DE102020123740A1 - Process and device for the electrostatic coating of metal strips - Google Patents

Abstract

The invention relates to a method for electrostatically coating a metal strip (1) with a coating material (2) using at least one nozzle bar (3), the metal strip (1) being moved in the longitudinal direction relative to the at least one nozzle bar (3), the at least one nozzle bar (3) has at least one slot nozzle with a nozzle gap (3A) which at least partially covers the metal strip (1) moving in the longitudinal direction in the transverse direction, between the at least one nozzle bar (3) and the metal strip (1) via a voltage source ( 4) an electrostatic field is generated and the metal strip (1) is electrostatically coated at least over part of the area with at least one coating material (2). The task is to provide a method for electrostatically coating a metal strip with a coating material and a corresponding device with which the application of the layer on the metal strip can be adjusted with less effort and the metal strip can be coated with fewer rejects for a method in that a plurality of controllable dosing means (5) are used, which are distributed on the at least one nozzle bar (3) in its longitudinal direction and with which, using a control signal, a local change in the size of the nozzle gap (3A) of the at least one nozzle bar (3) can take place during the coating.

Description

The invention relates to a method for electrostatically coating a metal strip with a coating material using at least one nozzle bar, the metal strip being moved in the longitudinal direction relative to the at least one nozzle bar, the at least one nozzle bar having at least one slot nozzle with a nozzle gap, which in the longitudinal direction moving metal strip is at least partially covered in the transverse direction, an electrostatic field is generated between the at least one nozzle bar and the metal strip via a voltage source and the metal strip is electrostatically coated at least over part of the area with at least one coating material using the at least one nozzle bar. In addition, the invention relates to a device for electrostatically coating a metal strip with a coating material, in particular with industrial oils or forming aids, the device having means for carrying out a relative movement of the metal strip in the longitudinal direction relative to at least one nozzle bar, the at least one nozzle bar moving the metal strip in its transverse direction at least partially covered and an electrostatic field is generated via a voltage source between the at least one nozzle bar and the metal strip.

The electrostatic coating of metal strips using at least one nozzle bar is known, for example, from US patent US7626602B2 famous. The property right deals with a device for the electrostatic coating of, for example, a metal strip with different coating materials and uses two nozzle bars for this purpose, whereby the size of the nozzle gap can be varied using hand wheels. Two-part nozzle bars are used, in which the two parts of the nozzle bars are arranged relative to one another in such a way that they each form a slotted nozzle with a nozzle gap through which the coating medium can emerge. The size of the nozzle gap is changed over the entire length of the nozzle bar using the hand wheel.

When coating metal strips, in particular aluminum or aluminum alloy strips, which are intended for further processing into shaped sheet metal parts, for example motor vehicles, it is important when coating with technical oils, e.g. protective oils or forming aids, to coat the metal strip as evenly as possible. Unlike paintwork, however, varying layer thicknesses of the technical protective oils or forming aids cannot be evaluated by a simple visual inspection. Nevertheless, areas of the metal strip that are uncoated or have an insufficient coating lead to significantly increased rejects during the production of shaped sheet metal parts from the coated metal strips, preferably the aluminum or aluminum alloy strips. The well-known change in the size of the nozzle gap over the entire length of the nozzle bar can only provide a limited remedy here. This makes it possible to coat all areas with a sufficient amount of coating materials. But then there is the problem that there are areas which are coated with significantly too large amounts of coating material.

To adjust the size of the nozzle gap of the slotted nozzle of the nozzle bar, adjusting screws were previously used, which are arranged distributed over the length of the nozzle bar, with which the size of the nozzle gap can then be influenced locally. In order to change a faulty coating, the coating process had to be stopped, the nozzle bar removed from the device and the nozzle bar gap size measured, possibly modified and the nozzle bar reinstalled. Since forming aids and technical oils are usually applied at a relatively high temperature in order to achieve good distribution of the spray application on the metal strip by reducing the viscosity of the application medium, cooling was already associated with a change in the size of the slot nozzle gap. Finally, very small gap sizes of less than 250 µm are used, particularly in the case of technical oils and forming aids. Then the nozzle bar had to be installed again and the nozzle bar had to be heated up and the coating process restarted. On the one hand, the problem here is that the coating process had to be stopped. Since the size of the die gap is corrected when it has cooled down, the corrections were not always successful either, since even small deviations caused a different distribution of the coating, resulting in rejects.

Proceeding from this, the object of the present invention was to provide a method for electrostatically coating a metal strip with a coating material and a corresponding device with which the layer application on the metal strip can be adjusted with less effort and coating of the metal strip possible with less waste.

The above object is achieved according to a first teaching of the present invention for a method for electrostatic coating of a metal strip with a coating material by using a plurality of controllable dosing means which are arranged distributed on the at least one nozzle bar in its longitudinal direction and with which a local change in the size of the nozzle gap of the at least one nozzle bar takes place during the coating using a control signal can.

Via the controllable dosing means, which are distributed in the longitudinal direction on the at least one nozzle bar, it is possible to locally change the size of the nozzle gap of the slotted nozzle of the at least one nozzle bar during the coating process and thus to correct the distribution of the coating material during operation. A local change in the size of the nozzle gap is understood to mean that the gap size is changed in the area of the respective dosing means, with this change not affecting the entire nozzle gap.

According to a first embodiment, the method for electrostatically coating a metal strip is further improved in that the dosing means engage with at least one elastic element of the at least one nozzle bar in such a way that local deformation of the elastic element reduces the size of the nozzle gap of the slot nozzle locally during coating can be changed. Due to the elastic properties of the elastic element, a defined restoring moment can be generated on the dosing means, so that the size of the nozzle gap can be set precisely via the dosing means and thus a local enlargement or a local reduction of the nozzle gap. The restoring moment can be adjusted to the actuating forces of the dosing.

The elastic element can be provided in one piece by the nozzle bar or preferably also be provided as an additional elastic element, for example as a spring steel element. In the latter case, the basic structure of the nozzle beam, which for example also has means for heating and means for supplying the coating material, can be retained. In this respect, the nozzle bar preferably has a first and a second nozzle bar half. If the elastic element is designed as an additional elastic element, for example, this can be arranged between the two halves of the nozzle bar and determine the nozzle gap. By providing a spring steel element, the elastic properties of the spring steel element can be precisely adapted to the formation of the local size of the nozzle gap and/or the dosing means.

The distance between the dosing means on the at least one nozzle bar is preferably a maximum of 100 mm, preferably a maximum of 50 mm. The smaller the distance between the dosing means, the more dosing means can be arranged on the nozzle bar and the more precisely the size of the nozzle gap can be adjusted locally. On the other hand, this also increases the number of dosing means and thus the costs of the device and the effort involved in controlling the dosing means. The size of the dosing means, e.g. the diameter of the dosing means, can preferably be regarded as a limiting factor for the minimum distance between the dosing means.

It has been found that, according to a further embodiment of the method, it is advantageous if the dosing means comprise at least one piezo actuator or linear piezo actuator, with which the local change in the size of the nozzle gap takes place. Piezo actuators can only perform small actuating movements. However, these are carried out with high precision and with high actuating forces. The high actuating forces here enable the gap size of the nozzle bar to be directly influenced. Due to the controllability of the piezo actuators, the size of the nozzle gap and thus the distribution of the coating material can be easily adjusted during coating. Waste can thus be significantly reduced. In particular, it is also easier to set the gap size, since the nozzle bar can be set at the operating temperature when it is ready for operation. Linear piezo actuators are particularly preferably used, the adjustment paths of which allow particularly precise changes in the size of the nozzle gap.

According to a further embodiment of the method, an aluminum alloy strip is coated on one or both sides. Strips for the production of formed sheet metal for motor vehicles, in particular from the aluminum alloys AA5XXX or AA6XXX alloy, are preferably coated with a coating material, in particular technical protective oils or forming aids. The tapes have a preferred thickness of 0.5 mm to 4 mm. Corresponding aluminum strips are preferably subjected to further forming steps for use in motor vehicles, for example deep drawing, flanging, bending, etc., in which the technical protective oils and forming aids significantly improve the forming properties of the strip or sheet and reduce rejects.

According to a next embodiment, protective oils, lubricants, forming lubricants with temperature-dependent viscosity or hotmelts are preferably used as coating materials on the applied metal band. Protective oils are primarily used to protect against corrosion, but also to protect against mechanical damage to the strips or sheets made from them. Forming lubricants are intended to improve the forming behavior of the sheet metal produced from the strip during forming, with forming lubricants having a temperature-dependent viscosity being preferably applied to the metal strip. These can easily be electrostatically sprayed onto the metal strip at elevated temperature and, due to the change in viscosity when they hit the cooler metal strip, adhere well to this metal strip. Forming aids of this type are particularly important for forming sheet metal from aluminum alloy strips, since the forming properties of higher-strength variants are limited, for example, and forming is made significantly easier as a result.

These so-called hotmelts can, for example, be better processed according to the next embodiment of the method in that the at least one nozzle bar is heated at least during the coating of the metal strip. The increased temperature of the nozzle bar affects the viscosity of the coating material, allowing it to be applied with improved precision. The locally adjustable size of the nozzle gap during coating also means that the nozzle bar no longer has to be cooled in order to change the size of the nozzle gap. As a result, a corrected spray application of the coating material can be achieved much more easily with a heated nozzle bar.

Finally, according to an advantageous embodiment of the method, the thickness of the layer of coating material is measured after coating in the ongoing coating process and the dosing means are set, controlled or regulated based on the measured distribution of the amount of coating material on the metal strip surface. Due to the only local change in the size of the nozzle gap of the slot nozzle, the production of rejects during operation can be further reduced by controlling the dosing means. A faulty coating can be corrected without stopping the process or manually intervening.

According to a further teaching of the present invention, the above-mentioned object is also achieved by a device for electrostatically coating a metal strip with a coating material, in particular technical oils or forming aids, in that a plurality of controllable dosing means are provided which are on the at least one nozzle bar in its Are arranged distributed longitudinally, the controllable dosing means being designed to allow a local change in the size of the nozzle gap of the slot nozzle when controlled. A change in the local size of the nozzle gap means an increase or decrease in the nozzle gap of the slotted nozzle, with this essentially only having an effect in the area of a dosing means analogous to the effect of an adjusting screw. The opening width of the nozzle gap of the slot nozzle of the nozzle bar depends on the respective medium. A die gap with a width of 200 μm to 70 μm, preferably 170 μm to 70 μm, has proven advantageous for forming lubricants with temperature-dependent viscosity.

As already stated, the provision of controllable dosing means, which can cause a local change in the size of the nozzle gap of the nozzle bar, can correct the coating of the device for electrostatically coating a metal strip during operation of the device, so that errors and rejects are reduced. At the same time, the coating can be set much better, namely during operation. For example, a nozzle bar that consists of only two parts can also be used.

According to one configuration of the device, the at least one nozzle bar has at least one elastic element for forming the at least one nozzle gap, with the controllable dosing means engaging with the at least one elastic element in such a way that the size of the nozzle gap can be changed locally. A restoring force can be automatically provided via an elastic element, with which the size of the nozzle gap can be varied precisely and with repeat accuracy. The elastic element can be provided by the nozzle bar, for example by one of the two halves of the nozzle bar. If, according to one embodiment, the nozzle bar has at least one additional elastic element, then the nozzle bar can be easily adapted to the dosing means used. The elastic element then preferably extends at least over the length of the nozzle bar that is provided for the coating of the metal strip.

According to a further embodiment, the elastic element is a spring steel element. The spring steel element can provide the elastic properties with high precision and repeatability. In addition, spring steel can also provide chemical stability to the coating materials used.

According to a further embodiment, the distance between the controllable dosing means in the longitudinal direction of the nozzle bar is preferably at most 100 mm, preferably at most 50 mm. The smaller the distance, the more precise the possibility of setting the gap size. However, with an increasing number of controllable dosing means, the outlay for control and the costs for provision become higher.

If the controllable dosing means, according to a next embodiment, include at least one piezo actuator, or preferably at least one linear piezo actuator, robust actuators can be provided that can carry out a precise local change in the nozzle gap with large actuating forces.

Due to the electrostatic coating, there are high voltages on the nozzle bar. Therefore, an isolated transmission element is preferably provided for each dosing means, which locally transmits the size of the nozzle gap to be set by the dosing means to the nozzle bar. In this way, the dosing means can be safely protected from the electrical voltage applied to the nozzle bar.

An insulated sliding cylinder with a push rod can preferably be provided as the transmission element. The sliding cylinder is preferably made of polyamide, which has a high breakdown voltage per layer thickness. The dosing means, preferably a piezo actuator, is thus reliably protected against the electrostatic voltage.

If, according to a next embodiment of the device, means are provided for determining the thickness of the layer of coating material, in particular technical oils or forming aids, on the metal strip after coating in the ongoing coating process, with which the controllable dosing means can be controlled in groups or separately, the possibility exists in To be able to react to faulty coatings as early as possible during operation of the device and to keep rejects as low as possible.

The use of metal strips coated according to the invention with forming aids, in particular aluminum or aluminum alloy strips, in subsequent forming processes, for example for the production of formed sheet metal for a motor vehicle, is therefore advantageous, since the coating quality can be increased with forming aids, for example, and the forming process thus produces less rejects.

• 1 in einer schematischen Schnittansicht eine Vorrichtung zur Durchführung des Verfahren zur elektrostatischen Beschichtung eines Metallbands,
• 2 in einer schematischen Draufsicht weitere Ausführungsbeispiele zur Anordnung eines Düsenbalkens zur elektrostatischen Beschichtung eines Metallbands,
• 3 eine perspektivische Darstellung eines Ausführungsbeispiels eines verwendeten Düsenbalkens mit einem ansteuerbaren Dosierungsmittel,
• 4 in einer perspektivischen Ansicht ein verwendeter Düsenbalken mit einer Mehrzahl ansteuerbarer Dosiermittel und
• 5, 5A in einer Schnittansicht das Ausführungsbeispiel aus 3 inklusive einer vergrößerten Darstellung des Düsenspalts.

The invention will now be explained in more detail below using exemplary embodiments in conjunction with the drawing. In the drawing shows:

• 1 in a schematic sectional view a device for carrying out the method for the electrostatic coating of a metal strip,
• 2 in a schematic plan view further exemplary embodiments for the arrangement of a nozzle bar for the electrostatic coating of a metal strip,
• 3 a perspective view of an embodiment of a nozzle bar used with a controllable dosing means,
• 4 in a perspective view, a used nozzle bar with a plurality of controllable dosing and
• 5 , 5A in a sectional view of the embodiment 3 including an enlarged view of the die gap.

In 1 a device for coating a metal strip 1 with a coating material 2 using at least one nozzle bar 3 is shown first. The exemplary embodiment of the device shows two nozzle bars 3 arranged opposite one another, which are arranged on both sides of the metal strip 1 in order to coat this on both sides. However, a one-sided or non-symmetrical arrangement of nozzle bars 3 is also conceivable.

The metal strip 1 is moved in the longitudinal direction relative to the nozzle bar 3, with the at least one nozzle bar 3 having at least one slot nozzle with a nozzle gap, which at least partially covers the metal strip moved in the longitudinal direction in the transverse direction. The metal strip 1 is coated on both sides, at least partially, with at least one coating material 2 in the present exemplary embodiment. A voltage source 4 generates an electrostatic field between the nozzle bar 3 and the metal strip 1, which is grounded here via the strip rollers. The grounded strip rollers R serve to ground the metal strip. Technical oils or forming aids, in particular forming lubricants, for example with temperature-dependent viscosity, for example so-called hotmelts, are preferably used as coating materials. The at least one nozzle bar 3 is used to apply the technical oils, for example protective oils which protect against corrosion, for example, or the forming lubricants mentioned, to the metal strip using the electrostatic field. The nozzle bars 3 are usually on this heated to a specific temperature to reduce the viscosity of the coating materials.

According to the invention, the nozzle bars in 1 not shown, controllable dosing, which are distributed in the longitudinal direction of the at least one nozzle bar 3 and change the size of the nozzle gap of the nozzle bar 3 locally. Finally is in 1 a means M for determining the thickness of the layer of coating material on the metal strip 1 after coating in the ongoing coating process. Depending on the determined layer thicknesses, the in 1 Not shown dosing of the nozzle bar 3 can be set, controlled or regulated in order to react to errors in the coating in the ongoing coating process.

In 2 is a schematic plan view of an arrangement of a nozzle bar 3, the nozzle gap, the metal strip 1 is completely covered. It is also conceivable to use a different arrangement of, for example, two nozzle bars 3 which only partially cover the metal strip 2 . Both conceivable arrangements of nozzle bars 3 can be arranged on one or both sides of the metal strip 1.

In 3 a nozzle bar 3 with a dosing means 5 is now shown in a perspective view. The two nozzle bar halves 3B and 3C form a nozzle gap 3A of a slot nozzle. The nozzle gap 3A extends in the longitudinal direction of the nozzle bar 3 and has a size. Due to manufacturing tolerances, the size of the nozzle gap 3A can vary depending on the position of the nozzle bar 3 in the longitudinal direction. In 3 only one controllable dosing means 5 is now shown. The bores provided in the nozzle bar 3 for connecting further dosing means 5 show that the dosing means 5 are distributed on the at least one nozzle bar 3 in the longitudinal direction, for example distributed at equal intervals.

The two halves of the nozzle bar 3B and 3C are mechanically connected to one another at the end opposite the nozzle gap 3A, for example screwed together, so that the nozzle gap 3A can be varied via dosing means 5. The restoring force for setting a nozzle gap against the dosing means 5 is provided by the screw connection of the nozzle bar halves 3B and 3C and their elastic properties. The width of the nozzle gap 3A is preferably 200 μm to 70 μm, preferably 170 μm to 70 μm and can vary in the longitudinal direction of the nozzle bar.

In 4 the entire nozzle bar 3 with controllable dosing means 5 is shown in a perspective view. The size of the nozzle gap 3A distributed over the entire nozzle bar 3 can be adjusted locally via the dosing means 5 . This allows the nozzle gap 3A to be adjusted to very small spatial distances during the coating process, so that the quantity of coating material 2 applied locally can be changed during the ongoing process. This allows faulty coatings to be corrected during operation and rejects to be reduced.

5 shows this in a sectional view 4 known embodiment in which the dosing means 5 have a piezo actuator, in particular a linear piezo actuator 6, which can influence the size of the nozzle gap 3A via a transmission element, here in the form of an insulated sliding cylinder 7 with push rods 8. Although piezo actuators 6 can only carry out very small deflections, they have high actuating forces which are capable of causing a corresponding local change in the size of the nozzle gap 3A.

in the in 5 In the exemplary embodiment illustrated, means for temperature control 9 of the nozzle bar are provided in the nozzle bar 3, with which the nozzle bar 3 is heated, for example via a temperature control liquid. In addition, the screw connection of the two nozzle bar halves 3B and 3C via screw 10 can be seen.

In contrast to a 2-part nozzle bar, in the in 5 In the exemplary embodiment shown, there is an elastic element 11 between the nozzle bar halves 3B and 3C, on which the pressure rods 8 of the dosing means 5 exert pressure and engage with it in such a way that the size of the nozzle gap 3A during coating is locally reduced by the local deformation of the elastic element 11 can be changed. The enlarged section 5 12 clearly shows the elastic element 11, on which pressure can be exerted via the sliding cylinder 7 with the pressure rod 8 for elastic deformation.

The distance between the dosing means 5 on the nozzle bar can be a maximum of 100 mm, but also a maximum of 50 mm, so that a large number of dosing means 5 are arranged on the nozzle bar 3 . The smaller the distance between the dosing means 5, the finer the gap size of the slot nozzle can be set locally in order to eliminate faulty coatings.

The elastic element 11 is preferably a spring steel element which is precise in relation to the provided actuating forces, for example the pie zo actuators can be selected or constructed. As a spring steel element, it can provide the necessary elastic properties over a long period of time with a high level of consistency.

the inside 5 The sliding cylinder 7 shown is preferably made of polyamide, which has a high breakdown voltage per layer thickness. This ensures that, despite the high voltage at the nozzle bar, the dosing means 5 are sufficiently decoupled from the electrical high voltage and can be controlled properly. However, other materials from which the sliding cylinders can consist are also conceivable.

Aluminum alloy strips, which are used for the production of formed sheet metal for motor vehicles, are preferably coated with the method according to the invention and the device according to the invention. Corresponding sheets must have a coating of technical oils, protective oils or forming aids, for example forming lubricants, in order to have a predetermined forming behavior during forming. Due to the fact that the size of the nozzle gap 3A of the slot nozzle of the nozzle bar 3 can be changed locally during operation, the layer application of coating material 2 can be corrected during operation in the event of an error. As a result, sheet metal produced from suitably coated strips also produces fewer rejects in the downstream forming process, for example in the production of formed sheet metal for motor vehicles. This applies in particular to aluminum alloy strips, which are typically used in motor vehicles, because these are often formed with the maximum degrees of deformation for the material.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• US 7626602 B2 [0002]

Claims (16)

Method for electrostatically coating a metal strip (1) with a coating material (2) using at least one nozzle bar (3), the metal strip (1) being moved in the longitudinal direction relative to the at least one nozzle bar (3), the at least one nozzle bar ( 3) has at least one slot nozzle with a nozzle gap (3A) which at least partially covers the metal strip (1) moved in the longitudinal direction in the transverse direction, between the at least one nozzle bar (3) and the metal strip (1) via a voltage source (4) an electrostatic field is generated and the metal strip (1) is coated at least partially with at least one coating material (2) electrostatically using the at least one nozzle bar (3), characterized in that a plurality of controllable dosing means (5) are used, which are attached to the at least one Nozzle bar (3) are distributed in the longitudinal direction and with which under use At the end of a control signal, a local change in the size of the nozzle gap (3A) of the at least one nozzle bar (3) can take place during coating. procedure after claim 1 , characterized in that the dosing means (5) are in engagement with at least one elastic element (11) of the at least one nozzle bar (3) in such a way that local deformation of the elastic element (11) increases the size of the nozzle gap (3A) during coating can be changed locally. procedure after claim 1 or 2 , characterized in that the dosing means (5) comprise at least one piezo actuator or linear piezo actuator (6) with which the local change in the size of the nozzle gap (3A) is carried out during coating. Procedure according to one of Claims 1 until 3 , characterized in that an aluminum alloy strip (1) is coated on one or both sides. Procedure according to one of Claims 1 until 4 , characterized in that protective oils, lubricants, forming aids such as a forming lubricant or forming lubricants with a temperature-dependent viscosity are applied to the metal strip (1) as the coating material (2). Procedure according to one of Claims 1 until 5 , characterized in that the at least one nozzle bar (3) is heated at least during the coating of the metal strip (1). Procedure according to one of Claims 1 until 6 , characterized in that the layer thickness of the coating material (2) on the metal strip (1) is measured during the ongoing coating process and the dosing means (5) are controlled based on the measured distribution of the quantity of the coating material (2) on the metal strip surface in groups or individually or be regulated. Device for electrostatically coating a metal strip (1) with a coating material (2), in particular with technical oils or forming aids, in particular for carrying out a method according to one of Claims 1 until 7 , wherein the device has means for performing a relative movement of the metal strip (1) in the longitudinal direction relative to at least one nozzle bar (3), wherein the at least one nozzle bar (3) has at least one slot nozzle with a nozzle gap (3A) which moves the longitudinally moved metal strip (1) is at least partially covered in the transverse direction and a voltage source (4) is provided, with which an electrostatic field is generated between the at least one nozzle bar (3) and the metal strip (1), characterized in that a plurality of controllable dosing means (5 ) are provided, which are distributed on the at least one nozzle bar (3) in its longitudinal direction, the controllable dosing means (5) being designed in such a way that, when activated, they cause a local change in the size of the nozzle gap (3A) of the nozzle bar (3) can perform. device after claim 8 , characterized in that the at least one nozzle bar (3) has at least one elastic element (11) for forming the at least one nozzle gap (3A) and the controllable dosing means (5) are in engagement with the at least one elastic element (11) in such a way that that the size of the nozzle gap (3A) can be changed locally. device after claim 8 or 9 , characterized in that the at least one elastic element (11) is a spring steel element. Device according to one of Claims 8 until 10 , characterized in that the distance between the controllable dosing means (5) arranged on the nozzle bar (3) in the longitudinal direction of the at least one nozzle bar (3) is at most 100 mm, preferably at most 50 mm. Device according to one of Claims 8 until 11 , characterized in that the controllable metering means (5) at least one piezo actuator include, with which a local change in the size of the nozzle gap (3A) can take place during the coating. Device according to one of Claims 8 until 12 , characterized in that for each dosing means (5) there is an insulated transmission member (7, 8) which locally transmits the size of the nozzle gap (3A) to be set by the dosing means (5) to the nozzle bar (3). Device according to one of Claims 8 until 13 , characterized in that an insulated sliding cylinder (7) with at least one push rod (8) is provided as the insulated transmission element, via which the dosing means (5) is in engagement with the nozzle gap (3A). Device according to one of Claims 8 until 14 , characterized in that means (M) are provided for determining the thickness of the layer of coating material (2) on the metal strip (1) after coating in the ongoing coating process, with which using a control unit the dosing means (5) in groups or individually can be controlled. Use of with a method according to claim 1 until 7 Metal strips coated with forming aids, in particular aluminum alloy strips, in a subsequent forming process for the production of formed sheet metal for a motor vehicle.

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