CA2141604C

CA2141604C - Process for the electrolytic processing especially of flat items and arrangement for implementing the process

Info

Publication number: CA2141604C
Application number: CA002141604A
Authority: CA
Inventors: Reinhard Schneider; Rolf Schroder; Klaus Wolfer; Thomas Kosikowski
Original assignee: Atotech Deutschland GmbH and Co KG
Current assignee: Atotech Deutschland GmbH and Co KG
Priority date: 1992-08-01
Filing date: 1993-08-02
Publication date: 2005-05-24
Anticipated expiration: 2013-08-02
Also published as: ATE143422T1; HK38697A; SG46609A1; ES2093524T3; EP0652982A1; EP0652982B1; CA2141604A1; JPH07509539A; WO1994003655A1

Abstract

The invention relates to a process for the electrolytic processing of flat and perforated items, especially in the form of printed circuit boards with drillings, which are taken through a treatment bath or to a processing station by conveyor means, in which there are means for reducing the metal-ion-depleted diffusion region in front of the surface of the items to be processed. For this purpose, in the presence of an anode and a cathodic item (K) or a cathode and an anodic item, the surface (K1) of the item to be treated is continuously mechanically wiped and the electrolyte is moved in a component substantially perpendicular to the plane of the item to be processed and taken through its drillings (42). The description also relates to an arrangement for implementing the process which contains means (W) for wiping the surfaces of the items to be treated and means to move the electrolyte through its drillings.

Description

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FROM : TEL: JRN.25. 1995 10:08 HM P14 WU 94/03G5r~ 1'CT/L7h,93/OOG84 I'C:1'/L)1/c)3 A'1'()'I'1?C:IwI f)I~:UTSC;HI.AN1) GMI;Id, Berlin f)t I'50~20 1'C:'1' Lt:v.i:...,l~vlyti~c~ro~css~,tg of.J.'.ul>'~-~uir.
fans...~atit.lt..rD_rillings.~tud ~L1~',l'~11~11L.~LI1.~2~111't;J1t111~,.4hC! 1~1'VCPSS
'I'hc invcnticm relates, first, to a process far the clrca.rolytic proccs,ing of printed circuit boards wirh drillings, which arc. taken through a treatment bath or to a prac:essing action by cnnveyor means, in which there are ntcans for reducing the thickness of a metal-ion-depleted region (diffusion cone), which arc in contact with the printed circuit hoards.
'1'Ire preferred area of use fur the invention i;; galvanization, w)tich will be discussed in store detail below.
The invention can also he used in clecarolytic etching.
The surface of the items to be processed or their diffusion layer bcc~mcs deplet.cd of metal ions in a disadvantageous manner ~1~~60~~
FROM : TEl_: .TRN.25.1995 10:09 f~'1 P15 WC) 9~1/0:~~55 I'C:'1'/1.)L;93/OOG84 during prcu~~ssing, hacauso the c~athc~dc~ draws ntc~re inns to it then usually come: out c~f the surrounding wcatrrt~nt Lath. ''('his leads to a rc~durtion in tltc accrptahle apcoific. current:
dc:vsit:y, .tncl thus means that in order to achieve such a metal coaring havity a particular thiclcncss, a rorrcspondingly long treatment time is needed.
In order to omrcomc this disadvantage, t:hc so-called "high-sl.~ecd" process can be used, in which the clcct:rolytc is ronduetcd ac great speed and in great: quantity along the catholic surface be.t:wecrr this surfacx and the~, anode (scr; Curopean 1'atcnt 0 14z 010 and German Patent 35 25 183, lcrr example). It is true that using this prUc~ess, an improved, i.e. increased, e:urrettt density of the. mcaal coating an t)tc cat.h~dic it:csrn is achieved. Idowev~r, the production, cant.rc~1 and discharge c~f such an electrolytic current is relatively expensive, The creation of the flow channels necessary for this requires acldcd con~truccivc expenditures. In addition, the nranncr of ccmvc:ying tha items to be processed cart be complicat:cd. 1=~c~r these reasons, it has bcrottte known only for continuous items iv be hroc:essed, such as strips or wires.
!n the article "L:Iectrolyuc IIiKIt-Power C)vc~rgalvttniiation of Steel Strip through Boundary layer Control" ("I~Ic~c.trvlyt~.cclxr hloc-lihistun~;rlvt>>zi.r~krtng qxm ,S~a.hllx~nd drc~~v tttech~>t.ascvre Grcrmcchicl.~t.lxc:~n~lrssautt~,") by T~. Meuthen ttnd f). Wolfhard in the journal ~, I S t (Mcnrrloh~rf)ric'htr .3<) (1982, pp. 70-75), a process for t.hc electrolytic galvanization of steel strip is described, in which the strip surfacr. to be galvaniLed is pressed against and moved relative t:v :t notrvvovcn fabric, similarly to in the so-callc~.d tampon or hruslt galvanizinfi proccas. 'rite ~I~~.vO~
FRl7M : TEL: Jf~~1.25. 1995 10:09 HM P16 VL'O ')4/03655 PC'1'/h1:c)3/00684 coatinb 4lrcarc~lyte is rinsccl thrciugh the n~tnwcwrtt fabric onto the steel surface. 1-ligh4r current density is achieved tltrcnrgh thix procc~.ss during electrolytic r.inc: deposition, A similar principle is also, a;t.scribcd in 1?urapcan !'atent Aprlicatioti 0 210 072 for the electrolytic: casting crf small mc~ta) parts which arc coated with rtol.~lc metals, hspcrially for use as plug-type contt~ctors.
J~urlhc~.rmc~re, a prcrcc.ss for the coating ctf surfaces is known from 17.5, Pat. No. 3,706,650, in which nem-conductive, fluid-storing, porous, compressible m4ans arc pressed against the surfaces to be coated and rnoved relative thereto, whereby the saunter-electrode to the object to W . Cnatc.d is located in the interior of these rncans. The. elect.r~lytic fluid flows from the outsidr. to t.hc contact surfaces between the Porous, c:ompressihlc means and the surfaces t.o be coated. '1'lrc porotm, cc~mhressi~~lr, means also contains hard non-conductivt: particles, which somewhat roul;hen the surfaces of the metal work piece to be coated.
In the three aforementioned documents, no refercnc:e is made tc~ the flaw through drill hales required irr the manufacture of printed circuit boards, because ir1 all cases the surfaces to be ce»ted arc either flat or mrrG.ly curved.
In the German Document fcrr Pubic Inspection 14 4G 045, a procass far galvanization with sirrruhaneous clcctrolYtic cleaning of metal. surfaces and za ~1.!~~.b~l~
FROM : TEL: JRN.25.1995 10:10 RM P17 WC:~ c)4/03G55 1'C:'!'/1_)L,y3/OOG84 a clevic~ fur implcmeittinG this hr~~c~ss arc~. discle~scd. What is involved in this case is the coating of large drillings in atecl with the help of an inner electrode, tha nuter areas c~f which art: rrrUhcd on the inner areas of tlu~ drillings, A device of this type is not: suitable:, however, for the electrolytic prcwessity c~f printing circuit. I~aardc with drillings, I~rum 1.)F:-OS 3G 03 8r>6, a hr~coss and ;t device for galvanising flat items such as priotrd circ:ui~
ho.trds arc known. 'I'hc flat items :trc grasped and transported by a cathodically connected roller pair rc~cating at a rel;wivc~ly slow ratzti~oal shoed, '1'hc electrolyte is ~PPlied to the item by ;tn anodically conoecaed roller pair, the surflcc of which can absorb fluid, A sm;tll 2b '.-distance is deliberately maintained between the surface of the item and the surface of the anodic rollers. The rotational speed of the anodic rollers is relatively high, in order to attain a correspondingly fast electrolytic movement along the surface of the item. In this way, an increase in current density is achieved, compared to conventional immersion bath galvanization. Thus rotating, insoluble roller pairs as anodes are described.
The metal is supplied in soluble fashion via the electrolyte. The anodic roller pairs are not located below the level of the bath; therefore the electrolyte must continuously be applied to the galvanization location. The quantity of supplied electrolyte is limited, not least of all due to the close plastic screenings over the rollers. This also limits the possible galvanization current density. The plastic screenings are needed, however, in order to delay an undesired galvanization of the other, cathodically-connected roller pairs, which serve to transport the circuit boards.
Because the rotating anodic roller pairs do not touch the upper sides of the circuit boards, the diffusion layer located on the surface is not mechanically disturbed. However, the space between the anodic roller and the upper side of the circuit boards and thus the space between the pairs themselves is needed, to allow the galvanizing currents for the two sides of the circuit boards to be individually set. During galvanization of the conductor path image, this is always necessary, because the two sides of the circuit board, in practice, have uneven copper areas.
For this reason, the anodes of the upper side of the circuit board are fed from one bath current rectifier and the anodes of the bottom side are fed from a VUO 94/03655 ~ ~ ~ ~ ~ ~ ~ PCT/DE93/00684 different rectifier. Each rectifier can be individually set in respect to current.
Another disadvantage of the aforementioned invention is the very poor flow through fine holes in the printed circuit boards. On board sides located opposite to one another, electrolyte is applied in a small quantity in an almost pressure-free manner.
This prevents the flow from going through the holes, resulting in inadequate galvanization of the hole walls even to the point of burns in the holes.
The invention is based on the problem of designing a generic process so as to achieve the desired reduction in thickness of the ion-depleted border layer on the anode surface or cathode surface (diffusion layer), and to thus attain a correspondingly increased current density of the galvanization current flowing from the electrolyte onto the anodic or cathodic item, while avoiding, however, the constructive and process-related expenses of the so-called "high-speed"
flow technique.
This problem is solved and this object attained, first, starting from the generic prior art, in that in the presence of an anode and cathodic items to be processed, or in the presence of anodic items to be processed and a cathode, the surface to be treated of the items is wiped continuously by machine and the electrolyte is conveyed by a component vertical to the plane of the items and is passed through the drillings or drill holes (referred to hereinafter for the sake of simplicity as "drill holes") of the items.

CVO 94/03655 ~ 1 L~ ~ ~ ~ ~- PCT/DE93/00684 This wiping of the area or areas in question serves, in a simple, advantageous and industrially implementable manner, to counteract the disadvantageous depletion of metal ions in the diffusion layer. The diffusion layer is largely destroyed, and thus the ion-depleted zone on the surface or surfaces in question is completely or at least largely eliminated.
The metal ions of the electrolyte can therefore make their way directly onto the surface of the items in question, or, during etching, can be removed therefrom. In respect to further advantages, reference is made to the discussions below of the various possible designs of the invention, in respect to both process and object. By means of the combination according to the invention of the aforementioned wiping and the metallization of the surface which this achieves with the metallization of the inner walls of the drill holes based on conveying the electrolyte through the drill holes, an adequate treatment of the inner wall of the drill holes is simultaneously achieved, and thus the metallization of the treatment items is achieved on all required areas (surfaces and drill holes) with satisfactory results in one work step and using relatively simple measures. In this connection, the aforementioned combination has the advantage that the wiping sequence destroys any surface tension existing on the fluid in the drill holes, making it even easier to metallize the drill hole inner wall. As the examples of this invention show, the structural means for wiping, on the one hand, and for conducting the electrolyte through the drill holes (so-called "flooding"), on the other, ..-can be provided together in a simple and space-saving manner, and in the preferred design of ' the invention are even combined. Here reference is made, for example, to the design according to Fig. 15. A further advantage is that with the aforementioned flooding--particularly when this is still done by supporting a pressing of the electrolyte, e.g., by means of a pump, into the drill holes and/or a drawing of the electrolyte out of the drill holes by means of a suction device-any particles that might still be present in the drill holes can be extracted from the drill holes and transported away. This avoids the danger of particles trapped in the drill holes becoming embedded through metallization and of the drill hole in question becoming clogged, which leads to rejection of that particular circuit board.
Furthermore, in this connection, the danger is avoided of abrasive or chip particles still adhering to the edge of the drill holes being grasped by the wiping coatings and transported along the surface of the items to be processed, which can damage and even render unusable the delicate surface of the items to be processed.
A complementary attainment of the object is represented by a process in which an appropriate relative movement between the cathodic or anodic items to be processed on the one hand and an anode-side or cathode-side wiping device on the other hand achieves the effect according to the invention.
In achieving this relative movement, the transport movement of the items to be processed may be used WO 94/03655 2 ~ ~ ~ ~ ~ ~ PCT/DE93/00684 .i .3 :.~
as an alternative when the items are taken by conveyor means through a treatment bath.
The further subclaims present preferred designs of the invention:
The possible process measures provided according to the invention for the attainment of the object may preferably be used for galvanization, but may also be used for electrolytic etching.
The items (work pieces) to be processed thereby has an anodic function, i.e., it is anodically connected. The etched-away metal is precipitated on a counter-electrode (cathode). The counter-electrode can be the wiping device. Then, in a later work step, the precipitated metal is carried away and re-obtained. Electrolytic etching of this type is an alternative to purely chemical etching. During electrolytic etching, a simultaneous wiping of the anodes disrupts a border layer appearing there.
In order to simplify the presentation of the invention, the invention will be discussed below, and in the description of the examples related to the drawings, in reference to processes and devices for galvanization.
The movement of the coated anode relative to the item to be galvanized, whereby the coating bears against the item, largely destroys the diffusion layer (see above) and thus completely or largely eliminates the metal-ion-depleted region on the surface of the items to be processed.

~~c70 94103655 ~' ~ ~ ~ ~ ~ ~ I'CT/DE93/00684 The ions of the electrolyte can make their way directly through the coating of the anode to the surface of the item to be processed and metallize it. 1n this way, relatively high current densities can be achieved, and with good quality, particularly with an even strength of metal layer precipitated on the item surface, e.g., a copper layer. This is a significant advantage, which is especially important when it is not the entire area that is to be coated, but only the surface of conductor paths located on a circuit board of this type. A further significant advantage of the invention is that the distance between the anode and the cathodic item is still determined only by the thickness of the coating on the wiping device, whereby this thickness, however, can be relatively small. Due to the very small distance thus achieved between the anode and the cathode, different field line concentrations of the galvanization current flowing from the anode to the cathode practically do not exist, or at least exist to a considerably lesser extent than in arrangements in which a comparatively large distance exists between the anode and the cathode. In previously known arrangements with a relatively large distance between the anode and cathode, it was necessary, in order to avoid damaging effects such as increased metal precipitations on edge regions, e.g., the so-called "dog-bone" effect, to make appropriate expenditures, e.g., to provide "blendings." This is especially true in the case of flat items to be processed, such as electronic printed circuit boards, which have a great many drillings.
Here, considerable scatterings (known as drill hole scatterings) can result on the edge region of the boards and in the drill holes.

r--WO 94/03655 ~ ~ ~ ~ ~ ~ ~ PCT/DE93/00684 A significant advantage of the invention is that it achieves higher current density values, without the depletion of metal ions causing so-called "burns" or the like of the metal to be deposited. Blendings or similar measures against excessive scatterings of the galvanizing current are not needed. A further significant advantage of the invention is that it is suitable for the automatic galvanization of items running continuously through a unit (perforated boards or the like). This will preferably occur in the case of items arranged and transported horizontally (see, for example; DE-OS 36 24 481, discussed below). However, the invention can be used not only with horizontal, but also with vertical or slanted runs, and such usage will be accompanied by the advantages discussed above, particularly the avoidance of damaging scatterings at high current densities. When it is possible for higher current densities to be applied, as they can be as a result of this invention, the transport speed also becomes faster or the treatment route shorter. In particular, it is not necessary to ensure a disturbingly high flow rate of the electrolyte.
With the invention, a wiping effect is automatically achieved on the entire surface to be treated, in particular, on both sides or surfaces of flat items. For the sake of completeness, it should be mentioned that in manual galvanization, the process referred to as tampon galvanizing is known, used particularly for the processing, repair or improvement of larger components which cannot ~~ 1~~'~

be processed or can be processed only with great difficulty in a galvanizing unit. Typical examples of this are the improvement or galvanization of metal church roofs, large monuments and the like. For details, reference is made to the publications of RUBINSTEIN
in the journal Galvanotechnik ("Galvano-Technology") No. 73 (1982), pp. 120 ff; No. 79 (1988) pp. 2876 ff and pp. 3263 ff. Such a tampon process, however, can be used only for the aforementioned special cases, not for the industrial production of printed circuit boards with drillings and the like.
In a preferred design form of the invention, not only the transport speed of the processed items, but also the speed of the coated anodic device itself is used to achieve an intensive wiping effect. Depending on requirements and design, a great variety of effects and wiping speeds can be achieved.
The aforementioned relative speed may be low, e.g., almost approaching zero.
Furthermore, in implementing the process according to the invention, pressure can be exercised by the wiping device on the items to be processed. In the presence of an elastic coating on the wiping device, the coating can be flattened or pressed. Apart from the fact that irregularities in the thickness of the items can be smoothed out in this way, this helps to reinforce the effect according to the invention of disrupting the diffusion layer. This is especially true for the disclosed combination of features.

FROM : TEL: JRN.25. 1995 10:10 RM P18 WC) ')~I/03G55 1'~~ 1'/D1:H3/t)OGBA
further proc-c~cs Inc:asuras prcrntotc thc~ Massage of the elcct.nc~lytc through the drill holes and t.lrus the metaliii.at:ic~n of the innrr walls of the drill holes.
1~urtherrnorr., they contribute t.o cxtractinK from t.hc drill lmles particles or the like pr4sent therein.
The. invention is also based on the; object c~f crcat.ing an arrangement for the electrolytic prcreessing c~f printed circuit boards with drillings, which al-c taken by conveyer means throu6h a treat.mc.nt 1>ath, or conducted tc~ a t.reatntent station, whcrcsby means fc~r rcauciog the thi~knc.ss ~f a metal-ion-depleted r.ono {dlffuslon layer) are provided, which arc in contact with the printed circuit hoards, which arrangement achieves flawless electrolytic processing, rossiL~lc: with simr~le means, of one or hot:h surfaces of the printed circuit boards as well as of the: drillings or drill hc~lcs {hereinafter called "drill holes") located therein. 'l'his is possible in particular with the Proctors rneasures according to one or more o!' the process claims of the Present. invcntian.
'!'o attain these cibjects and solve these problems, first of a11, the arranpament has rnsans for wiping the surface or surfaces of either catholic items or anodic iterns, and also has nteans for conducting ehc electrolyte, in a flow roughly vercica) to the plane: of the items to be: processed, through the drill holes of the lat.tcr (flooding mcans~, 'This principle of the invention is to be ro:tlized in a structurally simple form, as ,"...
WO 94/03655 ~ ~ ~ ~ ~ ~ ~ 1'CT/DE93/00684 will be seen in greater detail in the discussion which follows, particularly the discussion of the examples.
Wiping devices with the coating are an especially advantageous design form of the invention for mechanical wiping.
It is recommended that the coating be allowed to bear against the surface of the items to be processed with a certain pressure force. This is especially advantageous in processing conductor paths and drill holes, because the fluid in the drill holes has on its surfaces a certain surface tension that is disturbed by this wiping, thus clearing the way for ions, in order to form a metal layer (during galvanization) on the surfaces. Such a pressure force can, for example, be achieved through spring bearings of the wiping device, especially the aforementioned rollers.
Flat items are especially suitable for being conveyed between rollers. Rollers per se are known in their structure and their use in units for processing flat objects;
however, they are known not in this form of wiping rollers according to the principle of the invention, but only as conveyor and guide rollers and as squeeze rolls for sealing. The rollers have the advantage of their simple and robust structure and insertion into a processing unit. In contrast to known conveyor rollers or pressure rollers, however, these wiping rollers with their coatings have the function of achieving the discussed mechanical wiping effect, i.e., their rotational speed deviates deliberately from the transport speed of the items to be processed which bear against them.
At the same time, these rollers can also be designed as a counter-electrode to the object to be processed.
The aforementioned deviation in speed can be achieved by means of the respective values of the aforementioned speeds and/or their respective directions. At this point, it should also be noted that the aforementioned speed deviation and/or relative speed may be low, almost zero.
Furthermore, the wiping rollers with their coating can mechanically favor the carrying away of particles. This is especially true when the rollers are pressed with a certain pressure force onto the surface of the items to be processed. In this way, disruptive layers on the cathode, such as gas bubbles suspended on the surface, can also be removed.
Further preferred design forms for reinforcing the metallization of the inner wall of drill holes consist of means and devices for conveying the electrolyte through the drill holes (flooding}
with appropriate overpressure or underpressure.
In another aspect, the present invention provides a process for electrolytically processing a flat perforated item, comprising the steps of moving the item in a transport direction to a treatment station where the item is contacted with an electrolyte;
continuously mechanically wiping, in the presence of one of a cathodic item and an anode, and an anodic item and a cathode, a surface of the item using means for reducing the thickness of a diffusion layer depleted in metal ions adjacent the surface of the item, which means include a wiping roller extending perpendicular to the transport direction over the entire width of the item and in contact with the item; and moving the electrolyte in a direction substantially perpendicular to a plane of the item as the item emerges from the wiping roller so as to direct the electrolyte only toward the perforations in the item to convey the electrolyte through the perforations in the item under pressure.

In another aspect, the present invention provides an arrangement for electrolytically processing a flat item having through holes and a width, comprising:
treatment means for applying electrolyte to the item;
means for transporting the item through the treatment means in a transport direction along a planar transport path;
means for contacting and reducing the thickness of a diffusion layer depleted in metal ions adj acent the surface of the item, the reducing means including a wiping roller arranged perpendicular to the transport direction, and configured so as to wipe at least one surface of the item across the entire width; and means for conveying the electrolyte only toward the holes in the item under pressure in a flow substantially perpendicular to the planar transport path as the item emerges from the wiping roller so as to force the electrolyte through the holes.
Further advantages and features of the invention are found in the other subclaims, as well as in the description which follows and in the accompanying drawings of possible designs according to the invention. The essentially schematic drawings show:
Fig. 1 A depiction, partially in section, of the process according to the invention in principle;
Fig. 2 A design for implementing the process or processes according to the invention, in front view and partially in section;
Fig 3 The side view associated with Fig. 2;
Fig. 4 A top view of the conveyor device in Figs. 2 and 3;Compared to Figs. 2 to 4, the following figures are drawn in larger scale.
Fig. 5. The conveyor device according to Line V-V in Fig. 4, in section:
Fig. 6 The Detail VI circled in Fig. 2, in enlarged scale and partially in section;
Fig; 7 A first example . . ..~r.. ~..~,~~~~..;_~n. , N~. ..~m., ..nn. o . , ..._ . ...._ w.. .
..,..x_ , . _. ~ ..M

~14~ fi0~~

of the embodiment and arrangement of the wiping rollers;
Fig. 8 A second example of the embodiment and arrangement of the wiping rollers and the flooding;
Fig. 9 A third example of the embodiment and arrangement of the wiping rollers, also showing the supply and extraction of electrolytic fluid and the flooding;
Fig. 10 A fourth example of the design and embodiment of wiping rollers, as well and the supply and extraction of electrolytic fluid and the flooding;
Fig. 11 A fifth example of the embodiment and arrangement of wiping and carrying rollers and the supply of electrolytic fluid, as well as the flooding;
Figs. 12, 13 A sixth and seventh example of the invention with wiping and flooding means;
Fig. 14 An eighth example of the embodiment and arrangement of wiping and carrying rollers and the supply of electrolytic fluid, as well as the flooding;
Fig. 15 A ninth example of the invention showing the design of the wiping rollers and an associated conduction of the electrolyte, as well as the flooding;
Fig. 16 A further (tenth) example of the invention for achiev ing the flooding and wiping effect;
Fig. 17 A further (eleventh) example of the invention for achieving the flooding and wiping effect.
The diagram in Fig. 1 shows the principle of the invention. In schematic fashion, Fig. 1 shows the principle of the invention in the case of a cathodic item K with the area Kl to be treated and the wiping device W associated with this. This wiping device W has the anodic function. The aforementioned wiping device may be wiping rollers according to the examples below or may be another wiping device. In any case, the wiping process is carried out mechanically. This process may be carned out on an item conveyed through a series of treatment baths, i.e., essentially continuously, but it may also be carried out on an item which is introduced into one of the treatment stations or into a treatment bath and processed there.
In the latter case, the wiping operation and the flooding operation explained below are discontinuous. In the case of a flat item, either one of its two surface or both of its surface can be wiped. At the same time, the electrolyte is conducted through the drill holes ("flooding").
The examples discussed below will make refer to details of the above sequence.
Figures 2 to 6 show the aforementioned main possibility for use of the invention, namely, a bath station of a galvanization unit that is designed according to the invention, including the conveyor means for the items to be processed. A series of such bath stations can be provided one behind the other, in order to allow processes to be carried out with various baths.

_ , __:

~. '~ ~. ~~ ~ '~ PCT/DE93/00684 \~O 94/03655 The bath container 1 contains a bath liquid, not shown. An item to be processed which is introduced in the direction of the arrow 2 is conducted between guide rollers, conveyor rollers and the wiping rollers, which will be discussed in more detail below. The item can be transported and processed horizontally according to this example of the invention. After processing, the item emerges from the unit in the arrow direction 3. In the areas 4 and 5, only conveyor and/or guide rollers are present and shown, whereas in area 6, in addition to any conveyor and/or guide rollers, there are also wiping rollers according to the invention. The wiping rollers are explained in detail in reference to several examples in Figs. 6 to 12, whereby Section 6 in Fig. 3 corresponds to the examples in Figs. 7, 8 and 9.
The movement path for the items to be treated has the position and breadth designated in Fig.
2 as "a." In Fig. 2, the movement direction 2-3 runs vertical to the plane of projection. In this example, a conveyor device 7 is located next to the movement path of the items to be treated, which uses conveyor means in the form of a clamp 9 to grasp in clamping fashion a flat item 8 on a lateral edge 8' and move the item 8 in the movement direction 2-3. Such a conveyor device is the subject of DE-OS 36 23 481, to the disclosed contents of which reference is hereby made. However, the invention is not limited to the use of a conveyor device designed in this manner. This lateral grasp of the flat item by the clamps 9 has a special advantage, especially in conjunction with the discussed "flooding," i.e., pressing or drawing electrolyte through the drill holes of the item. During flooding, a corresponding pressure on the item arises in the flooding direction. The clamps with their firm lateral grasp on the item prevent the board in question from being pushed by the flooding pressure. The aforementioned rill holes and the means for flooding are not shown in Figs 2 to 6, for the sake of simplicity.
Reference is again made to the examples which follow. A clamp 9, consisting of two clips 11, forms a conveyer means 10. All conveyor means are attached to a continuously rotating conveyer belt 12, 12', which rotates in the direction of the arrow 13 (see Fig. 4). When the conveyor means 10 are located on the side of the strand 12' (see Fig. 3) of conveyor belt, then the clamps 9 are in the holding position (see the drawing of the left side of the conveyor device 7 in Fig. 2). As soon as the conveyor means 10 move out of the area of the strand 12' into the upper strand 12 in Fig. 4, the two clips 11 of the clamps 9 are pulled somewhat apart, so that a space exists between them (see the right side of the conveyor device 7 in Fig. 2).
This conveyor device moves the items at a particular and if necessary adjustable speed in the direction 2-3.
Fig. 5 shows the conveyor device in detail. Fig. 5 illustrates a cross-section of the conveyor device along Line V-V of Fig. 4. It can be seen that in the area of the strand 12, through the ascent of one of the clips 11 of a clamp onto a guide part 29, the associated clamps 9 are moved into the open position. In contrast, in the path area of the strand 12', such a guide part 29 is not present, and the clips of the clamps 9 lie, under the influence of a pressure spring, with corresponding clamping force at the edge 8' of the item (transport position).
Detail VI in Fig. 2, as well as Fig 6, which depicts this detail, partially in section, show two wiping rollers 15, which are moved in opposite directions by a drive via a toothed gear 16, 17.
For this purpose, there are two spur wheels 17, which sit on the axles 13, 14 of the wiping rollers 15 and mesh with one another. The anodic wiping rollers 15 are ''1~ ~ '-~
CVO 94/03655 ~~ x ~ ~ ~ 1'CT/DE93/00684 connected via contact disks 20 and current contacts 19 which slide thereon as well as by leads 18 to the positive pole of the current source. The cathodic item 8, shown here only partially, is connected to the negative pole of the current source (not shown). Each of the wiping rollers is, on its outer circumference, provided with a coating 31 of a material which absorbs and is permeated by the electrolyte and the metal ions of the electrolyte.
This material should be elastic and have a certain softness, in order not to damage the surface of the items during the course of sliding along. The coating must be chemically resistive against the electrolyte.
The material preferably used for this is a felt-type plastic, e.g., of polypropylene. Here the term "felt-type" refers not to the textile felt, but to a structure of interwoven components.
Such materials are also known for use in filters. The coating may also consist of an open-pore plastic which has good liquid permeability and is friction-proof. This wiping coating should-as should wiping coatings of other materials--be elastic, so that during application to the surface to be wiped it compresses somewhat and then can return to its original form. The aforementioned permeability to fluids is at least necessary when, according to one of the following examples, the electrolyte is pressed from the roller interior through the coating to the outside, or is drawn in in the opposite direction.
While any drive rollers and/or guide rollers (see Number 3 and 4) which might be present have a rotational speed which corresponds in value and direction to the transport direction 2-3 and the transport speed of the conveyor means 10, the rotational speed and/or running direction of the wiping rollers is such that the circumference of the wiping rollers 15 moves relative to the respective surface of the transported items 8. In this way, a wiping effect is exercised on the surfaces of the items 8 along the entire length of the wiping rollers 15.

The length of the wiping rollers I S extends across the breadth of the items to be processed, which runs at a right angle to the transport direction, i.e., approximately the amount "a" in Fig. 2. However, an item of lesser breadth can also be processed, whereby a partial length of the wiping device 15 simply goes unused. The level of the electrolytic bath is indicated with a broken line by reference number 25, whereby the item to be processed as well as the wiping devices are located below the level in the bath fluid. This also holds true for the other examples. As the present example shows, it is advisable, or is as a rule necessary, to process an item according to the invention on both of its sides or surfaces, i.e., on the upper surface in Figs. 2, 3 and 6 as well as on the lower surface, as reflected by the arrangement of two wiping rollers 15, which bear against the respective surfaces of an item from above and from below. In cases in which only one of the surfaces of an item needs to be processed, then the use of one wiping roller suffices in principle. The fact that more than two wiping rollers can be used is illustrated by the examples in Figs. 7 to 15.
As a rule, a certain pressure force is recommended between the coatings 31 of the wiping rollers and the surfaces of the items to be processed, which pressure force, for example, can be applied by a spring 23 pressing in arrow direction 22 and indicated schematically in Fig. 6.
In order to be able to process items of varying thickness, the upper roller of the wiping rollers 15 is mounted in a slot guide 24 and can therefore, when there is an increase in the thickness of the items to be processed, give way opposite to the arrow direction 22. The bath level 25 of the electrolyte is higher than the lower edge of the slot. Excess electrolyte can therefore run out through the slot guide 24 and a space 26 between the side wall of the bath container 1 and another externally located wall 27 according to arrow direction 28.

WO 94/03655 ~ ~. ~ ~ ~J ~ ~ PCT/DE93/00684 The rotational speed and/or rotational direction of the anodic wiping rollers 15 at their contact points with items having a certain transport speed may be altered and adjusted to the desired value through a control of the drive unit of the wiping rollers. It is also possible to adjust the pressure force of the spring 23 or other pressure means. In this way, particular requirements can be matched with the goal of achieving the most extensive possible disruption of the diffusion layer on the surface of the items in which ion depletion usually occurs.
In the description which follows of examples according to the invention in the design and arrangement of wiping rollers 15 or wiping parts which act accordingly, only these components of the invention, including supply and extraction conduits for the electrolyte, are depicted and explained. Of course, this includes conveyor means for the items and drive means for the wiping parts as well as current feeds, which are depicted in Figs. 2 to 6, for example, and discussed above. In addition to the conveyor means described there, or instead of these conveyor means, it is also possible, for example, to provide conveyor rollers between every pair of wiping rollers, whereby the cathodic current feed occurs by means of loop contacts on an edge area of the items to be processed. If not already depicted in the drawing, the items to be processed has drill holes, and means are provided for "flooding" these drill holes, i.e., for passing the electrolyte through them.
Basically, the parts located in the electrolytic bath, such as the tube 30 and the expanded metal piece or wire screen 32 described below, must consist of a material which is not attacked in the bath under the electrolytic conditions. Suitable materials include, for example, titanium, titanium coated with platinum, noble metal, noble metal coating or WO 94/03655 ~ ~ ~ ~ ~ ~ ~~ PCT/DE93/00684 noble metal oxides. This can be done, e.g, according to the example in Fig. 7, in such a way that wiping rollers in the form of metal tubes 30 are provided with the aforementioned felt-type coating 31 and an expanded metal piece 32 located therebetween, which positively connects the tube 30 and the coating 31. Instead of the preferred tubular expanded metal piece mentioned above, a preferred tubular wire screen that is welded at the wire crossing points can also be used or a perforated tube can be provided. In this example, the tube 30 constitutes an insoluble anode, which does not give off metal itself, but rather has emits only current. In this case, the metal to be deposited is located in the electrolyte. However, it is also possible to store the metal to be deposited as a soluble anode in the tube 30 or in another wiping element. When the items 8 are run through, the coatings 31 are somewhat compressed. The electrolyte is supplied according to the arrows 33. This can also be done under pressure.
Here, too, the electrolyte passes through the drill holes (not shown) of the board to be processed. As will be mentioned later (at the end of the description), any feature or detail depicted in one of the examples may also be used in the other examples. This applies especially to the means for implementing the flooding of the drill holes 42 of the items to be processed. This example and the others show that the distance between the anode (here the titanium tube 31) and the cathode (identical to item 8) is very small, so that practically no scatterings occur.
The example in Fig. 8 resembles that in Fig. 7. However, Fig. 8 shows one of the possible designs for allowing the electrolyte to flow through drill holes 42 of the items to be processed.
For this purpose, the tubes 30 are provided with perforations, which have several functions.
First of all, the electrolyte in supplied in the tube interior 35 and passed along through the perforations 34 to the coating 31. Furthermore, the electrolyte is conducted from the interior of the tube 30 through the perforations 34 of the tube WO 94/03655 ~ ~ ~ ~ 6 ~ ~ PCT/DE93/00684 and the wiping coating to the drill holes 42 of the board 8; the electrolyte then flows through the latter and reaches the interior of the counter-roller in question, the tube 30 of which is likewise provided with perforations 34. The electrolyte in one tube can thereby be under pressure from a pump and the electrolyte in the counter-roller located on the other side of the items to be processed can be drawn out of the drill holes. In addition, the perforations 34 can also serve to ensure that the material of the coating 31 clings within them.
In this preferred design, only the inner tube 30 and the outer coating 31 are provided. Instead of the tube 30 with the perforations 34, a tubular expanded metal piece or wire screen can also be used.
Of course, the wiping coating 31 surrounds the wiping roller 15 in question on its entire circumference. This is true for all examples that show wiping rollers. The wiping rollers are generally indicated by the reference number 15 and an associated arrow, regardless of their somewhat different embodiments.
In the example shown in Figs. 9 to 14, the structure of the wiping rollers is the same as in Fig.
7, [consisting] namely of an inner tube 30, an expanded metal piece or the like (see above) 32 and the coating 31 which surrounds the wiping roller and thus the tube 30 as well.
In the example shown in Fig. 9, the electrolyte is supplied by means of supply tubes 37 having perforations or slits 36, which are located above the free space 38 between two wiping rollers 15. After the electrolyte runs through the intermediate spaces 38, the drill holes 42 and the intermediate spaces (39) located thereunder, it is collected by collection containers 40 and conducted to a filter pump.
When an upper wiping roller and a lower wiping roller located opposite to one another are provided (for example, in the design according to Fig. 9, then, in alternating fashion, the upper wiping roller can be connected anodically and the wiping roller located under it can be connected as the cathode, and vice versa. Such a process and an associated arrangement are depicted and described in DE 41 06 333 C1.
The example in Fig. 10 also shows wiping rollers 15 in the design according to Fig. 7 during the processing of flat items 8, especially printed circuit boards, which are provided with drill holes 42. The electrolyte is conveyed with pressure through the slit 41 of a flow nozzle 63 upward (arrow 43) through the drill holes 42 located thereover and from here conveyed back by means of underpressure through the drill holes 42 (arrow 44) located near the flow nozzle 63. As this happens, a certain pool 45 of electrolyte (with the electrolytic surface 45') builds up above the items 8 to be processed, and this pool provides electrolyte to the coatings of the two wiping rollers located about the items 8, while the wiping rollers below the items 8 are moistened through the electrolytic flows 44 as well as through the electrolyte flowing across the edge of the flow nozzle top. The latter electrolyte achieves a high speed in the narrow gap between the items 8 and the flow nozzle, as the result of which lower pressure is created than exists in the electrolyte above the flat items. This difference in pressure causes the electrolyte to be drawn through the drill holes 42. Such an flow nozzle arrangement can be provided, alone or in combination with other means which facilitate "flooding" (see the other examples in this regard), in order to convey the electrolyte through the drill holes 42.
This means which can be used for the purpose of flooding according to the invention can also eliminate diffusion poor layers in the drill holes 42, so that sufficient metal precipitation takes place on the inner wall of the drill holes. In addition, the wiping effect of the coatings of the wiping roller \~~O 94/03655 PCT/DE93/00684 on the upper and bottom sides of the items, disturbs the surface tension of the fluid columns located in the drill holes 42, thus supporting the desired effect. As mentioned earlier, the process measures and the means for wiping the surfaces of the flat items to be processed and for flooding the drill holes 42 of the flat items therefore work together functionally and synergistically.
The example in Fig. 11 is a variant of the example in Fig. 10. Here the left roller pair has an upper wiping roller 15 and a lower pressure roller 64, and the roller pair shown on the right has an upper pressure roller 64 and a lower wiping roller 15. The pressure rollers can function as conveyor rollers or support rollers, which accordingly bear with pressure against the items to be processed. Each of the anodic wiping rollers 15 wipes, in the sense of the invention, the surface of the item 8 which faces it and also wipes, at the same time, the end of the drill holes 42 which faces it. Furthermore, a flow nozzle 63 is also provided here, as in Fig. 10. A
sequential galvanization of the drill holes 42 from alternating sides in the transport direction 2-3 is achieved. The aforementioned conveyor rollers 64, at least on the upper side of the item, are designed as rollers which extend across the entire breadth of the items or the treatment path, so that the electrolyte becomes blocked up on the items 8, while the conveyor rollers on the bottom side of the item may also consist of several disks arranged on one axis, between which the electrolyte can flow.
Figures 12 and 13 show further possibilities for the use of a flow nozzle 63.
According to Fig.
12, two pairs of wiping rollers 15 are provided in front of or behind an arrangement which has the flow nozzle 63 with the anode 48 arranged therein. The electrolyte flow enters in direction 79 through a connection piece 65, passes through a pre-chamber 68 and a distribution mask 69 with perforations 66, flows (reference number 67) ~t10 94/03655 PCT/DE93/00684 along the anodes 48 consisting of individual pieces, passes through the slot 41 and the nozzle area 70 as well as through the drill holes 42 of the items 8 downward (arrow 71) into the area below the items 8. In detail, reference is made here to the disclosed contents of DE-OS 39 16 693.7. These examples also involve flat and perforated items to be processed, preferably printed circuit boards.
Fig. 13 shows a design similar to the arrangement according to Fig. 12, and the same reference numbers are used. The difference is that in the object in Fig. 12 the electrolyte, after passing through the drill holes 42, flows freely downward, while in the object in Fig.
13, a suction segment 72 with the housing 75 is provided between this outflow 71 and the exit of the electrolyte from the drill holes 42. An underpressure is produced in this via the suction connection piece 73, so that the electrolyte, after passing a further anode 48, is drawn into the space 74 under low pressure and then is extracted from there through the connection piece 73.
In connection with the object in Fig 13, reference is made to the disclosed contents of DE-OS
39 16 694.5.
In the examples in Figs. 10 to 13, the flow nozzle 63 extends across the entire breadth of the treatment items, i.e., the breadth "a" in the example from Fig. 2. The same applies for the space 68 (Fig. 12 and 13), in which the electrolytic fluid enters via a series of connection pieces 65 arranged one behind the other at a right angle to the items. In the example in Fig. 13, the suction segment 72 of the suction side extends likewise across the entire breadth "a." In these examples with the flow nozzle 63, it is thus ensured that, according to the invention, in addition to the surface treatment of the items 8 through the wiping roller 15, there occurs an intensive flowing through of the item drill holes 42 by the electrolyte, which in fact flows the entire breadth "a" of the work pieces conveyed in direction 2-3. This type of intensive electrolyte flow through the item drill holes 42 WO 94/03655 ~ ~ ~ ~ ~ ~ ~ PCT/DE93/00684 and the correspondingly heavier deposit of metallization on the inner walls of these drill holes, in combination with the previously described galvanization of the surfaces of the items due to the wiping effect, would not be possible in the arrangement according to the prior art, in which the electrolytic flow is conducted at great speed parallel to and along the work piece surface. In this case, it would not be verifiable in terms of flow engineering that the electrolytic flow passed through the drill holes at a right angle to the flow direction.
The example in Fig. 14 contains a combination of the arrangement of wiping rollers and pressure rollers according to the example in Fig. 11, with a conduction of the electrolyte as in the example in Fig. 9. The same reference numbers are used as in Figs. 9 and 11. In addition, lower conduits 37' with exit openings 36' for the electrolyte are also provided, which convey the electrolyte upward from below.
The example in Fig. 15 shows a modification of the example in Fig. 15. The wiping rollers 15 here, analogous to the design discussed in reference to Fig. 8, consist of an inner tube 30 provided with perforations 34 or a tubular expanded metal piece or a tubular wire screen in which the wires are welded at their crossing points, as well as of the discussed coating 31.
Within the tube 30 which encircles its axis 76, there is a non-rotating supply tube 77, into which the electrolyte is introduced in a manner not shown here; the electrolyte then emerges through passage openings (e.g. perforations) or passage slots 78 in the wall of the tube 77 which are arranged one behind the other in the longitudinal direction of the tube. Of course, the supply tube 77 with the passage openings or slits 78 extends across the entire length of the tube 30 and thus the entire breadth of the items 8 to be processed. The ''' 2~~~.~04 passage openings or slits 78 point with their inlets or outlets toward the movement path 2-3 of the items 8, so that the electrolyte flowing through these passage openings or slits 78 of the supply tube 77 emerges through the perforations (or corresponding slits) 34 of the tube 30 vertical to the items 8 onto the latter and passes through the drill holes 42.
Thus the flow speed of the electrolyte through the perforations or slits 78 and the perforations 34 causes a corresponding vertical flow through the drill holes 42 of the boards 8 and therefore also causes improvement in the metal precipitation there. In this example, the electrolyte in the supply tube 77 may either be under pressure and pressed through the perforations or slits 78 and the drill holes 42, or else a lower pressure and thus a suction effect is produced in the interior of the tube 77, which draws the electrolyte through the drill holes 42 and the perforations or slits 78. In the latter case, any particles of the wiping coat that have gotten into the drill holes 42 can be removed and carried away via the tube 77 and later filtered out of the extracted electrolyte. Of course, in the example in Fig. 15 as well as in the other example, a series of holes 34 are distributed continuously around the circumference of the roller 30. The aforementioned tube 77 can be located in a wiping roller or above or under the items to be processed. Pressure rollers or disks 64 are also shown here, which rotate around the axis 64' and serve as support roller or transport rollers for the items 8 conveyed through.
Fig. 8 shows, schematically, above a flat item 8 provided with~drill holes 42, e.g., a printed circuit board, a wiping roller 15 in the form of a flooding anode, which corresponds to the parts 30, 31, 77, 78 of the example in Fig. 15. These parts are only indicated here in schematic fashion. If a pressure of the electrolyte is formed in the supply tube 77, the electrolyte flows downward, according to the arrows, through the drill holes 42. If, on the other hand, an underpressure is created in the tube interior 77, then the electrolyte flows opposite to the indicated arrow direction. This example shows, as counter or pressure rollers, two counter rollers 48 driven in the arrow direction and thus also in the transport direction 3 of the board 8, which rollers leave such a broad space 60 free under the perforations or slits 78 of the supply pipe 77--and thus in the flow direction of the electrolyte--that the electrolyte can flow unobstructed between the counter rollers 48. l~lonetheless, due to the arrangement of two counter rollers symmetrical to the wiping roller 15, even distribution of the pressure of the wiping roller 15 on the counter rollers 48 is ensured. These counter rollers are provided on their surface with insulation, or else they consist of plastic.
In longitudinal section, Fig. 17 shows the example of a flooding anode shown only schematically in Figs. 15 and 16 and identified by the reference numbers 30, 31, 77, 78. The same reference numbers are used as in Figs. 5, 6, 15 and 16. Reference is made to the associated descriptions of these figures. The flooding anode 30, 31, 77, 78 depicted in the upper area of Fig. 17 can be moved in the vertical direction against the pressure of springs 23 with its bearings and its drive shaft 49. This permits height compensation, so that boards 8 of varying thickness can be processed. The current feeds occur via clips 9, 11, which are connected to one pole of the rectifier and connect the latter to the items to be processed, as well as through loop contacts 50, which are connected to the other rectifier pole and connect the latter to the drive shaft 49 of the flooding anode.
Furthermore, there is a pressure or counter roller 51 consisting, at least on its surface, of a material that is not electrically conductive and provided at its circumference with drainage grooves 52, whereby these grooves ~~.~:160~~
FROM : TEL: JtatJ.25.1995 10:10 HM P19 WC) 94/03f~55 1'C:T/I~E93/OOG84 farm an angle, hcrt nn acme angle,wit:h the longitudinal axis 53 of Lhls rollt.r 51. Jn this way, the tlecarolytt crncrginl; tlrrwnw:trel frc~tn the drill holes 4z iv c.:onvcyed away. .In this cast, as tlrc arrows show, the c~lectrrrlyte is conveyed through pressure in arrow direc.~tion 55 and, ;,cc~ordin~, try the: arr~rws SA, is pawed tlrou~;h t he l,rrfcrraticmx ar slits 78 and then through the drill hales 42 and c:c~nduct.ed into the drain;tgc t;roovcs ~2. Instead of tltis, it. is also possible far sucaicm to occur at the upper end 77' of the flood tube olpnsite to the:
dircctioo of the arrrrw 55, by n,ean5 f~~ whic;h the clcctrolyte is dravtrn upward from the drainage grooves 52 through the holes 7R and apposite to the arrow dirccaion S4. '1'Ite flooding anode is drivrn by its shaft 49 in a rcaational direction (see arrow 57) opposite trj t:hc rotational direction (;rrrow S8) of the drive shaft 5G of the cotmtc.r roller 5l. 'T'hr, reference nutnbc:r 50 indicates a loop contact of the current suprly t:o the; drive shaft ~9. The flooding anode is cxluippcd at one end with inn4r and outer sidc~ slide bearings 59 and 59' for the 30 and the Drive shaft 49, rrspeccivcly. '!'he aforementioned slide bearings 59, 59' are located nn the circumference or on the inner diameter of a seationary bearing shell 79, which is held via a stay 80 on a frame crf this ~trrangc~mer,t not described in tnorc detail and is conduct:ad so as t.o be vertically movable in a recess 81 by a certain path segment.
1n the case of printed circuit boards in which the drill hole walls arc first coated only with a ccmduct.ive layer that cannot tolerate larger' currc~.nt densities, lower currem densities arc t:o he used at the beginning in t:hc first part of the processing section G (see Fig, 3). Once a sufficient mct.al layer has been deposited thercy, then, aS ItL.It7S 1l,UVe through Section G in direction 2-3, thr.. current dcnsit:y of the galvanirat.ion process is increased by measures that arc known in themselves.
The process and the arrangement according to the invention arc also suitable for the processing of flat items ~1~~~0~

which are suspended vertically in treatment baths and remain there during the treatment. In this way, the inventions provides not only for continuous runs of the items to be processed, but also for discontinuous operation, in which the items are placed in a station and undergo processing there. During this processing, wiping and flooding are carried out.
Thus "periodic"
wiping and flooding take place during the periods of the bath treatment in question.
All depicted and described features and their combination with one another are essential to the invention for different design forms. Features and details described in one of the examples can also be used analogously in other examples.

Claims

1. A process for electrolytically processing a flat perforated item, comprising the steps of moving the item in a transport direction to a treatment station where the item is contacted with an electrolyte;
continuously mechanically wiping, in the presence of one of a cathodic item and an anode, and an anodic item and a cathode, a surface of the item using means for reducing the thickness of a diffusion layer depleted in metal ions adjacent the surface of the item, which means include a wiping roller extending perpendicular to the transport direction over the entire width of the item and in contact with the item; and moving the electrolyte in a direction substantially perpendicular to a plane of the item as the item emerges from the wiping roller so as to direct the electrolyte only toward the perforations in the item to convey the electrolyte through the perforations in the item under pressure.

2. The process as in claim 1, wherein the wiping step comprises contacting the wiping roller, which forms part of the reducing means, directly on the surface of the item in a sliding manner to disturb and at least partially destroy the diffusion layer, and further comprising moving the item and the wiping roller relative to one another.

3. The process as in claim 2, comprising creating the relative movement by a transport movement of the item to the wiping roller.

4. The process as in claim 2, wherein the item is cathodic and the wiping roller is anodic, the relative movement step comprising moving the cathodic item relative to an anode wiping roller, which has a coating of a material that absorbs the electrolyte and allows it to permeate, and bringing the coating directly into contact in a sliding fashion on the surface of the item to be processed, while in order to reduce the diffusion layer in the perforations of the item moving the electrolyte at the same time substantially perpendicular to the plane of the item to be processed so that the electrolyte is conveyed through the perforations.

5. The process as in claim 4, wherein coating on the wiping roller is a resilient coating that can be flattened or pressed.

6. The process as in claim 1, comprising wiping at least a portion of one surface of the item.

7. The process as in claim 2, wherein the relative speed between the items and the wiping roller is substantially zero.

8. The process as in claim 2, wherein the relative movement step comprises imparting to a contact area of the wiping roller which contacts the surface of the item, an independent movement which deviates from the transport movement in at least one of speed and direction.

9. The process as in claim 1, wherein both sides of the item are wiped by separate wiping rollers, the rollers rotating in opposite directions.

10. The process as in claim 1, wherein both sides of the item are wiped by separate wiping rollers, the rollers rotating in a common direction.

11. The process as in claim 1, comprising increasing a current density of a galvanizing current during the course of the movement of the item through the treatment station.

12. The process as in claim 1, comprising sucking the electrolyte through the perforations.

13. The process as in claim 1, comprising wiping the surface and conducting the electrolyte through the perforations from below a surface level of a bath of the electrolyte and thus within the electrolyte.

14. An arrangement for electrolytically processing a flat item having perforations and a width, comprising:
treatment means for applying electrolyte to the item;
means for transporting the item through the treatment means in a transport direction along a planar transport path;
means for contacting and reducing the thickness of a diffusion layer depleted in metal ions adjacent the surface of the item, the reducing means comprising a wiping roller arranged perpendicular to the transport direction, and configured so as to wipe at least one surface of the item across the entire width; and means for conveying the electrolyte only toward the perforations in the item under pressure in a flow substantially perpendicular to the planar transport path as the item emerges from the wiping roller so as to force the electrolyte through the perforations.

15. The arrangement as in claim 14, and further comprising an anode connected to the wiping roller for applying metal.

16. The arrangement as in claim 14, wherein the wiping roller is provided with a coating that is configured to contact the surface of the item at least during a relative movement between the item and the wiping roller.

17. The arrangement as in claim 16, wherein the wiping roller is configured and arranged to extend over the entire surface area of the item, at least the item being movable relative to the wiping roller.

18. The arrangement as in claim 16, wherein the coating is configured to contact the surface of the item with an adjustable pressure force.

19. The arrangement as in claim 16, wherein the coating is an open-pore plastic that is liquid-permeable.

20. The arrangement as in claim 16, wherein the coating is an elastic material.

21. The arrangement as in claim 16, wherein the wiping roller has a circumference which is provided with the coating, and further comprising drive means for rotating the wiping roller in a rotational direction and at a circumferential speed which are selectable in order to produce a relative speed between a bearing region of the wiping roller and the surface of the item.

22. The arrangement as in claim 21, wherein the wiping roller comprises one of a perforated metal tube, an expanded metal tube and a wire screen tube, and a cylindrical coating surrounding the tube so that the electrolyte is suppliable and extractable from inside the tube.

23. The arrangement as in claim 22, wherein the tube is configured to conduct the electrolyte through an interior of the tube, a passage for the electrolyte being formed between the tube interior, the tube wall and the coating surround the tube.

24. The arrangement as in claim 23, wherein a series of passage openings is provided in the tube wall.

25. The arrangement as in claim 22, wherein the tube has passage openings for the electrolyte, a supply tube for the electrolyte being arranged inside the tube, the supply tube having passage openings that point toward the item, the supply tube and the tube being configured to extend across the entire width of the item.

26. The arrangement as in claim 25, wherein the supply tube is arranged so that the passage openings are in close proximity to the planar transport path on which the item is transported.

27. The arrangement as in claim 25, wherein the supply tube is arranged in the tube in a non-rotating fashion.

28. The arrangement as in claim 25, wherein the tube and the supply tube located therein are provided so as to be movable substantially perpendicular to the planar transport path.

29. The arrangement as in claim 21, wherein the wiping roller comprises a metal tube and a cylindrical coating surround the tube, one of an expanded metal and a wire screen being arranged between the tube and the cylindrical coating so as to hold the coating and tube to one another, electrolyte running from a point outside the wiping roller to the perforations of the item.

30. The arrangement as in claim 21, wherein the conveying means comprises means for generating a fluid stream of electrolyte toward the perforations in the item, and further comprising a pressure roller arranged opposite to the wiping roller, the wiping roller contacting one surface of the item and the pressure roller contacting the other surface of the item.

31. The arrangement as in claim 30, wherein pairs of opposing wiping and pressure rollers are arranged behind one another in the transport direction, whereby, in alternating fashion, in one pair a wiping roller is provided above the item and a pressure roller is provided below the item and in a next pair, a wiping roller is provided below the item and a pressure roller is provided above the item.

32. The arrangement as in claim 30, wherein at least one tube with openings for the electrolyte is arranged between two wiping rollers, and further comprising a collection device provided below the item for collecting the electrolyte.

33. The arrangement as in claim 30, wherein the pressure roller is provided with drainage grooves which serve for extraction of the electrolyte.

34. The arrangement as in claim 21, wherein at least one pair of opposing wiping rollers are provided so that one of the rollers is located above the item and the other roller is located below the item.

35. The arrangement as in claim 16, wherein the coating has a thickness of 1 to 4 mm.

36. The arrangement as in claim 14, wherein the conveying means comprises pressure-producing means for supplying the electrolyte to the perforations in the item.

37. The arrangement is in claim 14, wherein the conveying means comprises means for sucking the electrolyte through the perforations in the item.

38. The arrangement as in claim 14, and further comprising a flow nozzle adapted to inject the electrolyte through perforations located in an area of an opening of the flow nozzle, whereby a backflow of the electrolyte through other perforations occurs in an edge area of the flow nozzle due to a vacuum that exists on the underside of the item, the flow nozzle being configured to extend across the entire breadth of the item.

39. The arrangement as in claim 38, and further comprising anodes located within the flow nozzle in a pre-chamber surrounded by a housing to which the electrolyte is supplied.

40. The arrangement as in claim 38, and further comprising a suction device arranged on an exit side of the perforations to which the electrolyte is conducted with pressure by the flow nozzle, the suction device having a housing which is under an underpressure and extends across the entire breadth of the item.

41. The arrangement as in claim 14, and further comprising lower tubes arranged to convey the electrolyte from the bottom of the item upward, the lower tubes having passage openings for the electrolyte directed toward the bottom of the item.

42. The arrangement as in claim 14, and further comprising spring means for pressing the wiping roller against the surface of the item.

43. The arrangement as in claim 14, wherein the transporting means is operative to transport the items in a horizontal position in the treatment means.

44. The arrangement as in claim 43, wherein the transporting means includes clips which can fasten on at least one side edge of the item.

45. The arrangement as in claim 14, and further comprising two counter rollers arranged on one side of the item, and flooding rollers, the flooding rollers and wiping roller being arranged on an opposite side of the item from the two counter rollers and positioned so that a flow-through space is formed between them for the electrolyte.

46. A method of electrolytically treating printed circuit boards, which are provided with perforations and moved through a treatment bath by conveyor means or guided to a treatment station, means for reducing the thickness of a diffusion layer, which is deprived of metal ions, being provided and in contact with the printed circuit boards, the areas of the printed circuit boards to be treated being continuously and mechanically wiped in the presence of an anode and cathodic printed circuit boards or in the presence of anodic printed circuit boards and a cathode, and an electrolyte is moved with a movement component, which is substantially perpendicular to the plane of the printed circuit boards, and is conveyed through the perforations in said boards.

47. A method of electrolytically treating printed circuit boards, which are provided with perforations and moved through a treatment bath by conveyor means or guided to a treatment station, means for reducing the thickness of a diffusion layer, which is deprived of metal ions, being provided and in contact with the printed circuit boards, a relative movement being effected between cathodic or anodic printed circuit boards, and a mechanical wiping device at the anode end or cathode end, said wiping device being brought directly into sliding abutment on the surfaces of the printed circuit boards in order to disturb and at least partially destroy the diffusion layer, and the electrolyte is moved with a movement component, which is substantially perpendicular to the plane of the printed circuit boards, and is moved through the perforations in said boards.

48. The method according to claim 47, characterized in that the above-mentioned relative movement is created by a conveyor movement of the cathodic or anodic printed circuit boards relative to the wiping device at the anode end or cathode end.

49. The method according to claim 47 or 48, characterized in that the movement of the cathodic printed circuit boards is effected relative to the wiping device at the anode end, which device has a coating formed from a material which absorbs the electrolyte and permits it to pass therethrough, and in that the coating is brought directly into sliding abutment on the surfaces of the printed circuit boards in order to disturb, or at least reduce the thickness of the diffusion layer, while the electrolyte is simultaneously moved with a movement component substantially perpendicular to the plane of the printed circuit boards to reduce the diffusion layer in the perforations in the printed circuit boards and is moved through the perforations in said boards.

50. The method according to any one of claims 46 to 49, characterized in that either one surface is wiped, or both surfaces of the printed circuit boards are wiped.

51. The method according to any one of claims 47 to 50, characterized in that the wiping device at the anode end has an inherent movement at its abutment location or area relative to the surface of the printed circuit boards, which movement differs in size and/or direction from the conveyor movement.

52. The method according to any one of claims 47 to 51, characterized in that, in the case of a two-sided treatment of the printed circuit boards, their speed relative to the wiping device on a first surface is directed in opposition to a second wiping device on a second surface.

53. The method according to claim 52, characterized in that in the case of a two-sided treatment of the printed circuit boards, their speed relative to that of the wiping devices on their two surfaces is oriented in the same direction.

54. The method according to any one of claims 47 to 53, characterized in that the speed of the printed circuit board relative to the speed of the wiping device is minimal.

55. The method according to any one of claims 47 to 54, characterized in that a pressure of the wiping device is exerted upon the printed circuit boards.

56. The method according to any one of claims 49 to 55, characterized in that, with the presence of a resilient coating of the wiping device, the coating is compressed or pressed.

57. The method according to any one of claims 46 to 56, characterized in that, during the course of the movement of the printed circuit boards through the treatment bath, the current density of the galvanising current is increased.

58. The method according to one of claims 46 to 57, characterized in that the electrolyte is guided through the perforations with pressure.

59. The method according to any one of claims 46 to 58, characterized in that the electrolyte is sucked from the perforations by means of reduced pressure.

60. The method according to any one of claims 46 to 59, characterized in that the wiping of the areas and the guidance of the electrolyte through the perforations are effected internally of the bath fluid.

61. An arrangement for electrolytically treating printed circuit boards, which are provided with perforations and move through a treatment bath by conveyor means or guided to a treatment station, means for transporting said printed circuit boards to a treatment station, means for reducing the thickness of a diffusion layer, which is deprived of metal ions, being provided and in contact with the material being treated and wherein means for wiping the surface or the surfaces of either cathodic or anodic printed circuit boards are provided, and means are also provided for moving the electrolyte in a flow through the perforations in the printed circuit boards, which flow extends substantially perpendicular relative to the plane of said boards.

62. The arrangement according to claim 61, characterized in that a wiping device is provided on the anode for the coating of metal.

63. The arrangement according to claim 61, characterized in that a wiping device at the anode end or cathode end is provided with a coating and abuts against the surfaces of the cathodic or anodic printed circuit boards, at least during relative movement between printed circuit board and wiping device.

64. The arrangement according to claim 63, characterized in that the wiping device or a plurality of wiping devices extends or extend over the entire width, which extends substantially at right angles to the direction of conveyance, or over the periphery of the conveyed printed circuit boards, and at least the printed circuit boards are displaceable relative to the wiping device.

65. The arrangement according to claim 63 or 64, characterized in that the coating abuts against the surfaces of the printed circuit boards with an adjustable compression force.

66. The arrangement according to any one of claims 63 to 65, characterized in that the coating is formed from a material, which is chemically resistant to the electrolyte.

67. The arrangement according to claim 66, characterized in that the coating is formed from an open-pored plastics material, which is permeable to fluids and wear resistant.

68. The arrangement according to claim 66 or 67, characterized in that the coating is formed from a resilient material.

69. The arrangement according to any one of claims 62 to 68, characterized in that the wiping device comprises at least one wiping roller, the periphery of which is provided with a coating, in that a drive is provided for rotating at least one wiping roller, the direction of rotation and/or circumferential speed of which roller is selectable to produce a relative speed between the abutment location or abutment area of the wiping device and the surfaces of the printed circuit boards.

70. The arrangement according to claim 69, characterized in that the wiping roller or the wiping rollers comprises or comprise a perforate, metallic tube or an expended metal tube or a wire grating tube and a cylindrical coating, which surrounds the wiping roller, the electrolyte being supplied or discharged internally of the tube, expanded metal or wire grating tube.

71. The arrangement according to claim 69, characterized in that the wiping roller or the wiping rollers comprises or comprise a metallic tube and a cylindrical coating, which surrounds the wiping roller, the coating and tube being held together by an expanded metal, situated therebetween, or by a wire grating, and in that the electrolyte is supplied from a location externally of the wiping roller or wiping rollers to the perforations in the printed circuit boards.

72. The arrangement according to any one of claims 69 to 71, characterized in that situated opposite a wiping roller, which abuts against a surface of the printed circuit boards and is provided with flow coating means, there is a pressure roller, which abuts against the other surface.

73. The arrangement according to claim 72, characterized in that, in the case of a two-sided galvanization of the printed circuit boards, pairs of oppositely situated rollers are disposed one behind the other when viewed with respect to the direction of treatment, whereby, alternatively with a first pair, a wiping roller provided with flow-coating means is provided above the printed circuit boards and a pressure roller is provided beneath said printed circuit boards, and, in the case of a second pair, a wiping roller provided with flow-coating means is provided beneath the printed circuit boards and a pressure roller is provided above the printed circuit boards.

74. The arrangement according to any one of claims 69 to 71, characterized in that at least one pair of wiping rollers are provided opposite one another, whereby one of the rollers is situated above the printed circuit boards and the other roller is situated beneath said printed circuit boards, and the flow direction of the electrolyte is the same in both wiping rollers.

75. ~The arrangement according to any one of claim 70 or 71, characterized in that the electrolyte is guided in the interior of the tube of a wiping roller, and the electrolyte passes between the tube interior, the wall thereof and the coating surrounding the tube.

76. ~The arrangement according to claim 75, characterized in that a number of through-apertures are provided in the tube wall.

77. ~The arrangement according to claim 70 or 71, characterized in that, internally of the rotating tube which is provided with through-apertures for the electrolyte, a feed pipe, which guides the electrolyte, is provided with through-apertures or through-slots, whereby the through-apertures or through-slots are oriented with their through-end faces towards the path of movement of the printed circuit boards, and in that the feed pipe as well as the rotating tube extend over the entire width of the path of the printed circuit boards.

78. ~The arrangement according to claim 77, characterized in that the through-apertures or through-slots of the feed pipe are situated as close as possible to the printed circuit boards.

79. ~The arrangement according to claim 77 or 78, characterized in that the feed pipe is mounted in a non-rotating manner in the tube.

80. ~The arrangement according to any one of claims 77 to 79, characterized in that the rotating tube, together with the feed pipe situated therein, is displaceably mounted substantially perpendicular relative to the plane of the printed circuit boards.

81. ~The arrangement according to any one of claims 69 to 80, characterized in that one or more tubes with apertures for the electrolyte is or are provided for supplying the electrolyte to the spaces between two wiping rollers, and in that collecting devices for the electrolyte are provided beneath the spaces.

82. The arrangement according to any one of claims 61 to 81, characterized in that pressure-producing means are provided for supplying electrolyte to the perforations in the printed circuit boards.

83. The arrangement according to any one of claims 61 to 82, characterized in that means are provided for sucking the electrolyte from the perforations in the printed circuit boards.

84. The arrangement according to claim 82 or 83, characterized in that a baffle nozzle is provided for galvanising printed circuit boards, which are provided with perforations, said nozzle urging the electrolyte through perforations, which are situated in the region of the baffle nozzle aperture or slots while the electrolyte is returned through other perforations in the edge region of the baffle nozzle by means of a reduced pressure of the underside of the printed circuit boards, the baffle nozzle extending over the entire width of the printed circuit boards to be treated.

85. The arrangement according to claim 84, characterized in that anodes are situated internally of the baffle nozzle.

86. The arrangement according to claim 84 or 85, characterized in that a suction device is situated on the outlet side of the perforations, to which the electrolyte is supplied with pressure through the baffle nozzle, the housing of said suction device being under reduced pressure and extending over the entire width of the printed circuit boards to be treated.

87. The arrangement according to any one of claims 61 to 80 and 82 to 86, characterized in that lower tubes, which convey the electrolyte upwardly from below, are provided with through-apertures.

88. The arrangement according to any one of claims 61 to 87, characterized in that a wiping device or wiping devices abut against the respective surfaces of the printed circuit boards with resilient force.

89. The arrangement according to any one of claims 61 to 88, characterized in that the printed circuit boards to be treated are placed and guided in a horizontal position in the treatment station.

90. The arrangement according to claim 89, characterized in that conveyor means are provided for the conveyance of the printed circuit boards in a horizontal position, such means gripping at least one of their lateral edges.

91. The arrangement according to any one of claim 72 or 73, characterized in that the pressure rollers, which are situated opposite a wiping roller in the form of a flow-coating roller, are provided with drainage grooves, which serve to conduct the electrolyte away.

92. The arrangement according to claim 91, characterized in that two counter-rollers are mounted opposite the wiping and flow-coating roller on the other side of the printed circuit boards and are so positioned that they form therebetween a throughflow chamber for the electrolyte, such chamber either being urged by pressure from the flow-coating roller into the perforations in the printed circuit boards or being sucked into the flow-coating roller through the perforations by means of suction.

93. The arrangement according to any one of claims 63 to 68, characterized in that the thickness of the coating is 1 to 4 mm.

94. The arrangement according to any one of claims 61 to 93, characterized in that various wiping devices are provided in combination with one another for the electrolytic treatment of the same printed circuit boards.

95. The method according to claim 54, wherein the relative speed between printed circuit board and wiping device tends to be zero.

96. The arrangement according to any one of claims 61 to 94 for accomplishing the method according to any one of claims 46 to 60.

97. The arrangement according to claim 66, wherein said material is a plastics material.

98. The arrangement according to claim 85, wherein the anodes are situated internally of a preliminary chamber which is surrounded by a housing and to which the electrolyte is supplied.

99. The arrangement according to claim 90, wherein said conveyor means are clamps.