WO1992018669A1

WO1992018669A1 - Galvanisation device for plate-like workpieces, especially printed circuit boards

Info

Publication number: WO1992018669A1
Application number: PCT/DE1992/000288
Authority: WO
Inventors: Daniel Hosten
Original assignee: Siemens Aktiengesellschaft
Priority date: 1991-04-12
Filing date: 1992-04-09
Publication date: 1992-10-29
Also published as: DE59202882D1; ATE125001T1

Abstract

The workpieces to be galvanised are conveyed along a horizontal path through an electrolyte in which there is at least one anode (A1). The cathodic contact for the workpieces conveyed is provided by rotary contact members (K1), e.g. contact wheels. Undesired metal deposits on the contact members (K1) are removed electrolytically according to the present invention. To this end, the contact members (K1) are anodically connected in relation to at least one auxiliary cathode arranged in the electrolyte, whereby screen (As1) preferably forms a demetallisation chamber (EK1) in which the contact members (K1) and the auxiliary cathode (H1) are located.

Description

Electroplating device for plate-shaped workpieces, especially printed circuit boards

Electroplating devices are known in which plate-shaped workpieces, such as. B. circuit boards, are transported in a horizontal pass through an electrolyte, the feed and cathodic contacting of the workpieces passing through being carried out in pairs by means of contacting wheels arranged along one side of the conveying path in the electrolyte. To protect the contacting wheels from the electrolyte, shields extending in the direction of passage are provided with sealing strips resting on the respective workpiece (DE-A-32 36 545).

In the case of the electroplating device described above, the use of a shield cannot completely prevent the electrolyte from accessing the lateral contacting area of the workpieces and the contacting wheels. As a result of this incomplete shielding, spongy metal deposits occur in the contact area, a rapid deterioration of the rolling contacts and unfavorable layer thickness distributions of the electrodeposited layers or a strong scattering of the layer thickness. In addition, the contacting wheels have to be removed again and again to remove the undesired metal deposits, cleaned of the metal deposits and reassembled.

In view of the described disadvantages of rolling contacting of the workpieces, it has also already been proposed to use an endlessly circulating, supplying means with such galvanizing devices as contact and transport means. provide a series of individual clamping elements which hold the side edges of the plate-shaped workpieces and move them in the transport direction. At the beginning and end of the transport path through the electrolyte, means are required which cause the plate-shaped workpieces to be gripped by the clamping elements or the plate-shaped workpieces to be released by the clamping elements. With this solution, undesired metal deposits on the endlessly rotating clamping elements outside the galvanizing cell can be removed again in a separate demetallization chamber by electrolytic means.

US Pat. No. 3,729,390 discloses a galvanizing device for metal strips which are transported in a horizontal pass through an electrolyte, the feed being carried out by rollers arranged in pairs. The level of the electrolyte is adjusted so that it lies slightly above the metal strips passing through. For the cathodic contacting of the metal strips, the upper rolls are each formed as contact rolls. Above the continuous metal strips, metallic shields are arranged parallel to the contact rollers, which are at a negative potential that is slightly lower than the negative potential of the contact rollers. This measure results in metal deposits on the shields, while metal deposits on the contacting rollers are prevented.

From "PATENT ABSTRACTS OF JAPAN", vol. 13, number 423 (C-638) (3771) September 30, 1989, a similarly constructed electroplating device for metal strips is known, in which metal deposits on the contact rollers are electrolytically restored from time to time be removed. This electrolytic removal takes place via appropriately polarized electrodes, which extend in the longitudinal direction of the contact roller. zen are moved back and forth.

The invention specified in claim 1 is based on the problem of ensuring, with simple means, reliable and maintenance-friendly cathodic contacting of the workpieces passing through in a galvanizing device for plate-shaped workpieces to be treated in the horizontal pass.

The invention is based on the finding that when contact elements, such as contact wheels, which are arranged rotatably in the electrolyte, undesired metal deposits can be eliminated on the spot by arranging an associated auxiliary cathode against which the contact elements are anodically connected . The advantages achieved by the invention are, in particular, that undesired metal deposits on the contacting members can be automatically removed again during the galvanizing operation before the contacting of the workpieces is impaired and thus the layer thickness of the electrodeposited layers is scattered is coming.

Advantageous embodiments of the invention are specified in claims 2 to 42.

The embodiment according to claim 2 enables a particularly simple contacting of the workpieces which are guided through the electrolyte between lower contacting wheels and upper pressure rollers.

In the embodiment according to claim 3, the paired arrangement of lower and upper contacting wheels results in particularly efficient cathodic contacting of the workpieces passing through. In the embodiment according to claim 4, the cathode current is fed to both sides of the workpieces, so that a particularly uniform layer thickness distribution can be achieved in the galvanic metal deposition.

The development according to claim 5 with a contacting roller as the contacting element is particularly suitable for printed circuit boards in which no conductive tracks are to be produced by the galvanic metal deposition, but only through-contacts are to be produced.

In the embodiment according to claim 6, the driven contacting members also take on the task of a transport device, so that the entire electroplating device is of a particularly simple construction.

According to claim 7, a particularly efficient demetallization results if lower contacting wheels are assigned a lower auxiliary cathode. If lower and upper contacting wheels are used, then lower and upper auxiliary cathodes are assigned accordingly in accordance with claim 8.

The embodiment according to claim 9 enables the contacting elements to be demetallized in a particularly maintenance-friendly manner without simultaneous metal deposition on the associated auxiliary cathode. Removal and cleaning of the auxiliary cathode can thus be completely eliminated.

According to claim 10, πtmetallization chambers are formed by shields arranged in the electrolyte, which enable optimum demetallization of the contacting elements without impairing the galvanic metal deposition on the workpieces.

The embodiment according to claim 11 enables a Secure guidance of flexible workpieces, such auxiliary guides being particularly suitable for the inner layers of printed circuit boards.

In the embodiment according to claim 12, the horizontal arrangement of the contacting wheels considerably simplifies the sealing of the corresponding shafts and the power supply to these shafts. In addition, the formation of demetalization chambers is considerably simplified by the horizontal arrangement of the contacting wheels, shields and the like being at least largely dispensed with.

The embodiment according to claim 13 enables a further improvement in the cathodic contacting of the workpieces. In the case of the driven, horizontally aligned contacting wheels, the friction that occurs between the contacting wheels and the workpieces always ensures bare metal surfaces in the contacting area.

The embodiment according to claim 14 enables particularly secure guidance of the workpieces passing through, so that, for example, flexible workpieces, such as the inner layers of printed circuit boards, can also be treated.

In the embodiment according to claim 15, the guide wheels then form a main drive for the safe transport of the workpieces through the electrolyte.

The embodiment according to claim 16 enables a further simplification, in particular without upper contacting wheels.

In the development according to claim 17, the metal deposit on the auxiliary cathode arranged as a band can be monitored particularly easily. In the embodiment according to claim 18, a number of structural simplifications are made possible by the common lower and upper drive shafts with regard to the supply of the cathode current, the drive of the contacting members and the guidance of the workpieces.

The embodiment according to claim 19 enables a one-sided arrangement of the drive of the contacting members. In addition to reducing the drive effort by 50%, this also creates space on the opposite side. The development according to claim 20 enables the cathode current to be supplied on one side of the electroplating device, the drive and the supply of the cathode current preferably being arranged on opposite sides of the electroplating device.

The embodiment according to claim 22 enables particularly high current densities, since when a worm drive is viewed in the direction of passage of the workpieces, particularly short distances between the contacting members or between the drive shafts can be achieved.

The development according to claim 23 enables the guiding wheels arranged on the drive shafts to guide the workpieces continuously with little effort, so that, for example, flexible workpieces can also be treated like the inner layers of printed circuit boards.

The embodiment according to claim 24 ensures a safe transmission of the cathode current through the round copper rod, while the titanium sheath offers reliable protection against corrosion. According to claim 25, the electrical insulation from the electrolyte is thereby achieved in a particularly simple manner by a shrink tube made of electrically insulating material.

The advantages achieved with the configuration according to claim 26 consist, in particular, in that the contact rollers enable reliable cathodic contacting of workpieces of different widths, while the cover screen shields the anode regions which are not directly opposite the workpieces and thus a uniform layer thickness distribution of the electrodeposited Metal layers allows. Without this shielding, the protrusion of the anode on the adjacent side of the workpieces passing through would lead to higher current densities and thus to partially higher layer thicknesses of the electrodeposited metal layers.

The embodiment according to claim 27 enables effective shielding of a lower anode and an upper anode by separate cover panels.

The embodiment according to claim 28 enables a particularly simple adaptation of the cover panel to the respective width of the workpieces to be treated. According to claim 29, this adaptation can then be further simplified by a cover panel that can be moved transversely to the direction of passage.

The development according to claim 30 ensures secure guidance of workpieces of smaller width. According to claim 31, this reliable guidance of the workpieces running through can be implemented in a particularly simple manner by means of lower and upper pressure wheels arranged in pairs, the axes of which are inclined to the transverse direction.

The embodiment according to claim 32 enables with little Effort to accommodate the contacting elements in the assigned demetallization chambers, the walls of which are also used to guide cover panels at the same time.

If the contacting members are composed of at least two roller segments, as seen in the transverse direction, this enables a particularly simple and stable design of the assigned demetallization chamber. In particular, a cross bar of the assigned demetallization chamber can then be arranged between two roller segments.

The advantages achieved with the embodiment according to claim 35 consist in particular in that the covers applied to the end faces of the contacting wheels with little effort on the one hand do not adversely affect the cathodic contacting of the workpieces passing through and on the other hand reliably prevent undesired metal deposits on the end faces .

The development according to claim 36 offers reliable protection of both end faces of a contacting wheel against undesired metal deposits. This protection can then also be extended to the drive shafts of the contacting wheels by the configuration according to claim 37.

The development according to claim 38 ensures reliable lateral guidance of the continuous workpieces with little effort.

The covers of the end faces of the contacting wheels can be applied, for example, in the form of paint or by swirl sintering. The application of plate-shaped covers according to claim 39 is, however, particularly stable and permanent and can also be implemented with little effort. The development according to claim 40 offers the possibility of having additional shields applied to the end faces, since high molecular weight polyethylene in particular is distinguished by its good sliding properties.

The design according to claims 41 and 42 ensures a high level of corrosion resistance of the contacting wheels or the drive shafts of the contacting wheels.

Embodiments of the invention are shown in the drawing and are described in more detail below.

Show it:

FIG. 1 shows a partial cross section through an electroplating device for through-contacting and electroplating printed circuit boards with the basic principle of electrolytic demetallization of contacting wheels,

FIG. 2 shows a partial longitudinal section through the electroplating device according to FIG. 1 in the region of the contacting wheels and the associated auxiliary cathodes,

3 shows a galvanizing device constructed in accordance with FIGS. 1 and 2 with contacting of the continuous printed circuit boards on both sides,

FIG. 4 shows a partial cross section through a second embodiment of an electroplating device according to the invention, in which lower and upper contacting wheels arranged in pairs are used, and

Figure 5 shows a third embodiment of an electroplating device according to the invention, in which the cathodic

Workpieces are contacted via contact rollers follows.

FIG. 6 shows a partial cross section through a fourth embodiment of an electroplating device according to the invention, in which horizontally arranged lower contact wheels are used,

FIG. 7 shows a plan view of the contacting area of contacting members and continuous circuit board of the galvanizing device shown in FIG. 6,

FIG. 8 shows a cross section through a fifth embodiment of an electroplating device according to the invention,

FIG. 9 shows a longitudinal section through a sixth embodiment of an electroplating device according to the invention for through-contacting and electroplating printed circuit boards of different widths,

FIG. 10 shows a contacting roller composed of several roller segments of the galvanizing device shown in FIG. 9,

11 shows the passage of a printed circuit board of maximum width between a lower and an upper anode of the electroplating device shown in FIG. 9,

12 shows the passage of a printed circuit board of smaller width between a lower and an upper anode of the electroplating device shown in FIG. 9,

FIG. 13 shows a half-sided longitudinal section through an upper contact wheel and its drive shaft,

FIG. 14 shows in detail a longitudinal section through the circumferential area of the contacting wheel shown in FIG. 13 and 15 shows a half-sided longitudinal section through a lower contact wheel and its drive shaft.

FIG. 1 shows a cross section through the left area of a galvanizing device for printed circuit boards Lp, viewed in the direction of passage, which are transported in a horizontal position and in the horizontal direction of passage by an electrolyte which cannot be identified in more detail. This electrolyte is accommodated in a container B1, of which two side wall parts Swll and Swl2, a lower end plate Aul and an upper end plate Aol can be seen in FIG. 1, arranged in layers and connected by screws Sb. The lower end plate Aul, which is made of titanium, for example, forms a lower anode AI together with spherical anode material Am. In the exemplary embodiment shown, the anode material Am is copper balls.

For the transport and for the cathodic contacting of the printed circuit boards Lp, lower contacting members Kl designed as contacting wheels are provided, each of which is driven via a drive shaft Awl, a worm wheel Sri arranged thereon and a worm Schi extending in the direction of passage. The drive shafts Awl of the lower contacting members Kl are supported by bushings Bul and Bu2 in the side wall parts Swll and Swl2, the projecting ends of the drive shafts Awl carrying V-ring seals V. As can be seen in particular from FIG. 2, an upper pressure roller Ar is assigned to each lower contact element K1. These upper pressure rollers Ar, which are provided with an elastic O-ring 0 on their circumference, are arranged obliquely in order to ensure safe cathodic contacting and safe transport of the printed circuit boards Lp through the galvanizing device. The one against the lower contact organs The pressure acting on the pressure rollers Ar is generated by a pressure spring Df supported on the upper end plate Aol and a pressure piece Ds lying on the axis Ac of this pressure roller Ar. The axes Ac are arranged in recesses Ap of the side wall part Swl2, which allow the pressure rollers Ar to move upwards to adapt to different thicknesses of the continuous printed circuit boards Lp. Accordingly, an upper shield Aso assigned to the upper pressure rollers Ar is also guided in the vertical direction in corresponding slots Sz of the side wall part Swl2.

The circuit boards Lp are cathodically contacted via the lower contacting members K1, their drive shafts Awl and carbon brushes Kb, which are connected to the negative pole of a galvanizing current source GS1. The positive pole of this electroplating current source Gsl is connected to the lower end plate Aul of the lower anode AI.

A shield Asl made of electrically insulating material, which is arranged parallel to the side wall Sw2, forms a demetallization chamber EK1 in the region of the side wall part Swl2, in which the lower contacting elements K1 and auxiliary cathodes H1 arranged below it are located. This plate-shaped, for. B. made of stainless steel auxiliary cathodes Hl are connected to the negative pole of a demetallization current source ESI, the positive pole of which is connected to the lower contacting elements Kl via the carbon brushes Kb and the drive shafts Awl.

The lower contacting members K1 are thus connected cathodically with respect to the lower anode AI and anodically with respect to the associated auxiliary cathodes H1. Accordingly, copper is deposited on the lower contacting members K1 during the electroplating process, this undesired copper remote precipitation is removed again electrolytically in the demetallization chamber EK1 and is then deposited on the associated auxiliary cathode H1. The auxiliary cathodes H1 can then be removed from the demetalization chamber EK1 from time to time via covers D1 which are detachably attached to the side wall part S11 and the copper deposits can be removed. The decoupling of the lower contacting members K1, which is preferably carried out continuously, enables optimal cathodic contacting of the continuous printed circuit boards Lp, with no significant wear of the lower contacting members K1 being recorded.

In FIG. 1, dash-dotted lines indicate an auxiliary guide Hfl, which consists of electrically insulating material and is placed on a lower contact element K1. These auxiliary guides Hfl, which are assigned to the lower contacting members K 1, enable reliable guiding of flexible workpieces, in particular when electroplating the inner layers of printed circuit boards.

FIG. 2 shows the paired arrangement of lower contact elements K1 and upper pressure rollers Ar and the arrangement of auxiliary cathodes H1, each of which is assigned to a lower contact element K1. Insulating pieces Is arranged between the individual contacting members K1 serve as additional shields which, in addition to the shields Asl already mentioned, separate the demetallization chamber EK1 from the rest of the galvanizing area.

FIG. 3 shows a cross section corresponding to FIG. 1 through an entire electroplating device, in which the continuous printed circuit boards Lp are guided on both sides between the lower contacting members K1 and the upper pressure rollers Ar. It can be seen that separate galvanizing power sources Gsl and demetallization current sources ESI are arranged. The current sources can also be divided into several separate current sources when viewed in the direction of flow. This enables an optimal regulation of the electroplating current during the passage of the printed circuit boards Lp.

FIG. 4 shows a partial cross section through a second embodiment of an electroplating device according to the invention. In this second embodiment as well, printed circuit boards Lp are transported in a horizontal position and in the horizontal direction of passage through an electrolyte which is accommodated in a container labeled B2. The container B2 is formed by two layered side wall parts Sw21 and Sw22, a lower end plate Au2 and an upper end plate Ao2. The lower end plate Au2 together with spherical anode material Am forms a lower anode A21, while the upper end plate Ao2 carries an inert upper anode A22 via holder Ha.

Lower contacting members K21 and upper contacting members K22 designed as contacting wheels are provided for the transport and for the cathodic contacting of the printed circuit boards Lp. The paired lower and upper contacting elements K21 and K22 are both driven, the drive being provided by a worm gear Sch2 extending in the direction of travel, a worm wheel Sr21 arranged on the drive shaft Aw21 of the lower contacting element K21, and another on the drive shaft Aw22 of the above. Ren contactor K22 arranged wheel R takes place. The upper contacting members K22 are arranged obliquely and are pressed resiliently against the lower contacting members K21 in a manner not shown in FIG. 4.

The cathodic contacting of the printed circuit boards Lp takes place via the lower contacting members K21 and independently of this via the upper contact organs K22. For this purpose, the drive shafts Aw21 of the lower contacting members K21 are connected to the negative pole of a lower electroplating current source GS21 via carbon brushes (not shown in more detail), the positive pole of which is connected to the lower anode A21 via a lower current rail SSu extending in the direction of passage is. Similarly, the An¬ shafts are AW22 the upper contacting devices K22 through non-illustrated carbon brushes to the negative terminal egg ner upper plating power source GS22 angescr ^"variables, de¬ ren positive pole via a in flow dir. J erstrec¬ kende upper rail Sso , the upper connection plate Ao2 and the holder Ha is connected to the upper anode A22.

For the removal of undesired metal deposits from the lower contacting members K21, a lower demetallization chamber EK21 is formed by a lower shield As21, in which the lower contacting members K21 and associated lower auxiliary cathodes H21 are located. The upper auxiliary cathodes H21 fastened in detachable covers D21 are connected to the negative pole of a lower de-metallization current source ES21, the positive pole of which is again connected to the drive shafts Aw21 of the lower contacting members K21 via the carbon brushes (not shown).

To free the upper contacting elements K22 from undesired metal deposits, an upper shielding As22 forms an upper demetallization chamber EK22, in which the upper contacting elements K22 and the associated upper auxiliary cathodes H22 are located. The upper auxiliary cathodes H22, which are fastened in detachable covers D22, are connected to the negative pole of an upper deplating current source Es22, the positive pole of which is again connected to the connections via the carbon brushes (not shown). drive shafts Aw22 of the upper contacting members K22 are connected.

When electroplating flexible workpieces, in particular when electroplating the inner layers of printed circuit boards, auxiliary guides can be placed on the upper contacting members K22, as is indicated in FIG. 4 by an auxiliary guide Hf2.

The materials in the exemplary embodiment shown in FIG. 4 are copper-coated with titanium for the lower and upper contacting members K21 and K22 with the associated drive shafts Aw21 and Aw22 and for the lower busbar Ssu and the upper busbar Sso. The lower end plate Au2 and the upper end plate Ao2 are made of titanium, while the inert upper anode A22 is made of platinized titanium. The auxiliary cathodes H21 and H22, which can be removed from the respective demetallization chambers EK21 and EK22, are preferably made of stainless steel. Parts to be electrically insulated, such as the shields As21 and As22 and the side wall parts Sw21 and Sw22, are made of PVC, for example.

FIG. 5 shows a highly simplified schematic illustration of a third embodiment of an electroplating device according to the invention. The circuit boards Lp to be galvanized are moved here in the direction of passage Dr by an electrolyte which cannot be identified in more detail, the transport and the cahodic contacting being carried out by contacting members K3 driven in the direction of the pillar U. These contacting elements K3 are contacting rollers which consist of a copper-clad titanium tube and extend over the entire width of the continuous printed circuit boards Lp. The roller-shaped contacting members K3 dip into a demetal ization chamber EK3, which is formed by a U-shaped shield As3 and seals Ad lying on the contacting element K3. In this demetallization chamber EK3 there is a plate-shaped auxiliary cathode H3, to which the contacting element K3 is anodically connected. Undesired metal deposits on the contact member K3 are thus removed electrolytically again, a membrane M preventing the corresponding metal from precipitating on the auxiliary cathode H3. For this purpose, the membrane M is arranged between the contacting element K3 and the auxiliary cathode H3 and is designed as a so-called anion membrane, which is permeable to anions and impermeable to cations. If the contacting element K3 is effectively demetalized, the auxiliary cathode H3 can thus be completely dispensed with in this case.

Anodes A3 are arranged in the electrolyte on both sides of the demetallization chamber EK3, which anodes A3 are again formed here by spherical anode material Am.

In the case of the exemplary embodiments described above, the features essential for the demetalization of the rotating contact members according to the invention were described in detail, while other features, such as, for. B. the movement of the electrolyte were not mentioned. This electrolyte movement and other features are evident, for example, from EP-A-0 254 962 or EP-A-0 276 725.

Figure 6 ze_.gt a cross section through the device in the region of a left Durchlauf¬ seen Galvanisiereinrich¬ processing for printed circuit boards Lp, the Ntale in horizontal position and in horiz ^o the direction of passage are transported by a not further identify ER- Buren electrolyte. This electrolyte is accommodated in a container B4, of which a left side wall Sw4 made of an electrically insulating plastic, a lower end plate Au4 and an upper end plate Ao4 can be seen in FIG. The lower end plate Au4 and the upper end plate Ao4 are made of titanium, for example. On the lower end plate Au4 there is a lower anode basket Ak41, which together with the spherical anode material Am located therein forms a lower anode A41. In a corresponding manner, an upper anode basket Ak42 hangs under the upper end plate Ao4, which together with the spherical anode material Am located therein forms an upper anode A42. The anode baskets Ak41 and Ak42 are made of expanded titanium, for example, while the anode material Am in the illustrated embodiment is copper balls.

For the cathodic contacting of the printed circuit boards Lp, contacting elements K4 are provided, which are designed as horizontally aligned lower contacting wheels. The vertically aligned drive shafts Aw4 of the contacting elements K4 are mounted in the side wall Sw4 and are electrically insulated upwards and passed through the upper end plate Ao4. The drive of the drive shafts Aw4 is indicated in FIG. 2 by arrows Pf41, while the supply of the cathode current to the drive shaft Aw4 is indicated in FIG. 1 by an arrow Pf42. The contacting organs K4 can also be designed such that the thin edge region in which the printed circuit boards Lp rest resiliently presses upwards.

Lower and upper guide wheels Fr41 and Fr42 arranged in pairs across the width of the printed circuit boards Lp are provided for the transport and for the safe guidance of the printed circuit boards Lp. The lower guide wheels Fr41 are arranged at a distance from one another on a lower drive shaft Aw41, while the upper guide wheels Fr42 are arranged in the were arranged to each other on an upper drive shaft Aw42. An outer upper guide wheel Fr42 is assigned to a contacting element K4 in such a way that the circuit board Lp is pressed against this contacting element K4. The drive shafts Aw41 and Aw42, not shown in the drawing, can be driven by bevel gears or by spur gears and a worm. The drive shafts Aw41 and Aw42 and the guide wheels Fr41 and Fr42 consist either of electrically insulating material or of metal with an electrically insulating sheathing.

In the cross section shown in FIG. 6, to the left of the contacting element K4 there is a demetallization chamber EK4 which extends in the direction of passage Dr (see FIG. 7) of the printed circuit boards Lp and is closed to the outside in a liquid-tight manner by a cover D4. Within the demetallization chamber EK there is an auxiliary cathode H4, which is formed by a vertically oriented band which also extends in the direction of passage Dr. Compared to this auxiliary cathode H4, which is made of stainless steel, for example, the contacting elements K4 are connected anodically, so that unwanted copper deposits on the contacting elements K4 in the demetallization chamber EK4 are continuously removed electrolytically and are then deposited on the auxiliary cathode H4. By observing the metal deposits on the auxiliary cathode H4, the band-shaped auxiliary cathode H4 can then be moved further in the direction of travel Dr if necessary. When viewed in the direction of passage Dr, the auxiliary cathode H4 can, for example, be drawn off from a supply roll on one side and be taken up again from a corresponding roll on the other side.

The contacting elements K4 are in the direction of passage Dr hen preferably arranged on both sides of the continuous circuit boards Lp. In this case, the cross section shown in FIG. 6 can be supplemented by a right-hand part of the electroplating device, which is designed to be mirror-symmetrical.

FIG. 8 shows a cross section through an electroplating device for through-contacting and electroplating printed circuit boards Lp, which are transported in a horizontal position and in a horizontal direction of passage by an electrolyte which cannot be identified in more detail. This electrolyte is accommodated in a container B5, which is formed by a side wall Sw51 arranged on the left in the drawing, a side wall Sw52 arranged on the right, a lower end plate Au5 and an upper end plate Ao5. The side walls Sw51 and Sw52 are made of an electrically insulating plastic, such as. B. PVC, while the lower end plate Au5 and the upper end plate Ao5 consist for example of titanium. On the lower end plate Au5 is a lower anode basket Ak51, which together with the spherical anode material Am located therein forms a lower anode A51. In a corresponding manner, an upper anode basket Ak52 hangs under the upper end plate Ao5, which together with the spherical anode material Am located therein forms an upper anode A52. The anode baskets AK51 Ak52 and consist for example of titanium expanded metal, ^'while it is approximately, for example in the anode material on the illustrated execution concerns copper balls.

Lower contacting members K51 and upper contacting members K52 are provided for the cathodic contacting of the printed circuit boards Lp, which are formed by lower and upper contacting wheels arranged in pairs on both sides of the continuous printed circuit boards Lp. As can be seen in FIG. 8, lower and upper contacting elements K51 and K52 each the lateral edge area of the continuous circuit boards Lp. Opposing lower contacting elements K51 are arranged on a common lower drive shaft Aw51, which is formed by a copper round rod Kr encased with titanium Ti, the electrical insulation from the electrolyte being brought about by an outer shrink tube Ss made of PE or PTFE. Between the two lower contacting members K51 there are lower guide wheels Fr51, which are arranged at a distance from one another on the lower drive shaft Aw51 and which consist, for example, of soft PVC. The left end of the lower drive shaft Aw51 in the cross section shown is passed through the side wall Sw51, so that the supply of the cathode current to the lower drive shaft Aw51 indicated by an arrow Pf51 can take place outside the galvanizing device. On the opposite side, a worm wheel Sr5 is placed on the lower drive shaft Aw51, which is driven by a worm gear Sch5 extending in the direction of passage.

Upper contacting members K52 lying opposite one another are arranged on a common upper drive shaft Aw52, which is formed by a copper round rod Kr encased with titanium Ti, the electrical insulation from the electrolyte again being formed here by an outer shrink tube Ss PE or PTFE is accomplished. Between the two upper contacting members K52 there are upper guide wheels Fr52 arranged at a distance from one another on the upper drive shaft Aw52, which form pairs of wheels with the lower guide wheels Fr51 and, for example, again consist of soft PVC. The left end of the upper drive shaft Aw52 shown in the cross section shown is passed through the side wall Sw51, so that here too the supply of the cathode current to the upper drive shaft Aw52 indicated by an arrow Pf52 is outside the galvanizing device can take place. On the opposite side, a gear wheel Zr5 is placed on the upper drive shaft Aw52, which is driven by the worm wheel Sr5. It can be seen that this toothed wheel Zr5, the worm wheel Sr5 and the worm Sch5 are accommodated in a recess Ap5 of the right side wall Sw52.

Shields As51 and As52 made of electrically insulating material arranged parallel to the side walls Sw51 and Sw52 form, together with corresponding cutouts in the side walls, lower demetallization chambers EK51 and upper demetallization chambers EK52, in which the lower contacting members K51 and the Upper contacting organs K52 and lower auxiliary cathodes H51 or upper auxiliary cathodes H52 assigned to them. In relation to these lower and upper auxiliary cathodes H51 and H52, which are made, for example, of stainless steel, the lower and upper contacting elements K51 and K52 are anodically connected. Unwanted copper deposits on the lower or upper contacting elements K51 or K52 are thus removed electrolytically again in the lower and upper demetallization chambers EK51 and EK52. This ongoing demetallization ensures optimal cathodic contacting of the continuous printed circuit boards Lp.

FIG. 9 shows a longitudinal section through a galvanizing device for through-contacting and galvanizing printed circuit boards Lp, which are transported in a horizontal position and in a horizontal direction of passage Dr by an electrolyte which cannot be identified in more detail. This electrolyte is accommodated in a container B6, of which a lower end plate Au6 and an upper end plate Ao6 can be seen in FIG. The end plates Au6 and Ao6 consist, for example, of titanium. On The lower end plate Au6 has several lower anode baskets Ak61, which together with the spherical anode material Am contained therein form an anode A61. Correspondingly, several upper anode baskets Ak62, which can be pulled out in the transverse direction in the manner of a drawer, hang in guides Fg under the upper end plate Ao6 and, together with the spherical anode material Am located therein, form an upper anode A62. The anode baskets Ak61 and Ak62 consist, for example, of expanded titanium, while the anode material Am in the exemplary embodiment shown is copper balls.

Lower contacting elements K61 and upper contacting elements K62 are provided for the cathodic contacting of the printed circuit boards Lp, which are formed by lower and upper contacting rollers arranged in pairs. The contact tiero: jane K61 and K62 also simultaneously form a transport device for feeding the PCBs Lp in the direction of passage Dr. The drive shafts Aw61 and Aw62 of the lower contacting members K61 or contacting members K62, which are driven, for example, via bevel gears, which are not shown in detail in FIG . Double arrows Pf6 indicate that the upper contacting members K62 press resiliently against the lower contacting members K61 and this also enables adaptation to different thicknesses of the continuous printed circuit boards Lp.

The lower contacting members K61 are arranged in U-shaped demetalization chambers EK61, in which there are also lower auxiliary cathodes H61. In a corresponding manner, the upper contacting members K62 are arranged in U-shaped demetalization chambers EK62, in which there are also upper auxiliary cathodes H62. Find. Compared to the lower and upper auxiliary cathodes H61 and H62, which are made of stainless steel, for example, the lower and upper contacting elements K61 and K62 are anodically connected. Undesired copper deposits on the lower and upper contacting members K61 and K62 are thus continuously removed electrolytically in the lower and upper demetallization chambers EK61 and EK62. This continuous demetallization ensures optimal cathodic contacting of the continuous printed circuit boards Lp.

It can be seen from FIG. 9 in conjunction with FIG. 10 that the lower contact members K61, which are designed as contact rollers, are composed of a plurality of roller segments Ws 61, viewed in the transverse direction Qr. As a result, the demetallization chambers EK61 can then be stiffened by transverse webs Qs61 between two adjacent roll segments Ws61. The upper contacting members K62, which can only be seen in FIG. 9, are composed in a corresponding manner from roller segments Ws62, so that the upper demetalization chambers EK62 can be stiffened by transverse webs Qs62.

The width of the contacting elements K61 and K62 is matched to printed circuit boards Lp with a maximum width b60, the passage of which between the lower anode A61 and the upper anode A62 can be seen from FIG. If, according to FIG. 12, printed circuit boards Lp with a smaller width B61 are to be galvanized, their transport in the direction of passage Dr and their cathodic contacting between the lower and upper contacting members K61 and K62 pose no difficulties. So that these printed circuit boards Lp do not run away in the transverse direction Qr during the passage, auxiliary guides Hf6 are provided which, according to FIG. 9, are formed by lower and upper pressure wheels Ar61 and Ar62 arranged in pairs. The crosses shown in FIG. indicated axes Ac61 and Ac62 of the lower and upper pressure wheels Ar61 and Ar62 are arranged obliquely to the transverse direction Qr, ie they are not exactly perpendicular to the plane of the drawing. This adjustment of the axes Ac61 and Ac62 in the direction of passage Dr by a setting angle of, for example, 2 ° causes the pressure wheels Ar61 and Ar62 to exert a force acting outwards in the transverse direction Qr on the circuit boards Lp and dadv. h Ensure a reliable guidance of the continuous circuit boards Lp.

It can be seen from FIG. 9 in conjunction with FIG. 12 that when PCBs Lp of smaller width pass through, there is a lateral projection of the anodes A61 and A62. Without additional measures, this protrusion would lead to higher current densities in the right-hand region of the continuous printed circuit boards Lp in the illustration according to FIG. 12 and thus to greater layer thicknesses of the galvanically deposited metal layers. In order to prevent this and to ensure uniform layer thicknesses even with printed circuit boards Lp of smaller width, the lateral protrusion of the lower anode A61 is shielded by a lower cover plate Ab61, while the lateral protrusion of the upper anode A62 is shielded by an upper cover plate AB62 is shielded. The width b63 shown in FIG. 12 of the cover panels AB61 and AB62, which are made of an electrically insulating material, is matched to the width b61 of the circuit boards Lp running through here. In order to enable flexible adaptation of the cover panels AB61 and AB62 to different printed circuit board widths, these cover panels AB61 and AB62 are guided in the transverse direction Qr in outer grooves N6 of the demetallization chambers EK61 and EK6. The adjustment of the width of the cover panels AB61 and AB62, which cannot be seen from the drawing, can be accomplished, for example, by a bellows-shaped configuration or by an overlapping arrangement of several plates. FIGS. 13 to 15 show measures for preventing metal deposits on the end faces of contact wheels and on the associated drive shafts. Corresponding contacting wheels can be used, for example, in the electroplating devices shown in FIGS. 1, 4, 6 and 8.

Figure 13 shows an upper contact wheel K72, which is placed on a drive shaft Aw72 and welded to it. A cover Abd720 is applied to the end face of the upper contacting wheel K72 facing away from the drive shaft Aw72, while an annular cover Abd721 is applied to the end face on the shaft side. The shaft-side cover Abd721 is connected in one piece to a hollow cylindrical cover Abd 722 attached to the drive shaft Aw72. According to FIG. 14, the mushroom-shaped circumferential area of the upper contact wheel K72 projects beyond the rest of the wheel area, so that the covers Abd720 and Abd721 can be pressed into the corresponding cylindrical projection.

According to FIG. 13, the outer end of the drive shaft Aw72 is provided with a threaded hole GB72, into which a contact end piece KE72 is screwed. The KE72 contacting end piece can thus be easily replaced after appropriate wear.

The upper contacting wheel K72, the drive shaft Aw72 and the contacting end piece KE72 are made of corrosion-resistant titanium, while the covers Abd720, Abd721 and Abd722 consist of high-molecular polyethylene, which is characterized by its good sliding properties. The KE72 contact end piece is subjected to nitriding to reduce wear, forming a surface layer of titanium nitride (TiN). Figure 15 shows a lower contact wheel K71, which is placed on a drive shaft Aw71 and welded to it. A cover Abd710 is applied to the end face of the lower contacting wheel K71 facing away from the drive shaft Aw71, while an annular cover Abd711 is applied to the end face on the shaft side.

A hollow cylindrical cover Abd712 is applied to the drive shaft Aw71, which has a guide collar Fb71 which projects beyond the lower contact wheel K71 in the radial direction and bears against the cover Abd711 in the axial direction. The guide collars Fb71 of the lower contacting wheels K71 enable the continuous circuit boards to be guided securely.

The outer end of the drive shaft Aw71 is provided with a threaded bore Gb71, into which a contacting end piece KE71 is screwed.

The lower contacting wheel K71, the drive shaft Aw71 and the contacting end piece KE71 are made of corrosion-resistant titanium, while the covers Abd710, Abd711 and Abd712 consist of high-molecular polyethylene. The surface layer of the KE71 contact end pieces consists of titanium nitride.

Claims

1. Electroplating device for plate-shaped workpieces to be treated in the horizontal pass, in particular printed circuit boards (Lp), with at least one anode arranged in the electrolyte (AI; A21, A22; A3) and with rotatable contacting elements (Kl; K21, K22; K3) for cathodic contacting of the workpieces passing through, characterized in that the contacting elements (K1; K21, K22; K3) are anodically connected with respect to at least one auxiliary cathode (H1; H21, H22; H3) arranged in the electrolyte.

2. Electroplating device according to claim 1, that the contacting members (K1) are formed by lower contacting wheels, each of which is assigned an upper pressure roller (Ar).

3. Electroplating device according to claim 1, so that the contacting members are formed by paired lower and upper contacting wheels.

4. Electroplating device according to one of the preceding claims, that the contacting members (K1, K22, K22) are arranged on both sides of the horizontally continuous workpieces.

5. Electroplating device according to claim 1, characterized in that the contacting members (K3) by extending over the entire width of the workpieces passing through Contact rollers are formed.

6. Electroplating device according to one of the preceding claims, that at least some contacting elements (Kl; K21, K22; K3) are driven by the electrolyte for the transport of the workpieces.

7. Electroplating device according to claim 2, so that at least one lower auxiliary cathode (Hl) is assigned to the contact organs (K1) formed by lower contacting wheels.

8. Electroplating device according to claim 3, characterized in that at least one lower auxiliary cathode (H21) is associated with the contact bodies formed by lower contact wheels (K21) and that the contacting members (K22) formed by upper contact wheels (K22) are at least one upper auxiliary cathode (H22) assigned.

9. Electroplating device according to one of the preceding claims, that a membrane is arranged between a contacting member (K3) and the associated auxiliary cathode (H3), which is permeable to anions and impermeable to cations (M).

10. Galvanizing device according to one of the preceding claims, characterized in that by means of shields arranged in the electrolyte (Asl; As21, As22; As3), demetallization chambers (EKl; EK21, EK22; EK3) are formed, in each of which at least one contacting element (K1; K21, K22; K3) and at least one auxiliary cathode (H1; H21, H22; H3) are arranged.

11. Electroplating device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that auxiliary guides (Hfl, Hf2) for flexible workpieces are placed on the contacting members (Kl; K21).

12. Galvanizing device according to claim 1, so that the contacting members (K4) are formed by horizontally arranged contacting wheels.

13. Electroplating device according to claim 12, so that the contacting members (K4) are driven.

14. Electroplating device according to claim 12 or 13, so that the guide wheels (Fr41, Fr42) arranged vertically above and below the workpieces are arranged across the width of the continuous workpieces.

15. Electroplating device according to claim 14, so that the guide wheels (Fr41, Fr42) are driven by the electrolyte for the transport of the workpieces.

16. Electroplating device according to claim 14 or 15, characterized in that the contacting members (K4) are formed by horizontally arranged lower contacting wheels, each of which an upper guide wheel (Fr42) is assigned.

17. Electroplating device according to one of claims 12 to 16, so that the auxiliary cathode (H4) is formed by a vertically aligned band which extends on the outside of the contacting members (K4) in the direction of passage (Dr) of the workpieces.

18. Electroplating device according to claim 1, characterized in that the contacting members (K51, K52) are formed by pairs of lower and upper contacting wheels arranged on both sides of the continuous workpieces, with mutually associated lower contacting wheels on a common lower drive shaft (Aw51) and one ¬ other associated upper contact wheels are arranged on a common upper drive shaft (Aw52).

19. Electroplating device according to claim 18, so that the lower drive shaft (Aw51) and the upper drive shaft (A52) are only driven on one side, as seen in the direction of passage of the workpieces.

20. Galvanizing device according to claim 18 or 19, characterized in that mutually associated lower contact wheels by the common lower drive shaft (Aw51) and mutually associated upper contact wheels by the common upper drive shaft (A51) are electrically connected to each other that the lower drive shaft ( Aw51) and the upper drive shaft (Aw52) are electrically insulated from the electrolyte and that the cathode current, viewed in the direction of passage of the workpieces, is closed only on one side of the drive shafts (Aw51, Aw52). leads.

21. Electroplating device according to claims 19 and 20, so that the drive shafts (Aw51, Aw52) are driven on one side as seen in the direction of passage of the workpieces and that the cathode current is supplied on the opposite side.

22. Electroplating device according to claims 19, 20 or 21, so that the drive shafts (Aw51, Aw52) are driven by a worm extending in the direction of passage of the workpieces.

23. Electroplating device according to one of claims 18 to 22, d a d u r c h g e k e n n z e i c h n e t that on the lower drive shaft (Aw51) and the upper drive shaft (Aw52) paired associated lower and upper guide wheels (Fr51, Fr52) are arranged.

24. Electroplating device according to one of claims 20 to 23, that the drive shafts (Aw51, Aw52) are formed by a round copper rod (Kr) coated with titanium (Ti).

25. Electroplating device according to claim 24, characterized in that a shrink tube (Ss) made of electrically insulating material is applied to the drive shafts (Aw51, Aw52).

26. Electroplating device according to claim 1, characterized in that the contacting members (K61, K62) are formed by contact rollers adapted to the maximum width (b60) of the workpieces to be treated and that the passage of workpieces of smaller width (b61) leads to the side areas of the anode (A61, A62) protruding from the workpieces are shielded by at least one cover plate (AB61, AB62).

27. Electroplating device according to claim 26, so that a lower cover plate (AB61) is assigned to a lower anode (A61) and that an upper cover plate (AB62) is assigned to an upper anode (A62).

28. Electroplating device according to claim 26 or 27, so that the width (b63) of the cover panel (AB61, AB62) is adjustable.

29. Electroplating device according to one of claims 26 to 28, d a d u r c h g e k e n n z e i c h n e t that the cover panel (AB61, AB62) is arranged to be displaceable transversely to the direction of passage (Dr).

30. Electroplating device according to one of claims 26 to 29, d a d u r c h g e k e n n z e i c h n e t that at least one auxiliary guide (Hf6) is assigned to the workpieces passing through.

31. Electroplating device according to claim 30, characterized in that the auxiliary guide (Hf6) arranged in pairs lower and upper pressure wheels (Ar61, Ar62) is formed, the axes (Ac61, Ac62 of the transverse direction (Qr) are inclined.

32. Galvanizing device according to one of claims 26 to 31, characterized in that the contacting members (K61, K62) are arranged in U-shaped demetalization chambers (EK61, EK62), in the walls of which grooves (N6) for guiding cover Panels (AB61, AB62) are introduced.

33. Galvanizing device according to one of claims 26 to 32, so that the contacting members (K61, K62) in the transverse direction (Qr) are composed of at least two roller segments (Ws61, Ws62).

34. Electroplating device according to claims 32 and 33, so that a cross bar (Qs61, Qs62) of the assigned demetalization chamber (EK61, EK62) extends between two roller segments (Ws61, Ws62).

35. Galvanizing device according to one of Claims 2 to 4, so that covers (Abd710, Abd711, Abd720, Abd721) made of electrically insulating material are applied to the end faces of the contacting wheels (K71, K72) for shielding against the electrolyte.

36. Galvanizing device according to claim 35, characterized in that the covers (Abd710, Abd711, Abd720, Abd721) on both end faces of the contacting wheels (K71, K72) are upset.

37. Galvanizing device according to claim 35 or 36, d a d u r c h g e k e n n z e i c h n e t,

5 that covers (Abd712, ABd722) made of electrically insulating material are also applied to the drive shafts (Aw71, Aw72) of the contact wheels (K71, K72).

38. electroplating device according to claim 37,

10 d a d u r c h e k e n n e e c h n e t that guide collars (Fb71) are attached to the covers (Abd711) of the drive shafts (Aw71) of lower contact wheels (K71) for lateral guidance of the continuous workpieces.

15

39. Galvanizing device according to one of claims 35 to 38, d a d u r c h g e k e n n z e i c h n e t that 20 plate-shaped covers (Abd710, Abd711, Abd720, Abd721) are applied to the end faces of the contacting wheels (K71, K72).

40. electroplating device according to one of claims 35 to 39,

25 g e k e n n z e i c h n e t d u r c h

Covers (Abd710, Abd711, ABd712, Abd720, Abd721, Abd722) made of polyethylene.

41. Galvanizing device according to one of claims 35 to 30 40, g e k e n n z e i c h n e t d u r c h • Contact wheels (K71, K72) made of titanium.

42. Galvanizing device according to one of claims 35 to '41, characterized in that that the drive shafts (Aw71, Aw72 ^{) of} the contact wires ₍ K71, K72) are made of titanium.