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Title:
PROCESS FOR THE THREE-DIMENSIONAL PRINTING OF MANUFACTURED ARTICLES
Document Type and Number:
WIPO Patent Application WO/2021/224845
Kind Code:
A1
Abstract:
The process comprises the following phases: supply of one three-dimensional printing device (2) provided with one dispensing assembly (3) of one construction material (PI, P2, P3) in the form of drops (G); supply of a plurality of types of construction material (PI, P2, P3) comprising a first type of construction material (PI) and a second type of construction material (P2), wherein the second type of construction material (P2) is coloured; deposition of a plurality of superimposed layers (L) of drops (G) in one of the types of construction material (PI, P2, P3) on a work surface (8) to obtain one manufactured article (1) to obtain: one internal portion (12) of the article (1) in the first type of construction material (PI); and one coloured surface portion (13) of the article (1), external with respect to the internal portion (12), in the second type of construction material (P2).

Inventors:
VACCARI ANDREA (IT)
Application Number:
PCT/IB2021/053843
Publication Date:
November 11, 2021
Filing Date:
May 06, 2021
Export Citation:
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Assignee:
GRAF SYNERGY SRL (IT)
International Classes:
B29C64/112; B29C64/336; B33Y10/00; B33Y30/00; B33Y40/00
Domestic Patent References:
WO2018207096A12018-11-15
Foreign References:
US20200130259A12020-04-30
US20200047252A12020-02-13
US7104773B22006-09-12
Attorney, Agent or Firm:
LUPPI, Emanuele (IT)
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Claims:
CLAIMS

1) Process for three-dimensional printing of manufactured articles, characterized by the fact that it comprises at least the following phases: supply of at least one three-dimensional printing device (2) provided with at least one dispensing assembly (3) of at least one construction material (PI, P2, P3) in the form of drops (G); supply of a plurality of types of construction material (PI, P2, P3) comprising at least a first type of construction material (PI) and a second type of construction material (P2), wherein said second type of construction material (P2) is coloured; deposition of a plurality of superimposed layers (L) of drops (G) in at least one of said types of construction material (PI, P2, P3) on a work surface (8) to obtain at least one manufactured article (1), said deposition comprising a repetition of at least one phase of dispensing a plurality of drops (G) in one or more of said types of construction material (PI, P2, P3) to obtain: at least one internal portion (12) of said manufactured article (1) obtained in said first type of construction material (PI); and at least one coloured surface portion (13) of said manufactured article (1), external with respect to said internal portion (12), obtained in said second type of construction material (P2).

2) Process according to claim 1, characterized by the fact that said deposition is carried out so as to obtain at least one coating portion (14) of said manufactured article (1) obtained in a third type of construction material (P3) placed externally to said coloured surface portion (13).

3) Process according to one or more of the preceding claims, characterized by the fact that said deposition comprises at least one leveling phase of each of said layers (L), after said dispensing phase.

4) Process according to one or more of the preceding claims, characterized by the fact that said leveling is carried out by removing part of said construction material (PI, P2, P3).

5) Process according to one or more of the preceding claims, characterized by the fact that said types of construction material (PI, P2, P3) are selected from the list comprising: plastic material, metallic material, glassy material, woody material.

6) Process according to one or more of the preceding claims, characterized by the fact that said first type of construction material (PI) comprises PVC. 7) Process according to one or more of the preceding claims, characterized by the fact that said first type of construction material (PI) comprises a liquid solution of PVC in at least one solvent, said deposition comprising at least one evaporation phase of said solvent carried out after said dispensing phase.

8) Process according to one or more of the preceding claims, characterized by the fact that said second type of construction material (P2) is a coloured material.

9) Process according to one or more of the preceding claims, characterized by the fact that at least one of either said second type of construction material (P2) or said third type of construction material (P3) is a UV proof material. 10) Process according to one or more of the preceding claims, characterized by the fact that said manufactured article (1) is selected from the list comprising: a window/door, a window/door frame or a portion thereof.

11 ) Three-dimensional printing device (2) for the manufacturing of manufactured articles by means of the process according to one or more of the preceding claims, comprising at least one dispensing assembly (3) of at least one construction material in the form of drops (G), characterized by the fact that said dispensing assembly (3) is provided with a plurality of dispensing heads (4) each one adapted to dispense a different type of construction material (PI, P2, P3). 12) Three-dimensional printing device (2) according to claim 11, characterized by the fact that it comprises at least one leveling unit (15) adapted to remove part of said construction material (PI, P2, P3) deposited by means of said dispensing assembly (3) so as to make the surface of each of said layers (L) even.

Description:
PROCESS FOR THE THREE-DIMENSIONAL PRINTING OF MANUFACTURED ARTICLES Technical Field

The present invention relates to a process for three-dimensional printing of manufactured articles.

Background Art

In recent years, technologies for three-dimensional printing of manufactured articles of various shapes and intended uses have become increasingly popular. These are extremely innovative technologies that are still being upgraded and allow for the creation of manufactured articles by means of additive manufacturing processes.

In particular, the processes for three-dimensional printing of known type involve the use of a three-dimensional printing device adapted to dispense a construction material on a work surface.

A first type of three-dimensional printing devices is the so-called three- dimensional strand printers.

Three-dimensional strand printers employ a construction material that is at least partly melted and then extruded in the form of strands.

The strands are then arranged on the work surface to form a plurality of superimposed layers shaping the manufactured article.

The three-dimensional printing carried out by means of this first type of printing devices allows obtaining manufactured articles in a variety of construction materials.

The process for three-dimensional strand printing, however, has drawbacks mainly related to the fact that the resulting manufactured article has a rather rough surface finish.

In particular, the surface of the manufactured article has lines and streaks that are generated by the combination of strands when making the layers.

In order to obtain manufactured articles provided with a valuable aesthetic effect, it is necessary, therefore, to employ subsequent finishing operations aimed at smoothing and flattening the outer surface.

This implies a lengthening of times and, not least, the finishing operation may damage the aesthetic effect of the manufactured article, especially in the case in which this features a particularly elaborate conformation.

A further type of process is described by W02018/207096A1, wherein through the use of a second type of three-dimensional printing device, the construction material is delivered in the form of drops.

The drop printing process allows giving the manufactured article a better surface finish than strand printing.

In particular, after being dispensed on the work surface, the drops adhere more easily to each other and make the surface of the finished manufactured article more even.

Through this type of process it is possible to obtain manufactured articles provided with a valuable aesthetic effect, for example it allows easily making grooves and depressions that give an effect of the material type to the finished manufactured article.

The processes for three-dimensional printing of known type do have some drawbacks.

The processes for three-dimensional printing of known type, in fact, do not allow making manufactured articles with elaborate decorative effects.

In more detail, the manufactured articles obtained through the three-dimensional printing generally require subsequent decoration operations.

These operations are carried out, e.g., through the application of inks by means of digital printing or paints by means of special dispensers.

Still, the decoration operations may comprise the application of adhesive films already decorated on the surface of the manufactured article.

These solutions, however, are often inadequate with the result that the manufactured article is provided with simple decorative effects, imprecise and unstable to external stress, such as, e.g., atmospheric agents or cleaning products.

Description of the Invention

The main aim of the present invention is to devise a process for three- dimensional printing of manufactured articles that allows obtaining a manufactured article provided with a surface finish that is resistant to external stresses and is durable over time.

A further object of the present invention is to devise a process for three- dimensional printing of manufactured articles that allows making a manufactured article provided with elaborate and precise decorative effects. Another object of the present invention is to devise a process for three- dimensional printing of manufactured articles that allows overcoming the aforementioned drawbacks of the prior art within a simple, rational, easy, effective to use and low cost solution.

The objects set out above are achieved by the present process for three- dimensional printing of manufactured articles having the characteristics of claim

1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more evident from the description of a preferred, but not exclusive, embodiment of a process for three-dimensional printing of manufactured articles, illustrated by way of an indicative, yet non-limiting example in the accompanying tables of drawings wherein:

Figure 1 is a schematic representation of a manufactured article obtained by means of the process according to the invention;

Figure 2 is a schematic representation of a three-dimensional printing device intended to implement the process according to the invention;

Figures 3-5 represent phases of the process according to the invention. Embodiments of the Invention

With particular reference to such figures, reference numeral 1 globally indicates a manufactured article obtained by means of the process according to the invention.

The process according to the invention first comprises a supply of at least one three-dimensional printing device 2 provided with at least one dispensing assembly 3 of at least one construction material PI, P2, P3 in the form of drops

G.

It is easy to appreciate that the construction material PI, P2, P3 is provided with a degree of viscosity that allows the dispensing thereof in the form of drops G. As shown in Figure 2, the dispensing assembly 3 comprises at least one dispensing head 4 adapted to dispense the construction material PI, P2, P3.

The dispensing head 4 is shaped so as to dispense the drops G with a size between 5 and 20 pm.

Preferably, the dispensing head 4 dispenses the drops G with a size of 10 pm. The dispensing head 4 is movable to dispense the drops G in order to make the manufactured article 1 according to a predefined three-dimensional model.

In detail, the dispensing head 4 is movable in the space by means of a system of controlled axes.

The three-dimensional printing device 2 is also provided with at least one electronic processing and control unit 5.

The electronic processing and control unit 5 comprises at least one driving unit 6 operatively connected to the dispensing assembly 3 and configured to move the dispensing head 4 according to the predefined three-dimensional model.

The electronic processing and control unit 5 also comprises at least one memory unit 7 operatively connected to the driving unit 6 and configured to store the predefined three-dimensional model.

The process then comprises the following phases: supply of a plurality of types of construction material PI, P2, P3 comprising at least a first type of construction material PI and a second type of construction material P2, wherein the second type of construction material P2 is coloured; deposition of a plurality of superimposed layers L of drops G in at least one of the types of construction material PI, P2, P3 on a work surface 8 to obtain at least one manufactured article 1.

Substantially, the present process allows making the manufactured article 1 by dispensing drops G of the construction material PI, P2, P3.

In this way, the manufactured article 1 is provided with a fine surface finish that would not be obtainable by the three-dimensional printing processes of known type.

In fact, the drops G have small size and a degree of viscosity such that, after they have been deposited, they adhere to each other and join together making the final surface very even.

The work surface 8 is substantially horizontal and fixed, and the dispensing head 4 moves with respect thereto.

In an alternative embodiment of the present invention, the work surface 8 is movable in the space according to a system of controlled axes so as to allow the manufactured article 1 to be made according to the predefined three- dimensional model.

Further embodiments cannot however be ruled out wherein the work surface 8 operates in conjunction with the dispensing head 4 by moving in a coordinated manner in order to shape the manufactured article 1 extremely quickly.

The manufactured article 1 is selected from the list comprising: a window/door, a window/door frame or a portion thereof.

In the preferred embodiment, schematically shown in Figure 1, the manufactured article 1 is, e.g., a window frame.

It cannot however be ruled out that the present process may be used for the construction of a manufactured article 1 of different type.

The deposition phase allows making a plurality of walls 9, 10, 11 of the manufactured article 1.

Specifically, the walls 9, 10, 11 comprise: a basic wall 9 extending in a substantially horizontal plane; side walls 10 extending transversely with respect to the basic wall 9; and an upper wall 11 associated with the side walls 10, substantially opposite the basic wall 9.

Preferably, the side walls 10 extend vertically.

In the embodiment shown in the figures, the walls 9, 10, 11 of the manufactured article 1 are schematically shown as flat surfaces.

It is easy to understand, however, that in actual facts the walls 9, 10, 11 may have irregular shapes and feature recesses and protrusions with respect to an ideal vertical plane.

To this end, the process may also comprise a phase of distribution of a plurality of superimposed layers of a backing material, which is not shown in the figures. In contrast to the construction material, the backing material is dispensed on the work surface 8 in order to define a resting surface for the construction material PI, P2, P3 dispensed during the subsequent phases of the three-dimensional printing process.

At the end of the process, the backing material is intended to be removed from the manufactured article 1.

The backing material is of the type, e.g., of a friable or water-soluble material that can be easily removed as a result of the manufacturing process. Conveniently, the three-dimensional printing device 2 comprises at least one dispensing unit, not shown in detail in the figures, adapted to dispense the backing material.

The deposition phase may, in addition, be carried out in such a way as to give the manufactured article 1 a textured surface effect.

In more detail, the dispensing of the construction material PI, P2, P3 is carried out so that the superimposing of the layers L generates grooves and/or surface depressions on the walls 9, 10, 11 according to a predefined pattern.

In more detail, the predefined three-dimensional model is created so as to define a particular predefined pattern on the walls 9, 10, 11 of the manufactured article 1.

The creation of the layers L by dispensing the drops G, having significantly reduced size, allows the textured surface effect to be obtained in an extremely precise and elaborate manner.

As shown in Figure 5, the deposition phase comprises a repetition of at least one phase of dispensing of a plurality of drops G in one or more of the types of construction material PI, P2, P3 to obtain: at least one internal portion 12 of the manufactured article 1 obtained in the first type of construction material PI; and at least one coloured surface portion 13 of the manufactured article 1, external with respect to the internal portion 12, obtained in the second type of construction material P2.

The types of construction material PI, P2, P3 are selected from the list comprising plastic material, metallic material, glassy material, woody material. Advantageously, the dispensing assembly 3 is provided with a plurality of dispensing heads 4, each one adapted to dispense a different type of construction material PI, P2, P3 on the work surface 8.

The dispensing heads 4 are also movable according to their respective systems of controlled axis in order to simplify the movement thereof and the dispensing of the respective construction materials PI, P2, P3.

In more detail, the dispensing heads 4 are operated independently by the driving unit 6 so as to distribute the drops G into the different types of the construction material PI, P2, P3, one alongside the other.

Conveniently, the first type of construction material PI comprises PVC.

PVC is a thermoplastic polymer provided with high strength and high elasticity, lightweight, strong, insulating and provided with low gas permeability; it is generally the material selected for making window and door frames.

During the production of PVC, depending on the intended use and the characteristics required of the material, additives are added to the PVC, so that by varying the type and dose of these additives, it is possible to obtain a material with totally different characteristics.

In particular, the typical additives that are added to PVC during manufacture are stabilizers to protect it from thermal degradation and improve resistance to light and weathering, plasticizers to give the product flexibility and elasticity, lubricants to facilitate processing, pigments for colouring, etc.

Preferably, the first type of construction material PI comprises a solution of PVC in at least one solvent.

The solvent is of the type of an organic solvent.

Conveniently, the solvent may be a mixture of an organic solvent and water, in varying percentages. Preferably, the percentage of organic solvent is between 30% and 40%.

This solution reduces the emission of organic solvent into the environment, which can be harmful to operators and the environment itself.

The organic solvent is at least one of either a ketone or an ether.

Preferably, the organic solvent is at least one of either a cyclic ketone or a cyclic ether, e.g. cyclohexanone and tetrahydrofuran, which can be used individually or in a mixture with each other and which are found to be particularly suitable solvents for dissolving PVC, although the possibility of using other types of solvents cannot be ruled out.

The organic solvent contained in the solution also softens the underlying layers L of PVC, which improves the adhesion of the various layers L and makes the manufactured article 1 more durable and stable.

Conveniently, the deposition phase comprises at least one evaporation phase of the solvent carried out after dispensing.

The evaporation phase of the solvent can occur naturally or forcibly.

In particular, in the case of forced evaporation of the solvent, it is possible to provide an evaporator assembly associated with the dispensing assembly 3, e.g. a hot air blower, an infrared lamp or other heating element, or an aspirator, which makes it possible to accelerate the evaporation phase of the solvent so that it immediately follows the dispensing phase.

By doing so, it is possible to make a layer L of PVC without the need for additional solidification steps of the distributed material.

The second type of construction material P2 is a coloured material.

Through the use of a coloured material, it is possible to make a manufactured article 1 provided with particular aesthetic effects, freeing oneself from the need to carry out subsequent decoration operations.

For example, the coloured material is of the type of an ink.

The coloured material can be dispensed on the underlying layers L in order to resume the previously applied textured surface effect or according to a different predefined pattern, so as to give a further decorative effect to the manufactured article 1.

Conveniently, the deposition phase comprises dispensing of a plurality of drops G into a plurality of second types of the construction material P2 of different colours.

To this end, the dispensing assembly 3 comprises a plurality of dispensing heads 4 adapted to dispense second types of construction material P2 of different colours.

Also in this case, the creation of the layers L by dispensing of drops G, provided with significantly small dimensions, allows obtaining an extremely precise and elaborate decorative effect.

Advantageously, the deposition is carried out so as to obtain at least one coating portion 14 of the manufactured article 1 obtained in a third type of construction material P3 arranged externally to the coloured surface portion 13.

The coating portion 14 has the function of protecting the coloured surface portion 13 from degradation phenomena caused by atmospheric agents to which window and door frames are generally subjected.

Advantageously, the third type of construction material P3 is a UV proof material.

PVC, in fact, is a material sensitive to UV rays, which cause a partial deterioration of the polymer by releasing hydrochloric acid.

Hydrochloric acid in turn can cause degradation of the coloured material of which the coloured surface portion 13 is made up, thus leading to a change in the decorative effect.

The UV proof material shall be selected from the list comprising: acrylic polymers, fluorinated polymers, or the like.

Preferably, the UV proof material is polymethyl methacrylate.

In addition, the third type of construction material P3 is a mechanical stress resistant material and allows the coating portion 14 to protect the underlying layers from scratches or nicks.

Embodiments of the present process cannot however be ruled out wherein the coating portion 14 is not implemented and wherein the second type of construction material P2 is a UV proof material.

In other words, the coloured surface portion 13 is made of a coloured, UV proof material.

Similarly to the above, the second type of construction material P2 can also be a mechanical stress resistant material.

Conveniently, the deposition phase comprises at least one levelling phase of each of the layers L, after the dispensing phase.

In particular, during the dispensing phase, the drops G are arranged side by side so as to adhere to each other.

Then, the levelling phase has the function of making the surface of the layer L even.

As shown in Figure 4, levelling is carried out by removing part of the construction material PI, P2, P3.

Levelling may comprise a phase of recovery of the removed construction material PI, P2, P3 which can be used again for subsequent dispensing operations.

To this end, the three-dimensional printing device 2 comprises at least one levelling unit 15 adapted to remove part of the construction material PI, P2, P3 deposited by means of the dispensing assembly 3 so as to make the surface of each of the layers L even.

The levelling unit 15 comprises at least one smoothing element 16, such as a trowel, adapted to remove part of the construction material PI, P2, P3 to level the surface of the layer L.

The levelling unit 15 also comprises at least one removal element 17, of the type of, e.g., a roller, adapted to move away the construction material PI, P2, P3 previously removed by the smoothing element 16.

It cannot however be ruled out that the levelling unit 15 may be devoid of the smoothing element 16 and comprise only the removal element 17. According to such an embodiment, the removal element 17 is adapted to remove and at the same time moving away, part of the construction material PI, P2, P3 from the surface of the layer L.

The levelling unit 15 may also comprise at least one containment body 18, of the type of, e.g., a tank, associated with the removal element 17 and adapted to contain the removed construction material PI, P2, P3.

According to a further aspect, the present invention relates to a three- dimensional printing device 2 intended to implement the above-described process.

The three-dimensional printing device 2 comprises at least one dispensing assembly 3 of at least one construction material PI, P2, P3 in the form of drops G. According to the invention, the dispensing assembly 3 is provided with a plurality of dispensing heads 4, each adapted to dispense a different type of construction material PI, P2, P3 . It has in practice been ascertained that the described invention achieves the intended objects, and in particular the fact is emphasized that the process for three-dimensional printing of manufactured articles according to the invention allows obtaining a manufactured article provided with a surface finish that is resistant to external stresses and that is durable over time.

In addition, this process makes it possible to make a manufactured article provided with elaborate and precise decorative effects.