DE1913588B2 - Improved surfaces for galvanising - using removable surface film applied prior to polishing to absorb residues - Google Patents

Abstract

To ensure the complete removal of residues arising from the polishing operation from workpiece surfaces which are to be galvanished, a protective layer consisting of natural rubber, dispersed waxes or alginates is applied to the entire workpiece surface prior to polishing. This is removed partially by the polishing process and partially by subsequent dissolving in water or an organic solvent, when any polishing residues dispersed in the layer are removed as well.

Description

The invention relates to a method for removing polishing residues from workpiece surfaces, especially before electroplating, in which a film-forming protective layer made of vegetable rubber, Wax dispersion or alginates is applied.

The mechanical pretreatment of materials should produce a particularly smooth, clean and flawless finish Surface can be achieved, since only on this the galvanic coatings adhere well.

The galvanic coatings, produced electrolytically, protect the material from corrosion, give the material surface an appearance that is as smooth as possible and generally also shiny and also increase the hardness and! Abrasion resistance of the surface.

In the case of mechanical pretreatments, such as B. polishing, polishing agents are in paste form or liquid state supplied to the polishing tool or the workpiece surface.

The residues that occur during polishing, such as cloth fibers from polishing tools and material particles, mix with the polishing paste and are firmly joined together by the heat generated during polishing, sticky or hardened. These residues settle on the surface to be polished as well as on the back and in the openings, bores and holes in the workpiece. During the polishing process, these residues are only removed from the surface to be polished, but not removed from the rest of the places.

For this reason, the workpieces must be post-treated or before the next processing stage, mostly electroplating. This intermediate treatment is a degreasing with organic solvents such as benzene, carbon tetrachloride or trichlorethylene. It is, well, to avoid or simplify this degreasing step and still ensure that all residues are eliminated.

During the subsequent galvanizing process, the galvanic coating covers both the smooth, polished surfaces as well as the very rough residue and forms a coherent crystalline Layer that envelops the entire surface of the workpiece.

The stronger the connection between the crystalline layer of the galvanic, the better the adhesive strength Precipitation and the Werfcstaffunterlage is. If now tightly removed residues were included in this' layer, the adhesive strength would be very much reduced The binding force between support and base would be at the inclusion points this foreign body is very little or nonexistent, so that it closes even with low mechanical loads on the material or the workpiece a detachment of the precipitates at these points from the material substrate, which occurs of cracks in the galvanic coating

For this reason it is important that all residues are removed before electroplating. The previous degreasing processes are time-consuming, expensive and, moreover, do not offer anything once the guarantee that all residues will be removed. In the degreasing baths usually used, it is mainly residues of this type that can be found Do not or only "remove additional expenses that are located on or under breakthroughs, openings or similar inaccessible steljen or stick it on.

In a known method of cleaning internal metal surfaces of chemical reaction devices Wax and beeswax crystallized out on the inner metal surfaces to be cleaned applied, which formed during the polymerization in the form of film coatings or deposits Dissolves residues. It is also known to apply protective layers to metal surfaces, some of which are provided with a coating in the form of varnish or the like, but not through the paint covered parts of the metal surfaces are protected by the coating. It is about with protective coatings for the inner surfaces of spray-painting crates, in which, for example Car bodies or workpieces are spray painted.

There are also film-forming water-soluble coatings known that the car paint or chrome parts of the Protect cars against insects, dust particles and other soiling. This pollution are washed off together with the water-soluble coatings. For the metallization of work pieces, such as printed circuits, are water-soluble protective layers made from vegetable rubber or alginates are provided, which are applied to the workpieces before the metallization process. These protective layers are removed after the metallization and thus enable a sharp Differentiation between conductive and non-conductive parts of the printed circuit.

It is the object of the present invention to provide a method which avoids a processing step prior to electroplating and the removal of all residues accumulated during the polishing process.

To solve this problem, a method is proposed in which on the entire workpiece surface including the breakthroughs, bores and holes before polishing the protective layer is applied, which of the surfaces to be processed by the polishing process itself and of the other places by dissolving in water or in organic solvents along with the residues removed after polishing.

Applying the protective layer on the whole

Material surface can for example by particles of the workpiece into colloidal and film-forming substances before polishing and electroplating take place. Even stubborn residues, formed from polishing paste, cloth fibers from the polishing discs and Material particles, whereby all parts stick together firmly under the heat that is generated during polishing, do not deposit directly on the workpiece, but on the protective layer. The protective layer but is very light together with the residue

and the after

des 14 von dei 2 «u

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Se «» while polishing firmly sticking to each other

protective layer 14 on the factory Gluing or even

all the residue left by polishing. To-x ₅ together are also dieί not water frangible materials such as alumina ^ corundum, polishing earth and the like, which settle at Poheren to the workpieces and with Bishen _g s agents find with difficulty to remove * <> with the protective layer, rapidly and just lifted off

The invention will in the following description of an application example shown in the drawings for performing the method explained in detail in accordance with the invention, _R u

The figure shows a workpiece 10 with a bore 12, the surface roughness of which is shown greatly enlarged.

Before starting mechanical pre-treatment a protective layer or a protective film 14 is applied, which both a surface 16 to be polished as well as the bore 12 and one mechanically not

penetrates polishing paste 15 together with the cloth fibers

30 | 3 _s X _cnt ? 4 consists, for example, of highly swellable collards or ^r " _{di form water-} soluble films, and adhesion of the residues to the areas of the workpiece that have been treated - after polishing the workpiece is JJ ^ _{ht) the D5E} protective layer 14 ablost ollkommene detachment of the jerk-JA ^ Sl with the protective layer 14 of the _Bo Irun _e 12 and the surface 18 causes ^Bo ^ ^u _w f _r f _{d "n} ° _{ch a very} clean Werkstückober- ^ ™ ^ ™ ^ in the subsequent electroplating "1 Hi _P Haftfestiekeit as well as the durability and Le ^ * '^ XSschen coating essentially inherent to _{foreign matter in}

increases JJ ^ jatane ^ ^ ^ _ß .

lead galvanic layer. Except-

Bader instead.

1 sheet of drawings

Claims (1)

Claim: Method for removing polishing residues from workpiece surfaces, in particular before electroplating, in which a film-forming protective layer made of vegetable rubber, wax dispersion or alginates is applied, characterized in that on d <ir entire Workpiece surface including the breakthroughs, bores and holes in front of the Polishing the protective layer is applied, which of the Haches to be machined through the polishing process itself and the other places by dissolving in water or in organic J5 see solvents along with the residue after polishing is removed.