EP2412501B1 - Device for coating workpieces - Google Patents

Description

The invention relates to a device for coating workpieces.

In the coating of narrow sides of plate-shaped products by means of so-called edge bands edge band and plate are brought together to form a joint gap in a joint zone and firmly connected to each other, wherein edge band and workpiece are thereby moved relative to each other. In this case, the edge band is transferred to an adhesive state. This has been achieved in the past by a hot melt application. Meanwhile, it is state of the art to melt a functional layer of the edge band before joining to the workpiece by radiation and then to connect by pressure with the workpiece.

In addition to laser radiation, plasma radiation has recently also been used to melt the functional layer. A generic device is eg from the DE 20 2009 009 253 Ul known. The functional layer of the edge band is heated with a radiation or flame emerging from a plasma nozzle. Especially with the use of plasma technology, the distance between edge band and plasma nozzle is important in order to achieve an optimal melting result. Likewise, it is important to make the melting of the functional layer over its surface as homogeneous as possible, since otherwise the activation and consequently the connection with the workpiece takes place unevenly, which in particular can locally lead to the edge band after joining on the workpiece can solve this again. On the one hand, this can happen because the functional layer is incompletely melted and can not develop its adhesive action; on the other hand, too intensive exposure of the plasma radiation / flame can cause the functional layer to burn and likewise no longer fulfill its function.

In relative movement between edge band and workpiece, therefore, the edge band is guided past the plasma nozzle, so that in the longitudinal direction of the edge band, a homogeneous irradiation is realized. However, it is also important to realize the irradiation homogeneously over the transverse direction of the edge band. This is not possible with a nozzle which has a round opening cross-section. Although it is possible to arrange a plurality of nozzles in the transverse direction of the edge band side by side, however, the nozzles can not be placed arbitrarily close to each other due to space constraints, so that in the exiting rays or flames adjacent nozzles usually remains too low radiation intensity left to sufficiently melt the functional layer , Consequently, one makes do with a diagonal arrangement of the nozzles, as they are in the FIG. 2 is shown. The edge band 2 is guided in the direction X, the nozzles 3a are arranged at an angle to the edge band 2 in a row, which is indicated by the dashed line D. Thus, it can be achieved that the individual nozzles 3a or their effective regions on the edge band 2 in the transverse direction Z of the edge strip 2 move closer to one another than would be the case with a perpendicular to the longitudinal or feed direction X of the edge strip 2. However, this configuration also has shortcomings. Conversely, the improvement of the homogeneity in the direction Z leads to a deterioration in the homogeneity in the direction X, since the material sections of the edge band 2 melted by the individual nozzles 3a on the way to the point P, at which it comes into contact with the workpiece, have different distances have covered. In other words, the portion of material (in the region of the upper edge 2a) heated by the front nozzle 3a in series D travels a lesser distance to P and is warmer than the portion of material heated by the nozzle D in the row D (in the region of the lower nozzle) Edge 2b). The resulting temperature gradient is disadvantageous.

The object of the present invention is therefore to provide a device for coating workpieces, in which the mentioned disadvantages are at least reduced.

This object is achieved by a device having the features of claim 1. Advantageous embodiments can be found in the subclaims.

According to the invention, it is provided in a first embodiment to arrange the plasma nozzles in at least two rows extending diagonally to the feed direction. There are at least two rows of nozzles provided, which are oppositely inclined, so that, for example, results in a V-shaped arrangement of the plasma nozzles. It is important in every case that so many nozzles are provided,
that in each case the coating material lies over its full width in the effective range of the plasma nozzles.

According to a further embodiment, provision is made for the openings of at least one plasma nozzle to be slit-shaped or slot-shaped, with an opening longitudinal extent, which takes place substantially transversely to the feed direction such that the coating lies completely within the effective range of the plasma nozzle. It can be provided in succession in the feed direction a plurality of nozzles with different sized or long nozzle openings in order to work with the effective range of the plasma nozzles different width coatings can.

Preferably, the plasma nozzles of all embodiments can be turned on or off individually in order to be able to use in particular coatings such as edge bands or the like with different widths transversely to the feed direction.

• Figur 1 zeigt eine schematische Ansicht der erfindungsgemäßen Vorrichtung als Draufsicht.
• Figur 2 zeigt eine Plasmadüsenanordnung nach dem Stand der Technik.
• Figur 3 zeigt eine nicht erfindungsgemäße Plasmadüsenanordnung.
• Figur 4 zeigt eine weitere erfindungsgemäße Plasmadüsenanordnung.

The invention will be explained in more detail below with reference to the embodiments in the drawing figures 1 and 4. The invention generally relates to the application of coatings to workpieces. The term edge band is used below by way of example, but not restrictively, and the term plate is used for the workpiece.

• FIG. 1 shows a schematic view of the device according to the invention as a plan view.
• FIG. 2 shows a plasma nozzle assembly according to the prior art.
• FIG. 3 shows a non-inventive plasma nozzle assembly.
• FIG. 4 shows a further inventive plasma nozzle assembly.

In the FIG. 1 the coating process or the device used for this purpose is shown. The plate 1, whose narrow side is to be coated with the edge band 2, is fed in a direction X '. From a magazine is transported via a feeder 6 usually stored on a roll edge band 2 in the direction X towards the plate 1 and added in the region of a joining zone F to the narrow plate side and pressed against the plate 1 by means of printing tools such as the pinch roller 4, wherein the pressure primarily perpendicular to the direction X 'of the plate 1 in a direction Y' is exercised. P describes the area at which the edge band 2 contacts the panel 1 at the end of the joining zone F. To connect plate 1 and edge band 2, these are moved relative to each other. Before joining, a functional layer (not shown) provided on the edge band is activated. This is done by irradiating the same with a plasma source 3 which generates plasma jets and / or a flame which emerges through plasma jets (referred to below as nozzles) 3a in the direction of the edge band 2 (essentially in the direction Y transverse to the direction X) and to strike at the same thing. The distance between the edge band 2 and the plasma source 3 can optionally be varied, either by moving the source 3 or by moving the guide 5 of the edge band 2 opposite the plasma source 3 by the irradiation With the plasma jets emerging from the jets 3a and the flames generated therefrom, the edge band 2 is melted up or melted in the region of its functional layer as a result of the heat development, thereby rendering it "sticky" or liable. The so-melted edge band 2 is pressed against the narrow side of the plate 1 as described above. The functional layer solidifies and melts with the plate 1.

For the arrangement of the plasma nozzles 3a, the in FIG. 4 geometry selected.

In FIG. 3 are two (not necessarily parallel) nozzle rows D with the nozzles 3a and D 'shown with the nozzles 3a', which are angled or inclined to the running direction X of the edge strip 2 and to its transverse direction Z and in particular with the direction X about the angle form α or α '. By this arrangement is opposite to in FIG. 2 As shown in the prior art (see above) during the passage of the edge band through the area between the plasma source 3 and guide 5, a larger area of the edge band 2 in the effective region of the plasma nozzles 3a, 3a ', so that the melting is more effective. In particular, this arrangement achieves an overlap of the effective range of the nozzles of the row D and those of the row D ', which are not available in the prior art. In particular, banding in the longitudinal direction X on the edge band 2 can be reduced by varying the heat input over the width of the edge band. This can also be done by moving the rows of nozzles, such as the row D 'opposite to in FIG. 3 shown Configuration is offset by half the distance A (Z component of the distance between two nozzles 3a) in the Z direction. As a result, overlap the effective ranges of the individual nozzles, so that a more homogeneous melting of the functional layer of the edge strip 2 is possible. It is also alternatively or additionally possible, the entire nozzle assembly, which is preferably provided on a block to vibrate in the Z direction, move or swing to achieve the spaces between "stripes" on the edge band 2.

An inventive plasma nozzle arrangement is in the FIG. 4 where also combinations with the in FIG. 3 embodiment shown are conceivable. The possibilities of vibration, of movement or of the oscillation of the nozzles 3a, 3a ', 3a "are additionally conceivable in this embodiment FIG. 4 the two nozzle rows D, D "are inclined in opposite directions so that they form approximately a V-shape, the legs of which form the individual nozzle rows, whereby (as is generally possible also in the above embodiments not according to the invention), the nozzles can also be individually activated resp It is essential that the nozzles can be activated so that the edge band over its entire width, which is defined by the distance in the Z direction between its upper edge 2a and its lower edge 2b, in the effective region of the plasma nozzles 3a, 3a "(this applies to all embodiments discussed here). In the example shown, the outermost nozzles of the V-shape, the nozzles 3b and 3b "are in the region of the upper edge 2a and the lower edge 2b, respectively. FIG. 2 well-known single-row form, that thereby the The distance between the first and the last nozzle in the running or feed direction X can be reduced, whereby the initially mentioned temporal offset between the heating of the edge region located in the effective region of the frontmost nozzle and the heating of the regions located further behind can be reduced and a more homogeneous melting result can be achieved. In addition, the in FIG. 4 shown arrangement much more flexible, especially if wider edge bands 2 are to be used.

Claims (8)

1. Device for coating workpieces (1) of wood or wood substitutes with a coating (2), more particularly for edging the narrow sides of plate-type workpieces (1) with an edging strip (2), wherein the device has a contact pressure roller (4) and a joining zone (F) as well as a plasma source (3) with plasma nozzles (3a; 3a"), by means of which a function layer of the coating (2) is heated or activated and by pressing against the workpiece (1) in the region of the joining zone (F) by means of the contact pressure roller (4) is connected to the workpiece (1) through relative movement along a feed direction (X) of the workpiece (1) and coating (2), characterised in that the plasma nozzles (3a; 3a") are arranged one behind the other in a first row (D) and in at least one second row (D; D"), wherein the first and the second row of plasma nozzles (3a; 3a") each extend at an angle (α; α") to the feed direction (X), wherein at least two rows (D, D") form the two arms of an approximately V-shaped arrangement of plasma nozzles (3a; 3a") wherein the span of the V-shaped arrangement is selected so that the width of the coating (2) defined between two opposite sides (2a, 2b) of the coating (2) running in the feed direction can lie completely within the active region of the plasma nozzles (3a; 3a").
2. Device according to claim 1 characterised in that the angles (α; α") of the first and second row of plasma nozzles (3a; 3a") to the feed direction are the same size.
3. Device according to claim 1 or 2 characterised in that the plasma nozzles are mounted on a nozzle block (3).
4. Device according to one of the preceding claims characterised in that a guide device (5) is provided for the coating (2), wherein the guide device (5) faces the plasma nozzles (3a; 3a") and is designed so that the coating (2) guided through the guide device is held at a defined distance from the plasma nozzles (3a; 3a").
5. Device according to claim 4 characterised n that the relative distance between the coating (2) and plasma nozzles (3a; 3a") is variable.
6. Device according to one of the preceding claims characterised in that the plasma nozzles are designed so that they can be switched on or off individually or in groups.
7. Device according to one of the preceding claims characterised in that the plasma nozzles are arranged movable perpendicularly to the feed direction (X) in order that they can be set in vibration.
8. Device according to one of the preceding claims characterised in that the row of nozzles (D, D') are arranged off-set relative to one another in the direction (Z) transversely to the feed direction (X).

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