EP3466666A1 - Device for compression drawing of flat fibrous material - Google Patents

Abstract

Device for compression drawing of flat fiber material, comprising a longitudinally movable guided punch (121, 221, 521) with a punch guide cylinder (126, 226), and a fold holder (123, 223, 523) with a Faltenhalterführungszylinder (124, 224), in a a pleat holder guide bush (104, 204) connected to a frame (108, 208, 508) is longitudinally movable, the plunger symmetry axis and the pleat holder symmetry axis having the same position, the pleat holder guide bushing for forming a pleat holder stator (112a, 212a) with at least one first pleat holder actuator element (118, 218), said pleat-holder guide cylinder is integrally connected to at least one second pleat-holder actuator element (119, 219), said pleat-holder stator and said pleat-holder rotor forming a pleat-holder drive, said plunger guide bush (106, 206) for formation a stamp st Ator (110a, 210a) is integrally connected to a first stamp actuator element (116, 216), the stamp guide cylinder (126, 226) for forming a punch rotor (110b, 210b) with a second stamp actuator element (117, 217) is integrally connected, wherein the Stamp stator and the stamp runner form a punch drive, wherein the Faltenhalterstator (112a, 212a) immovably connected to the frame, and wherein the stamp stator (110a, 210a) immovably to the frame (208, 508) is connected or integral with the Faltenhalterführungszylinder (124 ) is connected and the Faltenhalterführungszylinder (124) at the same time forms the punch guide bush (106) in which the punch rotor (110b) is mounted longitudinally movable.

Description

The invention relates to a device for compression drawing of flat fiber material, comprising a punch, which is designed for cooperation with a drawing die in a forming process, and a fold holder, wherein the punch is longitudinally movably guided with a degree of freedom for movement in or parallel to a stamp symmetry axis the pleat holder comprises a pleat holder guide cylinder adapted to cooperate with a pleat holder guide sleeve such that the pleat holder is longitudinally movably guided with one degree of freedom for movement in or parallel to the pleat holder axis of symmetry, the movement being relative to a frame, and at least the pleat holder guide sleeve fixed to movement Frame is connected. If the pleat holder is designed as a segmented pleat holder, it also has only one pleat holder symmetry axis, which is considered to be arranged in the center or in the case of a circle deviating contour in the center of gravity of all segments of the segmented pleat holder.

The compression drawing of flat fiber material is particularly suitable for the production of three-dimensional molded parts. The use of fiber material for molded parts has been known for a long time, but because of the lack of quality of known and applied methods, it has become a niche existence without wider application. In the meantime, compression forming has been used to develop a process that makes it possible to produce molded parts of higher quality. In contrast to compression molding, the blank is clamped when pulled. This results in greater potential applications: Without a need for post-processing or lamination to mask quality defects, more cost-effective molded parts can be produced. These are now often used as packaging.

The transformation of plastics or metals on the one hand and the transformation of fiber material (hereinafter exemplified by cardboard) on the other hand differ fundamentally from each other, that despite any external similarities between deep drawing of sheet metal, thermoforming of plastic films and compression drawing of fiber materials, a transfer of technological solutions not is possible.

The transformation of plastic films and semifinished products to 3-D moldings is carried out by the thermoforming process, which is often misunderstood in practice with the term thermoforming. The thermoforming of plastics is based on the heating of the material to a temperature in which the material has a pronounced flow behavior. The material is fixed on all sides and then drawn out of its thickness into the mold with the help of its plastic deformability (primarily elongation in the range of 30 - 300%). For this purpose, fluidic pressure media (compressed air, vacuum) are usually used, possibly pre-stretched with a punch. The final shape is always formed by the pressure medium. The material is controlled to selectively reach its flow state preheated and cooled in the tools to solidify again.

However, the definition of thermoforming as such includes, unlike thermoforming, forming from a flat blank without a targeted change in thickness. Accordingly, both processes are technologically fundamentally different and also subject to the implementation in machines according to different conditions.

For this reason, in particular conventional thermoforming machines and the pursued technological solutions for the forming of plastic films are not suitable for the forming of cardboard by compression drawing. In particular, paperboard does not show any pronounced flow behavior, in particular not with multiaxial stretching. Even with specially equipped special qualities only strains of 2 to 12% can be achieved.

The deep drawing of sheet metal is from the basic point of view, the compression drawing of cardboard more similar than the thermoforming. When deep drawing sheet metal, a flat blank, the blank, clamped with a hold-down and applied a defined force. The stamp usually pulls the material cold into the drawing ring. Due to the state of stress, flow sets in the material, which compensates for the geometric excess of material. The material is only used up to the yield point, so that wrinkles and tears are prevented. The drawing gap (between the punch and the drawing ring) is greater than the material thickness. The surface contact with the drawing ring is dissolved immediately after deformation in order to avoid the extremely high friction further.

Although the compression drawing of cardboard is in the arrangement of tools and superficially similar to the deep drawing of metal, since in both cases, a clamping of the blank before the drawing process takes place. The procedures differ However, it is essential in the material, in the physical effects and not least the machine requirements. The flat carton blank is acted upon by a fold holder with a defined force and the punch pulls the carton in a Ziehbüchse whose gap - this is a serious difference to the deep drawing of metal - is less than the thickness of the punch. The material, which is not flowable unlike metal, causes wrinkles which are not prevented during compression drawing but are a characteristic part of the process. The thermally assisted compression in the direction of thickness of the material in the drawing box immediately after passing through the forming radius, from which the name of the method originates, fixes the folds and ensures the dimensional stability of the moldings. The wrinkles extend to below the fold holder and ensure a strong thickening with higher molding.

Dehydration of the fiber material is a central task in compression drawing to achieve new bonds in the cellulosic fibrous structure and minimize shape deviation. These are the Ziehbüchse and their exposure to the molded part under compression of importance.

The shrinkage of the material usually leads to adhesion of the molding to the stamp, which leads to the need for a technical stripping solution.

The inhomogeneity, anisotropy and hygroscopicity of the material as well as the compression in the thickness direction as a specific process basis make a completely different working method of compression drawing machines, based on the specific material behavior, necessary. The adoption of peculiarities and solutions from the more remote areas thermoforming or deep drawing of metal is generally not possible despite purely external similarities and does not take place in practice.

The hitherto very frequently practiced production of 3-D molded parts made of fiber material such. B. Cardboard is mainly used in packaging technology and is limited to embossing geometries or low value added applications such as ready meals or cheese boxes with a simple geometric spectrum. Recently, carton compression drawing techniques have enabled a much wider range of geometries while substantially improving the quality of the molded articles.

This is how the document describes DE 10 2013 107 932 A1 a method for three-dimensional forming of sheet material such as natural fibers, especially paper or cardboard, by compression drawing, here referred to as deep drawing. It is also provided that a bottom of the molding is calibrated or stamped during manufacture, that the material is moistened and heated before, during or after the forming. The aim of this is to increase the suppleness of the material, resulting in the formation of very small wrinkles. In addition, a previously moistened cut of fiber material is easier to reshape. In addition, if necessary, a subsequent expansion of the cylindrical mold body is provided, if the ultimately desired shape deviates from the cylindrical shape.

The publication DE 10 2013 107 931 A1 describes a very similar method, but the sheet material is not present as a blank, but this is made only in a preliminary step of a roll of material.

In packaging machines (molding machines or molding, filling or forming, filling and sealing machines), such a known method in its previously described, further developed form, however, because of the peculiarities of the fiber material, which is in conflict with the required machine performance, not applicable.

For a clocked mode of operation concepts are already known to integrate the method. The clocked operation is based on the Stempelhubbewegung and the time required for it and was previously considered in the compression drawing as given. In the consumer goods industry, where such packaging machines are regularly used, however, the highly effective and thus high-speed-oriented mode of operation of machines is required in order to economically design the process and thus also the production of molded cardboard parts economically. Previously conceivable and desired performance ranges are 60-150 cycles (molded parts per minute), but this contradicts the procedural peculiarities, in particular the time required for compression drawing of fiber-based materials (paper, cardboard, paperboard, nonwovens, possibly in structural or layered composites with polymers) with new high molding qualities.

Specific requirements of the method, which can limit the rapid operation in the context of a process management, as implemented in the prior art, are the rapid introduction of a sufficient amount of heat energy and the loading of the container wall with sufficient compression pressure for sufficient compression to the To allow new formation of bonds in the cellulose-based material. The resulting high accuracies for the gap between drawing die and punch, their necessary exact coaxiality and the correspondingly high demands on the rigidity of the tool assembly lead to a massive construction of the forming, the corresponding massive construction of the machine with the attendant disadvantages for the Dynamics leads.

Also known is a forming in several stages with reshaping by spreading, stretching or by pre- and / or downstream embossing individual regions or zones of the molding. It may be advantageous to provide an upstream or intermediate conditioning by supplying heat energy and / or moisture.

It is a very frictional process. The properties of the slightly rupturing, hygroscopic and inhomogeneous material with low intrinsic strength require gentle forming, which is made difficult in high-speed machines by correspondingly high accelerations, inertia and resulting vibrations. This particular limits discontinuous procedures, as they are required for the forming in several stages with reshaping by spreading, expansion or by pre and / or downstream embossing of individual regions of the molding, limits.

The object of the device according to the invention is to minimize the size of the forming unit as the core element of a continuous machine such that the entrainment of multiple running, in particular similar forming units on a rotary, possible and the spatial freedom for inserting and centering the blank when engaging two rotary in one another is created and at the same time the high demands on the accuracy of the tool movements to each other and the rigidity of the arrangement are met with minimal tendency to clamp.

The object of the invention is achieved by a device for compression drawing of flat fiber material, comprising a punch with a stamp symmetry axis, designed to cooperate with a drawing die in a forming process, and a fold holder with a Faltenhaltersymmetrieachse. The fold holder presses the flat fiber material against a base plate, is introduced into the draw die. As a result, the fiber material with defined bias and especially adjustable wrinkling is formed.

As an alternative to the solution of the known from the prior art spaced drives the drives of the fold holder and stamp are arranged coaxially according to the present invention, wherein z. B. one of the drives, in particular the Faltenhalterantrieb having a hollow rotor, in the interior of the punch drive finds room. For the compression drawing operation, the pleat holder drive then has to apply a force which corresponds to the sum of the pulling force and the pressing force of the pleat holder. In this solution, a single and moreover less rigid guidance of the pleat holder is sufficient, since no eccentric force on the pleat holder by outside of the axis of symmetry arranged, therefore particularly stiff and difficult running guides must be compensated. This also represents a major advantage, as it makes the device lighter, cheaper and at the same time functionally reliable.

The punch has a punch guide cylinder adapted to cooperate with a punch guide bushing such that the punch is longitudinally movably guided with one degree of freedom for movement parallel to the punch axis without tilting or jamming. As a result, the stamp moves exactly on the drawing die and ensures a precise forming process.

The pleat holder includes a pleat-holder guide cylinder configured to cooperate with a pleat-holder guide bushing such that the pleat-holder is longitudinally movably guided with one degree of freedom for movement parallel to the pleat-holder axis of symmetry without tilting or pinching. The movement is provided relative to a frame and at least the fold holder guide bush is immovably connected to the frame, ie it is only detachable by disassembly with appropriate design and otherwise firmly connected.

According to the invention, it is provided that the fold holder guide bush is integrally connected to at least one first fold holder actuator element and together with this forms a fold holder stator. The pleat-holder guide cylinder is integrally connected to at least one second pleat-holder actuator element and together with it forms a pleat-holder rotor. The Faltenhalterstator and the Faltenhalterläufer are provided for cooperation as a Faltenhalterantrieb.

The punch axis of symmetry and the pleat holder axis of symmetry are identical, have the same location, orientation and course, that is to say the pleat symmetry axis. H. the entire device for compression drawing has in its essential parts on a coaxial structure. This is especially true in a rotationally symmetrical structure. In the case of a segmented pleat holder, the decisive axis of symmetry is formed by the totality of the segments, i. H. with a round contour, in its center or with an asymmetrical contour in its center of gravity. In the context of the invention, a match of the axes of symmetry is in essence also an exact match, it is not limited. Because, especially with an asymmetrical contour, there may be functional reasons for allowing a deviation here. This is for example in over the circumference of a stamp with unsymmetrical contour different pulling forces during compression pulling. This may require an approach of pulling forces at a different center of gravity than the static center of gravity of the contour in question.

A preferred embodiment provides that the Faltenhalterstator is immovably connected to the frame. The stamp stator is integrally connected to the fold holder guide cylinder, both together form an element. The folding holder guide cylinder thus forms at the same time the punch guide bush in which the punch rotor is mounted longitudinally movable. Because the hollow, hollow-cylindrical, rotationally symmetrical cross-section, folding holder guide cylinder has the required actuator elements on its inner wall, it can serve as a stamp stator.

It is further contemplated that the stamp as a conventional electromechanical axis with a mechanical transmission path, z. B. a spindle drive, as well electric spindle-nut linear axis, is combined with a fold holder described above as a direct drive. Such a drive imparts a greater force than a direct drive as described below, but is disadvantageous in terms of poorer dynamics. During the compression drawing, however, there are no increased dynamic requirements for the punch drive, in contrast to the regulation of hold-down force profiles. As a compromise solution, an "indirect" linear drive as a punch drive is possible in which a transmission between the linear drive and punch is inserted, which transmits the drive energy of the linear drive to the punch.

Alternatively, the punch guide bushing is integrally connected to a first stamp actuator element and together with this forms a stamp stator. An actuator element is a subelement of an actuator, for. B. the winding or at least one permanent magnet of an electric drive or a piezoelectric element. The punch guide cylinder is integrally connected to a second punch actuator element and forms together with this a punch rotor, wherein the punch stator and the punch rotor are provided for cooperation as a punch drive.

This combined drive variant, in which the roll holder also forms the stamp stator or both are integrally connected, entails complications in the adjustment of the pleat holder force. The plunger force as a reaction force from changes in shape and friction forces must either be well known, although it varies, for example, with the process variables and the material used. It represents a "disturbance variable" on the wrinkle holder control, which must be included as an expected value in the control.

The energy consumption is significantly higher, since the fold holder drive must always apply the force of the punch in addition to the Faltenhalterkraft. The increased energy requirement also leads to additional problems with the heat dissipation in the Faltenhalterantrieb due to the associated high ohmic winding power loss.

Since the Faltenhalterantrieb must apply the sum of the folding holder force and hold-down force, it is to be expected, given a limited space, that the realizable punch force is significantly smaller than in a punch drive, the which is supported directly on the frame. The plunger holder drive, in addition to the punching force, must apply either the full weight or, during the drawing process, part of the weight of the punch drive, resulting in additional power losses in the plunger holder drive.

In any case, such a scheme is much more complicated than with a separate drive solution fixed to the frame connected stator of stamp and fold holder. However, the advantages lie in less effort in the structure, an even clearer structure and a minimum space requirement.

In general, the main advantage of a magnetic direct drive as an integrated drive in the fold holder is that no transmission path (eg threaded spindle or uniformly or unevenly translating gear) from the drive to the tool is required. This reduces disturbances of the control, which are caused by friction (up to self-locking in threaded spindles) or play. The entire arrangement can thus work much more directly and dynamically.

Another coaxial drive solution provides that both punch drive and Faltenhalterantrieb are connected to the respective stator to the frame, so that the forces that occur during clamping and pulling, directly over the frame are derived. In this alternative embodiment, the stamp stator and the Faltenhalterstator are arranged in the axial direction one behind the other and immovably connected to the frame. They can also be connected to each other at the end faces.

The punch guide cylinder is mounted in this embodiment, both within the punch guide bushing and, according to a preferred embodiment, at the same time longitudinally movably within the pleat holder guide cylinder. The latter is not mandatory.

Alternatively, the stamper stator and the Faltenhalterstator are arranged in the same plane and the coupling of the Stempelstators to the frame via the Faltenhalterführungsbuchse by at least one coupling element between the stamp stator and Faltenhalterführungsbuchse is passed through at least one recess in the Faltenhalterläufer, the recess in the axial direction at least carried out so long that an unobstructed stroke of the pleat holder is made possible. Preferably, three coupling elements between the stamp stator and the fold holder guide bushing and correspondingly three recesses in the fold holder runner are provided. The coupling of the Stempelstators to the frame is arranged in this case within the Faltenhalterantriebs, which is why in this case not only its radially outer actuator element, but also the radially inner actuator element must be at least partially hollow or with recesses.

It has proven to be advantageous if the punch is guided at least within the guide cylinder by a rolling or sliding bearing. As alternatives to offer also guide gear or spring guides. The same applies to the leadership of the wrinkle holder.

The guide of the stamp can be designed so that the stamp during the entire course of movement or only on a first part of its course of movement and before immersion in the drawing die in the stamp guide bushing is performed. If the guide is only on one part, then the die takes over the further guidance as soon as the punch is immersed in it.

The punch drive or the fold holder drive is preferably designed as an electric linear drive. Both drives can be designed as electrical linear drive. As an example, piezoelectric actuators come into consideration, the applicability is highly dependent on the size. Screw drives, toothed racks or similar mechanically based drives are also possible.

In that case, it has proven favorable if the first punch actuator element and the first fold holder actuator element are each designed as at least one winding and the second punch actuator element and the second fold holder actuator element are each designed as at least one permanent magnet or vice versa. One or both of the main elements of electrodynamic actuators, in this case the first and the second punch actuator element and the first and the second fold holder actuator element often also include, in addition to the combination of winding and permanent magnet, in order to increase the force compared to the so-called ironless versions soft magnetic sections for guiding the magnetic flux. These are commonly referred to as soft magnetic flux guides or anchors.

The aforementioned electrical linear direct drives are designed according to an advantageous embodiment as at least single-phase moving magnet drives, at least single-phase moving coil drives or at least single-phase moving iron drives. In this case, a moving magnet drive means a drive with at least one moving permanent magnet (magnetic rotor), a moving coil drive a drive with at least one moving coil (reel rotor, Tauchspulantrieb) and a moving iron drive a drive with at least one moving soft magnetic flux guide (iron runner, armature).

An advantageous embodiment of the invention therefore comprises stamp actuators and / or Faltenhalteraktoren, in which an actuator element is designed as a soft magnetic flux guide (armature) and the other actuator element has at least one winding. This makes it possible to build particularly robust constructed electromagnetic actuators with moving iron, but have a lower energy density and lower controllability than the permanent-magnet drives.

The soft-magnetic flux guides can be designed, for example, as a core, yoke, pole piece or yoke. The use of such soft magnetic flux guides known in the art are included in the invention, although not expressly mentioned in connection with the punch actuator elements and the fold holder actuator elements.

In order to realize a correspondingly powerful and to the extent controllable drive, it has proved to be advantageous that the electric linear drive in the narrow space between the fold holder guide bushing and Faltenhalterführungszylinder high-energy rare earth magnets comprises. In particular, sintered neodynium-iron-boron magnets with the highest possible energy density or sintered samarium-cobalt magnets which can be used at higher temperatures are considered.

Advantageously, the guide between the Faltenhalterführungszylinder and the Faltenhalterführungsbuchse and / or between the punch guide cylinder and the punch guide bush as Wälzführungen or highest Precision requirements also as aerostatic guides, so-called air bearings, or especially designed for small travel distances as spring guides.

Special advantages promises an integrated directly in the magnetic circuit of stamp stator and stamp runner and / or the magnetic circuit of Faltenhalterstator and Faltenhalterläufer roller guide. The result of such a solution is maximum compactness, good controllability due to the friction conditions in the rolling guide and, above all, smaller moving masses and thus higher dynamics than with separate attachment of the rolling guide to the drive. Such an integration of the Wälzführung in the magnetic circuit of the drive is also possible with other linear actuators and not limited to the linear drives between the stator stator and stamp runner or of Faltenhalterstator and Faltenhalterläufer.

It is particularly advantageous if the electric linear drive comprises a control device which has a position-controlling or position-controllable control, for example a cascaded or a flatness-based control, or a force-controlled or force-regulating or a force-controllable or a force-controlling or force-controlled or a force-controlled Control enabled.

In principle, a position control, for. B. the punch drive, or a controlled closing of the fold holder in the direction of the base plate possible until the force increases and the control device switches to control the Faltenhalterkraft. A flatness-based control must m.E. not explicitly mentioned, this is a variant of a position control. Another, previously widespread variant of the position-regulating control is the so-called cascade control. Position regulating or controlling control is conceptually more precise, since the actual drive, but not the control position is controlled. The same applies to the terms of the force-controlled or the force-regulating or the force-controlling or force-controllable control.

Thus, for example, the pressure force of the pleat holder can be adjusted and continuously adapted to the respective requirement over the drawing process. Particularly important are these options for control in the event that the runner of the fold holder is also the stator of the punch. Then the fold holder drive must apply in addition to the platen holder force and the punch force in the frame derived. In order to always have optimum forces acting on punch and plunger holder, an accurate control and regulation of the drives is required.

The advantages of this direct arrangement are the high dynamics and the avoidance of a transmission path with the associated interference potential. The force curve over the punch position at the fold holder must be matched to the drawing gap, the inlet radius and the material. Due to the inhomogeneity of the material intended for compression drawing, there is a transitional area with risk of cracking. The approach to this transitional area is necessary in the interest of optimum drawn part quality. However, a crack at the randomly distributed material vulnerabilities must be avoided. Force peaks when switching from position to force control slow down the cycle; inadequate control dynamics can not implement the curve sufficiently well in the cycle time of approx. 0.1 ... 0.2 sec.

As an advantageous embodiment, a one-piece fold holder, preferably with only one Faltenhalterantrieb provided.

As a further advantageous embodiment, a segmented fold holder with a plurality of segments, which are independently controllable at least in groups, each with its own fold holder drive, is provided. It is a total or segmentally force-controllable or force-controllable, alternatively position-controlled control provided, which in particular also exerts over the course of the compression pulling operation variable folding force. In the case of the segmented fold holder, each segment has a separate, individually controllable first fold holder actuator element and second fold holder actuator element.

As a result, different areas of the flat fiber material can be clamped with different intensity between the base plate and the fold holder. This is particularly advantageous in non-circular cross-section of punch and drawing die.

Furthermore, a segmented fold holder is provided, which exerts a segment-wise, spatially resolved, force-controllable or force-controllable, time-resolved, fold-holding force variable over the course of the compression drawing process. The The first Faltenhalteraktorelement and the second Faltenhalteraktorelement are executed segmented in the case.

Alternatively, fold holder segments are provided, which are arranged on the blank of a molded part facing surface fold holder and provided for contact with the blank, wherein the fold holder segments are movable relative to the fold holder by means of Faltenhaltersegmentantrieben. The Faltenhaltersegmentantriebe are small direct drives, which can then be arranged and active in different numbers and arrangement, in particular depending on the geometry of the blank used. This can vary widely with the same footprint.

In the case of a segmented fold holder, the specific property of the fiber material intended for processing can be better taken into account, which ensures that the material load or the loadable material load is dependent on the fiber orientation. Therefore, a subdivision of the basic shape of the pleat holder into areas, which are provided for contact with regions with the same fiber orientation, in order to keep the stress in the fiber direction always constant. This also leads to an avoidance of deviations in shape due to the fiber-directional load. By means of the segmentation of the pleat holder, dynamic pressure regulation between different segments can be achieved on the basis of the material behavior expected below the segment. The type of wrinkling changes dynamically between the segments according to the pressure gradients with effect on the fiber material to be formed. With the help of the proposed segmentation of the pleat holder, especially complex components with a specially shaped cavity should be able to be realized.

Due to the segmentation, the design of the force requirement can be adapted exactly to the respective needs of the fiber orientation in each case. This avoids having to design the drives or a single drive of a pleat holder without segmentation excessive.

To reduce the number of individual drives, individual segments, which are provided for different areas, but with the same fiber orientation, be mechanically rigidly interconnected via segment bridges. The segment bridges are preferably led outside.

The use of electrical linear direct drives for decentralized pressure control, depending on the fiber orientation, takes place with the required high dynamics. For this purpose, the electrical linear direct drives are preferably designed as at least single-phase moving magnet drives, at least single-phase moving coil drives or at least single-phase moving iron drives. In this case, a moving magnet drive means a drive with at least one moving permanent magnet (magnetic rotor), a moving coil drive a drive with at least one moving coil (reel rotor, Tauchspulantrieb) and a moving iron drive a drive with at least one moving soft magnetic flux guide (iron runner, armature).

The individually driven and moved segments may also have different surface properties (e.g., coating, textures, etc.) according to the grain direction. Thus, the surface can be adapted to the requirements of the material used in each case, for example with regard to the desired friction.

In the preferred embodiment, the segmented fold holder has such a construction that the regulation of the pressure on the fiber material is realized by at least one moving-magnet drive, at least one moving-coil drive or at least one moving-iron drive becomes. The same applies to the delivery of the material in the forming zone between two transformations. Here, larger Faltenhalterhübe may require depending on the geometry of the Umformteils. Unless larger strokes than 20 mm are required, single-phase direct drives can be used. The exact lift dimension depends on the concrete design, under certain circumstances 25 or even 30mm stroke can be realized with single-phase direct drives.

For larger strokes, multiphase direct drives or a serial arrangement of a slow feed drive (eg spindle) and a quickly controllable direct drive are provided. The drive can alternatively also take place indirectly via a drive deflected by means of a lever drive.

A particularly large stroke requires maintenance and assembly movement of the entire pleat holder. This is in a preferred embodiment by a Toggle construction realized. Their drive can be carried out both electro-mechanically and electro-pneumatic (pneumatic drive).

The segmentation develops particular advantages in the setting of a defined pressure curve in the contact surface between the fold holder and blank of the molded part. In order to realize this in a conventional manner, either numerous transmission elements and a constructive structure with a strongly fissured structure are required. As a result, interventions, z. As for retrofitting or maintenance, impossible, but at least ineffective. Ultimately, this also leads to high production costs and because of the numerous components.

In the present invention, however, the flexibility of driving active elements, possibly also on an elastic or partially elastic Faltenhalterplatte, does not interfere with the machine structure and are not visible. In addition, a surface pressure pattern can also be specified depending on the shape and format change without having to completely change the machine structure. These features are ideal for a machine platform.

Further advantages arise when the punch drive can be controlled in such a way that a vibration superimposed compression pulling is executable. As a result, the molding of the fiber material is supported in the die.

Further advantages result from a demolding device, which is designed as a cutting device and combined with a wiper edge. The punch drive is controllable in a forward movement and a backward movement, so that the punch is withdrawn dosed after the molding process.

An alternative solution for demolding the molded part formed from the fiber material, which adheres in the die or on the stamp, is a demolding device, which can exert media pressure on the molded part. The media pressure must be fed via the stamp into the area between the stamp base and the molded part. Another solution is to apply a vacuum to the molding to peel it off the stamp. Alternatively, an ejector may be provided which ejects the molding from the die.

A particularly advantageous solution provides that the media pressure is not supplied, but is generated in the stamp itself. This is done by a plunger, which is longitudinally movably driven in a bilaterally open air passage in the interior of the punch. The media pressure, here the compressed air, can be discharged from an air outlet opening at a bottom of the punch. The drive of the plunger ram is preferably carried out by a linear drive, for example by an electric linear drive. Such a linear drive is designed so that the plunger can be moved up and down in the air duct, in particular by the proposed drive. The plunger is sealed against the wall of the air duct, so that the air compressed in front of the plunger plunger can only leave the air duct via the air outlet opening.

An alternative to this is provided by a driven die tappet. The vacuum is caused by a die tappet which is longitudinally moveable in the draw die. Instead, it is also possible that the die tappet is controllable as an ejector. The drive of the die tappet has a similar structure to that of the die tappet. An ejector actuator element is controllable and interacts with the die tappet, in particular a second actuator element provided there, for example a permanent magnet, if the ejector actuator element is designed as one or more windings.

It has also proved to be advantageous if at least the head of the punch and the drawing die are completely thermally insulated from the frame. Then, a heating of the stamp can be made to z. B. to dry the formed material and thus fix it in the newly obtained form. But above all, the insulation is suitable to minimize unwanted and uncontrolled heating and the associated undesirable effects, especially the thermal change in length. The external heating of the direct drives, for example via the fold holder, must be prevented. The pleat holder heats to some extent during each cycle and also heats up enough to reach temperatures that are problematic in terms of occupational safety.

The aim of the device according to the invention is to minimize the size of the forming unit as a core element of a continuous machine in such a way that it is possible to carry multi-stage forming units on a rotary machine.

In addition, for the insertion and centering of the blank when engaging two rotary in one another corresponding spatial freedom is required, which is ensured by the new Faltenhalterlösung. Despite its reduced size, the unit must be so resistant to tension, pressure and torsion that the required accuracies are guaranteed within the forming unit, even at maximum process forces, which can be considerable in the compression of cardboard. It is a modular exchange possible and minimized the burden of the rotary.

In the case of a non-segmented pleat holder, the device according to the invention has only one drive for the pleat holder, while according to the state of the art two synchronously running drives were provided which were intended to ensure an absolutely necessary uniform contact pressure of the pleat holder on the blank. However, distortions due to possible asynchronisms of the two drives are recorded, which are typical in the use of electrical drives, because small differences in position during the motion processes always creates a deviation. Even the slightest deviation can lead to high stresses on the mechanism, which then lead to the loss of parallelism and thus the uniform force distribution when clamping the pleat holder, but at least to increased bearing load and thus increased wear.

Of particular great influence on the space savings and the improved stability of the stamp, which is centrally stabilized in the preferred embodiment in the form of an integrated guide together with the fold holder and does not require a separate guide carriage, as is the case with known solutions. The punch can be performed directly in the inner part of the guide bush, for example by a rolling or sliding bearings or only by the guide bush itself. For this it is advantageous if they z. B. made of brass. The solution of the invention, the stamp is supported friction.

The support can be limited to the first part of the course of movement of the stamp. This results in a short cylindrical guide surface and consequently a low height of the entire unit. However, when the punch leaves the guide or support surface as it moves, it must be ensured that it is reinserted into the guide bushing on the return stroke. Alternatively, the punch is designed so long that the guide or support is maintained throughout the entire punch stroke, which For example, by a correspondingly longer design of the stamp is possible. In this case, the whole unit builds up a bit higher.

The entire forming unit is preferably modular and can be disassembled and replaced separately from the other units of the rotary.

• Fig. 1: eine schematische teilgeschnittene Darstellung einer Ausführungsform einer erfindungsgemäßen Kompressionszieheinheit;
• Fig. 2: eine schematische teilgeschnittene Darstellung einer weiteren Ausführungsform einer erfindungsgemäßen Kompressionszieheinheit;
• Fig. 3: eine schematische geschnittene Darstellung eines Stempels einer Ausführungsform einer erfindungsgemäßen Kompressionszieheinheit;
• Fig. 4: eine schematische geschnittene Darstellung einer Ziehmatrize einer Ausführungsform einer erfindungsgemäßen Kompressionszieheinheit;
• Fig. 5: eine schematische geschnittene Darstellung einer weiteren Ausführungsform einer erfindungsgemäßen Kompressionszieheinheit; und
• Fig. 6: eine schematische Draufsicht eines Faltenhalters einer weiteren Ausführungsform einer erfindungsgemäßen Kompressionszieheinheit.

Further details, features and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

• Fig. 1 : a schematic partial sectional view of an embodiment of a compression draw unit according to the invention;
• Fig. 2 : a schematic partial sectional view of another embodiment of a Kompressionszieheinheit invention;
• Fig. 3 FIG. 2 is a schematic sectional view of a stamp of an embodiment of a compression draw unit according to the invention; FIG.
• Fig. 4 FIG. 2 is a schematic sectional view of a drawing die of an embodiment of a compression drawing unit according to the invention; FIG.
• Fig. 5 a schematic sectional view of another embodiment of a compression draw unit according to the invention; and
• Fig. 6 : A schematic plan view of a folding holder of another embodiment of a compression draw unit according to the invention.

Fig. 1 shows a schematic sectional view, except for the punch, an embodiment of a Kompressionszieheinheit 100, are arranged coaxially in the punch drive 110 and Faltenhalterantrieb 112, wherein the Faltenhalterantrieb 112 has a hollow, in particular hollow cylindrical Faltenhalterläufer 112b, in the interior of the punch drive 110 with its punch rotor 110b takes place. In this case, the Faltenhalterläufer 112b of the Faltenhalterantriebs 112 is integrally connected to the punch guide bushing 106 of the punch 121 and at the same time forms the punch stator 110a of the punch drive 110. The same component serves as Faltenhalterführungszylinder 124 of the folding holder 123 and is therefore connected to this frontally. The punch rotor 110b of the punch drive 110 simultaneously represents the guide cylinder 126 of the punch 121. Guide cylinder 126 and punch 121 are both connected to each other at the front.

For punch drive 110, the stamp stator 110a has a first stamp actuator element 116, here embodied as a winding, and a second stamp actuator element 117, here designed as a permanent magnet. For the fold holder drive 112, a winding is also provided as a first fold holder actuator element 118 and a permanent magnet as a second fold holder actuator element 119. Between the respective first and the second actuator element, the desired, controllable force effect of the drives unfolds.

For the compression drawing operation, the pleat holder driver 112 then has to apply a force corresponding to the sum of the pulling force of the punch 121 against the drawing die 122 and the pressing force of the folding holder 123 against the base plate 109. For this purpose, an electronically coupled control of both drives, the punch drive 110 and the fold holder drive 112, is required. This arrangement offers a particularly small space, especially a low height.

For a compression drawing process, a blank of flat fiber material is inserted into the gap between the base plate 109 and the fold holder 123, for which purpose the punch 121 must be moved so far upwards that this gap is freely accessible. Thereafter, the pleat holder 123 is moved by the pleat holder driver 112 in such a manner that the pleat holder 123 presses against the base plate 109 and exerts a defined clamping force on the blank. Thereafter, the punch driver 110 is activated and moves toward the drawing die 122, drawing the blank, which is tensioned by the pressing force of the folding holder 123, under compression into the drawing gap between the punch 121 and the drawing die 122. In this case, it is necessary to readjust the clamping force of the pleat holder 123 constantly, since the force to be applied by the pleat holder drive 112 corresponds to the sum of the clamping force of the pleat holder 123 and the pulling force of the plunger 121. This is due to the fact that only the Faltenhalterantrieb 112 can divert forces directly into the frame 108, while the punch drive 110 can derive the forces only indirectly via the Faltenhalterantrieb 112. This requires a suitable control and a suitable drive concept, particularly suitable for this purpose is a linear motor. But there are also other drives, especially those with a mechanical lock, suitable. For this purpose, spindle drives, racks or the like come into consideration.

The coaxial design of the compression drawing device according to the invention can be recognized by the superimposed axes, the stamp symmetry axis 130 and the folding holder symmetry axis 132.

Fig. 2 shows a schematic and, apart from the punch, cut view of another embodiment of a compression draw unit 200 according to the invention with a further coaxial drive solution. This provides that the punch drive 210 with the punch stator 210a and the fold holder drive 212 with the fold holder stator 212a are each fixedly connected to the frame 208, so that the forces that occur when clamping in the fold holder 223 and during the compression drawing of a blank are immediately (resp ., Via a fixed connection between stamp stator 210a and fold holder stator 212a), but above all without moving parts in the force path, via the frame 208 are derived.

The fold holder 223 is connected to the guide cylinder 224, which also serves as a runner 212b of the fold holder drive 212. The guide cylinder 224 is designed as a hollow cylinder, so that in its interior the punch 221 or its punch guide cylinder 226 is longitudinally movably storable. The Faltenhalterstator 212 a of the Faltenhalterantriebs 212 is directly connected to the frame 208 or, as shown here, with the Faltenhalterführungsbuchse 204 frontally fixed.

The stamp drive 210 comprises the stamp stator 210 a, which at the same time comprises the guide bush 204 and is connected directly to the frame 208. The stamp runner 210b at the same time forms the stamp guide cylinder 226 of the punch 221. The procedure of the compression drawing operation when the punch 221 dips into the drawing die 222 and the function of the drives correspond to that Fig. 1 described.

For the punch drive 210, a first punch actuator element 216, implemented as a coil, and a second punch actuator element 217, implemented as a permanent magnet, act together. The same applies to the fold holder drive 212 with a first fold holder actuator element 218, designed as a winding, and a second fold holder actuator element 219.

This embodiment simplifies the force regulation, since each of the two drives 110, 112 is separately controllable and unaffected by the other. It must but a larger height can be accepted. The stamp symmetry axis 230 and the fold holder symmetry axis 232 overlap one another, because the inventive apparatus for compression drawing also in the embodiment according to FIG Fig. 2 is constructed coaxially.

In these solutions, as they embody the embodiments described above, a single guide with low stability requirements, since no eccentric force on the pleat holder must be compensated.

Fig. 3 shows a schematic sectional view of a punch 121, 221 of an embodiment of a compression draw unit 100, 200 according to the invention. The punch 121, 221 has in its interior a cylindrical air duct 304, which is equipped with a plunger 310. The plunger 310 cooperates with the air duct 304 so that in the gap between the wall of the air duct 304 and the plunger 310 no air can flow past. Inevitably, an air pressure builds up in front of the plunger 310 when it moves longitudinally in the air channel 304.

This effect is used in order to press off a molded part from the punch 121, 221 with the air pressure present at an air outlet opening 306. For this purpose, the movement of the plunger 310 must be controllable. The drive of the plunger 310 is effected by a compressor actuator element 216, for example a winding, which cooperates with a corresponding actuator element (not shown) in the plunger 310 and causes the movement.

Fig. 4 1 shows a schematic sectional representation of a drawing die 122, 222 of an embodiment of a compression draw unit 100, 200. In the recess of the drawing die 122, 222, a die tappet 410 is arranged longitudinally movable and drivable by the ejector actuator element 416. This acts together with a further actuator element in the die tappet 410 so that there is a controllable movement of the die ram 410. This can be used to either create a vacuum in the recess of the drawing die 122, 222 and thereby withdraw the molding from the punch or the die tappet 410 serves as a mechanical ejector and ejects the in the recess of the drawing dies 122, 222 clamping molding.

Fig. 5 shows a schematic sectional view of another embodiment of a compression draw unit 500 according to the invention. Both the punch 521 and the fold holder 523 with their symmetry axes 530, 532 are driven relative to the frame 508. The punch drive 510 and the fold holder drive 512 serve this purpose. The punch 521 is shown in a deflected illustration and sinks into the pull dies 522. In this case, a molded part 505 is formed.

Its blank is clamped by the fold holder 523. This has a special design, because next to the means of the Faltenhalterantrieb 512 driven pleat holder 523 are pleat holder segments 524 in direct contact with the blank of the molding 505. Each individual Faltenhaltersegment 524 is opposite the Faltenhalter 523 driven, to which the Faltenhaltersegmentantriebe 513 serve. As a result, the clamping of the blank can be varied particularly well and adapted to local requirements as well as a change in the clamping force over the course of the forming process is possible.

Fig. 6 shows a schematic representation from above of a folding holder 523 of another embodiment of a Kompressionszieheinheit invention. Concealed behind the pleat holder 523, the pleat holder segments 524 are shown. Each pleat holder segment 524 has two pleat holder segment drives 513 that allow for uniform movement and force of each pleat holder segment 524. The preferred combination of pleat holder 523 and pleat holder segments 524 provides high dynamics with sufficient stroke of the entire assembly.

LIST OF REFERENCE NUMBERS

100, 200

Compression drawing unit

121, 221

stamp

122, 222, 522

drawing die

123, 223, 523

blank holder

104, 204

Blank holder guide bush

106, 206

Punch guide bushing

108, 208, 508

frame

109, 209, 509

baseplate

110, 210, 510

punch drive

110a, 210a

Stempelstator

110b, 210b

Stempel runners

112, 212, 512

Fold holder drive

112a, 212a

Faltenhalterstator

112b, 212b

Blank holder runner

116, 216

first stamp actuator element / winding

117, 217

second punch actuator element / permanent magnet

118, 218

first fold holder actuator element / winding

119, 219

second fold holder actuator element / permanent magnet

124, 224

Blank holder guide cylinder

126, 226

Punch guide cylinder

130, 230

Stamp symmetry axis

132, 232

Blank holder symmetry axis

304

air duct

306

Air outlet opening

310

stamp ram

316

Verdichteraktorelement

410

Matrizenstößel

416

Auswerferaktorelement

505

molding

513

Blank holder segment drive

524

Blank holder segment

Claims (15)

Device for compression drawing of flat fiber material, comprising a punch (121, 221, 521) designed to cooperate with a drawing die (122, 222, 522) in a forming process, and a fold holder (123, 223, 523), the punch ( 121, 221, 521) is longitudinally movably guided with one degree of freedom for movement in or parallel to a punch symmetry axis (130, 230, 530), said fold holder (123, 223, 523) having a pleat holder guide cylinder (124, 224) adapted to Cooperating with a pleat holder guide bushing (104, 204) such that the pleat holder (123, 223, 523) is longitudinally movably guided with one degree of freedom for movement in or parallel to a pleat holder axis of symmetry (132, 232, 532) to a frame (108, 208, 508) and at least the fold holder guide bushing (104, 204) immovably connected to the frame (108, 208, 508), wherein the fold holder guide sleeve (104, 204) is integrally connected to at least one first fold holder actuator element (118, 218) and forms therewith a fold holder stator (112a, 212a), said fold holder guide cylinder (124, 224) having at least one second fold holder actuator element (119, 219). is integrally formed and with this together a Faltenhalterlaufer (112b, 212b) is formed, wherein the Faltenhalterstator (112a, 212a) and the Faltenhalterläufer (112b, 212b) for interaction as a Faltenhalterantrieb (112, 212, 512) are provided, wherein the punch symmetry axis ( 130, 230, 530) and the folding axis of symmetry axis (132, 232, 532) have the same position, said punch (121, 221, 521) having a punch guide cylinder (126, 226) adapted to cooperate with a punch guide bushing (106, 206) in that the punch (121, 221, 521) is longitudinally movable with one degree of freedom for movement parallel to the punch axis (130, 230, 530) t and is driven, wherein the punch guide bushing (106, 206) is integrally connected to a first stamp actuator element (116, 216) and forms together with this a stamp stator (110a, 210a), the stamp guide cylinder (126, 226) having a second stamp actuator element (117, 217) is integrally connected and forms together with this a punch rotor (110b, 210b), wherein the stamp stator (110a, 210a) and the punch rotor (110b, 210b) for cooperation as a punch drive (110, 210, 510) are provided wherein the Faltenhalterstator (112a, 212a), the Faltenhalterläufer (112b, 212b), the Stempelstator (110a, 210a) and the punch rotor (110b, 210b) have the same position, either in a first embodiment, the Faltenhalterstator (112a) immobile with the frame (108) connected, the stamp stator (110a) is integrally connected to the Faltenhalterführungszylinder (124) and the Faltenhalterführungszylinder (124) at the same time forms the punch guide bush (106) in which the punch rotor (110b) is mounted longitudinally movable or according to a second embodiment, the stamp stator (210a ) and the Faltenhalterstator (212a) immovably to the frame (208, 508) are connected. The apparatus of claim 1, wherein the stamper stator (210a) and the Faltenhalterstator (212a) are arranged one behind the other in the axial direction or wherein the Stempelstator (210a) and the Faltenhalterstator (212a) are arranged in the same plane and the coupling of the Stempelstators (210a) the frame (208, 508) via the Faltenhalterführungsbuchse (204) by at least one coupling element between the stamp stator (210a) and Faltenhalterführungsbuchse (204) is passed through at least one recess in the Faltenhalterläufer (212b), wherein the recess in the axial direction at least as long is designed that an unobstructed stroke of the pleat holder (223, 523) is made possible. Device according to one of claims 1 or 2, wherein the punch (121, 221, 521) during the entire course of movement or only on a first part of its course of movement and before immersion in the drawing die (122, 222, 522) in the punch guide bushing (106 , 206). Device according to one of the preceding claims, wherein the punch drive (110, 210, 510) and / or the fold holder drive (112, 212, 512) are designed as an electric linear drive. Apparatus according to claim 4, wherein the first Faltenhalteraktorelement (118, 218) as at least one winding and the second Faltenhalteraktorelement (119, 219) is designed as at least one permanent magnet or vice versa. Apparatus according to claim 4 or 5, wherein the electric linear drive in the narrow space between the fold holder guide bushing (204) and fold holder guide cylinder (124) comprises high-energy rare earth magnets. Apparatus according to claim 6, wherein sintered neodynium-iron-boron magnets having the highest possible energy density or higher-temperature sintered samarium-cobalt magnets are provided as high-energy rare-earth magnets. Apparatus according to any of claims 4 to 7, wherein the guide is disposed between the pleat-holder guide cylinder (124, 224) and the pleat-holder guide bush (104, 204). and / or between the punch guide cylinder (126, 226) and the punch guide bushing (106, 206) are designed as rolling guides or as aerostatic guides or as spring guides. Device according to claim 8, wherein a rolling guide integrated directly into the magnetic circuit of the stamp stator (110a, 210a) and punch runner (110b, 210b) and / or the magnetic circuit of fold holder stator (112a, 212a) and fold holder runner (112b, 212b) is provided. Device according to one of claims 4 to 9, wherein the electric linear drive comprises a drive device which allows a position-controlling or position-controllable, force-regulating or force-controllable or force-controlling or force-controllable control. Device according to one of claims 1 to 10, wherein the fold holder (123, 223, 523) is designed as a segmented fold holder comprising Faltenhaltersegmente (524), which on the blank of a molding (505) facing surface fold holder (523) arranged and are provided for contact with the blank, wherein the the fold holder (123, 223, 523) is further designed in such a way that it segmentally, spatially resolved force adjustable or force controllable, over the course of the compression drawing variable, time-resolved Faltenhalterkräfte exerts, including the segmented Wrinkle holder several, at least in groups independently controllable Faltenhalterantriebe (112, 212), the Faltenhaltersegmentantriebe (523) form. Device according to one of claims 1 to 11, wherein the punch drive (110, 210, 510) is controllable in such a way that a vibration superimposed compression pulling is executable. Device according to one of claims 1 to 12, wherein a demolding device is provided as a cutting device combined with a scraper edge and the punch drive (110, 210, 510) can be controlled in a work performing forward movement and a backward work verrichtenden working. Device according to one of claims 1 to 13, wherein the demolding device for exerting media pressure or vacuum on the molding or as an ejector from the drawing die (122, 222) is executed. Apparatus according to claim 14, wherein the media pressure is caused by a plunger (310) which is longitudinally drivable in an air passage (304) inside the punch (121, 221, 521), and from an air outlet opening (306) at a bottom of the Stamp (121, 221, 521) can be discharged; wherein the vacuum is caused by a die tappet (410) which is longitudinally movably drivable in the draw die (122, 222, 522); and / or wherein the die tappet (410) is controllable as an ejector.

Images