Shaping process

Abstract

A shaping process comprising: supplying a raw material (10) comprising at least 15% by mass of thermoplastic materials, in solid form, onto a support (12); heating the support (12) and the raw material (10) in a heating device (20), such as an oven, to a temperature equal to or greater than a threshold temperature; after heating, transferring the support (12) and the raw material (10) from the heating device (20) to a main press (40); compressing the raw material (10) in the main press (40), the main press (40) being thermally controlled at a temperature below the threshold temperature. Figure for the abstract: Fig. 1

Description

Title of the invention: Shaping method technical field

[0001] The present description relates to a shaping process, and more particularly to a process for shaping a raw material, for example granular, comprising at least 15% by mass of thermoplastic materials in solid form. Such a process can be implemented for shaping materials obtained from waste recycling. Previous technique

[0002] Among the processes for shaping raw materials, thermocompression processes, also called hot compression, are known, mentioned in the Applicant's patent application FR 3 078 353 Al which describes the introduction of a mold filled with chips into a press, the heating of the press and the mold in order to agglomerate the chips to form a block, and the cooling of the press and the mold.

[0003] Although this process is satisfactory, the press used for the compression stage undergoes numerous heating and cooling cycles. These cycles are energy-intensive. When the purpose of thermocompression is to recover value from used materials, such as waste, the significant energy used to heat and cool the press can substantially reduce the energy savings that would normally result from recycling existing materials compared to producing a new product.

[0004] There is therefore a need for a new type of shaping process. Description of the invention

[0005] To this end, the present description relates to a shaping process, comprising: - the supply of a raw material comprising at least 15% by mass of thermoplastic materials, in solid form, on a support; - heating the support and the raw material in a heating device, such as an oven, to a temperature greater than or equal to a threshold temperature; - after heating, the transfer of the support and raw material from the heating device to a main press; - the compression of the raw material in the main press, the main press being thermally regulated to a temperature below the threshold temperature.

[0006] The raw material can be obtained from recycling, in particular from household waste. The raw material may have undergone pretreatments such as sorting, shredding, grinding, granulation, etc. The raw material is supplied in solid form: the process is not a material formulation process, for example of plastics from liquid compounds, but rather a shaping of a pre-existing raw material in solid state.

[0007] Thanks to the fact that the raw material comprises at least 15% by mass of thermoplastic materials, the raw material can be shaped alone, without the addition of a binder or other matrix: indeed, the thermoplastic material, under the effect of heat in the heating device, ensures the bond between the other constituents of the raw material and allows, after compression, the formation of a single piece.

[0008] Plastic materials comprise one or more polymers.

[0009] The raw material is heated to a first temperature, which is greater than or equal to a threshold temperature. This first temperature can be measured directly in the raw material using sensors known per se. In another example, the heating device can be regulated to the first temperature, and the raw material is left in the heating device for a sufficiently long heating time to consider that the raw material has reached this first temperature.

[0010] After heating, the raw material and the support structure are transferred from the heating device to a main press. It follows that the heating device and the main press are independent of each other. In particular, temperature variations in the heating device have no significant thermal effect on the main press, and vice versa.

[0011] In the main press, the raw material is compressed while the main press is regulated to a second temperature, lower than the threshold temperature. For example, the second temperature may be a setpoint temperature of the main press, and may correspond to the temperature of a component of the main press configured to come into contact with the raw material in steady state.

[0012] Because the second temperature is below the threshold temperature, the compression of the raw material is carried out cold. This is referred to as cold thermocompression, meaning that the material has been preheated but the actual compression is performed cold.

[0013] The thermal regulation of the main press to a temperature below the threshold temperature can occur from the beginning of the compression of the raw material, or even throughout this compression. The main press is therefore thermally regulated, from the beginning of the compression or even throughout it, at said temperature. lower temperature.

[0014] Unlike conventional thermocompression processes, the heating is carried out outside the main press, thus avoiding the energy-intensive cycle of heating and then cooling the main press. Thanks to the dedicated heating device and the fact that the main press is thermally regulated to a temperature below the threshold temperature, the main press is heated little or not at all: essentially only the substrate and the plastic materials are heated. This results in significant energy savings and increased productivity.

[0015] In certain embodiments, the threshold temperature is such that the raw material could not, on its own, retain its shape during transfer between the heating device and the main press. The support then allows the raw material to be contained despite the temperature rise. The presence of a support enables the raw material to be moved, and thus ultimately heated and compressed in two different devices: one – the heating device – which is relatively hot, and the other – the main press – which is relatively cold. This separation of functions and the use of a support to transport the material allows for the aforementioned energy savings.

[0016] In some embodiments, the threshold temperature is greater than or equal to 130°C, preferably 150°C, and even more preferably 170°C.

[0017] For example, the first temperature may be greater than or equal to 130°C, preferably 150°C, and even more preferably 170°C. The first temperature may be less than or equal to 250°C, preferably 230°C, and even more preferably 200°C. These ranges for the first temperature allow for good softening of the thermoplastic materials to ensure consistent shaping during compression.

[0018] Furthermore, according to an example, the second temperature may be less than or equal to 50°C, preferably less than or equal to 30°C, preferably less than or equal to 20°C, preferably even less than or equal to 15°C.

[0019] More generally, the difference between the first temperature and the second temperature can be greater than or equal to 50°C, preferably 80°C, preferably even 100°C, preferably even 130°C. Therefore, during compression, rapid cooling occurs which prevents excessive deformation of the material (runs) and ensures a good appearance of the finished part.

[0020] In certain embodiments, the main press includes a punch configured to come into contact with the raw material or the support, the punch including thermal control means. For example, a setpoint temperature for these thermal control means, during the compression of the raw material, may be less than or equal to 50°C, preferably less than or equal to 30°C, preferably less than or equal to 20°C, preferably even less than or equal to 15°C.

[0021] In some embodiments, the raw material is supplied to the support in granular form. This allows for a more even distribution on the support. Furthermore, in the case of waste recovery, this allows for the reuse of a larger proportion of waste.

[0022] In some embodiments, compression aggregates the raw material in granular form to form a plate.

[0023] In other embodiments, the raw material is a single piece, for example a panel. The shaping process can then be configured to modify the shape of the panel, for example to give it a three-dimensional curved shape.

[0024] In certain embodiments, the support has a thickness less than the thickness of the raw material placed on the support. The thickness of the support refers to its smallest dimension; similarly, the thickness of the raw material placed on the support refers to the smallest dimension of the entire raw material once it is placed on the support. For example, the thickness of the raw material can be measured perpendicular to the support. Thanks to these arrangements, the support is relatively thin, which means that relatively little energy is required to heat it. The shaping process is therefore more energy-efficient, since most of the heating is supplied directly to the raw material. In addition, the thermal resistance of the support is reduced, which makes the heating of the raw material more homogeneous.

[0025] In some embodiments, the thickness of the support is less than or equal to 5 millimeters (mm), preferably 4 mm, preferably even more 3 mm.

[0026] In certain embodiments, the support is a mold comprising a base and side walls, and the main press includes a housing configured to receive the mold, the shape of the housing conforming to the side walls of the mold. Because the shape of the housing conforms to the side walls of the mold, the housing of the main press acts as a buffer for the mold walls, preventing them from deforming during compression. In other words, the compressive forces are absorbed not by the mold itself, but by the housing of the main press. This allows for a particularly thin mold and thus further reduces the energy required to heat the mold.

[0027] In some embodiments, the walls of the housing are thicker than the walls of the mold, for example at least twice as thick, or even at least five times as thick.

[0028] In some embodiments, at least one wall of the housing is retractable. This facilitates the insertion of the mold into the housing. The housing wall can be a wall designed to come against a lateral wall of the mold.

[0029] In certain embodiments, the mold cooperates with the main press to remain in its housing. This prevents the mold from snagging on other parts of the press; on the contrary, by remaining in the housing, which can be designed to facilitate the insertion and removal of the mold, the extraction of raw materials from the press is facilitated. The cooperation between the mold and the press can, in particular, be mechanical.

[0030] In some embodiments, the support comprises a sheet. For example, the raw material, if it retains sufficient cohesion despite the temperature increase so that it remains on the sheet despite softening, can simply be placed on a sheet, preferably a flexible one. Optionally, the raw material can be placed between two sheets. One or more such sheets are suitable for a wide variety of forming configurations in the press.

[0031] In some embodiments, the heating device is an oven configured to hold a plurality of substrates simultaneously, optionally on several levels. This increases the production rate and the energy efficiency of the oven. The oven allows for homogeneous and controlled heating of the substrate and the raw material.

[0032] In some embodiments, the oven includes heating means and forced convection means configured to homogenize the temperature within the oven, optionally by ensuring air movement from the oven walls towards the center of the oven. For example, the heating means may include an electric resistance system. The convection means may include a fan.

[0033] In some embodiments, the heating device comprises an inlet and an outlet, and a section of the heating device on the inlet side is thermally regulated differently from a section of the heating device on the outlet side. The heating device may also include conveying means between the inlet and the outlet. Thus, the raw material can be heated according to a more precise temperature program than simply maintaining a constant temperature.

[0034] Alternatively or in addition, in certain embodiments, the heating device includes a temperature sensor configured to measure a temperature by contact with the raw material. Such a sensor, comprising a probe immersed in a material, is known per se.

[0035] In some embodiments, the support is made of steel coated with a non-stick coating. In other embodiments, the support is made of aluminum.

[0036] In certain embodiments, the main press includes at least one gauge block to determine the thickness to which the raw material is compressed. The gauge block may be located between two parts of the main press that are movable relative to each other, forming a punch and a die. The gauge block may limit the movement of the movable parts towards each other, in order to better achieve the desired dimensions for the compressed raw material.

[0037] In some embodiments, the punch is made of aluminum. Aluminum has non-stick properties.

[0038] In some embodiments, the raw material comprises at least 18% by mass of thermoplastic materials, preferably at least 20%, preferably at least 25%, and preferably at least 30%. In some embodiments, the raw material comprises at least 80% by mass of thermoplastic materials, preferably at least 90% or even 95%.

[0039] In certain embodiments, the raw material is derived from the recycling of waste, particularly household waste such as hygiene product bottles (shampoo, shower gel, etc.) or pharmaceutical products, beverage cartons, industrial production waste, and any other waste comprising at least 15% by mass of thermoplastic materials. The raw material may be derived from the recycling of one or more types of waste. The raw material may be homogeneous or heterogeneous. Typically, granules or chips from the same type of waste have, on average, the same composition and are considered to form a homogeneous raw material, even if the waste in question comprises several materials.

[0040] In some embodiments, the plastics comprise at least one of the following materials: polyethylene (PE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), polystyrene (PS), polypropylene (PP), natural thermoplastic such as bio-based polyethylene (bio-PE derived for example from sugar cane), polycaprolactone (PCL), polylactic acid (PLA), polyhydroxyalkanoates (PHA), poly(butyl succinate) (PBS), or other starch-based polymers.

[0041] In certain embodiments, the process further comprises, during the transfer from the heating device to the main press, an intermediate compression step at a temperature above the threshold temperature in an intermediate press separate from the main press, for a shorter duration than the compression time in the main press. This intermediate hot thermocompression, also called "flash compression" because of its speed, improves the surface finish of the formed part and increases its scratch resistance. The intermediate press is separate from the main press to avoid energy-intensive heating / cooling cycles. In particular, the intermediate press can be maintained at a temperature above the threshold temperature.

[0042] The present disclosure also relates to a shaping installation, the installation comprising a support suitable for receiving raw material comprising at least 15% thermoplastic materials, in solid form, a heating device, such as an oven, configured to heat the support and the raw material to a temperature greater than or equal to a threshold temperature, and a main press configured to compress the raw material, the main press comprising thermal control means configured to thermally regulate the main press to a temperature lower than the threshold temperature of the heating device.

[0043] The installation can be configured for the implementation of the shaping process described above, and can have all or part of the characteristics detailed about said process. Brief description of the drawings

[0044] Other features and advantages of the subject matter of this presentation will become apparent from the following description of embodiments, given by way of non-limiting examples, with reference to the attached figures.

[0045] Fig. 1 is a diagram illustrating the main steps of a shaping process according to one embodiment.

[0046] Fig. 2 is a partial cross-sectional view of a main press and a support according to one embodiment, in plane II of Fig. 1. Detailed description

[0047] A shaping process according to an embodiment is described with reference to Figures 1 and 2. This process is intended to shape a solid raw material comprising at least 15% by mass of thermoplastic materials, in order to form a part. This raw material may be derived from consumer or industrial waste, which may have undergone preliminary processing such as sorting, cleaning, shredding, mixing, homogenization, etc. The raw material may comprise a single material or a mixture of different materials, as long as the mass proportion of thermoplastic materials remains greater than or equal to 15%.

[0048] In this embodiment, the raw material may be supplied in granular form, for example billets or chips, or more generally granules. The raw material may have granules of different shapes, sizes and / or colors, in order to give a marbled appearance to the part.

[0049] As illustrated in [Fig. 1], the raw material 10 is supplied on a support 12. For example, the granules can be deposited on the support 12 so as to form a layer. The thickness el of the layer can be uniform or not, depending on the part you want to create.

[0050] In this embodiment, the support 12 has a thickness e2 that is less than the thickness el of the raw material layer 10. The thickness e2 of the support may be constant or variable. The thickness e2 of the support 12 may be the smallest dimension of the support 12.

[0051] In this embodiment, in order to contain the granules, particularly laterally, the support 12 can be a mold comprising a base 14 and side walls 16. The side walls 16 project from the base 14, all in the same direction. The side walls 16 can define a closed contour.

[0052] The internal surfaces of the support 12, i.e. those intended to be in contact with the raw material 10, can be coated with a non-stick or release material so that once the part is formed, it can be easily removed from the support 12. This coating can also be configured to prevent adhesion between the raw material 10 and the support 12 despite the temperature and pressure applied, which will be described later.

[0053] Before or after being placed on the support 12, the raw material 10 can be preheated, for example to a temperature between 30°C and 100°C, in order to dry it. This makes the flow of the granules more fluid and makes the temperature rise of the raw material 10 more gradual.

[0054] The shaping process includes heating the support 12 and the raw material 10 in a heating device 20 to a first temperature TL. This first temperature Tl is greater than or equal to a threshold temperature T0. By heating the raw material 10 in this way, at least partial melting of the thermoplastic materials contained within the raw material 10 occurs, which allows these plastic materials to be deformed or, in the case of granules, ensures adhesion of the granules to each other to form a single piece. If necessary, heating to the first temperature Tl may also cause degassing of the raw material 10.

[0055] For example, the threshold temperature T0, or a fortiori the first temperature Tl, is greater than or equal to 130°C, preferably 150°C, and even more preferably 170°C.

[0056] In this case, the heating device 20 comprises or is an oven (hereinafter referred to as oven 20 for the sake of brevity, without loss of generality). The oven 20 comprises a closed enclosure 22, into which the support 12 can be inserted through at least one hatch, for example, a first hatch forming an inlet 24 and a second hatch forming an outlet 26. The inlet 24 and the outlet 26 can be provided on either side of the oven 20.

[0057] A section of the oven 20 on the inlet side 24 can be thermally regulated differently from a section of the heating device on the outlet side 26. By For example, the oven 20 can be hotter on the outlet side 26 than on the inlet side 24, in order to promote a gradual and homogeneous rise in temperature of the raw material 10 and to compensate for the fresh air intakes that occur when the hatch forming the outlet 26 is open, these air intakes being especially detrimental when the raw material 10 is hot.

[0058] At least one conveyor 28 may be provided to facilitate the transport of the support 12 from the inlet 24 to the outlet 26. For example, the conveyor 28 may be motorized. The conveyor 28 may operate continuously or intermittently, as supports 12 are inserted into and removed from the oven 20.

[0059] The oven 20 can be equipped with heating means of any type, for example an electric resistance heating system 30. Furthermore, convection means can be provided, in this case at least one fan 32, to homogenize the temperature within the oven. Depending on the orientation of the fans, the temperature can be homogenized by zone, so that the presence of convection means does not, in itself, preclude different temperature control on the inlet side 24 and the outlet side 26.

[0060] Optionally, the oven 20 may include a temperature sensor 34. According to one example, the temperature sensor 34 is configured to measure the temperature in the oven 20 by contact with the air in the oven 20. According to another example, the sensor 34 is configured to measure a temperature by contact with the raw material 10, typically via a probe.

[0061] The temperature inside the oven 20 can be determined so that, given a specified residence time in the oven 20, the raw material 10 reaches the first desired temperature Tl. To accelerate heating and increase productivity, the temperature of the oven 20 (particularly in the section on the outlet side 26) can be higher than the first temperature TL

[0062] As illustrated, the oven 20 can be configured to hold a plurality of supports 12 simultaneously. This can be achieved by appropriately sizing the oven 20. Alternatively or in addition, the oven 20 can be configured to hold supports on several levels. In this case, the oven 28 comprises several superimposed conveyors 28, each conveyor 28 defining a level.

[0063] Once the raw material 10 has reached the first temperature Tl, the support 12 and the raw material 10 it contains are removed from the oven 20 and transferred to a main press 40. Suitable transfer equipment may be provided, such as a lifting table.

[0064] The support 12 is placed in the main press 40 and the main press 40 is actuated to compress the raw material 10 between two rigid parts movable relative to each other, namely, for example, a punch 42 and a die 44. The Punch 42 and die 44 can move relative to each other under the action of one or more cylinders 46. In this case, punch 42 is mobile while die 44 is fixed, but the reverse configuration is also possible. The fact that the lower part, in this case die 44, is mobile, ensures greater stability of the movements within the press 40.

[0065] As previously stated, the main press is thermally regulated at a second temperature T2, lower than the threshold temperature T0. In this embodiment, the second temperature T2 is less than or equal to 20°C, and the temperature difference T1-T2 between the first temperature T1 and the second temperature T2 is greater than 130°C. The temperature T2 here refers to the steady-state temperature of a component of the main press configured to come into contact with the raw material 10, i.e., the punch 42 and / or the die 44. To this end, the punch 42 and / or the die 44 may include thermal regulation means 48 whose setpoint temperature during the compression of the raw material 10 is equal to the second temperature T2. In this case, the thermal regulation means 48 include a conduit 48a embedded in the punch 42 and / or in the die 44, this conduit 48a being traversed by a refrigerant fluid.As can be seen from Figures 1 and 2, the conduit 48a can meander through the punch 42 and / or the die 44.

[0066] The punch 42 can be configured to come into contact with the raw material 10, while the die 44 supports the holder 12. The punch 42 can be made of aluminum or aluminum alloy. Aluminum is a non-stick material with high thermal capacity, which allows it to quickly dissipate the heat stored in contact with the hot raw material 10 as it exits the oven 20.

[0067] As illustrated in [Fig.2], the main press 40 can include a housing 50 configured to receive the support 12. This housing 50 can be provided in the die 44. As illustrated, the shape of the housing 50 can fit the side walls 16 of the support 12: in other words, when the support 12 is inserted into the housing 50, the housing 50 comes against the side walls of the support 12 so as to prevent the support 12 from deforming under the action of the pressure imparted by the punch 42.

[0068] To hold the support 12 in the housing 50, the support 12 may be provided to cooperate with the main press 40. More specifically, the support 12 may cooperate mechanically with the housing 50 or with the die 44. In the example shown, the support 12 is provided with fins 18 projecting outwards from the support 12, i.e., towards the housing 50, and configured to engage in corresponding grooves 52 in the housing 50. The grooves 52 and fins 18 can block the translation of the support 12 relative to the housing 50 in the direction in which the parts of the main press 40 are movable relative to each other, which corresponds to the vertical direction on [Fig.2]. For example, the fins 18 can extend parallel to the raw material layer 10.

[0069] The support 12 can be inserted into the housing 50 by translation perpendicular to the plane of [Fig. 2], the fins 18 cooperating with the grooves 52 to form slides. In order to allow the insertion and removal of the support 12, at least one wall of the housing 50 can be retractable. In this case, in addition to the walls formed by the die 44 and illustrated in [Fig. 2], a wall of the housing 50 can be formed by a cross member 54 separate from the die 44 and movable relative to the die 44. The cross member 54 can be assembled to the die 44 once the support 12 is inserted into the housing 50, and retracted to remove the support 12 from the housing 50.

[0070] In the example illustrated in [Fig. 1], the cross member 54 is fixed in translation to the punch 42 and protrudes beyond the punch 42 in the direction of the die 44. Thus, when the punch 42 approaches the die 44 to compress the raw material 10, the cross member 54 approaches the die 44 a fortiori. The cross member 54 thus moves until it meets a wall of the support 12, which wall may be without a fin 18 as shown in the first vignette of [Fig. 1]. When the punch 42 then reaches the raw material 10, all the walls of the support 12 are supported by the walls of the housing 50 formed respectively by the die 44 and the cross member 54. When the punch 42 is then moved away from the raw material 10, the cross member 54 is also moved so as to open the housing 50 again. Thus, the movement of the cross member 54 is indexed to that of the punch 42, and its placement and removal are automatic.

[0071] Fig. 2 further shows that the main press 40 includes shims 56 forming a template to limit the penetration of the punch 42 into the support 12, and thus calibrate the thickness of the part resulting from the compression of the raw material 10. The shims 56 can be removable, in which case it is possible to provide several sets of shims corresponding to several manufacturing thicknesses.

[0072] In the main press 40, the compressed part is cooled. After demolding, the part can be subjected to one or more post-treatments, for example deburring, sanding, etc., or any desired machining.

[0073] Although the present description refers to specific embodiments, modifications may be made to these examples without departing from the general scope of the invention as defined by the claims.

[0074] For example, the shaping process is not only applicable to raw materials supplied in granular form, but to raw materials of any shape. For example, it is possible to supply a single piece on a support, with heating and cold compression intended to give this piece a different shape. Typically, it is possible to obtain a curved shape. starting from a flat panel.

[0075] The support 12 has been presented in the form of a mold, but it is not necessarily a mold. The support 12 can be a simple sheet serving as an intermediary for transferring the raw material 10 between the heating device 20 and the main press 40. As an example, the raw material can be placed between two flexible sheets. The shape to be imparted to the finished part is then defined by the punch 42 and the die 44, and not by the punch 42 and the support 12.

[0076] In addition to the steps described above, the shaping process may include, during the transfer from the heating device 20 to the main press 40, an intermediate compression step of the raw material 10 at a third temperature T3 higher than the threshold temperature T0 in an intermediate press separate from the main press, for a shorter duration than the compression time in the main press. The intermediate press may have all or some of the characteristics of the main press 40, but is separate from it in the sense that the support 12 and the raw material 10 must be moved between the intermediate press and the main press 40.In order to share certain mechanical means of applying pressure, the main press 40 and the intermediate press can form two separate stages of the same compression installation, but the main press 40 is kept relatively cold while the intermediate press is kept relatively hot.

[0077] Although the mechanical cooperation between the support 12 and the housing 50 has been described as an engagement of fins 18 of the support 12 with grooves 52 of the housing, it is possible to reverse these means: grooves may be provided on the support 12 while the housing 50 comprises fins. Furthermore, other cooperation systems are envisaged. For example, the support 12 may include eyelets, for instance, to allow the support 12 to be gripped by a robot. The main press 40 may include retractable fingers configured to engage with or retract from the eyelets. The eyelets may be provided as extensions of the side walls 16, so that the support 12 can be inserted into the housing 50 from above. In this embodiment, the housing 50 does not require a retractable wall.

[0078] Although the heating device 20 has been presented as an oven, other heating devices may be considered.

[0079] In addition to these variations, other variants are possible, and individual features of the different embodiments illustrated or mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Demands

1. A shaping process comprising: - supplying a raw material (10) comprising at least 15% by mass of thermoplastic materials, in solid and granular form, on a support (12); - heating the support (12) and the granular raw material (10) in a heating device (20), such as an oven, to a temperature greater than or equal to a threshold temperature, the heating device (20) comprising convection means (32); - after heating, transferring the support (12) and the raw material (10) from the heating device (20) to a main press (40); - compressing the raw material (10) in the main press (40), the main press (40) being thermally regulated at a temperature below the threshold temperature.

2. A shaping method according to claim 1, wherein the threshold temperature is greater than or equal to 130°C, preferably 150°C, preferably even more 170°C.

3. A shaping method according to claim 1 or 2, wherein the main press (40) comprises a punch (42) configured to come into contact with the raw material (10) or the support (12), the punch (42) comprising thermal control means (48) having a setpoint temperature during the compression of the raw material (10) less than or equal to 50°C, preferably less than or equal to 30°C, preferably less than or equal to 20°C, preferably still less than or equal to 15°C.

4. A shaping method according to any one of claims 1 to 3, further comprising, during the transfer of the heating device (20) to the main press (40), an intermediate compression step at a temperature above the threshold temperature in an intermediate press separate from the main press (40), for a period shorter than the duration of the compression in the main press (40).

5. A shaping method according to any one of claims 1 to 4, in which the support (12) has a thickness (e2) less than the thickness (el) of the raw material (10) disposed on the support (12).

6. A shaping method according to any one of claims 1 to 5, wherein the support (12) is a mold comprising a bottom (14) and side walls (16), and the main press (40) comprises a housing (50) configured to receive the mold, the shape of the housing (50) conforming to the side walls (16) of the mold.

7. A shaping method according to claim 6, wherein at least one wall (54) of the housing (50) is retractable.

8. Shaping method according to claim 6 or 7, wherein the mold cooperates with the main press (40) for its retention in the housing (50).

9. A shaping method according to any one of claims 1 to 8, wherein the heating device (20) is an oven configured to hold a plurality of supports (12) simultaneously, optionally on several levels.

10. A shaping method according to any one of claims 1 to 9, wherein the heating device (20) comprises an inlet (24) and an outlet (26), and a section of the heating device (20) on the inlet (24) side is thermally regulated differently from a section of the heating device (20) on the outlet (26) side, or wherein the heating device (20) comprises a temperature sensor (34) configured to measure a temperature by contact with the raw material (10).

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