MATERIAL

The invention concerns the process and apparatus for manufacturing a crimped sheet, preferably used in the production of an aerosol-generating article.

Typically, aerosol-generating articles comprise a plurality of elements assembled in the form of a rod. The plurality of elements generally includes an aerosol-forming substrate and a filter element. One or both of the filter element and the aerosol-forming substrate may comprise a plurality of axial channels to provide air-flow in the axial direction. The plurality of axial channels may be defined by a sheet that has been crimped and gathered within the rod to form the channels. In such examples, the crimped sheet is generally formed by crimping a substantially continuous web and cutting a plurality of crimped sheets from the crimped and gathered web. This material to be crimped, that is the continuous web, in the field of aerosol generating articles, can be tobacco cast leaves (TCL), polyactic acid (PLA), tow or others.

Methods and apparatuses for manufacturing a crimped web for use in an aerosol- generating article are known in the art. Known methods of manufacturing a crimped web generally involve feeding a substantially continuous web between a pair of interleaved rollers to apply a plurality of parallel, equidistant longitudinally extending crimp corrugations to the continuous web. The crimped web is subsequently gathered to form a continuous rod having a plurality of axial channels. The rod is then wrapped and cut into smaller segments to form an aerosol forming substrate or filter for an aerosol-generating article.

The crimping process creates various effects to the material which is pressed between the crimping rollers.

A first range of effects is related to the manufacturing processes, such as for example the fact that a crimped material is easily compressed into a rod that will then fit into the aerosol-generating articles.

Once the crimped material is compressed into a rod and added to the aerosol-generating article, a second range of effects is related to the crimping, such as the users' smoking experience. More specifically, the crimping process affects the air contact between external air and the aerosol generating article and the resistance to draw (RTD).

The crimping process is therefore very important for a correct manufacturing of the article and for obtaining the desired smoking experience. l However, a non-optimal or sub-optimal crimping process could weaken the crimped web of material as well as lower too much the RTD value due to the corrugations which are formed generally longitudinal to the axis of the rod and so they define "channels" for the air flow from the heating source up to the mouth of the user.

It would be desirable to provide a method and an apparatus for manufacturing a crimped sheet of material, preferably for an aerosol generating article, that allow to have a better control and increased flexibility on the aerosol generating article properties which are related to the crimping process.

According to a first aspect of the present invention, there is provided a method of manufacturing a crimped sheet of material for an aerosol-generating article, the method comprising the steps of: feeding a substantially continuous sheet of material to a set of crimping rollers in a transport direction, the set of rollers comprising a first roller and a second roller, at least one of the first or second roller being corrugated across at least a portion of its width; and crimping the substantially continuous sheet of material to form the crimped sheet of material by feeding the substantially continuous sheet of material between the first and second rollers in the transport direction of the sheet such that the corrugations of the first or second roller apply a first plurality of parallel crimp corrugations to a portion of the substantially continuous sheet of material, the first plurality of parallel crimp corrugations on the substantially continuous sheet of material forming a first angle with respect to the transport direction, while leaving another portion of the substantially continuous sheet of material free from crimp corrugations.

When forming a rod for an aerosol-generating article from a gathered crimped sheet manufactured using a conventional method, in which the crimp corrugations are parallel to the direction of motion of the sheet of material to be crimped, axial "channels" of air which can travel within the aerosol generating article are formed . This channel formation lowers the overall resistance to draw of the aerosol-generating article, since air drawn through the rod can easily pass along the axial channels. Advantageously, by crimping the continuous sheet of material such that the corrugations are "tilted" with respect to the direction of transport of the sheet of material, which usually corresponds to the axes of the final rod, an increased RTD can be obtained . In particular, usually, a specific RTD can be selected, defining a specific angle between the corrugation and the transport direction. Instead of a straight air channel in the rod, due to this angle presence, a tortuous path is defined, which may increase the RTD. The tortuous path may also increase the efficiency of the release of compounds, in particular by prolonging the time that compounds can be released, or by increasing the fraction of compound in the air, leaving the final product.

Further, the presence of at least one uncrimped portion (that is, a portion free of corrugations) of the sheet of material is useful for anchoring the crimped material, so as to avoid loss of shredded sheet of material. As used herein, the term "sheet" denotes a laminar element having a width and length substantially greater than the thickness thereof.

As used herein, the term "crimped" denotes a sheet or web with a plurality of corrugations. As used herein, the term "corrugations" denotes a plurality of substantially parallel ridges formed from alternating peaks and troughs joined by corrugation flanks. This includes, but is not limited to, corrugations having a square wave profile, sinusoidal wave profile, triangular profile, sawtooth profile, or any combination thereof. As used herein, the term "crimp corrugations" refers to the corrugations on a crimped sheet or web.

As used herein, the term "substantially interleave" denotes that the corrugations of the first and second rollers at least partially mesh. This includes arrangements in which the corrugations of one or both of the rollers are symmetrical or asymmetrical. The corrugations of the rollers may be substantially aligned, or at least partially offset. The peak of one or more corrugations of the first or second rollers may interleave with the trough of a single corrugation of the other of the first and second rollers. Preferably, the corrugations of the first and second rollers interleave such that substantially all of the corrugation troughs of one of the first and second rollers each receive a single corrugation peak of the other of the first and second rollers. As used herein, the term "longitudinal direction" refers to a direction extending along, or parallel to, the length of a web or sheet.

As used herein, the term "width" refers to a direction perpendicular to the length of a web or sheet, or in the case of a roller, parallel to the axis of the roller.

As used herein, the term "pitch value" refers to the lateral distance between the troughs at either side of the peak of a particular corrugation.

As used herein, the term "rod" denotes a generally cylindrical element of substantially circular or oval cross-section. As used herein, the terms "axial" or "axially" refer to a direction extending along, or parallel to, the cylindrical axis of a rod .

As used herein, the terms "gathered" or "gathering" denote that a web or sheet is convoluted, or otherwise compressed or constricted substantially transversely to the cylindrical axis of the rod .

As used herein, the term "amplitude value" refers to the height of a corrugation from its peak to the deepest point of the deepest directly adjacent trough.

As used herein, the term "corrugation angle" refers to the angle between the corrugation flanks of a particular corrugation. One, more, a majority or essentially all of the corrugations may be symmetrical about the radial direction. That is, the angle between each flank of a corrugation and the radial direction, or the "flank angle", may be the same and equal to half the corrugation angle. Alternatively, one or more of the corrugations are asymmetrical about the radial direction. That is, the flank angles of both flanks of a corrugation may be different. This statement can relate to a certain portion of the sheet material (so that the corrugations are different between two different portions of the sheet of material), or to more/to a majority of portions of the sheet material.

As used herein, the term "aerosol-generating article" refers to an article comprising an aerosol-forming substrate that is capable of releasing volatile compounds that can form an aerosol, for example by heating, combustion or a chemical reaction. As used herein, the term "aerosol-forming substrate" is used to describe a substrate capable of releasing volatile compounds, which can form an aerosol . The aerosols generated from aerosol- forming substrates of aerosol-generating articles according to the invention may be visible or invisible and may include vapours (for example, fine particles of substances, which are in a gaseous state, that are ordinarily liquid or solid at room temperature) as well as gases and liquid droplets of condensed vapours.

An aerosol-generating article may be a heated aerosol-generating article, which is an aerosol-generating article comprising an aerosol-forming substrate that is intended to be heated rather than combusted in order to release volatile compounds that can form an aerosol. A heated aerosol-generating article may comprise an on-board heating means forming part of the aerosol-generating article, or may be configured to interact with an external heater forming part of a separate aerosol-generating device. In order to produce a crimped sheet, the sheet of material, which can be for example tow, PLA or a sheet formed by homogenized tobacco material, is transported along a transport direction. The transport can be performed by any suitable means, for example by pulling the sheet of material via rollers. During the transport, the sheet or web of material is inserted between a pair of crimping rollers, named first and second rollers. One of the rollers of the pair includes a plurality of corrugations.

The rollers of the pair may both include corrugations. In this case, the corrugations of the first and second roller preferably interleave.

Only one of the two rollers may include corrugations, the other roller including a smooth cylindrical surface.

The two rollers may both include corrugations, but in non-corresponding portions, that is for each portion of the sheet of material which comes into contact with the rollers, only one of the rollers of the pair forms crimp corrugations on that portion of the sheet.

The corrugations on the first or on the second roller have preferably all the same pitch. More preferably, if corrugations are present both in the first and in the second roller, they all have the same pitch. Further, preferably, all corrugations in the first or in the second roller have the same amplitude.

The two rollers form crimp corrugations on the sheet or web of material having a given pattern. The pattern includes a first plurality of corrugations, realized one parallel to the other(s), which form an angle with respect to the direction of transport of the sheet. This angle is different from about 0°, that is, the corrugations are essentially not parallel to the direction of transport, but define an extension direction which is tilted to the direction of transport of the sheet. The angle between the corrugations and the direction of transport is comprised between 0° and 90°, where 0° is excluded . A line following a corrugation formed on the sheet of material and the direction of transport defines two supplementary angles. The angle considered herewith as a "first angle" between the corrugations and the direction of transport is the acute angle among the two.

Preferably, the first angle is comprised between about 10° and about 80°, more preferably between about 20° and about 70°, more preferably between about 30° and about 60°, more preferably between about 40° and about 50°, more preferably the first angle is of about 45°. Further, the two rollers leave a portion of the sheet uncrimped, that is, a portion of the sheet is essentially free from corrugations. Of course, the size of this uncrimped portion is bigger than the pitch value between two corrugations in the rollers. Preferably, the size of the uncrimped portion is at least twice the pitch value of the corrugations. "Essentially free" from corrugations means that in the uncrimped part of the sheet no corrugations are formed due to the rollers presence, however accidental bends and wrinkles - due to the nature of the sheet itself - might be present and the sheet surface might not be completely smooth.

Preferably, the uncrimped portion extends along the transport direction of the sheet, that is, considering the transport direction as an ordinate axis and as a coordinate axis an axis perpendicular to it, for each ordinate there is a range of coordinates in which the sheet is uncrimped .

The angle between the direction of transport and the crimp corrugations on the sheet can be varied and therefore the resulting RTD can be tailored depending on the requirements of the final aerosol generating article.

Indeed, the transport direction coincides preferably with the axis of a rod formed gathering the crimped sheet. Therefore forming inclined corrugations with respect to the transport direction means that the resulting rod includes "tilted" channels (defined by the gathered corrugations) for the air with respect to its axis. The flow of air within the rod is therefore more "difficult" with respect to a rod with axial channels. The level of this "difficulty", which define the RTD, depends on the angle or of the size of the corrugations, which can be selected during manufacturing.

Further, also the size of the uncrimped portion may determine the RTD because the bigger the size of such a portion, the smaller the number of channels (in the portion of the sheet showing corrugations) for the air in the final rod.

In addition, such uncrimped portion may also be used to anchor possible shredded material which may be formed in the process.

As used herein, "gathering" the crimped sheet can particularly include a folding process where two portions of the sheet can be put on top of each other by a folding-type operation along a usually straight line, or a rolling operation, where the initially flat sheet is brought into some kind of a coil-like form. Possibly, a combination of a folding and rolling processes can be used as well, where usually a folding-type operation is performed prior to rolling operation.

Preferably, the step of forming onto the sheet of material a first plurality of parallel crimp corrugations angled with respect to the transport direction includes forming the first plurality of parallel crimp corrugations and a second plurality of parallel crimp corrugations forming a second angle with the transport direction, and a third angle with the first plurality of parallel crimp corrugations. Preferably, the first angle is different from the second angle, so that the third angle is different from 0°. The meaning of the first angle "being different" from the second angle can relate to the magnitude of the two angles. The second angle is calculated as the first angle, that is, a line following a corrugation of the second plurality formed on the sheet of material and the direction of transport defines two supplementary angles. The angle considered herewith as a "second angle" between the corrugations of the second plurality and the direction of transport is the acute angle among the two. Preferably, the first angle is comprised between about 10° and about 80°, more preferably between about 20° and about 70°, more preferably between about 30° and about 60°, more preferably between about 40° and about 50°, more preferably the first angle is of about 45°. The third angle is calculated as the angle formed between a line following a corrugation of the first plurality and a line following a corrugation of the second plurality. Preferably, this third angle is greater than about 10°, more preferably greater than about 30°, preferably greater than about 50°, more preferably greater than about 70°, more preferably greater than about 80°, preferably of about 90°.

Using this design, a particularly wide variety of RTDs may be realised cheaply and easily.

Preferably, the portion of the substantially continuous sheet of material free from crimp corrugations forms a strip running substantially parallel to the transport direction. Such an arrangement may be particularly easy to realise with the presently proposed method of manufacturing a crimped sheet of material for an aerosol-generating article. Furthermore, with such a design, a possible following gathering step of the sheet of material may be realised particularly easily as well. Preferably, the portion of the substantially continuous sheet free from crimp corrugations is located between the first and the second plurality of parallel crimp corrugations. This way, a gathering operation, in particular a gathering operation comprising a folding operation, can be effectuated simply and effectively, if performed . Furthermore, the respective area free from crimp corrugations can be used as a distributing or collecting manifold for air entering or leaving the resulting aerosol- generating article.

Preferably, the portion of material free from crimp corrugations includes a reflection symmetry axis for the first and second plurality of parallel crimp corrugations. This way, usually an aerosol-generating article with a preferred behaviour with respect to RTD and release of compounds can be obtained. The two pluralities of parallel crimp corrugations show the same magnitude of an angle between the transport direction and the respective crimp corrugations, wherein the orientation of the angle is different

Preferably, the first plurality of parallel crimp corrugations extends along a first direction and the second plurality of parallel crimp corrugations extent along a second direction, wherein said first and second direction form a third angle wider than about 10°. This third angle wider than about 10° is the angle between the two sets of corrugations, that is, an angle between a line following a corrugation belonging to the first plurality and a corrugation belonging to the second plurality. Such angles wider than about 10° may usually result in an aerosol-generating article with advantageous behaviour. However, depending on the requirements, different upper limits can be used as well, like wider than about 30°, about 50°, about 70° or about 80°. Preferably the third angle is of about 90°.

Advantageously, the first or the second plurality of parallel crimp corrugations can form a first or second angle with the transport direction, the respective first or second angle being comprised between about 10° and about 80°. Such an interval of angles may result in an aerosol-generating article with advantageous behaviour, as well, for example regarding the overall smoking experience for the user. However, a different interval can be chosen as well, in particular an interval between about 20° and about 70°, between about 30° and about 60° or between about 40° and about 50°.

Particularly preferred, the first or second angle is of about 45°. Such an angle can result in a particularly preferred behaviour for the resulting aerosol-generating article.

Preferably, the substantially continuous sheet of material is one of: homogenized tobacco sheet, a plastic sheet or a sheet including cellulose. For such sheets, the presently proposed method can be particularly suited .

Preferably, the method includes the steps of gathering the crimped sheet of material, and forming a rod using the gathered crimped sheet of material. This way, an aerosol- generating article that suits the present-day market needs can be realised in an efficient and cheap way. In particular, an aerosol-generating article may be realised that resembles a traditional combustion-type aerosol-generating product, in particular a traditional cigarette. The "gathering" can particularly involve the previously described gathering methods. Advantageously, the method includes a step of wrapping the rod. Unwanted release of substances can be avoided, releases that might result in creation of unwanted stains when the product is carried along by and end-consumer. Further, a particularly advantageous guidance of air within the product can usually be realised .

Preferably, the method comprises the steps of cutting the continuous rod into a plurality of rod-shaped components, each rod-shaped component having a gathered crimped sheet formed from a cut portion of the crimped sheet, the crimp corrugations of the crimped sheet defining a plurality of channels in the rod-shaped component. The resulting products may suit the needs of the end-consumer particularly well.

According to a second aspect, the invention relates to a crimped sheet of material for use in an aerosol-generating article defining a longitudinal axis of extension, the crimped sheet of material including a portion having a first plurality of parallel crimp corrugations, the first plurality of parallel crimp corrugations forming a first angle with respect to the longitudinal axis of extension, and another portion free from crimp corrugations. The resulting crimped sheet of material can show the same features and advantages as previously described in the context of the presently proposed method for producing an aerosol-generating article, at least in analogy, as detailed with reference to the first aspect of the invention. Furthermore, the crimped sheet of material can be modified in the previously described sense as well, at least in analogy.

Preferably, the crimped sheet of material can include a further portion having a second plurality of parallel crimp corrugations forming a second angle with the longitudinal axis of extension, the first angle being different from the second angle.

Preferably, a ratio between a surface extension of the portions including the first and second plurality of parallel crimp corrugations and a surface extension of the portion free from crimp corrugations can be realised, where the ratio is preferably in the range of about 7 to about 20. More preferably, the ratio is comprised between about 8 to about 15, even more preferably between about 9 to about 12, most preferred of about 10. The ratio considered is the ratio of corrugated areas versus uncorrugated areas. These ratios have proven to be usually advantageous in first experiments. According to a third aspect, the invention relates to an apparatus to crimp a sheet of material to be used in an aerosol-generating article, said apparatus including a first and a second facing roller forming a gap therebetween, the first and the second roller being adapted to rotate about a first and second axis, respectively, and at least one of the first and second rollers including a corrugated surface portion having a first plurality of parallel corrugations forming locally a first angle with the first or second axis, the first angle being different from 0°, and a smooth surface portion free from corrugations. Such an apparatus can be particularly suitable for the production of a crimped sheet of material or an aerosol-generating article as previously described or for performing a method of manufacturing a crimped sheet of material for an aerosol-generating article as previously described according to the second or first aspect of the invention. It may show the same features and advantages as previously described, at least in analogy. Furthermore, it may be modified in the previously described sense, at least in analogy.

Preferably, the smooth surface portion has a cylindrical shape. This way, the portion of the substantially continuous sheet of material free from crimp corrugations can usually be manufactured very easily.

Preferably, the first of second roller includes a further corrugated surface portion having a second plurality of parallel corrugations forming locally a second angle with the first or second axis, the first angle being different from the second angle. This way, a crimped sheet of material, showing two different portions with corrugations, where the corrugations are arranged at different angles, can typically be produced easily and efficiently.

Preferably, the smooth surface portion is sandwiched between the corrugated surface portion and the further corrugated surface portion. This way, a crimped sheet of material comprising a set up like "corrugated portion - uncorrugated portion - corrugated portion" as previously suggested can usually be realised easily and efficiently.

Preferably, said first or second angle is comprised between about 10° and about 80°. More preferred, it can be of about 45°. Furthermore, deviating angles, as previously already suggested in the context of a method of manufacturing a crimped sheet according to the first aspect of the invention can be used as well.

According to a fourth aspect, the invention relates to an aerosol-generating article comprising a rod formed from a gathered crimped sheet according to the previously described design, wherein the crimp corrugations define a plurality of channels in the rod .

Such an aerosol-generating article may resemble a combustible smoking article, such as a cigarette. An aerosol-generating article may comprise tobacco. An aerosol- generating article may be disposable. An aerosol-generating article may alternatively be partially-reusable and comprise a replenishable or replaceable aerosol-forming substrate.

As used herein, the term "homogenised tobacco material" denotes material formed by agglomerating particulate tobacco. A homogenised tobacco material may be in the form of a sheet. The homogenised tobacco material may have an aerosol-former content of greater than 5 percent on a dry weight basis. The homogenised tobacco material may alternatively have an aerosol former content of between 5 percent and 30 percent by weight on a dry weight basis. Sheets of homogenised tobacco material may be formed by agglomerating particulate tobacco obtained by grinding or otherwise comminuting one or both of tobacco leaf lamina and tobacco leaf stems; alternatively, or in addition, sheets of homogenised tobacco material may comprise one or more of tobacco dust, tobacco fines and other particulate tobacco by-products formed during, for example, the treating, handling and shipping of tobacco. Sheets of homogenised tobacco material may comprise one or more intrinsic binders, that is tobacco endogenous binders, one or more extrinsic binders, that is tobacco exogenous binders, or a combination thereof to help agglomerate the particulate tobacco; alternatively, or in addition, sheets of homogenised tobacco material may comprise other additives including, but not limited to, tobacco and non- tobacco fibres, aerosol-formers, humectants, plasticisers, flavourants, fillers, aqueous and nonaqueous solvents and combinations thereof. The aerosol-forming substrate may be a solid aerosol-forming substrate. Alternatively, the aerosol-forming substrate may comprise both solid and liquid components. The aerosol- forming substrate may comprise a tobacco-containing material containing volatile tobacco flavour compounds, which are released from the substrate upon heating. Alternatively, the aerosol-forming substrate may comprise a non-tobacco material . The aerosol-forming substrate may further comprise an aerosol former. Examples of suitable aerosol formers are glycerine and propylene glycol. If the aerosol-forming substrate is a solid aerosol-forming substrate, the solid aerosol- forming substrate may comprise, for example, one or more of: powder, granules, pellets, shreds, spaghettis, strips or sheets containing one or more of: herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenised tobacco, extruded tobacco and expanded tobacco. The solid aerosol-forming substrate may be in loose form, or may be provided in a suitable container or cartridge. For example, the aerosol- forming material of the solid aerosol- forming substrate may be contained within a paper or other wrapper and have the form of a plug. Where an aerosol-forming substrate is in the form of a plug, the entire plug including any wrapper is considered to be the aerosol-forming substrate.

Optionally, the solid aerosol-forming substrate may contain additional tobacco or non- tobacco volatile flavour compounds, to be released upon heating of the solid aerosol- forming substrate. The solid aerosol-forming substrate may also contain capsules that, for example, include the additional tobacco or non-tobacco volatile flavour compounds and such capsules may melt during heating of the solid aerosol-forming substrate. Optionally, the solid aerosol-forming substrate may be provided on or embedded in a thermally stable carrier. The carrier may take the form of powder, granules, pellets, shreds, spaghettis, strips or sheets. The solid aerosol-forming substrate may be deposited on the surface of the carrier in the form of, for example, a sheet, foam, gel or slurry. The solid aerosol- forming substrate may be deposited on the entire surface of the carrier, or alternatively, may be deposited in a pattern in order to provide a non- uniform flavour delivery during use. In certain embodiments, at least part of the aerosol-forming substrate is formed from a gathered crimped sheet according to any of the embodiments described above. In such embodiments, the gathered crimped sheet may comprise a sheet of homogenised tobacco material. In certain embodiments, at least part of the aerosol-forming substrate is deposited on the surface of a carrier in the form of a gathered crimped sheet according to any of the embodiments described above.

The elements of the aerosol-generating article are preferably assembled by means of a suitable wrapper, for example a cigarette paper. A cigarette paper may be any suitable material for wrapping components of an aerosol-generating article in the form of a rod . Preferably, the cigarette paper holds and aligns the component elements of the aerosol- generating article when the article is assembled and hold them in position within the rod . Suitable materials are well known in the art.

Preferably, the aerosol-forming substrate is formed from or comprises a homogenised tobacco material having an aerosol former content of greater than 5 percent on a dry weight basis and water. For example the homogenised tobacco material may have an aerosol former content of between 5 percent and 30 percent by weight on a dry weight basis. An aerosol generated from such aerosol-forming substrates may be perceived by a user to have a particularly high temperature and the use of a high surface area, low resistance to draw aerosol-cooling element may reduce the perceived temperature of the aerosol to an acceptable level for the user.

The aerosol-generating article may be substantially cylindrical in shape. The aerosol- generating article may be substantially elongate. The aerosol-generating article may have a length and a circumference substantially perpendicular to the length. The aerosol-forming substrate may be substantially cylindrical in shape. The aerosol- forming substrate may be substantially elongate. The aerosol-forming substrate may also have a length and a circumference substantially perpendicular to the length. The aerosol-forming substrate may be received in the aerosol-generating device such that the length of the aerosol-forming substrate is substantially parallel to the airflow direction in the aerosol-generating device. The aerosol- cooling element may be substantially elongate.

The aerosol-generating article may have a total length between approximately 30 mm and approximately 100 mm. The aerosol-generating article may have an external diameter between approximately 5 mm and approximately 12 mm. The aerosol-generating article may comprise a filter or mouthpiece. The filter may be located at the downstream end of the aerosol-generating article. The filter may be a cellulose acetate filter plug . The filter is approximately 7 mm in length in one embodiment, but may have a length of between approximately 5 mm and approximately 10 mm. The aerosol-generating article may comprise a spacer element located downstream of the aerosol-forming substrate.

Further advantages of the invention will become apparent from the detailed description thereof with non-limiting reference to the appended drawings:

- Fig. 1 is in a schematic lateral view of an apparatus for manufacturing of a crimped sheet of material;

- Fig. 2 is a schematic front view of the crimping pair of rollers and the nip they are forming for crimping the material;

- Figs. 3a and 3b are schematic top views of crimped sheet of materials of different types; and - Fig. 4 is a schematic overview on a possible way how to produce aerosol- generating articles out of a crimped sheet of material.

In Fig. 1, the basic layout for an apparatus 1 for manufacturing a (partially) crimped sheet of material 7 for an aerosol-generating device is shown in a schematic lateral view.

The sheet of material is supplied by means of a first coil, namely a supply coil 2. On the supply coil 2, an "endless" sheet of a flat and thin layer of material 3 to be crimped using the apparatus 1 is provided . The material 3 can be a homogenised tobacco sheet or a plastic sheet and/or a cellulose-type sheet, on which some type of tobacco-like flavour compound is applied . It is to be understood that the sheet of material 3 that is wound up on coil 2 is strictly speaking not endless, of course. However, the overall length of the sheet of material can be several hundred metres and is therefore much longer than its width. Furthermore, it is possible that a handover mechanism between two consecutive supply coils 2 (not shown) is provided so that a continuous crimping process will be possible.

The sheet is coiled down from the supply coil 2 and enters the "main part" of the apparatus 1 as a single, flat layer of material 3. The processing of the flat layer of material 3 is done in a nip 6 which is formed between the upper roller 4 and the roller 5 by an appropriate placement of the 2 rollers 4, 5 at a certain distance. The width of the nip 6 is roughly in the range of the thickness of the entering layer of material 3. Depending on the current necessities of the processing process, the width of the nip 6 is typically slightly smaller than the thickness of the entering layer of material 3, so that the entering layer of material 3 is slightly compressed in the nip 6.

In the presently shown embodiment, the upper roller 4 and the lower roller 5 show a different outer surface (see also Fig. 2). Presently, only the upper roller 4 shows a structured outer surface, including a plurality of ridges or corrugations, while the lower roller 5 shows a smooth outer surface. However, it is also possible that a different arrangement is chosen, in particular that both the upper 4 and the lower roller 5 show a structured surface. Due to the design of the rollers 4, 5, in particular due to the design of the outer surfaces of the rollers 4, 5, the sheet of material 3 that passes through the nip will be partially corrugated. Namely, a certain fraction of the overall width of the essentially continuous sheet of material 3 will be corrugated, while another fraction of the overall width of the essentially continuous sheet of material 3 will remain flat (see Fig. 3a or 3b). The (partially) corrugated sheet 7 of material leaves the processing nip 6 at its other side. The corrugated sheet 7 is fed to the product coil 8, on which the processed and (partially) corrugated sheet 7 of material is wound up. The corrugation of the corrugated sheet 7 is shown in Fig. 1 in an exaggerated way.

In Fig . 2, the nip 6 that is formed by upper roller 4 and lower roller 5 "as seen by the entering sheet of material 3" is shown in more detail. In other words, the view of Fig . 2 is perpendicular to the view of Fig . 1. As can be seen in Fig. 2 particularly well, the upper roller 4 shows altogether three sections 9, 10, 11, where each section 9, 10, 11 shows a different structure of the outer surface of the cylindrical roller 4. Namely, in the centre part 9 (middle part when seen in an axial direction of the turning axis of roller 4), the outer surface of upper roller 4 shows a flat outer surface (i.e. the surface is not provided with a corrugation structure or the like). Therefore, the corresponding part of the sheet of material 3 that penetrates through the nip 6, remains unaltered (when assuming an initially flat and smooth surface of the sheet of material). Of course, depending on the width of the nip 6, even in this section 9, the sheet of material 3 that goes through the nip 6 might be compressed and/or - in case the entering sheet of material 3 shows a rough surface, for example - the sheet of material 7 leaving the nip 6 will have a smoothened surface. Contrary to the middle section 9, the outer sections 10, 11 of the upper roller 4 show a structure, namely a plurality of essentially parallelly arranged channels and protrusions, following each other, also called ridges. The angle of the lengthwise direction of the channels/protrusions is presently chosen to be about 45° with respect to the transport direction of the sheet of material 3 to be processed . In Fig . 2, the transport direction corresponds to a direction that is normal on the plane that is defined by the sheet of paper of the drawings. While the magnitude of the angle is identical in both sections 10 and 11, the direction of the angle is different in the two sections 10, 11. In particular, in the presently shown example, in left section 10, the channels/protrusions are arranged in a counter-clockwise direction, while they are arranged in a clockwise direction in right section 11 of upper roller 4 (with respect to the transport direction of the sheet of material 3).

In the presently shown example, the lower roller 5 comprises only an unstructured, smooth outer surface section 9. However, it is also possible that the lower roller 5 comprises a structure; in particular, a structure that corresponds to the structure of the upper roller 4 might be used.

Depending on the design of the rollers 4, 5, the sheet of material 7 that is leaving the nip 6 (i.e. the sheet of material 7 that is processed by apparatus 1 as indicated in Fig. 1) will show a corresponding surface structure. In Fig . 3a, the surface structure of the sheet of material 7a corresponds to the situation when a pair of rollers 4, 5 according to Fig. 2 has been used . Namely, three sections 12, 13, 14 are present, i.e. a smooth surface area 12 and two corrugated surface areas 13, 14 on the left and the right side of the sheet 7a. The corrugated areas show parallelly aligned channels/protrusions that are arranged at a 45° angle with respect to the transport direction of the sheet of material 7a. The direction of the 45° angle is different in the two surface areas 13, 14. In particular, in the corrugate area 13, a first plurality of corrugation is shown, which are aligned along a first axis 25. This axis 25 forms a first angle 21 with the direction of transport 23 of the sheet of material, which is indicated as an arrow in figure 3a. The first angle is of about 45°. In the corrugate area 14, a second plurality of corrugation is shown, which are aligned along a second axis 24. This axis 24 forms a second angle 20 with the direction of transport 23 of the sheet, which is indicated as an arrow in figure 3a. The second angle is of about 45°. A third angle 22 is defined between the first and the second axis, which is of about 90°. The width of the corrugated surface areas 13, 14 is presently chosen to be essentially identical, so that the sheet of material 7a shows a mirror symmetry with respect to a central axis that is parallel to the lengthwise direction of the sheet of material 7a.

However, depending on the exact design of the pair of rollers 4, 5 used, different surface designs of the sheet of material might be realised as well . Such an alternative design is shown in Fig. 3b. Here, the sheet of material 7b shows only a single corrugated area 17 on one side, while on the other side of the sheet of material 7b (when seen in a direction perpendicular to the lengthwise direction of the sheet of material 7b) a smooth area section 12 is shown.

In this case in the corrugate area 17, a first plurality of corrugation is shown, which are aligned along a first axis 25. This axis 25 forms a first angle 21 with the direction of transport 23 of the sheet of material, which is indicated as an arrow in figure 3a. The first angle is of about 45°. A single plurality of corrugation is present. Typically, the corrugated area 17 has/the corrugated areas 13, 14 have a larger width as compared to the uncorrugated area 12. In particular, a typical ratio of overall corrugated areas 13, 14 or 17 versus uncorrugated areas 12 is of about 10.

Only for completeness, it should be mentioned that a length of the sheet of material7a, 7b is much longer as compared to Figs. 3a, 3b. Therefore, in Figs. 3a or 3b, only a short section of the sheet of material 7a, 7b is shown.

In Fig . 4, finally, a sequence of intermediary steps for producing an aerosol-generating article is shown in a schematic way. As a start, a partially corrugated/partially uncorrugated sheet of material 7 (for example a sheet of material 7a, as shown in Fig. 3a), which can be obtained by apparatus 1, as shown in Fig. 1, is provided. This sheet of material 7 is rolled along an axis that this parallel to its length direction to form a rod 15. The rod 15 will show a significant length initially. Using a cutting tool (not shown), the rod 15 will be trimmed to a usable length (as shown in Fig . 4), therefore resulting in individual rods 15, showing a length of about 7 centimetres, about 8 centimetres, about 9 centimetres or about 10 centimetres, just to give an example. As a last step, the individual rods 15 will be wrapped up, using a wrapping sheet 16 (as shown on the right side in Fig . 4). The completely wrapped up rods 15 will be packed and distributed to dealers and ultimately to the end consumer.