Aerosol generating device with 3D printed ceramic cup and related manufacturing method

Abstract

The present invention relates to a heating assembly (10) for an aerosol generating device, comprising a heating chamber (12) having an opening for receiving an aerosol generating article, wherein the heating chamber comprises a tubular portion (16) made from a predetermined ceramic material to form a ceramic cup, and the ceramic cup is a slurry-based 3D printed ceramic cup corresponding to a mixture of the predetermined ceramic material and a polymer.

Description

Technical Field

[0001] The present invention relates to a heating assembly for an aerosol generating device and an aerosol generating device comprising such a heating assembly. The present disclosure is particularly applicable to portable aerosol generating devices that can be self - contained and operate at low temperatures.

[0002] In particular, the aerosol generating device according to the present invention is configured to operate with a tobacco article (also referred to as an aerosol generating article) comprising a solid substrate that can generate an aerosol when heated, for example. Thus, such a type of aerosol generating device, also known as a non - combustible heating device, is adapted to heat rather than burn the substrate by conduction, convection, and / or radiation to generate an aerosol for inhalation.

[0003] The present invention also relates to a method for manufacturing a heating chamber of a heating assembly for an aerosol generating device.

Background Art

[0004] (Also known as vaporizers) The popularity and use of risk - reduction devices or risk - modification devices have been rapidly increasing in recent years as an aid to assist habitual smokers who wish to quit smoking conventional tobacco products such as cigarettes, cigars, cigarillos, and roll - your - own tobacco. In contrast to burning tobacco in conventional tobacco products, various devices and systems for heating or warming vaporizable substances are available.

[0005] Commonly available risk reduction or risk modification devices are substrate-heated aerosol generating devices or non-combustion-heated devices. These types of devices typically generate aerosols or vapors by heating an aerosol generating substrate (i.e., an aerosol generating article) comprising damp tobacco leaves or other suitable vaporizable material to a temperature typically in the range of 150°C to 350°C. By heating the aerosol generating substrate rather than burning or igniting it, an aerosol is released that contains the components desired by the user but does not contain toxic and carcinogenic by-products from combustion and burning. Furthermore, since aerosols produced by heating tobacco or other vaporizable materials typically do not contain the burnt or bitter taste resulting from combustion and burning, which can be unpleasant to the user, the substrate does not require sugars and other additives that are typically added to such materials to make the smoke and / or vapor more palatable to the user's mouth.

[0006] Some known aerosol generating devices that operate with tobacco articles include a heater that consumes a significant amount of energy to raise the heater to a predetermined temperature and thus heat the tobacco article to a target temperature.

[0007] For heating an aerosol substrate, a heating assembly is known that comprises a heating chamber for receiving the aerosol substrate and a heating element for heating the heating chamber. The heating chamber is generally made of stainless steel. Both a thin-film metal heater for generating heat and a graphite layer for diffusing heat are wrapped around the heating chamber made of stainless steel, and the stainless steel cup holds the aerosol generating article.

[0008] However, this heating chamber is not entirely satisfactory. This is because it specifically requires a graphite layer, and while the graphite layer does not efficiently diffuse heat laterally compared to longitudinal heat diffusion in the axial direction, it is precisely this lateral heat diffusion that moves aerosol-generating items such as cigarettes. Furthermore, the stainless steel cup itself exhibits poor thermal conductivity.

[0009] Other heating chambers are made from materials that have properties that improve the heating of aerosol substrates, and consequently, improve the user experience.

[0010] For example, heating chambers made from ceramic materials are known, and therefore require considerable energy to reach the vaporization temperature. However, in heating chambers made from ceramic materials, heat is distributed uniformly, making it impossible to target specific areas of the heating chamber.

[0011] As a first solution, the heating chamber made from ceramic material is generally connected to additional components to manufacture a complete heater assembly, but the challenge here is joining the ceramic heating components to these additional components, which introduces an extra step and complicates the design.

[0012] As a second solution, the heating chamber made from ceramic material has a heating element within the ceramic, but such a configuration limits the manufacturing method to tape casting or cast molding, thus limiting the complexity of the geometry and the total wall thickness, and also increasing the energy consumption of the device. [Overview of the Initiative] [Problems that the invention aims to solve]

[0013] The present invention first aims to eliminate at least some of the shortcomings of the prior art. The present invention also aims to manufacture heating assemblies with low complexity and low cost while maintaining high performance and improved efficiency and providing improved sensory performance. [Means for solving the problem]

[0014] For this purpose, the present invention provides a heating assembly for an aerosol generating device, comprising a heating chamber having an opening for receiving an aerosol generating article, wherein the heating chamber is The ceramic cup comprises a tubular portion made from a predetermined ceramic material to form a ceramic cup, wherein the ceramic cup is a 3D printed ceramic cup based on a slurry corresponding to a mixture of the predetermined ceramic material and a polymer. Regarding heating assemblies.

[0015] In other words, the heating chamber comprises a ceramic cup that is at least partially formed by a tubular portion made of a predetermined ceramic material, and the ceramic cup is a 3D printed ceramic cup based on a slurry corresponding to a mixture of the predetermined ceramic material and a polymer.

[0016] It should be noted that the term “cup” will be obvious to those skilled in the art who are familiar with known heating assemblies for heating aerosol substrates, particularly heating assemblies comprising stainless steel cups, and means a “container” configured to hold an aerosol generating article. Such a container may be opened at one or both ends of the tube, as will be further described.

[0017] These characteristics make the proposed 3D-printed ceramic cup a suitable alternative to stainless steel cups, compared to conventional heating assemblies that typically have heating chambers made of stainless steel. In other words, because the ceramic material of the 3D-printed ceramic cup has a significantly higher thermal conductivity than that of stainless steel cups, a graphite layer may no longer be required in the heating assemblies proposed herein. Such thermal conductivity of the 3D-printed ceramic cup allows for efficient heat transfer in the longitudinal direction along the axial direction of the heating chamber. Indeed, the 3D-printed ceramic cup can store more thermal energy and heat the tobacco portion more uniformly. Despite the above, the proposed 3D-printed ceramic cup may also be equipped with a graphite sheet to further enhance the heat diffusion effect.

[0018] In addition, the high thermal conductivity of 3D printed ceramic cups allows them to have thicker walls compared to conventional heating assemblies, which typically feature heating chambers made from stainless steel. In fact, the thicker walls of 3D printed ceramic cups still provide the same heat transfer from the thin-film heating element to the tobacco item. Furthermore, considering that ceramics are very hard but more brittle, and therefore thicker walls improve their durability, the aforementioned thicker walls compared to conventional heating assemblies with heating chambers improve the durability of 3D printed ceramic cups.

[0019] The 3D printed ceramic cup is based on a slurry corresponding to the above-mentioned mixture of ceramic material and polymer, and can be easily printed into complex geometric shapes. To obtain a heated assembly, the 3D printed ceramic cup is enclosed within a thin-film heating element, eliminating the need to connect the thin-film heating element to additional components of the prior art, and eliminating the need for tape casting or cast molding required to insert the heating element into the ceramic.

[0020] In some embodiments, the 3D printed ceramic cup is - a predetermined shape, - a wall thickness adapted and optimized according to the type of the predetermined ceramic material, and exhibits at least one element belonging to the group including.

[0021] In fact, such a 3D printed ceramic cup can be easily printed into complex geometries (which is not always possible when using molding methods), and it is easier to adapt and optimize the wall thickness according to the type of the ceramic material. More precisely, with 3D printing, the complexity can be increased and the wall thickness can be made very thin over small areas. Therefore, according to these embodiments, 3D printed ceramic cups can, in most cases, provide additional features that cannot be obtained using conventional molding methods.

[0022] In some embodiments, the wall thickness is less than 1 mm and greater than or equal to 0.3 mm.

[0023] These features enable 3D printed ceramic cups to be easily printed and obtain a very thin wall thickness over small areas, but if the thickness is too thin (i.e., less than 0.3 mm), it cannot be printed.

[0024] In some embodiments, the heating assembly further includes a heating element configured to heat the tubular portion, and the heating element - is a thin film heating element, where the tubular portion is enclosed within the thin film heating element, a thin film heating element, and - an inductively heatable susceptor attached to the cup, and - a heater track directly printed on the cup belongs to the group including at least.

[0025] These features provide several heater options.

[0026] In some embodiments, the predetermined ceramic material is aluminum nitride.

[0027] Ceramic materials corresponding to Printed Aluminum Nitride (Printed AlN) have a thermal conductivity of 163.1 W / m·K (compared to 16.3 W·m). -1 ·K -1 Its thermal conductivity is actually significantly higher than that of stainless steel 316L, thereby enabling efficient heat transfer in the longitudinal direction and eliminating the need for a graphite layer to diffuse heat. In fact, in a graphite layer, thermal diffusion in the longitudinal direction is important, but thermal diffusion in the transverse direction (relative to the longitudinal axis) is insufficient, however, it is precisely this transverse thermal diffusion that is noteworthy as it moves aerosol-generating items such as cigarettes.

[0028] In other words, the proposed 3D-printed AlN ceramic cup is efficient at diffusing heat in all directions, while the stainless steel 316L cup, even when associated with a graphite layer, is poor in all directions and remains poor in the lateral direction, which is precisely the direction in which heat should be diffused.

[0029] Furthermore, such a thermal conductivity of 163.1 W / m·K for printed aluminum nitride (printed AlN) results in a larger wall thickness of 0.9 mm compared to 0.08 mm for a stainless steel 316L cup with respect to the same type of aerosol generating device, and the aforementioned larger wall thickness of 0.9 mm provides equivalent thermal resistance.

[0030] In some embodiments, the predetermined ceramic material is silicon carbide.

[0031] Silicon carbide (SiC) is a substitute for aluminum nitride (AlN) according to the embodiments described above. Other substitutes that can be used include silicon nitride (Si2N4) or beryllium oxide (BeO). In fact, such ceramic materials SiC, AlN, Si2N4, or BeO are ceramics that have higher thermal conductivity compared to, for example, aluminum oxide or zirconia, and are therefore more suitable for this application.

[0032] Aluminum nitride is preferred in this application for obtaining the above-mentioned 3D printed ceramic cup because it has a lower thermal conductivity than SiC.

[0033] According to some embodiments, the ceramic cup exhibits a ceramic wall thickness greater than or equal to a predetermined thickness threshold, and the predetermined thickness threshold is clearly not zero. In other words, if the predetermined thickness threshold is equal to zero, the ceramic cup exhibits a ceramic wall thickness greater than this predetermined thickness threshold.

[0034] These characteristics mean that while ceramics are very hard, they are also brittle, and therefore thicker walls improve the durability of 3D printed ceramic cups. Ideally, the thickness should be less than 1 mm, more ideally less than 0.7 mm, and even more ideally between 0.3 and 0.5 mm.

[0035] According to some embodiments, the thickness threshold depends on the type of the predetermined ceramic material.

[0036] In fact, since the ceramic cups are 3D printed, it is easier to adjust and optimize the thickness according to the type of ceramic material. However, 3D printing can increase complexity; while wall thickness can be made very thin over small areas, it may not be possible to print if the thickness is too thin.

[0037] According to some embodiments, the ceramic cup has an oval cross-section in the axial direction, and the oval cross-section is formed by two parallel flat surfaces joined by two curved surfaces, or by two straight surfaces having a small radius at the edge, or by any other feature configured to apply compression.

[0038] In fact, since the ceramic cups described above are 3D printed, such complex shapes can be formed reproducibly, which is impossible with conventional casting / molding processes. Using such 3D printed ceramic cups offers further advantages in heated tobacco devices with flat shapes compared to conventional heating assemblies that typically feature heating chambers made from stainless steel. Indeed, large feature areas for compression, along with the relatively thin wall thickness required for stainless steel cups to enable efficient heat transfer, are difficult to manufacture, structurally weak, and can flex during heating. As used herein, the term “feature areas for compression” encompasses all shapes and select points for compression around an aerosol-generating material rod, such as a tobacco rod.

[0039] In another aspect, the present invention relates to an aerosol generating device comprising a battery and a heating assembly as described above, wherein the heating element is powered by the battery.

[0040] Aerosol generating devices offer the same advantages as those described in relation to heating assemblies.

[0041] The present invention also relates to a method for manufacturing a heating chamber for a heating assembly for an aerosol generating device as described above, wherein the heating chamber has an opening for receiving an aerosol generating article, and the method comprises the steps of: 3D printing a tubular portion made from a predetermined ceramic material; and forming a 3D printed ceramic cup based on a slurry corresponding to a mixture of the predetermined ceramic material and a polymer.

[0042] According to some embodiments, the method further includes the step of associating the tubular portion with a heating element configured to heat the tubular portion, wherein the heating element - A thin-film heating element wherein the tubular portion is enclosed within the thin-film heating element, - An induction-heatable susceptor attached to the cup, - Heater track printed directly onto the cup It belongs to a group that includes at least [this].

[0043] According to some embodiments, the above step of 3D printing the tubular portion includes the following sequential substeps: - A substep of mixing the predetermined ceramic material of the tubular portion with a polymer to produce the slurry, - A substep of printing the slurry using 3D printing substantially equivalent to SLA printing, or by using a heat treatment related to the polymer as a filament, wherein the heat treatment maintains a predetermined shape; - A substep of debonding the above polymer at a predetermined temperature and fusing the individual ceramic particles suspended in the slurry together to sinter the above predetermined shape, thereby obtaining the above tubular portion as a finished part.

[0044] The present invention and its advantages are given merely as non-limiting examples and will be better understood by reading the following description with reference to the accompanying drawings. [Brief explanation of the drawing]

[0045] [Figure 1] This is a perspective view of a heating assembly according to a first embodiment of the present invention. [Figure 2] This is a perspective front view of another heating assembly according to another embodiment of the present invention. [Figure 3] This is a perspective cross-sectional view of another heating assembly according to another embodiment of the present invention. [Figure 4] This diagram corresponds to a flowchart of a method for manufacturing a heating chamber for a heating assembly used in an aerosol generating device. [Modes for carrying out the invention]

[0046] Before describing the present invention, it should be understood that the present invention is not limited to the structural details described below. It will be apparent to those skilled in the art who benefit from this disclosure that other embodiments are possible and that the invention can be implemented or carried out in various ways.

[0047] In the following, the expression "substantially equal" is understood to mean equal to plus or minus 10%, preferably plus or minus 5%.

[0048] As used herein, the terms “aerosol generating device” or “device” may include a vaping device for delivering an aerosol containing an aerosol for vaping to a user using a heater element, which is described in more detail below. The device may be portable. “Portable” may mean a device for use when held by a user. The device may be adapted to generate a variable amount of aerosol by activating a heater element over a variable amount of time (as opposed to a fixed amount of aerosol), which may be controlled by a trigger. The trigger may be user-activated, such as a vaping button and / or an inhalation sensor. The inhalation sensor may be highly sensitive to inhalation intensity and duration, and may enable the delivery of a variable amount of vapor (to mimic the smoking effect of conventional combustion-type smoking articles such as cigarettes, cigars, or pipes). The device may include a temperature control unit to drive the temperature of the heater and / or heated aerosol generating material (aerosol precursor) to a specific target temperature, and then maintain that temperature at the target temperature to enable efficient aerosol generation.

[0049] As used herein, the term “aerosol” may include suspended matter of vaporizable material as one or more solid particles, droplets, or gases. This suspended matter may be in a gas, including air. As used herein, aerosol generally refers to / may include vapor. An aerosol may contain one or more components of vaporizable material.

[0050] As used herein, the terms “vaporizable material” or “precursor” may refer to a smokeable material and an aerosol-forming agent, which may comprise, for example, nicotine or tobacco. Tobacco may take the form of various materials such as shredded tobacco, granular tobacco, tobacco leaves, and / or reconstituted tobacco. Suitable aerosol-forming agents include polyols (e.g., sorbitol, glycerol, and glycols such as propylene glycol or triethylene glycol), non-polyols (e.g., monohydric alcohols, acids such as lactic acid, glycerol derivatives, esters such as triacetin, triethylene glycol diacetate, triethyl citrate, glycerin, or vegetable glycerin). In some embodiments, the aerosol-generating agent may be glycerol, propylene glycol, or a mixture of glycerol and propylene glycol. The substrate may also contain at least one of a gelling agent, a binder, a stabilizer, and a humectant.

[0051] Figure 1 shows the heating assembly of the aerosol generating device (not shown in the figure).

[0052] The aerosol generating device is a non-combustion heating device, sometimes referred to as a tobacco vapor device or heated tobacco device, and comprises a heating assembly 10 and a battery (not shown) electrically connected to the heating assembly 10.

[0053] The heating assembly 10 is configured to receive an aerosol generating material, such as a tobacco rod, or an aerosol substrate. The heating assembly is also configured to convert electrical energy supplied by a battery into thermal energy. To achieve this objective, the heating assembly 10 is operable to heat the aerosol generating material rod rather than burn it, thereby generating vapor or aerosol for inhalation by the user. Naturally, those skilled in the art will understand that this aerosol generating device is merely an exemplary aerosol generating device according to the present invention. Other types and configurations of tobacco vapor products, vaporizers, or electronic cigarettes may be used as aerosol generating devices according to the present invention.

[0054] Tobacco articles that can be used with such types of aerosol generating devices can take various forms. Some may be elongated sticks, or any other suitable shape, such as a flat plate, as illustrated later with respect to Figures 2 and 3. However, the design of tobacco articles is often a trade-off between their aesthetics and heating efficiency.

[0055] The heating assembly 10 includes a heating chamber 12, also called a heat-conductive shell or cup, configured to hold an aerosol generating article, also called a consumable or aerosol substrate. In particular, the heating chamber 12 here defines a substantially cylindrical cavity or cup in which a rod of the aerosol substrate can be positioned.

[0056] The heating chamber 12 is tubular, for example, substantially cylindrical, and defines a central passage 13 that opens at a first end 14 of the heating chamber 12 and at a second end 15 of the heating chamber 12, which is axially opposite to the first end 14. In other words, the central passage 13 is accessible through openings from each of the first end 14 and the second end 15.

[0057] Alternatively, the central passage may have only one opening located at either the first or second end of the heating chamber 12.

[0058] During use, the user can insert the aerosol substrate through the opening of the heating chamber 12 so that the aerosol substrate is positioned within the heating chamber 12 and in contact with the inner surface of the heating chamber 12.

[0059] The length of the heating chamber 12 may be configured such that a portion of the aerosol substrate protrudes from the heating chamber 12 through the opening, i.e., outside the heating assembly 10, and can be received in the user's mouth.

[0060] According to the present invention, the heating chamber 12 includes a tubular portion 16 made from a predetermined ceramic material to form a ceramic cup, the ceramic cup being a 3D printed ceramic cup based on a slurry corresponding to a mixture of the predetermined ceramic material and a polymer.

[0061] The heating chamber 12 also includes a heating element configured to heat the tubular portion, and this heating element corresponds to a thin-film heating element.

[0062] The tubular portion 16 is enclosed within the thin-film heating element 18.

[0063] The tubular portion 16 here has a circular cross-section and a first end and a second end on the axial opposite side of the first end. In other words, the tubular portion 16 is tubular, for example, substantially cylindrical.

[0064] Alternatively, as will be shown later in relation to Figure 2, the tubular portion 16 comprises one or more flattening regions extending axially within the heating chamber 12.

[0065] The tubular portion 16 is made of a ceramic material, preferably aluminum nitride (abbreviated as AlN) in the illustrated example. Due to the configuration of the annular portion made of ceramic material, the first tubular portion 16 has a high thermal mass, which leads to good thermal penetration into the aerosol substrate, especially when the aerosol substrate contains tobacco. This makes it possible to improve sensory performance with a larger volume of vapor and a higher nicotine level when the aerosol substrate contains tobacco.

[0066] The thin-film heating assembly 18 includes a heating element 19 configured to function as a Joule heater when an electric current is supplied to it. In other words, the heating element 19 is configured to release heat in response to the flow of electric current. This physical phenomenon is sometimes called Joule heating, resistance heating, or ohmic heating. During use, power may be supplied to the heating element 19, for example, from a battery, so that the temperature of the heating element 19 rises and thermal energy is transferred throughout the heating chamber 12, more specifically to the tubular portion 16. The aerosol substrate received within the heating assembly is conductively heated by the heating chamber 16 to generate an aerosol for the user to inhale.

[0067] More precisely, the thin-film heater described above includes, for example, a metal heater track.

[0068] The metal heater described above has a thickness of 5 μm to 100 μm and is electrically insulated by one or more layers of insulating material such as polyimide. Typically, the metal heater track is sealed between two layers of polyimide. Each layer of insulating material has a thickness of approximately 20 μm to 50 μm. The thin-film heater is flexible due to the thin nature of all these aforementioned components and can be wrapped around other components and can be held and fixed in place by adhesive, by additional polyimide tape around it, or both.

[0069] In the example shown in Figure 1, the length of the film heating element 18 is shorter than the length of the tubular portion 16, and the film heating element 18 is located in the center along the longitudinal axis.

[0070] In fact, generally, some additional material remains in the tubular portion not covered by the thin-film heater 18, allowing for attachment to other components (not shown) and reducing the temperature before attachment to other components, which may not have the same high-temperature resistance as ceramics, such as PEEK or other polymers.

[0071] The position of the thin-film heating element 18 along the cup is not critical, but it is positioned in a way that correlates with the tobacco portion within the consumable inserted into the tubular section 16. This is because heating the tobacco is the goal.

[0072] Preferred dimensions for the 3D printed ceramic cup according to this disclosure are, for example, an inner height of 1.6–1.7 mm, an inner width of 12–15 mm, an inner edge radius of 0.1–0.5 mm, and an outer edge radius of 0.1–0.5 mm, in addition to the wall thickness, with a wall thickness of 0.3–1 mm. The smaller the amount of material that can be used, the less thermal energy required to heat the 3D printed ceramic cup, and the faster the set temperature can be reached during use. The mass of the 3D printed ceramic cup must be sufficiently high to ensure that the cup does not break due to brittleness.

[0073] The heating element 19 here surrounds the outer surface of the tubular portion 16 that forms the ceramic cup.

[0074] The heating element 19 is formed here as a meander or meandering pattern coating on the outer surface of the tubular portion 16 that forms the ceramic cup.

[0075] For example, the heating element 19 may be shaped by etching, masking, laser cutting, or stamping to form the illustrated pattern. Naturally, those skilled in the art will understand that the specific pattern formed by the heating element 19 may vary depending on the functional requirements of the heating assembly. The pattern forms an electrical path so that the current supplied from the battery to the heating element 19 during use travels along the electrical path, generating thermal energy. The heating element 19 can be made from any material that functions as a Joule heater when supplied with current, such as tungsten. Other materials with a coefficient of thermal expansion substantially matching that of ceramic materials may also be considered.

[0076] When the heating element 19 is powered by the current supplied by the battery of the aerosol generating device, the heating element 19 converts electrical energy into heat, and this heat is transmitted by conduction to the tubular portion 16 that forms the ceramic cup.

[0077] It should be noted that the thin-film heater providing the heating element 19 can be replaced by other types of heating elements, such as an inductively heated susceptor mounted on a heater track attached to a 3D-printed ceramic cup (not shown) or directly printed on a 3D-printed ceramic cup (not shown). For example, the inductively heated susceptor may take a tubular shape surrounding at least a portion of the 3D-printed ceramic cap.

[0078] Figure 2 shows that the proposed 3D printed ceramic cup can be adapted to various geometric shapes of aerosol generating devices. More specifically, Figure 2 shows that the aerosol generating device according to the present invention is configured to operate with tobacco articles, for example, flat-shaped tobacco articles.

[0079] Figure 2 shows two designs of such an aerosol generating device configured to operate with flat-shaped tobacco articles.

[0080] The first design 20 corresponds to a heated tobacco device having a substantially circular or elliptical cross-section.

[0081] In the front view of the first design 20 in Figure 2, the 3D ceramic cup 22 is in the cross section S in Figure 3. 20 As can be seen in the cross-sectional view A, it is enclosed within the thin-film heating element 24.

[0082] The second design 30 corresponds to a heated tobacco device having a substantially flat cross-section.

[0083] In the front view of the second design 30 in Figure 2, the 3D ceramic cup 32 is also shown in the cross section S in Figure 3. 30 As can be seen in the cross-sectional view B, it is enclosed within the thin-film heating element 34.

[0084] As shown in Figures 2 and 3, designs 20 and 30 both share a common feature, where the ceramic cups 22 and 32 have the same wall thickness all around (the thickness is not shown itself), have an oval cross-section in the axial direction, and the oval cross-section is formed by two parallel flat surfaces joined by two curved surfaces, or by two straight surfaces having a small radius at the edge, or by any other feature configured to apply compression.

[0085] Preferably, the ceramic material is made from aluminum nitride or silicon carbide.

[0086] The above 3D printed ceramic cups advantageously exhibit a ceramic wall thickness greater than or equal to a predetermined thickness threshold.

[0087] Optionally, the above thickness threshold depends on the type of the predetermined ceramic material.

[0088] In a specific example, if the above 3D printed ceramic cup is made from printed aluminum nitride exhibiting a thermal conductivity of 163.1 W / m·K (this is equivalent to 16.3 W·m -1 ·K-1 The thermal conductivity, which is actually significantly higher than that of stainless steel 316L, allows for efficient heat transfer in the longitudinal direction, eliminating the need for a graphite layer to dissipate heat.

[0089] Furthermore, such a thermal conductivity of 163.1 W / m·K for printed aluminum nitride (printed AlN) results in a larger wall thickness of 0.9 mm compared to 0.08 mm for a stainless steel 316L cup with the same design, and the aforementioned larger wall thickness of 0.9 mm still provides the same heat transfer from the thin-film heating element to the tobacco article.

[0090] The proposed 3D printed cup design 30 has additional advantages compared to conventional heating assemblies that are generally made of stainless steel and have a heating chamber exhibiting the same design shape. In fact, the large flat feature area required by stainless steel cups, which has a thin wall thickness of, for example, 0.075 mm, usually 50 μm to 200 μm, generally closer to 100 μm, is difficult to manufacture and structurally weak because it can flex during heating.

[0091] Herein, a method 40 for manufacturing a heating chamber for a heating assembly for an aerosol generating device, wherein the heating chamber has an opening for receiving an aerosol generating article, is described with reference to Figure 4, which shows a flowchart of the steps of the method.

[0092] In the first step 42, a tubular portion made from a predetermined ceramic material is 3D printed to form a slurry-based 3D printed ceramic cup corresponding to a mixture of the predetermined ceramic material and a polymer.

[0093] In the second step 44, the tubular portion is associated with a heating element configured to heat the tubular portion, and the heating element is - A thin-film heating element wherein the tubular portion is enclosed within the thin-film heating element, - An induction-heatable susceptor attached to the cup, - Heater track printed directly onto the cup It belongs to a group that includes at least [this].

[0094] As shown in the embodiment of Figure 4, step 42, which 3D prints the tubular portion, includes the following sequential substeps. - A substep 46 in which the predetermined ceramic material of the tubular portion is mixed with a polymer to produce the slurry, - Preferably, a substep 48 of printing the slurry using 3D printing substantially corresponding to SLA printing (wherein SLA represents Stereolithography Apparatus) or LCM printing (wherein LCM represents Lithography-based Ceramic Manufacturing), or by using a heat treatment related to the polymer as a filament, wherein the heat treatment maintains a predetermined shape. - Substep 50: The polymer is debonded at a predetermined temperature, and the individual ceramic particles suspended in the slurry are fused together to form the predetermined shape, thereby obtaining the tubular portion as a finished part.

[0095] LCM methods are preferred for high-precision and high-volume manufacturing, or for any future methods that improve precision and high-volume manufacturing.

[0096] For example, the slurry is pre-mixed in the bottle, and the mixture of ceramic and binder is predetermined according to the corresponding application.

[0097] For example (but not limited to), the slurry contains four compounds listed in the following percentages: AlN in a percentage of 50-100%, two polymers in 10-25% and 5-10% respectively, and a reactive curing agent in a percentage of less than 0.25%.

[0098] In other words, the slurry described above mainly comprises a ceramic material mixed with at least one small amount of polymer and a very small amount (i.e., less than 1%) of reactive curing agent.

[0099] The slurry is poured into the print bed of the 3D printer. Typically, the printer operates similarly to SLA (where SLA stands for StereoLitography Apparatus), where one layer of resin / slurry is UV-cured by a laser or other light source, and then another layer of resin / slurry is applied / moved to the area and cured again. These layers are typically microns to tens of microns thick. The duration depends on the layer size, the number of parts on the print bed, and the size of the part.

[0100] Alternatively, the slurry can be printed as a filament, but this method is less accurate than using a 3D printer that is essentially equivalent to SLA printing.

[0101] Regarding the sintering step 50, the typical sintering temperature for ceramic materials such as AlN is 1400-2000°C. The polymer is usually debonded at about 600°C, and then the individual ceramic particles suspended in the slurry are fused together during the sintering step 50.

[0102] More precisely, according to this example, AlN is typically sintered at temperatures above 1600°C, where all the polymer is burned away. In fact, if sintered at a lower temperature, e.g., 1100°C, all the polymer is still burned away, but the resulting ceramic is porous, which is not desired in this application. What is needed in this application is a high-density, low-porosity material with high thermal conductivity.

[0103] Unlike other ceramics, AlN typically requires sintering in an inert nitrogen environment. A slow temperature gradient is used to prevent thermal shock to the sintered part. This gradient varies depending on the size of the part being hardened, with smaller parts requiring a slower gradient rate. An example of a "standard" gradient rate is 10°C / min to a final temperature of, for example, 1700°C, which is then maintained for a long period (depending on the part size, but usually about 6-12 hours), and then slowly reduced to ambient conditions.

[0104] Those skilled in the art will understand that this disclosure is not limited to the embodiments described herein or the specific examples herein, and that the above embodiments and variations are also suitable for combining with one another to generate new embodiments of this disclosure.

[0105] According to the present invention, the heating assembly 10, more specifically the 3D printed ceramic cup, can be manufactured at low cost, is adaptable to various complex geometric shapes, and improves sensory performance and durability.

Claims

1. A heating assembly (10, 20, 30) for an aerosol generating device, The heating chamber (12) has an opening for receiving an aerosol-generating article, and the heating chamber is The ceramic cup comprises a tubular portion (16) made from a predetermined ceramic material to form a ceramic cup, wherein the ceramic cup is a 3D printed ceramic cup based on a slurry corresponding to a mixture of the predetermined ceramic material and a polymer. Heating assembly (10, 20, 30).

2. The aforementioned 3D printed ceramic cup A predetermined shape and The wall thickness is adapted and optimized according to the type of the predetermined ceramic material. A heating assembly (10, 20, 30) according to claim 1, exhibiting at least one element belonging to the group including the above.

3. The heating assembly (10, 20, 30) according to claim 1 or 2, wherein the wall thickness is less than 1 mm and 0.3 mm or more.

4. The heating element (19) is configured to heat the tubular portion, and the heating element is A thin film (18) heating element, wherein the tubular portion (16) is enclosed within the thin film (18) heating element, An induction heating susceptor attached to the cup, The heater track printed directly onto the cup and A heating assembly (10, 20, 30) according to any one of claims 1 to 3, belonging to the group which includes at least the following.

5. The heating assembly (10, 20, 30) according to any one of claims 1 to 4, wherein the predetermined ceramic material is aluminum nitride.

6. The heating assembly (10, 20, 30) according to any one of claims 1 to 4, wherein the predetermined ceramic material is silicon carbide.

7. The heating assembly (10, 20, 30) according to any one of claims 1 to 6, wherein the ceramic cup has a ceramic wall thickness greater than or equal to a predetermined thickness threshold.

8. The heating assembly (10, 20, 30) according to claim 7, wherein the thickness threshold depends on the type of predetermined ceramic material.

9. The heating assembly (10, 20, 30) according to any one of claims 1 to 8, wherein the ceramic cup has an oval cross-section in the axial direction, and the oval cross-section is formed by two parallel flat surfaces joined by two curved surfaces, or by two straight surfaces having a small radius at the edge, or by any other feature configured to apply compression.

10. An aerosol generating device comprising a battery and a heating assembly (10, 20, 30) according to any one of claims 1 to 9, wherein the heating element (19) is powered by the battery.

11. A method (40) for manufacturing a heating chamber for a heating assembly for an aerosol generating device, wherein the heating chamber has an opening for receiving an aerosol generating article, and the method comprises the steps of: 3D printing a tubular portion made from a predetermined ceramic material (42); and forming a 3D printed ceramic cup based on a slurry corresponding to a mixture of the predetermined ceramic material and a polymer (40).

12. The step (44) further includes associating the tubular portion with a heating element configured to heat the tubular portion, wherein the heating element A thin-film heating element, wherein the tubular portion is enclosed within the thin-film heating element, An induction heating susceptor attached to the cup, The heater track printed directly onto the cup and The method according to claim 11 (40), which belongs to the group comprising at least the following.

13. The step (42) of 3D printing the tubular portion, A substep (46) involves mixing the predetermined ceramic material of the tubular portion with a polymer to produce the slurry, A substep (48) of printing the slurry using 3D printing substantially equivalent to SLA printing, or by using a heat treatment related to the polymer as a filament, wherein the heat treatment maintains a predetermined shape; Substep (50) to obtain the tubular portion as a finished part by debonding the polymer at a predetermined temperature and fusing the individual ceramic particles suspended in the slurry together to form the predetermined shape. The method according to claim 11 or 12, comprising a series of (40).

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