Method for producing film from a total amount of raw materials using a film extrusion machine, and computer program product for carrying out the method

Description

[0001] The invention relates to methods for producing film from a total amount of raw materials using a film extrusion machine according to the preamble of claim 1. Furthermore, the invention relates to a corresponding computer program product.

[0002] It is well known that in order to produce film with desired properties, film extrusion lines must be adjusted with regard to their production parameters. A multitude of production parameters must be taken into account. Temperatures, pressures, or other physical variables that directly affect the raw materials, intermediate products, and / or the finished film must be adjusted at many points. This applies particularly to the adjustment, i.e., the control and / or regulation of the film extrusion line.

[0003] The resulting film can then be characterized with regard to its properties, particularly in the laboratory, but also during production. In particular, the actual performance of the film's function is examined, as well as measurable film parameters such as tear strength or stretchability.

[0004] Known solutions for controlling and / or regulating film extrusion systems are largely based on the experience and knowledge of the operating personnel.

[0005] The same applies to the selection of raw materials. Here, too, the raw materials are selected based on experience, testing, and the manufacturers' information on the raw materials.

[0006] For example, DE 10 2019 127 549 A1 discloses a method that involves selecting a film extrusion line, as well as entering the parameters and settings relating to the film extrusion line, the desired properties of the film to be produced, and the raw materials used for production into a production model. Here, too, however, the selection of the raw materials to be used in production is largely based on the experience of the respective operator or on the basis of tests and the manufacturer's specifications for the respective raw materials.

[0007] Overall, the production of a film with the desired properties can require lengthy preparatory work, which can also be expensive.

[0008] The object of the present invention is to at least partially remedy the disadvantages described above. In particular, the object of the present invention is to produce a film with the desired properties more cost-effectively and simply.

[0009] The above object is achieved by a method having the features of claim 1 and a computer program product having the features of claim 10. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the computer program product according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0010] The process according to the invention relates to the production of film from a total amount of raw materials using a film extrusion machine. The process comprises the following steps: Recording machine parameters for properties and / or settings of at least one film extrusion machine, recording film parameters for desired properties of the film, recording raw material parameters for properties of the raw materials, entering the recorded parameters into a film production model.

[0011] According to the invention, the method also comprises the steps: Calculation of a selection and / or quantity of raw materials from the total quantity of raw materials based on the recorded parameters and the film production model, indication of the selection and / or quantity of raw materials.

[0012] The method according to the invention thus serves to specify, for a desired film, which partial quantity of raw materials and / or which mass of raw materials is to be selected from the total quantity of raw materials available. The method according to the invention specifies this selection and / or the quantity. In the context of the invention, "total quantity" refers to the different raw material types, whereas the term "mass" or "quantity" reflects the volume and / or weight of the selected raw material.

[0013] Film extrusion machines can be used to describe all extrusion machines, as well as downstream components, that convert raw materials into film, as well as downstream machine components such as stretching devices and winding devices, in which the film is first wound for transport. An extrusion machine can operate according to the principle of a blown film line or a flat film line.

[0014] "Capturing" encompasses various types of data capture. For example, immutable parameters can be recorded once in a database. This is the case, for example, when they concern the geometric properties of the film extrusion machine. Other parameters can be changed at intervals, such as information about the available raw materials. Still other parameters can be recorded on a job-specific basis, such as the desired properties of the film. Accordingly, capture can also be based on different characteristics. For example, the parameters can be made available via databases, which are stored, for example, in the memory of the film extrusion machines or decentrally in internet portals. In this case, capture would be referred to as "reading data." For example, job-specific parameters can be captured via input devices, such as a keyboard.

[0015] Within the scope of the method according to the invention, it is necessary to record machine parameters and / or settings for at least one film extrusion machine. The recording of machine parameters can take place in particular during commissioning, during which, for example, geometric data of the film extrusion machine is stored in a database. This geometric data includes, in particular, the maximum number of layers of the film, the maximum number of individual raw materials that can be used for a single layer, the design of extruder screws for melting the raw materials, the width or circumference of the die lip, and the thickness of the die lip. This list is not exhaustive and therefore does not limit the invention.

[0016] Recording settings refers to machine components that can be controlled with respect to geometric properties such as position or physical variables such as temperature, volume flow, or speed. Since these settings are variable and can also be adjusted during film production, recording settings can refer to a range of values ​​rather than just a single setting.

[0017] The recording of raw material parameters refers to the properties of raw materials, such as their composition and information on their manufacturing parameters, as well as the grain size of the granules of these raw materials. Raw material parameters can also include economic data, such as price or availability at a specific point in time.

[0018] According to the invention, all of the recorded parameters are made available to a film production model in a subsequent step. One of the core ideas is that the film production model then selects a selection and / or a quantity of raw materials from the totality of available raw materials based on the recorded parameters. It is therefore no longer necessary, as in the prior art, to manually determine the appropriate raw materials for the desired properties of the film and to procure them in the required quantity and then to adjust the film extrusion machine so that the desired film is produced from the procured raw materials. Rather, the method according to the invention uses the recorded parameters within the film production model in relation to one another and determines the suitable raw materials that lead to the desired film. Additionally or alternatively, the required quantity of raw materials is also calculated.The latter is particularly the case when the selection or subset of raw materials, i.e., their number, corresponds to the total quantity of raw materials. In the context of the invention, the term "total quantity" refers to the total number of different raw materials and not their physical parameters such as weight, volume, or density.

[0019] As a subsequent step of the method according to the invention, information on the selection and / or quantity of raw materials is now output. This output can, for example, be on a screen so that an employee of a film producer can further process this information. However, this information can also be output directly or indirectly to an interface so that further electronic processing is enabled. For example, it is conceivable that the information is output to a digital ordering system for the raw materials so that the required raw materials for film production can be ordered particularly quickly. However, the information can also be output directly to a previously specified film extrusion machine so that it can independently procure the raw materials from raw material supply facilities, in particular silos, for example via an automatic system.It is also conceivable to output the information to a warehouse, where an employee can then pick the required raw materials in the required quantities.

[0020] It can be further advantageous to provide a recommendation as to which film extrusion machine should be selected to produce the desired film if several film extrusion machines, in particular different film extrusion machines, are available for producing the film. Often, a manufacturing plant has several film extrusion lines available that differ from one another in their designs with regard to geometric data as well as their physical parameters. In such a situation, it is possible to select one of these lines based on the film production model. For example, if the desired film has a five-layer structure, it may be advantageous if the product is produced on a film extrusion line for films with a maximum of seven layers.

[0021] The method according to the invention can also include a step in which, depending on the raw materials, a prediction of the maximum possible output of the film extrusion machine, in particular of the selected film extrusion machine, is made. The maximum possible output depends not only on machine parameters, but above all on the raw materials used. Based on this information, even the actual machine settings used can be adjusted. The advantage of this approach is that the machine time required to produce the film is reduced, thus reducing the cost share of machine time in the final product.

[0022] Furthermore, it can be advantageous if the method according to the invention comprises a step in which the expected properties of the film are calculated based on the film production model. It may be possible that the film does not fully exhibit the desired properties, but there are minor deviations, for example if a required raw material cannot be processed according to the specifications. However, in this case, the properties of the film can be adjusted and the actual properties can subsequently be communicated so that they can be taken into account in subsequent film processing. In addition, the desired properties and the expected properties can be verified through subsequent tests. This enables the film production model to be adapted.

[0023] It may even be possible that the desired film properties cannot be achieved, but deviate from individual properties. This can be the case, for example, if a raw material is required but is not available within the total quantity of raw materials. In this case, the film production model can suggest or select an alternative raw material. In another case, raw materials may be specified, one of which cannot be processed as required in the film extrusion machine. In such a case, the deviation from the desired film properties to the anticipated film properties can be evaluated, and a decision can be made by the film producer.

[0024] It can be helpful if the method according to the invention includes a step in which tolerance limits are recorded with regard to at least one property of the film. This makes it possible to provide multiple pieces of information regarding the selection and / or quantity of raw materials. It is advantageous if, in addition, a comparison is made between a property of the desired film and the same property of the anticipated film. The properties can be prioritized. This can make it possible for a certain, irrelevant property to be tolerable within a wider range, while conversely, the tolerance limits for a relevant property, such as the extensibility of the film, can be set more narrowly.

[0025] Further advantages emerge when the inventive method is supplemented by the following step: taking previous orders into account when calculating the selection and / or quantities of raw materials. Taking previous orders into account can, for example, be used to modify relationships between parameters prior to the calculation, thus achieving greater accuracy in the calculation results. Overall, this measure leads to an improvement in the film production model. This can ultimately result in a film that even better fulfills the desired properties.

[0026] It is also advantageous if the method according to the invention is supplemented by the steps of recording batch-specific properties of at least some of the raw materials and taking these batch-specific properties into account. As a rule, nominally identical raw materials differ in their properties if they are produced at different times and, in particular, not continuously. Reproduction of the same raw material often takes place under slightly different conditions. For example, such information on the production conditions of the corresponding batch can be recorded within the framework of the method according to the invention. Taking this information, and thus the batch-specific properties, into account fulfills the object of the present invention even better.

[0027] In order to further improve the method according to the invention in an advantageous manner, the following steps can be added: Recording at least one property of the film Calculating the deviation of this property from the property of the expected property of the film Deriving at least one property of a raw material

[0028] The properties of the film can be determined in a downstream test inline or offline through direct or indirect measurements. These can take place within the film extrusion machine, but also in machines that process the film. However, more precise tests are also conceivable, for example in a laboratory. Quantitative data on these properties is therefore determined, which is then compared with data on the expected properties. At least one property of a raw material can be derived from the calculation. Based on this derivation, raw material parameters can be verified, for example. The verification of the raw material parameters can be used, for example, to identify an error and issue an error message. An error can be caused, for example, if the wrong raw material was provided for the production of the film.

[0029] The present invention also provides a computer program product comprising instructions that, when executed on a computer, cause the computer to perform the steps of a method according to the invention. Thus, a computer program product according to the invention provides the same advantages as those explained in detail with reference to a method according to the invention. Fig. 1Schematic representation of a film extrusion machine, Fig. 2Schematic representation of another film extrusion machine Fig. 3Schematic representation of the sequence of the method according to the invention Fig. 4Schematic representation of the sequence of the method according to the invention with an addition.

[0030] In the Figures 1 and 2Illustrated are exemplary film extrusion machines 10. These film extrusion machines have in common that they are equipped with extruders 20. Each individual extruder supplies the film extrusion machines with molten plastic material for one layer of the subsequent film, which is a plastic film. For this purpose, one or more raw materials R1,... are fed to a first extruder via metering devices 60, and one or more raw materials Rx,... are fed to a second extruder in this manner. The raw materials are generally in the form of plastic granules. The type and / or quantity of the raw materials fed in are predetermined by the method according to the invention.

[0031] The process according to the invention can be carried out using a flat film or a blown film extrusion line according to Figure 2 be carried out. The Figure 1shows a blown film line with the previously described extruders 20. A film web, or film for short 40, is discharged from the nozzle 30. The nozzle 30 is designed as an annular blowing nozzle. The film web is initially formed as a bubble, but is later flattened. This film, which now comprises two individual films lying on top of one another, is wound onto a winding roll 50 via various intermediate elements or, after cutting them apart, onto two winding rolls to the left.

[0032] In the Figure 2 The film extrusion machine is a flat film extrusion machine, which is also equipped here, as an example, with two extruders 20 for different formulations. A film web 40 is output from the nozzle 30, which cools on a cooling roller and is then wound onto a winding roll 50.

[0033] The Figure 3shows a schematic of the sequence of the method according to the invention. A storage and computing device 100 is provided with machine parameters MP relating to properties and / or settings of at least one film extrusion machine, film parameters FP relating to desired properties of the film, and raw material parameters RP n relating to properties of the raw materials. The index n of the raw material parameters RP indicates that this is a totality of raw materials from which one or more raw materials can be selected. The film production model is executed within the storage and computing unit, which model records the aforementioned parameters as inputs and, according to the invention, calculates therefrom which raw materials R m are selected from the totality of raw materials RP n. According to the invention, the required quantity of raw materials R m is also calculated alternatively or simultaneously.The number of selected raw materials is less than or equal to the number of raw materials in the total, i.e. m ≤ n.

[0034] The Figure 4 shows a modified version of the process according to the invention. It is comparable to the schematic representation according to Figure 3 comparable, but the expected properties of the foil FP v are also output. List of reference symbols 10 Film extrusion machine 20 Extruder 30 nozzle 40 film web 50 winding roll 60 Dosing device 100 Storage and computing device R 1,... Raw material Rx,... Raw material MP Machine parameters FP Slide parameters RP n Raw material parameters for the total amount of raw materials R m selected raw materials FPM Film production model

Claims

1. Method for producing a film (40) from a total quantity of raw materials using a film extrusion machine (10), comprising the following steps: - detecting machine parameters (MP) relating to properties and / or settings of at least one film extrusion machine (10) - detecting film parameters (FP) relating to desired properties of the film (40) - detecting raw material parameters (RPn) relating to properties of the raw materials - inputting the detected parameters (RPn) in a film production model (FPM), characterised by the following steps: - calculating a selection and / or a quantity of raw materials (RPm) from the total quantity of raw materials based on the detected parameters and the film production model (FPM) - outputting information relating to the selection and / or the quantity of raw materials (RPm).

2. Method according to claim 1, additionally comprising the following step: specifying a recommendation of a film extrusion machine (10) on which the film (40) is produced.

3. Method according to claim 1, additionally comprising the following step: calculating the expected properties (FPv) of the film (40) based on the film production model (FPM).

4. Method according to any one of the preceding claims, additionally comprising the following step: considering previous orders when calculating the selection and / or quantities of raw materials (RPm).

5. Method according to any one of the preceding claims, additionally comprising the following steps: - detecting batch-specific properties of at least a part of the raw materials (RPn) - considering said batch-specific properties, - calculating a selection and / or quantity of raw materials (RPm).

6. Method according to any one of the preceding claims, additionally comprising the following steps: - detecting at least one property of the film (FP) - calculating the deviation of said property from the expected property of the film (FPv) - inferring at least one property of a raw material.

7. Computer program product comprising instructions which, when the program is executed on a computer, cause the computer to carry out the steps of a method comprising the features of any one of claims 1 to 6.