Application device having refilling cassette

Abstract

The invention relates to an application device (10) for applying adhesive elements (12a, 12b), comprising: a) a cassette unit (14) comprising: a1) a guide arrangement which comprises a supply roller (16) and a receiving roller (18); a2) an issuing region which has a dispensing edge (20); a3) a material strip (22) which comprises a number of adhesive elements (12a, 13b), wherein the adhesive elements (12a, 12b) are arranged with the adhesive layer on a strip-like separating material, wherein the cassette unit (14) is designed so that the material strip (22) provided on the supply roller (16) can be guided via the dispensing edge (20) to the receiving roller (18) such that the adhesive elements (12a, 12b) are separated from the separating material in the issuing region and are issued from the cassette unit (14); and b) a base unit (24) comprising: b1) a cassette receptacle; b2) a conveyor element (26) which has an adhesion-reduced surface; and b3) an application element (28), wherein the base unit (24) is designed to receive an adhesive element (12a, 12b) arranged on the conveyor element (26) using the application element (28) and to apply it to a substrate to be glued, wherein the application device (10) is designed so that an adhesive element (12a, 12b) issued from the cassette unit (14) is transferred with the adhesive layer to the adhesion-reduced surface of the conveyor element (26).

Description

[0001]Norderstedt, September 29, 2023 Our reference: 2022037 / PCT Official file number: New application Applicant: tesa SE Hugo-Kirchberg-Straße 1 22848 Norderstedt Application device with refill cassette Description The invention relates to an application device for applying adhesive elements to substrates to be bonded, a cassette unit and a base unit for a corresponding application device, and a method for applying adhesive elements to substrates to be bonded using a corresponding application device. Furthermore, a method for feeding a corresponding application device is disclosed. The use of adhesive elements is an important component of many modern manufacturing processes today. Corresponding adhesive elements are used not only for attaching components to a substrate,but also serve, in particular, to close openings in a substrate. Such openings are usually due to manufacturing processes and represent potential weak points in the final product through which, for example, moisture or contaminants can penetrate. The use of suitable, usually single-sided adhesive elements to close corresponding openings in substrates represents a simple, time- and cost-efficient solution for closing corresponding openings and preventing unwanted penetration of contaminants. In the state of the art, such adhesive elements are already regularly used for this purpose, which are also referred to as die-cuts due to their manufacturing process. In principle, it is conceivableto manually place the corresponding adhesive elements on a substrate. However, due to the increasing automation and the continued interest in a process that is as error-free and efficient as possible, automated application devices have been developed that serve to apply adhesive elements to a substrate to be bonded. A wide range of requirements are placed on corresponding application devices. In particular, corresponding application devices must enable a reliable and reproducible application of adhesive elements to the substrates, with a high throughput being desirable. One group of application devices known from the prior art relies on the fact that in a separate,Adhesive elements provided by a dispenser arrangement spaced apart from the application device are picked up by the application device and placed on the substrate. However, this design is often perceived as disadvantageous, as it generally requires a lot of installation space and usually requires a relatively extensive movement of the application elements when they are moved back and forth between the dispenser unit and the substrate to be bonded, which is often perceived as inefficient. Correspondingly long guide paths increase the risk of incorrect placement, for example, due to slipping on the application element, and of contamination on the adhesive element, which can result in undesirable deterioration of the achievable bond strength. Against this background, application devices with an integrated dispenser arrangement for adhesive elements were designed.in which the distances between the provision of the adhesive element and the application device are very short, so that both can be implemented, for example, as part of an end effector of a robot head. Among these application devices with an integrated dispenser for the adhesive elements, one of the greatest challenges is to reliably provide the adhesive elements, which are usually provided on a tape-like release liner from a roll, in such a way that they can be reliably picked up and precisely applied by the actual application element of the application device. This represents a major challenge in practice, particularly because a concept with refill cassettes should be used to supply corresponding application devices.to enable rapid filling of the application device with new adhesive elements. The desired reversible and non-destructive interchangeability of the reservoir of adhesive elements makes it difficult to appropriately present the adhesive elements provided on the strip-shaped separating layer to the actual application element, which themselves should not be part of the replaceable cassette. Accordingly, the implementation of an advantageous application device that can be loaded with adhesive elements via a refill cassette requires a suitable mechanism for the interaction between the cassette unit and the base unit supporting the application element. To solve this problem, a design was proposed that utilizes a so-called oscillating dispensing edge. The cassette comprises a movable element that can be moved out of and back into the cassette.The purpose is to guide the strip-like separating layer out of the cassette and thereby present the adhesive element arranged on the strip-like separating layer outside the cassette to an application element, so that the adhesive element can be picked up by this application element and ultimately applied to a substrate. Even if good results can be achieved in many cases with corresponding structures with a pendulum dispensing edge, the effort associated with implementation, particularly in the design of the refill cassette, is regularly perceived as disadvantageous. This requires not only an additional drive to move the pendulum dispensing edge, but in many cases also a very complex guide arrangement with numerous guide units, for example, guide rollers, some of which must also be designed as movable web tension elements.to compensate for the periodic deformation of the band-shaped release material caused by the oscillating dispensing edge. Accordingly, the effort associated with the production of such refill cassettes is relatively high, and in the case of used refill cassettes, a comparatively large amount of waste is generated unless they are refilled, which is difficult in many cases due to the complexity of the design. Due to the high complexity associated with corresponding structures with an oscillating dispensing edge, attempts were made to provide alternative solutions. An exemplary solution is disclosed in EP 3569534 A1. The approach of EP 3569534 A1 is not disclosed in connection with a solution based on a refill cassette and, in the inventors' opinion, is not optimally suited for this purpose. However, EP 3569534 A1 shows a solution without an oscillating dispensing edge.in which the die-cuts are instead transferred via a stationary dispensing edge to a revolving suction belt, with the adhesive surface facing outwards. Using a vacuum, the adhesive elements are held with the non-adhesive side on the suction belt and guided around it until they are at the tip of the suction belt, from where they are glued, for example, onto a hole. In this solution, the suction belt thus essentially represents the application element that is intended to provide the final attachment of the adhesive element to the substrate. Even though the solution disclosed in EP 3569534 A1 enables a simplification in the design of the dispenser arrangement compared to a pendulum dispensing edge, the inventors believe it is nevertheless associated with significant disadvantages that stand in the way of efficient implementation in a product with a replaceable refill cassette. In particular, it is perceived as disadvantageous thatthat the adhesive elements are held to the rotating suction belt exclusively by the suction function, so that, especially with a moving application device, a sufficient suction effect must always be ensured. This requires considerable equipment, for example, with regard to the perforation of the suction belt and the devices necessary for generating the negative pressure, such as pumps and hose systems. A corresponding design with suction belts cannot be dispensed with even in simple, stationary application devices, since, due to their design, application can only be carried out for those adhesive elements that are arranged on the side wall of the suction belt, for which a suction effect is always necessary. Furthermore, in the solution of EP 3569534 A1, the adhesive elements are not separated upon transfer to the actual application element.This is achieved by the circulating suction belt. This leads to a situation where, unless the distance between the adhesive elements on the strip-shaped release material is chosen to be uneconomically large, a large number of successively arranged die-cuts are suctioned onto the suction belt exposed for application purposes, the adhesive layer of which, however, already faces outwards and is thus exposed. As a result, the application element itself is essentially provided with a sticky surface, which is not only disadvantageous from a handling perspective, but also carries the risk that the exposed adhesive surfaces of the adhesive elements become contaminated with dust or other components before application, thus adversely affecting the achievable bond strength after application. A further disadvantage is sometimes perceived that, in order to ensure a continuous, error-free transfer of the adhesive elements from the dispensing edge to the circulating suction belt,the distance between these two elements must not change. However, since at the same time a construction effort comparable to the construction of a pendulum dispensing edge must be avoided, the arrangement of the dispensing edge relative to the die-cut roll must also be kept constant. However, if, as disclosed in EP 3569534 A1, the application is to be effected by pressing an adhesive element sucked onto the suction belt onto a substrate, but the suction belt, the dispensing edge, and the roll holder are rigid relative to each other, this means that in order to apply an adhesive element, both the suction belt, the dispensing edge, and the die-cut roll must be moved relative to the substrate. This therefore means that a relatively large block, i.e., for example, the entire end effector, must be moved completely for each application step, whereby in particular the die-cut roll, which usually weighs several kilograms, must be moved.This is an aspect that is often perceived as disadvantageous, particularly in light of increasing awareness of energy-efficient working. The primary objective of the present invention was to eliminate or at least reduce the above-described disadvantages of the prior art. In particular, the objective of the present invention was to provide an advantageous application device for applying adhesive elements to substrates to be bonded, which enables reliable, time- and cost-efficient application of adhesive elements. The application device to be specified should be capable of being implemented with a replaceable refill cassette and yet still ensure reliable delivery of adhesive elements from the refill cassette to the application element. It was an objective of the present invention that the application device to be specified should be operable with cassette units.which should be designed to be particularly simple in construction and, as a result, particularly time- and cost-efficient to manufacture. It was an object of the present invention that the application device to be specified should be suitable for the application of adhesive elements of different sizes without structural changes and, moreover, should allow the adhesive elements to be packed as tightly as possible on the material strip used for feeding, without adversely affecting the precision of the application. Furthermore, it was an object of the present invention that the application device to be specified should be operable with cassette units that are particularly suitable for refilling. It was a further object of the present invention that the application device to be specified should be operated as energy-efficiently as possible, ideally avoidingthat for the final application process, the cassette unit along with the material roll must also be moved. Furthermore, it was an object of the present invention that the application device to be specified should be executable in simple designs even without complex devices for generating a vacuum for the interim fixation of the adhesive elements, as is known, for example, from suction belts. In this respect, it was a supplementary object of the present invention that, insofar as a vacuum-based fixation is used, a secondary fastening mechanism should advantageously be provided that can at least partially compensate for any fluctuations in the strength of the vacuum-based fixation. Furthermore, it was an object of the present invention that the application device to be specified should guide the adhesive elements in such a way thatthat the adhesive layer intended for bonding to the substrate is protected from contamination for as long as possible. It was a further object of the present invention to provide a cassette unit for use in the application devices to be specified, as well as corresponding base units for the application devices to be specified. Furthermore, it was a further object of the present invention to provide a method for applying adhesive elements to substrates to be bonded using a specified application device. It was a secondary object of the present invention to further provide a method for feeding a specified application device. The inventors of the present invention have now found that the objects described above can be achieved if an application device for applying adhesive elements to substrates to be bonded is provided,in which the cassette unit is arranged in the cassette receptacle of a base unit, when the adhesive elements arranged on a material strip are guided in the cassette unit over a dispensing edge, so that they are separated from the release material and transferred with the adhesive layer downwards to a conveyor element of the base unit, which has a reduced-adhesion surface, so that the adhesive elements resting on the conveyor element with the adhesive layer can be picked up by an application element of the base unit from the conveyor element and applied to a substrate, as defined in the claims. The above-mentioned objects are thus achieved by the subject matter of the invention, as defined in the claims. Preferred embodiments of the invention emerge from the subclaims and the following explanations. Such embodiments, which are referred to below as preferred,are combined in particularly preferred embodiments with features of other embodiments designated as preferred. Combinations of two or more of the embodiments designated below as particularly preferred are therefore very particularly preferred. Likewise preferred are embodiments in which a feature of an embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred cassette units, base units and methods emerge from the features of preferred application devices. The invention relates to an application device for applying adhesive elements to substrates to be bonded, comprising: a) a cassette unit, comprising: a1) a guide arrangement comprising a feed roller and a take-up roller, a2) an output area with a dispensing edge,and a3) a material strip comprising a plurality of adhesive elements with a carrier layer and an adhesive layer connected thereto, wherein the adhesive elements with the adhesive layer are arranged on a web-shaped release material, wherein the cassette unit is configured such that the material strip provided on the feed roll can be guided over the dispensing edge to the take-up roll in such a way that the adhesive elements are separated from the release material in the dispensing area and dispensed from the cassette unit, b) a base unit comprising: b1) a cassette holder for receiving the cassette unit, b2) a conveyor element with an adhesion-reduced surface, and b3) an application element, wherein the base unit is configured to receive an adhesive element arranged on the conveyor element with the application element and to apply it to a substrate to be bonded,and wherein the cassette unit is arranged in the cassette holder in a reversible and non-destructively replaceable manner, wherein the application device is configured to transfer an adhesive element dispensed from the cassette unit with the adhesive layer onto the adhesion-reduced surface of the conveyor element, so that the transferred adhesive element with the application element can be picked up by the adhesion-reduced surface of the conveyor element and applied to a substrate to be bonded. The application device according to the invention serves to apply adhesive elements to substrates to be bonded, and is particularly suitable for the application of so-called die-cuts in the field of vehicle production. The application device according to the invention can be integrated into existing production lines in a variety of ways.in which adhesive elements must be applied to substrates. For example, a largely stationary application device is conceivable, in which, for example, only the application element picks up the adhesive elements provided from the cassette unit and places them on the substrate as part of a "pick & place" process. However, in the inventors' estimation, for the vast majority of cases, a configuration of the application device according to the invention will be preferred in which it is designed as a so-called end effector. In accordance with the expert understanding, an end effector is the executing and / or concluding element of automated movement units, for example, robot arms. In other words, end effectors in the field of robotics are the last components of a kinematic chain, which are usually configured to execute an execution instruction specified by an external control device.optionally together with the automated movement unit to which they are attached. Accordingly, an application device according to the invention is preferred, wherein the application device is an end effector for an automated movement unit, preferably a robot arm. Also preferred is an application device according to the invention, wherein the application device is arranged on an automated movement unit, preferably a robot arm. The person skilled in the art will understand that the application device according to the invention comprises a plurality of automated or automatable components, in particular for moving the conveyor element or the application element and for guiding the material strip over the dispensing edge, for example by driving the rollers in the cassette unit. In principle, it is possible for this control, for example together with the control of the automated movement unit,by an external control device. However, in the opinion of the inventors, it is advantageous if the application device according to the invention also comprises an internal electronic data processing device that can control one or more of these components. Thus, an application device according to the invention is preferred, wherein the application device comprises an electronic data processing device for controlling the application device, preferably as a component of the base unit. The application device according to the invention initially comprises a cassette unit, which can also be referred to as a refill cassette. The task of this cassette unit in the application device according to the invention is to provide the application element of the base unit with the adhesive elements to be applied, wherein the person skilled in the art understandsthat the cassette unit of the application device according to the invention and the base unit are designed such that the cassette unit can be inserted reversibly and non-destructively into the cassette receptacle of the base unit, which, according to the inventors' assessment, can be achieved in particular by a magnetic connection. Therefore, an application device according to the invention is preferred, wherein the cassette unit is arranged in the cassette receptacle via a magnetic connection mechanism so that it can be reversibly and non-destructively removed. In particularly preferred embodiments, wireless communication between the cassette unit and the base unit is possible, for example, by means of appropriate transmitter-receiver systems, in particular via RFID.to verify a successful connection between the cassette unit and the base unit. Advantageously, further data can also be exchanged via the wireless communication connection, for example, the dimensions of the adhesive elements guided in the cassette unit, so that, for example, an application element of the base unit suitable for the dimensions of the adhesive elements can be selected for the application, or the speed control of the conveyor element can be adapted to the desired separation effect. Accordingly, an application device according to the invention is preferred, wherein the application device comprises a wireless communication system, preferably an RFID system, whose electronic communication units are arranged in the cassette unit and the base unit, wherein the application device is configured to control the application device depending on operating parameters.which are provided by the cassette unit via the wireless communication system, wherein the wireless communication system preferably serves to check the presence of the cassette unit in the base unit and / or to send operating parameters of the cassette unit to the electronic data processing device of the application device. In the cassette unit, the individual adhesive elements are arranged as part of a material strip with their adhesive layer on a web-shaped release material, so that the carrier layer of the adhesive elements faces outwards. The adhesive elements are described in more detail below. At this point, however, the focus is initially on the structure of the cassette unit, i.e. the refill cassette. A central element of the cassette unit is the guide arrangement,in which the material strip is guided and which comprises a so-called feed roll and a take-up roll. In its unused state, the feed roll comprises the wound material strip on which the adhesive elements are arranged, whereas the take-up roll is intended to receive only the web-shaped release material after the adhesive elements have been separated from the web-shaped release material. In accordance with the expert's understanding, the web-shaped release material is thus successively unwound from the feed roll during implementation of the method according to the invention or during operation of the application device according to the invention, separated from the adhesive elements in the output area, and subsequently wound onto the take-up roll, so that a completely used cassette unit will in practice usually comprise a web-shaped release material.which, apart from any remainder still connected to the feed roll, is essentially completely wound onto the take-up roll. In other words, this is an application device according to the invention, wherein the cassette unit is configured to roll the web-shaped release material separated from the adhesive elements onto the take-up roll. Between unwinding from the feed roll and rolling onto the take-up roll, the material strip is guided over a dispensing edge, which takes place in a partial area of ​​the cassette unit, which is referred to as the output area in the context of the present invention. The concept of a dispensing edge is well known to those skilled in the art of adhesive technology. The material strip with the web-shaped release material and the adhesive elements arranged thereon is fed onto the dispensing edge,The web-shaped release material is guided sharply around the dispensing edge at the end of the dispensing edge. Due to the inherent stiffness of the adhesive element, which is greater than the adhesion to the web-shaped release material, the adhesive element cannot follow this movement of the release material and is instead successively detached from the release material the further the material strip is guided over the dispensing edge. The corresponding area of ​​the cassette unit is referred to here as the output area, because the adhesive element thus separated from the web-shaped release material is dispensed from the cassette unit at this point and transferred for further handling in the base unit, whereas the web-shaped release material, now freed from the adhesive element, is guided further towards the take-up roll and accordingly remains in the cassette unit. It can be seen as an advantage of the application device according to the invention thatthat it is very flexible with regard to the design of the dispensing edge, so that the person skilled in the art can resort to arrangements known from the prior art which fulfill the function of separating the adhesive element from the web-shaped release material. For example, an application device according to the invention is preferred, wherein the dispensing edge is a knife edge. To reduce possible friction losses and consequently to reduce the required motor power, it is preferred to use a rounded dispensing edge. Additionally or alternatively, an application device according to the invention is preferred, wherein the cassette unit is configured to guide the material strip provided on the feed roll over the dispensing edge in such a way that the web-shaped release material is deflected by 90° or more at the end of the dispensing edge. The person skilled in the art understands,that the actual deflection angle in practice will depend on the design of the dispensing edge, so that, for example, deflection angles of 150° or more can be achieved. However, the person skilled in the art will understand that, with a view to advantageously avoiding a swinging dispensing edge and the associated structural design, a design in which the dispensing edge is essentially fixed in position is particularly preferred, since this allows particularly simple structures to be achieved that advantageously fully fulfill the functionality. Thus, for essentially all designs, an application device according to the invention is particularly preferred, wherein the dispensing edge is immobile in the cassette unit and / or wherein the dispensing edge is arranged in a fixed position in the cassette unit. In light of the above explanations, it is clear to the person skilled in the art,that the material strip initially provided on the feed roll must be guided along the dispensing edge or over the dispensing edge towards the take-up roll. For this purpose, it is fundamentally conceivable to provide a separate drive unit in the cassette unit, which can drive the feed roll and / or the take-up roll to enable the desired guidance of the material strip. However, the inventors propose that such an equipment of the cassette unit with a drive unit, particularly considering the energy sources required for this, can lead to a significant increase in the design effort for the cassette units, which adversely affects the time and cost efficiency of their production as well as the required material requirements. To circumvent this problem, the inventors proposethat the rollers of the cassette unit can rather be designed as non-driven rollers, provided that a corresponding drive unit is provided in the base unit, which, when the cassette unit is inserted into the cassette receptacle of the base unit, can engage in corresponding engagement recesses of the rollers by means of suitable connecting elements in order to enable the drive of the guide arrangement of the cassette unit by the drive unit of the base unit, so that the requirements for the functionality and design of the cassette unit can be advantageously considerably reduced. It can be seen as an advantage that interlocking connecting elements and engagement recesses enable additional stabilization of the cassette unit in the cassette receptacle of the base unit. An application device according to the invention is preferred,wherein the feed roller and the take-up roller in the cassette unit are designed as non-driven rollers. In this case, an application device according to the invention is preferred, wherein the base unit comprises a drive unit for driving the guide arrangement of the cassette unit. Particularly preferred in this respect is an application device according to the invention, wherein the feed roller and / or the take-up roller, preferably the feed roller and the take-up roller, comprise a central structured engagement recess, wherein the central structured engagement recess preferably has a toothed structure. Accordingly, an application device according to the invention is also particularly preferred, wherein the drive unit comprises one or more connecting elements arranged in the region of the cassette receptacle, which are designed to engage in the engagement recess of the feed roller and / or the take-up roller and create a positive connection.which enables the drive of the guide arrangement by the drive unit. In other words, an application device according to the invention is particularly preferred, wherein the cassette unit is arranged in the cassette receptacle such that the connecting elements of the drive unit engage positively in the engagement recess of the feed roller and / or the take-up roller, so that a drive of the guide arrangement by the drive unit is possible. The connecting elements are fundamentally not limited in terms of their design. However, in the opinion of the inventors, connecting elements with at least partially movable elements are particularly suitable, for example, foldable grippers or gripping devices based on movable ball elements, with which a positive connection between the connecting elements and the rollers can be achieved by moving the movable elements. This makes it possible, for example,The cassette unit can be inserted particularly easily into the base unit in the initial position of the movable elements, and only then, through the movement of the movable elements, can the necessary engagement of the connecting elements in the engagement recess be achieved. Regardless of the positioning of the drive unit used to guide the tape, the inventors believe it is particularly advantageous that the necessary guidance of the material tape in the cassette unit in application devices according to the invention can be achieved so efficiently simply by the arrangement of the rollers that only a few stationary deflection elements can be used to guide the material tape, so that no complex structures of movable guide devices, in particular no position-adjustable web tension elements, are required.to realize the necessary guidance of the material strip. An application device according to the invention is preferred, wherein the guide arrangement does not comprise any further movable guide devices, in particular no further guide rollers and / or movable web tensioning elements. At least theoretically, it is possible to design the cassette unit as an open cassette unit, in which the feed roller, the take-up roller, and the dispensing edge are placed, for example, on a simple carrier plate. However, this is not only considered disadvantageous by the inventors from an aesthetic point of view. Rather, in these embodiments, the adhesive elements are at least partially exposed, whereby the adhesive layer can also be accessible, at least in the edge region. This can be considered disadvantageous with regard to contamination of the die-cuts, but also with regard to drying out. For this purpose, the inventors believe it is advantageousInstead, a housing should be provided in which the essential parts of the cassette unit are arranged, so that they are at least partially protected from environmental influences, for example light. A corresponding design also proves advantageous in many cases with regard to the handling and storability of the refill cassettes. Since the application element of the base unit must accommodate the adhesive element, a design with a cassette unit with a housing usually means that the housing comprises a corresponding dispensing opening in the region of the dispensing area, through which the adhesive element separated from the web-shaped release material can be dispensed from the housing. An application device according to the invention is preferred, wherein the cassette unit comprises a housing in which the guide arrangement and the dispensing edge are arranged, wherein the housing comprises a dispensing opening in the dispensing area,wherein the cassette unit is configured to dispense the adhesive elements through the dispensing opening. It can be seen as an advantage of the application device according to the invention that it is suitable for applying a wide range of different adhesive elements. Due to their high practical relevance, the application of so-called die-cuts, in particular die-cuts with a diameter in the range of 10 to 80 mm, preferably in the range of 20 to 60 mm, is of particular importance. These are adhesive elements that can be obtained, for example, by punching out the adhesive element from a larger adhesive composite, wherein the adhesive composite comprises an adhesive layer and a carrier layer arranged on the adhesive layer, from which the adhesive layers or carrier layers of the adhesive elements result after the punching process. Thus, an application device according to the invention is preferred,wherein the adhesive elements are diecuts. The person skilled in the art will understand that the above definition means that the adhesive elements comprise at least one carrier layer and at least one adhesive layer, so that multi-layer structures of the adhesive elements are also conceivable. In particular, adhesive elements with multi-layer carrier layers can also be used accordingly. The adhesive elements applied in the process according to the invention with application devices according to the invention will, in the vast majority of cases, be pressure-sensitive adhesive elements, i.e., adhesive elements which, as a result of an adhesive layer made of pressure-sensitive adhesive composition, have pressure-sensitive adhesive properties. Corresponding pressure-sensitive adhesive elements are advantageously self-adhesive without an additional curing step and can be applied particularly easily to substrates, where they develop their adhesive strength.without the need for further curing steps. As an additional advantage, pressure-sensitive adhesive elements can also be removed comparatively more easily if necessary, for example in order to subsequently correct the position of an incorrectly applied pressure-sensitive adhesive element. Preference is given to an application device according to the invention, wherein the adhesive elements are pressure-sensitive adhesive elements. Preference is also given to an application device according to the invention, wherein the adhesive layer comprises a pressure-sensitive adhesive, wherein the adhesive layer preferably consists of a pressure-sensitive adhesive. A pressure-sensitive adhesive is, in accordance with the expert understanding, an adhesive that has pressure-sensitive adhesive properties, i.e., the property of forming a permanent bond to an adhesive substrate even under relatively light pressure. Corresponding pressure-sensitive adhesive elements are generally permanently tacky even at room temperature, which meansthat they exhibit a certain viscosity and tackiness, so that they wet the surface of a substrate even under low contact pressure. Without wishing to be bound by this theory, it is often assumed that a pressure-sensitive adhesive can be regarded as an extremely viscous liquid with an elastic component, which consequently exhibits characteristic viscoelastic properties that lead to the permanent inherent tack and pressure-sensitive adhesive capacity described above. It is assumed that with such pressure-sensitive adhesives, both viscous flow processes and the build-up of elastic restoring forces occur upon mechanical deformation. The partial viscous flow serves to achieve adhesion, while the partial elastic restoring forces are particularly necessary to achieve cohesion. The relationships between rheology and pressure-sensitive tack are known in the art and are described, for example, in "Satas,Handbook of Pressure Sensitive Adhesives Technology", Third Edition, (1999), pages 153 to 203. To characterize the degree of elastic and viscous components, the storage modulus (G') and the loss modulus (G'') are usually used, which can be determined by means of dynamic mechanical analysis (DMA), for example using a rheometer, as disclosed, for example, in WO 2015 / 189323. In the context of the present invention, an adhesive is preferably understood as pressure-sensitive and thus as a pressure-sensitive adhesive if, at a temperature of 23 °C in the deformation frequency range of 10, 0 up to 10 1 rad / sec G' and G'' each at least partly in the range of 10 3 up to 10 7Pa. It can be seen as an advantage of the application device according to the invention that it is very flexible with regard to the chemical composition of the adhesive used in the adhesive layer, so that essentially all adhesives familiar to the person skilled in the art can be used and the person skilled in the art essentially bases the selection of a suitable adhesive on the respective application requirements. In addition to the adhesive layer, the adhesive elements arranged on the web-shaped release material also comprise a carrier layer. In the context of the present invention, the term carrier layer is to be understood broadly and functionally, so that even thinner coatings, for example a varnish with a varnish layer, are to be understood as a carrier layer.The person skilled in the art will understand that, within the scope of the invention, the carrier layer in most cases primarily serves the purpose of reducing the stickiness of the side of the adhesive elements facing away from the adhesive side, or desirably eliminating it entirely. This serves the particular purpose of ensuring that the adhesive elements transferred to the conveyor element with the adhesive layer facing downwards can be efficiently picked up by the application element on the non-sticky carrier layer without sticking to the application element. In the inventors' opinion, in practice, it will therefore be expedient to have at least a temporary coating that reduces the stickiness in the contact area of ​​the application element, at least at the time of application.In the vast majority of cases, however, the adhesive elements will have a permanent carrier layer which is essentially permanently non-sticky, so that advantageously, after application of the adhesive elements to the substrate, the smallest possible sticky surface remains permanently. The person skilled in the art will understand in this respect that, even if it would at least theoretically be conceivable to use adhesive elements which are sticky on both sides, i.e. adhesive elements which have an adhesive layer on both sides of the carrier layer, such a process is significantly less preferred with regard to clean handling of the application process. In the vast majority of cases, an application device according to the invention is therefore preferred, wherein the side of the adhesive elements facing away from the adhesive layer is formed by the carrier layer.It can be seen as an advantage of the application device according to the invention that the carrier layer can be produced from typical materials that are used in the field of adhesive technology for corresponding carrier layers. An example in this regard is an application device according to the invention, wherein the carrier layer comprises one or more materials selected from the group consisting of polyethylene, polypropylene, cyclic olefin copolymers, polyvinyl chloride, polyester, ethylene-vinyl alcohol, polyvinylidene chloride, polyvinylidene fluoride, polyacrylonitrile, polycarbonate, polyamide, polyethersulfone and polyimide, preferably selected from the group consisting of polyethylene, polypropylene and polyethylene terephthalate, wherein the carrier layer preferably consists of these materials. So-called liners, for example, can be used as the web-shaped release material on which the adhesive elements are arranged in the material strip.Functionally, however, any web-like material with a reduced-adhesion surface can be used. With regard to the reduced-adhesion surface, the following statements regarding the reduced-adhesion surface of the conveying element apply accordingly. The degree of necessary adhesion reduction can be tailored to the chemical nature of the adhesive and the structural design of the dispensing edge in order to ensure efficient separation of the adhesive elements from the release material. Particular preference is given to web-like release materials that have a so-called siliconization and consequently have a reduced-adhesion surface. An application device according to the invention is preferred, wherein the web-like release material is a material with a reduced-adhesion surface, for example, a liner.Particularly preferred is an application device according to the invention, wherein the web-shaped release material is coated with a release layer on the side facing the adhesive elements, preferably with a silicone release layer, wherein the silicone release layer can preferably be produced by crosslinking a crosslinkable silicone system comprising one or more polysiloxanes. The advantageous design of application devices according to the invention with an exchangeable refill cassette advantageously allows the use of comparatively short material strips without excessive restrictions in the efficiency of the process, since emptied material strips can be replaced quickly and efficiently, so that the loss of efficiency compared to very long material strips is only minimal.In return, however, the short material strips achieve handling advantages, in particular in the weight of the cassette unit and accordingly also in the weight of the application device according to the invention, which is particularly advantageous when used as an end effector. Against this background, an application device according to the invention is preferred, wherein the web-shaped release material has a length in the range of 30 to 300 m, preferably in the range of 40 to 250 m, particularly preferably in the range of 50 to 200 m. Additionally or alternatively, an application device according to the invention is preferred, wherein the feed roller has a diameter of 500 mm or less, preferably 450 mm or less, particularly preferably 420 mm or less.In application devices according to the invention, an adhesive element dispensed from the cassette unit is transferred with the adhesive layer facing downwards onto the conveyor element, from which the adhesive element can then be picked up with the application element. The conveyor element thus serves the purpose of guiding the adhesive element from the dispensing area of ​​the cassette unit to a receiving area in which the application element can pick it up. According to the inventors' assessment, a very wide variety of conveyor element designs are theoretically conceivable, for example, even designs that can be operated exclusively discontinuously, which, for example, rely on a movable slider onto which the adhesive element is transferred near the dispensing edge and which is then moved in the direction of the application element.However, in the opinion of the inventors, a solution is preferred for essentially all embodiments in which a continuously operable conveyor element is used, which can in particular be designed as a circulating conveyor belt. A corresponding conveyor belt allows reliable and precisely controllable conveying of the adhesive elements and can in particular also be arranged in a fixed position in the base unit, so that sources of error during the transfer of the adhesive elements from the cassette unit can be reduced. For essentially all embodiments, an application device according to the invention is preferred, wherein the conveyor element comprises a circulating conveyor belt. Additionally or alternatively, an application device according to the invention is preferred, wherein the conveyor element is arranged in a fixed position in the base unit.For the purpose of the most precise and controlled pick-up of the adhesive elements by the application element, the inventors believe it is advantageous for many types of application elements to set up discontinuous operation, despite the continuous operability of the circulating conveyor belt during use, so that the conveyed adhesive element is at rest at the moment of pick-up by the application element. However, there are also embodiments in which largely continuous conveying can be expedient, for example, when the adhesive elements are to be transferred from the conveyor element to a continuously operating application element, for example in the form of an application roller. The person skilled in the art understands that a conventional circulating conveyor belt, such as could be used for an arrangement according to EP 3569534 A1, is not necessarily suitable for use in application devices according to the invention.This is because, contrary to the teachings of the prior art, the adhesive elements are transferred to the conveyor element with the adhesive layer facing downwards. Without further measures, the adhesive elements would therefore in many cases adhere wholly or partially to the conveyor element and in many cases could no longer be picked up efficiently by the application element, at least not without the risk of adhesive residue remaining on the conveyor element and the adhesive layer of the adhesive elements to be applied being damaged accordingly. In addition, in this case the demands on the application element, or the bond strength achievable with it when picking up the adhesive elements, would increase considerably. For this reason, in application devices according to the invention, a conveyor element is used whose surface is designed such that the adhesive elements, or their adhesive layers, show reduced adhesion to the surface.A corresponding design is readily implemented by a person skilled in the art with knowledge of the invention, as they are familiar with the concept of adhesion-reduced surfaces from many other areas of adhesive technology, where it is regularly used, for example, in connection with typical liners. In practice, it is difficult to specify absolute values ​​for the acting forces and the necessary degree of adhesion reduction. The tolerable adhesion forces between the adhesive elements and the adhesion-reduced surface of the conveying element depend essentially on the physicochemical properties of the adhesive used, in particular its cohesion, as well as the bond strength that the application element can generate in the short term with the carrier layer of the adhesive elements.In practice, the selection of the adhesive used in the adhesive layer will in most cases depend on the application requirements regarding the bond strength to the substrate to be bonded. Having identified an adhesive suitable for interaction with the substrate, the skilled person can then make a suitable selection for the material of the conveying element or its coating, for which the respective adhesive exhibits sufficiently low adhesion, allowing the adhesive element to be absorbed by the application element.In this respect, the inventors propose that the extent of adhesion of the adhesive element to the adhesion-reduced surface should expediently be specified in relation to the adhesion of the adhesive element to the substrate to be bonded and / or in relation to the bond strength that the respective application element can form with the adhesive element at the moment the adhesive element is picked up, since these interactions should both be expediently greater than the adhesion of the adhesive element to the conveying element. Accordingly, an application device according to the invention is preferred, wherein the adhesion-reduced surface is designed such that the adhesion of the adhesive element to the adhesion-reduced surface is smaller, preferably by 80% or more, particularly preferably by 90% or more, most particularly preferably by 95% or more, than the adhesion of the adhesive element to the substrate to be bonded.Additionally or alternatively, an application device according to the invention is preferred, wherein the adhesion-reduced surface is designed such that the adhesion of the adhesive element to the adhesion-reduced surface is smaller, preferably by 80% or more, particularly preferably by 90% or more, most particularly preferably by 95% or more, than the connection strength between the application element and the adhesive element when the adhesive element is picked up by the application element. In particular, if the position of the adhesive elements on the conveying element is to be further influenced by the use of guide elements and / or stopper elements, as disclosed below, it is preferable to provide a particularly pronounced adhesion reduction in order to allow easy displacement of the adhesive elements on the adhesion-reduced surface.In the inventors' opinion, a coating of the surface of the conveying element with a silicon coating, as is also used, for example, in many liners, is particularly suitable for obtaining an adhesion-reduced surface. An application device according to the invention is particularly preferred, wherein the adhesion-reduced surface is coated with a release layer, preferably with a silicone release layer, wherein the silicone release layer can preferably be produced by crosslinking a crosslinkable silicone system comprising one or more polysiloxanes. It can be seen as an advantage of the method according to the invention that the adhesive elements are applied to the conveying element with the adhesive layer facing downwards, and consequently, despite the adhesion-reduced surface, at least some residual adhesion remains, resulting from the tackiness of the adhesive layer.Especially in the case of stationary application devices according to the invention, which are not intended to be moved through space, for example as part of a robot arm, it is advantageous in many cases to dispense with the need for an additional fixing mechanism for the adhesive elements on the conveying element, such as a suction function, particularly in conjunction with the fact that the application element ultimately carries out the final application step. By omitting such a suction function on the conveying element, the equipment required can be significantly reduced, since, for example, no pumps or the corresponding fluid lines need to be provided.Particularly preferred for more stationary applications is an application device according to the invention, wherein the conveying element is not configured to additionally fix the adhesive elements arranged on the surface of the conveying element by means of a negative pressure acting through perforations in the surface of the conveying element. In these cases, an application device according to the invention is also preferred, wherein the conveying element does not comprise a suction function for fixing the adhesive elements to the surface of the conveying element. Consequently, an application device according to the invention is also preferred, wherein the conveying element does not comprise a device for generating a negative pressure.Despite the possibility described above of being able to design the application device according to the invention with a particularly simple construction, the inventors believe that for most applications it is nevertheless preferable to provide the application device according to the invention with a corresponding suction function on the conveyor element, as can be achieved, for example, with a suction belt. The reason for this is that, particularly when used on the end effector of a robot arm that is potentially subject to rapid movement, forces can act which could cause the adhesive elements to become detached, even though they are adhered to the conveyor element with the adhesive layer, since this adhesion is deliberately reduced as a result of the adhesion-reduced surface. Nevertheless, synergistic advantages also arise in this case, since the additional adhesive effect can reduce the strength of the suction function and / or also compensate for fluctuations in performance orIn the event of a brief failure of the suction function, it is still possible to fix the adhesive elements on the surface of the conveying element and to prevent them from falling off, at least in the absence of strong acceleration forces. An application device according to the invention is particularly preferred, wherein the conveying element is designed to additionally fix the adhesive elements arranged on the surface of the conveying element by means of a negative pressure acting through perforations in the surface of the conveying element. Accordingly, an application device according to the invention is also particularly preferred, wherein the conveying element comprises a suction function for fixing the adhesive elements on the surface of the conveying element. An application device according to the invention is therefore also particularly preferred, wherein the conveying element comprises a device for generating a negative pressure.As disclosed above, discontinuous operation of the conveyor unit is preferred in most cases. Those skilled in the art will understand that, even in this discontinuous operation, the conveying speed of the conveyor element should be coordinated to a certain extent with the guide speed of the material strip in the guide arrangement. In this respect, the inventors propose that two different process configurations are particularly expedient for this purpose. In the first embodiment, the conveying speed can essentially correspond to the guide speed in the guide arrangement, which generally ensures particularly good transfer from the dispensing edge to the conveyor element and, when using a continuously operating conveyor element, also enables the most continuous replenishment possible.In this case, an application device according to the invention is preferred, wherein the conveying element is designed to convey an adhesive element dispensed from the cassette unit in the application device away from the cassette unit, wherein the conveying speed v. F relative to the cassette unit preferably by 10% or less, particularly preferably by 5% or less, most particularly preferably by 1% or less, of the guide speed of the material strip v M in the guide arrangement, whereby the conveying speed v F particularly preferably not less than the guide speed v Mof the material strip in the guide arrangement. However, the inventors have found that a speed difference between the material strip and the conveyor element can advantageously lead to the separation of the adhesive elements on the conveyor element if these are arranged on the material strip for the purpose of optimised space utilization. For example, round die-cuts can be arranged on the material strip in accordance with a dense packing, so that the largest possible number of adhesive elements per area of ​​the material strip can be achieved. Separation of the adhesive elements is usually desired in these cases in order to achieve increased precision in the pick-up of the adhesive elements. Different speeds are also advantageous if the conveyor element has to bridge a relatively large distance to the application element and it is desired for the process control that, for example, only oneAdhesive element rests on the conveyor unit. For many cases, therefore, an application device according to the invention is preferred, wherein the conveying speed of the conveyor element vF is higher than the guide speed of the material strip vM in the guide arrangement, wherein the conveying speed of the conveyor element is preferably at least 2*vM or more, particularly preferably at least 3*vM or more, very particularly preferably at least 4*vM or more, especially preferably at least 5*vM or more. It can be seen as an advantage of the application device according to the invention that it is very flexible with regard to the application element used for the final application, so that, for example, rollers or the like can also be used, wherein with a view to practical implementation, in the vast majority of cases a requirement will be that the application element should be designed to form a reversiblyand non-destructively detachable connection. To implement this functionality of the application element, which is designed to form a reversibly and non-destructively detachable connection with an adhesive element, the person skilled in the art can resort to various solutions known from the prior art. The person skilled in the art understands that the above-described device of the application element being able to form a reversibly and non-destructively detachable connection with an adhesive element does not require that the connection be released by the removal of the connecting force, as could be achieved, for example, by switching off a magnetic field in the case of a magnetic connection or by switching off a suction function. Rather, it is also possible, and in practice often particularly efficient, if the reversible and non-destructive release occurs against the acting forces that determine the connection.In particular, it can be exploited that the adhesion of the adhesive elements to the substrate is in many cases significantly greater than the force requiring the connection to the application element, so that the connection can be made, for example, against a suction-acting negative pressure when the application element is moved away from the substrate. The reversibly and non-destructively detachable connection can, at least in theory, be achieved, for example, by a magnet arrangement that interacts, for example, with a magnetic carrier layer of the adhesive elements, or theoretically also by suction cups or a pressure-sensitive adhesive. However, due to the high reliability, simple design implementation and longevity of such a solution, the use of a vacuum-based suction solution is particularly preferred. In the inventors' opinion, an application element is particularly preferred, which comprises a piston arrangement with a movablePiston arranged suction gripper, since with these application elements a particularly precise and efficient application of the adhesive elements is possible. In this case, the application element is aligned with the conveying element and the controllable suction gripper with the movable piston is lowered onto the conveying element in order to contact the adhesive element located thereon on the carrier layer with the suction gripper and to establish a reversible and non-destructive connection. By moving the piston again, the adhesive element can be lifted from the conveying element and aligned in the direction of the substrate by means of the movement unit, before an application movement takes place which contacts the adhesive layer with the substrate, so that the connection between the adhesive element and the application element can be dissolved. Accordingly, an application device according to the invention is preferred, wherein the application element has a movement unit and aMovement unit arranged receiving unit, wherein the receiving unit is designed to form a reversibly and non-destructively detachable connection with the carrier layer of the adhesive elements. In this respect, an application device according to the invention is particularly preferred, wherein the receiving unit comprises one or more controllable suction grippers, wherein the application device preferably comprises one or more vacuum pumps connected to the suction grippers. Additionally or alternatively, an application device according to the invention is preferred, wherein the movement unit comprises a piston arrangement with a cylinder and a piston movable in the cylinder, wherein the movement unit preferably comprises a rotation device for rotating the piston arrangement, wherein the rotation axis preferably runs substantially parallel to the surface of the conveying element. In particularly preferred embodiments, the application element can be designed as a rotatableThe application element can be designed as an application element, which comprises a corresponding movable piston and suction gripper on both sides. Thus, after receiving a first adhesive element, the application element can be rotated about a rotation axis in order to align the received adhesive element towards a substrate, onto which it can be pressed by moving the piston. In the meantime, on the back of the application element, another movable piston with a corresponding suction gripper is ready to receive a further adhesive element for the next application. In a preferred alternative embodiment, the different dimensioning of the suction grippers at the different ends of the movement unit allows the application of adhesive elements of different geometric shapes and / or different dimensions. If, for example, two differentIf cassette units with adhesive elements of different diameters are to be used, in this embodiment, the differently dimensioned adhesive elements can be applied by selecting the receiving surface of the two suction grippers corresponding to the two different diameters of the adhesive elements. This results in an application device according to the invention, with which a precise application of differently dimensioned adhesive elements is made possible particularly efficiently, without requiring a change of the application element. Particularly preferred is an application device according to the invention, wherein the application element comprises two or more receiving units, wherein the receiving units preferably have different dimensions. Based on this concept, application devices according to the invention are also preferred, wherein the application element has 3 or more, preferably 4 or more, particularly preferably 5 ormore, comprises receiving units, wherein the receiving units preferably have different dimensions. As explained above, in order to ensure a reliable transfer of the adhesive elements via the dispensing edge to the conveying element, it is expedient not to select too large a distance between these elements. In this respect, the inventors have succeeded in specifying particularly suitable distances for this purpose. An application device according to the invention is preferred, wherein the cassette unit is arranged in the base unit such that the distance between the end of the dispensing edge pointing towards the conveying element and the conveying element is 0.3*LK or less, preferably 0.2*LK or less, particularly preferably 0.1*LK or less, most particularly preferably 0.05*LK or less, wherein LK is the average length of the adhesive elements in the web direction of the material web. Additionally or alternatively, an application device according to the invention is preferred, wherein theThe cassette unit is arranged in the base unit such that the distance between the end of the dispensing edge pointing towards the conveying element and the conveying element is 10 mm or less, preferably 8 mm or less, particularly preferably 6 mm or less, most particularly preferably 4 mm or less. In order to ensure the most reliable transfer of the dispensed adhesive element to the conveying element, the inventors propose that a pressure roller can also be provided in the transfer area, by means of which the adhesive element can be additionally guided and pressed against the conveying element during transfer to the conveying element. In the inventors' opinion, such a configuration is particularly advantageous when the conveying element does not have a suction function and the adhesive elements are solely fixed by their adhesion. Thus, an application device according to the invention is preferred, wherein the application device comprises one or morePressure rollers, preferably as part of the base unit, wherein the one or more pressure rollers are arranged opposite the surface of the conveyor element and are configured to press the adhesive element dispensed from the cassette unit onto the surface of the conveyor element to improve adhesion. Particularly for applications requiring high precision, it may be expedient to verify the correct positioning of the adhesive elements on the conveyor element before they are picked up by the application element. The inventors propose that the application device according to the invention can be equipped with sensor units for this purpose, for example optical sensors that can detect correct placement of the adhesive elements on the surface of the conveyor element. Therefore, an application device according to the invention is preferred, wherein the application device comprises one or more sensor unitscomprises, preferably as part of the base unit, wherein the one or more sensor units are configured to detect the position of adhesive elements on the surface of the conveying element, wherein the control of the application element preferably takes place as a function of data recorded with the one or more sensor units. In addition or as an alternative to the provision of detection units, the inventors propose that, in order to ensure a secure and precisely positioned supply of the adhesive elements on the conveying element to the application element, guide elements can also be provided, in particular baffles, for example in the shape of a V open at the bottom, or in the form of two guide elements offset from one another. Advantageously, the adhesion-reduced surface of the conveying element ensures that a displacement of the adhesive elements on the surface of the conveying element is possible without any problems in many cases.so that in particular the position of the adhesive elements can be adjusted transversely to their direction of movement, i.e. the conveying direction of the conveying element. If the conveying element is designed with a vacuum-based fixation, a displacement of the adhesive elements on the surface of the conveying element by guide elements can be supported by areas in which the contact pressure exerted by the suction function is reduced. An application device according to the invention is preferred, wherein the application device comprises one or more guide elements, preferably as part of the base unit, wherein the one or more guide elements are configured to adjust the position of adhesive elements arranged on the conveying element. Furthermore, the inventors propose, in addition to or alternatively to the repositioning of the adhesive elements by guide elements, a stopper element for fixing the position of the adhesive elements on apredetermined position of the conveying element on the application device, which functions as a kind of stopper and fixes the adhesive elements before they are picked up by the application element. The stopper element can additionally be designed to reposition the adhesive elements transversely to the conveying direction, so that advantageously no separate guide elements are required. Due to the adhesion-reduced surface of the conveying element, both repositioning of the adhesive elements and fixing can be carried out in a simple manner, in that the stopper element blocks movement of the adhesive element in the direction of movement of the conveying element at a predefined position. If the person skilled in the art designs the application device according to the invention such that the adhesive elements can be moved relatively easily on the adhesion-reduced surface, it is advantageously even possible to adjust the position of the adhesive elementas the conveyor belt continues to run and / or follows, so that the adhesive element is moved on the adhesion-reduced surface against the conveying direction. The inventors propose that the conveying direction of the conveyor element can be inverted, for example after the position of an adhesive element has been fixed by a stopper element, even briefly, in order to detach the adhesive element from the stopper element and achieve increased precision in the reception of the adhesive element by the application element or to prevent contamination of the stopper element with adhesive. Therefore, an application device according to the invention is preferred, wherein the application device comprises a stopper element, preferably as part of the base unit, wherein the stopper element is designed to fix the position of adhesive elements arranged on the conveyor element in the conveying direction of the conveyor element, so that the adhesive elements are moved when the conveyor element movesrelative to the adhesion-reduced surface. In light of the above explanations, the person skilled in the art will understand that the present invention also relates to the cassette unit particularly suitable for use in the application devices according to the invention and to a complementary base unit for receiving this preferred cassette unit. The invention accordingly also relates to a cassette unit for an application device according to the invention, comprising: a1) a guide arrangement comprising a feed roller and a take-up roller, a2) an output area with a dispensing edge, a3) a material strip comprising a plurality of adhesive elements with a carrier layer and an adhesive layer connected thereto, wherein the adhesive elements with the adhesive layer are arranged on a web-shaped release material, wherein the cassette unit is designed such that the material strip provided on the feed roller is guided over the dispensing edge to the take-up rollercan be guided such that the adhesive elements are separated from the release material in the output area and are output from the cassette unit, wherein the feed roller and the take-up roller in the cassette unit are designed as non-driven rollers, wherein the feed roller and / or the take-up roller comprise a central structured engagement recess, wherein the cassette unit is designed such that, when the cassette unit is arranged in the cassette receptacle of a base unit, a positive connection can be created via the engagement of one or more connecting elements of a drive unit of the base unit in the engagement recess of the feed roller and / or the take-up roller, which enables the drive of the guide arrangement by the drive unit. The invention accordingly also relates to a base unit for an application device according to the invention, comprising: b1) a cassette receptacle for receiving a cassette unit, b2) a conveying element withan adhesion-reduced surface, and b3) an application element, wherein the base unit is configured to receive an adhesive element arranged on the conveyor element with the application element and to apply it to a substrate to be bonded. The invention further relates to a method for applying adhesive elements to substrates to be bonded with an application device according to the invention, comprising the method steps: i) producing or providing a substrate to be bonded, ii) guiding the material strip provided on the feed roll in the guide arrangement over the dispensing edge to separate an adhesive element from the web-shaped release material and dispensing the adhesive element from the cassette unit, iii) transferring the dispensed adhesive element with the adhesive layer onto the adhesion-reduced surface of the conveyor element, iv) receiving the transferred adhesive element with the application element to form a reversibly andnon-destructively detachable connection between the application element and the carrier layer of the transferred adhesive element, and v) applying the received adhesive element to the substrate to be bonded and dissolving the connection between the application element and the carrier layer of the applied adhesive element. A method according to the invention is preferred, wherein the position of adhesive elements arranged on the conveyor element is adjusted by one or more guide elements before the pickup in method step iv). A method according to the invention is preferred, wherein the substrate to be bonded is a vehicle component. A method according to the invention is also preferred, wherein the substrate to be bonded comprises a recess, wherein the adhesive element is applied in order to at least partially, preferably substantially completely, close the recess, preferably to close it in a fluid-tight manner. Finally, a method for feedingan application device according to the invention, comprising the method steps: x) removing the first cassette unit arranged reversibly and non-destructively in the cassette holder of the base unit, y) inserting a second cassette unit into the cassette holder of the base unit, and z) reconditioning the first cassette unit by replacing the feed roller and the take-up roller in the first cassette unit with a replacement feed roller and a replacement take-up roller to obtain a reconditioned cassette unit. Preferred embodiments of the invention are explained and described in more detail below with reference to the attached figure. Therein: Fig. 1 shows a schematic representation of an application device according to the invention in a preferred embodiment in a side view with a transparent housing of the cassette unit; Fig. 2 shows a schematic representation of the application device according to the invention of Fig. 1 ina perspective view with the housing of the cassette unit closed; and Fig. 3 is a schematic representation of a section of a material strip and a conveyor element of an application device according to the invention in a preferred embodiment in plan view. Fig. 1 shows a schematic representation of an application device 10 according to the invention for applying adhesive elements 12a, 12b to substrates to be bonded, in a side view with a transparent housing of the cassette unit 14, so that the interior of the cassette unit 14 is clearly visible. In the example shown in Fig. 1, the application device 10 is designed as an end effector, which can be attached, for example, to a robot arm. The application device 10 comprises a cassette unit 14, in the housing of which a stationary dispensing edge 20 and a guide arrangement with a feed roller 16 and a take-up roller 18 are arranged. The dispensing edge, designed as a knife edge20 is arranged in the output area of ​​the cassette unit 14 at an output opening of the housing, thereby designating the location of the cassette unit 14 at which the adhesive elements 12a-b are transferred to the base unit 24. The cassette unit 14 also comprises a material strip 22 with a plurality of adhesive elements 12a-b, which are arranged with their adhesive layer on a web-shaped release material such that the carrier layer of the adhesive elements 12a-b faces away from the web-shaped release material. The material strip 22 is tensioned in the guide arrangement between the feed roll 16, on which it is initially provided, and the take-up roll 18, on which the web-shaped release material is successively wound. The cassette unit 14 is arranged in the cassette receptacle of the base unit 24 of the application device 10, which is provided for receiving the cassette unit 14 and into which the cassette unit 14 can be reversibly and non-destructively replaced.can be used, which in the example shown in Fig. 1 is supported by a magnetic connection mechanism. This allows a used cassette unit 14 to be removed for refilling the application device 10 with material band 22 and replaced by a filled cassette unit 14. The base unit 24 comprises a drive unit for driving the guide arrangement, with two connecting elements 32a, 32b, as well as an electronic data processing device (not shown) for controlling the application device 10, in particular the drive unit. The drive unit serves to drive the guide arrangement of the cassette unit 14, which in the example shown are each designed without their own drive. For the necessary power transmission, the feed roller 16 and the take-up roller 18 each have a central structured engagement recess 30a, 30b with a toothed structure, so that they can engage with the complementaryConnecting elements 32a-b of the drive unit can create a positive connection through which the guide arrangement can be driven. The base unit 24 further comprises an application element 28 and a positionally fixed conveyor element 26 with a reduced-adhesion surface coated with a silicone release layer. The conveyor element 26 is designed as a circulating conveyor belt and, in the example shown, is arranged in the base unit 24 such that the distance between the end of the dispensing edge 20 pointing towards the conveyor element 26 and the conveyor element 26 is approximately 3 mm. Based on the basic arrangement shown, the base unit 24 can also have sensor units for detecting the position of the adhesive elements 12a-b on the surface of the conveyor element 26 as well as guide elements for adjusting the position of adhesive elements 12a-b arranged on the conveyor element 26 (not shown). The application element 28 comprises, in the example showna rotatable movement unit, which has a piston arrangement with a cylinder on both sides and a piston movable within the cylinder. The application element 28 also comprises a controllable suction gripper arranged on each side of the movement unit. Fig. 2 shows the application device 10 shown in Fig. 1 in a perspective view with a closed housing of the cassette unit 14. The application device 10 shown is particularly suitable for use in a method according to the invention for applying adhesive elements 12a-b to substrates to be bonded, for example vehicle components, in order to bond holes and other recesses in these in a fluid-tight manner. For this purpose, the cassette unit 14 is first loaded with the material strip 22 so that it can be unrolled from the feed roll 16 in the guide arrangement. The cassette unit 14 can then be inserted into the cassette receptacle of the base unit 24.be used so that the connecting elements 32a-b of the drive unit of the base unit 24 can engage in the corresponding toothed engagement recesses 30a, 30b of the feed roller 16 and the take-up roller 18, wherein the connecting elements 32a-b in the example shown are provided with movable elements by which the positive connection is established. The automated movement unit moves the application device 10, which functions as an end effector, to its destination near the recess in the substrate to be covered. By activating the drive unit via the electronic data processing device, the feed roller 16 and the take-up roller 18 are set in rotation, so that the material strip 22 with the adhesive elements 12a-b is unrolled from the feed roller 16 and guided over the dispensing edge 20 to the take-up roller 18. The web-shaped release material, which is coated with a silicone release layer on the side facing the adhesive elements 12a-b,is deflected at the end of the dispensing edge 20 and guided further to the take-up roll 18 to be rolled up there. The deflection angle is at least 90°, but in the arrangement shown depends on the diameter of the take-up roll 18 and increases for larger take-up roll diameters. During the deflection, the adhesive elements 12a-b, which are designed, for example, as die-cuts, are separated from the web-shaped release material of the material strip 22 at the end of the dispensing edge 20 and transferred to the adhesion-reduced surface of the conveying element 26 by the conveying movement of the material strip 22, so that the pressure-sensitive adhesive layer of the adhesive elements 12a-b rests on the adhesion-reduced surface of the conveying element 26 and the carrier layer of the adhesive elements 12a-b points upwards in the direction of contact with the application element 28. An adhesive element 12a-b thus dispensed from the cassette unit 14 is conveyed by the conveyor element 26 from the cassette unit 14away towards the application element 28, wherein the conveying speed vF of the conveying element 26 relative to the cassette unit 14 is, for example, at least twice as high as the guide speed vM of the material strip 22 in the guide arrangement. Fig. 3 visualizes how, in a corresponding process control with a leading conveying element 26, during the transfer of adhesive elements 12a from the material strip 22 to the conveying element 26, a separation of the adhesive elements 12a-b can be achieved, so that the adhesive elements 12b conveyed on the adhesion-reduced surface have a greater distance from one another in the conveying direction than the adhesive elements 12a guided on the material strip 22, which were previously arranged in the manner of a densest packing. The adhesion of the adhesive elements 12a-b to the adhesion-reduced surface is, in the examples shown in Figs. 1 to 3, significantly smaller than the adhesion of the adhesive element 12a-b on thesubstrate to be bonded or as the bond strength between the application element 28 and the adhesive element 12a-b after the adhesive element 12a-b has been received. In the example shown in Fig. 3, the absolute value of the adhesion is chosen to be so low that a displacement of the adhesive elements 12a-b relative to the adhesion-reduced surface is possible without damaging the adhesive layer. In the example shown in Figs. 1 to 3, the adhesive elements 12a-b arranged on the surface of the conveyor element 26 are additionally fixed by a negative pressure acting through a plurality of perforations 36 in the surface of the conveyor element 26 designed as a suction belt. For increased precision in the positioning of the adhesive elements 12a-b on the conveyor element 26, the sensor units of the base unit 24 can detect the position of the adhesive elements 12a-b on the surface of the conveyor element 26. Depending on the position data thus determined, subsequent, for example byGuide elements of the base unit 24, the desired positions of the adhesive elements 12a-b on the conveyor element 26 can be adjusted or corrected, so that the adhesive element 12a-b guided on the conveyor element 26 can be picked up particularly precisely by one of the two suction grippers of the application element 28 shown in Fig. 1. In addition, as shown in Fig. 3, a stopper element 34 can increase the precision of the positioning of the adhesive element 12b guided on the conveyor element 26, in particular when picking up the adhesive element 12b by the application element 28, by blocking the conveyance of the adhesive element 12b in the conveying direction on the conveyor element 26 at a predefined position. For picking up the adhesive element 12a-b, a vacuum is generated between one of the suction grippers of the application element 28 and the adhesive element 12a-b to be applied via a vacuum pump, so that a reversibly and non-destructively detachable connection between theCarrier layer of the adhesive element 12a-b and the suction gripper is created. By rotating the suction grippers, for example, about a rotation axis running essentially parallel to the surface of the conveying element 26, the adhesive element 12a-b with the adhesive layer can be applied to a substrate to be bonded, for example, running above the conveying element 26, by the suction gripper pressing the adhesive element 12a-b onto the substrate. In principle, in the example shown in Fig. 1, application is possible at any position along the circular radius of the suction grippers, wherein the application takes place in particular at orientation angles in the range of 90° to 270°, starting from an angle of 0° when the adhesive element 12a-b is picked up by the application element 28. In most cases, the reversibly and non-destructively detachable connection between the suction gripper and the adhesive element 12a-b is achieved, for example, by a movement of the application device 10.be dissolved because the adhesion of the adhesive element 12a-b to the substrate is greater than the force acting as a result of the negative pressure. List of reference symbols 10 Application device 12a-b Adhesive element 14 Cassette unit 16 Feed roller 18 Take-up roller 20 Dispensing edge 22 Material belt 24 Base unit 26 Conveyor element 28 Application element 30a-b Engagement recess 32a-b Connecting elements 34 Stopper element 36 Perforation vM Guide speed of the material belt vF Conveyor speed of the conveyor element

Claims

Claims 1. Application device (10) for applying adhesive elements (12a, 12b) to substrates to be bonded, comprising: a) a cassette unit (14), comprising: a1) a guide arrangement comprising a feed roller (16) and a take-up roller (18), a2) an output region with a dispensing edge (20), and a3) a material strip (22) comprising a plurality of adhesive elements (12a, 12b) with a carrier layer and an adhesive layer connected thereto, wherein the adhesive elements (12a, 12b) are arranged with the adhesive layer on a web-shaped release material, wherein the cassette unit (14) is designed such that the material strip (22) provided on the feed roller (16) can be guided over the dispensing edge (20) to the take-up roller (18) in such a way that the adhesive elements (12a, 12b) are separated from the release material in the output region and dispensed from the cassette unit (14) b) a base unit (24),comprising: b1) a cassette holder for receiving the cassette unit (14), b2) a conveyor element (26) with an adhesion-reduced surface, and b3) an application element (28), wherein the base unit (24) is designed to receive an adhesive element (12a, 12b) arranged on the conveyor element (26) with the application element (28) and to apply it to a substrate to be bonded, and wherein the cassette unit (14) is arranged in the cassette holder so as to be reversibly and non-destructively replaceable, wherein the application device (10) is designed such that an adhesive element (12a, 12b) dispensed from the cassette unit (14) is transferred with the adhesive layer onto the adhesion-reduced surface of the conveyor element (26), so that the transferred, The adhesive element (12a, 12b) with the application element (28) can be picked up from the adhesion-reduced surface of the conveyor element (26) and applied to a substrate to be bonded.

2. The application device (10) according to claim 1, wherein the conveyor element (26) is configured to additionally fix the adhesive elements (12a, 12b) arranged on the surface of the conveyor element (26) by means of a negative pressure acting through perforations (36) in the surface of the conveyor element (26).

3. The application device (10) according to one of claims 1 or 2, wherein the conveyor element (26) comprises a circulating conveyor belt.

4. The application device (10) according to one of claims 1 to 3, wherein the adhesion-reduced surface is coated with a release layer, preferably with a silicone release layer. 5.The application device (10) according to any one of claims 1 to 4, wherein the adhesion-reduced surface is designed such that the adhesion of the adhesive element (12a, 12b) to the adhesion-reduced surface is 80% or more smaller than the bond strength between the application element (28) and the adhesive element (12a, 12b) when the adhesive element (12a, 12b) is picked up by the application element (28).

6. The application device (10) according to any one of claims 1 to 5, wherein the application device (10) comprises one or more pressure rollers, wherein the one or more pressure rollers are arranged opposite the surface of the conveyor element (26) and are configured to press the adhesive element (12a, 12b) dispensed from the cassette unit (14) onto the surface of the conveyor element (26) to improve adhesion.

7. The application device (10) according to any one of claims 1 to 6, wherein the application device comprises one or more sensor units, wherein the one or more sensor units are configured to detect the position of adhesive elements (12a, 12b) on the surface of the conveying element (26).Application device (10) according to one of claims 1 to 7, wherein the application device (10) comprises one or more guide elements, wherein the one or more guide elements are configured to adjust the position of adhesive elements (12a, 12b) arranged on the conveyor element (26) and / or wherein the application device (10) comprises a stopper element (34), wherein the stopper element (34) is configured to fix the position of adhesive elements (12a, 12b) arranged on the conveyor element (26) in the conveying direction of the conveyor element (26), so that the adhesive elements (12a, 12b) are moved relative to the adhesion-reduced surface when the conveyor element (26) moves.

9. Application device (10) according to one of claims 1 to 8, wherein the feed roller (16) and / or the take-up roller (18), preferably the feed roller (16) and the take-up roller (18), comprise a central structured engagement recess (30a, 30b).Application device (10) according to claim 9, wherein the base unit (24) comprises a drive unit for driving the guide arrangement of the cassette unit (14), wherein the drive unit comprises one or more connecting elements (32a, 32b) arranged in the region of the cassette receptacle, which are designed to engage in the engagement recess (30a, 30b) of the feed roller (16) and / or the take-up roller (18) and to create a positive connection.

11. The application device (10) according to claim 10, wherein the cassette unit (14) is arranged in the cassette receptacle such that the connecting elements (32a, 32b) of the drive unit engage positively in the engagement recess (30a, 30b) of the feed roller (16) and / or the take-up roller (18), allowing the guide arrangement to be driven by the drive unit.

12. The application device (10) according to one of claims 1 to 11, wherein the dispensing edge (20) is arranged in a fixed position in the cassette unit (14).

13. Cassette unit (14) for an application device (10) according to one of claims 1 to 12, comprising: a1) a guide arrangement comprising a feed roller (16) and a take-up roller (18), a2) an output area with a dispensing edge (20), and a3) a material band (22) comprising a plurality of adhesive elements (12a, 12b) with a carrier layer and an adhesive layer connected thereto, wherein the adhesive elements (12a,12b) are arranged with the adhesive layer on a web-shaped release material, wherein the cassette unit (14) is designed such that the material strip (22) provided on the feed roller (16) can be guided over the dispensing edge (20) to the take-up roller (18) in such a way that the adhesive elements (12a, 12b) are separated from the release material in the dispensing area and are dispensed from the cassette unit (14), wherein the feed roller (16) and the take-up roller (18) in the cassette unit (14) are designed as non-driven rollers, wherein the feed roller (16) and / or the take-up roller (18) comprise a central structured engagement recess, wherein the cassette unit (14) is designed such that when the cassette unit (14) is arranged in the cassette receptacle of a base unit (24), By engaging one or more connecting elements of a drive unit of the base unit (24) in the engagement recess of the feed roller (16) and / or the take-up roller (18), a positive connection can be created which enables the drive of the guide arrangement by the drive unit.

14. Base unit (24) for an application device (10) according to one of claims 1 to 12, comprising: b1) a cassette holder for receiving a cassette unit (14), b2) a conveyor element (26) with an adhesion-reduced surface, and b3) an application element (28), wherein the base unit (24) is configured to receive an adhesive element (12a, 12b) arranged on the conveyor element (26) with the application element (28) and to apply it to a substrate to be bonded.Method for applying adhesive elements (12a, 12b) to substrates to be bonded using an application device (10) according to one of claims 1 to 12, comprising the method steps: i) producing or providing a substrate to be bonded, ii) guiding the material strip (22) provided on the feed roll (16) in the guide arrangement over the dispensing edge (20) to separate an adhesive element (12a, 12b) from the web-shaped release material and dispensing the adhesive element (12a, 12b) from the cassette unit (14), iii) transferring the dispensed adhesive element (12a, 12b) with the adhesive layer onto the adhesion-reduced surface of the conveyor element (26). iv) picking up the transferred adhesive element (12a, 12b) with the application element (28) to form a reversibly and non-destructively detachable connection between the application element (28) and the carrier layer of the transferred adhesive element (12a, 12b), and v) applying the picked up adhesive element (12a, 12b) to the substrate to be bonded and dissolving the connection between the application element (28) and the carrier layer of the applied adhesive element (12a, 12b).

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