Packaging machine and method with foil feeding device

Abstract

The present application relates to a packaging machine and a method having a foil conveying device. The packaging machine (1) comprises a foil conveying device (25a, 25b, 25c) and a control system (13, 24) for controlling the operation of at least one drive unit (27, 28, 31, 32) of the foil conveying device (25a, 25b, 25c), wherein the control system (13, 24) is designed to activate the drive unit (27, 28, 31, 32) during a production run of the packaging machine (1) on the basis of a speed- and / or temperature-dependent friction torque characteristic curve (38), wherein the friction torque characteristic curve is detected by means of a measurement run of a rotational drive performed by the drive unit (27, 28, 31, 32). The present application also relates to a method for controlling a drive unit (27, 28, 31, 32) of a foil conveying device (25a, 25b, 25c).

Description

Technical Field

[0001] This invention relates to a packaging machine. This invention also relates to a method. Background Technology

[0002] In addition to the high reliability and performance of packaging machines, the reduction of packaging materials is a substantial demand from customers that packaging machine manufacturers increasingly face. This means adopting increasingly thinner foils and minimizing foil waste in packaging processes (especially foil edge strips that cannot be processed into packaging).

[0003] In practice, servo drives are already used in packaging machines, such as intermittent deep-draw packaging machines or pallet sealers, to start the foil take-up and foil remainder winder. With such servo drives, foil tension can be controlled via a default torque value. Therefore, customers can choose to adjust the foil tension individually, resulting in better foil delivery and leaving only a very narrow foil edge strip in the packaging process.

[0004] However, this indicates that conventional torque default control may be affected by disturbance variables that occur during packaging processes, such as changes in operating temperature and / or changes in servo motor speed, making it impossible to achieve constant and reproducible foil tension during packaging processes.

[0005] First, the operation-related dynamics of the individual drives used in the foil conveying device can be problematic because they may cause varying foil tension during the production run or packaging process of the packaging machine. However, while varying foil tension during production run can lead to fatigue only in thin foil, it can also cause visible damage to the foil material during production run, such as in cracks at fatigue points. The resulting interruptions to production run (optionally re-clamping the foil material) reduce the productivity of the packaging machine. Summary of the Invention

[0006] The object of the present invention is to provide a packaging machine and method, wherein the packaging machine and method can better handle thin foil materials.

[0007] This objective is achieved by the packaging machine and method according to the invention. Advantageous developments of the invention are given by the corresponding subject matter of the dependent claims.

[0008] This invention relates to a packaging machine having a foil conveying device and a control system for controlling the operation of at least one drive unit of the foil conveying device. The packaging machine according to the invention is particularly found in the form of a deep-draw packaging machine or a pallet sealing machine, also known by experts as a pallet sealer.

[0009] According to the present invention, the control system is designed to activate the drive unit during the production operation of the packaging machine based on a frictional torque characteristic curve that depends on rate and / or temperature, wherein the frictional torque characteristic curve is detected by means of a measurement run of rotational drive performed by the drive unit.

[0010] The measurement operation performed by the drive unit is conducted separately from the production operation, that is, separately from the packaging process of the packaging machine. In this invention, the measurement operation is used to determine the self-friction, which can be measured at the drive unit and varies due to operation. Therefore, the measurement operation is performed as a friction detection operation, serving as the basis for the actual production operation performed by the packaging machine.

[0011] The characteristic process of self-friction measurable at the drive unit can be derived, for example, proportional to the power supply required for measurement operation, and this characteristic process can be detected at the drive unit. Then, the resulting frictional torque characteristic curve is considered in actual production operation to start the drive unit, thereby maintaining the desired foil tension—that is, no change in tension—despite the continuous variation in the self-frictional torque of the drive unit. In other words, this invention compensates for the self-friction of the drive unit detected by measurement operation during production operation, thereby resulting in constant foil tension during production operation.

[0012] By means of the frictional torque characteristic curve detected for the drive unit through a measurement run performed at the drive unit (which can be determined, for example, proportional to the rate-dependent current feed of the drive unit detected during the measurement run), the self-friction of the drive unit can be detected and taken as the basis for starting the drive unit during a separately executed production run (particularly directly subsequently or only later) to achieve constant foil tension. Therefore, the measurement run performed for production operation is used to detect the frictional dynamics of the drive unit, which are taken into account during startup in production operation to prevent the foil material from being subjected to varying stresses. Thus, very thin foils can be reliably processed into perfect packaging.

[0013] By utilizing the frictional torque characteristic curve determined through measurement operation, the mechanical effects of the self-friction of the drive unit can be detected at least at various rates suitable for production operation, and this effect can be compensated for during the corresponding startup of the drive unit. Therefore, current can be supplied at the drive unit such that the current supply assumed to achieve the desired foil tension is corrected relative to the self-frictional torque of the drive unit, which is detected by measurement operation at its assumed rate.

[0014] Specifically, the measurement run can be performed as a speed-dependent (meaning rate-dependent) friction detection run to determine the self-friction of the drive unit. It is practical to perform the measurement run without any foil material. Depending on the variant, the measurement run can be performed based on operating hours (e.g., at regular intervals) to account for the current self-friction of the drive unit. It is conceivable that the measurement run function could be invoked by the operator at the packaging machine (e.g., at an operator terminal provided there).

[0015] The foil conveying device can be an upper foil conveyor for conveying upper foil and / or a lower foil conveyor for conveying lower foil, wherein, through the upper foil conveyor and / or lower foil conveyor, the upper foil and / or lower foil can be supplied with the desired foil tension to the work processing performed at the packaging machine during production operation. Specifically, the upper foil conveyor is designed to supply upper foil to the sealing station of a deep-draw packaging machine or a pallet sealer. The lower foil conveyor can be used at a deep-draw packaging machine to supply lower foil to the forming station of the deep-draw packaging machine.

[0016] Preferably, the drive unit includes a servo driver. This may include a servo motor and a servo controller, wherein the servo controller dynamically controls the operation of the drive unit based on a friction torque characteristic curve to achieve constant foil tension during production operation. The power supply to the drive unit on which the friction torque characteristic curve is based can be switched on to compensate for the drive unit's own friction, as a pre-control of the characteristic curve depending on disturbance variables, and / or as a feedforward of disturbance variables to the servo driver (especially the servo controller).

[0017] Specifically, the drive unit includes a transmission, particularly a transmission with multiple speed ranges. The transmission and servo motor each have their own friction that can affect the foil tension. However, the corresponding frictional torque of the drive unit can be determined cumulatively by measuring the operation, and thus the corresponding frictional torque can be systematically considered during the start-up of the drive unit using the obtained frictional torque characteristic curve.

[0018] It is conceivable that the drive unit is activated to detect the frictional torque characteristic curve within the total speed range of the drive unit. For this purpose, the drive unit can be continuously accelerated from its rest during the measurement operation until it reaches its maximum speed. Thus, the self-friction of the drive unit can be detected within the total speed range, for example at different speed stages, and used as the basis for activating the drive unit during production operation. The results of the friction detection operation can be stored by means of an electronic storage unit in the control system for future use in the packaging process of the packaging machine.

[0019] Preferably, the drive unit can be accelerated during the measurement operation used to detect the frictional torque characteristic curve by means of a gradually increasing rate level (i.e., by means of increasingly faster speed phases). In particular, if a substantially constant current feed can be measured for the corresponding speed phase, the frictional torque can be reliably detected by means of the increased speed phase. This is depicted in the power curve by the steady-state period.

[0020] It is conceivable that the control system includes a filtering function to temporarily filter out power peaks that occur due to the increase in speed, with each power peak occurring at the beginning of the speed phase regulated during the measurement run. The friction torque characteristic curve of the drive unit is specifically proportional to the power supply detected during the measurement run. It is conceivable that the control system is configured to generate an interpolated friction torque characteristic curve based on the multiple friction torques detected during the measurement run.

[0021] According to one variation, the control system is designed to determine the measured operating temperature of the drive unit, which is rotary-driven, during measurement operation. For this purpose, the drive unit, particularly a servo motor formed thereon, may include at least one temperature sensor, by means of which the measured operating temperature can be detected during friction detection operation. Preferably, the temperature sensor can also be used to measure the current operating temperature of the drive unit during production operation.

[0022] In one practical variation, a measurement run is performed to record the frictional torque characteristic curve during a constant measurement run temperature. For the accuracy of drive unit startup during production operation, a measurement run temperature range of 3°C to 8°C, particularly 5°C to 6°C, is shown to be suitable for detecting the relevant frictional torque characteristic curve. First, the control system can select the time window for the measurement run, allowing it to be performed at a constant measurement run temperature. It has been demonstrated that performing the measurement run at a constant measurement run temperature of 5°C is feasible.

[0023] In a preferred variant, the control system is configured to determine a temperature compensation factor for starting the drive unit, derived from the friction torque-temperature characteristic curve, based on at least one friction torque-temperature characteristic curve stored in the control system for the drive unit, taking into account the currently detected operating temperature of the drive unit and the measured operating temperature detected during the measured operation.

[0024] Specifically, the control system is designed to correct for the rate-dependent frictional torque characteristic curve detected by measuring operation, particularly the required power supply of the drive unit derived from this curve, to achieve the desired foil tension determined using the currently dominant operating temperature at the drive unit. Thus, the self-friction, which tends to decrease with increasing operating temperature during production operation, can be taken into account during drive unit startup. With such temperature compensation, the desired foil tension can be maintained even better during production operation.

[0025] For the drive unit, i.e., for its modular structure, the friction torque temperature characteristic curve only needs to be determined once. The friction torque temperature characteristic curve will be determined considering the individual functional units of the drive unit. Tests show that within the transmission series used for the drive unit, the deviation in friction torque temperature behavior is very low and therefore negligible.

[0026] First, the temperature compensation factor can be derived from the friction torque temperature characteristic curves stored in the control system for the corresponding drive units, as a temperature-dependent quotient. Specifically, considering the friction torque temperature characteristic curves, the quotient is calculated using the friction torque indicated from these curves for the current operating temperature and the friction force indicated from the same curves considering the measured operating temperature.

[0027] During production operation, the actual power supply required for the current operating temperature, based on the assumption of the friction torque characteristic curve, can be continuously derived preferably using a temperature compensation factor determined for the current operating temperature and the measured operating temperature of the drive unit. This ensures a constant foil tension even as the operating temperature of the drive unit increases during production operation. As the operating temperature increases, the actual power torque required to achieve the desired foil tension decreases proportionally, thereby compensating for the temperature effects on the frictional behavior of the drive unit. Consequently, even with variations in the operating temperature of the drive unit, a constant and reproducible foil tension can be advantageously achieved during production operation, allowing the use of very thin foils.

[0028] As described above, the packaging machine can be implemented as a deep-draw packaging machine or a pallet sealer. In the form of a deep-draw packaging machine, the foil conveying device can exist as an upper foil conveying device to supply the upper foil to the sealing station of the deep-draw packaging machine with the desired foil tension. Such an upper foil conveying device can be similarly formed at the pallet sealer.

[0029] Preferably, the foil conveying device includes at least one additional drive unit, and the control system is designed to activate the additional drive unit during production operation of the packaging machine based on an additional frictional torque characteristic curve that depends on rate and / or temperature, wherein the additional frictional torque characteristic curve is detected by means of a measurement run performed by the rotational drive executed by the additional drive unit. Thus, the two drive units can operate based on their own friction, such that the two drive units together convey the foil clamped between them with a constant and reproducible foil tension during production operation.

[0030] For all drive units used in foil conveying devices, such as during and / or at the commissioning of the packaging machine, corresponding measurement runs can be performed to detect the respective friction torque characteristic curves of the respective drive units and store them in the control system.

[0031] The foil conveying device according to the invention can be a lower foil conveying device at a deep-draw packaging machine to supply lower foil installed at the inlet of the deep-draw packaging machine along the production direction to a forming station located downstream, so as to produce a groove by means of a desired foil tension. Here, the desired foil tension can be achieved because the dynamic start of the drive unit of the foil roller mount installed at the inlet of the deep-draw packaging machine is performed based on the friction torque characteristic curve, and the dynamic start of other drive units is performed based on other friction torque characteristic curves, which, taking into account the cycle of the packaging machine, moves the clamping chain for the lower foil in the production direction.

[0032] The measurement operation of other drive units can be initiated in a manner similar to that described above for the drive units of the present invention. In particular, the drive units of the present invention and other drive units can be initiated in a coordinated manner, such that these drive units can compensate for the temperature effects present at these drive units individually during production operation, in order to achieve constant and reproducible foil tension together.

[0033] It is conceivable that the drive unit rotates the foil take-up coil, and other drive units rotate the foil rewound coil. Specifically, the desired foil tension can be adjusted separately for different foil types at the control system, achieving a constant and reproducible foil tension despite temperature changes during production operation. Alternatively or supplementarily, such adjustment functionality can also be provided directly at the foil take-up coil and / or foil rewound coil.

[0034] The present invention also relates to a method for controlling at least one drive unit of a foil conveying device that supplies foil with a predetermined foil tension to a workstation of a packaging machine during production operation at the packaging machine. Specifically, the foil conveying device is configured to supply upper foil with a predetermined foil tension to a sealing station of the packaging machine during production operation at the packaging machine. Alternatively, the foil conveying device can be used to supply lower foil with a predetermined foil tension to a forming station of the packaging machine.

[0035] According to the present invention, during the production operation of the packaging machine, the drive unit is controlled based on a frictional torque characteristic curve dependent on rate and / or temperature, wherein the frictional torque characteristic curve is detected by means of a measuring run performed by the drive unit. Regardless of whether the foil conveying device is used to convey upper or lower foil, a constant and reproducible foil tension can be better maintained in the foil material during production operation. This is due to the fact that the dynamics of the drive unit itself can be largely compensated for during the startup of the drive unit, taking into account the frictional torque characteristic curve detected by means of a measuring run.

[0036] It is meaningful for the drive unit to rotate in both directions during a predetermined break-in period before the start of the measurement run. By means of a break-in period conducted in opposite directions in this way, the adhesion effect can be removed at the drive unit, thereby allowing for more accurate subsequent measurement runs to detect the self-friction of the drive unit, preferably by gradually detecting the self-friction of the drive unit within the total rate range.

[0037] During the measurement portion of the operation following the break-in period, the drive unit is progressively accelerated at a continuously increasing rate to determine the friction torque characteristic curve, which is convenient. This results in a progressively increasing rate characteristic curve. Based on this, the current feed to the drive unit, which is proportional to the power torque present at the drive unit, can be measured.

[0038] Specifically, the measurement operation can be controlled to make the rate jumps continuously larger. Therefore, the self-friction of the drive unit can be recorded more accurately. Firstly, this allows for the determination of a measurement time window during which no temperature change of the drive unit occurs.

[0039] Preferably, the control system determines a temperature compensation factor for starting the drive unit based on the friction torque-temperature characteristic curve stored thereon for the drive unit, taking into account the currently detected operating temperature of the drive unit during production operation and the measured operating temperature detected during measurement operation. With the aid of the temperature compensation factor, the control system can compensate for the temperature-dependent self-friction of the drive unit during production operation. In other words, the control system can thus continuously determine a temperature compensation factor dynamically adapted to the current operating temperature of the drive unit during production operation, and continuously employ this temperature compensation factor during the startup of the drive unit to compensate for temperature-dependent self-friction. With this temperature compensation, a constant and reproducible foil tension can be achieved during production operation.

[0040] In an advantageous variant, the control system derives the power supply for the drive unit to achieve the desired foil tension from the detected frictional torque characteristic curve during production operation, and dynamically adjusts this assumed power supply using a temperature compensation factor determined taking into account the current operating temperature. Therefore, the characteristic curve of the drive unit's own friction, determined by measuring the operation of the drive unit, can be used to supply the actual required power supply for the drive unit, dynamically adjusted by the temperature compensation factor, to supply the foil material to the packaging process with the desired constant and reproducible foil tension.

[0041] Based on the measured operating temperature during friction detection operation and taking into account the current operating temperature of the drive unit, a quotient can be derived from the friction torque-temperature characteristic curve stored in the control system. This quotient indicates a temperature compensation factor for the current operating temperature. Therefore, taking into account the self-friction present at the drive unit and the operating temperature detected at the drive unit, the actual power supply required by the drive unit can be dynamically determined during production operation to deliver foil material with constant foil tension.

[0042] With this invention, the intrinsic frictional characteristics of a drive unit, including a servo motor, a gearbox, and / or bearings formed thereon, can be recorded by measuring the performance of the operation and the resulting frictional torque characteristic curves. These intrinsic frictional characteristics imply the drive unit's general, rate- and / or temperature-dependent self-dynamics. Furthermore, considering the drive unit's specific (i.e., currently measured) operating temperature, a temperature compensation factor can be used to adjust the frictional torque derived therefrom for the desired foil tension, or the power supply to the drive unit for achieving the desired foil tension, to compensate for the effects of varying operating temperatures during production operation on the drive unit's frictional behavior, ensuring that the foil tension remains highly constant and reproducible during production operation. Attached Figure Description

[0043] The invention will be described in more detail with reference to the following figures. In the figures:

[0044] Figure 1 A schematic side view of a packaging machine implemented as a deep-draw packaging machine is shown.

[0045] Figure 2 A perspective view of a packaging machine that functions as a pallet sealer is shown.

[0046] Figure 3 The measurement operation or friction detection operation of the drive unit of the foil conveying device of the packaging machine is shown, as well as

[0047] Figure 4 The friction torque-temperature characteristic curve used to determine the temperature compensation factor is shown.

[0048] In the accompanying drawings, the same components are always provided with the same reference numerals. Detailed Implementation

[0049] Figure 1 A schematic side view shows a packaging machine 1 implementing a deep-draw packaging machine 2 for intermittent operation. The deep-draw packaging machine 2 includes a forming station 3, a sealing station 4, a transverse cutter 5, and a longitudinal cutter 6 arranged sequentially along the conveying direction R on a frame 7. At the inlet side, a feed roller 8 is located on the frame 7, from which a lower foil 9 is wound up. Furthermore, the deep-draw packaging machine 2 includes a conveyor chain 11, particularly conveyor chains 11 or clamping chains arranged on both sides, which clamp the lower foil 9 and further convey the lower foil 9 along the conveying direction R in each main cycle.

[0050] In the illustrated embodiment, the forming station 3 is implemented as a deep drawing station, in which grooves M are formed into the lower foil 9 by deep drawing, for example by means of compressed air and / or vacuum. The forming station 3 can be designed such that a plurality of grooves M are formed adjacent to each other in a direction perpendicular to the conveying direction R. A filling section 10 is provided downstream of the forming station 3 in the conveying direction R, in which the grooves M formed in the lower foil 9 are filled with the product.

[0051] The sealing station 4 has a gas-tight chamber 4a, wherein the gas environment in the tank M is, for example, vented and / or replaced by a substitute gas or gas mixture by gas flushing before the upper foil 30 discharged by the upper foil conveying device 12 seals the tank M.

[0052] The transverse cutter 5 can be implemented as a press that cuts through the lower foil 9 and upper foil 30 between adjacent slots M in a direction transverse to the conveying direction R. In this process, the transverse cutter 5 operates such that the lower foil 9 is not cut through its entire width, but at least not in the edge region. This allows for controlled further conveying via the conveyor chain 11.

[0053] The longitudinal cutter 6 can be configured as a blade, in which the lower foil 9 and the upper foil 30 are cut through in the conveying direction R between adjacent slots M and at the side edge of the lower foil 9, so that a single package V is provided downstream of the longitudinal cutter 6.

[0054] Furthermore, the deep-draw packaging machine 2 includes a control system 13. The latter has the task of controlling and monitoring the processing operations within the deep-draw packaging machine 2. A display device 14 with an operation controller 15 is used to visualize or influence the processing operations within the deep-draw packaging machine 2 for the operator or by the operator.

[0055] Figure 2 A pallet sealer 16 is shown. This is also referred to by experts as a pallet sealing machine. A packaging bowl S is positioned at the pallet sealer 16 on a feed belt 17. The pallet sealer 16 has a gripper device 18 by which the packaging bowl S on the feed belt 17 is picked up and conveyed to the lower sealing tool section 19 of the sealing station 20 for pallet sealing operation. During the pallet sealing operation, the lower sealing tool section 19 is raised against the upper sealing tool section 21 located above it to seal the packaging bowl S using the upper foil 22 guided through the sealing station 20. Gas treatment can be performed before the pallet sealing operation via the upper sealing tool section 21 and / or the lower sealing tool section 19 to create a desired gas environment within the packaging bowl S located in the sealing station 20. After the pallet sealing operation, the sealing station 20 is opened by lowering the lower sealing tool section 19. The package sealed with the desired atmosphere can now be picked up by means of the gripper device 18 and conveyed to the discharge belt 23.

[0056] Figure 2 The tray sealer 16 has a control system 24. The latter has the task of controlling and monitoring the processing running in the deep-draw packaging machine 16.

[0057] exist Figure 1 and Figure 2 As shown in the packaging machine diagram, this means that at the deep-draw packaging machine 2 and the pallet sealer 16, it is advantageous to supply the corresponding foil to the corresponding workstation with a certain constant foil tension that can be reproduced for each machine cycle.

[0058] In the deep-draw packaging machine 1, a lower foil conveying device 26 is used as a foil conveying device 25a at the inlet of the deep-draw packaging machine 1. The lower foil conveying device 26 includes a drive unit 27. The control system 13 is configured to control the operation of the drive unit 27. By means of the activation of the drive unit 27 and other drive units (not shown) of the conveyor chain 11, the lower foil 9 can be supplied to the forming station 3 with the desired foil tension for the forming process that occurs in the forming station.

[0059] also, Figure 1 An upper foil conveying device 12, serving as a foil conveying device 25b, is shown. The upper foil conveying device 12 includes a drive unit 28 to supply the upper foil 30 to the sealing station 4 with a desired foil tension. The upper foil conveying device 12 can be activated by means of a control system 13, such that the upper foil 30 is supplied to the sealing station 4 with the desired foil tension. The drive unit 28 of the upper foil conveying device 12 can be activated in a manner coordinated with the conveyor chain 11 to achieve the desired foil tension in the upper foil 30.

[0060] exist Figure 2 In this process, as foil conveying device 25c, another upper foil conveying device 29 is provided, which is configured to supply the upper foil 22 to the sealing station 20 with the desired foil tension. Figure 2 The upper foil conveying device 29 shown has a drive unit 31 that can be activated by means of a control system 24. The tray sealer 16 also has a foil rewinder 42 for winding the remaining upper foil 22 after the sealing process. The drive unit 31 and drive unit 32 of the foil rewinder 42 can be activated by means of the control system 24 for controlled foil conveying with desired foil tension.

[0061] Figure 3 It shows the use of Figure 1 and Figure 2 The rate diagram is generated by one of the drive units 27, 28, 31, 32 or not shown. Figure 3 The rate graph illustrates the break-in period 33. During break-in period 33, drive units 27, 28, 31, and 32 move in two directions to remove adhesion effects. Subsequently, a measurement run 34 is performed. During measurement run 34, drive units 27, 28, 31, and 32 gradually accelerate within their total rate range. By means of measurement run 34 performed in this manner, the self-friction of drive units 27, 28, 31, and 32 can be determined for the corresponding rate stage. Therefore, measurement run 34 represents the friction detection run of each drive unit 27, 28, 31, and 32.

[0062] Figure 3 The diagram illustrates the phase during measurement run 34 where the execution rate increases progressively. Along the resulting constant speed stabilization period 40, the resulting frictional torque of the drive units 27, 28, 31, and 32 can be detected. Here, the corresponding frictional torque is proportional to the power supply for the corresponding speed stabilization period 40, the progress of which is as follows: Figure 3 It is shown below the rate curve.

[0063] first, Figure 3This illustrates the transition 35 between static and sliding friction that can be measured at drive units 27, 28, 31, and 32, directly at the start of measurement run 34, during the transition to the first speed stabilization period 40. This transition 35... Figure 3 The increase in current intensity between the break-in period 33 and the measurement operation 34 is illustrated in the figure.

[0064] Figure 3 It is also shown that, in the current process illustrated therein, an increase in the rate at the beginning of the speed stabilization period 40 results in a peak power 41 in the power supply. However, the peak power 41 caused by the controlled rate increase at the beginning of the corresponding speed stabilization period 40 then flattens out with a constant rate. The frictional torque characteristic curve 38 (see [reference]) can be determined by means of the control systems 13, 24 using the substantially smooth power supply value for the speed stabilization period 40 that appears during the measurement operation 34. Figure 4 ).

[0065] Figure 4 Frictional torque-temperature characteristic curve 36 is shown, which can be stored, for example, for use in one of drive units 27, 28, 31, 32, or for one of the aforementioned but not shown drive units of control systems 13, 24.

[0066] With the help of Figure 4 The friction torque-temperature characteristic curve 36 shown can be used to determine the temperature compensation factor 37 for the corresponding drive units 27, 28, 31, and 32. The temperature compensation factor 37 is calculated using a quotient of torque and friction force, where the torque is depicted relative to the current measured operating temperature of the drive units 27, 28, 31, and 32 using the friction torque-temperature characteristic curve 36, which contains the friction torque already applied in the friction torque-temperature characteristic curve 36. Figure 3 The measurement was performed at a temperature of 34°C.

[0067] With the help of temperature compensation factor 37, taking into account the current operating temperatures of drive units 27, 28, 31, and 32, adjustments can be made. Figure 3 The desired foil tension requires a rate (which means power supply based on the friction torque characteristic curve 38, which is an assumption for this purpose), so that constant foil tension can be achieved during production operation even at varying operating temperatures of the drive units 27, 28, 31, 32.

[0068] exist Figure 4 In the example, the friction torque from the friction torque-temperature characteristic curve 36 for an operating temperature of 15°C is determined, where according to Figure 4 The frictional torque is approximately 6 Nm. Furthermore, assuming... Figure 3 The measurement operation 34 has been conducted at a measurement operation temperature of 5°C. Figure 4 The friction torque-temperature characteristic curve 36 indicates a friction torque of 9 Nm at 5 °C, such that the quotient from the corresponding friction torque is 2 / 3.

[0069] also, Figure 4 The frictional torque characteristic curve 38 is shown only schematically, which is achieved by means of measurement operation 34, i.e., depends on the drive units 27, 28, 31, 32 required for measurement operation 34, and in Figure 3 The power supply is shown in the figure. Based on the friction torque characteristic curve 38, for drive units 27, 28, 31, and 32, control systems 13 and 24 can use a temperature compensation factor 37 to determine the power supply 38' compensated for the operating temperature 15 measured during production operation. With the aid of this temperature compensation factor 37, drive units 27, 28, 31, and 32 can be operated to maintain constant foil tension at an operating temperature of 15°C. Here, the assumed power supply obtained through the measurement operation 34 for the rate at which foil tension is achieved is corrected by the temperature compensation factor 37.

[0070] Figure 3 and Figure 4 It is shown that the power supply can be adjusted by means of a calculable temperature compensation factor 37 to calculate the power supply of drive units 27, 28, 31, 32 actually required for the detected operating temperature to achieve constant and reproducible foil tension, wherein the changes in the operating temperature of drive units 27, 28, 31, 32 during production operation caused by the operation of drive units 27, 28, 31, 32 can be taken into account, and the power supply is derived from the measurement operation 34 to achieve a specific desired foil tension.

Claims

1. A packaging machine (1) comprising a foil conveying device (25a, 25b, 25c) and a control system (13, 24) for controlling the operation of at least one drive unit (27, 28, 31, 32) of the foil conveying device (25a, 25b, 25c), characterized in that, The control system (13, 24) is designed to activate the drive units (27, 28, 31, 32) based on a frictional torque characteristic curve (38) dependent on rate and / or temperature during the production operation of the packaging machine (1), wherein the frictional torque characteristic curve is detected by means of a measurement run of rotational drive performed by the drive units (27, 28, 31, 32), the measurement run being performed separately from the production operation.

2. The packaging machine according to claim 1, characterized in that, The drive units (27, 28, 31, 32) include servo drivers.

3. The packaging machine according to claim 1 or 2, characterized in that, The drive units (27, 28, 31, 32) can be activated to detect the friction torque characteristic curve (38) within the total rate range of the drive units (27, 28, 31, 32), and / or the drive units (27, 28, 31, 32) can be activated to a progressively increasing rate level (40) to detect the friction torque characteristic curve (38).

4. The packaging machine according to claim 1 or 2, characterized in that, The control system (13, 24) is designed to determine the measurement operating temperature (T) of the drive units (27, 28, 31, 32) that are rotated during the measurement operation (34). M ).

5. The packaging machine according to claim 4, characterized in that, The control system (13, 24) is configured to determine a temperature compensation factor (37) for starting the drive units (27, 28, 31, 32) based on the friction torque-temperature characteristic curves (36) stored in the control system (13, 24) for the drive units (27, 28, 31, 32), wherein the temperature compensation factor (37) takes into account the currently detected operating temperature (T) of the drive units (27, 28, 31, 32). P And taking into account the measurement operation temperature (T) detected during the measurement operation (34). M This is derived from the friction torque-temperature characteristic curve (36).

6. The packaging machine according to claim 1 or 2, characterized in that, The packaging machine (1) is a deep-draw packaging machine (2) or a pallet sealer (16).

7. The packaging machine according to claim 1 or 2, characterized in that, The foil conveying devices (25a, 25b, 25c) include other drive units, and the control system (13, 24) is designed to activate the other drive units during the production operation of the packaging machine (1) based on a frictional torque characteristic curve (38) that depends on rate and / or temperature, wherein the frictional torque characteristic curve is detected by means of a measurement run (34) of rotational drive performed by the other drive units.

8. A method for controlling at least one drive unit (27, 28, 31, 32) of a foil conveying device (25a, 25b, 25c), wherein the foil conveying device (25a, 25b, 25c) supplies foil (9, 22, 30) to a workstation of the packaging machine (1) at a predetermined foil tension during production operation at the packaging machine (1), characterized in that, The drive units (27, 28, 31, 32) are controlled during the production operation of the packaging machine (1) based on a frictional torque characteristic curve (38) that depends on rate and / or temperature, wherein the frictional torque characteristic curve is detected by means of a measurement run (34) of rotational drive performed by the drive units (27, 28, 31, 32), which is performed separately from the production operation.

9. The method according to claim 8, characterized in that, The control system (13, 24) is based on the friction torque-temperature characteristic curves (36) of the drive units (27, 28, 31, 32) stored in the control system (13, 24), taking into account the operating temperature (T) of the drive units (27, 28, 31, 32) currently detected during the production operation. P ) and taking into account the measurement operation temperature (T) detected during the measurement operation (34). M ), to determine the temperature compensation factor (37) used to start the drive units (27, 28, 31, 32).

10. The method according to claim 9, characterized in that, The control system (13, 24) derives the power supply (I) of the drive units (27, 28, 31, 32) for achieving the desired foil tension from the detected frictional torque characteristic curve (38) during production operation, and by taking into account the current operating temperature (T) P The power supply (I) is dynamically adjusted using the temperature compensation factor (37) determined by the temperature compensation factor (37).

11. The method according to any one of claims 8 to 10, characterized in that, The drive units (27, 28, 31, 32) rotate in two directions during the predetermined break-in period (33) prior to the measurement run (34).

12. The method according to claim 11, characterized in that, During the measurement portion of the measurement run (34) conducted after the break-in period (33), the drive unit (27, 28, 31, 32) is gradually accelerated at a continuously increasing rate to determine the friction torque characteristic curve (38).

Images