DE19511900A1 - Electro-immersion lacquer coating appts. for small components and loose material - Google Patents

Abstract

The appts. for immersed electro-lacquering of small components and loose material, with an electrically conductive surface, uses a continuous belt (1) with or without perforations as the conveyor and contact system. Pref. the belt has projecting contours, pref. projecting pockets, is electrically conducting and is pref. made of non-rusting material with increased fatigue strength under repeated bending stresses.

Description

The invention relates to a device for electro-dip painting with a endless metal belt strap, this for transportation or the contacting of the parts to be coated in the area parts supply, dip painting, permeate rinsing, demineralized water rinsing, Paint drying and post-treatment is responsible. From the Germans Publications 38 43 544; 42 05 672; 41 42 997; 43 18 780 are Devices known which electro-dip painting of small parts, Screws, nuts and fittings on one connected as an electrode Belt conveyor, or drum conveyor, or as an electrode switched feed hopper, enable. During the painting process, the Changed the contact points of the parts to be coated one or more times, by moving the parts on or in the transport pad. A such a change in the contact points during the painting process enables one nationwide access of the dip coating on the substrate. The The position of the parts on the transport pad can be changed at known continuous immersion painting systems through baffles, change of position the parts against each other, jerky shaking, or by changing the Reach contact points.

The transport documents are made of stainless steel, as a spiral wire belt with a round or triangular profile, as a slat belt with elevations provided surface, as with bristle bands, or as a screw conveyor formed with mushroom-shaped contacts.

State of the art is a continuous dip painting with subsequent Baking the paint in a baking oven, the coated Divide on a stable baking temperature Transport document.  

The transfer between the transport pad of the electrophoretic Dip painting and the subsequent transport document for Rinsing stations and the baking oven, requires a sensitive mechanical Solution, which should prevent mechanical damage that the known systems over a slide loaded with water, by comb-like interlocking of lamellar belts with and without Transfer combs, or by falling transfer between two Conveyor belts in the paint bath, was released.

The invention has the process engineering task of a complete, Comprehensive electro-dip painting with insignificant technical Allow expenses while taking advantage of a Metal belt with corresponding perforation in its surface is used for the entire coating and drying process.

According to the invention the object is achieved by a metal band in Sheet thicknesses between 0.05 and 1.02 mm with one-sided from the metal strip protruding tin pockets, in geometric shapes, as preferred Semicircles, triangles, half ellipses, quadrilaterals or polygons that too Contact coated parts directly and transport them gently.

The density, contour and size of those protruding from the metal strip Bags are largely shaped, shaped and contoured painted parts determined. The outstanding pockets are pad and Contact points of the parts to be coated and at the same time the resulting breakthroughs in the metal band for a uniform Flooding of the dip lacquer during the coating process and for a quick drain of the paint when it emerges from the paint bath used. The pockets protrude from the metal band different heights, so that depending on the size and contour of the coating parts, at least a secure three-point support  is guaranteed. A necessary change of the contact points is in the reached the first turning point in the paint bath. This rearrangement enables Coating the support points, which up to this point Were contact points. The contact points, which according to the invention one Make knife rest the same and change at turning points a full area access of the dip lacquer to the Substrate.

The protruding pockets of the metal tape give the one to be coated Share a secure hold throughout the paint job and Drying process.

The flexibility of the perforated metal band enables a flat one Entry angle, which has a decisive influence on minimization of the required paint volume.

The extension angle is designed to be very small to the coated parts not to damage this place because at this time the However, deposited paint on the substrate does not yet adhere is branded.

The metal belt is coated according to the process, but it is conceivable through special surface features, such as with a Plastic coating an adhesion of the dip coating to the surface, that do not serve to support parts or make contact. It only builds up a layer thickness in the case of a plastic coating in the area of parts support points, or the Contact points, whose electrical resistance, at repetitive coating processes is so high that no further An increase in the layer thickness is to be expected.

Since the metal band has no joints or similar places, is a Introducing cured ones from the metal belt surface  dissolving paint residues in the paint bath, in the circumferential process, not possible.

The invention is explained in more detail below by means of the system parts shown in the drawings:
(Two pages of drawings)

Fig. 1 is a system history of the metal belt band described in an electric-pass dip coating;

Figure 2 as a detail the transport pad in the form of a perforated metal belt.

Fig. 1 shows a metal belt with semicircular perforation ( 1 ) in an endless state, which is used as a transport base for the coating and drying process. After appropriate pretreatment, the parts to be coated are applied in a single-layer layer in section ( 2 ) and then inserted at a flat angle into the electro-immersion pool ( 3 ). At the turning point between section ( 3 ) and ( 4 ), caused by the changed transport vector and the perforation of the metal belt band, the loaded parts are forced to move, whereby the contact points and contact points are changed on the inlet side, so that the previously uncoated contact points and contact points subsequently the section ( 4 ) made accessible to the dip lacquer and can thus be coated. Section ( 4 ) can also be used to install additional backdrops, which can cause the contact points to be changed again. The perforation of the metal belt and the initial properties of a metal belt, shown in section ( 5 ), enable a very flat transport course of the parts to be coated in the turning points on generous radii. In section ( 6 ) there is a permeate rinse, which removes loose paint particles that do not adhere to the substrate and metal belt band. In section ( 7 ) the surface is neutralized as a result of a fully demineralized water rinse. Then, shown in section ( 8 ), the coated parts, the lacquer layer of which is water-insoluble and highly viscous at this point, are baked. During this stoving phase, it is conceivable to install a forced rearrangement of the parts to be stoved, caused by further backdrops, which promotes extensive polymerization of the coating.

In the further course, there is a cooling phase shown in section ( 9 ), followed by a discharge area ( 10 ) of the coated parts, the surface of which has hardened and leave the metal belt band.

Since, according to the method, there is the possibility of dragging adhering paint particles on the surface of the metal belt that have passed through the previous process, the metal belt in section ( 11 ) is subjected to a cleaning process in the form of a permeate bath and then neutralized in a demineralized water bath. The deflection points ( 13 ) are continuously floating to avoid increased tension in the metal belt. A clean contact pad is made possible in section ( 14 ) by brushing or grinding off the uppermost contact points of the contours protruding from the metal strip.

Fig. 2 shows in detail a metal belt ( 1 ) with a protruding from the surface of the belt, visible in the form of a perforation of pockets ( 1 D). The size and contour of the pockets protruding from the metal band is determined by the size and contour of the parts to be coated. Possible and procedurally necessary deflection points of the metal belt, shown in positions ( 1 A) and ( 1 B), show a change in the contact and contact points ( 1 C; 1 G) in the reversal points of the metal belt. The transport drive of the system requires safe points of attack, which is ensured by circular openings ( 1 E). The bending line ( 1 F) of the perforation protruding from the metal belt in a semicircle is offset by 90 ° to the transport direction ( 1 H), advantageously characterized in that the initial bending fatigue strength of the metal belt is largely maintained. The semicircular perforation ( 1 D) protruding from the metal belt band causes a deliberate breakthrough ( 1 J) in the metal band, advantageously characterized by guaranteeing the flooding of the dip lacquer and, associated therewith, a uniform grip of the dip lacquer on the substrate to be coated.

Claims (9)

1. Device for electrodeposition of small parts and bulk materials with an electrically conductive surface by means of an endless or endlessly connected metal belt band ( 1 ), with or without perforation, serving as a transport and contact pad. 2. Device according to claim 1, characterized in that the Metal belt band with an outstanding contour, preferably with protruding pockets. 3. Device according to claim 1, characterized in that the Metal belt band is electrically conductive and preferably made of rustproof Material with increased fatigue strength. 4. The device according to claim 2, characterized in that the protruding pockets preferably have knife-like elevations, advantageously characterized in that the parts to be coated, in each Position, point contact with the metal belt. 5. The device according to claim 2, characterized in that the outstanding Leave the contour, openings in the metal belt.   6. The method characterized in that the metal belt with or is designed without a perforation serving for the transport drive and is driven by this. 7. Device characterized in that the bending radius of the protruding pockets run at right angles to the direction of transport, advantageously characterized by the original fatigue strength of the metal belt as far as possible. 8. The device characterized in that the texture of the Metal belt runs in the direction of transport, advantageous thereby characterized to achieve increased bending fatigue strength. 9. The device according to one or more of the preceding claims, characterized in that the surface of the metal belt is not the parts support and not the contact, one of the Process process can receive suitable plastic coating.