Method for testing the function of a tubular bag machine

Abstract

A method for testing a tubular bag machine, the tubular bag machine having multiple electronic drive units controlled independently by a drive control system for driving functional elements of the packing machine in a cycle time-synchronous manner during predefined motion sequences, one drive unit being a transverse sealing unit comprising a motor and two transverse sealing jaws for transversely sealing a film tube, the drive torque being measured using a drive controller, and the position of the drive motor measured using a position sensor, by removing the film tube from the sealing zone between the transverse sealing jaws, closing the jaws according to a predefined target torque stored in the drive control system; measuring the actual position of the drive motor at the target torque; and comparing the measured actual position to a target position stored in the drive control system and associated with the predefined target torque.

Claims

1. A method for testing the function of a tubular bag machine, the tubular bag machine comprising a drive control system and multiple electronic drive units which are controlled independently of each other by the drive control system and which drive different functional elements of the tubular bag machine in a cycle time-synchronous manner as they are going through predefined motion sequences, and one drive unit being realized in the manner of a transverse sealing unit, and the transverse sealing unit comprising at least one drive motor (02) and two transverse sealing jaws (13a, 13b) which are driven relative to each other by the drive motor (02) and by means of which a film tube (09) is sealed transversely to a conveying direction (21), and a drive torque (M) of the drive motor (02) being measured directly or indirectly using a drive controller, and a position (φ) of the drive motor (02) being measured directly or indirectly using a position sensor, the method comprising the following steps: a) removing the film tube (09) from a sealing zone between the transverse sealing jaws (13a, 13b); b) closing the transverse sealing jaws (13a, 13b) according to a predefined target torque stored in the drive control system; c) measuring an actual position of the drive motor (02) once the target torque has been reached; d) comparing the measured actual position to a target position stored in the drive control system and associated with the predefined target torque; wherein multiple different target torques each having an associated target position are stored in the drive control system, method steps b), c) and d) being repeated one after the other for the different target torques and their associated target positions.

2. The method according to claim 1, characterized in that to determine the target positions, the transverse sealing unit is first calibrated, and then the actual positions reached are measured for different target torques, the actual positions thus measured being stored in the drive control system as target positions associated with the respective target torques.

3. The method according to claim 1, characterized in that method steps a), b), c) and d) are carried out at a reference temperature stored in the drive control system.

4. The method according to claim 3, characterized in that the reference temperature corresponds to a measured temperature at which the target positions or the target torques were determined by measuring actual positions of the transverse sealing unit.

5. The method according to claim 1, further comprising determining a difference between the target position and the actual position and comparing said difference to a tolerance threshold (30, 31) stored in the drive control system, an error being reported if the tolerance threshold (30, 31) is exceeded.

6. The method according to claim 1, characterized in that the actual position is measured directly using a rotation angle sensor.

7. The method according to claim 1, characterized in that method steps a), b), c) and d) are carried out after the transverse sealing jaws have been replaced.

8. The method according to claim 1, characterized in that method steps a), b), c) and d) are carried out after a disruption of the operation of the tubular bag machine.

9. The method according to claim 1, characterized in that the drive units go through a motion sequence for the intermittent production of tubular bags.

10. The method according to claim 1, characterized in that the drive units go through a motion sequence for the continuous production of tubular bags.

11. A method for testing the function of a tubular bag machine, the tubular bag machine comprising a drive control system and multiple electronic drive units which are controlled independently of each other by the drive control system and which drive different functional elements of the tubular bag machine in a cycle time-synchronous manner as they are going through predefined motion sequences, and one drive unit being realized in the manner of a transverse sealing unit, and the transverse sealing unit comprising at least one drive motor (02) and two transverse sealing jaws (13a, 13b) which are driven relative to each other by the drive motor (02) and by means of which a film tube (09) is sealed transversely to a conveying direction (21), and a drive torque (M) of the drive motor (02) being measured directly or indirectly using a drive controller, and a position (q) of the drive motor (02) being measured directly or indirectly using a position sensor, the method comprising the following steps: a) removing the film tube (09) from a sealing zone between the transverse sealing jaws (13a, 13b); b) closing the transverse sealing jaws (13a, 13b) according to a predefined target position stored in the drive control system; c) measuring an actual torque of the drive motor once the target position has been reached; d) comparing the measured actual torque to a target torque stored in the drive control system and associated with the predefined target position; wherein multiple different target positions each having an associated target torque are stored in the drive control system, method steps b), c) and d) being repeated one after the other for the different target positions and their associated target torques.

12. The method according to claim 11, characterized in that to determine the target torques, the transverse sealing unit is first calibrated, and then the actual torques reached are measured for different target positions, the actual torques thus measured being stored in the drive control system as target torques associated with the respective target positions.

13. The method according to claim 11, characterized in that the actual torque is measured indirectly by the drive controller of the drive motor (02).

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) FIG. 1 shows a schematic side view of the transverse sealing unit of a known tubular bag machine;

(2) FIG. 2 shows a diagram relating to the determination of the target positions associated with the different target torques;

(3) FIG. 3 shows the diagram according to FIG. 2 after implementation of tolerance thresholds;

(4) FIG. 4 shows the diagram according to FIG. 3 after determination of actual positions during a first function test;

(5) FIG. 5 shows the diagram according to FIG. 3 after determination of actual positions during a second function test.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 is a schematic of an example of the transverse sealing unit of a tubular bag machine comprising two transverse sealing jaws 13a and 13b which are moveable relative to each other.

(7) An endlessly produced film tube 09 which can be filled with material to be packaged by means of a filling tube 08 is visible in FIG. 1. Film tube 09 is transported in conveying direction 21. To produce the individual tubular bags, film tube 09 is sealed transversely. Transverse sealing jaws 13a and 13b are used to do so. Said transverse sealing jaws 13a and 13b can be moved toward each other and away from each other in transverse direction 22 transversely to conveying direction 21. In the sealing position, transverse sealing jaws 13a and 13b are moved against each other so that film tube 09 located between them can be compressed and sealed by heating transverse sealing jaws 13a and 13b. The technique for the transverse sealing of tubular bags is known in principle and requires no further explanation.

(8) In the exemplary embodiment illustrated in FIG. 1, transverse sealing jaws 13a and 13b are each disposed on support bars 16 which are mounted in a support bar mount 17 so as to be linearly displaceable in the transverse direction. Contrary movement of transverse sealing jaws 13a and 13b is realized by means of an eccentric mechanism. To this end, one eccentric element 14a and 14b per support bar 16 is mounted on drive shaft 04 so as to co-rotate therewith. In turn, a coupling element 15 which is connected to associated support bar 16 in a pivoting manner is mounted on each eccentric element 14a and 14b so as to rotate independently thereof. Thus, rotation 24 of drive shaft 04 and, simultaneously, of eccentric elements 14a and 14b can be translated into the alternating movement of respective support bars 16 and thus of transverse sealing jaws 13a and 13b.

(9) Together with coupling element 15 and support bar 16, eccentric elements 14a and 14b disposed on drive shaft 04 form a translation mechanism which translates rotation 24 of drive shaft 04 into an alternating contrary movement of transverse sealing jaws 13a and 13b. The translation mechanism with transverse sealing jaws 13a and 13b is part of transverse sealing unit 11. A drive motor 02 comprising a base 03a and a stator 03b is provided for driving drive shaft 04. Drive motor 02 is realized in the manner of a drive motor in which the actual position, namely rotation angle φ, and actual torque M can be measured using a corresponding drive controller, which is not shown in FIG. 1.

(10) FIG. 2 shows a diagram relating to the recording of target positions, namely target rotation angles φ, each associated with a target torque M. To record the corresponding values of target rotation angles φ1 to φ6, the entire tubular bag machine including transverse sealing unit 01 is first calibrated and film tube 09 is removed from between transverse sealing jaws 13a and 13b. Then, the drive control system sets target torques M1, M2, M3, M4, M5 and M6, one after the other, for transverse sealing unit 01. Each time respective torque values M1 to M6 have been reached, actual rotation angle φ is determined by the position sensor system and determined actual rotation angle φ is stored in the drive control system as target rotation angle φ1 to φ6. As a result, a target rotation angle φ1 to φ6 is stored for each target torque M1 to M6 at the end of said determination process, the target torques and target rotation angles each forming value pairs. As illustrated in FIG. 2 in a schematic and exemplary manner, the value pairs displayed in the torque/rotation angle diagram all lie on one straight line. It is the slope of said straight line that represents the spring stiffness of the translation between the drive motor 02 and the transverse sealing jaws 13a and 13b.

(11) FIG. 3 shows the diagram according to FIG. 2 with the addition of two tolerance thresholds 30 and 31. The two tolerance thresholds form a corridor around the straight line through the value pairs of target torques M1 to M6 and target rotation angles φ1 to φ6.

(12) The diagram illustrated in FIG. 4 shows the diagram according to FIG. 3 after a first function test has been performed. In this function test, film tube 02 is again removed from between transverse sealing jaws 13a and 13b and the transverse sealing jaws are closed. Then, target torques M1 to M6 are output by drive motor 02 one after the other and the resulting actual rotation angle of drive motor 02 is measured each time. Corresponding value pairs 32 are marked by a circle in FIG. 4. As can be seen, the six value pairs 32 resulting during the function test all lie on a straight line that is shifted upward parallel to the straight line running through value pairs 33 composed of the target torque and the target rotation angle (see FIG. 3). This parallel shift of the spring line may be due to the fact that the installation of a new transverse sealing tool caused a slightly different distance between transverse sealing jaws 13a and 13b. However, since value pairs 32 are all located within the corridor between tolerance thresholds 30 and 31, no error has to be reported.

(13) FIG. 5 shows value pairs 34 of a second function test, which represents the actual position, namely the actual rotation angle, together with the respective target torque M1 to M6 produced. As can be seen, value pairs 34, too, all lie on one straight line, said straight line having a different slope than the straight line through value pairs 33 composed of the target torque and the target rotation angle. Said different slope of the spring line through value pairs 34 may be due, for example, to the installation of a stiffer component, such as a slightly stiffer transverse sealing tool. Since the upper three value pairs 34 are located outside of the corridor between tolerance thresholds 30 and 31, an error is reported in this case, so that operating personnel can perform an error diagnosis.