EP4426542A2 - Heating element of a packaging machine - Google Patents

Abstract

The present invention relates to a heating element for heating the packaging material, in particular a plastic monofilm, in a packaging machine. The present invention further relates to the packaging machine itself and to a method for heating a material web or for producing a packaging tray.

Description

Heating element of a packaging machine

The present invention relates to a heating element for heating or warming the packaging material, in particular a monoplastic film, in a packaging machine. Furthermore, the present invention relates to the packaging machine itself and a method for heating a material web or for producing a packaging tray.

Heating elements are known from the prior art and are part of a packaging machine. With these packaging machines, a trough is formed by deep-drawing in a flat web of material, for example a web of film. To do this, the material web must be heated with a heating element before deep-drawing. Particularly in the case of monofoils, which consist of a single material, the heating must take place quickly and evenly, a minimum permissible temperature for the desired shape result must not be fallen below and a maximum permissible temperature must not be exceeded, with the difference between the minimum and maximum permissible temperature being very large is small, i.e. there is only a small temperature window. At the same time, the warm-up must take place quickly in order to be able to provide sufficient cycle power. Conventional heating elements do not or only insufficiently meet these requirements.

It was therefore the object of the present invention to provide a heating element and a packaging machine and a method for heating a material web or for producing a packaging tray which do not have the disadvantages of the prior art.

The object is achieved by a heating element for heating the packaging material, in particular a monoplastic film, in a packaging machine with a large number of segments that can be heated individually, the heating element having a longitudinal direction and a transverse direction, the heating element having at least three segments, of which at least one segment in the edge area of the heating element and at least one segment in the central area of the heating element are provided.

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa. This subject matter of the present invention relates to a heating element which is used for heating a material web, in particular in a packaging machine. Preferably, the web of material is stationary when heated and rests against the heating element. For this purpose, the heating element can have a means that improves the contact between the web of material and the heating element, which is provided in particular in such a way that the web of material bears against the heating element over its entire surface. Preferably the heating element is a plate, but not necessarily but preferably such a flat two-dimensional object. However, it can also be curved or have a different 3-dimensional shape. The heating element is preferably located upstream of the forming tool, in relation to the transport direction of the material web, for example as a so-called preheating. Alternatively or additionally, the heating element is integrated into the mold, for example as a so-called cover heater. The heating element can be connected directly to a carrier that is part of the packaging machine, in particular part of the forming station and here in particular part of the upper tool, or be an integral part of the carrier. This carrier can be provided to be vertically movable, so that it can be moved towards and away from the material web. Thermal insulation is preferably provided between the heating element and the carrier. Furthermore, protection is preferably provided between the heating element and the thermal insulation, preferably directly on the heating element, for example a protective plate only a few tenths of a millimeter thick, in order to preferably protect a heating element provided as a heating foil from mechanical damage on its underside, for example as a result of contact, in particular in the sense of a permanent pulsating load, with edges or drill hole edges of the thermal insulation and/or a carrier plate. Such contact can otherwise lead to at least partial or local damage to the heating element.

The heating element, which is preferably operated with electrical energy, heats the material web preferably from one side, for example from above as in a cover heater or from below as in a so-called "preheating from below", or from both sides, for example from above and below. as in a sandwich heating as so-called "preheating from above and below", especially if the energy input into the material web should be even faster.

Each heating element has at least one heating means with which the segments according to the invention are realized. Segments are areas/heating zones of the heating element, in particular areas facing the material web, which have a different actual temperature and/or a different target temperature are regulated / controlled and / or in which different amounts of heat energy and / or heat energy performance are transferred to the material web.

For this purpose, the heating element can have several, in particular discrete, heating means, for example 5-50, preferably 51-100, even more preferably 101->1000 heating means.

Such heating means are, for example, one or more printed circuit boards, which can each be supplied with electrical energy differently in order to achieve different actual temperatures in the segments and/or be regulated/controlled with different actual and/or setpoint values. The heating means can be provided according to a specific pattern. They are preferably not provided equidistantly. The heating means of a heating element can differ from one another in terms of shape and/or size and/or heating capacity. The heating means can also consist of a large number of pixels which can be controlled individually and/or in groups. These pixels can be arranged in a specific pattern in a segment and/or in the heating element. The pixels are preferably distributed equidistantly across the heating element. A specific number of pixels are preferably arranged on a printed circuit board, it being possible for the heating element to have a large number of such printed circuit boards. The pixels of a circuit board can be controlled individually or in one or more groups.

The heating means is preferably provided as a heating foil or as a printed circuit board.

On the side of the heating element facing the web of material to be heated, this preferably has a cover element, preferably made of a material with good thermal conductivity, in particular metal, preferably aluminum or stainless steel. There is preferably a direct and preferably full-surface contact between the heating means and the covering element. The person skilled in the art understands that “full-area contact” also means that, for example, the covering element is preferably glued to the heating means(s) over the whole area, with the adhesive, which is provided for example as double-sided adhesive tape, preferably conducting heat well. The protection/protective plate is also preferably glued. The heating element thus preferably consists of a heating means and a covering element and preferably a protection. The cover element is preferably essentially plate-shaped and very particularly preferably has an angled, preferably essentially completely circumferential edge area.

Alternatively or additionally, a cover element can be provided as a film or coating, which preferably has a non-stick effect on the web of material to be heated in order in particular to promote slight local migration of the material web on the heating element to compensate for/smooth out creases or to prevent or minimize a disruptive adhesion of the finished heated material web during detachment from the heating element, which can be helpful, for example, with material webs that mainly consist of A-PET and/or A-PET recyclate in order to prevent or minimize, for example, undesired deformations or creases on the material web and wear on the heating element or the cover element.

The heating element has a longitudinal direction and a transverse direction. These can be the same as in a square or different as in a rectangle.

According to the invention, the heating element has at least three segments, of which at least one segment is provided in the edge area, i.e. in the area of the outer circumference of the heating element, and at least one segment is provided in the central area of the heating element. A segment within the meaning of the present invention is an area of the heating element: in which one, in particular a single, preferably individually adjustable, actual temperature is set and/or which is regulated/controlled with a, in particular a single, in particular individually selectable target temperature and /or in which a specific, in particular individually selectable amount of thermal energy and/or a specific, in particular individually selectable, thermal energy output is transferred to the material web.

Two segments of the heating element can differ in that they have a different actual temperature and/or that they are regulated/controlled with a different setpoint temperature and/or that different amounts of heat energy and/or heat energy outputs are transferred to the material web.

The segments are preferably selected or operated in terms of shape and/or size and/or setting values in such a way that a packaging material, in particular a monofoil, is heated up as evenly as possible and/or as quickly as possible.

The respective segment can be made available in the form of one or more electrical conductor tracks. However, a segment can also have a large number of heating means, for example pixels, which can be controlled individually or in groups. The segments of a heating element can be provided as separate components or on a common carrier. The central area of the heating element preferably refers to the area of the geometric center of the surface of the heating element which faces the web of material. The segment(s) in the edge area preferably border the heating element(s) in the central area. The segments are preferably each provided essentially square or rectangular. A gap may be provided between the segments. The shape and/or size of the segment preferably does not correspond to the shape and/or size of the packaging trays that are to be deep-drawn after heating.

Two segments of the edge area can extend over the entire length of the heating element or over the entire width of the heating element. The other segments of the edge area are then preferably correspondingly shorter.

According to a preferred embodiment, the heating element has one to eight segment(s) in the edge area and at least one segment, preferably two or three, even more preferably four segments in the central area of the heating element.

Preferably, the heating element has four segments, wherein: three segments are provided in the peripheral area and one segment in the central area, or two segments are provided in the peripheral area and two segments are provided in the central area, or one segment is provided in the peripheral area and three segments are provided in the central area.

Furthermore, a heating element preferably has five segments, with four segments being provided in the edge area and one segment in the central area, or three segments being provided in the edge area and two segments being provided in the central area, or two segments being provided in the edge area and three segments being provided in the central area or one segment in the edge area and four segments in the central area are provided.

Another preferred embodiment is a heating element that has six segments, wherein: at least three segments in the edge area and at most three segments in the

Central area are provided, or three segments are provided in the edge area and three segments are provided in the central area, or at most two segments are provided in the edge area and at least four segments are provided in the central area.

Still another preferred object of the present invention is a heating element having seven segments, wherein: at least three segments in the peripheral area and at most four segments in the

Central area are provided, or three segments are provided in the edge area and four segments in the central area, or four segments are provided in the edge area and three segments are provided in the central area, or a maximum of six segments are provided in the edge area and at least one segment in the central area.

Also preferred is a heating element that has eight segments, wherein: at least four segments are provided in the edge area and at most four segments in the central area, or five segments are provided in the edge area and three segments are provided in the central area, or four segments are provided in the edge area and four segments in the central area Central area are provided or a maximum of six segments in the edge area and at least two segments in the central area are provided.

The person skilled in the art understands that heating elements with more than eight segments are also provided, for example 11 segments or even many more, the combinations of which in the edge and central area are preferably designed analogously to the combinations described above.

According to a preferred embodiment of the present invention, the heating element has eight heating segments in the edge area and at least two segments, preferably three heating segments, in the central area of the heating element. Preferably, the longitudinal extension of two segments of the edge area runs parallel to the Longitudinal direction of the heating element and two segments of the edge region parallel to the transverse direction of the heating element. The other four segments of the edge area are preferably corner segments.

More than one segment in the central area has the particular advantage that the electrical power required to heat up the material web can be made available more easily. In particular, the cross section of the electrical lines can be reduced and the safety technology can be simplified. The at least two segments make it possible to heat the material web quickly and evenly. A small temperature window in which the material web is to be heated can be safely maintained.

The heating element preferably has a low mass and/or a low thermal capacity, which means that, for example, unwanted overheating or overshooting beyond the desired temperature window (set point temperature window) can be avoided.

According to a preferred embodiment of the present invention, corner segments for heating the material web are provided in the edge area, which can be controlled separately from the other segments of the edge and/or central area. This enables the material web to be heated particularly evenly.

The segment(s) in the edge area preferably encloses the at least one segment in the central area, at least essentially over the entire circumference, preferably over the entire circumference. The segment(s) is/are preferably provided as a ring, it being possible for this ring to be provided from a number of segments and/or to be interrupted by a gap(s).

For example, a U-shaped segment is provided in the edge area and another segment is preferably provided at or between the two ends of the open legs of the U-shaped segment, so that a closed edge ring segment is formed when the two segments are combined.

Preferably each segment has a plurality of heating means. For example, the segment has several, in particular discrete, heating means, for example 5-50, preferably 51-100, even more preferably 101->1000 heating means, which can be controlled individually or in groups. Such heating means are for example, one or more electronic components and/or conductor tracks, which are preferably provided on a printed circuit board and which can each be supplied with electrical energy differently in order to achieve different temperature ranges in the respective segment and/or with different actual and/or setpoint values to be regulated/controlled. The heating means can be distributed on the segment according to a certain pattern. They are preferably not provided equidistantly. For example, more heat output is made available in the edge area of a segment than in its central area. The heating means of a segment can differ from one another in terms of shape and/or size and/or heating capacity. The heating means can also consist of one or a large number of pixels that can be controlled individually and/or in groups. These pixels can be arranged in a certain pattern in the respective segment. They are preferably provided equidistantly. For example, more heating power is made available in the edge area of a segment than in its central area. The pixels are preferably distributed equidistantly over the segment. A specific number of pixels are preferably arranged on a printed circuit board, with the segment being able to have one or a multiplicity of such printed circuit boards. The pixels of a circuit board can be controlled individually or in one or more groups.

The heating element preferably has a controller/regulator with which a setpoint temperature and/or an energy input value for the respective segment or segments can be specified and regulated/controlled. This control/regulation can be part of the control/regulation of the packaging machine or a separate unit.

The control/regulation preferably controls/regulates the segments in such a way that their actual temperature and/or their energy input before and/or during heating is different, for example the energy input can be erratic from the moment of contact between the segments and the film to be heated increase.

Each segment preferably has a sensor with which the actual temperature and/or the energy input can be measured, for example using the ohmic resistance of the heating element or using a separate sensor. This measurement is preferably carried out discontinuously, alternatively continuously.

The control/regulation preferably controls/regulates the segment(s) in the edge region of the heating means and/or in the segment itself with a higher target temperature and/or a higher energy input than the segment and/or for the segments in the central area and/or the central area of the segment itself.

If two or more segments of the heating element are provided, they are preferably operated with a different target temperature and/or a different energy input. The downstream segment, based on the running direction of the material web, is preferably operated with a higher target temperature and/or a higher energy input.

The target temperature and/or the energy input values for the segments in the edge area of the heating element, which run parallel to the transport direction of the material web, are preferably the same.

Preferably, the control/regulation for a segment of the edge region parallel to the direction of transverse extent provides a higher target temperature and/or a higher energy input than for the opposite segment of the edge region in the direction of transverse extent and/or for at least one, preferably all, segment(s) in the central region. For example, a higher energy input can be required for such a segment because it experiences an additional energy loss through adjacent tool components.

The at least two, preferably three or more, segments in the central area of the heating element preferably have a different target temperature and/or a different energy input, at least in part.

The setpoint temperature and/or the energy input value for the segments in the edge region of the heating element is preferably the same parallel to the direction of longitudinal extension.

The heating element preferably has corner heating segments in the edge area.

According to a further preferred embodiment of the present invention, the control/regulation controls/regulates the segments in the corner area of the heating element in such a way that a higher target temperature and/or a higher energy input is realized than with at least one, preferably several, in particular all segments of the edge area and/or or the segment(s) in the central area of the heating element, in particular for the segment(s) in the edge area in the direction of transverse extension and/or the segments in the central area and/or the segment(s) in the edge area in the longitudinal direction.

Preferably, the setpoint temperature changes for at least one, preferably all, segments during a heating cycle, i.e., for example, one cycle of a packaging machine that operates in cycles.

According to another inventive or preferred subject matter of the present invention, the heating element, in particular its regulation/control, has an electronic booster with which an increased energy input into the respective heating element occurs for a short time independently of the target temperature.

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa.

Such a booster can, for example, be a capacitor that discharges, for example, as soon as the temperature of the heating element or a segment drops sharply or as soon as the signal “advance the material web” comes from the packaging machine. The energy released in the process is then converted into thermal energy in order to reduce, preferably stop, the drop in temperature of at least one segment. The capacitor can be charged once the booster function is no longer needed. Alternatively, the regulation/control provides the necessary energy for the booster directly from the available power grid.

The web of material is preferably a monoplastic film or monofoil, i.e. a plastic film which consists of at least one layer and/or a single material or predominantly consists of a single material, for example at least 95% by weight of one material and/or a mixture of substances consists of a group of materials and is preferably considered to be recyclable and/or moderately or highly recyclable; in contrast to multi-layer foils or foils that consist of a mixture of substances from different material groups that are considered to be non-recyclable or at most slightly recyclable. The material of the monofilm is preferably 100% by weight or the majority, in particular at least 95% by weight, polypropylene (PP), polyethylene (PE) or polyethylene terephthalate (PET) or a mixture of substances from just one material group, for example polyolefins , such as PP and PE. For example, a monofilm can consist of at least 95% by weight of at least one PP layer, which is connected to a sealing or peeling layer made of PE.

The thickness of the monofilm is preferably 250-500 μm, particularly preferably 290-310 μm. The temperature of the temperature window is preferably 135-137° C. or the temperature window covers a range of preferably 3 Kelvin.

With a thickness of the monofoil of 250-500 μm, 2.5-5 seconds are preferably required, or even only 1-3 seconds with greater energy input, in order to bring the material web to the desired temperature, at which thermoforming with a thermoforming result, i.e for example good shape is possible.

According to a further inventive or preferred subject matter of the present invention, the energy transfer per unit of time from the heating element to the material web is not constant over time during the heating. Preferably, at least 40%, preferably at least 50%, even more preferably at least 60% of the heating energy required to reach the desired temperature of the material web is transferred to the material web within 30% of the heating time.

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa.

Furthermore, preferably or according to the invention, the target temperature changes for at least one, preferably several, in particular all segments during a heating cycle.

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa.

Preferably, the target temperature of at least one, preferably several, in particular all of the segments of the heating element before contact with the material web is higher than the permissible maximum temperature of the material web to be heated, in particular the monofoil. This setpoint temperature is then preferably lowered in the course of the heating process, in particular to a value of the maximum permissible maximum temperature of the material web to be heated. Alternatively or additionally, the heating system can be operated with a low-voltage network, for example 400V, or in particular a low-voltage network, for example less than 50V, in order to be able to provide very high amounts of electrical energy for a short time, which is then converted into heating energy.

The material web can be heated up quickly thanks to the increased set temperature and/or the booster function. This has proven to be the quality of the resulting deep-drawn packaging tray in terms of shape, for example in terms of pronounced contours, shape and dimensional accuracy compared to the shape of the tool, thickness distribution, for example within a package and/or an entire preference, transparency and/or color turned out to be advantageous.

The object is also achieved with a packaging machine with a forming station, a filling station, a sealing station and a longitudinal and/or cross cutter, wherein a material web can be transported along a running direction, in particular cyclically, and which has an inventive or preferred heating element according to the present invention .

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa.

This subject matter of the present invention relates to a packaging machine for producing packaging in which a base material web, for example a plastic film or a material web, which in particular has a cardboard, paper or other layer different from plastic, is unwound from a supply roll and preferably intermittently/cyclically is transported along the packaging machine in a transport plane. In a forming station, this web of lower film is then initially shaped by means of a deep-drawing tool in order to form, for example, a trough and/or a structure, in particular an anti-slip structure, in the web of lower material. As a rule, the forming station has a lower and an upper tool, which are moved towards one another for forming and away from one another for further transport of the lower web of material. The lower tool is located below and the upper tool above the transport level of the lower web of material. In general, in the packaging machine according to the invention, several packages in one so-called format are arranged, processed simultaneously and then simultaneously transported along the packaging machine. Before and/or during deep-drawing, the web of base material is heated with a heating element. The lower web of material is then covered with packaged goods, in particular foodstuffs such as sausage, ham or cheese, alternatively, for example, non-food packaged goods such as medical technology or other products, and in a next step sealed with a top film in a sealing station, with the Upper film is usually sealed to the lower film web. Another heating element is used for this purpose, which provides the thermal energy required for sealing. The packaging thus finished is then separated by cutting out the packaging from the lower and upper web of material, for example using a cross cutter and a longitudinal cutter. The cross or longitudinal cutter can also be made available as a contour punch. The web of upper material is also unrolled from a supply roll and can also be thermoformed, for example in an upper film forming station, after it has preferably been heated with the heating element according to the invention. In relation to the transport direction of the respective film web, a dancer is preferably located downstream of at least one supply roll, which dancer keeps the tension in the respective material web at least substantially constant. The dancer can be, for example, a linear or a rotary dancer.

The heating element, which heats the web of material to be thermoformed, is preferably located upstream of the forming tool(s) of the forming station. The heating element can be firmly connected to one tool, for example the upper tool, and/or its frame and can, for example, be moved vertically together with it.

The distance between the mold and the upstream heating element is preferably as small as possible, preferably a few millimeters, preferably 0.5 to 1 mm, on the one hand to save space and material web, on the other hand to reduce or even to cool down the material web before molding minimize, but in particular to be able to heat the material web in the format area directly upstream. Preferably, a segment whose longitudinal extent is parallel to the transverse extent of the heating element is provided immediately adjacent to the forming station.

Preferably, based on the running direction of the material web, the heating element is provided upstream of the forming station and/or the longitudinal direction of the heating element extends parallel to the running direction of the material web. The deep-drawn material web is preferably cooled in the forming station. It is particularly preferable for the shape (die) to be cooled, particularly preferably for rapid cooling.

The object is also achieved with a method for heating a material web, in which the material web is brought into contact with a heating element for heating, with an energy boost being introduced into the material web when the material web comes into contact with the heating element.

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa.

This subject matter of the present invention relates to a method for heating a material web, for example in a packaging machine, in particular in a so-called “form-fill-seal” packaging machine.

The web of material is preferably a plastic film, in particular a so-called monofilm, which is disclosed in detail above.

The method according to the invention ensures that the material web is heated quickly and uniformly within a narrow temperature window.

The material web is preferably heated by means of the heating element by radiation and/or heat conduction.

According to the invention, the energy input for heating the material web takes place by means of an energy boost, which begins in particular as soon as the material web touches the heating element. With an energy boost within the meaning of the invention, at least 40%, preferably at least 50%, even more preferably at least 60% of the heating energy is transferred to the material web within 30% of the heating time.

The amount of energy required for this can be made available by an increased amount of energy that is stored in the heating element and/or by an electronic booster. The booster preferably acts in two time periods and preferably differently therein. The booster in the first time segment is preferably started together with or when the signal “preferential start” is present and preferably ends when the lower and upper tools are closed after they have previously been moved towards one another. The second period of time preferably starts at the moment when the material web touches the heating element, which preferably ends at the end of the heating of the material web, when ventilation starts and the material web detaches from the heating element, just before the lower and upper tools open.

During the first period of time, the booster increases the temperature of the heating element, for example 100°C to 135-137°C, which corresponds to the critical film temperature of PP film, or particularly preferably even to 138° or 139°C with some excess heat. The excess heat above the critical film temperature is implemented in order to be able to transfer as much energy as possible into the film without overheating the film. The first time segment lasts only about 1-1.5 seconds, for example.

During the second period of time, the booster compensates for the heat dissipation through the material web, which is usually only exposed to ambient temperature before contact, which quickly draws energy from the heated heating element, so that energy must also be quickly fed into the heating element so that the target temperature in the material web of e.g 135-137°C is reached safely and quickly. The duration of the second period of time depends in particular on the thickness of the material web, with a duration of approx. 1 second per 100 μm thickness of the material web being used as a guide value, ie a duration of approx. 4 seconds is required for a thickness of 400 μm.

Furthermore, according to the invention or preferably, a material web, in particular a monofoil, which has a maximum permissible heating temperature is heated in the inventive or preferred method, wherein the temperature of the heating element can be at least temporarily higher than the permissible heating temperature of the material web. The temperature of the heating element is preferably increased above the maximum permissible temperature of the material web, particularly before the heating element and the material web touch, and is preferably lowered upon contact, preferably at least temporarily reduced below the maximum permissible temperature of the material web. Another object of the present invention is a method for producing a packaging trough, in which a web of material is heated using the method according to the invention and/or the preferred method and the trough is then formed.

The statements made on this subject matter of the present invention apply equally to the other subjects and vice versa. Features of this subject of the present invention may be incorporated into other subjects and vice versa.

The material web is preferably cooled during and/or after forming. The forming station preferably has cooled deep-drawing molds for this purpose; i.e. the matrix into which the material web is drawn and/or pressed is preferably cooled.

The invention is explained below with reference to FIGS. These explanations are merely exemplary and do not limit the general inventive concept.

FIG. 1 schematically shows the packaging machine according to the invention.

FIGS. 2-6 each show an embodiment of the heating element according to the invention, in particular the distribution of the segments over the surface of the heating element facing the web of material.

FIG. 1 shows the packaging machine 1 according to the invention, which has a forming station 2 , a filling station 7 and a sealing station 15 . The packaging machine can be a so-called thermoformer. A base material web 8, here a plastic film 8, in particular a monofilm made of PP, PE or PET, is pulled off a supply roll and transported in cycles from right to left along the packaging machine according to the invention. With each cycle, the sub-material web 8 is transported further by one format length/advance length. For this purpose, the packaging machine has two transport means 21 (see FIG. 5), in the present case two endless chains each, which are arranged to the right and left of the base web 8 . At least one gear wheel is provided for each chain both at the beginning and at the end of the packaging machine, around which the respective chain is deflected. At least one of these gears is driven. The gear wheels in the input area and/or in the output area can be connected to one another, preferably by a rigid shaft. Each transport means has a plurality of clamping means/grippers which grip the base material web 8 in the inlet area in a clamping manner and the movement of the transport means on the Sub-web 8 transferred. In the outlet area of the packaging machine, the clamping connection between the transport means and the base material web 8 is released again. A heating element is provided downstream of the inlet area and upstream of the forming station 2, which heats the base material web 8, in particular when the latter is at a standstill. The forming station 2 has a lower tool 4 and an upper tool 3 . As indicated by the double arrow, the lower tool 4 can be moved up and down, being moved upwards in the direction of the lower material web 8 for shaping and downwards for further transport of the lower material web 8 . In the raised position, the web of base material is preferably clamped between the two tools 3, 4. The lower tool 4 can be arranged on a lifting table 5, which, as symbolized by the double arrow, can be vertically adjustable in order to produce the movement of the lower tool described above. In the further course of the packaging machine, the packaging troughs 6 indicated here formed in the base material web or the base material web 8 are then filled with the packaged goods 16 in the filling station 7 . In the subsequent sealing station 15, which also consists of an upper tool 12 and a lower tool 11, which can be vertically adjusted if necessary, an upper film 14 is fixed to the lower web of material 8 by sealing in a materially bonded manner. As a result, the movement of the lower material web 8 is transferred to the upper material web 14 . In the sealing station, too, the upper tool and/or optionally the lower tool are lowered or raised before and after each film transport. The upper film 14 can also be guided in transport means or transported by transport chains, with these transport means then only extending in front of the sealing station and possibly upstream. Otherwise, the statements made regarding the means of transport for the lower film apply. The top film can also be heated and/or thermoformed with a heating element. For example, a sealing frame is provided as the lower tool 11 for sealing, which has an opening per packaging trough, into which the packaging trough, if present, dips during sealing, ie during the upward movement of the lower sealing tool. For sealing, the upper and lower webs of material are pressed together between the upper and lower tools 12, 11 and bond under the influence of heat and pressure. After sealing, the tools 11, 12 are moved apart again vertically. A dancer, for example a rotary dancer, can be provided between the supply roll of the upper material web 14 and the sealing tool, which keeps the material web 14 at a constant tension as far as possible. The person skilled in the art understands that a dancer is preferably also provided in the area of the base material web 8, preferably downstream of the supply roll. The dancer is preferably a linear dancer. Before and/or during the sealing of the upper web of material to the lower web of material takes place in each packaging cavity preferably a gas exchange. For this purpose, the air present in the packaging tray is first of all partially sucked off and/or replaced by an exchange gas. For this purpose, holes can be made in the base web 8 in the area of the transport chains in the area of each format, through which the air between the webs 8, 14 is sucked out and/or the exchange gas is blown in. In the further course of the packaging machine, the finished packages are separated, which is done with the cross cutter 18 and the longitudinal cutter 17, for example. In the present case, the cross cutter 18 can also be raised or lowered with a lifting device 9 . According to another embodiment, the sealing tool 11, 12 has a punch that cuts through the lower and upper material web before, during and/or after the sealing. Preferably, several packages are produced at the same time in each cycle, which are arranged in a so-called format as a matrix. The heating element 19 preferably has means with which the contact between the material web and the surface of the heating element can be established or improved. Such means are, for example, vacuum nozzles that suck the material web in the direction of the surface of the heating element.

Preferably, the heating element comprises a plate which can be provided on/on a support. The heating element provides the thermal energy with which the web of material is heated. A plate in the sense of the invention is not necessarily but preferably a flat two-dimensional object. It can also be curved or have a different 3-dimensional shape. The plate can be connected directly to the carrier. However, thermal insulation is preferably provided between the plate and the carrier, for example made of a very strong, heat-insulating material. Alternatively, the panel itself consists at least essentially of thermal insulation. According to the invention, the heating element has segments that make the heat output available. On the side of the heating element facing the web of material to be heated, the heating element preferably has a cover element, preferably made of a material with good thermal conductivity, in particular metal, preferably aluminum or stainless steel, which covers and thus protects the plate and/or the segments. The material web to be heated is preferably in full contact with the heating element, in particular the cover element or the segments. There is preferably a direct and preferably full-surface contact between the segments and the covering element. The heating element can therefore preferably consist of a plate, a carrier, several segments and a cover element, with additional heat insulation being provided on the back of the segments or the carrier and/or the plate being at least partially designed as heat insulation. Such heating elements are shown in Figures 2 - 6 shown schematically. The heating element 19 is provided upstream of the forming station in relation to the running direction 20 of the material web 8, the distance A between the forming station and the heating element preferably being as small as possible, preferably 0.5-1 mm. The tools in the forming station are preferably cooled. The heating element has a longitudinal extent L, which runs parallel to the direction of travel 20 and a transverse extent Q, which extends transversely to the direction of travel 20 . The heating element has a multiplicity of segments 21-28. Segments within the meaning of the invention are areas or zones of the heating element that have a different actual temperature and/or are regulated/controlled with a different target temperature and/or in which different amounts of heat energy and/or heat energy outputs are transferred to the material web. Each segment at least preferably has a plurality of heating means.

The heating element preferably has a control/regulation that controls the heating means of the segments. For example, a maximum permissible heating temperature of the material web can be specified for this control/regulation, which can be used, for example, as a target value for the control/regulation.

FIG. 2 shows a plan view of a first embodiment of the heating element according to the invention, which in the present case has six segments 21, 22, 23a, 24a, 25a, 26a. The segments 21, 22 are the segments in the central area of the heating element and the segments 23a - 26a are the heating surfaces in the edge area of the heating element, in each case based on its surface area parallel to the transport plane of the material web. It can be clearly seen that the length of the segments 23a, 24a, whose direction of longitudinal extent runs parallel to the transport direction of the material web, extends at least essentially over the entire length L of the heating element and that the length of the segments 25a, 26a, whose direction of longitudinal extent runs transversely runs to the transport direction of the material web, do not extend over the entire width Q of the heating element. The target temperatures of the segments and/or the energy supply are preferably set or controlled/regulated in such a way that:

T26 > T22 and/or T22 = T21 and/or T26 > T25, preferably T22 < T25 and/or T23 = T24 and/or T23 and/or T24 > T22 and/or T21

E26 > E22 and/or

E22 = E21 and/or

E26 > E25, preferably E22 < E25 and/or E23 = E24 and/or

E23 and/or E24 > E22 and/or E21

At least one, preferably a majority, in particular all of the conditions mentioned for this example should preferably be met.

With regard to Figure 3, reference can essentially be made to the statements according to Figure 2, whereby in this embodiment the length of the segments 23b, 24b, the longitudinal direction of which runs parallel to the transport direction of the material web, does not extend over the entire length L of the heating element and that the length of the segments 25a, 26a, the longitudinal direction of which runs transversely to the transport direction of the material web, extends at least essentially over the entire width Q of the heating element. The target temperatures of the segments and/or the energy supply are preferably set or controlled/regulated in such a way that:

T26 > T21 and/or T22, and/or

T26 > T23 and/or T22 = T21 and/or T26 > T25 and/or T25 > T21 and/or T22, and/or T23 = T24 and/or T23 and/or T24 > T21 and/or T22

E26 > E22 and/or E26 > E23 and/or E22 = E21 and/or E26 > E25 and/or E25 > E21 and/or E22, and/or E23 = E24 and/or E23 and/or E24 > E21 and/or or E22

At least one, preferably a majority, in particular all of the conditions mentioned for this example should preferably be met.

With regard to FIG. 4, reference can essentially be made to the statements according to FIGS. In the present case, the heating element 19 has corner segments 27, 27a to 27d, with which a particularly homogeneous heating of the material web 8 is possible. Furthermore, three segments 21, 22, 28 are preferably provided in the central area. The target temperatures of the segments and/or the energy supply are preferably set or controlled/regulated in such a way that:

T26C > T22a and/or

T26C > T23b and/or

T27a, b > T26, 26C and/or T22 = T2ia and/or T22a and/or T28 = T2ia and/or

T26C > T25b, preferably T22a > T25 and/or

T23b = T24b and/or

T27a = T27b and/or

T27C = T27d and/or

T27a > T27C and/or

T27b > T27d and/or

T27b > T27C and/or

T27a > T27d and/or

T23b and/or T24b > T22a and/or T2ia and/or T28

E26C > E22a and/or

E26C > E23b and/or

E27a, b > E26C and/or

E22a > E2ia and/or T22a and/or E28 > E2ia and/or

E26C > E25b, preferably E22a > E25b and/or

E23b = E24b and/or

E27a = E27b and/or

E27C = E27d and/or

E27a > E27C and/or

E23b and/or E24b > E22a and/or E2ia and/or E28

At least one, preferably a majority, in particular all of the conditions mentioned for this example should preferably be fulfilled.

With regard to FIG. 5, reference can essentially be made to the statements according to FIGS. In the present case, the heating element 19 has three segments 21b, 29 and 26d, of which a segment 21b is provided in the central area of the heating element and two segments in the edge area, of which two segments in the edge area are a U-shaped segment 29 and a segment 26d between the two ends of the open legs of the U-shaped segment 29 are provided. The target temperatures of the heating elements and/or the energy supply are preferably set or controlled/regulated in such a way that:

T29 > T2ib and/or T26d > T2ib and/or T26d > T29

E29 > E2ib and/or E26d > E2ib and/or E26d > E29

At least one, preferably a majority, in particular all of the conditions mentioned for this example should preferably be fulfilled. With regard to FIG. 6, reference can essentially be made to the statements according to FIGS. In the present case, the heating element 19 has two segments 21c and 30, of which a segment 21c is provided in the central area of the heating element and a segment 30 is provided in the edge area, which at least essentially completely encloses the one segment 21c in the central area. The target temperatures of the heating elements and/or the energy supply are preferably set or controlled/regulated in such a way that:

T30 > T21C

E30 > E21C

At least one, preferably a majority, in particular all of the conditions mentioned for this example should preferably be met.

Reference list:

1 packaging machine

2 forming station, deep-drawing station

3 Upper tool of the deep-drawing station

4 Lower tool of the deep-drawing station

5 lifting table, carrier of a tool of the sealing, deep-drawing station and / or

cutting device

6 packaging tray

7 filling station, insertion station

8 material web, sub-material web

9 lifting device, lift

10 Central area of the heating element

11 Lower tool of the sealing station

12 Sealing station upper die

13 Lower part of the material web clamping means

14 face material web, lid material web

15 sealing station

16 packaged goods

17 longitudinal cutters

18 cross cutters

19 heating element

20 running direction

21 - 21c segment in the central area

22 segment in the central area

23, 23a, 23b segment, edge area in the direction of longitudinal extension

24, 24a, 24b segment, edge area in the direction of longitudinal extension

25, 25a, 25b segment, entry area

26 - 26d segment, area adjacent to the deep drawing or heating segment in the outlet area

27 - 27d segment, corner zone

28 segment in the central area

29 segment, U-shaped segment

30 segment, segment in the edge area that is a heating surface element

Central area encased, frame-shaped rectangular segment

A Clearance between the forming station and the heating element L Longitudinal extension of the heating element

Q Transverse extension of the heating element

Tx Target temperature of heating segment x

Ex power supply of the heating element x

Claims

Patent Claims: 1. Heating element (19) for heating the packaging material, in particular a monoplastic film, in a packaging machine with a large number of segments (21 - 30) which can be heated individually, the heating element having a longitudinal direction (L) and a transverse direction (Q), characterized in that the heating element has at least three segments (21 - 30), of which at least one segment (23 - 27d, 29, 30) is in the edge area of the heating element and at least one segment (21 - 22, 28) in the central area (10 ) of the heating element are provided. 2. Heating element (19) according to claim 1, characterized in that it has one to eight segment(s) in the edge area and at least one segment, preferably two or three, even more preferably four segments in the central area of the heating element. 3. Heating element (19) according to one of claims 1 or 2, characterized in that it has four segments (21 - 30), with: three segments (23 - 27d, 29, 30) in the edge area and one segment (21 - 22 , 28) are provided in the central area or two segments (23-27d, 29, 30) are provided in the edge area and two segments (21-22, 28) are provided in the central area or one segment (23-27d, 29 , 30) in the edge area and three segments (21-22, 28) in the central area are provided. 4. Heating element (19) according to one of claims 1 or 2, characterized in that it has five segments (21 - 30), with: four segments (23 - 27d, 29, 30) in the edge area and one segment (21 - 22 , 28) are provided in the central area or three segments (23-27d, 29, 30) are provided in the edge area and two segments (21-22, 28) are provided in the central area or two segments (23-27d, 29 , 30) in the peripheral area and three segments (21-22, 28) in the central area, or one segment (23-27d, 29, 30) in the peripheral area and four segments (21-22, 28) in the central area I are provided. Heating element (19) according to one of Claims 1 or 2, characterized in that it has six segments (21 - 30), with: at least three segments (23 - 27d, 29, 30) in the edge area and at most three segments (21 - 22 , 28) are provided in the central area or three segments (23 - 27d, 29, 30) in the edge area and three segments (21 - 22, 28) in the central area are provided or at most two segments (23 - 27d, 29, 30) in the edge area and at least four segments (21 - 22, 28) are provided in the central area. Heating element (19) according to one of Claims 1 or 2, characterized in that it has seven segments (21 - 30), with: at least three segments (23 - 27d, 29, 30) in the edge area and at most four segments (21 - 22 , 28) are provided in the central area or three segments (23 - 27d, 29, 30) in the edge area and four segments (21 - 22, 28) are provided in the central area or four segments (23 - 27d, 29, 30) in the edge area and three segments (21 - 22, 28) are provided in the central area or at most six segments (23-27d, 29, 30) are provided in the edge area and at least one segment (21-22, 28) are provided in the central area. Heating element (19) according to one of Claims 1 or 2, characterized in that it has eight segments (21 - 30), with: at least four segments (23 - 27d, 29, 30) in the edge area and at most four segments (21 - 22 , 28) are provided in the central area or five segments (23 - 27d, 29, 30) in the edge area and three segments (21 - 22, 28) are provided in the central area or four segments (23 - 27d, 29, 30) in the edge area and four segments (21 - 22, 28) are provided in the central area or at most six segments (23-27d, 29, 30) are provided in the edge area and at least two segments (21-22, 28) are provided in the central area. Heating element (19) according to one of the preceding claims, characterized in that it has corner segments (27) in the edge region. Heating element (19) according to any one of the preceding claims, characterized in that the segment (30) in the edge region at least one Segment (21c) in the central area, at least substantially over the entire circumference, preferably over the entire circumference. Heating element (19) according to one of the preceding claims, characterized in that it has a U-shaped segment (29) in the edge area and a further segment (26) at or between the two ends of the open legs of the U-shaped segment (29) is provided. Heating element (19) according to any one of the preceding claims, characterized in that each segment has a plurality of heating means. Heating element (19) according to claim 11, characterized in that the heating elements are not distributed equidistantly. Heating element (19) according to one of the preceding claims, characterized in that it has a control/regulation with which a target temperature and/or an energy input value for the segments (21 - 28) can be specified. Heating element (19) according to Claim 13, characterized in that the control/regulation for the segment (26) provides a higher target temperature and/or a higher energy input than for the segment (25) and/or for the segments (21, 22, 28) in the central area. Heating element (19) according to claim 13 or 14, characterized in that the segments (21, 22, 28) in the central area of the heating element have a different setpoint temperature and/or a different energy input. Heating element (19) according to one of Claims 13 - 15, characterized in that the desired temperature and/or the energy input values for the segments (23, 24) in the edge area of the heating element are the same. Heating element (19) according to any one of claims 13 - 16, characterized in that the control / regulation for the segments (27) in the corner area of the heating element provides a higher setpoint temperature and / or a higher energy input than for the segment (25, 26) and/or the segments (21, 22, 28) and/or the segment (23, 24). Heating element according to one of Claims 13 - 17, characterized in that the setpoint temperature changes for at least one, preferably all, segments during a heating cycle. Heating element, in particular according to one of the preceding claims, characterized in that it has an electronic booster, with which an increased energy input into the respective heating element occurs for a short time independently of the target temperature. Packaging machine (1) with a forming station (2), a filling station (7), a sealing station and a longitudinal and/or cross cutter (17, 18), a material web (8) being transportable along a running direction (20), in particular cyclically is characterized in that it comprises a heating element according to any one of the preceding claims. Packaging machine (1), characterized in that, in relation to the running direction (20) of the material web, the heating element (19) is provided upstream of the forming station (2) and/or in the forming station (2) and/or the direction of longitudinal extent (L ) extends parallel to the running direction (20). Packaging machine (1) according to one of Claims 20 or 21, characterized in that the forming station has cooled deep-drawn troughs. Packaging machine (1) according to any one of Claims 20 - 22, characterized in that the segment (26) is provided immediately adjacent to the forming station. Method for heating a web of material, wherein the web of material is brought into contact with a heating element for heating, characterized in that when the web of material comes into contact with the heating element, an energy boost is introduced into the web of material. Method according to claim 24 or according to the preamble of patent claim 24, wherein a material web, in particular a monofoil, with a maximum permissible Heating temperature is processed, characterized in that the temperature of the heating element is at least temporarily higher than the permissible heating temperature of the material web. Method for producing a packaging trough (6), characterized in that a web of material is heated using the method according to claims 24 and 25 and the trough is then formed. Method according to Claim 26, characterized in that the material web is cooled during moulding.