The present invention concerns an apparatus for handling and locally fixing flat thermoplastic materials, an arrangement of at least two apparatuses for handling and locally fixing flat thermoplastic materials, and a handling device for receiving, transporting and/or depositing at least one flat thermoplastic material.
To be able to make optimum use of the lightweight construction potential of fiber composite materials a load-optimized and waste-optimized arrangement of the reinforcing fibers in the component is indispensable. Additive manufacture—that is to say the successive “deposit” of material to provide a defined three-dimensional body—has proven to be a processing procedure which is highly suited to the material involved, precisely in the field of fiber composite materials. The “deposit” of material, especially flat thermoplastic materials, can be implemented for example by the so-called pick-and-place method. In that method, flat thermoplastic materials, preferably with a fiber reinforcement, particularly preferably with a unidirectional fiber reinforcement, are received by handling devices from a storage means or magazine, transported to a previously defined deposit position, and deposited there. Such a handling device comprises a motion unit like for example an articulated arm robot and an end effector, which, depending on the flat thermoplastic materials to be handled, can be equipped with clamping, needle, suction grippers or the like. Suction grippers, also referred to as vacuum handling devices, are described for example by DE 20 2013 009294 U1 or DE 10 2009 047916 B4. In that case, depending on the requirements involved, different operative principles are used for generating the vacuum (Coanda, venturi or Bernoulli principle). Such gripping systems have become increasingly adopted for handling thin flat materials as they hold the flat thermoplastic material securely in position without it being damaged in that case—as occurs in the case of needle grippers.
Further suction grippers known from the state of the art are disclosed in DE 4127133 A1, EP 0 397 029 A2, DE 20 2012 101 859 U1 and in DE 2 535 460 A1, wherein these devices are provided with temperature control units in order to adjust the gripper to a temperature of the material to be gripped. From WO 2010/073514 A1 an electrostatic gripper comprising such a temperature control unit is known. This temperature control of the gripper is to avoid damages to the material to be gripped due to thermal stress or to the formation of condensate between the gripper and the material to be gripped.
After the flat thermoplastic material to be processed has been placed at its predetermined location by the handling device it has to be secured against slipping in some fashion for further processing. In the case of thermoplastic materials, that is generally achieved by means of a material-bonded connection between the substrate which has already been deposited—also referred to hereinafter as the join partner—and the flat thermoplastic material deposited thereon. The fusibility of the flat thermoplastic material is utilized for making the connection. The energy necessary for that purpose can be supplied by a heating element, for example with a resistance heating means or by an ultrasonic sonotrode. The two components (flat thermoplastic material and join partner) are pressed against each other and welded together.
The thermal contact or the thermal pulse welding method is in the packaging industry a well-established method of welding thin films with a fast cycle time. As film-like semi-finished articles (flat thermoplastic materials) are also processed using the pick-and-place method those welding methods are suitable for making a material-bonded connection between the join partner and the thermoplastic material. For that purpose use is generally made of electrically heatable heating elements which exert a pressure immediately after positioning of the semi-finished article on the flat thermoplastic material and connect the flat thermoplastic material to the join partner by the supply of heat.
Another known configuration in the state of the art provides that a heating element is mounted to the holding device which can be applied with a holding region for exerting a holding force against a surface of the flat thermoplastic material, the heating element being thus mounted separately from that holding unit, wherein a welding operation can be carried out after positioning by the heating element. For mounting the two components on the end effector however it is necessary for same to be adapted to the geometry of the flat thermoplastic material to be handled. That however results in an increased requirement for adaptation upon any change in the geometry of the flat thermoplastic material as a fresh position has to be selected both for the holding element and also for the heating element. In addition a specific fixing is to be provided on the end effector both for the holding element and also for the heating element, and that is disadvantageous in regard to saving weight and the agility involved therewith of the entire system.
Thus an increased amount of structural space is necessary for the arrangement of the holding element and the heating element. That limits on the one hand the maximum number of holding elements and/or heating elements which can be disposed on an end effector, while on the other hand it increases the minimum handleable size for the flat thermoplastic materials.
In addition the deposit accuracy which can be achieved in respect of a flat thermoplastic material suffers by virtue of the above-mentioned arrangement of the two elements. In the case of larger spacings between the holding and the heating elements, there is an increased probability that the fixing position of the flat thermoplastic material differs from the target position by virtue of the non-existent guidance. As a result gases or also overlaps can occur, which represent a weak point in the subsequent component.
By virtue of the fact that, in the state of the art, the heating element comes into contact only immediately after attainment of the final position of the flat thermoplastic material in order to weld same, very high heating temperatures are necessary for short welding times so that the flat thermoplastic material to be deposited can be rapidly completely fused over its entire thickness and thus welding to the join partner can be achieved.
The object of the invention is to provide an apparatus for handling and locally fixing flat thermoplastic materials, an arrangement of at least two apparatuses for handling and locally fixing flat thermoplastic materials, and a handling device, in which an improvement is at least partially achieved over the above-mentioned disadvantages in the state of the art.
The above object is attained by an apparatus in which, arranged within or surrounded by a holding region of at least one holding device, is at least one heating element by which the flat thermoplastic material can be locally thermally fixed to a join partner within or surrounded by the holding region of the at least one holding device.
Thus, in a variant by way of example, the heating element can be integrated into the holding device, more precisely into the holding region. Introduction of the necessary heating energy can be effected electrically or inductively. A structure having a heating means using hot gas is also certainly conceivable. Structures with an ultrasonic sonotrode are equally conceivable.
According to the invention, it is therefore provided that the at least one heating element is arranged within a holding region or surrounded by a holding region. In other words, the heating element is integrated into the holding element and thus the function of handling and local thermal fixing can be combined in one installation component by virtue of the apparatus according to the invention.
This therefore provides a compact apparatus for handling and thermal fixing, which requires a small amount of space and is of a low weight in comparison with the above-mentioned configurations in the state of the art. Accordingly the weight and thus the inertia of the overall handling system is reduced, which in turn contributes to enhancing flexibility and agility.
In addition, the apparatus according to the invention makes it possible to handle substantially smaller flat thermoplastic materials in comparison with the structures known in the state of the art. As the heating element is now arranged within or surrounded by the holding region the minimum size of a flat thermoplastic material is only still limited to the size of the holding region.
A further substantial advantage of the apparatus according to the invention is that it ensures a high level of deposit accuracy. By virtue of the integration of the heating element into the holding region, the flat thermoplastic material is thermally fixed precisely where it is held by the holding region. It is possible in that way to effectively counteract displacement of the flat thermoplastic material by virtue of the welding operation and formation linked thereto of gases or overlaps of the flat thermoplastic material.
Preferably, the flat thermoplastic material can be locally thermally fixed to the join partner in a state held by the at least one holding device. In this connection, it can be provided that the flat thermoplastic material is held by a holding force to the holding device while the flat thermoplastic material can be locally thermally fixed to the join partner without an additional pressure force occurring between the flat thermoplastic material and the join partner.
However, the flat thermoplastic material, in a state of being held by the at least one holding device, can be already locally heated before being placed on the join partner. In that case, heating at the holding device can already begin upon being received, immediately after being received, or at any point in time during transport to the join partner. The flat thermoplastic material can be heated upon reaching the join partner but still in the solid-body state, or selectively also when already in the melted state. The possibility of bringing forward the commencement of heating in that way means that the heating element can be operated at a lower temperature. That has a positive effect on the longevity of the apparatus and results in a lower level of thermal loading on the flat thermoplastic material.
Furthermore, the at least one heating element can connected to the at least one holding device moveably—preferably by a spring element. Thus, for example, a heating element can be so mounted to the holding device that, during a handling operation, the heating element remains in a retracted state and it is only when local thermal fixing of the flat thermoplastic material is required by the heating element that the heating element is moved to the thermoplastic material. That configuration makes it possible to leave the heating element in a heated state and to alter the thermal energy which is transmitted to the flat thermoplastic material only by a displacement of the heating element. Thus it can preferably be provided that the flat thermoplastic material is heatable continuously or in interval mode by the at least one heating element.
Particularly preferably, an insulating layer can be provided at least region-wise between the at least one heating element and the at least one holding device. The holding device can be protected from thermal energy from the at least one heating element by that insulating layer, and possible damage to the holding device by that thermal energy can be avoided.
In a further embodiment, the at least one holding device can be in the form of an electrostatic gripper, and an electrostatic charge of a contact surface of the electrostatic gripper can be applied or changed by at least one activation device.
Alternatively, however, the at least one holding device can be in the form of a vacuum suction gripper. Furthermore, the at least one heating element can be arranged in a suction region of the vacuum suction gripper and/or the vacuum suction gripper has a suction device, wherein a reduced pressure can be produced in a suction region of the vacuum suction gripper by the suction device. That suction device can be implemented for example on the basis of the Coanda, venturi or Bernoulli principle.
Furthermore, an arrangement can include at least two apparatuses according to the invention for handling and locally fixing flat thermoplastic materials, with the at least two apparatuses being connected together by a carrier structure. Such a carrier structure in that respect can have a one-part or multi-part configuration. Preferably, the at least two apparatuses are arranged so that at least one flat thermoplastic material can be held at one side in unilateral contacting relationship along a surface by the at least two holding devices.
Particularly preferably, an open-loop or closed-loop control unit is provide, wherein each apparatus (or when there are more than two apparatuses a group of apparatuses) can be selectively open-loop or closed-loop controlled by the open-loop or closed-loop control unit. At least one holding device can be selectively open-loop or closed-loop controlled and/or at least one heating element can be selectively open-loop or closed-loop controlled by the open-loop or closed-loop control unit. Accordingly, a group or a single apparatus can be actuated individually, more precisely the heating element or the holding function of the individual apparatus or apparatuses. Such a configuration makes it possible, in the case of an arrangement of a plurality of apparatuses, to actuate only the apparatuses which are required for handling or thermal fixing of a certain flat thermoplastic material. Accordingly there is a high degree of flexibility in respect of the external contour of a flat thermoplastic material, in respect of the handling or local fixing of which only the apparatuses which are required are used while the remaining apparatuses of the arrangement are put into a non-active operating state.
In addition protection is claimed for a handling device for picking up, transporting or depositing at least one flat thermoplastic material comprising at least one apparatus according to the invention and/or an arrangement according to the invention.
Further details and advantages of the present invention are described more fully hereinafter by means of the specific description with reference to the embodiments by way of example illustrated in the Figures in which:
In addition in the
In contrast to the preceding variants the configuration shown in
It can further be provided that an arrangement as shown in
It can however also be provided that, in the case of an arrangement as shown in
Thus in a first method step as shown in
Subsequently (shown in
In a next method step (see
In a following method step (
In a last step in the method (shown in
It is however now also possible by means of an embodiment of the apparatus 13 according to the invention to apply a flat thermoplastic material 3 to a further flat thermoplastic material 3, fuse it, and then lift both flat thermoplastic materials 3, as shown in
In a last method step the first flat thermoplastic material 3 can be lifted again by the apparatus 13, now being connected to its join partner 5—the second flat thermoplastic material 3—and thus that can also be lifted out of the magazine 27.
Number | Date | Country | Kind |
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A 50380/2018 | May 2018 | AT | national |