Method for producing vulcanizing mould for tyres for vehicle wheels

Abstract

A method for producing a vulcanisation mould for a tyre for vehicle wheels, said vulcanisation mould comprising a plurality of sectors, where each sector comprises a moulding surface of a tread band portion of the tyre, for each sector, the method comprises:-bringing at least one surface portion of the moulding surface with a surface roughness starting from a digital model in which the surface roughness is defined by a predetermined algorithm by means of a numerical control device (110).

Description

Technical Field

[0001] This invention relates to a method for producing vulcanizing molds for tires used in vehicle wheels. Background Technology

[0002] Tires for vehicle wheels typically include a carcass structure shaped according to a basic toroidal configuration and comprising at least one carcass ply with axially opposite ends. These axially opposite ends engage with corresponding annular anchoring structures, each of which is typically formed by at least one basic circumferential annular insert (referred to as a "bead core"), on which at least one filler insert is typically applied, the filler insert being tapered radially away from the axis of rotation. The annular anchoring structures are located within a region commonly referred to as the "bead." The inner diameter of the bead substantially corresponds to the so-called "fitting diameter" of the tire on the corresponding mounting rim.

[0003] The tire also includes a crown structure comprising: at least one belt strip located radially outward relative to the carcass ply; and a tread belt located radially outward relative to the belt strip. Longitudinal and lateral cuts are typically formed on the tread belt, arranged to define a desired tread pattern. A so-called "underlayer," made of an elastomeric material with suitable properties, may be disposed between the tread belt and one or more belt strips to achieve a robust bond between the one or more belt strips and the tread belt.

[0004] The tire also includes a pair of so-called sidewalls made of an elastomeric material, which represent the tire's axial outer surface relative to a mid-surface perpendicular to the tire's axis of rotation. For example, the sidewalls represent the axial outer surface relative to the annular anchoring structure, one or more carcass plies, one or more belt strands, and possibly at least a portion of the tread band.

[0005] In a tubeless tire, at least one layer of elastomeric material (often referred to as a "liner") is provided in a radially inward location relative to the carcass ply, the elastomeric material layer having airtight properties and typically extending from one bead to another.

[0006] The tire production cycle includes the construction of a raw tire and subsequent molding and vulcanization processes. Specifically, the raw tire construction process includes building the carcass structure, building the crown structure, and forming and assembly steps, in which the carcass structure is given a toroidal shape by assembling it to the crown structure. The thus constructed raw tire is transferred to a molding and vulcanization line, where molding and vulcanization processes are performed to define the tire structure according to the desired geometry and tread pattern. For this purpose, the raw tire is arranged in a molding cavity defined within a vulcanization mold.

[0007] Typically, a vulcanizing mold includes a first sidewall, a second sidewall opposite the first sidewall, and a crown of a circumferential sector. The crown is configured to engage with the first and second sidewalls when the vulcanizing mold is closed for vulcanizing the green tire. The circumferential sector surrounds the molding cavity and typically has multiple shaped protrusions designed to create a series of grooves in the tread band appropriately arranged according to the desired tread pattern. Specifically, the surfaces of the circumferential sector are shaped in such a way that they collectively reproduce the negative mold of the desired tread pattern of the tire.

[0008] The term "elastomeric material" is used to refer to a composite comprising at least one elastomeric polymer and at least one reinforcing filler. Such composites may also include additives, such as crosslinking agents and / or plasticizers. Due to the presence of the crosslinking agent, such materials can be crosslinked by heating to form the final product.

[0009] The terms “axial,” “axially,” “radial,” “radial,” “circumferential,” and “circumferential” are used in reference to tires or the vulcanizing molds used in tire manufacturing processes.

[0010] In particular, the terms "axial" and "axially" are used to refer to a reference / quantity arranged / measured or extended in a direction substantially parallel to the axis of rotation of the tire or vulcanizing mold.

[0011] The terms “radial” and “radially” are used to refer to a reference / quantity arranged / measured or extended in a direction perpendicular to the axis of rotation of the tire or vulcanizing mold and located in a plane including such axis of rotation.

[0012] The terms “circumferential” and “circumferentially” are used to refer to a reference / quantity that is a circumferential arrangement / measurement or extension that develops along the axis of rotation around the tire or vulcanizing mold.

[0013] The term "raw tire" is used to refer to tires that have been produced through a building process but have not yet been molded and vulcanized.

[0014] The term "finished tire" is used to refer to a tire produced through a manufacturing process that includes constructing a raw tire and subsequently molding and vulcanizing the raw tire.

[0015] The term "tire" is used to refer to either finished tires or raw tires.

[0016] The terms “outer surface” and “inner surface” for the surfaces of molds used in the production process of tires, vulcanizing molds, or vulcanizing molds are intended to refer to the radially outer or radially inner surface relative to the axis of rotation of the tire or vulcanizing mold.

[0017] The term "tread groove" is intended to refer to a cut formed on the tread band that has a length greater than its width and a width less than or equal to 1.5 mm.

[0018] "Groove" is intended to refer to a cut formed on the tread band, the cut having a length greater than its width and a width greater than 1.5 mm.

[0019] "Block" is used to refer to the portion of the tread band defined by grooves rather than tread grooves. If a block is located on the outermost axial portion of the tread band, it is defined axially on one side by the outermost axial face of the tread band and on the other side by the grooves.

[0020] "Tread pattern" refers to a set of blocks, grooves, and tread grooves on the tread band.

[0021] The term "Berlin noise algorithm" is used to refer to an algorithm invented by Ken Perlin (see Perlin, Ken (July 1985), "An image synthesizer", ACM SIGGRAPH Computer Graphics, 19(97-8930): 287-296, dol: 10.1145 / 325165.325247), which is commonly used to digitally generate elements of random patterns, such as images and terrain.

[0022] Methods for producing vulcanizing molds suitable for forming a certain roughness on the surface of the tread strip of a tire are known in the art.

[0023] US 2010 / 0282387 describes a vulcanizing mold for tires. The mold has two or more segments whose forming surfaces collectively define the tire tread pattern. To ensure good grip during the initial running phase of the tire, certain areas of the forming surfaces of the mold segments are roughened, the roughness being adapted to form in corresponding areas of the tire tread band. This roughness is applied to the forming surfaces of the mold segments as a surface coating by a thermal spraying method.

[0024] EP 2799248 discloses a vulcanizing mold in which at least a portion of the molded surface of the tread strip has a predetermined surface roughness. The roughness of the molded surface of the tread strip is achieved by sandblasting and appropriately adjusting the sandblasting conditions (e.g., sandblasting pressure and speed).

[0025] EP 3117987 describes a process for producing mold segments whose surfaces form segments of the tread profile of a tire to be vulcanized and have a defined roughness. The process includes the following steps: manufacturing a master mold representing a male mold of the tread profile segments to be vulcanized; manufacturing a replica of the master mold to realize a silicone flexible part; manufacturing a replica of the silicone flexible part to realize a molded core; manufacturing a replica of the molded core to realize the mold segments; destroying the molded core and cleaning the mold segments. The desired roughness is achieved by applying defined-size particles to the surface of the silicone flexible part, the defined-size particles being firmly adhered to the silicone flexible part. The application of the particles is carried out by polymerization or adhesive bonding. Summary of the Invention

[0026] In the context of producing vulcanizing molds, which include the molded surface of a tire tread strip, at least a portion of the molded surface having a surface roughness, the applicant has recognized the need to provide an alternative production method that allows for optimization of such production in terms of industrial-scale applicability and the uniformity and repeatability of the results achieved for the molds and the molded and vulcanized tires.

[0027] The applicant has discovered that the aforementioned requirements can be met by a production method in which the surface roughness of a portion of the molded surface of the tire tread is manufactured starting from a digital model, wherein the surface roughness is defined by an algorithm in the digital model.

[0028] According to a first aspect of the invention, the present invention relates to a method for producing a vulcanizing mold for producing tires for vehicle wheels.

[0029] Preferably, the mold comprises multiple sector segments.

[0030] Preferably, each sector includes a molded surface of the tread band portion of the tire.

[0031] Preferably, for each sector, the method includes:

[0032] - Starting from a digital model, at least one surface portion of the molded surface is manufactured to have a surface roughness using a CNC machine, wherein the surface roughness is defined by a predetermined algorithm in the digital model.

[0033] According to the production method of the present invention, the surface roughness in a portion of the molded surface of the tire tread is then manufactured by a CNC machine operating based on a digital model, wherein the surface roughness is defined by an algorithm.

[0034] The applicant believes that, relative to known technologies, an alternative production method is provided that allows for the full automation of vulcanization mold production and optimizes it in terms of industrial-scale applicability and the uniformity and repeatability of the results achieved for the produced molds and molded and vulcanized tires.

[0035] The present invention may have at least one of the following preferred features in at least one of the above aspects.

[0036] Preferably, the multiple segments of the mold include circumferential segments that collectively define the molded surface of the entire tread strip.

[0037] Preferably, the molding surface of the entire tread strip is configured as a negative mold to reproduce the desired tread pattern of the tire.

[0038] Preferably, the predetermined algorithm is the Berlin noise algorithm.

[0039] Preferably, for each sector segment, a master model for manufacturing the sector segment is defined, the master model including the outer surface of the female mold representing the molding surface.

[0040] Preferably, the master model is made of resin.

[0041] Preferably, for each sector, silicone resin is cast on the outer surface of the model to create a silicone resin mold of the master model, the silicone resin mold including an inner surface representing the male mold of the molding surface.

[0042] Preferably, for each sector, plaster casting is performed on the inner surface of the silicone resin mold to create a plaster mold, the plaster mold including the outer surface of the female mold representing the molding surface.

[0043] Preferably, for each segment, metal casting is performed on the outer surface of the plaster mold to create a metal mold, the metal mold including the inner surface of the molded surface constituting the mold segment.

[0044] Preferably, the metal mold is made of aluminum.

[0045] In a preferred embodiment, for each sector, the surface roughness on at least one surface portion of the molded surface is achieved while the master model is being manufactured.

[0046] In this preferred embodiment, the outer surface of the model includes at least one surface portion having the surface roughness.

[0047] In this preferred embodiment, the master model is preferably manufactured by 3D printing, and the CNC equipment preferably includes a 3D printer for manufacturing the master model.

[0048] The 3D printer is preferably controlled by the digital model to form the surface roughness as defined by the predetermined algorithm on at least a portion of the outer surface of the model.

[0049] Alternatively, for each sector, a master model can preferably be manufactured by the CNC equipment, which performs material removal or laser engraving on a suitable starting material block (more preferably resin) and is controlled by the digital model to form the surface roughness as defined by the predetermined algorithm on at least one portion of the outer surface of the model.

[0050] In an alternative embodiment, the surface roughness on at least one surface portion of the molded surface is achieved during the fabrication of the plaster mold.

[0051] In this alternative embodiment, for each sector, the surface roughness is preferably achieved by applying material removal technology to the plaster mold using the CNC equipment starting from the digital model, in which the surface roughness is defined by the predetermined algorithm.

[0052] In another alternative embodiment, the surface roughness on at least one surface portion of the molded surface is achieved while manufacturing the metal mold.

[0053] In this alternative embodiment, for each sector, the surface roughness is achieved by applying material removal technology or laser engraving technology to the metal mold using the CNC equipment starting from the digital model, wherein the surface roughness is defined by the predetermined algorithm in the digital model.

[0054] Preferably, for each sector segment, it is specified that the plaster mold is removed from the metal mold to achieve a mold sector segment having the molded surface.

[0055] Preferably, for at least one sector, the outer surface of the model includes a plurality of first protrusions.

[0056] In one embodiment, the plurality of first protrusions are made of steel.

[0057] Preferably, for the at least one sector, manufacturing a silicone mold includes forming a plurality of grooves at the plurality of first protrusions in the inner surface of the silicone mold.

[0058] Preferably, for the at least one sector, a plurality of second protrusions are inserted into the interior of the plurality of grooves formed in the inner surface of the silicone molding.

[0059] Preferably, the plurality of second protrusions are made of steel, more preferably of sintered steel.

[0060] Preferably, the plurality of second protrusions are intended to form corresponding tread grooves in the tread band portion of the tire.

[0061] Preferably, for the at least one sector, after inserting the plurality of second protrusions into the interior of the plurality of grooves, plaster casting is performed on the inner surface of the silicone molding.

[0062] Preferably, for the at least one sector, manufacturing a plaster mold includes encapsulating a plurality of second protrusions in the outer surface of the plaster mold.

[0063] Preferably, for the at least one sector, manufacturing the metal mold includes encapsulating a plurality of second protrusions in the inner surface of the metal mold.

[0064] Preferably, for the at least one sector, the plaster mold is removed from the metal mold by leaving a plurality of second protrusions enclosed in the inner surface of the metal mold.

[0065] Preferably, the plurality of second protrusions encapsulated in the inner surface of the metal mold are intended to be used to form corresponding fine grooves in the tread band portion of the tire. Attached Figure Description

[0066] Further features and advantages of the invention will become clearer from the following detailed description of some exemplary embodiments of the invention, provided by way of non-limiting example only with reference to the accompanying drawings, wherein:

[0067] - Figure 1 A block diagram of a method for producing vulcanizing molds according to the present invention is shown;

[0068] - Figure 2 An example of a master model produced according to the production method of the present invention is shown;

[0069] - Figure 3 yes Figure 2 A magnified view of the details of the main model;

[0070] - Figure 4 Examples of the first and second grids that can be used to implement the Berlin noise algorithm are shown;

[0071] - Figure 5 It shows Figure 4 The details include defining a "gradient vector" and a "distance vector" for a point in the first grid. Detailed Implementation

[0072] Figure 1 A block diagram illustrating an embodiment of a vulcanizing mold for producing tires for vehicle wheels is shown, the vulcanizing mold comprising a plurality of segments, wherein each segment comprises a molded surface of a tread band portion of the tire.

[0073] Tires for vehicle wheels are typically manufactured through a production cycle that defines the manufacturing process of the raw tire and subsequent molding and vulcanization processes. According to known techniques, the construction process of a raw tire includes building the carcass structure, building the crown structure, and forming and assembly stages, in which the toroidal construction of the carcass structure is performed by assembling the carcass structure to the crown structure. The raw tire thus constructed undergoes molding and vulcanization processes adapted to define the tire's structure according to desired geometry and tread pattern. For this purpose, the raw tire is arranged within a molding cavity defined inside a vulcanization mold (not shown).

[0074] Typically, a vulcanizing mold includes a first sidewall, a second sidewall opposite the first sidewall, and a crown of circumferential sector segments. When the vulcanizing mold is closed for vulcanizing a green tire, the crown of the circumferential sector segment is configured to engage with both the first and second sidewalls. The circumferential sector segments surround the molding cavity and typically have multiple forming protrusions designed to form a series of grooves on the tread band, the grooves being appropriately arranged according to a desired tread pattern. In particular, these circumferential sector segments have molding surfaces shaped in such a way that they collectively replicate a negative mold of the desired tread pattern of the tire.

[0075] According to the present invention, the production method, starting from a digital model for each specified circumferential sector, manufactures at least one surface portion of the molded surface with a surface roughness by means of a CNC device 110, wherein the surface roughness is defined by a predetermined algorithm in the digital model.

[0076] To simplify the illustration, in Figure 1 The numerical control equipment 110 is shown in a completely schematic manner.

[0077] like Figure 1 As illustrated in the diagram, the predetermined algorithm can be stored in a dedicated memory 112 associated with the CNC device 110.

[0078] Preferably, the predetermined algorithm is the Berlin noise algorithm.

[0079] The Berlin noise algorithm allows for the digital generation of surface roughness with random patterns, in which a gradual transition between values ​​of points that are close to each other in the pattern is typically specified.

[0080] like Figure 4As illustrated, the implementation of the Berlin noise algorithm specifies the definition of a first and second grid of n dimensions that are superimposed. For simplicity, Figure 4 The two-dimensional case with n=2 is shown, where the first grid is represented by the smallest point and the second grid by the largest point, and both grids are squares. However, the case of rectangular grids is not excluded. Figure 4 In the diagram, parameter L represents the total length of an edge of the second grid (which also corresponds to the length of an edge of the first grid), parameter I represents the distance between two first nearest neighbors (i.e., two consecutive nearest neighbors) in the second grid, and parameter δ represents the distance between two first nearest neighbors (i.e., two consecutive nearest neighbors) in the first grid.

[0081] like Figure 5 As shown in more detail below, at each point of the second grid, a fixed random "gradient vector" G is generated, which has n dimensions and whose components have values ​​equal to 0, -1, or 1. For simplicity of illustration, Figure 5 Only four two-dimensional vectors G1, G2, G3, and G4 are shown.

[0082] For each point in the first grid (e.g.) Figure 5 (Illustrated using universal coordinates (m, n)), and also provides 2 n A "distance vector" is defined as follows: the distance vector connects the point with coordinates (m, n) in the first grid to the vertex of the cell containing the point with coordinates (m, n) in the second grid. n One point. At Figure 5 In the two-dimensional (i.e., n=2) case shown, four distance vectors D1, D2, D3 and D4 are defined. These four distance vectors connect the point with coordinates (m, n) in the first grid to the four points in the second grid that form the vertex of the cell to which the point with coordinates (m, n) belongs.

[0083] The Berlin noise algorithm calculates the 2-1 difference between the gradient vectors (G1, G2, G3, G4 in this example) and the corresponding distance vectors (D1, D2, D3, D4 in this example). n Scalar products (in this example, n=2, 2) n =4), and interpolate the resulting scalar product using a fadefunction to provide a value for each point in the first grid in the output.

[0084] The higher the density of the second grid, the richer the level of detail in the pattern generated by the Berlin noise algorithm.

[0085] Different rough surfaces can be achieved by changing the parameters L, I, and δ.

[0086] Preferably, a three-dimensional gradient vector and a two-dimensional grid (n=2) are used, so that the third component of the distance vector is always equal to 0.

[0087] For each sector, at box 101, specify the manufacturing master model 20 (e.g. Figure 2 As exemplarily shown), the master model constitutes a replica of the sector and includes an outer model surface 21, which represents the negative mold of the molding surface of the sector (and also the positive mold of the corresponding surface portion of the tire tread).

[0088] The main model 20 can be made of resin, for example.

[0089] In a preferred embodiment, the master model 20 is manufactured by 3D printing.

[0090] In an alternative embodiment, the master model 20 can be manufactured by performing material removal or laser engraving techniques on a suitable starting material block (e.g., resin).

[0091] like Figure 2 As schematically shown, the outer surface 21 of the model includes a set of blocks 23 and grooves 24, which are adapted to define the desired tread pattern of the corresponding tread strip portion of the tire to be printed.

[0092] Preferably, for at least one sector, the outer surface 21 of the model includes a plurality of first protrusions 22 (in Figure 3 It is most clearly visible in the magnified view.

[0093] The first protrusion 22 can be manufactured on the outer surface 21 of the model during the 3D printing of the main model 20 or while the main model is being manufactured using one of the aforementioned material removal or laser engraving techniques.

[0094] Alternatively, a special slot may be manufactured on the outer surface 21 of the model, into which the first protrusion 22 is inserted after the main model 20 is manufactured. In the latter case, the first protrusion 22 is preferably made of steel.

[0095] For each sector, at box 102, it is specified that silicone resin is cast on the outer surface 21 of the model to create a silicone resin mold (not shown) of the master model 20, the silicone resin mold including the inner surface of the male mold (and also the female mold representing the outer surface 21 of the model) representing the molding surface.

[0096] The silicone mold thus created represents the negative mold imprint of the main model 20. In other words, the inner surface of the silicone mold represents a negative mold replica of the outer surface of the main model.

[0097] For the at least one sector, wherein the plurality of first protrusions 22 are formed on the outer surface 21 of the model at the frame 101, a plurality of grooves are formed on the inner surface of the silicone resin mold at the plurality of first protrusions 22 while the silicone resin mold is being manufactured at the frame 102.

[0098] In this case, the production method specifies that a plurality of second protrusions (not shown) are inserted into the interior of the plurality of grooves formed in the inner surface of the silicone molding at block 102.

[0099] These multiple second protrusions are intended to form corresponding tread grooves in the corresponding tread strip portions of the green tire to be molded and vulcanized.

[0100] The second protrusion can be made of steel, for example.

[0101] At box 103, after the plurality of second protrusions are inserted into the interior of the plurality of grooves, it is specified that for each sector, plaster casting is performed on the inner surface of the silicone mold to create a plaster mold (not shown), the plaster mold including the outer surface of the female mold representing the molding surface.

[0102] The plaster mold thus created has an outer surface that represents a negative mold replica of the inner surface of the silicone mold.

[0103] During the fabrication of the plaster mold, multiple second protrusions remain encapsulated within the outer surface of the plaster mold.

[0104] At box 104, for each sector, it is then specified that metal casting is performed on the outer surface of the plaster mold to create a metal mold (not shown), which includes an inner surface that forms the molded surface of the mold sector.

[0105] The inner surface of the metal mold thus produced is a negative mold replica of the outer surface of the plaster mold.

[0106] Preferably, the metal mold is made of aluminum.

[0107] During the manufacturing of the metal mold, multiple second protrusions remain encapsulated within the inner surface of the metal mold.

[0108] At box 105, for each sector, it is specified that the plaster mold be removed from the metal mold to obtain a mold sector having the molded surface.

[0109] Plaster mold removal can be performed using a special tool (not shown) designed for crushing and removing plaster, followed by a subsequent cleaning and finishing stage.

[0110] The plaster mold is removed from the metal mold by leaving multiple second protrusions enclosed in the inner surface of the metal mold.

[0111] The second protrusion encapsulated in the inner surface of the metal mold is intended to form corresponding tread grooves in the tread strip portion of the tire to be printed.

[0112] According to the present invention, the surface roughness on at least one surface portion of the molded surface is achieved when the master model 20 is manufactured at frame 101 (first preferred variant), when a plaster mold is manufactured at frame 103 (second variant), or when a metal mold is manufactured at frame 104 (third variant).

[0113] In particular, in the first preferred variant, the aforementioned surface roughness is achieved at box 101 for each sector, while the main model 20 is manufactured by forming the surface roughness on the outer surface 21 of the model.

[0114] In an embodiment where the master model 20 is manufactured by 3D printing, the numerical control equipment 110 includes a 3D printer for manufacturing the master model 20, the 3D printer being controlled by the digital model to form the aforementioned surface roughness as defined by the predetermined algorithm on the outer surface 21 of the model.

[0115] Alternatively, in an embodiment where the master model 20 is manufactured by applying one of the material removal or laser engraving techniques, the CNC equipment 110 is configured to implement one of the techniques and is controlled by the digital model to form the aforementioned surface roughness as defined by the predetermined algorithm on the outer surface 21 of the model.

[0116] In the second alternative variant, the aforementioned surface roughness is achieved when creating a plaster mold at block 103.

[0117] In this second variation, for each sector, the surface roughness is achieved by a CNC device 110 configured to perform material removal technology on a plaster mold starting from the digital model, in which the surface roughness is defined by the predetermined algorithm.

[0118] In the third alternative variant, the aforementioned surface roughness is achieved when manufacturing the metal mold at block 104.

[0119] In this third variation, for each sector, the surface roughness is achieved by a CNC device 110 configured to perform material removal or laser engraving on a metal mold that has been produced and had plaster marks removed, starting from the digital model, in which the surface roughness is defined by the predetermined algorithm.

[0120] According to the production method of the invention, the surface roughness of the molding surface of the sector of the vulcanizing mold is manufactured by a CNC device 110 in one stage of the mold production process. The CNC device operates based on a digital model in which the surface roughness is defined by an algorithm. This advantageously allows for full automation of the vulcanizing mold production process, making it suitable for industrial scale and ensuring uniformity and repeatability of the results achieved for the produced molds and the molded and vulcanized tires.

Claims

1. A method for producing a vulcanizing mold for tires used as vehicle wheels, the vulcanizing mold comprising a plurality of segments, wherein, Each sector includes a molded surface of the tread band portion of the tire, and for each sector, the method includes: - Starting from a digital model, at least one surface portion of the molded surface is manufactured to have a surface roughness by a numerical control device (110), wherein the surface roughness is defined by a predetermined algorithm in the digital model.

2. The production method according to claim 1, wherein, The predetermined algorithm is the Berlin noise algorithm.

3. The production method according to claim 1 or 2, for each sector segment, the production method includes manufacturing a master model (20) of the sector segment, the master model including a model outer surface (21) of a female mold representing the molding surface.

4. The production method according to claim 3, for each sector, the production method includes casting silicone resin on the outer surface (21) of the model to manufacture a silicone resin mold of the master model, the silicone resin mold including the inner surface of the male mold representing the molding surface.

5. The production method according to claim 4, wherein for each sector, the production method includes casting plaster on the inner surface of the silicone mold to produce a plaster mold, the plaster mold including the outer surface of a female mold representing the molding surface.

6. The production method according to claim 5, wherein for each sector, the production method includes casting metal on the outer surface of the plaster mold to manufacture a metal mold, the metal mold including an inner surface of the molded surface of the sector constituting the mold.

7. The method according to claim 6, wherein, For each sector, the surface roughness on at least one surface portion of the molded surface is achieved while manufacturing the master model (20) or the plaster mold or the metal mold.

8. The method according to claim 7, wherein, For each sector, when the surface roughness is achieved while manufacturing the master model (20), the outer surface (21) of the model includes at least one surface portion having the surface roughness.

9. The method according to claim 8, wherein, The master model (20) is manufactured by 3D printing, and the numerical control device (110) includes a 3D printer controlled by the digital model to form the surface roughness as defined by the predetermined algorithm on at least one portion of the outer surface (21) of the model.

10. The method according to claim 8, wherein, For each sector, the master model (20) is manufactured by the CNC equipment (110), which performs material removal or laser engraving on a suitable starting material block and is controlled by the digital model to form the surface roughness as defined by the predetermined algorithm on at least one portion of the outer surface (21) of the model.

11. The method according to claim 7, wherein, For each sector, when the surface roughness is achieved while the plaster mold is being manufactured, the surface roughness is achieved by performing a material removal technique on the plaster mold by the CNC equipment (110) starting from the digital model, in which the surface roughness is defined by the predetermined algorithm.

12. The method according to claim 7, wherein, For each sector, when the surface roughness is achieved while manufacturing the metal mold, the surface roughness is achieved by performing material removal technology or laser engraving technology on the metal mold by the CNC equipment (110) starting from the digital model, in which the surface roughness is defined by the predetermined algorithm.

13. The method according to any one of claims 6 to 12, wherein for each segment, the method includes removing the plaster mold from the metal mold to achieve a molded segment having the molded surface.

14. The method according to any one of claims 3 to 13, wherein, For at least one sector, the outer surface (21) of the model includes a plurality of first protrusions (22).

15. The method according to claims 4 and 14, wherein, For the at least one sector, manufacturing the silicone mold includes forming a plurality of grooves in the inner surface of the silicone mold at the plurality of first protrusions (22).

16. The method of claim 15, wherein for the at least one sector, the method includes inserting a plurality of second protrusions into the interior of the plurality of grooves formed in the inner surface of the silicone mold.

17. The method according to claims 5 and 16, wherein, For the at least one sector, after inserting the plurality of second protrusions into the interior of the plurality of grooves, plaster casting is performed on the inner surface of the silicone mold.

18. The method according to claim 17, wherein, For the at least one sector, manufacturing the plaster mold includes encapsulating the plurality of second protrusions in the outer surface of the plaster mold.

19. The method according to claims 6 and 18, wherein, For the at least one sector, manufacturing the metal mold includes encapsulating the plurality of second protrusions in the inner surface of the metal mold.

20. The method according to claims 13 and 19, wherein, For the at least one sector, the plaster mold is removed from the metal mold by keeping the plurality of second protrusions enclosed in the inner surface of the metal mold.

21. The method according to any one of claims 16 to 20, wherein, The plurality of second protrusions are intended to form corresponding tread grooves in the tread band portion of the tire.

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