EP3877144A1

EP3877144A1 - Method for calibrating adjustment means for adjusting a die gap of an outlet die for a film web on a flat film machine

Info

Publication number: EP3877144A1
Application number: EP19798617.7A
Authority: EP
Inventors: Torsten Schmitz; Waldemar COLELL; Bernd-Alexander Groepper
Original assignee: Windmoeller and Hoelscher KG
Current assignee: Windmoeller and Hoelscher KG
Priority date: 2018-11-06
Filing date: 2019-11-05
Publication date: 2021-09-15
Also published as: DE102018127675A1; CN112912227A; WO2020094649A1; US20220111574A1

Abstract

The invention relates to a method and a device for calibrating adjustment means (120) for adjusting a die gap (112) of an outlet die (110) for a film web (FB) on a flat film machine (100), the method having the following steps: • - specifying a calibration position (KP) for the adjustment means (120), • - performing an inspection in order to change the adjustment position (SP) of the adjustment means (120), • - detecting when the calibration position (KP) of the adjustment means (120) has been reached.

Description

Method for a calibration of adjusting means for adjusting a nozzle gap of an outlet nozzle for a film web on a flat film machine

Description

The present invention relates to a method for calibrating adjusting means for adjusting a nozzle gap of an outlet nozzle for a film web on a flat film machine and a control device for carrying out such a method.

It is known that flat film machines are used to provide flat film products. For this purpose, such flat film machines have a large number of extrusion devices which are able to produce a corresponding material composition for different layers of the film product. The melt as a material composition is made from a nozzle gap of an outlet nozzle the flat film machine over the entire width. After the melt has solidified, this film product is in the form of a film web which is cooled on a cooling roll. The film web in the form of the film product can be rolled up on a winding shaft via several subsequent roller systems. In addition, it is also possible to coat or laminate the melt. For example, one or more flat webs can be fed to the melt for this purpose.

To set thickness specifications in the form of a thickness profile, a large number of adjusting means is usually arranged on the outlet nozzle. These can be, for example, so-called thermal bolts, which can provide a defined thermal expansion when subjected to a defined temperature effect, for example as heating output, heating interval, heating voltage or the like. In this way, it is possible to exert a mechanical influence on the nozzle gap and the outlet nozzle, so that the thickness or the thickness of the film web in the outlet of the nozzle gap can be changed.

A disadvantage of the known solutions is that the starting point for regulating the thickness profile is set in a manual manner. The operating personnel of the flat film machine usually set the individual adjusting means manually at the start of production, especially when the machine is stationary. For this purpose, for example, each actuating means can be calibrated or set sequentially with a screwing means. The quality of this calibration is based on the experience of the machine operator. This means that this calibration cannot be reproduced in principle. In order to create an exact and defined starting point, the flat film machine must be brought to a complete standstill. Only then can the operating personnel use a mechanical gauge in the nozzle gap to measure the actual extent, that is to say the actual profile of the nozzle gap, or to adapt it by appropriately varying the adjusting means. In addition to the lack of reproducibility, the procedure described above leads to a very high expenditure of time. If a complete calibration is necessary, the machine must be taken out of operation, which leads to a very high expenditure of time and loss of production. It is an object of the present invention to at least partially remedy the disadvantages described above. In particular, it is an object of the present invention to implement a reproducibility and in particular also a rapid implementation of a calibration on the flat film machine in a cost-effective and simple manner.

The above object is achieved by a method with the features of claim 1 and a control device with the features of claim 10. Further features and details of the invention result from the subclaims, the description and the drawings. Features and details that are described in connection with the method according to the invention apply, of course, also in connection with the control device according to the invention and vice versa, so that with respect to the disclosure of the individual aspects of the invention, reference can always be made to one another.

According to the invention, the method is used to calibrate adjusting means for adjusting a nozzle gap of an outlet nozzle for a film web on a flat film machine. Such a process has the following steps:

- Specifying a calibration position for the actuating means,

- performing a control intervention to change the position of the positioning means,

- Detection of reaching the calibration position of the actuating means.

In contrast to known solutions, an automated or at least partially automated method can now be made available here. This is able to specify a calibration position for one or more actuators as a default value. Then the position is changed by a defined control intervention. In particular, this second step, that is to say the carrying out of the control intervention, is carried out in an automated or partially automated manner. In a first step, it is irrelevant whether the change in the position of the actuating means is detected or not during the control intervention. It is sufficient for the core idea according to the invention if the reaching of the calibration position is monitored. This depends on how the calibration position is specified. If the calibration position is, for example, a defined location, this can be done with the appropriate location sensors Reaching the calibration position can be recognized by the actuator. How, in what direction and, above all, how far the adjusting means is still from the calibration position at the beginning of the method according to the invention is irrelevant for such a procedure. Rather, it is sufficient to set the actuating means in motion by the control intervention, so that the calibration position is correspondingly reached during this movement at a point in time in the future. However, it can be advantageous if in such a simplest embodiment of the method according to the invention the quality, that is to say in particular the direction, of the adjustment of the adjusting means is specified. This can be defined, for example, with a basic quality for all actuators with a common direction as the quality for this movement through the control intervention.

According to the invention it is now possible to move the adjusting means from any actual position into a calibration position in an automated or partially automated manner. This can be done when the machine is at a standstill as well as during ongoing production. As will be explained later, the calibration is preferably carried out in a process step or in a production phase of the flat film machine in which little or no quality production takes place. For example, when switching between different formats, but also during a start-up process or during a commissioning phase, these calibration processes can be carried out.

With a method according to the invention, it is thus possible to carry out the calibration in a reproducible manner. It is therefore possible, by specifying a calibration position, to always set all the adjusting means in the same or essentially the same starting point, so that a standardized one for the subsequent regulation within the production process, for example for adjusting thickness profiles within the production process of the flat film machine Starting point is given. It is thus possible to run the subsequent control procedures in the same way as with known solutions, but to be able to count on improved control results on the basis of a defined and improved starting point.

It can be advantageous if, in a method according to the invention, the same or essentially the same calibration position is specified for at least two adjusting means, in particular for all or essentially all adjusting means. With others Words, all actuating means can be moved into a defined calibration profile, which then forms the starting position for the subsequent control steps. It is a particularly simple solution if all actuating means are moved to the same or essentially the same zero position. This allows the same or essentially the same stroke path to be possible for all adjusting means for the subsequent regulation in the normal production of the flat film machine. A simplified control with improved control results is thereby made even easier and in an improved manner by a method according to the invention.

It can also be advantageous if, in a method according to the invention, an actual position of the actuating means is recorded for consideration when carrying out the control intervention. Such an actual position can be made available, for example, by feedback from corresponding sensors. The actual position can also provide a motion feedback during the movement or movement of the positioning means in order to ensure control during the movement of the positioning means. In this way, the actual position can make a qualitative and / or quantitative statement, in particular if a comparison is made between the actual position and the calibration position. It is thus possible not only to provide the direction in a qualitative manner for the necessary control intervention, but even to provide the quantitatively necessary actuating movement for the respective actuating means through a defined and ascertainable distance between the actual position and the calibration position. An explicit and specific distance between the actual position and the calibration position can be determined, in particular, for the respective adjusting means. This then also allows a specific actuating movement to be applied to each actuating means in a specific manner.

There are also advantages if, in a method according to the invention, the calibration position is specified in the form of a calibration actuating force of the actuating means. In addition to the optical or local sensor detection already explained, it is also conceivable that the specification of the calibration position reflects a force ratio. For example, it is possible to determine the force situation between the respective actuating means and the contacting of the nozzle lip of the outlet nozzle in the form of force monitoring or force sensors. This can be done both in the stationary state of the flat film machine and in the operating state, that is if there is a force equilibrium with the melt in the nozzle exit gap. In In both cases, it is possible to use the calibration actuating force as a calibration position or at least as part of the calibration position. This allows a particularly simple detection of the calibration position and thus also a particularly simple detection of reaching the same.

Further advantages can be achieved if, in a method according to the invention, specific, in particular different, calibration positions are specified for at least two adjusting means. As has already been explained with reference to the detection of the actual position of the actuating means, a different calibration position can specifically ensure an improved overall calibration for each actuating means. In addition to a specific adjustment of two or more adjusting devices, it is also possible to provide different groups of adjusting devices with different calibration positions, but the same for the respective group. For example, edge areas of the film web can be distinguished from a net area which is to be wound up as an actual film product after edge trimming. In this way it is also possible to learn specifically from calibration steps that have already taken place, so that an improved standardization or an improved calibration can be made available for future methods.

There are further advantages if, in a method according to the invention, the control intervention takes place at least partially step by step, in particular in regular steps. A gradual adjustment is therefore carried out until the specified calibration position is reached. It is also possible to combine this gradual adjustment with the open adjustment of the control intervention explained below. A gradual adjustment allows the control to be carried out simply and inexpensively, and at the same time to reduce the force or speed with which the actuating means reaches the desired calibration position to a minimum.

According to a further embodiment of a method according to the invention, it is possible for the control intervention to take place at least partially open until the calibration position is reached. This can also be combined with that from the previous paragraph. For example, the positioning means can be moved quantitatively to the calibration position in large steps. There is no gradual adjustment for the last movement carried out, but rather an open movement slowly to a contact and, for example, until a defined calibration actuating force is reached, the calibration position can be reached. The combination of these two variants enables a defined and sensitive calibration position to be set quickly and easily, yet with a high degree of certainty.

There are also advantages if, in a method according to the invention, the actuating means are at least temporarily fixed in the calibration position reached. Such a temporary fixation allows, in particular as a reversible fixation, to ensure a defined starting point for the subsequent production process of the film web. Such fixations can be provided with the adjusting means themselves, but also with separate fixing means.

Further advantages can be achieved if, in a method according to the invention, the method steps are carried out during the conversion of the flat film machine from a feed product to a follow-up product. The process thus takes place while the flat film machine is in operation. However, the movement can be made available relatively freely during the changeover, so that with this standardization no consideration has to be given to a thickness profile or quality parameters of the film web produced, since the changeover is basically reject material.

The present invention also relates to a control device for calibrating adjusting means for adjusting a nozzle gap of an outlet nozzle for a film web on a flat film machine. Such a control device has a specification module for specifying a calibration position for the actuating means. Furthermore, an intervention module is provided for carrying out a control intervention for changing the setting position of the setting means. In addition, the control device is equipped with a detection module for detecting the reaching of the calibration position of the actuating means. The default module, the intervention module and / or the detection module are preferably designed to carry out a method according to the invention. Further advantages, features and details of the invention emerge 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. They show schematically:

FIG. 1 shows an embodiment of a flat film machine with a control device according to the invention,

FIG. 2 shows the embodiment of FIG. 1 in a schematic side sectional view,

FIG. 3 shows an embodiment of an actuating profile before calibration,

FIG. 4 shows the embodiment of FIG. 3 after calibration,

FIG. 5 shows an embodiment of an actuating profile before calibration,

FIG. 6 shows the embodiment of FIG. 5 after calibration,

Figure 7 shows a possibility of a gradual understanding of the adjusting means and

8 shows a possibility of an open understanding of the standing means.

FIGS. 1 and 2 show a flat film machine 100 in which a nozzle gap 112 of an outlet nozzle 110 is provided over the entire transverse direction QR. The film web FB emerges from this nozzle gap 1 12 along the production direction PR. In order to regulate a thickness profile of this film web FB, a plurality of standing means 120 in the form of thermal bolts is provided here.

FIG. 2 shows the action of the thermal bolts as a standing means 120 from above on the nozzle lip above the nozzle gap 1 12. By applying thermal energy, a thermal expansion of the standing means 120 will reduce the nozzle gap 1 12, so that the thickness or the thickness profile of the Foil sheet accordingly will reduce. FIG. 1 shows the control device 10 on the left-hand side of the flat film machine 100. Here, a calibration position KP can now be specified with the aid of a specification module. Based on this, a corresponding control intervention is prepared in an intervention module 30, so that the reaching of this calibration position KP on the flat film machine 100 can be determined with the aid of the detection module 40.

The calibration process can be carried out, for example, according to FIGS. 3 and 4. A normalized and equivalent alignment of the individual actuating means 120 to one another is shown here in FIG. 4 as the calibration position KP. The movement can now be carried out in a standardized manner from a starting position in the form of the actual position IP of FIG. In this embodiment, the actual position IP and calibration position KP are shown as positioning positions SP of the individual positioning means 120.

Figures 5 and 6 also show a possibility of calibration. Positioning positions SP of the adjusting means 120 are also used here. Here too, the starting point is an actual position IP according to FIG. 5. In contrast to FIGS. 3 and 4, the calibration position KP for each actuating means 120 is not a common calibration position KP, but rather specific ones and different calibration positions KP for each specific actuating means 120.

FIG. 7 shows how the overall movement of the adjusting means 120 can be carried out with a step-wise movement, in this case with three individual movements. At the end of the last step at the right end of FIG. 7, the calibration position KP is reached.

FIG. 8 shows that, regardless of the steps according to FIG. 7, a continuous movement of the adjusting means 120 to the calibration position KP is also possible.

The above explanation of the embodiments describes the present invention exclusively in the context of examples. Of course, if technically meaningful, individual features of the embodiments can be freely combined with one another without departing from the scope of the present invention. Regarding aszei che nl iste

10 control device

20 default module

30 intervention module

40 acquisition module

100 flat film machine

110 outlet nozzle

112 nozzle gap

120 actuators

FB film web

KP calibration position

IP actual position

SP position

QR cross direction

PR production direction

Claims

Patent claims

1. A method for calibrating adjusting means (120) for adjusting a nozzle gap (1 12) of an outlet nozzle (1 10) for a film web (FB) on a flat film machine (100), comprising the following steps:

- Specifying a calibration position (KP) for the actuating means (120),

Performing a control intervention to change the position (SP) of the

Adjusting means (120),

Detecting the reaching of the calibration position (KP) of the adjusting means (120).

2. The method according to claim 1, characterized in that for at least two adjusting means (120), in particular for all or essentially all adjusting means (120), the same or essentially the same calibration position (KP) is specified.

3. The method according to any one of the preceding claims, characterized in that an actual position (IP) of the actuating means (120) is detected for consideration when carrying out the control intervention.

4. The method according to any one of the preceding claims, characterized in that the calibration position (KP) is specified in the form of a calibration actuating force of the actuating means (120).

5. The method according to any one of the preceding claims, characterized in that specific, in particular different calibration positions (KP) are specified for at least two adjusting means (120).

6. The method according to any one of the preceding claims, characterized in that the control intervention takes place at least partially step by step, in particular with regular steps.

7. The method according to any one of the preceding claims, characterized in that the control intervention takes place at least partially open until the calibration position (KP) is reached.

8. The method according to any one of the preceding claims, characterized in that the adjusting means (120) are at least temporarily fixed in the calibration position (KP) reached.

9. The method according to any one of the preceding claims, characterized in that the method steps are carried out during the conversion of the flat film machine (100) from a feed product to a subsequent product.

10. Control device (10) for a calibration of adjusting means (120) for adjusting a nozzle gap (1 12) of an outlet nozzle (1 10) for a film web (FB) on a flat film machine (100), comprising a specification module (20) for a specification a calibration position (KP) for the actuating means (120), an intervention module (30) for carrying out a control intervention for changing the actuating position (SP) of the actuating means (120), further comprising a detection module (40) for detecting the reaching of the Calibration position (KP) of the adjusting means (120).

1 1. Control device (10) according to claim 10, characterized in that the default module (20), the intervention module (30) and / or the detection module (40) are designed for performing a method with the features of one of claims 1 to 9 .