Method for Automatically Regulating the Size of a Slot of a Nozzle Assembly and Control and/or Regulation System

Abstract

The invention relates to a method for automatically regulating the size of a nozzle discharge slot of a nozzle assembly, wherein the nozzle assembly comprises a first and a second nozzle lip and a nozzle discharge slot arranged between the nozzle lips for setting in a controlled manner a thickness profile of a conveyable melt. A plurality of adjusting elements, in particular a plurality of adjusting pins, coupled to a respective thermoelement, is arranged on the first nozzle lip, the thermoelements being controllable by the regulation in such a way that the slot can be adjusted by the action of a mechanical force from the respective adjusting element on the first nozzle lip, as a result of the expansion or contraction of the thermoelements. At an initial operation of the nozzle assembly for conveying the melt, the adjusting elements for subsequent regulation of the slot size are set uniquely free from play as the initial setting. The invention further relates to a control and/or regulation system.

Claims

1-12. (canceled)

13. A method for automatically regulating the size of a nozzle discharge slot of a nozzle assembly, wherein the nozzle assembly comprises a first and a second nozzle lip and a nozzle discharge slot arranged between the nozzle lips for setting in a controlled manner a thickness profile of a conveyable melt, wherein a plurality of adjusting elements is arranged at the first nozzle lip, which are coupled to a respective thermoelement, wherein the thermoelements are controllable by the regulation in such a way that the slot adjustment can be realized by the action of a mechanical force from the respective adjusting element on the first nozzle lip as a result of an expansion or contraction of the thermoelements, wherein at an initial operation of the nozzle assembly for conveying the melt, the adjusting elements for subsequent regulation of the slot size are set uniquely free from play as the initial setting.

14. The method according to claim 13, wherein a standardized nozzle discharge slot of the nozzle assembly is set by means of the setting of the adjusting elements free from play.

15. The method according to claim 13, wherein the degree of freedom from play of the adjusting elements is set at least depending on the type of melt or depending on the size of a basic slot of the nozzle assembly.

16. The method according to claim 13, wherein the setting of the adjusting elements free from play is achieved by means of a standardized setting of the torque of the adjusting element, wherein the adjusting elements comprise an equal or substantially equal contact pressure against the first nozzle lip.

17. The method according to claim 13, wherein the adjusting elements are set as an initial setting to a maximum opening stroke of the nozzle assembly.

18. The method according to claim 13, wherein the setting of the adjusting elements free from play is at least stored or integrated as a self-learning algorithm for a renewed initial operation of the nozzle assembly.

19. The method according to claim 13, wherein subsequent to the initial setting, the adjusting elements are automatically regulated along the entire width of the nozzle assembly for the slot adjustment.

20. The method according to claim 19, wherein the regulation of the adjusting elements occurs automatically based on measurement signals of at least one sensor, wherein the sensor is at least designed or arranged at the nozzle assembly in such a way that conclusions can be drawn about the thickness profile of the melt, and by comparing the measured thickness profile with a nominal value, a basic control value for the individual adjusting elements can be generated by the regulation so that a deviation from the nominal value is a maximum of 30%.

21. The method according to claim 13, wherein at least two adjusting elements are adjusted simultaneously.

22. The method according to claim 13, wherein an adjustment of the adjusting elements is carried out automatically based on measurement signals of at least one sensor, wherein the sensor is at least designed or arranged at the nozzle assembly in such a way that conclusions can be drawn about the thickness profile of the melt and the right-hand and left-hand edge region of the melt is monitored by means of the sensor and is controlled or regulated in such a way that the respective edge region is set by adjusting the adjusting elements depending on at least the material or quality criteria or a conveying speed.

23. The method according to claim 13, wherein at least one clamping blade is respectively arranged in a right-hand and left-hand edge region of the nozzle assembly, wherein the width of the nozzle discharge slot can be variably set, wherein the method comprises the following steps, which are carried out automatically for adjusting the width of the nozzle discharge slot and for clamping the adjusting elements: unclamping the clamping blade within the nozzle discharge slot; displacing the clamping blade within the nozzle discharge slot; clamping the clamping blade within the nozzle discharge slot for fixing individual adjusting elements.

24. At least a control or regulation system with a control unit for carrying out the method according to claim 13.

Description

[0046] The invention is explained in more detail below on the basis of non-restrictive embodiment examples, which are shown in the figures. The figures show:

[0047] FIG. 1 a schematic view of an inventive nozzle assembly according to a first embodiment;

[0048] FIG. 2 a schematic view of an inventive nozzle assembly according to a further embodiment with a characteristic thickness profile;

[0049] FIG. 3 each a schematic diagram of a regulation according to the invention with a simultaneous and parallel adjustment of the adjusting elements;

[0050] FIG. 4 each a schematic diagram of a regulation according to the invention for the transfer of the setting of the adjusting elements in an edge region.

[0051] In the following figures, similar elements are marked with the same reference signs for reasons of clarity.

[0052] FIG. 1 shows a schematic view of a nozzle assembly 10 according to the invention for an automated regulation of the size of a nozzle discharge slot according to a first exemplary embodiment. The nozzle assembly 10 comprises a first nozzle lip 12 and a second nozzle lip 14. A nozzle discharge slot 16 is arranged between the nozzle lips 12, 14 for the controlled setting of a thickness profile of a conveyable melt. The melt, for example a plastic melt for the production of a flat film, is conveyed through the nozzle discharge slot 16. Depending on the size or height of the nozzle discharge slot 16, the thickness of the melt is set or changed.

[0053] To set the size or height of the nozzle discharge slot 16, a plurality of adjusting elements 20, in particular approx. 120 adjusting elements 20, is arranged on the first nozzle lip 12. Only one adjusting element 20 is shown symbolically in FIG. 1.

[0054] The adjusting element 20 is exemplarily designed as an adjusting pin, which comprises a tapering shape in the direction of the first nozzle lip 12. The tapered shape tapers to a point-shaped tip. The point-shaped tip forms a minimum contact surface between the adjusting element 20 and the first nozzle lip 12. In other words, the adjusting element 20 is connected to the first nozzle lip 12 via the point-shaped tip.

[0055] The adjusting element 20 is coupled with a respective thermoelement 30. When heated, the thermoelement 30 expands and exerts a mechanical pressure on the first nozzle lip 12 via the respective adjusting element 20, causing it to deform at the corresponding location. In particular, the nozzle discharge slot 16 is thus reduced. Furthermore, the thermoelement 30 can compress during cooling and causes a mechanical pull on the first nozzle lip 12 via the adjusting element 20, which increases the nozzle discharge slot 16 at the corresponding location. For this purpose, the thermoelement 30 can be controlled by a nozzle regulation in such a way that that the slot can be adjusted by the action of a mechanical force from the adjusting element 20 on the first nozzle lip 12, as a result of the expansion or contraction of the thermoelement 30. In other words, the thermoelement 30 can exert pressure on the first nozzle lip 12 by means of an exemplary expansion via the adjusting element 20. The design of the adjusting element 20 with its tapered shape leads in particular to a very precise adjustment of the nozzle discharge slot 16, since the effect on adjacent adjusting elements is reduced. The nozzle discharge slot 16 is therefore deformed in a limited spatial region of the first nozzle lip 12. The thermoelement 30 can, for example, be connected to a heating or cooling device, which is controlled by the regulation for heating or cooling the thermoelement 30.

[0056] At the initial operation of the nozzle assembly 10 for conveying the melt, the adjusting elements 20 can be uniquely set free from play for a subsequent regulation of the slot size of the nozzle discharge slot 16 as the initial setting. This has the advantage that an exact alignment of the nozzle discharge slot 16 is possible. If there is too much play in the adjusting elements 20, the heating or cooling of the thermoelements 30 cannot partially lead to a deformation of the nozzle lip 12. In addition, the setting of the adjusting elements 20 free from play allows a reproducible starting point of the nozzle regulation at the initial operation of the nozzle assembly 10. This generally increases the process stability. In particular, the setting free from play can be carried out automatically at the initial operation of the nozzle assembly 10, thus avoiding any manual intervention by an operator.

[0057] For example, at least two adjusting elements 20 can be adjusted simultaneously. This has the advantage that the simultaneous, in particular automatic, adjustment of at least two adjusting elements 20 eliminates the need for a time-consuming manual adjustment of individual adjusting elements one after the other. Likewise, the simultaneous adjustment of two adjusting elements 20, in particular of two adjacent adjusting elements 20, can reduce the transverse influence of the adjusting elements 20.

[0058] Furthermore, an adjustment of the adjusting elements 20 can be carried out automatically based on measurement signals of a non-displayed sensor, wherein the sensor is designed and/or arranged at the nozzle assembly 10 in such a way that conclusions can be drawn about the thickness profile of the melt and the right-hand and left-hand edge region of the melt is monitored by means of the sensor and is controlled or regulated in such a way that the respective edge region is set by adjusting the adjusting elements 20 depending on the material, in particular viscosity and/or viscoelasticity, and/or quality criteria and/or a conveying speed. This has the advantage that the edge region of the melt or film which is outside the net region is explicitly considered and evaluated. By monitoring the edge region of the melt, the entire thickness profile can be optimally set. The edge region can be evaluated with regard to quality and/or stability criteria, in particular depending on the product to be produced and/or the production process.

[0059] Furthermore, at least one clamping blade, not shown, can be arranged in a respective right-hand and left-hand edge region of the nozzle assembly 10, wherein the width of the nozzle discharge slot 16 can be variably set, wherein a method for adjusting the width of the nozzle discharge slot 16 and for clamping the adjusting elements 20 can be carried out automatically and comprises the following steps: [0060] unclamping the clamping blade within the nozzle discharge slot 16; [0061] displacing the clamping blade within the nozzle discharge slot 16; [0062] clamping the clamping blade within the nozzle discharge slot 16 for fixing individual adjusting elements 20.

[0063] This has the advantage that the automatic setting of the clamping blades for a width adjustment of the nozzle discharge slot 16 results in significant time savings in the production process, as no manual adjustment by the operator is required.

[0064] FIG. 2 shows a schematic view of a nozzle assembly according to the invention for the automated regulation of the size of a nozzle discharge slot according to a further exemplary embodiment with a characteristic thickness profile. The nozzle assembly 10 comprises a non-shown first nozzle lip 12 and a non-shown second nozzle lip 14. A nozzle discharge slot 16 is arranged between the nozzle lips 12, 14 for the controlled setting of a thickness profile of a conveyable melt 50. The melt 50, for example a plastic melt for the production of a flat film, is conveyed through the nozzle discharge slot 16. Depending on the size or height of the nozzle discharge slot 16, the thickness of the melt 50 is set or changed.

[0065] For setting the size or height of the nozzle discharge slot 16, a plurality of adjusting elements 20, in particular approx. 120 adjusting elements 20, is arranged on the first nozzle lip 12. Each adjusting element 20 is coupled with a respective thermoelement 30. When heated, the thermoelement 30 expands and exerts a mechanical pressure on the first nozzle lip 12 via the respective adjusting element 20, causing it to deform at the corresponding location. In particular, the nozzle discharge slot 16 is reduced. Furthermore, the thermoelement 30 can compress during cooling and causes a mechanical pull on the first nozzle lip 12 via the adjusting element 20, which increases the nozzle discharge slot 16 at the corresponding location. For this purpose, the thermoelement 30 can be controlled by a nozzle regulation in such a way that the slot can be adjusted by the action of a mechanical force from the adjusting element 20 on the first nozzle lip 12, as a result of the expansion or contraction of the thermoelement 30.

[0066] The outgoing melt 50 conveyed through the nozzle discharge slot 16 is adhered to a casting roll 40 by means of electrostatics in an exemplary manner and can then be wound into a sleeve in a subsequent winding device. Due to the adhesion the melt 50 can be fixed to the casting roll 40. The edge of the melt 50 is characterized by the so-called edge entry (“neck-in”), which is caused by the withdrawal of the melt 50 from the nozzle assembly 10 and the visco-elastic behavior of the melt 50. As a result of the neck-in, a reduction of the film width at the casting roll 40 in relation to the width of the nozzle discharge slot 16, as well as a thickening 70 of the edge region of the film corresponding to this reduction, occurs. The reduction of the film width is represented by the curved dotted lines at the melt 50. The thickening 70 is further exemplarily illustrated by the characteristic thickness profile of the melt 50.

[0067] The y-axis shows the thickness of the melt 50 and the X-axis shows the nozzle width. The thickness of the melt 50 is regulated in such a way that a constant thickness can be optimally achieved along the entire nozzle width. The characterizing thickening 70 of the right-hand and left-hand edge region of the nozzle assembly 10 is caused by the neck-in of the melt 50. Due to the electrostatic edge adhesion to the casting roll 40, a thin section 72 can occur between the thickening 70 and a constant thickness of the melt 50, since the electrostatics attract melt particles from both sides. The characteristics of the thin section 72 depends, for example, on the melt flow distribution at the nozzle discharge slot 16, on the viscoelastic behavior of the melt 50 and on process settings such as the line speed, the length of the melt plume, or the strength of the edge adhesion.

[0068] The thickness profile of the melt 50 is monitored by a sensor, not shown here, as an example. The sensor can be designed as an optical sensor and/or arranged on the casting roll 40, so that conclusions can be drawn about the thickness profile of the melt 50. For this purpose, the sensor is preferably connected to the regulation via data communication for the transmission of measurement signals.

[0069] By comparing the measured thickness profile with a nominal value, a basic control value can be generated by the regulation for the individual adjusting elements 20 so that a deviation from the nominal value is a maximum of 30%, in particular a maximum of 10%, preferably in the range of 2% to 5%. In other words, the regulation can be used to set an essentially constant thickness of the melt 50. For this purpose, the regulation comprises a data processing unit, which is configured in such a way that the measurement signals of the sensor are processed and, based on this, a control signal is generated for the adjusting elements 20 or the respective thermoelements 30 for adjusting the slot of the nozzle discharge slot 16. In other words, the processing of the measurement signals of the sensor results in the automatic control or regulation of individual, several or all adjusting elements 20 of the nozzle assembly.

[0070] At the initial operation of the nozzle assembly 10 for conveying the melt 50, the adjusting elements 20 can be set uniquely free from play for a subsequent regulation of the slot size of the nozzle discharge slot 16 as the initial setting. This has the advantage that an exact alignment of the nozzle discharge slot 16 is possible. In particular, the setting free from play can be carried out automatically at the initial operation of the nozzle assembly 10, thus avoiding any manual intervention by an operator.

[0071] For example, at least two adjusting elements 20 can be adjusted simultaneously. This has the advantage that the simultaneous, in particular automatic, adjustment of at least two adjusting elements 20 eliminates the need for a time-consuming manual adjustment of individual adjusting elements one after the other. Likewise, the simultaneous adjustment of two adjusting elements 20, in particular of two adjacent adjusting elements 20, can reduce the transverse influence of the adjusting elements 20.

[0072] Furthermore, the right-hand and left-hand edge region of the melt 50 can be monitored by means of the sensor and controlled or regulated in such a way that the respective edge region is set by adjusting the adjusting elements 20 depending on the material, in particular viscosity and/or viscoelasticity, and/or quality criteria and/or a conveying speed. This has the advantage that the edge region of the melt 50, which is outside the net region, is explicitly considered and evaluated. By monitoring the edge region of the melt 50, the entire thickness profile can be optimally set. The edge region can be evaluated with regard to quality and/or stability criteria, in particular depending on the product to be produced and/or the production process.

[0073] Furthermore, at least one clamping blade 60 is arranged in a respective right-hand and left-hand edge region of the nozzle assembly 10, wherein the width of the nozzle discharge slot 16 can be variably set, wherein a method for adjusting the width of the nozzle discharge slot 16 and for clamping the adjusting elements 20 can be carried out automatically and comprises the following steps: [0074] unclamping the clamping blade 60 within the nozzle discharge slot 16; [0075] displacing the clamping blade 60 within the nozzle discharge slot 16; [0076] clamping the clamping blade 60 within the nozzle discharge slot 16 for fixing individual adjusting elements 20.

[0077] This has the advantage that the automatic setting of the clamping blades 60 for a width adjustment of the nozzle discharge slot 16 results in significant time savings in the production process, as no manual adjustment by the operator is required. Clamping and/or unclamping of the clamping blades 60 is done thermally in an exemplary manner. The displacement of the respective clamping blade 60 can be motorized and limited to a maximum adjustment torque.

[0078] FIG. 3 shows a schematic diagram of an inventive regulation of the size of a nozzle discharge slot of a nozzle assembly with a simultaneous and parallel adjustment of the adjusting elements. The description of the nozzle assembly 10 is analogous to FIG. 2.

[0079] In both diagrams, the y-axis shows the control value for the individual adjusting elements 20 and the x-axis shows the nozzle width. The individual adjusting elements 20 are represented by a horizontal line. Thus, there are several adjusting elements 20 at a defined distance from each other along the nozzle width. The direction of the arrows shows the adjustment of the adjusting elements 20. An upward adjustment implies a contraction of the thermoelement 30 associated with the adjusting element 20, which causes a mechanical pull via the adjusting element 20 and increases the nozzle discharge slot 16 at the corresponding location. A downward adjustment implies an expansion of the thermoelement 30 associated with the adjusting element 20, which causes a mechanical pressure via the adjusting element 20 and reduces the nozzle discharge slot 16 at the corresponding location. The length of the individual arrows of the adjusting elements 20 describes the size of the control value or the amount of the strength of the adjustment.

[0080] In the diagram above, the regulation effects a simultaneous adjustment of all adjusting elements 20. All adjusting elements 20 are adjusted along the entire nozzle width, in particular also in the right-hand and left-hand edge region. The size of the adjustment is based on the measured thickness profile of the melt 50. To compensate the thickness profile in case of deviations from a constant thickness, in particular in the net region of the melt 50, the adjusting elements 20 are adjusted upwards and downwards.

[0081] In the diagram below, the regulation effects a simultaneous and parallel adjustment of all adjusting elements 20. All adjusting elements 20 are adjusted symmetrically along the entire nozzle width, in particular also in the right-hand and left-hand edge regions. The adjusting elements 20 are adjusted over an equal stroke to increase the nozzle discharge slot 16. In general, the adjustment of the adjusting elements can occur depending on the type of melt and/or depending on the size of a basic slot of the nozzle assembly 10.

[0082] FIG. 4 shows in each case a schematic diagram of an inventive regulation of the size of a nozzle discharge slot of a nozzle assembly for the transmission of the setting of the adjusting elements in an edge region. The description of the nozzle assembly 10 is analogous to FIG. 2.

[0083] In both diagrams, the y-axis shows the control value for the individual adjusting elements 20 and the x-axis shows the nozzle width. The individual adjusting elements 20 are represented by a horizontal line. Thus, there are several adjusting elements 20 at a defined distance from each other along the nozzle width.

[0084] The diagram above shows an example of a specific setting of the adjusting elements 20 for the entire nozzle width. This specific setting can occur depending on the material of the melt, in particular its viscosity and/or viscoelasticity, and/or quality criteria and/or the conveying speed.

[0085] In the diagram below, the specific setting of the adjusting elements 20 in the respective edge region is transferred as an example from the upper diagram to a reduced nozzle discharge slot or a reduced nozzle width. The reduction of the nozzle width is shown by means of the arrows and realized by means of the clamping blades 60. Before displacing the clamping blades 60, an examination can occur to determine whether the specific setting needs to be adapted.

[0086] The above explanation of the embodiment describes the present invention exclusively in the context of examples. Of course, individual features of the embodiment can be freely combined with each other, if technically reasonable, without leaving the scope of the present invention.

LIST OF REFERENCE SIGNS

[0087] 10 nozzle assembly [0088] 12 first nozzle lip [0089] 14 second nozzle lip [0090] 16 nozzle discharge slot [0091] 20 adjusting element [0092] 30 thermoelement [0093] 40 casting roll [0094] 50 melt [0095] 60 clamping blade [0096] 70 thickening [0097] 72 thin section