METHOD FOR THE STEP-BY-STEP GUIDANCE OF A MACHINE OPERATOR OF AN EXTRUSION DEVICE WHEN CHANGING FROM A TAPE TO A FOLLOW-UP TAPE

Description

[0001] The present invention relates to a method for the step-by-step guidance of a machine operator of an extrusion device for a film machine when changing from one input recipe to a subsequent recipe.

[0002] It is generally known that different products can be manufactured on film extrusion machines. These products typically differ from one another due to their different formulations. A series of different orders with varying formulations are processed sequentially. The transition between two formulations involves switching from the currently used formulation to the subsequent one.

[0003] As can be seen in the documents DE 10 2013 100812 A1, JP H07 24899 A, EP 1 188 539 A2, EP 0 899 079 A1, DE 10 2004 051196 A1 and DE 10 2013 100866 A1, this change is usually carried out manually in known solutions and based on the experience of the machine operator.

[0004] A disadvantage of the known solutions is that the quality and, above all, the time required to switch from one initial recipe to the next depend solely on the machine operator's knowledge. This can lead to a very high reject rate for this recipe change, especially with inexperienced machine operators. Furthermore, a clear and consistent quality standard for all changes between initial and subsequent recipes cannot be achieved in this way. Finally, the possibility of errors cannot be ruled out.

[0005] The object of the present invention is to at least partially solve the problems described above. In particular, it is an object of the present invention to improve, preferably make safer and / or faster, recipe changes in a cost-effective and simple manner.

[0006] The foregoing problem is solved by a method having the features of claim 1. 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 method according to the main claim naturally also apply in connection with the method according to the dependent claims, and vice versa, so that the disclosure of the individual aspects of the invention is always, or can always be, mutually interdependent.

[0007] According to a method according to the invention for the step-by-step guidance of a machine operator at an extrusion device for a film machine when changing from a feed recipe to a subsequent recipe, the following steps are followed: Detecting a recipe change request, displaying the recipe change request to the machine operator, displaying at least one completion step to be performed for the initial recipe, detecting confirmation from the machine operator for at least one completion step, displaying at least one preparation step to be performed for the subsequent recipe, detecting confirmation from the machine operator for at least one preparation step, completing the change from the initial recipe to the subsequent recipe.

[0008] A method according to the invention is carried out, in particular, in a control unit of an extrusion device. The method according to the invention is triggered by the detection of a recipe change request. This can involve both manual and automatic detection. For example, the machine operator can enter a corresponding recipe change request into a terminal of the extrusion device, so that this manual input is recognized as a recipe change request by the method according to the invention and triggers the subsequent steps.

[0009] The display of recipe change requests can be interpreted both as confirmation of a manually entered recipe change request and as a prompt for the machine operator to perform the subsequent necessary manual steps. This can be done, for example, on a display device of the extrusion machine, in particular a suitable screen.

[0010] According to the invention, at least one completion step for the initial recipe is displayed. Subsequently, confirmation by the machine operator for this completion step is detected. Similarly, the correlation between the display and the detection of confirmation is also established with regard to a corresponding preparation step for the subsequent recipe. A fundamental distinction must be made between the completion processes for the initial recipe and the subsequent processes for the subsequent recipe. The completion steps must be carried out to completely finish the initial recipe. This includes, for example, reducing the fill quantity of the raw materials in various dispensing devices and removing raw materials from such dispensing devices.Cleaning steps within such dispensing devices, in order to remove the last residues of input material of an input formulation from the dispensing devices, can also be understood as a final step within the meaning of the present invention.

[0011] Preparation steps include, in particular, the correlation of the extrusion device with downstream materials of the subsequent formulation. For example, connecting associated conveying equipment to the downstream formulation or feed containers for downstream materials can be considered a preparation step. Modified valve positions, additional cleaning options, or new directions of rotation for metering screws can also be incorporated as preparation steps for a process according to the invention.

[0012] According to the invention, for each step to be performed, i.e., each completion step and each preparation step, a corresponding indicator is provided to the machine operator. This indicator is perceptible to the machine operator, particularly via sensors, and can be, for example, visual or audible. Similarly, the machine operator can confirm the execution or completion of the respective step. Sensors can assist in recognizing the machine operator's confirmation. For example, the machine operator can directly enable confirmation of the completion step by pressing a corresponding button. Alternatively, the confirmation of the completion or preparation step can also be recognized indirectly through a corresponding action by the machine operator, using sensors.

[0013] Once all completion and preparation steps have been both displayed and their execution confirmed, the switch from the initial recipe to the subsequent recipe is completed. This includes both active and passive processes, such as the termination of the associated control procedure of a control unit for the process according to the invention. Only when all specified preparation and completion steps have been finalized and confirmed does the switchover process conclude, allowing the control device to switch to a normal operating mode for the production of the subsequent recipe. This can be done either sensorily or manually by the machine operator.

[0014] For the purposes of the present invention, a film machine is understood to be, in particular, a blown film machine or a so-called cast film machine. Of course, all other embodiments of film machines are also conceivable for a method according to the invention in order to achieve the advantages of the invention.

[0015] The initial recipe is the sum of all input materials currently in production to manufacture a specific product based on that initial recipe. A similar principle applies to the subsequent recipe, where a corresponding product can be manufactured from a variety of subsequent materials. Once the changeover is complete, the subsequent recipe becomes the initial recipe for the next sequential changeover.

[0016] A method according to the invention offers several advantages. In particular, a machine operator with significantly less experience can perform a changeover from one initial recipe to a subsequent recipe with high speed and reliability. Specifically, incorrect strategies or faulty sequences of individual changeover steps within the recipe changeover are avoided, or the risk of such incorrect assignment is significantly reduced. In other words, feedback guidance for the machine operator is provided, ensuring regular interaction between the operator's actions, automatically executed changeover steps, and corresponding feedback confirming the execution of these steps.

[0017] It can be advantageous if, in a method according to the invention, after the machine operator has confirmed the process, at least one automatic step is carried out as part of the changeover from the initial recipe to the subsequent recipe, in particular at least one of the following: Cleaning a suction conveyor, cleaning a feed hopper, cleaning a weighing hopper, cleaning a metering screw, filling a feed hopper with a subsequent material of the subsequent recipe, changing the temperature of an extruder.

[0018] The preceding list is not exhaustive. Naturally, two or more of the steps described above can be performed in parallel or at least overlapping. This allows for even more efficient execution of the process, particularly significantly faster than purely manual methods. The reliability of correct sequential processing is also considerably improved by automating one or more steps. Finally, temporal interfaces can exist between manual and automated steps. For example, a cleaning step can be performed within a defined timeframe, especially in relation to a previously executed finishing or preparatory step. These timeframes can be specified in absolute terms or relative to specific reference points.

[0019] It is also advantageous if, in a method according to the invention, when switching from the initial formulation to the subsequent formulation, each input material of the initial formulation is changed to a subsequent material of the subsequent formulation. In other words, each input material is transformed from an input material into a subsequent material. Each material can also be referred to as a component of the respective formulation. It is particularly important to consider that a change from an input material to a subsequent material can, of course, also mean that the subsequent material corresponds to the input material. Therefore, even a purely percentage-based change in the composition of the formulation changes the input material to the subsequent material according to this definition. Furthermore, it is also conceivable that formulations of varying complexity are used, so that, for example, an empty input material is followed by an actually existing, explicit subsequent material.Conversely, it is also possible that an existing material in this dispensing device is not subsequently used, but rather the material it contains remains in the device or is emptied out. Finally, it should be noted that intermediate materials can, of course, also be used, for example, as a rinsing aid between the use of the initial material and the subsequent material.

[0020] A further advantage arises when, in a method according to the invention, the sequence for processing the changeover of the individual materials is specified as a changeover strategy. A changeover strategy can take a wide variety of aspects into account. Specifying the changeover strategy in conjunction with visual guidance for the machine operator ensures that an optimal, and in particular the best possible, changeover strategy can be pursued essentially independently of the operator's personal experience and knowledge of the specific extrusion device. This not only simplifies the changeover process but, by relieving the operator of the decision regarding the sequence, can also significantly improve the safety and quality of the changeover.

[0021] In a method according to the invention as described in the preceding paragraph, it is advantageous if the switching strategy takes into account at least one of the following switching parameters: Stability of the extruded product, in particular a film bubble; temperature profile of an extruder and / or an extrusion head; purging time of the respective material; material costs of the respective material

[0022] The preceding list is not exhaustive. Regarding the stability of the extruded product, the changeover strategy considers ensuring that the film bubble does not become unstable and tear under any circumstances. The risk of film tearing should be minimized. The temperature profile of an extruder and / or extrusion head is monitored, particularly in relation to the materials used. This prevents a situation where the temperature and materials used could cause at least some of the material to harden within the extruder or extrusion head. This would lead to a narrowing of the free flow cross-section and, at a later and entirely undesirable time, further melting would result in an unexpected change in the formulation.The flushing time for each material depends primarily on its viscosity. Furthermore, the materials used differ significantly in their associated material costs. Therefore, it makes sense to change in or out particularly expensive materials later or earlier. Naturally, it can be advantageous if the user can prioritize individual strategy parameters or change parameters to solve this multi-criteria optimization problem in a particularly simple and cost-effective manner.

[0023] It is further advantageous if, in a method according to the invention, at least one of the following operating aids is made available to the machine operator on a display device: Input recipe, input parameters of the extrusion device, subsequent recipe, subsequent parameters of the extrusion device, changeover status of at least one extruder and / or at least one material, rinsing status of a used material

[0024] The preceding list is not exhaustive. The terms "subsequent parameters" and "operating parameters" include, for example, temperature, the conveying speed of associated metering screws, and similar parameters. Such a display, which provides two or more of these parameters or operating aids, visualizes the changeover strategy. This prevents unwanted deviations from manual operating steps by the machine operator through appropriate visual clarification, or significantly reduces the associated risk. Furthermore, the current status information is communicated to the machine operator, thereby further improving the speed and safety of the changeover process.

[0025] It is also advantageous if, in a method according to the invention, the indication of at least one completion step and / or at least one preparation step is located at the point where the respective step is carried out. For example, an optical indicator, preferably with LEDs, and a corresponding color selection can be used to indicate the relevant preparation step and / or completion step at the point where it is required. For instance, an LED on a suction lance can indicate that the suction lance must be moved into another feed container at that point. A corresponding color selection can also reflect the different necessary steps. Thus, a specific color indicator can signify a specific completion step and / or preparation step. Of course, acoustic indicators are also conceivable.The necessary means for displaying each step can be provided by a display device at the respective location, or the machine operator can use a suitable mobile communication unit, for example a smartphone.

[0026] It is also advantageous if, in a method according to the invention, the confirmation is detected at the location of the step being performed. This achieves essentially the same advantages as explained in the preceding paragraph. For example, sensor surfaces for manual actuation are conceivable. Automatic detection using associated sensor signals is also conceivable within the scope of the present invention, allowing for even faster and more reliable changeovers. Here, too, a corresponding application on a mobile communication device or a smartphone of the machine operator is conceivable.

[0027] A further advantage is that, in a process according to the invention, the remaining time of a main material is displayed. This allows for time management, particularly of the necessary speed for the machine operator to perform manual steps. For example, the remaining time or the total duration of the input job is also displayed, thus providing the machine operator with a high density of information. Naturally, a timing strategy for the individual finishing or preparation steps can also be displayed, so that, for example, a new extruder should "arrive" in a corresponding film product every two minutes. This prevents premature changes between input materials and subsequent materials on a component-specific basis.

[0028] A further advantage arises when, in a method according to the invention, the machine operator recognizes a selection of a feed material to be changed within the feed recipe and subsequently uses this selected feed material in the process with a reduced initial quantity. This allows for a reduction in the residual quantity within the feed device, making such a reduced initial quantity achievable both manually and automatically. In particular, this reduction in residual material within the feed device results in both a reduction in rejects and a reduction in the required discharge time when draining the feed material.

[0029] Further advantages, features, 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 the description can each be essential to the invention individually or in any combination. The drawings schematically show: Fig. 1 shows an embodiment of an extrusion device according to the invention in normal operating condition, Fig. 2 shows the embodiment of the Fig. 1 In preparation for carrying out the material change, Fig. 3 shows the embodiment of the Fig. 1 and 2 upon reaching a change in fill level, Fig. 4 the embodiments of the Fig. 1 and 3 during the maintenance of a variable fill level, Fig. 5 the embodiments of the Fig. 1 bis 4 during a cleaning step, Fig. 6 the embodiments of the Fig. 1 bis 5 during the execution of a preparatory step, Fig. 7 shows a possible display device and the associated representation, and Fig. 8 shows an alternative embodiment of an extrusion device.

[0030] In the Fig. 1 bis 6 A schematic representation of an extrusion device 10 according to the invention is shown. Here, it is equipped with two feed devices 20, although of course three or more feed devices 20 can also be provided for the associated extruder 30. Such an extrusion device 10 can also be equipped with two or more extruders 30.

[0031] Each feed device 20 is equipped with a weighing hopper 22, a downpipe 24, and a feed container 26. The following refilling process can be carried out from top to bottom: Using a suction conveying system 29, the appropriate feed material E is drawn from a feed container, for example, a feed box or a silo, and introduced into the associated feed container 26. The entire feed device 20 is filled from top to bottom, as described by the Fig. 1 The figure shows that at the lower end, the feed material E is discharged via a corresponding hopper opening 23 to a metering screw 28 and metered by the screw into the corresponding extruder 30. A control device 40, equipped with a display device 12, is provided here for carrying out a process according to the invention.

[0032] To perform a material change from a starting material E to a subsequent material EF or from a starting formulation ER to a subsequent formulation EFR, the steps described below must be carried out with reference to the Fig. 1 bis 6 This will be explained in more detail. As soon as a material change request is detected, the fill level F of the input material E in the supply devices 20 is lowered. This continues until a corresponding changeover fill level WF has been reached in each supply device 20, which can be specifically designed for each individual supply device 20. The changeover fill level WF can be detected, for example, by a corresponding fill level sensor 42, which can detect the corresponding current fill level F when this changeover fill level WF is undershot. Fig. 3 It can be seen how, through continued dosing using the metering screw 28, the changeover fill level WF in the two feed devices 20 has been reached. If no changeover is to take place at this point, it is possible to ensure that the fill level F does not fall below the changeover fill level WF by refilling via the suction conveying system 29. In particular, a single refilling pulse is used to increase the fill level F again when the changeover fill level WF is reached and there is a risk of it falling below it. The situation after the refilling pulse is shown in Fig. 4 shown with a correspondingly increased fill level F of the input material E in the two feed devices 20.

[0033] If a desired change of material is now to be made, then in Fig. 5 The illustration shows how a drain closure 52 can be opened via corresponding drain openings 50 and the associated input material E is either drained into a drain container 60 or conveyed to a silo via an associated return device 70.

[0034] In Fig. 5 The figure illustrates how the cleaning process proceeds after the input material E has been introduced into a corresponding discharge container 60 or transported to a corresponding silo using a return device 70. In this case, the two feed devices 20 are essentially empty and contain only small residual amounts of input material E, in dust form or as individual granules. To remove these last traces from the feed devices 20, a cleaning device 80 is provided, which is schematically shown in two different embodiments on the left and right sides of the figure, respectively, in the two different feed devices 20. The cleaning device 80 can include one or more cleaning agents 82, which can exert different effects at different positions.Preferably, the cleaning agent 82 has a cleaning direction RR, which in particular correlates with a corresponding discharge direction AR. In this way, for example, a cyclone-like airflow can be achieved in the left feeder 20 by means of angled nozzles directed towards the side wall of the weighing hopper 22, in order to ensure the removal of any remaining particles of the feed material E. Two nozzles for the cleaning agent 82 are arranged in the feeder 26, the cleaning direction RR of which runs parallel to the discharge direction AR. Here, too, cleaning from above is possible for any remaining feed material E in the feeder 20. In the right feeder 20, an annular nozzle arrangement for a cleaning agent 82 is provided within the weighing hopper 22. Here, it becomes possible to create a circulating or...to generate a cylindrical airflow in order to provide particularly efficient cleaning. Furthermore, in the embodiment of the... Fig. 5 A dust sensor 84 is provided for the left feed device 20, with which the current dust situation can be detected and an adapted cleaning program can be selected for the cleaning device 80 accordingly.

[0035] The Fig. 6 This now shows the end of the finishing operations and the beginning of the preparation work for the subsequent formulation EFR or the subsequent material EF. This is now drawn in again using the suction conveying system 29 and, even while the feed material E is still inside the extruder 30, is stored again in the feed device 20 or in the associated feed hopper 26. This allows for a simple, fast, and, above all, significantly less mixing transition from the feed material E to the subsequent material EF.

[0036] In Fig. 7 The diagram schematically illustrates what can happen or be displayed on a display device 12 during the course of the switching process. The diagram shows that... Fig. 7 Four display options, sequentially linked by arrows, are revealed, which can be displayed on the display device 12 during the changeover process. Three fields are shown here, which can be specified as recipe change request 110, completion step 120, and preparation step 130. When transitioning from the upper left display to the upper right display, recipe change request 110 and completion step 120 are partially hatched. This indicates that a recipe change request 110 is present and a completion step 120 must be performed. When transitioning to the lower left on the display device 12, preparation step 130 is also partially hatched, and completion step 120 is fully hatched.This means that control unit 40 has already received confirmation of the completion of closing step 120 and is now indicating the execution of a preparation step 130. Once this has occurred for all closing steps 120 and all preparation steps 130, the system will display... Fig. 7 That all completion steps 120 and all preparation steps 130 are fully shaded. This means that the recipe change request 110 can now be completed and the new production start can begin.

[0037] The Fig. 8 shows an alternative embodiment of an extrusion device 10. With regard to the advantages described in the invention, this is based on the embodiment of Fig. 1 However, it differs in its refilling function. A batch process is provided for refilling. The feed hopper 26 is equipped with separate volumes, so that each volume of the feed hopper 26 can be considered a feed device 20. Components arranged below it, in the form of the downpipe 24 and the weighing hopper 22, are therefore common components of the different feed devices 20. A mixing hopper, in particular with a mixer drive, is provided below the weighing hopper 22, which allows homogenization before the material enters the extruder. Bezuaszeichenliste

[0038] 10. 60Ablassbehälter 62Ablassvolumen 70Rückführvorrichtung 80Reinigungsvorrichtung 82Reinigungsmittel 84Staubsensor EEssent material EREssent recipe EFFollowing material EFRollowing recipe BFOperating level WFInterchangeable level Ffilling level RRCleaning direction ARAdraining direction 110Rezepturwechselanforderung 120Abschlussschritt 130Vorbereitungsschritt

Claims

1. Method for the step-by-step guidance of a machine operator of an extrusion device (10) for a film machine when changing from an application formula (ER) to a subsequent formula (EFR), having the following steps of: - identifying a formula change request (110), - displaying the formula change request (110) for the machine operator, - displaying at least one final step (120) which has to be carried out for the application formula (ER), - Identifying a confirmation of the machine operator for the at least one final step (120), - displaying at least one preparation step (130) which has to be carried out for the subsequent formula (EFR), - identifying a confirmation of the machine operator for the at least one preparation step (130), - terminating the change from the application formula (ER) to the subsequent formula (EFR), characterized in that a guidance of the machine operator with feedback is provided so that a regular interaction between the actions of the machine operator, automatically carried out steps of the change and associated reconfirmations of the steps being carried out is provided. wherein for each final step which has to be carried out and each preparation step a corresponding display is carried out for the machine operator.

2. Method according to claim 1, characterized in that, after the identification of a confirmation of the machine operator, at least one automatic step is carried out as part of the change from the application formula (ER) to the subsequent formula (EFR), in particular at least one of the following: - cleaning a suction conveyor (29), - cleaning a storage container (26), - cleaning a weighing funnel (22), - cleaning a metering screw (28), - filling a storage container (26) with a subsequent material (EF) of the subsequent formula (EFR), - changing the temperature of an extruder (30).

3. Method according to any one of the preceding claims, characterized in that, when changing from the application formula (ER) to the subsequent formula (EFR), each application material (E) of the application formula (ER) is changed to a subsequent material (EF) of the subsequent formula (EFR).

4. Method according to claim 3, characterized in that the sequence of the processing of the change of the individual materials (E, EF) is predetermined as a change strategy.

5. Method according to claim 4, characterized in that the change strategy takes into account at least one of the following change parameters: - stability of the extrusion product, in particular a film bubble, - temperature profile of an extruder (30) and / or an extrusion head, - cleaning time of the respective material (E, EF), - material costs of the respective material (E, EF).

6. Method according to any one of the preceding claims, characterized in that on a display device (12) at least one of the following operating aids is provided to the machine operator: - application formula (ER), - application parameter of the extrusion device (10), - subsequent formula (EFR), - subsequent parameter of the extrusion device (10), - change status of at least one extruder (30) and / or at least one material (E, EF), - cleaning status of a cleaning material used.

7. Method according to any one of the preceding claims, characterized in that the display of the at least one final step (120) and / or the at least one preparation step (130) is carried out at the location at which the respective step is carried out.

8. Method according to any one of the preceding claims, characterized in that the identification of the confirmation is carried out at the location at which the step is carried out.

9. Method according to any one of the preceding claims, characterized in that a display of the remaining time of a main material (E, EF) is carried out.

10. Method according to any one of the preceding claims, characterized in that a selection of the machine operator of an application material (E) which is intended to be changed with the application formula (ER) is identified and subsequently this selected application material (EP) is carried with a reduced storage quantity in the process.