EP2612710B2 - Painting system component having a surface coating - Google Patents

Description

The invention relates to a bell cup for a rotary atomizer, according to the preamble of claim 1. The invention also includes a corresponding manufacturing method.

Rotary atomizers, which have a rotating bell cup as the application element, are usually used to paint motor vehicle body components. The problem here is the fact that the bell cup is heavily soiled with the applied paint during the painting operation, both on the outer surfaces (e.g. lateral surface) and on the inner surfaces (e.g. overflow area), with the paint sometimes adhering very strongly to the surface of the bell cup. When changing the coating agent, a relatively large amount of detergent must therefore be used to clean the bell cup of the adhering residues of the old coating agent, which also requires a relatively large amount of time. This also applies to the so-called short rinsing, which is carried out between the coating of individual coating objects (e.g. motor vehicle bodies). The disadvantage of the conventional bell cups is the tendency to get dirty and the unsatisfactory cleanability.

In addition, the surfaces, in particular the overflow surfaces, of the conventional bell cup are subject to wear due to corrosion and/or abrasion, which increases the surface roughness, which in turn increases the requirements for cleaning the bell cup.

Out of DE 101 12 854 A1 it is known to coat the surface of such a bell cup in order to increase abrasion resistance and thereby reduce wear. However, these known surface coatings do not solve the problem of the tendency towards contamination or the lack of cleanability of the bell cup.

Furthermore, the prior art should be noted U.S. Patent No. 5,923,944 , GB 2 170 226 A , EP 0 435 312 A1 , WO 03/064720 A1 and EP 0 087 836 A1 . However, these publications do not disclose any painting system components and belong to a completely different technical field.

The invention is therefore based on the object of reducing the tendency of a bell cup to become soiled and/or to improve the ability of the bell cup to be cleaned.

This object is achieved by a bell cup according to the invention according to the main claim.

Within the scope of the invention, it is provided that a bell cup has a surface layer which reduces the tendency to become soiled and/or improves the ability to be cleaned.

Within the scope of the invention, the base body itself can consist, for example, of aluminum or an aluminum alloy, titanium, steel, stainless steel, non-ferrous metal (copper and its alloys), ceramic, plastic or a combination of these materials.

Within the scope of the invention, the surface layer can contain oxides, nitrides and/or carbides, with the surface layer containing tantalum, niobium and/or vanadium.

In a preferred exemplary embodiment of the invention, the surface layer consists of a material based on Si—O, Si—OH or silicon-organic compounds, in particular in the form of a nanolayer, as will be described in detail below.

In addition, it should be noted that the surface layer preferably contains metal oxides, metal nitrides or metal-organic compounds.

It should also be mentioned that the surface layer can optionally consist of an organic, in particular metal-organic material, or of an inorganic material.

Depending on the coating agent to be used, the surface layer can be either hydrophilic or hydrophobic. A hydrophilic surface layer is characterized by a contact angle with water that is smaller than 90°, 45°, 20°, 10°, 8° or even smaller than 6°. In addition, the surface layer can even be superhydrophilic, with the surface layer is then characterized by a contact angle to water of less than 5°, 3°, 2° or even less than 1°. In the case of a hydrophobic surface layer, on the other hand, the contact angle with respect to water is preferably greater than 90°, 110°, 130° or 150°. It is even possible within the scope of the invention for the surface layer to be superhydrophobic, with the contact angle to water being greater than 160°, 180°, 200° or even 220°.

Furthermore, within the scope of the invention, there is the possibility that the surface layer is a so-called nano-layer. Such nanolayers are known per se from the prior art and therefore do not need to be described in more detail. At this point, it should only be mentioned that nano layers usually consist of nanoparticles with a size of less than 100 nm, which settle in the surface roughness and thereby seal the surface, which leads to a significantly reduced surface roughness. A lotus effect of the component surface can also be realized with such a nano-layer, which leads to a self-cleaning component surface. The term nanolayer used in the context of the invention is therefore preferably based on a surface layer that contains particles whose particle size is in the nanometer range. However, there is also or alternatively the possibility that the nanolayer has a layer thickness that is in the nanometer range.

Furthermore, within the scope of the invention, there is the possibility that the surface layer has a microstructure in order to reduce the tendency to soiling. For example disclosed WO 96/04123 A1 a self-cleaning component surface that combines a microstructure with a hydrophobic coating to achieve the self-cleaning effect. The content of this patent application is therefore to be attributed to the present description in its entirety.

In addition, the surface layer according to the invention can fulfill a further technical function in that the surface layer is, for example, wear-reducing, which is evident from the patent application already cited at the outset DE 101 12 854 A1 is known.

In a variant of the invention, the base body and the surface layer consist of the same starting material, with the material properties of the surface layer being changed in a targeted manner in order to reduce the tendency of the bell cup to become soiled and/or improve cleanability. For example, the surface of the base body can be blasted for this purpose with blasting techniques (eg water jets, ceramic bead blasting, glass beads, etc.) in order to change the surface properties accordingly. Alternatively, there is the possibility that the surface of the base body is irradiated with a laser or etched to produce the desired material properties. Furthermore, within the scope of this variant of the invention, there is the possibility that the surface layer is produced by plasma processes, for example by plasma-electrolytic oxidation (PEO technology).

In another variant of the invention, the base body and the surface layer consist of different starting materials, with the surface layer being applied to the base body as a surface coating. For example, this application of the surface layer can be done by physical vapor deposition (PVD: Physical Vapor Deposition) or by other methods.

Other possible methods for applying or creating the surface layer are chemical vapor deposition (CVD: Chemical Vapor Deposition), etching, laser irradiation, ion implantation, blasting techniques (e.g. water jets, ceramic bead blasting, glass bead blasting) and classic coating methods such as spraying, dipping, atomizing, brushing, which are particularly suitable for applying organic surface layers.

In order to achieve special surface layers, it can be useful within the scope of the invention to apply several superimposed partial layers with different material properties, the superimposed partial layers being able to differ, for example, with regard to ductility, friction, wettability, surface roughness, corrosion resistance or wear resistance.

Furthermore, within the scope of the invention, there is the possibility that the surface layer has a plurality of regions which are separate from one another and have different properties. In an area that is subjected to high mechanical loads, the surface layer can, for example, be optimized more for the greatest possible abrasion resistance, whereas good cleanability in such areas has a lower priority. In surface areas that are heavily exposed to the paint and are also difficult to access, the surface layer, on the other hand, can primarily be optimized for the lowest possible tendency to soiling, whereas abrasion resistance in these areas only has a lower priority.

Furthermore, it should be mentioned that the surface layer can consist of a material with a high, medium or low surface friction.

The same also applies to the wettability of the surface layer, which can optionally consist of a material with very good, good or low/poor wettability.

There are also various options within the scope of the invention with regard to ductility, which can be selected depending on the application. For example, the surface layer can consist of a material with a high ductility, in particular with an elongation at break of more than 5% or 10%. Alternatively, however, there is the possibility that the surface layer consists of a material with medium ductility, in particular with an elongation at break of between 0.5 and 5%. Furthermore, there is also the possibility that the surface layer consists of a material with low ductility, in particular with an elongation at break of less than 0.5%, 0.3% or 0.1%.

Above that, the surface layer consists of a material with a low roughness (i.e. Rz<10µm).

There are also various options with regard to abrasion resistance, so that the surface layer can optionally consist of a material with high, medium or low abrasion resistance.

Furthermore, there are also various possibilities with regard to the corrosion resistance of the surface layer depending on the application, so that the surface layer can optionally consist of a material with a high, medium or low corrosion resistance.

Corrosion resistance is particularly important when the bell cup consists of non-ferrous metal (copper and its alloys), since non-ferrous metals also corrode in connection with deionized water (DI water). This is important because deionized water is contained in water-based paints and washing-up liquids, so bell cups made of non-ferrous metals must be coated with a corrosion-resistant surface layer.

The possibilities of the material properties mentioned above can also be combined with one another in a targeted manner in order to achieve certain properties.

For the finest possible atomization of the coating agent, it is advantageous, for example, to combine the following material properties of the surface layer with one another: low interfacial friction, low wettability, high ductility, low roughness, high abrasion resistance and low corrosion resistance.

To achieve the best possible cleanability, however, it is advantageous to combine the following material properties with one another: medium surface friction, high wettability, medium ductility, low roughness, low abrasion resistance and very good corrosion resistance.

To achieve corrosion protection for aluminum, on the other hand, it is advantageous to combine the following material properties with one another: medium surface friction, low wettability, high ductility, low roughness, low abrasion resistance and very good corrosion resistance.

In a variant of the invention, the cleaning-optimizing surface layer covers the entire surface of the base body.

In another variant of the invention, on the other hand, the cleaning-optimizing surface layer only covers the outer surfaces of the base body. In the case of a bell cup, the lateral surface and/or the back of the base body are then preferably covered with the surface layer.

In a further variant of the invention, on the other hand, only an inner surface of the base body is covered with the surface layer. It can be a bell plate be an overflow surface, for example.

In a further variant of the invention, however, the surface layer covers the surface of the base body only in partial areas that require optimization of the cleaning properties. For example, this can be the areas of the lateral surface and the overflow surface that are directly adjacent to the spray-off edge.

In addition, it should be mentioned that the invention is not limited to a single bell cup that is optimized in terms of its tendency to become soiled or its ability to be cleaned. Rather, the invention also includes a rotary atomizer with a bell cup optimized according to the invention and a complete painting robot with such a rotary atomizer.

Finally, the invention also includes a production method for producing a bell cup optimized according to the invention, as can already be seen from the above description.

Figur 1

eine Querschnittsansicht eines erfindungsgemäßen Glockentellers an einem Rotationszerstäuber,

Figur 2

eine Querschnittsansicht eines erfindungsgemäßen Glockentellers, bei dem die Oberflächenschicht nur Teile des Glockentellers abdeckt,

Figur 3

eine Querschnittsansicht eines erfindungsgemäßen Glockentellers, bei dem die Oberflächenschicht die äußere Mantelfläche und die Rückseite des Glockentellers überzieht,

Figur 4

eine Querschnittsansicht durch ein anderes Ausführungsbeispiel eines erfindungsgemäßen Glockentellers, wobei die Oberflächenschicht den gesamten Glockenteller überzieht, sowie

Figur 5

eine Querschnittsansicht eines erfindungsgemäßen Glockentellers, bei dem die Oberflächenschicht nur die Innenfläche und die Überströmfläche des Glockentellers überzieht.

Other advantageous developments of the invention are characterized in the dependent claims or are explained in more detail below together with the description of the preferred exemplary embodiments of the invention with reference to the figures. Show it:

figure 1

a cross-sectional view of a bell cup according to the invention on a rotary atomizer,

figure 2

a cross-sectional view of a bell cup according to the invention, in which the surface layer covers only parts of the bell cup,

figure 3

a cross-sectional view of a bell cup according to the invention, in which the surface layer covers the outer lateral surface and the back of the bell cup,

figure 4

a cross-sectional view through another embodiment of one according to the invention bell cup, with the surface layer covering the entire bell cup, as well as

figure 5

a cross-sectional view of a bell cup according to the invention, in which the surface layer covers only the inner surface and the overflow surface of the bell cup.

figure 1 shows a largely conventional bell cup 1 for a rotary atomizer 2, the bell cup 1 rotating about an axis of rotation 3 during operation.

The paint to be applied is fed to the bell plate 1 through a paint tube and then strikes a baffle plate 4 axially, which deflects the paint in the radial direction.

The paint then flows along an overflow surface 5 to an annular spray edge 6, at which the paint is sprayed.

In addition, the bell cup 1 has a conical lateral surface 7 on its outside, which is also known per se from the prior art.

The invention now provides that the bell cup 1 is coated on its surface with a surface layer which reduces the tendency to soiling and improves the ability to be cleaned. This surface layer is applied to the overflow surface 5 and the paint-carrying inner surfaces of the bell cup 1 and also extends over the entire lateral surface 7. However, it is also possible within the scope of the invention for the entire surface of the bell cup 1 to be sealed with the surface coating .

In this exemplary embodiment, the surface layer according to the invention contains a nano-layer which implements a lotus effect, so that the bell cup 1 is self-cleaning and only needs a short cleaning if necessary.

The embodiment according to figure 2 largely corresponds to the exemplary embodiment described above, so that to avoid repetition, reference is made to the above description, with the same reference symbols for corresponding details be used.

A special feature of this exemplary embodiment is that the bell cup 1 has a surface layer 8 only in the area of its spraying edge 6 , the surface layer 8 being located both on the overflow surface 5 and on the lateral surface 7 lying on the outside.

In addition, there is also an area 9 on the inner surface of the bell cup 1, which is provided with a surface layer which reduces the tendency to soiling and improves the cleanability.

The embodiment according to figure 3 again largely corresponds to the exemplary embodiments described above, so that, in order to avoid repetition, reference is made to the above description, with the same reference symbols being used for corresponding details.

This exemplary embodiment is characterized in that the surface layer only covers the outer lateral surface 7 and the back of the bell cup 1, whereas the overflow surface 5 and the inner surface of the bell cup 1 remain uncoated.

The embodiment according to figure 4 again largely corresponds to the exemplary embodiments described above, so that reference is made to the above description in order to avoid repetition.

This exemplary embodiment is distinguished in that the bell cup 1 is completely sealed with the surface layer 8 . This means that the entire surface of the bell cup 1 is covered by the surface layer 8.

The embodiment according to figure 5 largely corresponds to the exemplary embodiments described above, so that reference is made to the above description in order to avoid repetition.

A special feature of this embodiment is that only the overflow 5 and the inner surface of the bell cup 1 is coated with the surface layer.

The invention is not limited to the preferred embodiments described above. Rather, a large number of variants and modifications are possible, which also make use of the idea of the invention and therefore fall within the scope of protection.

Reference list:

1

bell plate

2

rotary atomizer

3

axis of rotation

4

baffle plate

5

overflow area

6

spray edge

7

lateral surface

8th

surface layer

9

coated area

Claims (10)

1. Bell plate (1) for a rotary atomiser, having

   a) a base body (1) and

   b) a surface layer (8) at least on a part of the surface of the base body (1),

   c) wherein the surface layer (8) reduces the tendency to contamination of the bell plate (1) and/or improves the cleaning capability of the bell plate (1),
   characterised in

   d) that the surface layer (8) contains at least one of the following materials:

   d1) niobium,

   d2) vanadium,

   d3) tantalum, and

   e) that the surface layer (8) consists of a material with a low level of roughness, specifically with a roughness value of less than 10µm.
2. Bell plate (1) according to claim 1, characterised in that the surface layer (8) contains at least one of the following materials:

   a) oxides,

   b) carbides,

   c) nitrides.
3. Bell plate (1) according to claim 1 or 2, characterised in that the surface layer (8) contains at least one of the following materials:

   a) metal oxide,

   b) metal nitride,

   c) an organometallic compound.
4. Bell plate (1) according to one of the claims 1 to 3, characterised in that the base body (1) consists of one of the following materials or of a combination of the following materials:

   a) aluminium or an aluminium alloy,

   b) titanium,

   c) steel, in particular high grade steel,

   d) non-ferrous metal, in particular copper or a copper alloy,

   e) ceramic material,

   f) plastics.
5. Bell plate (1) according to one of the preceding claims, characterised in

   a) that the surface layer (8) is a nanolayer which contains particles with a particle size in the nanometre range, and/or

   b) that the surface layer (8) is a nanolayer which has a layer thickness in the nanometre range,

   c) that the surface layer (8) has a microstructure, and/or

   d) that the surface layer (8) is wear-reducing.
6. Bell plate (1) according to one of the preceding claims, characterised in that the surface layer (8) is created by one of the following methods:

   a) plasma methods, in particular plasma-electrolytic oxidation,

   b) jet techniques, in particular water jets, ceramic bead jets, glass bead jets, or

   c) laser irradiation,

   d) etching,

   e) physical gas phase deposition,

   f) chemical gas phase deposition,

   g) spraying,

   h) dipping,

   i) sputtering,

   j) spreading.
7. Bell plate (1) according to one of the preceding claims, characterised in

   a) that the surface layer (8) comprises a plurality of sublayers having different properties, lying over one another, and/or

   b) that the surface layer (8) comprises a plurality of regions that are separate from one another and have different properties.
8. Bell plate (1) according to one of the preceding claims, characterised in

   a) that the surface layer (8) consists of a material with a high ductility, specifically an elongation at failure of more than 5% or 10%, or

   b) that the surface layer (8) consists of a material with a medium ductility, specifically an elongation at failure of between 0.5% and 5%, or

   c) that the surface layer (8) consists of a material with a low ductility, specifically an elongation at failure of less than 0.5%, 0.3%, or 0.1%.
9. Bell plate (1) according to one of the preceding claims, characterised in

   a) that the surface layer (8) covers only outer surfaces of the base body (1), in particular a lateral surface and/or a rear side of the base body (1), or

   b) that the surface layer (8) covers only an inner surface of the base body (1), in particular a flow-over surface, or

   c) that the surface layer (8) covers the surface of the base body (1) only at partial regions.
10. Manufacturing method for a bell plate (1), comprising the following steps:

    a) providing a base body (1),

    b) generating a surface layer (8) at least on a part of the surface of the base body (1),

    c) wherein the surface layer (8) reduces the tendency to contamination of the bell plate (1) and/or improves the cleaning capability,
    characterised in

    d) that the surface layer (8) contains at least one of the following materials:

    d1) niobium,

    d2) vanadium,

    d3) tantalum, and

    e) that the surface layer (8) consists of a material with a low level of roughness, specifically with a roughness value of less than 10µm.

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