Moulding method and moulding unit for forming an object

Abstract

A method comprises: - an inserting step for inserting a dose (2) made with a mouldable material between a female half-mould (6; 106; 206) and a male half-mould (7; 107; 207); - a forming step for forming an object (3) by moving at least one half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) towards the other half-mould selected from the male half-mould (7; 107; 207) or the female half-mould (6; 106; 206) along a moulding direction (D) in order to press the dose (2) between the male half-mould (7; 107; 207) and the female half-mould (6; 106; 206). A locking step is furthermore provided for locking a portion of the dose (2) between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207) before the end of the forming step. A half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) comprises a movable central part (9; 109; 209), which is shiftable between a forward position (PA) and a retracted position (PR). The movable central part (9; 109; 209) is in the forward position (PA) during the locking step and is in the retracted position (PR) at least at the end of the forming step.

Description

[0001] Moulding method and moulding unit for forming an object

[0002] The invention relates to a moulding method and a moulding unit for forming an object by pressing a dose of mouldable material.

[0003] The mouldable material with which the object is made may be a natural fibre-based material, for example a cellulose-based material, in the form of airlaid (substantially dry or humidified), fluff, aggregated powders or the like. The mouldable material may comprise a limited quantity of fibres of synthetic polymeric material, mixed with the natural fibres.

[0004] Alternatively, the mouldable material with which the object is made may be a synthetic polymeric material, for example polyethylene, polyethylene terephthalate, polypropylene, polyvinyl alcohol or other material.

[0005] The mouldable material with which the dose is made may be a multi-layer material, obtained by combining layers of similar materials or layers of dissimilar materials. In the latter case it is possible to combine one or more layers of natural fibre-based materials, for example cellulose, with one or more layers of synthetic polymeric materials, for example in the form of films or of fibres.

[0006] The object formed by the moulding method and the moulding unit according to the invention may be a packaging component, in particular having a concave shape, for example a cap, a capsule, a container, a preform. However, this condition is not necessary and other types of objects may be formed with the moulding method and the moulding unit according to the invention.

[0007] In order to form an object of mouldable material by pressing, it is known that a dose of mouldable material is positioned between a male half-mould and a female half-mould of a moulding unit. When the dose is released between the male half-mould and the female half-mould, said half-moulds are in a spaced apart position. Then, the male half-mould and the female half-mould are moved towards each other to gradually deform the dose and to compress the dose until the desired object is obtained. A drawback of the prior art moulding units is that, while the male half-mould and the female half-mould are moved towards each other along a moulding direction to compress the dose, the latter may move in an unwanted way transversally to the moulding direction. In this way the dose may be positioned off-centre between the male half-mould and the female halfmould, which compromises the quality of the object formed.

[0008] Another drawback of prior art moulding units is that, in some cases, when the mouldable material which forms the dose is deformed between the male half-mould and the female half-mould, excessive stretching of some portions of the dose of mouldable material may occur. This excessive stretching may generate a thickness that is too low in some zones of the object formed, or even cause breaks at some points of the object formed. US 3305158 discloses a method for forming a hollow container by thermoforming a preform made with an orientable synthetic plastic material. After heating the preform to its orientation temperature, a peripheral portion of the preform is locked in a mould cavity. A central portion of the preform is then displaced towards the inside of the mould cavity relative to the locked peripheral portion. At the same time, pressure is applied to both surfaces of the central portion to obtain a lateral flow of synthetic plastic material in the central portion and create a lateral wall of the container, which is formed between the locked peripheral portion and the central portion which is being displaced.

[0009] The preform is locked at the peripheral portion thereof between a lip protruding from a base of the mould and two movable sectors which form an outer surface of the lateral wall of the container.

[0010] EP 2828171 discloses a method for forming a paper tray by deep-drawing. The tray comprises a bottom and upwardly expanding side walls around the bottom. The side walls of the tray are shaped to form a plurality of circumferential steps.

[0011] The tray disclosed in EP 2828171 is formed in an apparatus comprising an upper moulding tool and a lower moulding tool. Each moulding tool is provided with concentric frames, which allow the steps to be made in the side walls.

[0012] The tray is formed from a paperboard bland or web which, at the beginning of the forming step, is locked between the upper moulding tool and the lower moulding tool at a peripheral edge thereof.

[0013] A drawback of the method disclosed in US 3305158 is that, by firmly locking the preform at the peripheral edge thereof, the preform material may be broken when being deformed to form the lateral wall of the container. That is to say, it may occur that the lateral wall of the container is lacerated, because the material forming the container is significantly stretched while it is locked both at the peripheral portion and at the central portion thereof.

[0014] This drawback would be worsened if the preform, instead of being made of orientable synthetic plastic material, were made of a natural-fibre based material, which is less deformable and tends to be lacerated more easily than the orientable synthetic polymeric material.

[0015] Similar drawbacks may occur in the method disclosed in EP 2828171 .

[0016] An object of the invention is to improve the moulding methods and the mouldings units for obtaining objects by pressing doses, the doses being made with a natural fibre-based material and / or with a synthetic polymeric material.

[0017] Another object is to provide a moulding method and a moulding unit for obtaining an object by pressing a dose, in which it is possible to better control the position of the dose between a male half-mould and a female half-mould of the moulding unit.

[0018] A further object is to provide a moulding method and a moulding unit for obtaining an object by pressing a dose, in which the risk of the dose being positioned off-centre while the male half-mould and the female half-mould are moved towards each other is minimised.

[0019] Another object is to provide a moulding method and a moulding unit by means of which it is possible to obtain good quality objects by pressing doses made of natural fibre-based material and / or of synthetic polymeric material.

[0020] Another object is to prevent the dose of mouldable material from being made too thin or even lacerated when it is deformed between a male halfmould and a female half-mould of the moulding unit.

[0021] In a first aspect of the invention, a method is provided comprising the steps of:

[0022] - inserting a dose made with a mouldable material between a female half-mould and a male half-mould;

[0023] - forming an object, by moving at least one half-mould selected from the female half-mould or the male half-mould towards the other halfmould selected from the male half-mould or the female half-mould along a moulding direction for pressing the dose between the male half-mould and the female half-mould; wherein a locking step is provided for locking a portion of the dose between the female half-mould and the male half-mould before the end of the forming step, and wherein a half-mould selected from the female half-mould or the male half-mould comprises a movable central part, which is displaceable between a forward position and a retracted position, the movable central part being in the forward position during the step of locking a portion of the dose, the movable central part being in the retracted position at least at the end of the forming step.

[0024] By locking a portion of the dose, it is possible to keep the dose in the correct position between the male half-mould and the female half-mould, preventing lateral shifting. In this way it is possible to prevent, or in any case to minimise, the risk of the dose being positioned in an off-centre position before the forming step or during the forming step. That helps to obtain a good quality formed object.

[0025] The movable central part, which is arranged in the forward position during the step of locking a central portion of the dose and then reaches the retracted position, allows a sort of pre-forming of the dose to be carried out. This helps to prevent excessive thinning of the dose during the forming step, which increases the uniformity in the thickness of the object formed.

[0026] In an embodiment, in the locking step, a central portion of the dose is locked between the movable central part, arranged in the forward position, and the half-mould facing the movable central part, selected from the male halfmould or the female half-mould.

[0027] In this case the movable central part has a locking function, together with the half-mould facing it, and it acts on the central portion of the dose to prevent lateral displacement of the dose, that is to say, displacement of the dose transversally to the moulding direction.

[0028] The dose has a peripheral portion delimited by a perimetral edge.

[0029] In an embodiment, in the locking step, the peripheral portion of the dose is left free whereas the central portion of the dose is locked between the movable central part, arranged in the forward position, and the half-mould facing the movable central part, selected from the male half-mould or the female half-mould.

[0030] Leaving the peripheral portion of the dose free during the locking step is especially useful if the dose is shaped to obtain a concave object.

[0031] Indeed, by leaving the peripheral portion of the dose free, the risk is reduced of tearing the mouldable material as the latter is deformed, for example to generate a lateral portion of the object.

[0032] Even if the central portion of the dose is locked between the movable central part and the half-mould facing the movable central part, the material surrounding the central portion has anyway a certain freedom to move while it is being shaped, because no locking action is provided at the peripheral portion of the dose and especially at the perimetral edge of the dose.

[0033] This prevents the material surrounding the central portion from being subjective to excessive stress, which might cause breakage thereof. In an alternative embodiment, in the locking step, a peripheral portion of the dose is locked between the female half-mould and the male half-mould, whilst a central portion of the dose is resting on the movable central part, arranged in the forward position.

[0034] In this case, the movable central part has a supporting function, for supporting the dose from the initial moments of the forming step, which helps keep the dose in a correct position, whilst a peripheral part of the dose is locked between a component arranged outside the movable central part and the half-mould facing it, so as to prevent lateral displacement of the dose.

[0035] In an embodiment, during the locking step, said portion of the dose is locked by clamping it between the female half-mould and the male half-mould, without however reaching a final degree of compaction.

[0036] “Final degree of compaction” indicates the extent of compression which is reached, at the end of the forming step, in the part of the object which is formed from said portion of the dose (i.e. from the portion of the dose which is clamped between the male half-mould or the female half-mould during the locking step).

[0037] The portion of the dose which was locked during the locking step is compressed to reach the final degree of compaction after a further portion of the dose has been deformed, the further portion being adjacent to the portion of the dose which was locked during the locking step.

[0038] In other words, during the locking step, the portion of the dose which was locked between the male half-mould and the female half-mould is not completely compressed.

[0039] The portion of the dose which was locked between the male half-mould and the female half-mould is subjected to a further compression after a further portion of the dose, adjacent to the one which was locked, has started to be deformed.

[0040] This avoid excessive stress inside the dose during the forming step. In the locking step, a pressure sufficient to avoid substantial lateral displacement of the dose is applied on the portion of the dose locked between the male half-mould and the female half-mould. However, in the locked portion, the mouldable material of the innermost layers of the dose still has a certain ability to move. The material forming the innermost layers of the dose may therefore follow movement of the further portion of the dose, adjacent thereto, which is deformed during the forming step. This minimizes the risk of tearing the mouldable material as the latter is shaped for forming the object, in particular for forming a lateral wall of the object.

[0041] In an embodiment, the female half-mould has a forming cavity for forming an outer surface of the object, the forming cavity having a bottom surface arranged transversally to the moulding direction, the bottom surface being at least partly made on the movable central part.

[0042] In this embodiment the movable central part is therefore included in the female half-mould.

[0043] In an embodiment, the male half-mould has a punch delimited by an end surface, the end surface being at least partly made on the movable part.

[0044] In this embodiment, the movable central part is included in the male halfmould.

[0045] In an embodiment, a half-mould selected from the female half-mould or the male half-mould, for example the female half-mould, comprises a plurality of sectors which are movable transversally to the moulding direction for defining a variable-volume forming region.

[0046] The sectors may initially be positioned at a relatively large distance from each other. That makes it possible to process also doses of mouldable material having large dimensions compared with the dimensions of the object formed.

[0047] Moreover, the variable-volume forming region may have, initially, a shape that is very different from the shape of the finished object. That makes it possible to use doses with a simple shape, which are easy to obtain, even for making objects having a rather complicated structure.

[0048] Providing a variable-volume forming region initially having a volume greater than the object to be made reduces the risk that the mouldable material might interact in an unwanted way with the male half-mould or the female half-mould, which could compromise the quality of the object obtained. Therefore it is possible to significantly improve the step of inserting the dose between the male half-mould and the female half-mould.

[0049] In an embodiment, the male half-mould comprises a compensating element positionable at a variable distance from the female half-mould for defining a dimension of the of the object parallel to the moulding direction, said dimension being variable between successive objects depending on the mass of the corresponding dose.

[0050] Owing to the compensating element, it is possible to process doses having a mass which may vary, within predetermined limits, in any case making good quality objects.

[0051] In an embodiment, the portion of the dose is locked between the female half-mould and the male half-mould as a consequence of a mutual movement between facing parts of the female half-mould and the male halfmould, said mutual movement occurring parallel to the moulding direction. In a second aspect of the invention, there is provided a moulding unit for making an object by pressing a dose of mouldable material, the moulding unit comprising a female half-mould and a male half-mould, at least one half-mould selected from the female half-mould or the male half-mould being movable towards the other half-mould selected from the male halfmould or the female half-mould along a moulding direction for pressing the dose between the male half-mould and the female half-mould, and wherein a half-mould selected from the female half-mould or the male half-mould comprises a movable central part, which is displaceable parallel to the moulding direction between a forward position for locking a portion of the dose between the movable central part and a half-mould, selected from the male half-mould or the female half-mould, which is facing the movable central part, and a retracted position in which said object is formed.

[0052] In a third aspect of the invention, there is provided a moulding unit for making an object by pressing a dose of mouldable material, the moulding unit comprising a female half-mould and a male half-mould, at least one half-mould selected from the female half-mould or the male half-mould being movable towards the other half-mould selected from the male halfmould or the female half-mould along a moulding direction for pressing the dose between the male half-mould and the female half-mould, and wherein a half-mould selected from the female half-mould or the male half-mould comprises a movable central part, which is displaceable parallel to the moulding direction between a forward position for receiving the dose and a retracted position in which said object is formed, the other half-mould selected from the male half-mould or the female half-mould comprising a locking element for locking a peripheral portion of the dose before the object is completely formed.

[0053] In an embodiment of the moulding unit according to the second aspect of the invention or the third aspect of the invention, a half-mould selected from the female half-mould or the male half-mould comprises a plurality of sectors that are movable transversely to the moulding direction between an enlarged configuration and a forming configuration for defining a variable volume forming region.

[0054] In an embodiment of the moulding unit according to the second aspect of the invention or the third aspect of the invention, the male half-mould comprises a compensating element which is positionable at a distance from a transversal surface delimiting a forming cavity of the female half-mould, said distance depending on the mass of the dose. It is thus possible to form objects having a dimension, measured along the moulding direction, which is greater the greater the mass of the dose is.

[0055] Owing to the second and third aspect of the invention, it is possible to form good quality objects, minimising the dose positioning errors in the moulding unit.

[0056] The invention can be better understood and implemented with reference to the accompanying drawings, which illustrate several example, non-limiting embodiments of it, in which:

[0057] Figure 1 is a schematic cross-section, showing a moulding unit for forming an object in an open configuration, in which a dose is positioned between a female half-mould and a male half-mould;

[0058] Figure 2 is a view like that of Figure 1 , showing the moulding unit in a subsequent configuration, in which the dose is locked between a movable central part of the female half-mould and the male half-mould;

[0059] Figure 3 is a view like that of Figure 1 , in a configuration in which a transversal wall of an object is formed;

[0060] Figure 4 is a view like that of Figure 1 , in a configuration in which a lateral wall of the of the object is formed;

[0061] Figure 5 is a view like that of Figure 1 , in a final forming configuration;

[0062] Figure 6 is a schematic cross-section, showing an alternative embodiment of a moulding unit in an open configuration, in which a dose is positioned between a female half-mould and a male half-mould;

[0063] Figure 7 is a view like that of Figure 6, showing the moulding unit in a subsequent configuration, in which the dose is locked between a movable central part of the male half-mould and the female half-mould;

[0064] Figure 8 is a view like that of Figure 6, in a configuration in which a transversal wall of an object is formed;

[0065] Figure 9 is a view like that of Figure 6, in a configuration in which a lateral wall of the of the object is formed;

[0066] Figure 10 is a view like that of Figure 6, in a final forming configuration;

[0067] Figure 11 is a schematic cross-section, showing another alternative embodiment of a moulding unit in an open configuration, in which a dose is positioned between a female half-mould and a male half-mould; Figure 12 is a view like that of Figure 1 1 , showing the moulding unit in a subsequent configuration, in which the volume of a variable-volume forming region is reduced by moving a plurality of sectors;

[0068] Figure 13 is a view like that of Figure 11 , in a configuration in which the dose is locked between the female half-mould and the male half-mould;

[0069] Figure 14 is a view like that of Figure 11 , in a configuration in which the dose is deformed between the female and male half-moulds;

[0070] Figure 15 is a view like that of Figure 1 1 , in a final forming configuration. Figures 1 to 5 show a moulding unit 1 for forming an object 3 by pressing a dose 2 made of mouldable material.

[0071] In the example illustrated, the dose 2 is made with a natural fibre-based mouldable material, in particular with a cellulose-based material. The dose 2 may contain for example a quantity of cellulose equal to 80% of its weight. The dose 2 may also contain a limited quantity of fibres of synthetic polymeric material, mixed with the natural fibres.

[0072] The dose 2 may be in the form of airlaid, that is to say, obtained starting from a natural fibre-based material in a dense form which is defibrated in a mill to separate the fibres of which it is composed. The latter are then joined to form the airlaid structure using an air flow to carry the fibres.

[0073] The dose 2, for example in the case in which it is obtained starting from an airlaid structure, is usually in a substantially dry form, in which case its water content is less than 15% by weight, for example less than 10% by weight. However, it is also possible that the dose 2 has a higher moisture content, for example from 5% to 80% of its weight. In this case, the water present in the dose 2 derives from the fact that, after the fibres are already interconnected to form the airlaid structure, water is added to the latter, for example to help solidification and forming of the object obtained starting from the dose 2, or as a basic liquid containing one or more additives.

[0074] The natural fibre-based dose 2 may even be in the form of fluff, or aggregated powders. Alternatively, the mouldable material with which the object is made may be a synthetic polymeric material.

[0075] It is also possible to use doses made with a multi-layer material, comprising two or more layers made with materials which are similar or not similar. The multi-layer material may for example comprise at least one natural fibrebased layer, for example cellulose-based, and at least one layer of synthetic polymeric material, in the form of films or fibres.

[0076] The mouldable material with which the dose is made may be a non- extrudable material, in particular if that material contains natural fibres. Indeed materials of this type cannot reach the high temperatures necessary for extrusion without being damaged, for example burnt.

[0077] The dose 2 initially has a substantially flat shape. For example, the dose 2 may have a circular, or square, or rectangular, or other shape in plan view. If an object having a concave shape is to be obtained, the dose 2 may have a shape which is not flat, in particular a concave shape. That makes it easier to centre the dose 2 in the moulding unit 1 and makes it easier to form the desired object, since the shape of the dose 2 is more similar to the shape of the object than in the case of a flat dose.

[0078] The object 3 formed by pressing the dose 2 may have a three-dimensional shape, in particular a concave shape. In the example illustrated, the object 3 is cup-shaped. Some examples of objects which can be made in the moulding unit are containers, capsules, caps for containers, lids, preforms for containers, trays for packaging and the like.

[0079] The object 3 may have a lateral wall 4, closed at one end by a transversal wall 5. The moulding unit 1 comprises a female half-mould 6 and a male half-mould 7, facing each other and aligned along a moulding direction D. In the example illustrated, the moulding direction D is vertical.

[0080] At least one half-mould selected from the female half-mould 6 or the male half-mould 7 is movable relative to the other half-mould selected from the male half-mould 7 or the female half-mould 6 along the moulding direction D, in order to press the dose 2 and to form the object 3. In the example illustrated, the female half-mould 6 is movable along the moulding direction D for moving towards the male half-mould 7 or moving away from the latter, whilst the male half-mould 7 remains in a fixed position along the moulding direction D.

[0081] In an alternative embodiment, the female half-mould 6 could be fixed along the moulding direction D, whilst the male half-mould 7 is movable along the moulding direction D for moving towards, or moving away from, the female half-mould 6. It is also possible to move both the male half-mould 7 and the female half-mould 6 along the moulding direction D.

[0082] The female half-mould 6 and / or the male half-mould 7 can be moved along the moulding direction D by means of an actuator not illustrated, for example of the hydraulic, mechanical or electrical type.

[0083] In the example illustrated, the female half-mould 6 is positioned below the male half-mould 7. However, this condition is not necessary and, in an embodiment not illustrated, the female half-mould 6 could be positioned above the male half-mould 7, or the female half-mould 6 and the male halfmould 7 could be aligned along a horizontal or oblique moulding direction.

[0084] The female half-mould 6 has a forming cavity 8 for forming an outer surface of the object 3.

[0085] The forming cavity 8 has a bottom surface 10, or transversal surface, arranged transversally, in particular perpendicularly, relative to the moulding direction D. The bottom surface 10 is intended for forming the transversal wall 5 of the object 3 from the outside.

[0086] The forming cavity 8 also has a lateral surface 11 intended for forming the lateral wall 4 of the object 3 from the outside.

[0087] The moulding unit 1 has a moulding axis Z which extends parallel to the moulding direction D.

[0088] The lateral surface 1 1 extends around the moulding axis Z. The moulding unit 1 comprises a movable central part 9, which can be shifted along the moulding direction D.

[0089] In the embodiment shown in Figures 1 to 5, the movable central part 9 is included in the female half-mould 6. However, this condition is not necessary and, as will be described in more detail below, the movable central part 9 could alternatively be included in the male half-mould.

[0090] The movable central part 9 is displaceable parallel to the moulding direction D between a forward position PA, shown in Figures 1 and 2, and a retracted position PR, shown in Figures 3 to 5.

[0091] The female half-mould 6 comprises a base 13 in which the movable central part 9 is housed. More specifically, the movable central part 9 is housed in a hole 14 made in the base 13, in such a way that a movement of the movable central part 9 and the base 13 relative to each other along the moulding direction D is allowed.

[0092] In the forward position PA, the movable central part 9 projects from the base 13 towards the half-mould facing it, that is to say, towards the male halfmould 7. In the forward position PA, the movable central part 9 is intended to receive the dose 2. More specifically, the movable central part 9 is delimited, transversally to the moulding direction D, by a contact surface 12 suitable for receiving the dose 2. The dose 2 may be conveyed towards the moulding unit 1 by a conveying element not illustrated and released onto the movable central part 9 while the latter is in the forward position PA. The dose 2 may in particular be placed resting on the contact surface 12, which may be an upper surface of the movable central part 9.

[0093] The contact surface 12 may be a flat surface, in such a way that the dose 2 can be stably positioned on the contact surface 12.

[0094] In the retracted position PR, the forming of the object 3 is completed. However, the movable central part 9 may move into the retracted position PR even before the object 3 is completely formed, as will be described in more detail below. The movable central part 9 is slidable between the forward position PA and the retracted position PR owing to a driving element not illustrated. In an embodiment, the movable central part 9 may be slidable between the forward position PA and the retracted position PR owing to a spring system. The movable central part 9 may have a widened portion 16 at an end thereof opposite the contact surface 12. The widened portion 16 may be delimited by a stop surface 17 which extends transversally to the moulding direction D.

[0095] Along the hole 14 of the base 13 a shoulder 15 may be provided against which the stop surface 17 of the movable central part 9 can abut in the forward position PA. That ensures that the positioning of the base 13 and of the movable central part 9 relative to each other in the forward position PA is constant.

[0096] Defined on the base 13 there is a forming surface 18, in particular having an annular shape. The forming surface 18 partly defines the bottom surface 10 of the forming cavity 8. The bottom surface 10 of the forming cavity 8 is furthermore defined by the contact surface 12 of the movable central part 9. In the retracted position PR, the contact surface 12 may be flush with the forming surface 18, in such a way that the movable central part 9 and the forming surface 18 together form the transversal wall 5 of the object 3 from the outside.

[0097] In the forward position PA, the movable central part 9 projects from the base 13.

[0098] The female half-mould 6 further comprises a plurality of sectors 19, which are movable transversally, in particular perpendicularly, to the moulding direction D for defining a variable-volume forming region 20.

[0099] The sectors 19 are delimited by respective shaping surfaces 21 suitable for making contact with the mouldable material which forms the dose 2 for at least partly forming the lateral wall 4 of the object 3 from the outside. The number of sectors 19 may be arbitrarily selected. For example, it is possible to have four sectors 19, but even a number of sectors 19 other than four.

[0100] The sectors 19 are movable between an enlarged configuration C1 , shown in Figures 1 and 2, and a forming configuration C2, shown in Figure 5. In the forming configuration C2, the variable-volume forming region 20 defined between the sectors 19 and the bottom surface 10 has substantially the same shape as the shape of an outer surface of the object 3. In contrast, in the enlarged configuration C1 , the variable-volume forming region 20 has dimensions greater than the external dimensions of the object 3.

[0101] In the example illustrated, the sectors 19 are also configured to restingly receive the dose 2 before the latter is shaped between the male half-mould 7 and the female half-mould 6. The sectors 19 are delimited by a receiving surface 29, which in the example illustrated is an upper surface of the sectors 19, arranged for supporting the dose 2 released onto the female half-mould 6. The receiving surface 29 is facing the male half-mould 7. The receiving surface 29 may be substantially flat.

[0102] The male half-mould 7 comprises a punch 22 for forming the object 3 from the inside. The punch 22 is delimited by an end forming surface 23 for forming the transversal wall 5 of the object 3 from the inside. The punch 22 is also delimited by a lateral forming surface 24 for forming the lateral wall 4 of the object 3 from the inside. The lateral forming surface 24 extends around the moulding axis Z, whilst the end forming surface 23 is positioned transversally to the moulding axis Z.

[0103] In an embodiment, the punch 22 may be made in multiple parts.

[0104] The male half-mould 7 further comprises a compensating element 25 positionable in such a way that it is floating relative to the punch 22 along the moulding direction D. The compensating element 25 is positioned outside the punch 22. Depending on the structure of the object 3 to be formed, there may be one or more intermediate components present between the punch 22 and the compensating element 25.

[0105] The compensating element 25 may have a tubular shape, so as to house the punch 22 inside it.

[0106] The compensating element 25 may have a tubular body 26 provided with a forming end 27. The latter, which may also have a tubular shape, has a smaller thickness than the thickness of the tubular body 26. In this way it is possible to insert the forming end 27 between the punch 22 and the sectors 19 for forming an edge zone 28 of the object 3, as shown in Figure 5.

[0107] The compensating element 25 is positionable, relative to the punch 22, at a height which is variable depending on the mass of the dose 2. Indeed, the mass of the dose 2 may vary, within a limited range, due to many factors such as the tolerances of the components which make up the apparatus in which the moulding unit 1 is inserted, the not always constant properties of the mouldable material which forms the dose 3, any wear or other phenomena. By positioning the compensating element 25 at a variable height relative to the punch 22 depending on the mass of the dose 2, it is possible to obtain objects 3 having a height H, shown in the enlarged detail of Figure 5, which varies depending on the mass of the dose 2. Starting from a dose 2 having a relatively large mass, an object 3 is obtained whose height H is greater than in the case of another object 3 formed starting from a dose 2 having a relatively small mass. If the mass of the dose 2 varies within a predetermined tolerance, the height H variations in the object 3 are not problematic.

[0108] During operation, the moulding unit 1 is initially positioned in an open configuration Q1 , shown in Figure 1 , in which the female half-mould 6 is spaced apart from the male half-mould 7.

[0109] The movable central part 9 is arranged in the forward position PA, in which it projects relative to the base 13. The movable central part 9 may be positioned in such away that, in the forward position PA, the contact surface 12 of the movable central part 9 is at the same level as the receiving surface 29 of the sectors 19, along the moulding direction D. In this way, the receiving surface 29 and the contact surface 12 define a resting plane onto which the dose 2 can be released.

[0110] The sectors 19 are positioned in the enlarged configuration C1 , in which the dimensions of the variable-volume forming region 20 perpendicularly to the moulding direction D are greater than the dimensions of the object 3 perpendicularly to the moulding direction D.

[0111] In the male half-mould 7, the compensating element 25 is arranged in a backward position relative to the end forming surface 23 of the punch 22, in which the forming end 27 of the compensating element 25 is positioned a relatively large distance from the end forming surface 23 of the punch 22.

[0112] A dose 2 of mouldable material, for example cellulose, is positioned in the moulding unit 1 , in particular in the female half-mould 6, by a conveying element not illustrated.

[0113] If the dose 2 is made with a natural fibre-based material, for example cellulose, the dose 2 may be cut from a sheet or web of natural fibre-based material, or formed as a discrete dose by pre-compacting the natural fibres. The dose 2 comprises a central portion 30 and a peripheral portion 31 . The peripheral portion 31 is delimited by a perimetral edge 40.

[0114] The central portion 30 of the dose 2 is placed resting on the contact surface 12 of the movable central part 9, whilst the peripheral portion 31 of the dose 2 is placed resting on the receiving surface 29 of the sectors 19.

[0115] In this way, when the dose 2 is inserted into the moulding unit 1 , the dose 2 is supported both at its central portion 30 and at its peripheral portion 31 , which prevents unwanted deformation of the dose 2 and helps the dose 2 to keep a flat and stretched out shape, optimum for the subsequent forming step.

[0116] Then, at least one half-mould selected from the female half-mould 6 or the male half-mould 7 is moved towards the other half-mould selected from the male half-mould 7 or the female half-mould 6, so as to bring the dose 2 into contact with the punch 22. In the example illustrated, that is done by moving the female half-mould 6 upwards, whilst the male half-mould 7 remains in a fixed position along the moulding direction D. In this way a locking configuration Q2 is reached, shown in Figure 2, in which the dose 2 is locked between the female half-mould 6 and the male half-mould 7. More precisely, in the locking configuration Q2 the dose 2 is locked between the movable central part 9 and the punch 22.

[0117] The locking configuration Q2 is reached at the end of a locking step.

[0118] In order to reach the locking configuration Q2, a relative movement occurs parallelly to the moulding direction D between the two components which lock the central portion 30 of the dose 2, namely the movable central part 9 and the half-mould facing the movable central part 9.

[0119] Clamping the dose 2 between the movable central part 9 and the half-mould facing it, that is to say, the male half-mould 7, prevents lateral displacement of the dose 2, that is to say, prevents the dose 2 from displacing transversally to the moulding direction D. This prevents the dose 2 from being positioned off-centre in the forming cavity 8. In this way the quality of the object 3 formed is improved.

[0120] Continuing to move the female half-mould 6 towards the male half-mould 7, the central portion 30 of the dose 2 is compressed between the punch 22 and the movable central part 9, as shown in Figure 3. In this way the thickness of the mouldable material is reduced, and its density is increased, creating the transversal wall 5 of the of the object 3.

[0121] While the female half-mould 6 is moved towards the male half-mould 7 to compress the dose 2, the base 13 is moved forward towards the punch 22 more than the movable central part 9. The effect of this relative movement is that the movable central part 9 gradually projects less inside the forming cavity 8. In other words, the movable central part 9 gradually projects less between the sectors 19, until the retracted position PR is reached, shown in Figure 3, in which the contact surface 12 is flush with the forming surface 18 of the base 13, that is to say, the contact surface 12 is placed at the same height as the forming surface 18 along the moulding direction D.

[0122] Due to the interaction between the punch 22 and the female half-mould 6, the dose 2 is deformed in such a way as to adopt a concave shape and gradually pushed inside the forming cavity 8. In the configuration shown in Figure 3, the dose 2 is no longer resting on the receiving surface 29 of the sectors 9. The latter start to move towards each other, gradually reducing the dimensions of the variable-volume forming region 20, so as to act on the peripheral portion 31 of the dose 2 to form the lateral wall 4 of the object 3. Figure 4 shows a compacting configuration Q3, in which the base 13 and the movable central part 9 have reached their final position relative to the punch 22. The transversal wall 5 of the object 3 was formed in this way, starting from the central portion 30 of the dose 2, which was pressed until a definitive degree of compaction was reached. The sectors 19 also reached their forming configuration C2, that is to say, their final configuration relative to the punch 22. The lateral wall 4 was substantially formed in this way, except in an upper edge zone thereof, which has not yet interacted with mould parts.

[0123] At this point the compensating element 25, which had already started to be moved towards the end surface 23 of the punch 22, is inserted between the sectors 19 and the punch 22, so as to compact the mouldable material forming the edge zone 28 of the object 4. This situation is shown in Figure 5, in which the moulding unit 1 is in a final forming configuration Q4. The compensating element 25 is pushed towards the movable central part 9 until the desired degree of compaction of the object 3 is reached. Depending on the actual mass of the dose 2, which may vary within a predetermined range, the final position of the compensating element 25 relative to the movable central part 9 may vary. Consequently, the height H of the lateral wall 4 of the object is affected by the mass of the dose 2. A larger dose 2 causes a greater height H than a dose 2 having a smaller mass. Limited variations in the height H do not compromise product functionality and are therefore acceptable.

[0124] The object 3 has now reached its definitive shape and can be extracted from the moulding unit 1 , which can be returned to the open configuration Q1 shown in Figure 1 to receive a new dose 2 to be formed.

[0125] The sequence with which the transversal wall 5 and the lateral wall 4 are formed by compacting the respective portions of the dose 2 may be different from what is shown in Figures 1 to 5. It is possible to form first the transversal wall 5 by compacting the mouldable material between the punch 22, the movable central part 9 and the base 13 and then to form the lateral wall 4 by compacting the mouldable material between the punch 22 and the sectors 19. It is also possible to form first the lateral wall 4 and then the transversal wall 5, or to simultaneously compact the mouldable material in the lateral wall 4 and in the transversal wall 5.

[0126] In the example shown in Figures 1 to 5, the dose 2 was locked between the movable central part 9 and the punch 22 before starting the forming step, that is to say, while the dose 2 still had a flat shape and before the dose 2 was significantly deformed between the male half-mould 7 and the female half-mould 6. It is also possible to lock the dose 2 between the movable central part 9 and the half-mould facing it when the forming of the dose 2 has already started, for example when the dose 2 is already adopting a concave shape because of the interaction between the female half-mould 6 and the male half-mould 7.

[0127] It is noticed that, during the locking step, the central portion 30 of the dose 2 is locked between the movable central part 9 and the half-mould facing the movable central part 9, which in this case is the male half-mould 7. On the other hand, the peripheral portion 31 , and in particular the perimetral edge 42, remains free to move during the locking step. This prevents the dose 2 from being broken or torn when the mouldable material is deformed between the movable central part 9 and the sectors 19 for forming the lateral wall 4 of the object 3. The peripheral portion 31 is indeed free to follow movement of the central portion 30 without being constrained at the perimetral edge 40 thereof.

[0128] It is furthermore noticed that, during the locking step, the mouldable material which forms the central portion 30 is clamped between the movable central part 9 and the half-mould facing the movable central part 9 without however reaching the final degree of compaction. This is clearly apparent by comparing Figure 2 with Figure 5. It is indeed clear that the central portion 30 of the dose 2 has, at the end of the locking step, a thickness (shown in Figure 2) greater than the thickness of the transversal wall 5 in the object 3 (shown in Figure 5).

[0129] After the central portion 30 was locked between the movable central part 9 and the half-mould facing the movable central part 9, the peripheral portion 31 , which is adjacent to the central portion 30, starts to be deformed to originate the lateral wall 4, owing to the relative movement occurring between the movable central part 9 and the half-mould facing the movable central part 9. The central portion 30 of the dose 2 thus continues to be compressed while the peripheral portion 31 is deformed, until the final degree of compaction is reached.

[0130] Thus, the fibres in the central layers of the central portion 20 still have a certain ability to move even at the end of the locking step, which makes possible, for those fibres, to better adapt to the mouldable material deformation while the lateral wall 4 is formed.

[0131] Figures 6 to 10 show a moulding unit 101 according to an alternative embodiment. The moulding unit 101 differs from the moulding unit 1 mainly because it comprises a movable central part 109 which is included in a male half-mould 107, rather than being included in the female half-mould as was the case in the embodiment shown in Figures 1 to 5. What was previously described with reference to the moulding unit 1 shown in Figures 1 to 5 shall be understood to also apply to the moulding unit 101 , unless otherwise indicated.

[0132] The male half-mould 107 of the moulding unit 101 comprises a punch 122 made at least in two parts, that is to say, comprising a forming sleeve 32 which houses the movable central part 109. The forming sleeve 32 is delimited by the lateral surface 24 which, similarly to what was described with reference to Figures 1 to 5, extends around the moulding axis Z for forming the lateral wall 4 of the object 3 from the inside. The forming sleeve 32 is also delimited, transversally to the moulding axis Z, by a front forming surface 33 arranged for forming a part of the transversal wall 5 of the object 3 from the inside.

[0133] The movable central part 109 is delimited by a contact surface 12 suitable for making contact with the dose 2 for locking it against the half-mould facing the movable central part 109, that is to say, against the female half-mould 106. The contact surface 12 is arranged transversally, in particular perpendicularly, to the moulding axis Z. The contact surface 12 may be a flat surface.

[0134] The movable central part 109 is displaceable parallel to the moulding direction D between a forward position PA, shown in Figures 6 and 7, and a retracted position PR, shown in Figures 8 to 10. In the forward position PA, the movable central part 109 projects from the forming sleeve 32 towards the female half-mould 107. In the retracted position PR, the movable central part 109 is completely housed inside the forming sleeve 32. In the retracted position PR, the contact surface 12 of the movable central part 109 is flush with the front forming surface 33 of the forming sleeve 32. In the retracted position PR, the contact surface 12 and the front forming surface 33 together define an end forming surface 123, which may optionally be flat, for forming the transversal wall 5 of the object 3 from the inside. In the embodiment shown in Figures 6 to 10 too, the movable central part 109 may have a widened portion 116 at an end thereof opposite the contact surface 12. The widened portion 116 is delimited by a stop surface 1 17 which extends transversally to the moulding direction D. Inside the forming sleeve 32 there may be a shoulder 1 15 against which the stop surface 117 of the movable central part 109 can abut in the forward position PA. That ensures that the positioning of the forming sleeve 32 and of the movable central part 109 relative to each other in the forward position PA is constant. The male half-mould 107 further comprises a compensating element 25, which is not described in detail because it is similar to the compensating element 25 described with reference to Figures 1 to 5.

[0135] The female half-mould 106 comprises a base 113 delimited by a forming surface 118 for forming the transversal wall 5 of the object 3 from the outside. The forming surface 1 18 is facing the male half-mould 107 and, in the example illustrated, is substantially flat and arranged transversally, in particular perpendicularly, to the moulding axis Z.

[0136] The female half-mould 106 further comprises a plurality of sectors 19, movable between an enlarged configuration C1 shown in Figures 6 to 8 and a forming configuration C2 shown in Figures 9 and 10. The sectors 19 will not be described in detail again because what was previously described with reference to the sectors 19 shown in Figures 1 to 5 also applies to the sectors 19 shown in Figures 6 to 10.

[0137] During operation, as shown in Figure 6, the female half-mould 106 and the male half-mould 107 are initially spaced apart from each other and are arranged in an open configuration Q1. The sectors 19 are in the enlarged configuration C1 , whilst the movable central part 109 projects from the forming sleeve 32 and is in the forward position PA. A dose 2, for example made with a natural fibre-based material, is positioned on the receiving surface 29 of the sectors 19 by a conveying element not illustrated. At least one half-mould selected from the female half-mould 106 or the male half-mould 107 is moved towards the other half-mould selected from the male half-mould 107 or the female half-mould 106. In the example illustrated, the female half-mould 106 is moved along the moulding direction D towards the male half-mould 107. While the female half-mould 106 is moved in this way, a central portion 30 of the dose 2 makes contact with the movable central part 109 which projects from the forming sleeve 32. The movable central part 109 deforms the dose 2, which adopts a concave configuration and is pushed into the forming cavity 8, towards the bottom surface 10. At a certain point, a locking configuration Q2 shown in Figure 7 is reached, in which the dose 2 is locked between the movable central part 109 and the half-mould facing it, that is to say, the female half-mould 106. More specifically, the central portion 30 of the dose 2 is in contact with the contact surface 12 of the movable central part 109 and with the forming surface 1 18 of the base 113.

[0138] In the locking configuration Q2, the movable central part 109 and the halfmould facing it clamp the dose 2, preventing the dose 2 from being displaced along a direction transversal to the moulding direction D, which keeps the dose 2 correctly centred in the moulding unit 101 even during forming.

[0139] It should be noticed that, whilst in the embodiment shown in Figures 1 to 5, the locking configuration Q2 was reached while the dose 2 still had a flat structure, in the embodiment shown in Figures 6 to 10 the locking configuration Q2 is reached during the forming step of the dose, that is to say, after the dose 2 has already been deformed to give it a concave shape. In the locking configuration Q2 shown in Figure 7, the sectors 19 are still arranged in the enlarged configuration C1 , whilst the movable central part 109 is still arranged in the forward position PA.

[0140] Then, the female half-mould 106 is moved further towards the male halfmould 107, whilst the movable central part 109 is moved backwards into the forming sleeve 32, until it reaches the retracted position PR in which the contact surface 12 of the movable central part is aligned with the front forming surface 33 of the forming sleeve 32 and together they define the end forming surface 123. In this way, the mouldable material which forms the central portion 30 of the dose 2 is compacted between the movable central part 109 and the base 1 13, creating the transversal wall 5 of the object 3. This situation is shown in Figure 8.

[0141] The sectors 19 are now brought from the enlarged configuration C1 to the forming configuration C2, as shown in Figure 9, to compact also the mouldable material which forms the peripheral portion 31 of the dose 2 and to create the lateral wall 4 of the object 3. It should be noticed that the sectors 19 can be moved from the enlarged configuration C1 to the forming configuration C2 after the transversal wall 5 has been completely formed or while the transversal wall 5 is formed.

[0142] Finally, the compensating element 25 is inserted between the punch 122 and the sectors 19 to shape the edge zone 28 of the object 3, thereby compressing along the moulding direction D the mouldable material which forms the lateral wall 4 and positioning itself at a distance H from the base 3 which depends on the mass of the dose 2 which is processed.

[0143] Forming of the object 3 is completed in this way.

[0144] Also in the example shown in Figures 6 to 10, the central portion 30 of the dose 2 is locked between the movable central part 109 and the half-mould facing the movable central part 109, due to a relative movement parallelly to the moulding direction D between the movable central part 109 and the half-mould facing the movable central part 109.

[0145] Also in the example shown in Figures 6 to 10, at the end of the locking step (i.e. when the locking configuration Q2 shown in Figure 7 is reached), the mouldable material has not yet reached a final degree of compaction in the central portion 30. The mouldable material of the central portion 30 continues to be compressed even after the locking step is finished. In particular, the mouldable material of the central portion 30 reaches a final degree of compaction at the end of the forming step, after also the peripheral portion 31 has been at least partially deformed.

[0146] Finally, also in the example shown in Figures 6 to 10, the locking step only affects the central portion 30. At the end of the locking step, the peripheral portion 31 , and in particular the perimetral edge thereof, is still free to move. Even if, in the previous description, reference was made to a dose 2 comprising a natural fibre-based material, moulding units like those shown in Figures 1 to 10 may also be used for processing doses made of synthetic polymeric material.

[0147] Figures 10 to 15 show a moulding unit 201 according to an alternative embodiment. The moulding unit 201 is particularly suitable for processing a dose 2 made of synthetic polymeric material, even if that moulding unit is theoretically also usable in combination with doses made with a natural fibre-based material. The dose 2 may, for example, have a quadrangular shape in plan view, in particular square or rectangular, but even circular, oval or another shape. The dose 2 may be flat or concave.

[0148] The moulding unit 201 comprises a female half-mould 206 which, as in the case of the moulding unit 1 shown in Figures 1 to 5, has a movable central part 209 which can be moved along the moulding direction D between a forward position PA, shown in Figures 11 to 13 and a retracted position PR, shown in Figure 15. The movable central part 209 is similar to the movable central part 9 described with reference to Figures 1 to 5 and will not be described in detail again.

[0149] As in the case of Figures 1 to 5, the movable central part 209 is housed inside a base 213 and is slidable inside a hole 214 of the base 213.

[0150] In the case of Figures 1 to 5, the movable central part 9 engages in the hole 14 with shape coupling, since the movable central part 9 and the hole 14 both have a cylindrical shape. In the case of Figures 10 to 15, the hole 214 not only has the function of housing the movable central part 209, but helps to form the object 3. More specifically, the hole 214 is delimited by a shaping lateral surface 38 for forming the lateral wall 4 of the object 3 from the outside. Since the object 3 to be formed is a capsule delimited by a lateral wall 204 with frustoconical shape, the shaping lateral surface 38 which delimits an upper portion of the hole 214 is frustoconical, whilst the movable central part 209 is cylindrical. A free space 34 is thus defined between the movable central part 209 and the base 213. However, at its lower end, the hole 214 has a guide portion 35 which may be cylindrical for shapingly engaging with the movable central part 209 and for guiding the movable central part 209 during the movement along the moulding direction D.

[0151] The female half-mould 206 further comprises the sectors 19, which are structurally similar to the sectors 19 previously described, even if, as will be described in more detail below, when the dose 2 is inserted into the moulding unit 201 , the sectors 19 shown in Figures 10 to 15 do not support the dose 2, but merely have a containment function.

[0152] The moulding unit 201 further comprises a male half-mould 207 comprising a punch 222 arranged inside a locking sleeve 36. The punch 222 is delimited by the end forming surface 23 and by the lateral forming surface 24, as already described with reference to Figures 1 to 5. The punch 222 is configured to shape an inner surface of the object 3.

[0153] The locking sleeve 36 has a locking surface 37 facing the female half-mould 206. The locking surface 37 is configured to lock the dose 2 in contact with the base 213 while the mouldable material is pressed to form the object 3. The locking surface 37 is arranged transversally, in particular perpendicularly, to the moulding direction D, and may be a flat annular surface.

[0154] The punch 222 and the locking sleeve 306 are movable relative to each other, in the sense that one component selected from the punch 222 or the locking sleeve 36 moves relative to the other component selected from the locking sleeve 36 or the punch 222 with a linear translating movement along the moulding direction D. In the example illustrated, the locking sleeve 36 moves relative to the punch 222 due to the thrust applied by the female halfmould 206.

[0155] The punch 222 may be positioned in a backward position PB, shown in Figures 11 to 13, in which a forming end of the punch 222 delimited by the end forming surface 23 and by the lateral forming surface 24 is arranged inside the locking sleeve 36. The punch 222 may also be positioned in a projecting position PS, shown in Figure 15, in which the forming end of the punch 222 projects from the locking sleeve 36 to penetrate the forming cavity 8.

[0156] The male half-mould 207 does not comprise the compensating element 25 described with reference to Figures 1 to 10.

[0157] During operation, the moulding unit 201 is initially in the open configuration Q1 shown in Figure 11 , in which the female half-mould 206 is spaced apart from the male half-mould 207. The movable central part 209 is arranged in the forward position PA in which the contact surface 12 is flush with a forming surface 218 of the base 213. The latter surface delimits the base 213 in its upper portion around the hole 214.

[0158] When the movable central part 209 is in the forward position PA, between the contact surface 12 of the movable central part 209 and the forming surface 218 of the base 213 a slit is defined, due to the difference in shape between the movable central part 209 and the hole 213.

[0159] The sectors 19 are in the enlarged configuration C1 .

[0160] A dose 2 of mouldable material is released between the female half-mould 206 and the male half-mould 207 by a conveying element not illustrated. If the dose 2 is made with a synthetic polymeric material, the dose 2 may be conveyed towards the moulding unit 201 by the conveying element, after it has been separated from a continuous extrudate coming out of an extruder. If, in contrast, the dose 2 is made with a natural fibre-based material, it may be cut from a web of starting material or obtained by compacting a powdered material.

[0161] The dose 2 is positioned on the female half-mould 206 in such a way that its central portion 30 is resting on the movable central part 209 and its peripheral portion 31 is resting on the base 213, in particular on the forming surface 218 of the base 213 which surrounds the hole 214. At this moment the dose 2 is spaced apart from the sectors 19.

[0162] Then, as shown in Figure 12, the sectors 19 are moved towards the moulding axis Z and brought into the forming configuration C2. The sectors 19 are not yet in contact with the dose 2 and at this stage they act as containment elements, which laterally contain the dose 2, preventing it from being positioned in a position that is too far off centre relative to the moulding axis Z.

[0163] A half-mould selected from the female half-mould 206 or the male halfmould 207 is now moved towards the other half-mould selected from the male half-mould 207 or the female half-mould 206. In the example illustrated, the female half-mould 206 is moved towards the male half-mould 207, for example by shifting the female half-mould 206 vertically upwards. The effect of this relative movement is that the locking sleeve 36 penetrates between the sectors 209, whose shaping surface 21 acts as a guide for the locking sleeve 36.

[0164] In this way, the dose 2 makes contact with the locking sleeve 36, in particular with its locking surface 37. In this way, the dose 2 is locked between the base 213 and the locking sleeve 36. That happens in a locking configuration Q2, of the type shown in Figure 13, in which the peripheral portion 31 of the dose 2 is locked between the locking surface 37 of the locking sleeve 36 and the forming surface 218 of the base 213. Locking the dose 2 between the locking sleeve 36 and the female halfmould 206 prevents lateral displacement of the dose 2, which guarantees good centring of the dose 2 in the moulding unit 201 .

[0165] Continuing to move the female half-mould 206 towards the male half-mould 207, the locking sleeve 36 is pushed upwards by the female half-mould 206. Consequently, the punch 222, which in the example illustrated is arranged in a fixed position along the moulding axis Z, starts to project from the locking sleeve 36. Simultaneously, the movable central part 209 moves backward towards the retracted position PR, and the dose 2 adopts a concave shape, as shown in Figure 14, in which the mouldable material has not yet reached the definitive shape, thickness or degree of compaction.

[0166] Figure 15 shows a final forming configuration Q4, in which the movable central part 209 has reached the retracted position PR, the sectors 19 are in the forming configuration C2 and the punch 222 is arranged in the projecting position PS. In this configuration, between the female half-mould 206 and the male half-mould 207 an object 3 is formed which, as previously mentioned, has the shape of a capsule, of the type used to contain a powdered material from which an extractable substance can be extracted, for example coffee. The capsule comprises a transversal wall 5, which is shaped between the movable central part 209 and the end forming surface

[0167] 23 of the punch 222. The capsule also comprises a lateral wall 4, having a frustoconical shape, which is shaped between the lateral forming surface

[0168] 24 of the punch 222 and the shaping lateral surface 38 of the hole 214. The capsule also has a flange 39, which is shaped between the forming surface 218 of the base 213, the locking surface 37 of the locking sleeve 36 and the shaping surface 21 of the sectors 19.

[0169] After the capsule has remained in the moulding unit 201 , arranged in the final forming configuration Q4, for a period of time sufficient to set its shape, the capsule is extracted from the moulding unit 201 and a new forming cycle can be started. In the embodiment shown in Figures 1 1 to 15, the peripheral portion 31 of the dose 2 is locked between the locking sleeve 36 and the half-mould facing the locking sleeve 36, due to a relative movement parallelly to the moulding direction D between the locking sleeve 36 and the half-mould facing the locking sleeve 36.

[0170] Furthermore, when the locking configuration Q2 has been reached, i.e. at the end of the locking step, the peripheral portion 31 of the dose 2 has not yet been compressed to its the final degree of compaction. The peripheral portion 31 continues to be compressed even after a further portion of the dose 2, which is adjacent to the peripheral portion 31 , starts to be shaped to form the lateral wall 204 of the object 3. This is clearly visible by comparing Figure 13 and Figure 15, which shows that the thickness of the peripheral portion 31 of the dose decreases even after the locking configuration Q2 has been reached.

[0171] In conclusion, the embodiments of the moulding unit shown in Figures 1 to 15 have the common feature that the dose of mouldable material is locked between a movable part and a half-mould facing the movable part before the dose has been completely formed. That happens by bringing the movable part and the half-mould facing it into contact with the dose, on opposite sides of the dose, in such a way that the dose is gripped between the movable part and the half-mould facing it. In this way, unwanted displacement of the dose during the forming step is avoided.

[0172] In an embodiment not illustrated, the sectors 19 of any of the moulding units shown in Figures 1 to 15 may be absent.

[0173] In the examples illustrated, a single movable part 9, 109, 209 was shown. In an embodiment not illustrated, there may be multiple movable parts, for example positioned coaxially one inside another, movable relative to each other telescopically.

[0174] The movements of the movable parts 9, 109, 209 may be passive, that is to say, made possible by elastic elements such as springs. It is also possible to provide driving elements which actively move the movable parts 9, 109, 209, for example hydraulic, pneumatic or other types of driving elements.

[0175] In addition to the functions described above, the movable parts 9, 109, 209 may have other additional functions. For example, the movable parts 9, 109, 209 may help with extraction of the formed object from the mould, or calibration of the compression force applied on the dose, or other functions.

Claims

CLAIMS1 . Method comprising the steps of:- inserting a dose (2) made with a mouldable material between a female half-mould (6; 106; 206) and a male half-mould (7; 107; 207);- forming an object (3) by moving at least one half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) towards the other half-mould selected from the male half-mould (7; 107; 207) or the female half-mould (6; 106; 206) along a moulding direction (D), in order to press the dose (2) between the male halfmould (7; 107; 207) and the female half-mould (6; 106; 206); wherein a locking step is provided for locking a portion of the dose (2) between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207) before the end of the forming step, and wherein a half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) comprises a movable central part (9; 109; 209), which is displaceable between a forward position (PA) and a retracted position (PR), the movable central part (9; 109; 209) being in the forward position (PA) during the step of locking a portion of the dose (2), the movable central part (9; 109; 209) being in the retracted position (PR) at least at the end of the forming step, and wherein, during the locking step, said portion of the dose (2) is clamped between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207) without reaching a final degree of compaction, said portion of the dose (2) being compressed between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207) until reaching the final degree of compaction after a further portion of the dose (2) has been deformed, the further portion being adjacent to said portion of the dose (2).

2. Method according to claim 1 , wherein said object (3) is a concave object having a lateral wall (4) closed at an end thereof by a transversal wall (5),said further portion of the dose (2) being deformed during the forming step to obtain the lateral wall (4).

3. Method according to claim 1 or 2, wherein, after the locking step and during the forming step, the mouldable material is thinned in said portion of the dose (2) to reach the final degree of compaction.

4. Method according to any preceding claim, wherein said portion of the dose (2) is a peripheral portion (31 ) and wherein, in the locking step, the peripheral portion (31 ) is locked between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207), while a central portion (30) of the dose (2) is resting on the movable central part, (9: 109; 209) arranged in the forward position (PA).

5. Method according to claim 4, wherein the peripheral portion (31 ) of the dose (2) is locked between a locking sleeve (36) of the male half-mould (7; 107; 207) and a forming surface (218) of the female half-mould (6; 106; 206), the forming surface (218) being arranged outside the movable central part (9; 109; 209) and around the movable central part (9; 109; 209).

6. Method according to any one of claims 1 to 3, wherein said portion of the dose (2) is a central portion (30) which, in the locking step, is locked between the movable central part (9; 109; 209), arranged in the forward position (PA), and the half-mould facing the movable central part (9; 109; 209), selected from the male half-mould (7; 107; 207) or the female halfmould (6; 106; 206).

7. Method according to claim 6, wherein said further portion of the dose (2) is a peripheral portion (31 ) arranged outside the central portion (30) and wherein, in the locking step, the peripheral portion (31 ) of the dose (2) is leftfree.

8. Method comprising the steps of:- inserting a dose (2) made with a mouldable material between a female half-mould (6; 106; 206) and a male half-mould (7; 107; 207);- forming an object (3) by moving at least one half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) towards the other half-mould selected from the male half-mould (7; 107; 207) or the female half-mould (6; 106; 206) along a moulding direction (D), in order to press the dose (2) between the male halfmould (7; 107; 207) and the female half-mould (6; 106; 206); wherein a locking step is provided for locking a portion of the dose (2) between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207) before the end of the forming step, and wherein a half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) comprises a movable central part (9; 109; 209), which is displaceable between a forward position (PA) and a retracted position (PR), the movable central part (9; 109; 209) being in the forward position (PA) during the step of locking a portion of the dose (2), the movable central part (9; 109; 209) being in the retracted position (PR) at least at the end of the forming step, wherein the dose (2) has a central portion (30) and a peripheral portion (31 ) and wherein, in the locking step, the peripheral portion (31 ) of the dose (2) is left free whereas the central portion (30) of the dose (2) is locked between the movable central part (9; 109; 209), arranged in the forward position (PA), and the half-mould facing the movable central part (9; 109; 209), selected from the male half-mould (7; 107; 207) or the female half-mould (6; 106; 206).

9. Method according to claim 8, wherein, after the locking step and duringthe forming step, the mouldable material is thinned in said portion of the dose (2).

10. Method according to any one of claims 6 to 9, wherein the central portion (30) of the dose (2) is locked between the movable central part (9; 109; 209) which is included in the female half-mould (6; 106; 206) and a punch (22) which is included in the male half-mould (7; 107; 207).11 . Method according to any one of claims 6 to 9, wherein the central portion (30) of the dose (2) is locked between the movable central part (9; 109; 209) which is included in the male half-mould (7; 107; 207) and a transversal surface (10) which delimits a forming cavity (8) of the female half-mould (6; 106; 206) transversally to the moulding direction (D).

12. Method according to any preceding claim, wherein the movable central part (9; 109; 209) receives the dose (2) which rests on the movable central part (9; 109; 209) in the forward position (PA) during the step of inserting the dose (2) between the female half-mould (6; 106; 206) and the male halfmould (7; 107; 207).

13. Method according to any preceding claim, wherein the dose (2) is made with a non-extrudable material which contains fibres.

14. Method according to any preceding claim, wherein a half-mould selected from the female half-mould (6; 106; 206) or the male half-mould (7; 107; 207) comprises a plurality of sectors (19) which are movable transversally to the moulding direction (D) between an enlarged configuration (C1 ) and a forming configuration (C2), and wherein the sectors (19) are arranged in the enlarged configuration (C1 ) when the dose (2) is received between the female half-mould (6; 106; 206) and the male half-mould (7; 107; 207), andwherein the sectors (19) form at least one lateral portion of the object (3)in the forming configuration (C2).

15. Method according to claim 14, wherein the sectors (19) are delimited by a receiving surface (29) which receives the dose (2) that rests on the receiving surface (29) in the enlarged configuration (C1 ).

16. Method according to claim 14 or 15, wherein the female half-mould (6; 106; 206) comprises a base (13) having a hole (14) in which the movable central part (9; 109; 209) is housed, and wherein, in the forward position (PA), the movable central part (9; 109; 209) projects from the hole (14) and is interposed between the sectors (19).

17. Method according to claim 15, or according to claim 16, as appended to claim 15, wherein, in the forward position (PA), a contact surface (12) which delimits the movable central part (9; 109; 209) transversally to the moulding direction (D) is flush with the receiving surface (29) of the sectors (19).

18. Method according to any one of claims 1 to 15, wherein the female halfmould (6; 106; 206) comprises a base (213) having a hole (214) in which the movable central part (9; 109; 209) is housed and wherein, in the forward position (PA), a contact surface (12) which delimits the movable central part (9; 109; 209) transversally to the moulding direction (D) is flush with a surface (218) of the base (213) which surrounds the hole (14).

19. Method according to any preceding claim, wherein the female halfmould (6; 106; 206) has a forming cavity (8) delimited by a transversal surface (10) transversally to the moulding direction (D), and wherein, during the forming step, a compensating element (25) included in the male halfmould (7; 107; 207) is positioned at a distance from the transversal surface(10), said distance depending on the mass of the dose (2), so that the object (3) has a dimension (H), measured along the moulding direction (D), which is greater the greater the mass of the dose (2) is.

20. Method according to claim 19, as appended to claim 14, wherein the compensating element (25) has a tubular body (26) delimited by a forming end (27) which is interposed between a male forming element (22; 122) of the male half-mould (7; 107; 207) and the sectors (19), during the forming step.21 . Method according to claim 1 , wherein the dose (2) has a central portion (30) and a peripheral portion (31 ), and wherein the peripheral portion (31 ) is deformed to obtain the object (3) after the central portion (30) has already been at least partly compressed to form a transversal wall (5) of the object (3).

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