Method for operating a blow-moulding machine
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- KHS GMBH
- Filing Date
- 2024-05-17
- Publication Date
- 2026-05-06
AI Technical Summary
The existing methods for changing blow molds in blow molding machines are complex and impractical, especially when dealing with a large number of molds, as they require manual or automated adjustment of position coordinates which can deviate slightly from their target positions, necessitating a cumbersome process to ensure precise gripping and positioning.
A method that involves an initialization process where the gripper of a changing robot determines and stores the position coordinates of storage and mold positions using a detection device, allowing the robot to move accurately into these positions during the changing process, with the aid of a force measuring device to ensure precise alignment along a guide direction, simplifying the setup and operation of container treatment systems.
This method simplifies and optimizes the setup of container treatment systems by allowing for precise and efficient positioning of blow molds and base molds, reducing the complexity of changing processes and enabling automated operation with high accuracy, thus improving the overall efficiency of the blow molding machine.
Smart Images
Figure EP2024063691_02012025_PF_FP_ABST
Abstract
Description
[0001] Method for operating a blow molding machine
[0002] Description:
[0003] The present invention relates to a method for position adjustment between a gripper of a changing robot of a container treatment plant, in particular a blow molding machine, and a treatment part to be gripped.
[0004] Such container treatment systems are generally known from the prior art, although the invention preferably refers to blow molding machines, particularly for the production of beverage containers. These beverage containers can, for example, be beverage bottles made of a thermoplastic, in particular polyethylene terephthalate (PET).
[0005] For blow molding, preforms are typically first prepared and heated in a heating device. The heating causes the preform material to soften, making them easier to deform when exposed to a fluid. The actual forming then takes place in the blow molding machine. The blow molding machine has at least one mold, which forms a blow cavity with a contour corresponding to the shape of the container or beverage bottle to be produced.
[0006] Accordingly, the blow mold determines both the size and shape of the containers to be produced, and a changeover is required if different types of containers are to be manufactured. Changing the blow molds is usually done by removing the molds from a first set located in the blow molding machine and placing them in a storage device. Blow molds from a second set can then be removed from this or another storage device and inserted into the blow molding machine. The changeover can generally be done manually. However, it is now also common practice to perform the changeover automatically using changing robots.
[0007] Such a design is disclosed, for example, in DE 102017 120 774 A1 and EP 2 878 425 B1. Here, the changing robot uses a gripper to automatically approach the blow molds in the storage device or the blow molding machine and grip them to effect a change of the blow molds within the blow molding machine.
[0008] For such an automated changeover, it is necessary for the changeover robot to know the individual position coordinates of storage positions, for example, in the storage facility, so that it can easily grip the blow molds during the changeover process. In this context, the storage position refers to a position to which the changeover robot must move with its gripper in order to grasp the blow mold.
[0009] In principle, the storage positions of the blow molds are predetermined and, for example, determined by the design of the storage device. However, practice has also shown that the individual storage positions can deviate slightly from their target position, meaning that the changing robot must be moved to the deviating position coordinates. In practice, this is usually achieved by adjusting the position coordinates in the control device until the exact storage position is reached. However, this process is complex and impractical, especially when there are a large number of blow molds. Although the example refers specifically to blow molding machines, this problem also arises in other container processing systems that are equipped with other processing components instead of blow molds.
[0010] The invention is based on the object of providing a method which simplifies and optimises the setting up of a container treatment plant.
[0011] The subject matter of the invention is a method according to claim 1. Accordingly, in an initialization process, a gripper, in particular a first gripper, of the changeover robot is successively guided into a storage position of a plurality of treatment parts, and the position coordinates of the storage position are stored in a control device. Subsequently, in a changeover process, the changeover robot moves the gripper to at least one of the storage positions based on the position coordinates.
[0012] Accordingly, the invention provides that the actual changeover process, in which the treatment parts are exchanged, is preceded by an initialization process in which the storage positions of the treatment parts are determined. For this purpose, the gripper of the changeover robot is moved to the storage position. After reaching the storage position, the position coordinates are then recorded by a recording device and stored in the control device. Accordingly, the position coordinates of the individual storage positions can be determined sequentially.
[0013] In this context, a particularly preferred embodiment is one in which the treatment parts are arranged in the storage position in a common storage device outside the container treatment system. Such storage devices are accordingly a type of storage magazine, in which the treatment parts can be stored together outside the container treatment system. The gripper then moves to the individual storage positions, and the position coordinates are determined. During the initialization process, the individual treatment parts are preferably not gripped while the storage positions are being recorded.
[0014] According to a further development of the method, during the initialization process, the gripper is successively guided into a molding position of a plurality of treatment parts in the container treatment system, and the position coordinates of the molding positions are stored in the control device. This molding position is the position assumed by the treatment part within the container treatment system. Accordingly, the changeover robot effects a transfer between the storage position and the molding position. Subsequently, during the changeover process, the changeover robot moves the gripper to at least one of the molding positions based on the position coordinates.
[0015] According to such an embodiment, the initialization process thus comprises at least two steps: in a first step, the position coordinates of the supply positions are determined, and in a second step, the position coordinates of the mold positions are determined and stored in the control device. The two steps can generally be performed sequentially. Alternatively, it is also conceivable to perform both steps alternately, so that a supply position is determined first, followed by a mold position of a treatment part.
[0016] According to a preferred embodiment of the method, the changeover robot initially moves the gripper into a pre-position during the initialization process. From this pre-position, the gripper is then moved into the storage position or the molding position by a substantially rectilinear movement along a guide direction. In this context, a substantially rectilinear movement means that a deviation transverse to the guide direction is preferably less than 5 mm, in particular less than 2 mm.
[0017] According to a particularly preferred development of the invention, the changing robot has a force measuring device, wherein the position coordinates of the storage position and / or the mold position are stored as soon as the force measuring device detects no force transverse to the guide direction - whereby "no force" in the sense of the invention also includes a reduced force that is less than or equal to a predetermined permissible force. According to such an embodiment, gripping is carried out using the gripper solely by movement along a guide direction. Thus, if no more forces (or only forces that are less than or equal to defined small forces) are detected transverse to the guide direction, it can be concluded that adjustment of the position of the corresponding gripper is no longer necessary.Consequently, the gripper is already in a position in which movement in the guide direction alone is sufficient to grip the part to be treated. Using such a force measuring device, it is thus possible to record the position coordinates in such a way that the storage position or the forming position is reached as soon as the gripper subsequently requires exclusive movement in the guide direction. In addition, a force along the guide direction can also be recorded. This makes it possible, for example, to detect a stop of the gripper on the part to be treated. The force measuring device can preferably be a load cell. Furthermore, it is provided that the force measuring device preferably detects a force in all three spatial directions. Of course, it is also sufficient if only forces transverse to the guide direction are recorded.
[0018] Preferably, during the initialization process, a second gripper of the changeover robot is successively guided into a storage position of a plurality of treatment parts, and the position coordinates of the storage positions are stored in the control device. Subsequently, during the changeover process, the changeover robot moves the second gripper into at least one storage position based on the position coordinates. Such a configuration is particularly advantageous when different types of treatment parts are to be grasped by the at least two grippers.
[0019] Accordingly, in the initialization process, the second gripper can then be successively guided into a molding position of a plurality of treatment parts in the container treatment system and the position coordinates of the molding position can be stored in the control device, and subsequently, in a changeover process, the changeover robot moves the second gripper into at least one molding position based on the position coordinates.
[0020] Preferably, the grippers are guided into the storage positions and / or the forming positions via guide pins arranged parallel to the guide direction on the treatment parts. Accordingly, the guide pins exert a force transverse to the guide direction if the first or second gripper is not precisely positioned. At the same time, the guide pins ensure that the grippers can be guided into the storage position or into the treatment parts, whereby, upon reaching these positions, preferably no force transverse to the guide direction acts on the force measuring device.
[0021] The container treatment plant is preferably a blow-molding machine and has a plurality of magazine positions arranged in the circumferential direction on a rotatably driven blowing wheel for receiving treatment parts that are at least partially designed as blow molds, and wherein all magazine positions are occupied by a blow mold in order to determine the position coordinates of the mold positions in the initialization process.
[0022] Accordingly, the position of the magazine locations also defines the position coordinates of the mold positions. To determine the position coordinates of the mold positions during the initialization process, all magazine locations are preferably occupied by a blow mold. This makes it possible to determine the position coordinates of the supply positions one after the other. The position coordinates are determined in such a way that the gripper is guided into the mold position here as well. However, gripping the blow mold is preferably not performed.
[0023] A further development of the invention further provides that after determining the position coordinates of a mold position in the initialization process, the blowing wheel is rotated by an angular position. The invention is based on the knowledge that the changing robot is usually arranged at a substantially fixed position on the circumference of the blowing wheel. In order to be able to arrange the blow molds in all magazine locations or remove them from a magazine location during the changing process, a certain rotation of the blowing wheel is always required between two change steps. This rotation is now also necessary to determine the individual mold positions. The angular position required for the rotation depends essentially on the number of magazine locations. The usual number of magazine locations is between 6 and 36. Accordingly, the angular position is an angle between 60° and 10°.
[0024] A preferred embodiment of the invention provides that each blow mold is formed from at least two blow mold halves, which are arranged so as to be pivotable relative to one another within the blow molding machine. Such a configuration makes it possible for the preforms to be inserted easily and for the blow mold to then be closed. Accordingly, it is fundamentally sufficient within the scope of the invention if only one blow mold formed from two blow mold halves is provided per magazine location. According to a further development, however, it is provided that a base mold is also arranged at each magazine location, so that the entire blow cavity required for blow molding is formed by the blow mold and the base mold. The base molds are usually inserted via the second gripper, with the first gripper consequently being provided for inserting the blow molds and the second gripper for inserting the base molds.
[0025] During the initialization process, the second gripper of the changing robot is then guided into a storage position of a plurality of base molds, and the position coordinates of the storage positions are stored in the control device. Subsequently, during the changing process, the changing robot moves the second gripper into at least one of the storage positions based on the position coordinates. Consequently, not only the position coordinates of the storage positions of the blow molds but also the position coordinates of the storage positions of the base molds are recorded. This preferably occurs after recording the storage data of the blow molds and particularly preferably also after recording the position coordinates of the mold positions of the blow molds.
[0026] Subsequently, in the initialization process, the second gripper is successively guided into a mold position of a plurality of base molds, and the position coordinates of the mold position are stored in the control device. Subsequently, in the changeover process, the changeover robot moves the second gripper to at least one of the mold positions based on the position coordinates.
[0027] In this context, a particularly preferred embodiment provides that the individual blow molds are removed from the magazine positions of the blowing wheel in advance in order to record the mold positions.
[0028] After completion of the initialization process, the actual changeover process can begin, wherein in the changeover process the first gripper grips a treatment part, in particular a blow mold, in the storage position and places it in the molding position in the corresponding magazine location or wherein in the molding position in the corresponding magazine location the treatment part, in particular a blow mold, is gripped by the first gripper and placed in the storage position.
[0029] Likewise, during the changeover process, the second gripper can also grip the treatment part, in particular a base mold, in the storage position and deposit it in the corresponding magazine location in the molding position. Alternatively, the second gripper can grip the treatment part, in particular a base mold, in the molding position in the corresponding magazine location and deposit it in the storage position. The invention further relates to a container treatment system according to claim 12, in particular a blow molding machine for blow molding, in particular for stretch blow molding, of containers and an associated changing robot, wherein the changing robot is associated with a control device configured to carry out the method according to the invention.
[0030] The changeover robot preferably has a force measuring device for detecting forces at least transverse to the guide direction, wherein the force measuring device can be connected to the control device via a signal connection, in particular wired or wireless. The force measuring device can also detect a force along the guide direction. This makes it possible, for example, to detect an attachment point.
[0031] Preferably, the treatment plant is a blow molding machine with a rotatably driven blowing wheel, which has a plurality of magazine positions arranged in the circumferential direction.
[0032] Preferably, the blow molding machine and the changing robot have a common control direction.
[0033] The invention is explained in more detail below using exemplary embodiments. They show:
[0034] Figure 1 shows a gripper which is not transferred to a storage position or forming position,
[0035] Figure 2 shows a gripper transferred to a storage position or forming position.
[0036] Figure 1 shows a blow mold 1 and a changing robot 2 with a first gripper 3, which is configured to grip the blow mold 1 by means of a gripping device 4. This makes it possible to insert the blow mold 1 into a blow molding machine or to remove the blow mold from this blow molding machine.
[0037] With the help of the changing robot 2, it is thus possible to effect an automated change of the blow molds 1. However, for this purpose, the required storage positions and / or mold positions of the blow mold 1 within a storage device and the blow molding machine must also be known.
[0038] For this purpose, the position coordinates of the stock position and the mold position are determined within an initialization process, whereby the positions are determined in an analogous manner.
[0039] For this purpose, as shown in Figure 1, the gripper 3 is brought toward the blow mold 1. However, as shown in Figure 1, there is an offset between the guide pins 5 of the blow mold 1 and the recesses 6 assigned to the gripper 3 with respect to a vertical direction V. Accordingly, a force in the vertical direction V acts on the gripper 3, which is detected by a force measuring device 7 designed as a load cell. Due to the detection of a force in the vertical direction V, a repositioning of the gripper 3 is necessary.
[0040] This repositioning can be effected solely by the design of the guide pins 5, which move the gripper 3 into the storage position or the molding position according to Figure 2, wherein in the example shown, no force component is then detected in the vertical direction V. Rather, the gripper 3 can be moved into the storage position, in which the gripping device 4 grips the blow mold 1, solely by movement in a guide direction F which is perpendicular to the vertical direction V. After this storage position has been reached, the position data can be transmitted to the control device 8, wherein transmission is already possible as soon as the force measuring device 7 no longer detects a force transverse to the guide direction F.
[0041] Using this method, the supply positions of the blow mold 1 and then the mold positions of the blow mold 1 are typically first recorded and transmitted to the control device 8. The same process can then also be used for the base molds, whereby the supply positions or the mold positions of the blow molds 1 and the base molds are determined independently of each other.
[0042] Based on the position coordinates stored in the control device 8, it is then possible to control the gripper 3 exactly according to the stored position coordinates and to effect a change of the blow molds 1 or the base molds.
[0043] List of reference symbols
[0044] 1 blow mold
[0045] 2 change robots 3 grippers
[0046] 4 gripping device
[0047] 5 guide pins
[0048] 6 recesses
[0049] 7 Force measuring device 8 Control device
[0050] F Guide direction
[0051] V vertical direction
Claims
Patent claims:
1. Method for position comparison between a gripper (3) of a changing robot of a container treatment plant, in particular a blow molding machine, and a treatment part to be gripped, wherein in an initialization process the gripper (3) of the changing robot (2) is guided one after the other into a storage position of a plurality of treatment parts (1) and the position coordinates of the storage positions are stored in a control device (8) and wherein subsequently in a changing process the changing robot (2) moves the gripper (3) into at least one storage position on the basis of the position coordinates.
2. Method according to claim 1, wherein the treatment parts in the storage position are arranged in a common storage facility outside the container treatment plant.
3. Method according to one of the preceding claims, wherein in the initialization process the gripper (3) is successively guided into a molding position of a plurality of treatment parts in the blow molding machine and the position coordinates of the molding position are stored in a control device (8) and wherein subsequently in the changing process the changing robot (2) moves the gripper (3) into at least one molding position on the basis of the position coordinates.
4. Method according to one of the preceding claims, wherein the changing robot (2) first moves the gripper (3) during the initialization process into a pre-position, from which the gripper (3) is then moved by a substantially rectilinear movement along a guide direction into the storage position or into the forming position.
5. Method according to one of the preceding claims, wherein the changing robot (2) has a force measuring device (7), wherein the position coordinates of the storage position and / or the mold position are stored as soon as the force measuring device (7) detects no force transverse to the guide direction.
6. Method according to one of the preceding claims, wherein in the initialization process a second gripper (3) of the changing robot (2) is successively guided into a storage position of a plurality of treatment parts and the position coordinates of the storage positions are stored in the control device (8) and wherein subsequently in the changing process the changing robot (2) moves the second gripper (3) into at least one storage position on the basis of the position coordinates.
7. Method according to one of the preceding claims, wherein in the initialization process the second gripper (3) is successively guided into a forming position of a plurality of treatment parts in the container treatment plant and the position coordinates of the forming position are stored in the control device (8) and wherein subsequently in a changing process the changing robot (2) moves the second gripper (3) into at least one forming position on the basis of the position coordinates.
8. Method according to one of the preceding claims, wherein the grippers (3) are each guided into the storage positions and / or the forming positions via guide pins (5) arranged parallel to the guide direction on the treatment parts.
9. Method according to one of the preceding claims, wherein the container treatment plant is a blow molding machine and a plurality of Has magazine locations arranged in the circumferential direction on a rotatably drivable blowing wheel for receiving treatment parts designed at least partially as blow molds (1), and wherein all magazine locations are occupied with a blow mold (1) in order to determine the position coordinates of the mold positions in the initialization process.
10. The method according to claim 9, wherein after determining the position coordinates of a mold position in the initialization process, the blowing wheel is rotated by an angular position.
11. Method according to claim 9 or 10, wherein in the changing process the gripper (3) grips a blow mould (1) in the storage position and places it in the moulding position in the corresponding magazine location of the blowing wheel or grips a blow mould (1) in the moulding position in the corresponding magazine location of the blowing wheel and places it in the storage position.
12. Method according to one of the preceding claims, wherein in the changeover process the second gripper (3) grips a treatment part designed as a base mold in the storage position and places it in the molding position in the corresponding magazine location of the blowing wheel or grips a base mold in the molding position in the corresponding magazine location of the blowing wheel and places it in the storage position.
13. Container treatment system for treating containers, in particular beverage containers, and an associated changing robot (2), wherein the changing robot (2) is associated with a control device (8) which is configured to carry out the method according to one of the preceding claims.
14. Container treatment plant according to claim 13, wherein the changing robot has a force measuring device (7) at least for detecting forces transverse to the guide direction, wherein the force measuring device can be connected to the control device via a signal connection.
15. Container treatment plant according to claim 13 or 14, wherein the treatment plant is a blow molding machine having a rotatably driven blowing wheel with a plurality of magazine locations arranged in the circumferential direction.
16. A container treatment system according to one of claims 13 to 15, wherein the blow-molding machine and the changing robot (2) have a common control device (8).
17. A container treatment arrangement with a container treatment system according to one of claims 13 to 16, wherein a treatment part is arranged on the gripper (3).