods 71 are automatically adjustable. For this purpose, a control device 88 and a controllable drive 80 are provided, wherein the drive 80 drives a gear wheel 82 via a - not visible from this perspective - connected to the drive 80 gear wheel controllable. The gear 82 is connected to gears 86 via a shaft 84, and the gears 86 drive the rods 71. For this purpose, the rods 71 are preferably designed as racks with corresponding teeth 87, wherein the guide 70 and the drive 86, 87 of the rods 71 can also be designed spatially separated.

As the drive 80, an electronically commutated DC motor is preferably used, preferably via a planetary gear drive gear 82 drives. But there are also other drives possible.

The drive 80 is preferably assigned an absolute value transmitter 89. With the aid of the absolute value generator 89, it is possible, for example, to move the rod 71 into an end position (for example the lowest position), wherein the reaching of the end position, for example, can be detected via a motor current limit. Subsequently, the desired position for the anode 30 can be precisely adjusted from this defined starting position with the aid of the absolute value transmitter 89.

Preferably, the blocks 73 are provided with attachment means 75 for attachment of the positioning device to the tub 12 Fig. 1 or provided on a machine frame.

• A) Ein den Durchmesser des zu beschichtenden Werkstücks charakterisierender erster Wert wird eingegeben, z.B. manuell über eine Eingabekonsole oder automatisch über eine Vermessung des Werkstücks;
• B) die Steuervorrichtung 88 ermittelt aus dem ersten Wert eine Ziel-Position für den Antrieb 80;
• C) die Steuervorrichtung 88 steuert den Antrieb 80 derart, dass die Ziel-Position erreicht wird.

The positioning device 60 is preferably designed to carry out the following steps:

• A) A first value characterizing the diameter of the workpiece to be coated is input, eg manually via an input console or automatically via a measurement of the workpiece;
• B) the controller 88 determines from the first value a target position for the drive 80;
• C) The control device 88 controls the drive 80 such that the target position is reached.

• A) Die Anodensegmente 31, 32 werden in eine erste Endposition bewegt, um eine definierte Ausgangsposition zu erzeugen, z.B. durch ein Bewegen der ersten Arme 61 und zweiten Arme 62 in die jeweils unterste oder oberste Endposition;
• B) folgende Ziel-Positionen werden mit Hilfe des Absolutwertgebers 89 ausgehend von der Ausgangsposition angesteuert.

The positioning device 60 is preferably designed to carry out the following steps:

• A) The anode segments 31, 32 are moved to a first end position to produce a defined home position, eg, by moving the first arms 61 and second arms 62 to the lowermost or uppermost end positions, respectively;
• B) following target positions are controlled by means of the absolute encoder 89 starting from the starting position.

In Fig. 8 For example, the left block 73 is fully illustrated, and the right block 73 is omitted.

FIGS. 9, 10 and 11 show possible settings of the anode 30 for workpieces 14 with different diameters. By simulation, it was determined where the effectiveness ranges of the anode 30 lie. A high efficiency is indicated in the figures with "+", an average effectiveness with "0" and a bad effectiveness with "-". As can be seen, the axis of rotation 16 is in each case at the same height, since the clamping of the workpieces 14 usually takes place always at the same point of the galvanic coating system 10. Due to the oblique arrangement of the rods 71, the anode 30 of Fig. 9 to Fig. 11 both folded and moved to the upper joints 38, 39 upwards. This leads to a high efficiency of the anode 30 for the different diameters. In Fig. 9 the hinge 35 is opened so far that the angle between the anode surface of the first anode segment 31 and the Anode surface of the second anode segment 32 is about 180 °. In Fig. 11 the angle is about 90 °.

FIGS. 12, 13 and 14 show a rigid anode 130 of the prior art. Due to the solid V-shaped form of the anode 130, a coating of workpieces with different diameters is possible, wherein the area effective for the coating with the designation "+" is significantly lower than that of the anode 30 Fig. 1 ,

It was not foreseeable for the skilled worker that already two anode segments 31, 32 according to Fig. 9 to Fig. 11 allow a good adaptation of the geometry to different diameters of the workpiece 14. Although, in principle, additional anode segments allow a more precise adaptation of the anode 30 to the geometry of the workpiece 14, they also lead to a considerably greater effort for the positioning.

It was even less predictable that a pure linear guide 70 ( Fig. 7 ) of the arms 61, 62 for adjusting the anode 30 allows such a good adaptation of the geometry to different diameters. Such a linear guide 70 enables a simple construction of the positioning device 60.

Shape of the anode surface

As in Fig. 9 to Fig. 11 can be seen, the anode surface 41 of the anode segments 31 and 32 respectively in cross section has a shape that is neither quite straight nor evenly curved. The cross section of the anode surface 41 is curved in a first (middle) region 100, and it is surrounded on both sides by regions 101, 102 with a smaller curvature than in the region 100. The term curvature also includes anode surfaces 41, which have a series of straight sections connected by creases, as a result of which also leads to a corresponding curvature of the anode surface 41. The outer regions 101, 102 preferably pass in a subarea facing away from the region 100 in straight lines (curvature 0). Simulations have shown that with such Anode surface, the average distance between the workpiece 14 and the anode surface 41 for different diameters of the workpiece 14 can be kept low.

Anodes with more than two anode segments

Fig. 15 12 schematically shows an alternative embodiment for an anode 30, wherein on the left side a setting for a workpiece 114 with a large diameter (eg 335 mm) and on the right side a setting for a workpiece 114 'with a small diameter (eg 230 mm) is shown is. The anode 30 has, in addition to the anode segments 31, 32, a middle third anode segment 110 which is connected via a joint 35 'to the anode segment 31 and via a joint 35 "to the anode segment 32. Because of the middle segment 110, it is advantageous to position and position (orientation) of the anode segments 31, 32 in order to clearly define the position and position of the anode segment 110. In the present exemplary embodiment, this is achieved by the position of the anode segments 31, 32 at respectively two points 38, 115 and 39, respectively , 115 'is set.

A definition of the position of the anode segments 31, 32 at only one point 38 or 39 could theoretically lead to a defined position of the central anode segment 110 due to gravity. However, this is not sure because of the friction.

A linkage (coupling rod) 122 is fixed between a fixed attachment point (support) 120 and the joint 38, and a linkage (coupling rod) 123 is fixed to a fixed attachment point (support) 121 and the joint 115. Via the linkage 122, 123 and 122 ', 123', the position and position of the anode segments 31, 32, 110 can be clearly defined. For this purpose, the linkage 122, 122 'may be connected to a controllable drive 80, cf. Fig. 7 ,

The anode segments 31, 32 have a first curvature in cross section on the side facing the anode segment 110, and a second curvature on the side remote from the anode segment 110, wherein the first curvature is greater than the second curvature is. The anode segment 110 has a substantially constant curvature, but it may also have regions with different curvatures, wherein it is preferably mirror-symmetrical to the vertical central axis.

Naturally, many modifications and modifications are possible.

Thus, the guide 71, 72 for the arms 61, 62 (FIG. Fig. 7 and Fig. 15 ) can also be formed as a curved guide, in order to enable, for example, in other geometries of the anode segments 31, 32, an improved positioning of the anode.

The joints 35, 38, 39, 35 ', 35 ", 115, 115' preferably extend in each case parallel to the axis of rotation 16. With special geometries of the workpiece 14, embodiments are also possible in which at least some of these joints are not parallel to the axis of rotation 16 runs.

Only a first arm 61 and a second arm 62 may be used.

Between the first anode segment 31 and the second anode segment 32, an anode segment 110 or else a plurality of anode segments 110 can be provided.

The anode surfaces 41 of the anode segments 31, 32, 110 are in cross section on their during the coating the workpiece 14 side facing in partial areas (eg 100, 101, 102 in Fig. 9 ) at least partially concave and preferably in subregions (eg 101, 102 in Fig. 9 ) at least partially straight. It is also possible for the anode segments 31, 32, 110 to be in partial areas (eg 101, 102 in FIG Fig. 9 ) at least partially convex.

When using other joints 35 and / or at least three anode segments 31, 32, 110 is a relative movement of the anode segments 31, 32, 110 to each other possible, which also contains a translational component in addition to a rotational component.

The positioning device 60 may be formed in a simplified embodiment without a drive 80, and manual adjustment may be provided.

Claims (15)

Device (10) for the galvanic coating of a workpiece (14), which comprises: A plurality of anode segments (31, 32, 110) comprising a first anode segment (31) and a second anode segment (32); a positioning device (60) which is adapted to influence the position of the anode segments (31, 32, 110) in order to adapt them to the geometry of the workpiece (14); and at least one joint (35, 35 ', 35 "), via which one anode segment (31, 32, 110) is connected to another anode segment (31, 32, 110) and which acts as a relative movement of the two via the joint (35 , 35 ', 35 ") connected anode segments (31, 32, 110) allows each other a rotational movement. The device of claim 1, wherein the hinge (35) connects the first anode segment (31) to the second anode segment (32). The device of claim 1, wherein the first anode segment (31) is connected to the second anode segment (32) via at least a third anode segment (110). Device according to one of claims 1 to 3, wherein the positioning device (60) at least with the first anode segment (31) and the second anode segment (32) in each case at at least one predetermined connection point (38, 39, 115, 115 ') is connected. Device according to Claim 4, in which the positioning device (60) is designed to fix at least the position of the at least one predetermined connection point (38, 39, 115, 115 '). Device according to one of the preceding claims, wherein the anode segments (31, 32, 110) at least partially an anode surface (41), whose cross-section has the shape of a curved curve. The device of claim 6, wherein the cross section of the anode surface (41) has a first region (100) with a first curvature and a second region (101, 102) with a second curvature, wherein the first curvature is greater than the second curvature. Apparatus according to claim 7, wherein the first region (100) is surrounded on both sides by a second region (101, 102). Device according to one of the preceding claims,
wherein the positioning device (60) comprises at least one first arm (61) connected to the first anode segment (31), and
wherein the positioning device (60) comprises at least one second arm (62) connected to the second anode segment (32). The apparatus of claim 9, wherein the positioning device (60) comprises at least two linear guides (70), and wherein the first arm (61) and the second arm (62) are each linearly movable along one of the linear guides (70) Linear guides (70) preferably have a rack (71). Apparatus according to claim 10, wherein in the operative position of the device (10) the linear guides (70) extend in a direction which is neither vertical nor horizontal, the angle (α) between the direction of the linear guide (70) and the vertical direction (74) is preferably in a range of 15 ° to 60 °. Device according to one of the preceding claims, wherein the anode segments (31, 32, 110) on their during the coating the Workpiece (14) side facing at least partially concave. Device according to one of the preceding claims, wherein the positioning device (60) is adapted to cause a relative movement of the anode segments to each other, wherein this relative movement includes at least one rotational component. Device according to one of the preceding claims, wherein the positioning device (60) comprises a control device (88) and at least one controllable by the control device drive (80) for influencing the position of the anode segments (31, 32, 110), wherein the positioning device (60 ) is adapted to carry out the following steps: A) A first value characterizing the diameter of the workpiece to be coated is entered; B) the controller (88) determines from the first value a target position for the drive (80); C) the control device (88) controls the drive so that the target position is reached. Device according to one of the preceding claims, in which the positioning device (60) comprises a control device (88), at least one drive (80) controllable by the control device for moving the anode segments (31, 32, 110) to a target position and an absolute value transmitter (89). wherein the positioning device (60) is designed to carry out the following steps: A) the anode segments (31, 32, 110) are moved to a first end position to produce a defined home position; B) following target positions are controlled by means of the absolute encoder (89) starting from the starting position.

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