Film machine for the production of stretch film

Abstract

A film machine (10) for the production of stretch film, comprising a discharge device (20) with a discharge gap (22) for the discharge of flowable film material (100) and a rotatably mounted casting roller (30) for receiving the discharged flowable film material (100) on the surface (32) of the casting roller (30), further comprising a cleaning device (40) with a rotatably mounted cleaning roller (42) for contacting the film material (100) arranged on the surface (32) of the casting roller (30), characterized in that the cleaning device (40) has an adjustment mechanism (50) with a circumferential adjustment (52) for adjusting a cleaning position (PP) of the cleaning roller (42) along the circumferential direction of the casting roller (30), wherein a tear-off roller (60) is provided around which the film material (100), which has solidified into a film web (110), is lifted from the surface (32) of the casting roller (30) runs,wherein the adjustment mechanism (50) has a radial adjustment (54) for adjusting the radial position of the cleaning roller (42) to change the distance and / or the contact force of the cleaning roller (42) to the surface (32) of the casting roller (30), wherein the circumferential adjustment (52) and the radial adjustment (54) are designed separately from each other.

Description

[0001] The invention relates to a film machine and a method for adjusting a cleaning position of a cleaning roller of a film machine.

[0002] It is known that film machines are used to produce stretch film. These machines are typically equipped with an outlet device that directs liquid film material supplied by an extruder through an outlet gap onto a casting roller. This casting roller usually rotates and is designed to be cooled. During rotation, the liquid film material cools below its melting point. As it solidifies, the film material forms a web that can be lifted from the casting roller and conveyed further. Sufficient cooling is crucial to ensure that the liquid or flowable film material solidifies into a solid film web before it is lifted. During the cooling process, components of the liquid film material may outgas and condense on the surface of the casting roller.Condensation builds up between the film material and the surface of the casting roller. Over a longer production process, this contamination can accumulate, leading to high reject rates or even tearing within the film machine. Therefore, cleaning devices with cleaning rollers are known to clean the film material in the area of ​​the frost line, which represents the transition between the flowable and solid film material. The cleaning function is performed by pressing the cleaning roller against the surface of the casting roller, thereby lifting and removing the condensation droplets and other contaminants along with the film web.

[0003] A disadvantage of conventional film stretching machines is that the cleaning roller has a fixed position. This fixed position limits the machine's line speed. For stretch films, the degree of elasticity is particularly important for the film's quality and price. High elasticity is achieved primarily through high melting temperatures of the film material and slow cooling rates. However, the fixed position of the cleaning roller and the necessary correlation between its position and the frost line prevent any variation in the contact length on the casting roller. Therefore, either maximum elasticity can be achieved for the stretch film, or, with slow cooling rates and / or high melting temperatures, a correspondingly slow line speed must be used on the film stretching machine.

[0004] Machines for the production of films are also known from documents US 4 627 804 A, DE 14 79 904 A, US 3 159 696 A, US 3 374 303 A and WO 2014 / 156 807 A1.

[0005] The object of the present invention is to at least partially overcome the disadvantages described above. In particular, it is the object of the present invention to increase the line speed of the film machine in a cost-effective and simple manner.

[0006] The foregoing problem is solved by a film machine with the features of claim 1 and a method with the features of claim 9. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the film machine according to the invention naturally also apply in connection with the method according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always refers, or can refer, to each other.

[0007] A film machine according to the invention is used for the production of stretch film. For this purpose, an outlet device with an outlet gap is provided for the discharge of flowable film material onto a rotatably mounted casting roller. The discharged flowable film material is collected on the surface of the casting roller. Furthermore, a cleaning device is provided, with a rotatably mounted cleaning roller for contacting the film material arranged on the surface of the casting roller. A film machine according to the invention is characterized in that the cleaning device has an adjustment mechanism with circumferential adjustment for adjusting the cleaning position of the cleaning roller along the circumferential direction of the casting roller.

[0008] A film machine according to the invention is therefore fundamentally based on known film machines and, in particular, includes a cleaning device. The function of the cleaning roller is to be carried out in a known manner, such that contact and pressure of the flowable film material, which is arranged on the surface of the casting roller, leads to the embedding of contaminants between the film material and the surface of the casting roller. This allows a particularly temporary bond to form between the contaminant and the film material, which results in the contamination being carried away when the film web is lifted.

[0009] To ensure the aforementioned cleaning function, it is crucial that the cleaning device, and thus also the cleaning roller, is in a defined cleaning position. This cleaning position must be located, in particular, in an area where the frost line of the film material is also situated. For the purposes of this invention, a frost line is understood to be the point or line, especially the area along the circumferential direction of the casting roller, where the transition between the flowable film material and the solid film material takes place. Since a film machine is typically a continuous production process, a quasi-stationary state will be established, leading to a defined point or circumferential line on the casting roller where the frost line is located.

[0010] In the area of ​​the frost line, the foil material is now hard enough to absorb the necessary force through contact with the cleaning roller. At the same time, the fluid foil material in the frost line area is still soft enough to allow the contaminants to be pressed into and carried away from the inside surface of the casting roller.

[0011] The adjustment mechanism provided according to the invention now allows for significantly increased flexibility of the plastering device. The plastering roller can be adjusted, particularly within defined limits or between defined end stops. This adjustment occurs along the circumferential direction of the casting roller, i.e., in the direction of rotation or against the direction of rotation of the casting roller. Because the discharge gap and the lifting position are typically defined, for example by means of a tear-off roller, the adjustment of the plastering roller can now follow a variation of the frost line. If, for example, a change of material occurs in the film machine, there is often also a change in the melting temperature. This, in turn, leads to a change in the positioning of the frost line if the line speed remains constant.Whereas previously known film machines required the line speed to be reduced at high melting temperatures in order to adjust the constant contact length so that the frost line aligned with the fixed position of the cleaning roller, the invention now allows for flexible adjustment of the cleaning roller's position. In particular, this enables maximum utilization of the available contact area on the casting roller. Thus, even at high melting temperatures, a maximum backward movement of the cleaning roller allows for a slow cooling rate and correspondingly slow cooling functionality of the casting roller.

[0012] In a cleaning roller according to the invention, this can of course be adapted to the cleaning function. For example, rubberized surfaces are conceivable to achieve an improved cleaning effect. Spiral grooves are also possible to improve the removal of air bubbles from the film or from the cleaning roller.

[0013] In addition to the high stretchability that can now be achieved in this way, the line speed and thus the time-related production capacity of such a film machine can also be significantly increased.

[0014] It is advantageous that, in a film machine according to the invention, the adjustment mechanism includes a radial adjustment for changing the radial position of the cleaning roller, thus altering the distance and / or the contact pressure of the cleaning roller to the surface of the casting roller. The radial adjustment is therefore an additional adjustment option to the circumferential adjustment. The circumferential adjustment and the radial adjustment are designed separately and, in particular, independently of each other. This means that both adjustment directions, i.e., radial and circumferential, can be performed independently of each other. This allows for different control scenarios according to the invention. For example, the cleaning roller can be lifted during the search for or approach to the cleaning position to prevent potential damage to the film web and / or the cleaning roller.Furthermore, it is possible that adjustment via the radial movement of the cleaning roller only occurs after the cleaning position has been reached. This reduces the gap between the surface of the cleaning roller and the surface of the casting roller, which can also be referred to as the cleaning gap. Besides a quantitatively large adjustment between a large cleaning gap, for example, for threading the film web, and a small cleaning gap, a quantitatively small adjustment is also conceivable. For example, radial adjustments in the range of a few micrometers, particularly in the range between 10 µm and 100 µm, can lead to the adaptation to a load situation, as described later. This radial adjustment can also be driven in this way, for example, hydraulically, pneumatically, and / or by a motor.

[0015] It is also advantageous that a tear-off roller is provided in a film machine according to the invention, around which the film material, solidified into a film web, runs when lifted from the surface of the casting roller. The lift-off point, defined by the position of the tear-off roller, and the receiving point, defined by the position of the discharge gap, generate a wrap angle of the casting roller in the range of approximately 260° to approximately 330°. These are, of course, degrees. A range between approximately 270° and approximately 320° is preferred. A range between approximately 290° and approximately 305° is particularly preferred. The larger this wrap angle, the greater the contact length. This allows for correspondingly slower cooling rates, higher cooling capacities, and / or higher line speeds. It should be noted that one parameter in particular always needs to be optimized.For example, the greater contact length can be used to provide a higher cooling capacity. It can also be used to achieve higher line speeds despite slower cooling rates. The described wrap angles are particularly suitable for casting rollers with diameters in the range of approximately 1,000 mm and 1,500 mm. Casting rollers with diameters in the range of approximately 1,200 mm to approximately 1,400 mm are preferred.

[0016] A further advantage is that, in a film machine according to the invention, the circumferential adjustment of the adjustment mechanism is designed for at least partially stepless adjustment of the cleaning roller's position in the circumferential direction of the casting roller. In particular, completely stepless adjustment of the cleaning roller's position is advantageous. For example, guide gears, guide rails, or guide elements can be provided which, for example, by means of clamping devices or other fixing means, can be continuously attached, fixed, or clamped in any circumferential position. It is preferred if this at least partially stepless adjustment of the cleaning roller is possible, particularly in the absolute angle range between 115° and approximately 285° of the casting roller.Particularly in the rear section of the casting roller, i.e., at high angles, a very fine, stepless adjustment may be preferable to allow for especially precise alignment with the exact position of the frost line on the film material. A chain drive, for example, can be used for circumferential adjustment.

[0017] Furthermore, it is advantageous if, in a film machine according to the invention, the circumferential adjustment of the adjustment mechanism is designed to allow movement of the cleaning roller in the circumferential direction of the casting roller into a maintenance position, particularly outside the frame of the film machine. In addition to the primary function according to the present invention, which is to enable flexible adjustment of the cleaning position to the frost line, the maintenance required in addition to operation can also be simplified according to the invention. Thus, the range of motion can be extended, particularly with regard to at least one additional end position for the cleaning roller or the cleaning device and the adjustment mechanism. According to this embodiment, it is now possible to move the cleaning roller into a maintenance position in which individual components or the entire cleaning roller are particularly easily accessible.This can lead to the cleaning roller being moved out of the way to access other components of the film machine. More importantly, however, this allows the cleaning roller itself to be moved into a more easily accessible position. This is particularly advantageous for maintenance or cleaning work, for example, after a film tear has occurred in the film machine. The frame serves primarily to absorb the resulting bearing forces. Such a frame can also be designed as a housing.

[0018] A further advantage can be achieved if, in a film machine according to the invention, the adjustment mechanism, in particular a radial adjustment of the adjustment mechanism, has a sensor device for detecting at least one of the following load parameters of the plaster roller for load compensation. The sensor device is adapted to the respective type of load parameter. - Dead weight - Angle between the weight vector of the cleaning roller and the casting roller - Circumferential position of the cleaning roller in relation to the casting roller - axial deflection of the plaster roller - axial contact pattern and / or contact force of the cleaning roller on the casting roller

[0019] The preceding list is not exhaustive. This sensor device can be used, in particular, to provide dead weight compensation. For this purpose, the film machine is preferably equipped with a control unit for receiving and processing sensor signals from the sensor device. The dead weight is understood in terms of its varying effects on the contact situation. For example, when positioned above the center of gravity, and thus with a force vector that is at least acutely perpendicular to the surface of the casting roller, dead weight support can be assumed. In other words, the resulting contact force between the cleaning roller and the film material is supported by the dead weight.If the cleaning roller is located below the center of gravity of the casting roller, the force vector will point away from the surface of the casting roller, so that the cleaning roller's own weight counteracts the contact force. According to the invention, weight compensation is thus possible by detecting the cleaning roller's own weight, its weight vector, or indirectly by determining its circumferential position. Similar compensation can also be achieved with regard to the axial deflection of the cleaning roller, for example, by means of sensor devices in the form of strain gauges. A corresponding change in the axial contact pattern and / or the pressure force can also be compensated for in this way.

[0020] It is further advantageous if, in a film machine according to the invention, the cleaning device has at least one separate drive on each side of the cleaning roller for a rotational drive of the cleaning roller. These are, in particular, drive motors. The drives are synchronized with each other, especially via a control unit, so that a synchronous drive with respect to the rotational speed between the casting roller and the cleaning roller can be achieved. This also significantly improves the parallelism of the described cleaning roller and the casting roller. Undesired torsion caused by corresponding counter-forces or asynchronous drive situations for the cleaning roller is also effectively prevented in this way. Alternatively, a passive drive via friction with the casting roller and / or the film material for the cleaning roller can also be achieved. Mechanical synchronization is also conceivable within the scope of the present invention.

[0021] It is further advantageous if, in a film machine according to the invention, the cleaning roller is pivoted about an adjustment axis by means of the circumferential adjustment. This adjustment axis is aligned parallel, and in particular coaxially, with the rotation axis of the casting roller. The adjustment axis is thus the pivot axis around which the pivoting movement of the cleaning roller is performed. If this axis is aligned, in particular coaxially, with the rotation axis of the casting roller, then the cleaning roller also pivots accordingly about the rotation axis of the casting roller. The distance between the cleaning roller and the casting roller therefore remains identical, meaning that the cleaning gap defined in this way also does not change during the pivoting movement of the cleaning roller. This offers significant advantages, especially in a simple embodiment of the adjustment mechanism without radial adjustment.When circumferential adjustment and radial adjustment are combined, this leads to a clear separation of the two adjustment directions and thus to easier control or regulation.

[0022] A further advantage can be achieved if a detection device for identifying a frost line in the solidifying film material is provided in a film machine according to the invention. In particular, the adjustment mechanism incorporates this detection device. For example, automatic or assisted manual detection of the frost line can be performed in this way. For example, an automated temperature sensor or an infrared sensor is able to determine the frost line as precisely as possible in correlation with stored temperature conditions of the film material. A camera can be used for visual inspection by the operator, which also assists in the detection of the frost line. This allows the method described later to be carried out, particularly in an automated manner, to adjust the correct position with the desired reference to the frost line.

[0023] Also part of the present invention is a method for adjusting a cleaning position of a cleaning roller of a film machine, in particular according to the present invention, comprising the following steps: - Capturing a frost line of solidifying film material on the surface of a casting roller of the film machine, - Moving the plastering roller by means of a circumferential adjustment of an adjustment mechanism of a plastering device in the circumferential direction of the casting roller to the plastering position at the frost line.

[0024] By using a film machine according to the invention, a method according to the invention offers the same advantages as those explained in detail with reference to a film machine according to the invention. The detection of the frost line and the corresponding movement can be carried out either automatically, for example by means of sensor detection, or manually by visual inspection or camera monitoring.

[0025] A method according to the invention can be further developed in such a way that the frost line is detected by means of a detection device, in particular continuously, in order to control and / or regulate the movement of the plaster roller to the plastering position at the frost line. A control device can thus be equipped with corresponding sensor signals from the detection device in order to subsequently control and / or regulate the movement of the plaster roller. For example, an automatic adjustment at the beginning of production is conceivable. Furthermore, continuous detection allows for readjustment, so that even with fluctuations in production quality and the associated variation in the location of the frost line, the plastering functionality is provided with high plaster quality according to the invention.

[0026] It is also advantageous if, in a method according to the invention, the plastering position of the plaster roller is assumed within a range of ±5°, particularly 0° to 5°, around the detected frost line, and particularly within a range of ±2°, preferably between 0° and 2°, around the detected frost line. These degree values ​​are degrees of angle around the frost line. The more precisely the plastering position is assumed, the more precise and higher the plastering function and plaster quality will be. However, specifying a corresponding tolerance range allows both the necessary detection device and the accuracy of the movement of the adjustment mechanism to be equipped with simpler control and simpler mechanics.

[0027] It is also advantageous if, in a method according to the invention, at least one load parameter of the plaster roller is detected, and a load compensation for the plaster roller is carried out based on the detected load parameter. This includes, in particular, compensation for the roller's own weight, compensation for deflection, and / or compensation for contact force, as have already been explained several times.

[0028] Further features, advantages, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. The drawings schematically show: Fig. 1 a first embodiment of a film machine according to the invention, Fig. 2 the embodiment of the Fig. 1. When searching for the frost line, Fig. 3 the embodiment of the Fig. 1 to 2 with the cleaning device in cleaning position, Fig. 4 the embodiment of the Fig. 1 to 3 with the cleaning device in a parked position, Fig. 5 the embodiment of the Fig. 1 to 4 with the cleaning device in a maintenance position, Fig. 6 a top view of a film machine with the cleaning roller in a first position and Fig. 7 the representation of the Fig. 6 with a cleaning roller in the second position.

[0029] The Fig. Figures 1 to 5 show an embodiment of a film machine 10 according to the invention. The main components of the film machine 10 are arranged and, in particular, mounted rigidly or movably within a frame 12, which can also be designed as a housing. Flowable film material 100 is applied via an outlet gap 22, starting from an outlet device 20. This is done, for example, by upstream extruder devices that melt corresponding plastic granules and deposit them through the outlet gap 22 onto the surface 32 of the casting roller 30.

[0030] The casting roller 30 rotates counterclockwise and has a cooled surface 32. This causes the film material 100 to solidify during rotation until a certain point in time when the flowable film material 100 has solidified into a film web 110. The location of this solidification is called the frost line FL in Fig. 1 shown.

[0031] Again Fig. As can also be seen from Figure 1, a lift-off point 64 for the film web 110 is defined by the arrangement of a corresponding tear-off roller 60. Together with the receiving point 24, this forms a wrap angle α, which here is approximately 300° of the casting roller 30. This results in a correspondingly long contact length, so that in this way, according to Fig. 1. A reduction in the cooling rate would be possible, resulting in slower cooling and a frost line FL shifted counterclockwise in the circumferential direction. With a constant rotational speed and thus a constant line speed, a stretch film with higher elasticity could be produced in this way.

[0032] If the production process is now carried out or continued, the cleaning position PP of a cleaning device 40 can be adjusted once or continuously, as described below. Starting from Fig. 1. A detection device 70 is used to detect the frost line FL. This can be, for example, a camera, an infrared sensor, and / or a temperature sensor. An adjustment mechanism 50 is equipped with a circumferential adjustment 52, which also includes the detection device 70. A circumferential adjustment is thus carried out up to a location according to Fig. 2. Here, the detection device 70 detects the frost line FL. By retracing its steps clockwise along the circumferential direction of the casting roller 30, the cleaning position PP of the cleaning roller 42 is set according to Fig. Position 3 is assumed. In this position, a radial adjustment 54 is still negligible. The preceding steps, the acquisition of the sensor data and the corresponding control or regulation of the adjustment mechanism 50, are carried out by the control unit 14 shown, which is connected to the corresponding components via signal communication. In addition, a sensor device 56 can provide the sensor technology, which will be explained later, for a necessary or desired compensation of the dead weight, the contact pressure, or similar load parameters.

[0033] For the end of production or for threading a film web 110 at the beginning of production, a parking position can be used according to Fig. 4 of the plastering device 40. In addition to the adjustment using the circumferential adjustment 52, the plastering roller 42 is offset radially outwards using the radial adjustment 54, so that the resulting plaster gap has been significantly increased. Threading is thus made easier.

[0034] If the film web 110 tears within the film machine 10, or if maintenance work is necessary in the film machine 10 within the frame 12 or on the cleaning device 40, the entire adjustment mechanism 50 can move the cleaning device 40 into a maintenance position WP, as described by the Fig. Figure 5 shows. Here, the cleaning roller 42 and, in particular, the entire adjustment mechanism 50 as well as a large part of the cleaning device 40 are located outside the frame 12.

[0035] The Fig. 6 and Fig. Figure 7 shows one way to compensate for different load parameters of the plastering roller 42. It can be seen that when the plastering roller 42 is positioned below the casting roller 30, both a corresponding deflection (see dotted lines) and a downward-directed force vector reduce the contact force between the plastering roller 42 and the casting roller 30. Adjusting the roller upwards to reduce the plastering gap can compensate for this effect. Conversely, the situation is as follows: Fig. 7 is formed by the fact that the described deflection of the cleaning roller 42 and its own weight support the contact effect and thus the pressure force on the casting roller 30. To compensate for this operating situation, a radial adjustment 54 would increase this cleaning gap and / or the pressure force again, thus creating the compensation effect. As the Fig. 6 and Fig. Figure 7 further shows that the corresponding axes, namely the adjustment axis VA of the adjustment mechanism 50 and the rotation axis RA of the casting roller 30, are aligned parallel and coaxially. The rotation axis RA of the cleaning roller 42 is aligned parallel to the rotation axis RA of the casting roller 30. Finally, there are two separate drives 44 in the form of electric motors on both sides of the cleaning roller 42, and these drives 44 are synchronized with each other. Synchronization can be ensured, for example, by the control unit 14 already described.

[0036] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention. Reference symbol list 10 film machine 12 frame 14 Control unit 20 Outlet device 22 Outlet gap 24 Recording location 30 Casting roller 32 surface 40 Cleaning device 42 Cleaning roller 44 Drive 50 adjustment mechanism 52 Circumference adjustment 54 Radial adjustment 56 Sensor device 60 demolition roller 64 Departure point 70 Detection device 100 sheets of foil material 110 foil strips α Wrap angle PP cleaning position WP Maintenance Position VA adjustable axle RA axis of rotation FL Frost line

Claims

[1] Film machine (10) for the production of stretch film, comprising an outlet device (20) with an outlet gap (22) for the outlet of flowable film material (100) and a rotatably mounted casting roller (30) for receiving the discharged flowable film material (100) on the surface (32) of the casting roller (30), further comprising a cleaning device (40) with a rotatably mounted cleaning roller (42) for contacting the film material (100) arranged on the surface (32) of the casting roller (30), characterized byin that the cleaning device (40) has an adjusting mechanism (50) with a circumferential adjustment (52) for adjusting a cleaning position (PP) of the cleaning roller (42) along the circumferential direction of the casting roller (30), wherein a tear-off roller (60) is provided, around which the film material (100) solidified into a film web (110) runs when lifted off from the surface (32) of the casting roller (30), wherein the adjusting mechanism (50) has a radial adjustment (54) for adjusting the radial position of the cleaning roller (42) for changing the distance and / or the pressing force of the cleaning roller (42) to the surface (32) of the casting roller (30), wherein the circumferential adjustment (52) and the radial adjustment (54) are designed separately from one another. [2] Film machine (10) according to claim 1, characterized bythat a lifting location (64) defined by the position of the tear-off roller (60) and a receiving location (24) defined by the position of the outlet gap (22) produce a wrap angle (α) of the casting roller (30) in the range between approximately 260° and approximately 330°. [3] Film machine (10) according to one of the preceding claims, characterized by that the circumferential adjustment (52) of the adjustment mechanism (50) is designed for an at least partially continuous adjustment of the cleaning position (PP) of the cleaning roller (42) in the circumferential direction of the casting roller (30). [4] Film machine (10) according to one of the preceding claims, characterized by that the circumferential adjustment (52) of the adjustment mechanism (50) is designed for a movement of the cleaning roller (42) in the circumferential direction of the casting roller (30) into a maintenance position (WP), in particular outside a frame (12) of the film machine (10). [5] Film machine (10) according to one of the preceding claims, characterized bythat the adjustment mechanism (50), in particular a radial adjustment (54) of the adjustment mechanism (50), has a sensor device (56) for detecting at least one of the following load parameters of the cleaning roller (42) for load compensation: - Dead weight - Angle between the dead weight vector of the cleaning roller (42) and the casting roller (30) - Circumferential position of the cleaning roller (42) relative to the casting roller (30) - Axial deflection of the cleaning roller (42) - Axial contact pattern and / or contact force of the cleaning roller (42) on the casting roller (30) [6] Film machine (10) according to one of the preceding claims, characterized by that the cleaning device (40) has at least one separate drive (44) on each side of the cleaning roller (42) for a rotation drive of the cleaning roller (42). [7] Film machine (10) according to one of the preceding claims, characterized bythat the cleaning roller (42) is pivoted by the circumferential adjustment (52) about an adjustment axis (VA) which is aligned parallel, in particular coaxially, with the rotation axis (RA) of the casting roller (30). [8] Film machine (10) according to one of the preceding claims, characterized by that a detection device (70) is provided for detecting a frost line (FL) of the solidifying film material (100), in particular the adjusting mechanism (50) has this detection device (70). [9] Method for adjusting a cleaning position (PP) of a cleaning roller (42) of a film machine (10), in particular with the features of one of claims 1 to 8, comprising the following steps: - detecting a frost line (FL) of solidifying film material (100) on the surface (32) of a casting roller (30) of the film machine (10), - Moving the cleaning roller (42) by means of a circumferential adjustment (52) of an adjustment mechanism (50) of a cleaning device (40) in the circumferential direction of the casting roller (30) to the cleaning position (PP) at the frost line (FL), wherein an adjustment of the radial position of the cleaning roller (42) takes place to change the distance and / or the pressure force of the cleaning roller (42) to the surface (32) of the casting roller (30), wherein the movement in the circumferential direction and the adjustment of the radial position take place separately from one another. [10] Method according to claim 9, characterized by that the frost line (FL) is detected by means of a detection device (70), in particular in a continuous manner, in order to carry out the movement of the cleaning roller (42) to the cleaning position (PP) at the frost line (FL) in a controlled and / or regulated manner. [11] Method according to one of claims 9 or 10, characterized bythat the cleaning position (PP) is taken by the cleaning roller (42) in the range of +-5° around the detected frost line (FL), in particular in the range of +-2° around the detected frost line (FL). [12] Method according to one of claims 9 to 11, characterized by that at least one load parameter of the cleaning roller (42) is detected, wherein a load compensation for the cleaning roller (42) is carried out on the basis of the detected load parameter.

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