OF THREE-DIMENSIONAL PRINTING TO A WORK PLAN

DESCRIPTION

The present invention relates to a method and to a kit for anchoring items obtained by means of three-dimensional printing to a work surface. In particular, the present invention relates to a method and a kit for improving the adhesion of an item to a work surface, during its production by means of three-dimensional printing and, subsequently, storing it.

Therefore, the invention relates to the field of additive manufacturing, or more simply of 3D printing, or three-dimensional printing. “Three-dimensional printing” is meant as a manufacturing process of three-dimensional objects by means of an additive manufacturing method starting from a digital 3D model, obtained by means of a CAD modelling system.

As is known in the field, after a 3D model has been produced, it is subjected to a processing process using specific software programs that perform slicing of the geometry. In other words, these programs extract a sequence of successive cross-sections of the 3D model based on which the layers that together will form the object to be fabricated will be reproduced. Each cross-section corresponds to a layer of the 3D object.

There are different 3D printing technologies, which differ from one another in the method used to print the layers. The present invention concerns in particular the method known as FDM® (Fused Deposition Modeling) or also as FFF (Fused Filament Fabrication). It is based on the use of an extrusion head, or printing head, which is provided with a dispenser nozzle from which a molten polymer is delivered. This polymer is deposited in layers, based on the predetermined 3D model, so as to progressively form the item of the desired shape.

The present invention also relates to a printing method of similar type to the one described above, i.e., the 3D LDM (Liquid Deposition Modeling) method. In this method, the material, generally cold and in semi-fluid form, is loaded into a tank and pushed out through the nozzle by means of a piston, so as to be deposited in an orderly fashion according to a predetermined 3D model and thereby fabricate the item of the desired shape. Usually, this method is used with inert materials such as clay, concrete or resins, which are less subject to contraction phenomena during cooling compared to thermoplastic materials.

Usually, 3D printing uses 3-axis movement systems which extrude the material by means of the nozzle and deposit it so that it is coplanar to the work surface of the printer.

Prior art 3D printers have the problem of adhesion of the object to be produced to work surface. In other words, the first of the aforesaid layers, which is deposited on the work surface of the printer, might not adhere well or at all to this surface causing the production of defective items or interruption of the printing process. Moreover, also in cases in which the first layer initially adheres to this surface, it tends to separate therefrom subsequently, due to cooling of the material and hence its contraction, causing the same problems.

Many attempts have been made to solve these problems.

The method currently most widely used is heating a metal work surface by means electric resistors and applying chemical solvents and/or adhesives to this metal surface to increase adhesion of the first printing layer. Alternatively, a glass work surface coupled to a metal work surface is used, so as to increase the planarity of the base onto which the object is printed, and chemical solvents and/or adhesives are then applied to this glass surface. However, these methods are only effective in applications that use low melt thermoplastic materials. These materials have poor mechanical properties and are therefore rarely used for industrial applications. Moreover, these materials are intrinsically very stable, and therefore are less subject to contraction phenomena during the printing process. Therefore, it can be deduced that these methods are somewhat ineffective. Furthermore, these methods consume large amounts of energy and therefore not suitable for application to large work surfaces, i.e., having a surface equal to or greater than approximately Im ² .

Another prior art method, aimed at increasing adhesion between the object to be printed and the work surface of the printer, provides for the forming of a layer of material, chemically compatible with the material of the item to be printed, on the upper surface of the work surface, i.e. where the object to be printed is formed. This layer of compatible material is fixed to the work surface by means of mechanical fixing systems, adhesive solutions and/or vacuum pressure systems capable of creating a vacuum between the work surface and the compatible layer. The first layer of material to be printed is fused completely to this intermediate layer of compatible material, guaranteeing a high level of adhesion, also in the case of thermoplastic materials with high melt temperatures. However, these methods have some problems. Firstly, the material of the object to be printed adheres so well to the intermediate layer that it is difficult to separate them subsequently. In other words, once printing has terminated, to remove the intermediate layer (fused to the printed object) the use of machinery specifically made for this purpose is required. This causes higher production costs and times, making these methods unsuitable for advanced industrial productions. Moreover, once again these methods are only applicable to work surfaces of small size.

A further prior art solution consists in the use of abrasive surfaces capable of increasing the friction with the first print layer. These abrasive surfaces can be of many types, such as an adhesive tape or a surface made of carbon fiber or another synthetic fiber material. However, this solution also has the aforesaid limit relating to the size of the work surface. In fact, they are not effective for large surfaces.

A further method for improving adhesion of the object to be printed provides for the use of a metal work surface provided with small holes, which is coupled to a second surface without holes, which closes the holes of the first surface, making them blind. It allows an increase in the contact surface between the work surface and the first print layer, but is not sufficient for large work surfaces. Moreover, these solutions have a problem linked to the difficulty of thoroughly cleaning the blind holes. If the surface were to be used for subsequent processes, using plastic materials that are incompatible with one another, the residues of the first material would prevent anchoring of the second material, making the presence of the holes futile, or worse. This problem is particularly critical in the case of use of technopolymers.

Furthermore, all the above-mentioned prior art solutions have a common problem: they can only be used with flat work surfaces. This is problematic for the printing of items with complex geometries and/or with bases that are not flat. Therefore, these items are currently produced with printing processes that require high investment costs.

Consequently, prior art 3D printing methods and systems are not able to meet the demands of the current market: an increasingly demanding market in terms of sizes and shapes of the object to be printed, and in terms of plastic materials with increasingly high performance and that are therefore difficult to process.

Based on these considerations, there is a clear need to provide a method and a kit for anchoring items obtained by means of three-dimensional printing to a work surface that allows the above-mentioned problems to be eliminated or minimized.

Consequently, the aim of the present invention is to provide a method and a kit that allow the adhesion of items to a work surface during the three-dimensional printing process to be improved and maintained.

In particular, within this aim, an object of the present invention is to provide a method and a kit capable of anchoring items, during their printing process, to a work surface, also when using high melt thermoplastic materials, technopolymers, high performance polymers and composite materials made of polymer matrices and fibers (short or long) of any type and composition.

Another object of the present invention is to provide a method and a kit capable of anchoring items to a work surface during the printing process thereof, which can also be applied to work surfaces (and consequently to items) of large size, without being expensive.

One more object of the present invention is to provide a method and a kit for anchoring three- dimensionally printed items to related work surfaces that allow easy removal of said items from the work surface once the printing process has terminated.

A further object of the present invention is to provide a method and a kit for three- dimensional printing capable of anchoring the object to be printed to a work surface even in the case of objects with an irregular, or complex, shape, and work surfaces that are not flat.

These objects are achieved by means of a method as claimed in claim 1 and by means of a kit as claimed in claim 6.

In particular, the aforesaid objects are achieved through a method for anchoring an item obtained by means of three-dimensional printing to a work surface comprising the steps of: a. providing a panel provided with an upper surface, a lower surface and a plurality of through holes passing from said upper surface to said lower surface, said panel forming the work surface; b. positioning and holding the panel in position; c. depositing a layer of anchoring material in fluid or semi-fluid state on the upper surface of the panel by means of a printing head; d. allowing said fluid or semi-fluid anchoring material to flow through the through holes of the panel; e. leaving said anchoring material to at least partially solidify so that it anchors to the panel; f. continuing with three-dimensional printing of the item by depositing on the layer of anchoring material, anchored to the upper surface of the panel, subsequent layers of printing material.

The combination of these steps makes the method of the invention applicable and effective also to obtain large items and with complex geometrical shapes, also with high melt thermoplastic materials, with technopolymers and composite materials, avoiding high energy consumption and high costs. Moreover, such method facilitates the step of removing the item from the work surface, i.e., from the panel, due to the fact that mechanical and not chemical anchoring is used, as better explained below.

Preferably, the through holes of the panel have a constant cross-section from the upper surface to the lower surface of the panel and the step d) provides for allowing the anchoring material to flow through the through holes of the panel at least until the anchoring material exits at the lower surface of the panel.

In this way, the material that exits from the hole of the panel expands forming a sort of rivet head, i.e., a protrusion or bulge that, by solidifying, acts as a mechanical anchor, preventing the material from passing back through the panel and separating therefrom.

In this case, to remove the item from the panel, once printing has terminated, it is sufficient to slide a blade or equivalent means between the panel and the printed item, or, even more simply, it is possible to eliminate the bulges (for example by rubbing them off) and eliminate the excess material (i.e. the material contained inside the holes before removing the item) simply by passing a blade or equivalent means over the first print layer of the item.

Alternatively, the through holes of the panel have an increasing cross-section from the upper surface to the lower surface of the panel and the step d) provides for allowing the anchoring material to flow through the through holes of the panel at least until the anchoring material reaches a depth suitable to guarantee anchoring thereof to the panel once it has (totally or partially) solidified. In fact, in this case the conformation of the hole prevents the solidified material from slipping out of the hole, forming a sort of rivet head inside the panel.

In this case, to remove the item from the panel it is sufficient to pass a spatula, blade or equivalent means between the panel and the printed item.

According to preferred embodiments of the invention, the step f) of three-dimensional printing of the item to be produced is implemented moving the printing head by means of a movement system with a degree of freedom greater than or equal to three. This makes it possible to obtain objects of complex shape.

Advantageously, the step c) provides for depositing a thermoplastic resin in fluid state on the upper surface of said panel. In fact, thermoplastic resins can be melted by means of heating and subjected to shear forces in the extruder without degradation.

The above-mentioned problems relating to the prior art are also solved by means of a kit for anchoring an item obtained by means of three-dimensional printing to a work surface comprising: a panel provided with an upper surface, a lower surface and a plurality of through holes passing from said upper surface to said lower surface, said panel forming the work surface; fixing means for fixing said panel; a printing head, suitable for depositing an anchoring material in fluid or semi-fluid state on the upper surface of the panel, by means of a dispenser nozzle.

The combination of the features of these elements makes it possible to obtain a kit, applicable to any 3D printer, for producing items of various shapes and sizes using thermoplastics of any type, composite materials and technopolymers in general. This kit is simple to produce and apply, as well as inexpensive, and provides a quick and inexpensive three-dimensional printing process. Moreover, the aforesaid kit allows quick removal of the item produced from the work panel.

Preferably, the panel is flat, but it could also have an irregular surface.

The through holes are, preferably, perpendicular to the upper surface and to the lower surface of the panel, so as to be simple to produce.

Advantageously, said through holes have a constant cross-section from the upper surface to the lower surface of the panel, for the same reason.

In accordance with preferred embodiments of the invention, the through holes have a cylindrical shape, but could be of any shape.

Alternatively, said through holes have an increasing cross-section from the upper surface to the lower surface of the panel. For example, they could be conformed - completely or only for a portion of their depth - in the shape of a truncated cone or truncated pyramid.

Preferably, the panel is in a material selected from: metal, metal alloy, natural resin, synthetic resin, glass, carbon, inorganic material; or in a combination of these materials.

Preferably, the printing head intended to deposit the anchoring material is the same head intended to print the item to be produced. In this case, the printing head is moved by a movement system with a degree of freedom greater than or equal to three. In this way it is possible to obtain objects of complex shape.

In the present context, “upper surface of the panel” is meant as the surface intended to contact the item to be printed, while “lower surface of the panel” is meant as the surface opposite the upper surface.

Moreover, material in “fluid state” is meant as a material capable of flowing as it has low viscosity. Likewise, a semi-fluid material indicates a material with an intermediate viscosity between that of low viscosity fluids and that of dense fluids.

Further features and advantages of the present invention will be more apparent from the following description of preferred, but not exclusive, embodiments of a method and of a kit for anchoring items obtained by means of three-dimensional printing to a work surface according to the invention, illustrated by way of example in the accompanying drawings, wherein:

Fig. 1 shows a perspective schematic view of a preferred embodiment of a panel and of a printing head of a kit according to the present invention, during a step of the method of the present invention;

Fig. 2 shows an enlarged cross-sectional detail of Fig. 1;

Fig. 3 shows a perspective schematic view of a panel and of respective fixing means of a kit according to a second embodiment of the present invention;

Fig. 4 shows a perspective schematic view of a panel and of respective fixing means of a kit according to a third embodiment of the present invention;

Fig. 5a shows a perspective view of a panel of the kit according to a fourth embodiment of the invention;

Fig. 5b shows a cross-sectional view of Fig. 5a;

Figs. 6 and 7 show partial perspective schematic views of two different embodiments of a three-dimensional printer comprising the kit of the present invention.

With reference to Figs. 1 to 7, a kit for anchoring items obtained by means of three- dimensional printing to a work surface is indicated as a whole with the reference numeral 1.

The kit 1 of the invention comprises a panel 2 provided with an upper surface 3, intended to contact the item to be produced and with a lower surface 4, opposite the upper surface 3. The panel 2 is also provided with a plurality of through holes 5 passing from said upper surface 3 to said lower surface 4. This panel 2 forms the work surface during the printing process, i.e., the first print layer, and therefore the subsequent layers will be deposited on this panel 2 to produce the desired object.

The panel 2 is preferably flat, i.e., its upper surface 3 and its lower surface 4 are both flat, as shown in the embodiments illustrated, but it could also be of any shape and/or cross-section and could comprise irregular surfaces. The thickness of the panel 2 depends on the specific use for which it is intended. It is preferably between 1 mm and 5 mm.

Said panel 2 is in a material selected from: metal, metal alloy, natural resin, synthetic resin, glass, carbon, inorganic material; or in a combination of these materials. In the preferred embodiments this panel is in metal or in metal alloy as these materials are easier to machine, have a high stiffness, resistance to impacts and deformations, as well as an increased thermal conduction capacity and hence capacity to rapidly cool of the protrusions 11, which will be discussed below.

In the embodiments illustrated, the through holes 5 are perpendicular to the upper surface 3 and to the lower surface 4 of the panel 2, i.e., the axis of the holes 5 is orthogonal to the panel 2, although this axis could also be oblique.

In the first embodiment of the invention, said through holes 5 have a constant cross-section from the upper surface 3 to the lower surface 4 of the panel 2 (see Fig. 2).

In particular, the through holes 5 preferably have a cylindrical shape. However, they could be of a different shape and have a cross-section of any shape, such as a circle, a square or other regular or irregular polygon. Alternatively, the through holes 5 have an increasing cross-section from the upper surface 3 to the lower surface 4 of the panel 2. This cross section can increase continually, relative to the depth of the hole 5, as in the case of truncated cone or truncated pyramid shaped holes 5, or discontinuously, or a combination of the two. The cross-section of the holes 5 can also increase only partially between the upper surface 3 and the lower surface 4, i.e. it can be increasing only at a portion of the depth of the hole 5, as in the fourth embodiment, visible above all in Fig. 5b. In this case, the longitudinal section of the holes 5 is rectangular shaped in proximity of the upper surface 3 and truncated cone shaped in proximity of the lower surface 4. In other words, the cross-section is constant in the first portion and increasing in the second.

It is also possible to provide holes 5 with sections of different shapes one to another.

In accordance with the present invention, the kit 1 also comprises fixing means of the panel 2, suitable to block it in position during the printing process. In particular, the fixing means are used to fix the panel 2 to a frame of a three-dimensional printer or to a floor.

Said fixing means could comprise tensioners 6 connected to a rigid frame 7, as in the case of the third embodiment, illustrated in Fig. 4, or bolts 8 or equivalent means, as in the second embodiment, visible in Fig. 3.

The tensioners 6 shown in Fig. 4 comprise springs anchored, at a first end, to the panel 2 and, at a second end, to the rigid frame 7, although these springs could be replaced by screw tensioners or equivalent means.

In both cases, besides blocking the panel 2 in position, the fixing means prevent said panel 2 from bending due to the weight force of the item being printed and/or due to the force generated by contraction of the material 12 during cooling, once deposited.

According to the present invention, the kit 1 also comprises a printing head 9, suitable for depositing an anchoring material 12 in fluid or semi-fluid state on said panel 2, by means of a dispenser nozzle 10. The diameter of this nozzle 10 is preferably equal to or greater than the diameter of the through holes 5 of the panel 2, so as to prevent material 12 from falling in an uncontrolled manner into the holes 5 and hence irregularities in the item produced that could compromise both the aesthetic and the technical features thereof. Alternatively, the diameter of the nozzle 10 could also be smaller than the diameter of the holes 5 within certain limits, easily recognizable to those skilled in the art.

In accordance with preferred embodiments, the printing head 9 with which the anchoring layer is deposited is the same printing head of the three-dimensional printer with which the item to be produced is printed. In this case, the printing head 9 is preferably moved by a movement system 13 with a degree of freedom greater than or equal to three. In particular, this movement system 13 comprises a 3-axis Cartesian frame, such as the one shown in Fig. 7 (in which the printing head 9 moves along two directions orthogonal to each other and the panel 2 moves along a third direction orthogonal to the first two), or, more preferably, a six-axis industrial robotic system, such as the one in Fig. 6. Using complex movement systems, such as this latter, it is possible to vary the spatial orientation of the printing head 9 with great freedom and therefore to fabricate objects with complex geometries and, in general, items with higher performance.

Preferably, the printing head 9 is supplied with a thermoplastic resin such as polyethylene, polypropylene, polyamide or polyester. In fact, as mentioned previously, thermoplastic resins are easily melted by means of thermal energy and are the most suitable to be extruded from a printing head 9.

In accordance with some embodiments, the anchoring material 12 is the same printing material used to print the desired item. This is the best solution in terms of costs and time, when the printing head 9 of the anchoring material 12 is the same used to print the item.

As visible in Figs. 6 and 7, a 3D printer comprises a kit 1 and a movement system 13 of the printing head 9.

In particular, in Fig. 6, the movement system 13 comprises an industrial robotic system with six rotation axes. In this figure, the rotations are illustrated with arrows, each indicated with a corresponding Roman numeral from I to VI.

Instead, in Fig. 7 the movement system 13 comprises a tower structure on which the printing head 9 is free to move along two orthogonal directions and the work surface along a direction orthogonal to the first two. However, a movement system 13 in which the printing head 9 moves along one direction and the work surface along two directions or a movement system 13 in which the printing head moves along three directions and the work surface is fixed or similar systems with three degrees of freedom could be provided.

A method for anchoring an item obtained by means of three-dimensional printing to a work surface according to the present invention shall now be described.

The method comprises, according to a first step a), providing a panel 2 provided with an upper surface 3, a lower surface 4 and a plurality of through holes 5 passing from said upper surface 3 to said lower surface 4. This panel 2 is intended to act as work surface during the three-dimensional printing process.

The next step b) of the method provides for positioning and holding the panel 2 in position, by means of suitable fixing means, such as those described previously. In this way, not only does the panel 2 not move during printing but also is not subject to deformation, as explained previously.

Subsequently, a step c) of depositing an anchoring material 12 in fluid or semi-fluid state, on the upper surface 3 of said panel 2 is carried out. This material 12 can be the same material that will form the item to be printed or a material compatible therewith. The step c) is implemented by means of a printing head 9, which can be the same head of the three- dimensional printer intended to print the item or a different head separate from the 3D printer. This printing head 9 is provided with a dispenser nozzle 10 preferably having a diameter equal to or greater than the diameter of the holes 5. This step c) is visible in Fig. 1.

As already mentioned, if the anchoring material 12 is the same material used to print the item, it is advantageous to use a single printing head 9 for anchoring and printing the item.

This is followed by a step d) which provides for allowing said fluid or semi-fluid anchoring material 12 to flow through the through holes 5 of the panel 2 (Fig. 2).

A step e) of leaving said anchoring material 12 to at least partially solidify so that it anchors to the panel 2 is then carried out. In fact, after moved away from the printing head 9, the anchoring material 12, dispensed and left to flow through the holes 5, is no longer subjected to the conditions inside said head 9 but to environmental conditions, so that it solidifies through cooling or evaporation, as shall be described below. In both cases, the partially solidified anchoring material 12 is no longer malleable, and having a different shape to the shape of the holes 5 and/or larger sizes than the holes 5, it can no longer pass through them and thus remains mechanically anchored to the panel 2.

In the presence of a panel 2 with holes 5 with a constant cross-section from the upper surface 3 to the lower surface 4, the step d) provides for allowing the anchoring material 12 to flow through the through holes 5 of the panel 2 at least until the material 12 exits at the lower surface 4 of the panel 2. In this case, the portion of material 12 that has exited, at least partially solidifying, forms protrusions 11 or bulges that act as rivet heads, preventing the material 12 from passing back through the holes 5 and exiting from the upper surface 3, as visible in Fig. 2. In this way, the material 12 is mechanically anchored to the panel 2, preventing separation of the item being formed from the work surface (the panel 2), even in the case of contraction of the material 12.

In presence of a panel 2 with holes 5 with an increasing cross-section from the upper surface 3 to the lower surface 4 of said panel 2, the step d) provides for allowing the anchoring material 12 to flow through the through holes 5 of the panel 2 at least until the anchoring material 12 reaches a depth suitable to guarantee anchoring thereof to the panel 2. In the case of truncated cone shaped holes 5, for example, the material 12 could be made to penetrate until reaching approximately half the depth of the hole 5. In fact, as explained previously, in this case the conformation of the hole 5 ensures that the protrusions 11 form inside the hole 5, preventing the at least partially solidified material 12 from being extracted by means of a tensile force applied thereto in the direction from the lower surface 4 toward the upper surface 3. This configuration is recommended in the case in which a very thick panel 12 is used, so as to limit the amount of material 12 used.

In the fourth embodiment, shown in Figs. 5a and 5b, the panel 2 is very thick. In this case, the illustration shows a material 12 allowed to flow beyond the lower surface 4 of the panel 2, although it would be possible for the material 12 to be allowed to flow only until it reaches a depth suitable to guarantee anchoring.

Moreover, in cases in which the panel 2 is very thick, it is not necessary to use external fixing means to said panel 2, as the weight of the panel 2 itself can be used to hold it in position and prevent it from bending.

According to the type of material 12 used, the flow rate of said material 12 dispensed by the head 9, and the speed of movement of said head 9 must be regulated, so as to ensure that the anchoring material 12 flows through the lower surface 4 of the panel, in the case of holes 5 with a constant cross-section, or reaches the desired depth, in the case of holes 5 with an increasing cross-section, and hence anchors to the panel 2, after at least partially solidifying. This flow rate is generally regulated by acting on two parameters: the diameter of the hole of the nozzle 10 and its temperature (on which the viscosity of the material 12 depends), as known to those skilled in the art.

In accordance with the present invention, the method further provides for a step f) of continuing with three-dimensional printing of the item deposited on the upper surface 3, covered with anchoring material 12, or better on the layer of material 12 anchored to the upper surface 3, subsequent layers of printing material. As mentioned, this can be the anchoring material 12 itself or a material compatible therewith. For example, if the printing material is a composite material, the anchoring material 12 could comprise the polymer used to produce the composite material, so as to obtain good adhesion between anchoring material 12 and printing material.

Preferably, this step f) of three-dimensional printing is implemented by moving said printing head 9 by means of a movement system 13 with a degree of freedom greater than or equal to three. Even more preferably, the degrees of freedom are six and these movement systems 13 comprise a six-axis robotic system, to allow items of complex shape to be obtained. According to preferred embodiments of the method of the invention, the step c) provides for depositing a thermoplastic resin in fluid state on the upper surface 3 of said panel 2, for the reasons explained above. This thermoplastic resin could comprise polyethylene, polypropylene, polyamides or polyesters. Alternatively, the step c) provides for depositing an inert material in semi-fluid state on the upper surface 3 of the panel 2. In particular, this inert material can comprise clay, concrete or resin, preferably of thermosetting type.

If the material 12 dispensed from the printing head 9 and deposited on the panel 2 is a thermoplastic resin, the step e) of at least partial solidification will take place by means of heat exchange with the environment. In other words, once the thermoplastic resin exits from the nozzle 10, it is no longer subjected to the temperature of the head 9, but to a lower temperature, and therefore it cools and solidifies.

Instead, if it is an inert material 12, the step e) of at least partial solidification will take place by evaporation. In fact, after being dispensed and allowed to flow through the holes 5, in contact with the external environment, the inert material 12 loses its liquid portion and solidifies.

After the printing step f) it is possible to provide a step g) of removal of the printed item from the panel 2. This step can take place by removing the protrusions 11, if they exit from the panel 2, or by sliding a blade or equivalent means between the panel 2 and the printed item. In both cases, this step is simple and can be implemented quickly without the aid of specific machinery.

In the case in which removal is implemented by eliminating the protrusions 11, it is possible to then eliminate the excess material 12 (i.e., the material contained inside the holes 5 before removing the item) from the item produced simply by passing a blade or equivalent means on the first printing layer of the item.

As can be seen from the description provided, with the technical solutions used for the method and the kit 1 for anchoring an item obtained by means of three-dimensional printing to a work surface according to the present invention the aims and objects set forth can be fully achieved.

In fact, both guarantee anchoring to the work surface during the three-dimensional printing of items in any technopolymer, high melt polymer or composite material, also of large sizes and/or complex shapes, with limited costs and avoiding problems of removal of the item from the work surface.

The method and the kit of the invention can be used in many industry sectors in which additive manufacturing technologies are used. They are very advantageous for finished and semi-finished products that require characteristics of light weight and strength, above all if they have complex geometries and large sizes and if they require to be produced in small batches that do not justify the investment to produce a mold or if a dedicated mold cannot be produced due to the specific shape. Moreover, they are very advantageous for items made of materials subject to high levels of contraction during printing - and which therefore do not maintain suitable dimensional stability - and for this reason cannot be produced by means of additive manufacturing. The sectors in which the present invention could be widely utilized are the nautical, aeronautical, automobile and mechanical sectors in general. The present invention could also be widely used in the architectural sector to produce large customized load-bearing structures.

The method and the kit 1 of the invention thus conceived are suitable for many possible variants, all falling within the scope of the present invention. For example, the materials used and the contingent sizes and shapes may be any according to requirements and to the state of the art.