WO2021220243A1

WO2021220243A1 - Machine for three-dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles

Info

Publication number: WO2021220243A1
Application number: PCT/IB2021/053635
Authority: WO
Inventors: Matteo COPPELLI
Original assignee: Signa Fiduciaria S.R.L.
Priority date: 2020-04-30
Filing date: 2021-04-30
Publication date: 2021-11-04
Also published as: IT202000009535A1

Abstract

The machine (1) for three-dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, comprises: - a basic frame (2); - a movement assembly (7) of a belt (11) comprising a portion defining a substantially horizontal worktop (6); - a bar element (8), above said worktop (6); - a plurality of delivery heads (9), secured to said bar element (8) and adapted to deliver a construction material on the worktop (6) according to a pre- established pattern during the movement of the worktop (6), to define a plurality of overlapping layers (S) of the construction material; - a mutual approaching and spacing assembly (10) of the worktop (6) and of the bar element (8), to approach/space at least one of either the worktop (6) or the bar element (8) with respect to the other.

Description

MACHINE FOR THREE-DIMENSIONAL PRINTING OF BELTS FOR CONTINUOUSLY OPERATING PRESSING PLANTS, FOR PRESSING CERAMIC POWDERS AND OBTAINING CERAMIC FLOOR AND WALL TILES

Technical Field

The present invention relates to a machine for three-dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles.

Background Art

In the ceramic industry for the production of slabs and tiles for wall and floor coverings, it is well known that continuously operating pressing plants are used in which ceramic powders, moving on a feeding plane, are pressed by means of a rotating belt.

An example of such a plant is shown in patent document EP2763845.

When the belt is provided with depressions and reliefs, it is possible to obtain pressed slabs with a material effect, i.e. not perfectly smooth but with depressions and reliefs that reproduce in the negative the depressions and reliefs of the belt.

Manufacturing belts with depressions and reliefs using traditional technologies (e.g. by molding inside dedicated dies) is particularly complex and expensive. For this reason, patent document EP3099478 is intended to fabricate belts for continuously operating pressing plants using a three-dimensional printing process.

In this regard, it should be noted that in recent years there has been a significant spread of technologies for three-dimensional printing of objects of various shapes and uses.

These are extremely innovative technologies, and still in the process of being perfected, which allow making, through additive manufacturing processes, objects with geometries that are difficult to obtain through traditional manufacturing processes.

Some examples of processes for three-dimensional printing used industrially are selective laser sintering, laser stereo-lithography and Polyjet® printing with photopolymer.

Selective laser sintering exploits the use of a laser to sinter thermoplastic, metallic or silica powders.

This type of procedure, in fact, involves the use of an appliance that, by means of special distribution systems, spreads the layers of powder on a worktop that progressively lowers, thus maintaining a constant distance from the source of laser emission, comprised in the appliance itself.

A technology of this kind allows the use of different types of materials, but has the drawback that the surface finish of the objects obtained is irregular and requires further processing steps in order to make it homogeneous.

Such technology is also affected by high installation and operating costs.

The laser stereo-lithography process, on the other hand, is based on polymerization of a liquid resin by means of a laser focused on the worktop through optical systems.

This technology is also affected by high installation and operating costs and cannot ensure accurate surface finishes.

The Polyjet® printing process, finally, involves the use of appliances provided with nozzles that deposit acrylic or elastomeric-based photopolymers on very thin layers.

In these appliances, a head delivering small droplets of the photopolymer, moves on a horizontal surface by means of a Cartesian axis system, such as the traditional inkjet printer plotters.

The appliance is also provided with a UV light-emitting element, which causes the polymerization of the photopolymers and is also mounted on the movable head.

This last type of three-dimensional printer, although less expensive than the previous examples, is however susceptible to further upgrading aimed at simplifying the structural complexity thereof.

The back and forth movement of the printing heads, for example, sometimes causes criticalities in terms of precision of the material delivery as well as a significant slowdown of the entire manufacturing process.

Description of the Invention

The main aim of the present invention is to devise a machine for three- dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, which enables the manufacture of fine articles in a practical, easy and functional manner.

A further object of the present invention is to devise a machine for three- dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, which has an extremely simple structural architecture and with a reduced number of components.

Another object of the present invention is to devise a machine for three- dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, which allows overcoming the aforementioned drawbacks of the prior art within a simple, rational, easy, effective to use and low cost solution.

The aforementioned objects are achieved by the present machine for three- dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, 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 machine for three-dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, illustrated by way of an indicative, yet non-limiting example, in the accompanying tables of drawings wherein:

Figure 1 is an axonometric view of the machine according to the invention; Figure 2 is a side view, on an enlarged scale, of a detail of the machine in Figure

1. Embodiments of the Invention

With particular reference to the aforementioned figures, reference numeral 1 globally indicates a machine for three-dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles.

The machine 1, in particular, is intended to work on a belt 11 for continuously operating pressing plants.

The belt 11 is closed on itself in a loop and comprises a portion that, as will be better discussed below, defines a substantially horizontal worktop 6.

The worktop 6 defines a print field C extending along a substantially horizontal direction.

The print field C, in actual facts, consists of a characteristic dimension of the worktop 6 and coincides with the width of the belt 11.

The machine 1 comprises at least one basic frame 2 for resting on the ground.

In particular, the basic frame 2 comprises a holding structure 22 that extends substantially vertically.

Conveniently and not necessarily, the holding structure 22 is mounted inside a cabinet structure 3, provided with a main opening 4, through which it is possible, for example, to access the internal components of the machine 1. Advantageously, the main opening 4 is closable by means of a closing/opening system, consisting, e.g., of leaves 5 or the like.

The holding structure 22 is spaced apart from the main opening 4 to define a machine compartment enclosed inside the cabinet structure 3.

The machine 1 also comprises: at least one movement assembly 7 associated with the basic frame 2 and adapted to move the belt 11 wrapped at least partly around at least two rollers 12, 13, 14. More particularly, the movement assembly 7 comprises at least one driving unit 15 of at least one of the rollers 12, 13, 14 and is adapted to move the belt 11 and the worktop 6 along at least one direction of movement D substantially horizontal and transverse to the print field C; at least one bar element 8, which is associated with the basic frame 2 above the worktop 6 and extends along a substantially horizontal direction and transverse to the direction of movement D; a plurality of delivery heads 9, secured to the bar element 8 in a fixed position covering the substantial entirety of the print field C and adapted to deliver at least one construction material on the worktop 6 according to a pre-established pattern during the movement of the worktop 6 along the direction of movement D, to define a plurality of overlapping layers S of the construction material; at least one mutual approaching and spacing assembly 10 of the worktop 6 and of the bar element 8, to approach/space at least one of either the worktop 6 or the bar element 8 with respect to the other.

The construction material used in the machine 1 is preferably a plastic material, but it cannot be ruled out that different materials (e.g. metals and composites filled with glass fibers or carbon) may be used. At least two of the rollers 12, 13, 14 are arranged on the same substantially horizontal lying plane, wherein: a first roller 12 is arranged downstream of the delivery heads 9 with respect to the forward direction V of the worktop 6 along the direction of movement D; and - a second roller 13 is arranged upstream of the delivery heads 9 with respect to the forward direction V of the worktop 6 along the direction of movement D.

Conveniently, but not necessarily, the machine 1 also comprises at least a third roller 14 arranged lower than the first roller 12 and the second roller 13. In actual facts, the three rollers 12, 13, 14 divide the belt 11 into: a first stretch 16, extending between the first roller 12 and the second roller 13; a second stretch 17, extending between the second roller 13 and the third roller 14; and a third stretch 18, extending between the first roller 12 and the second roller 13. The first stretch 16 is substantially horizontal and defines the actual worktop 6. The second stretch 17 and the third stretch 18, on the other hand, are inclined.

It should be noted that the rollers 12, 13, 14 have a central axis A, around which they rotate.

The central axis A of the rollers 12, 13, 14 is horizontal and oriented orthogonally to the direction of movement D.

The third roller 14 is associated with at least one tensioning device 19, which is adapted to tension the belt 11.

The tensioning device 19, in actual facts, comprises a support 20, which holds the third roller 14, and a thrust assembly 21, which pushes the third roller 14 away from the first roller 12 and the second roller 13.

In particular, the support 20 is movable in a vertical direction and the thrust assembly 21 is adapted to lower and raise the support 20 and the third roller 14. The driving unit 15, which allows the rollers 12, 13, 14 to be set in rotation, is associated e.g. with the first roller 12.

Thus, the first roller 12 is motorized, while the second roller 13 and the third roller 14 are driven in rotation by the movement of the belt 11.

The rollers 12, 13, 14 (particularly the first roller 12 and the second roller 13, but also the third roller 14 when provided) are mounted cantilevered from the basic frame 2.

In particular, the rollers 12, 13, 14 extend from the holding structure 22 towards the main opening 4 inside the machine compartment enclosed in the cabinet structure 3; the assembly of the belt 11 on the rollers 12, 13, 14, as well as its disassembly, can be easily carried out through the main opening 4, by simply sliding it on the rollers 12, 13, 14 or pulling it off the rollers 12, 13, 14 with a horizontal slide.

The mutual approaching and spacing assembly 10 is advantageously configured to raise and lower the bar element 8, while the worktop 6 remains at a predetermined height.

In this regard, the mutual approaching and spacing assembly 10 comprises a vertical guidance unit 23 along which the bar element 8 is mounted in a sliding manner, and means, not shown in detail in the figures, for moving the bar element 8 along the vertical guidance unit 23.

The machine 1 comprises at least one fixing lamp 24 (“pinning”) that: is associated with the basic frame 2 above the worktop 6; extends along a substantially horizontal direction which is transverse to said direction of movement D covering the substantial entirety of the print field C; is arranged downstream of the delivery heads 9 and upstream of the first roller 12 with respect to the forward direction V of the worktop 6 along the direction of movement D; and is adapted to project towards the belt 11 an electromagnetic radiation adapted to secure the construction material on the belt 11 and/or on an underlying layer S of the construction material.

The machine 1 also comprises at least one curing lamp 25 that: is associated with the basic frame 2 above the worktop 6; extends along a substantially horizontal and transverse direction to the direction of movement D covering the substantial entirety of the print field C; is arranged upstream of the delivery heads 9 and downstream of the second roller 13 with respect to the forward direction V of the worktop 6 along the direction of movement D; and is adapted to project towards the belt 11 an electromagnetic radiation adapted to make the construction material harden on the belt 11 and/or on an underlying layer S of the construction material.

Conveniently, at least one of either the fixing lamp 24 or the curing lamp 25 is an ultraviolet lamp, preferably both.

The operation of the machine 1 is as follows.

The belt 11 is loaded onto the machine 1 by lifting the support 20 and bringing the third roller 14 closer to the other two rollers 12, 13.

Once the belt 11 has been mounted around the rollers 12, 13, 14, the third roller 14 is lowered so as to tension the belt 11. At this point, the driving unit 15 sets the first roller 12 in rotation and also drives the second roller 13 and the third roller 14 in rotation by means of the belt 11.

The rollers 12, 13, 14 always rotate in the same direction of rotation and the first stretch 16 of the belt 11 always moves along the direction of movement D in the forward direction V which displaces the belt 11 from the second roller 13 towards the first roller 12; this is advantageous since it allows the construction material to be deposited continuously.

As the belt 11 moves forward, the delivery heads 9 deliver the construction material according to a predetermined pattern, thus obtaining a plurality of overlapping layers S on the belt 11 with depressions and reliefs where required. The fact that the delivery heads 9 extend over substantially the entire print field C means that the construction material can be delivered over the entire surface of the belt 11 without displacing the delivery heads 9 with horizontal movements, thus ensuring high precision and fast delivery.

By means of the forward movement of the belt 11, the construction material delivered from the delivery heads 9 is made to pass below the fixing lamp 24, which irradiates the construction material with an electromagnetic radiation having an intensity such that the construction material may be fixed on the belt and/or on an underlying layer S of the construction material.

In this regard, it should be noted that the fixing lamp 24 specifically used to carry out pinning is arranged immediately after the delivery heads 9 so as to gel and block the construction material in the position in which it has been delivered.

In actual facts, the fastening obtained by means of the fixing lamp 24 allows the last layer S of the delivered construction material to adhere to the belt 11 and/or to a layer S of previously delivered construction material, but without fully curing; this allows the construction material to settle on the belt 11 without the formation of cracks and fissures even when the belt 11 bends as it passes around the rollers 12, 13, 14.

After having completed the turn around the three rollers 12, 13, 14, the last layer S of the delivered construction material passes under the curing lamp 25, which irradiates the construction material with an electromagnetic radiation having an intensity such that the construction material is finally cured on the belt 11 and/or on an underlying layer S of the construction material, before coming again under the delivery heads 9.

As the layers S of construction material are delivered, the bar element 8 is lifted by the mutual approaching and spacing assembly 10, so as to keep the delivery heads 9 at a constant distance from the previously delivered layers S of construction material and achieve precise and optimal deposition. In actual facts, the manufactured article obtained by means of the machine 1 consists of the belt 11 and the layers S of construction material gradually applied thereon.

Such a manufactured article can be used in the ceramic industry for pressing ceramic powders and obtaining floor and wall tiles in continuously operating pressing plants.

In this regard, it is underlined that, in an extremely practical, easy and cheap manner, the machine 1 is able to make on the belt 11 the depressions and reliefs necessary to obtain the material effect on the ceramic slabs.

Claims

1) Machine for three-dimensional printing of belts for continuously operating pressing plants, for pressing ceramic powders and obtaining ceramic floor and wall tiles, comprising: at least one basic frame (2); at least one movement assembly (7) associated with said basic frame (2) and adapted to move a belt (11) closed on itself in a loop, wrapped at least partly around at least two rollers (12, 13, 14) and comprising a portion defining a substantially horizontal worktop (6), wherein: said worktop (6) defines a print field (C) extending along a substantially horizontal direction; said movement assembly (7) is adapted to move said belt (11) and said worktop (6) along at least one direction of movement (D) substantially horizontal and transverse to said print field (C); and said movement assembly (7) comprises at least one driving unit (15) of at least one of said rollers (12, 13, 14); at least one bar element (8), which is associated to said basic frame (2) above said rollers (12, 13, 14) and with said worktop (6) and extends along a substantially horizontal direction which is transverse to said direction of movement (D); a plurality of delivery heads (9), secured to said bar element (8) in a fixed position covering the substantial entirety of said print field (C) and adapted to deliver at least one construction material on said worktop (6) according to a pre-established pattern during the movement of said worktop (6) along said direction of movement (D), to define a plurality of overlapping layers

(5) of said construction material; at least one mutual approaching and spacing assembly (10) of said worktop

(6) and of said bar element (8), to approach/space at least one of either said worktop (6) or said bar element (8) with respect to the other.

2) Machine (1) according to claim 1, characterized by the fact that at least two of said rollers (12, 13, 14) are arranged on the same substantially horizontal lying plane, of which: a first roller (12) is arranged downstream of said delivery heads (9) with respect to the forward direction (V) of said worktop (6) along said direction of movement (D); and a second roller (13) is arranged upstream of said delivery heads (9) with respect to the forward direction (V) of said worktop (6) along said direction of movement (D).

3) Machine (1) according to claim 2, characterized by the fact that it comprises at least a third roller (14) arranged lower than said first roller (12) and said second roller (13).

4) Machine (1) according to claim 3, characterized by the fact that it comprises at least one tensioning device (19) of said belt (11) associated with said third roller (14).

5) Machine (1) according to one or more of the preceding claims, characterized by the fact that it comprises at least one fixing lamp (24) which: is associated with said basic frame (2) above said worktop (6); extends along a substantially horizontal direction which is transverse to said direction of movement (D) covering the substantial entirety of said print field (C); is arranged downstream of said delivery heads (9) and upstream of said first roller (12) with respect to the forward direction of said worktop (6) along said direction of movement (D); and is adapted to project towards said belt (11) an electromagnetic radiation adapted to secure said construction material on said belt (11) and/or on an underlying layer (S) of said construction material.

6) Machine (1) according to one or more of the preceding claims, characterized by the fact that it comprises at least one curing lamp (25) which: is associated with said basic frame (2) above said worktop (6); extends along a substantially horizontal and transverse direction to said direction of movement (D) covering the substantial entirety of said print field (C); is arranged upstream of said delivery heads (9) and downstream of said second roller (13) with respect to the forward direction (V) of said worktop (6) along said direction of movement (D); and is adapted to project towards said belt (11) an electromagnetic radiation adapted to make said construction material harden on said belt (11) and/or on an underlying layer (S) of said construction material.

7) Machine (1) according to one or more of the preceding claims, characterized by the fact that said basic frame (2) comprises a holding structure (22) extending substantially vertically. 8) Machine (1) according to claim 7, characterized by the fact that said holding structure (22) is mounted inside a cabinet structure (3), provided with a main opening (4).

9) Machine (1) according to claim 8, characterized by the fact that said main opening (4) is closable by means of a closing/opening system. 10) Machine (1) according to one or more of claims 8 and 9, characterized by the fact that said holding structure (22) is spaced apart from said main opening (4) to define a machine compartment enclosed inside said cabinet structure (3).

11) Machine (1) according to one or more of the preceding claims, characterized by the fact that said rollers (12, 13, 14) are mounted cantilevered from said basic frame (2).

12) Machine (1) according to claims 10 and 11, characterized by the fact that said rollers (12, 13, 14) extend from said holding structure (22) towards said main opening (4) inside said machine compartment enclosed in said cabinet structure (3).