Casting apparatus and casting method for manufacturing ceramic articles

Abstract

Casting method and apparatus (1) for manufacturing ceramic articles (2), the apparatus (1) comprising: - a mould (3) which, in turn, comprises: at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) mutually movable between a closed configuration, in which they are coupled to one another to define a casting cavity (5) and an open configuration; and at least one insert (6), adapted to cooperate with said at least two mould parts to create at least one undercut zone (P) in the ceramic article (2); - a feeding system to feed a mixture under pressure into said casting cavity (5); - a moving device (9) for automatically positioning the insert (6) in coupling with at least one of said two mould parts, when they are in the open configuration; and - a hydraulic system operatively connected exclusively to the at least two mould parts so as to feed a fluid under pressure through them.

Description

[0001] CASTING APPARATUS AND CASTING METHOD FOR MANUFACTURING CERAMIC ARTICLES

[0002] Cross-Reference To Related Applications

[0003] This patent application claims priority from Italian patent application no . 102024000001179 filed on January 23 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] Technical Sector

[0005] The present invention relates to a casting apparatus and method for manufacturing ceramic articles through pressure casting .

[0006] In particular, the present invention finds advantageous but not exclusive application in pressure casting for manufacturing sanitary ware made of ceramic material ( such as washbasins , cisterns , bidets , toilet bowls , etc . ) , to which the following description will make explicit reference without thereby losing generality .

[0007] Background of the Invention

[0008] In this technical field, ceramic articles are generally manufactured by pressure casting a ceramic mixture , known as slip, inside hygroscopic and / or permeable moulds , typically made of resin, to allow the slip to dehydrate during pressure casting, i . e . the water contained in the slip escapes through the pores of the mould .

[0009] Typically, moulds for pressure casting consist of two or more mould parts , depending on the complexity of the article to be made , which are conf igured to fit together in a closed configuration so that at least one casting cavity is defined between them, within which, in use the slip is inj ected at high pressure so that , following the aforementioned dehydration, it penetrates the walls of the mould parts and through them exits the mould, leading to the deposition of the solid part of the slip inside the walls of the mould parts and, therefore , the formation of the ceramic article .

[0010] More speci fically, typically during pressure casting, once the mould parts are placed in a closed configuration and the slip is fed, a pressure greater than 5 bar is applied, preferably from 10 bar to 20 bar, so as to stimulate the so- called slip dehydration and thus lead to the formation of the ceramic article . Fluids , typically air or water, are then fed through the mould parts to facilitate unmoulding, i . e . the separation of the ceramic article formed from the walls of the mould parts . The various mould parts are then pushed apart so that the ceramic article can be removed from the mould .

[0011] However, this process , as such, does not allow for the formation of "undercut" portions of the ceramic article with respect to the opening direction of the di f ferent parts of the mould, i . e . it does not allow for the formation of those parts of the ceramic article that have bas-reliefs forming an acute angle with the opening plane of the di f ferent parts of the mould . In fact , the production of these parts causes problems with the deformability of the ceramic article , making it di f ficult to ej ect it from the mould, and in many cases leading to damage to the article or mould .

[0012] Precisely in order to address these problems , at present , undercut parts are generally formed separately from the rest of the ceramic article and then bonded to the article itsel f , with signi ficant disadvantages in terms of the quality of the finished product , which will inevitably be compromised by the presence of the bonding, but also in terms of the time required to produce the individual ceramic articles .

[0013] Solutions have also been developed involving the use of inserts ( i . e . additional mould parts ) configured to be coupled with other mould parts to allow undercut portions to be made . In particular, known solutions involve the use of support devices to carry these inserts , position them appropriately and hold them in place in the mould during the various casting stages . In addition, these support devices of the known type supply the same inserts with the service fluids required for their operation . These solutions , requiring suitable support devices to carry all the channels necessary for the inserts to function correctly and to hold the inserts in position, are very complex to implement and impose equally complex and rigid handling of the movement of the inserts and other mould parts as well as accurate and rigid control of the operation of the various components of the casting apparatus . This makes these solutions not only very complex, but also very expensive and inflexible .

[0014] The aim of the present invention is to provide a casting method and apparatus for manufacturing ceramic articles by pressure casting, which overcome at least in part the disadvantages of the prior art , al lowing the manufacture of ceramic articles ( in particular, sanitary ware made of ceramic material ) of even complex shapes , thus also with undercut areas , in a simpler and more economical manner .

[0015] Summary

[0016] In accordance with the present invention, a casting method and apparatus are proposed for manufacturing ceramic articles by pressure casting, as claimed in the attached independent claims , and preferably, in any one of the claims dependent directly or indirectly on the mentioned independent claims .

[0017] The claims describe preferred embodiments of the present invention forming an integral part of the present disclosure .

[0018] Brief Description of the Drawings

[0019] The invention wi ll now be described with reference to the accompanying drawings , which show some non-limiting examples of embodiments , wherein :

[0020] - Figures 1 , 2 , 3 , 5 , and 6 show perspective views of di f ferent steps of manufacturing a ceramic bowl according to a first embodiment of the present invention;

[0021] Figures 7A, 7B and 7C show perspective views of successive moments of a step of removing the insert from the ceramic bowl ;

[0022] - Figure 4 shows a longitudinal cross-sectional view of the casting system shown in Figure 3 during the step of placing the slip under pressure into the casting cavity of the mould of the casting apparatus of the present invention;

[0023] - Figures 8 to 14 show perspective views of di f ferent steps of manufacturing a ceramic bowl with a di f ferent structure from the previous one according to a further embodiment of the present invention;

[0024] - Figures 8A, 9A, and 10A are side views of the casting system illustrated in Figures 8 , 9 and 10 respectively; and

[0025] - Figure 11A shows a longitudinal cross-sectional view of the casting system shown in Figure 11 during the step of placing the slip under pressure into the casting cavity of the mould of the casting apparatus of the present invention .

[0026] Detailed Description In the accompanying figures, the number 1 is used to indicate a casting apparatus for manufacturing ceramic articles 2 by means of pressure casting, which ceramic articles 2 are intended, following further processing such as drying, glazing, firing etc., to form finished ceramic products. In particular, the present discussion will explicitly refer to the production of sanitary ware made of ceramic material, such as toilet bowls, bidets, washbasins, etc. without thereby losing its generality.

[0027] In detail, the embodiments shown in the accompanying figures refer to the manufacture of two different types of bowls and illustrate only part of the casting apparatus 1. It is understood that what is illustrated herein remains valid, when varying the shape and / or structure of the mould (in particular, the number of mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E constituting the mould 3 and their shape) , also for the manufacture of any other type of ceramic article 2 having at least one undercut zone.

[0028] More precisely, the term "ceramic article 2" in the present invention means any type of ceramic article 2 that contains at least one undercut zone P and requires moulding by pressure casting. It should be noted that in the present discussion, the expression "undercut zones" is intended to refer to those areas of the ceramic article 2 that have (i.e. are formed by) bas-reliefs forming an acute angle with the opening plane (i.e. with the movement plane) of the various mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E (i.e. heads) of the mould 3.

[0029] With particular reference to the accompanying figures, advantageously, the casting apparatus 1 comprises: a mould 3; a support frame 7 (only partly illustrated in the accompanying figures) which defines at least one housing 8 to receive the mould 3, at least in the closed configuration; and a feeding system (not visible in the accompanying figures) operatively connected to the mould 3 and configured to feed a mixture under pressure, the so-called slip, into a casting cavity 5 of the mould 3 as will be better described below .

[0030] Preferably, this mixture comprises (in particular, consists of) ceramic material suitable for casting sanitary ceramic articles 2 such as washbasins, bidets or toilets in particular as a casting, e.g. a Vitreous China sanitary mixture or a so-called Fine Fireclay sanitary mixture. Advantageously but without limitations, this mixture comprises (in particular, is formed by) approximately 50% a 55% by weight of a plastic and semi-plastic component, which, in turn, comprises (in particular, is formed by) clays and kaolin, and approximately 45-50% of a further non-plastic (or hard) component, which, in turn, comprises (in particular, is formed by) feldspathic minerals, quartz minerals and chamotte.

[0031] It is understood that according to other advantageous but non-limiting and not illustrated embodiments, the casting apparatus 1 could comprise any number of moulds 3, either interconnected or independent of each other.

[0032] Advantageously, the (i.e., each) mould 3 comprises, in turn, at least two mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E (so-called heads) mutually movable between a closed configuration, in which the (in particular, all) mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E are coupled to one another to define, between them, the aforesaid casting cavity 5 for forming a ceramic article 2 (see Figures 3, 4, 11, and 11A) , and an open configuration in which the ( in particular, at least some of the ) mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E are uncoupled from one other ( see Figures 1 , 2 , 5 , 8 , 9 , 10 , 11 , and 12 ) , i . e . are spaced apart from one other and at least one insert 6 ( i . e . , an additional moulded part ) that is configured to cooperate with the other moulded parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, and 4E , in a closed configuration, to create at least one undercut zone P of the ceramic article 2 .

[0033] According to some advantageous but non-limiting embodiments , such as those shown in Figures 1 to 6 , the mould 3 comprises two lateral mould parts 4A and 4B for forming the lower portion of the ceramic article 2 , in the illustrated case of the bowl . These lateral mould parts 4A and 4B are connected to the support frame 7 , and arranged facing each other and, advantageously but not l imitedly, mutually movable towards or away from one other, moving precisely from the open to the closed configuration, and vice versa . The mould 3 further comprises a male mould part 4C which is movable with respect to the lateral mould parts 4A and 4B between the aforementioned closed and open configuration, and intended in the closed configuration to be at least partially inserted into the lateral mould parts 4A and 4B so as to form the upper part of the same bowl 2 .

[0034] This mould 3 , advantageously but not limitedly, comprises a single insert 6 intended to be coupled with the male mould part 4C, when the mould 3 is in the open configuration, as will be better explained later in this discussion, and to co-operate with the male mould part 4C and the other lateral mould parts 4A and 4B, in the closed configuration, to form an undercut zone P, e . g . in the illustrated case , the rim of the bowl 2 .

[0035] According to other advantageous but non-limiting embodiments , such as those illustrated in Figures 8 to 12 , the mould 3 is configured to shape another type of bowl 2 and comprises four lateral mould parts 4A, 4B, 4C, and 4D slidably connected to the support frame 7 and intended to form the lower portion of the ceramic article 2 , in the illustrated case of the bowl 2 ; and a male mould part 4E movable with respect to the lateral mould parts 4A, 4B, 4C, and 4D between the closed configuration and the open configuration and intended, in the closed configuration, to be placed between the four lateral mould parts 4A, 4B, 4C, and 4D so as to form the upper part of the ceramic article 2 itsel f .

[0036] Advantageously but not limitedly, in this case , the lateral mould parts 4A, 4B, 4C, and 4D are arranged facing one other two by two and are mutually movable towards and away from one another, moving precisely from the open configuration to the closed configuration, and vice versa, to define a compartment within which, in the closed configuration, the male mould part 4E is intended to be inserted . Even more advantageously but not limitedly, said mould 3 comprises two inserts 6 coupled to one other, or a two-part insert 6 intended to be coupled to said lateral mould parts 4A, 4B, 4C, and 4D, when the mould 3 is in an open configuration, as will be further explained below, and to cooperate with these lateral mould parts 4A, 4B, 4C, and 4D and with the male mould part 4E , when the mould 3 is in the closed configuration, to form an undercut zone P, for example in the case illustrated in Figures 8 to 12 , the siphon of the bowl 2 . Thanks to the presence of thi s insert 6 , it is also possible to produce ceramic articles 2 with complex shapes without the need ( or at least minimi sing the need) for post- formation bonding . Advantageously, the casting apparatus 1 of the present invention further comprises a moving device 9 operable to position and release the insert 6 ( in particular, each insert 6 ) in coupling with at least one of the mould parts 4 , when these are in the open configuration . The ability to position the insert 6 or inserts 6 automatically coupled to a mould part 4C or between 4C and 4D and release them in coupling on the mould part 4C or between 4C and 4D itsel f allows the productivity of the casting apparatus 1 to be increased by reducing the costs and footprint compared to known solutions of the prior art involving complex support apparatuses that hold the inserts 6 in place during the operation of the casting apparatus 1 .

[0037] Advantageously but not limitedly, the moving device 9 comprises : a holding unit 10 to hold and release at least one insert 6 ; and a moving structure 11 , which carries the holding unit 10 and is movable between a release position, in which the holding unit 10 is arranged so as to position ( i . e . release ) the insert 6 in coupling with at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E in the open configuration ( see , for example Figures 2 , 9 and 9A) , and a second pos ition, in which the holding unit 10 is on the outside of the housing 8 so as not to interfere with the mould 3 when it is in the closed configuration; in other words , it is distant from the mould 3 ( see , for example , Figures 5 , 10 , 10A) .

[0038] Advantageously, but not limitedly, the insert 6 is configured and mounted so that it is separable from all the mould parts 4A, 4B, 4C, 4D, 4E and from the moving device 9 (in particular, from the holding device 10) .

[0039] According to some non-illustrated embodiments, the casting apparatus 1 comprises at least one insert 6 storing station (not illustrated and known per se) comprising a plurality of inserts 6 and the moving device 9 is operable to automatically move at least one insert 6 of said plurality of inserts from the storing station into coupling with one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E in an open configuration.

[0040] Advantageously but not limitedly, in this case, the second position outside the housing 8 coincides with the insert 6 storing station.

[0041] According to some advantageous but non-limiting embodiments such as those illustrated in the accompanying figures, the moving structure 11 of the moving device 9 comprises (in particular, is) a robotic arm; even more advantageously but not limitedly, an anthropomorphic arm. This advantageously allows greater flexibility and freedom of movement by making the automatic positioning of the insert 6 easier and quicker.

[0042] In combination or alternatively, in accordance with certain advantageous but non-limiting embodiments (such as, for example, those illustrated in Figures 1 and 2) , the holding unit 10 comprises (in particular, is formed by) a plurality of suction members 12 of a known type, e.g. suction cups, operable to hold or release the insert 6 (i.e. each insert 6) .

[0043] Alternatively, or in combination, according to some advantageous but non-limiting embodiments (such as, for example, those illustrated in Figures 8, 8A, 9, 9A, 10, and 10A) , the holding unit 10 comprises (in particular, consists of ) two clamping elements 13 mutually movable between a clamping position and a release position, and an operating cylinder 14 to operate clamping elements 13 between the clamping position and the release position . Advantageously, but not limitedly, the casting apparatus 1 also comprises a control system 15 ( only schematically illustrated in Figures 1 and 8 ) configured to control the activation of the moving device 9 so as to automatically arrange the insert 6 ( in particular, each insert 6 ) in coupling with one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E , in the open configuration . Even more advantageously but not limitedly, the control system 15 is configured to actuate the moving device 9 to take at least one insert 6 from the insert storing station and trans fer the insert 6 to release it in coupling with at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E , when the mould 3 is in the open configuration and to disengage the mould 3 , ( in particular, out of the aforementioned housing 8 ) before it moves to the closed configuration .

[0044] In other words , the control system 15 is configured to activate the moving device 9 so that it positions the insert 6 in coupling with at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E , releases it onto said at least one mould part 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E , when the mould 3 is in an open configuration and then moves away from the mould 3 , before the latter assumes the closed configuration, so as not to interfere with the mould 3 itsel f in the closed configuration, for example during casting operations . .

[0045] In more detail , according to some advantageous but nonlimiting embodiments such as , for example , the one illustrated in Figures 1 to 6 , the moving device 9 is activated to position the insert 6 in coupling with the male mould part 4C . In this case , advantageously but not limitedly, the insert 6 comprises a magnet (not visible in the accompanying figures ) and the male mould part 4C to which this is attached comprises a magnetic coupling element ( also not visible in the accompanying figures ) configured to interact with the magnet present in the male mould part 4C and generate a magnetic attraction force such as to hold the insert 6 attached to the male mould part 4C in position . In this case , advantageously but not limitedly, the moving device 9 is configured ( in particular, the holding unit 10 is configured) to place the insert 6 in contact with the male mould part 4C so that it remains in position under the action of the magnetic attraction force . Advantageously, but not limitedly, the magnet and magnetic coupling element are conf igured / si zed to generate a magnetic attraction force greater than the gravitational force to which the insert 6 is subj ected .

[0046] According to other advantageous but non-limiting embodiments such as , for example , those illustrated in Figures 8 to 12 , the moving device 9 is configured to release the insert 6 in two parts , or the two inserts 6 , resting on two of the lateral mould parts 4A, 4B, 4C, and 4D ( in particular, between the lateral mould parts 4C and 4D) in the open configuration . Speci fically, in this case , the operating cylinder 14 of the moving device 9 is activated to cause the clamping elements 13 to release the insert 6 in two parts , or the two inserts 6 , resting on the lateral mould parts 4C, and 4D in the open configuration .

[0047] According to some advantageous but non-limiting embodiments , the casting plant 1 also comprises an actuation assembly 16 for the mutual movement of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E from the closed to the open configuration . Advantageously but not limitedly, the control system 15 is configured to control the operation of the actuation assembly 16 as well .

[0048] More speci fically, advantageously but not limitedly, the control system 15 is configured to control the operation of the moving device 9 , when the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E are in the open configuration so that it appropriately pos itions the insert 6 or inserts 6 ( e . g . , in any of the ways set out above ) , and to control the operation of the actuating assembly 16 , so that the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E shi ft from the open conf iguration to the closed configuration, only once the moving device 9 ( in particular, the holding unit 10 ) has positioned the insert 6 in engagement with a mould part 4C or 4C, 4D ( in particular, as mentioned above , in contact with the male mould part 4C - see Figures 1 , 2 , and 4 , or in contact with two of the lateral mould parts 4C, and 4D - see Figures 8 , 8A, 9 , 9A) and moved outside the housing 8 , in particular when the moving structure 11 of the moving device 9 is in the above described second position .

[0049] According to some advantageous but non-limiting embodiments , the actuation assembly 16 comprises at least one support 16A arranged on the frame 7 and operatively connected to at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E , and at least one movable support 16C which carries at least one other mould part 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E , and is movable towards and / or away from the support 16A along a direction A to shi ft from the closed configuration to the open configuration, and vice versa .

[0050] In detail , with particular reference to Figures 1 to 6 , according to certain advantageous but non-limiting embodiments , the actuation assembly 16 comprises : a support 16A connected ( in particular, integrally) to the frame 7 and to the lateral mould parts 4A and 4B and configured to allow at least one mutual movement of the lateral mould parts 4A and 4B so that a compartment shaped in a complementary manner to the male mould part 4C remains defined between them to receive said male mould part 4C in a closed configuration; and a further movable support 16C which carries the male mould part 4C and is movable towards and / or away from the support 16A along the aforementioned direction A so that the male mould part 4C can, by shi fting from the open configuration to the closed configuration, insert itsel f into the compartment defined by the lateral mould parts 4A and 4B, or move away from the lateral mould parts 4A and 4B, or move out of this compartment by shi fting from the closed configuration to the open configuration . According to some embodiments , this mobile support 16C compri ses ( in particular, consists of ) a carriage (not visible in the accompanying figures ) . Alternatively or additionally, the movable support 16C comprises ( in particular, consists of ) a guide system, which is suitable for guiding at least the male mould part 4C towards or away from the lateral mould parts 4A and 4B along the direction A, e . g . along rails .

[0051] According to other advantageous but non-limiting embodiments , such as those illustrated in Figures 8 to 12 , the actuation assembly 16 comprises : a pair of supports 16A each connected to the frame 7 and to the lateral mould parts 4C and 4D and adapted to allow at least one of the lateral mould parts 4C and 4D to slide with respect to one other to move towards one other, in the closed configuration, and to move away from each other, in the open configuration; a further pair of supports 16B adapted to carry the lateral mould parts 4A and 4B mutually movably towards and / or away from each other and with respect to the pair of supports 16A so that , in the closed configuration, the lateral mould parts 4C and 4D are coupled to the lateral mould parts 4A and 4B to define ( in particular, laterally delimit ) a compartment shaped in a complementary manner to the male mould part 4E ; and a respective movable support 16C which carries the male mould part 4E towards and / or away from the other supports 16A and 16B along the aforementioned direction A so that the male mould part 4E can be coupled to the lateral mould parts 4A, 4B, 4C and 4D shi fting from the open configuration to the closed configuration, or vice versa, moving away from the lateral mould parts 4A, 4B, 4C and 4D, shi fting from the closed configuration to the open configuration .

[0052] According to some advantageous but non-limiting embodiments , again, at least the mobile support 16C comprises ( in particular, consists of ) a carriage . Alternatively or additionally, the movable support 16C comprises ( in particular, is formed by) a guide system, for example comprising rails , which is adapted to guide at least the male mould part 4E towards or away from the lateral mould parts 4A, 4B, 4C and 4D along the direction A. Alternatively or additionally, the supports 16B also comprise ( in particular, consist of ) a carriage . Alternatively or additionally, the supports 16B comprise ( in particular, consist of ) a guide system, e . g . comprising rails , which is adapted to guide at least the mould parts 4A, 4B away from each other or away from the pair of supports 16A.

[0053] According to some advantageous but non-limiting embodiments not i llustrated, the at least one movable support 16C comprises ( in particular, cons ists of , or coincides with) a robotic arm adapted to ( in particular, operable by the control system 15 to ) move the at least one mould part 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E , ( e . g . , the male mould part 4C or 4E in the embodiments of the accompanying Figures ) along the direction A to bring the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E closer to each other ( shi fting from the open configuration to the closed configuration) , or to move the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E away from each other ( shi fting from the closed configuration to the open configuration) . More speci fically, in this case , the control system 15 is conf igured to control this robotic arm to bring the male mould part 4C towards or away from the lateral mould parts 4A, 4B in the embodiments il lustrated in Figures 1 , 2 , 3 ) or to bring the male mould part 4E closer to the other four lateral mould parts 4A, 4B, 4C, and 4D, in the embodiments illustrated in Figures 10 , 10A, 11 and 12 . This structure of the actuation assembly is particularly advantageous , allowing the robotic arm to be able to operate on the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E, quickly and with high flexibility / freedom of movement .

[0054] Advantageously, but not limitedly ( as is usually the case in the field of pressure casting) , the mould 3 is also provided with a hydraulic system operationally connected exclusively to the mould parts 4A, 4B, 4C or 4A, 4B , 4C, 4D, 4E to feed a pres surised fluid through these mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E . The mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E are , therefore , equipped with respective hydraulic circuits (known and not illustrated) connected to at least one suction device (e.g. vacuum pump) , one compression device, one water supply (e.g. centrifugal pump) and / or one air supply device. These circuits advantageously enable correct and easier unmoulding of the ceramic articles 2 and are also used for the maintenance of the mould 3. Advantageously, but not necessarily, the mould 3, in particular all the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E, comprise (in particular, are made of) hygroscopic and / or permeable material; even more specifically, porous resin.

[0055] Advantageously, but not necessarily, the mould 3 comprises (in particular is made of) , more particularly, all the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E, comprise (in particular, are made of) porous resin; more advantageously, a resin having a (total open) porosity of at least 10%, in particular up to 50% (more particularly, up to 28%) by volume, with respect to the total volume of the main body 13.

[0056] The porosity is measured with mercury porosimetry with a Pascal 140 / 240 Thermo Fisher Scientific Porosimeter (following the instructions attached to it) . The principles and the operation of the mercury porosimetry are well known and are for example described in: Mercury Porosimetry : a General (Practical) Overview, Part. Part. Syst. Charact . 23 (2006) 1-11, Herbert Giesche, DOI: 10.1002 / ppsc .200601009; Characterization of Porous Solids and Powders : Surface Area, Pore Size and Density, S. Lowell, Joan E. Shields, Martin A. Thomas e Matthias Thommes, Kluwer Academic Publishers 2004, ISBN 1-4020-2302-2 (HB) , ISBN 1-4020-2302-0 (e-book) . In particular, porosity is measured according to the provisions of ISO standard 15901-1:2016. Total open porosity is the porosity measured by considering open pores (and not closed pores) , i.e. the pores that are accessible by a fluid (ISO 15901-1:2016) .

[0057] Advantageously, but not necessarily, the mould 3 (in particular all the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E; more specifically, the aforementioned resin forming it / them) has pores with a median diameter from 0.5 (in particular, from about 5 pm) to 80 pm (in particular, to about 15pm) .

[0058] Unless otherwise specified, in the present text, by diameter of a pore is meant the limiting diameter, i.e. the diameter of a circle having the same area as the smaller (cross) section of the pore.

[0059] The median pore diameter is measured with mercury porosimetry with a Pascal 140 / 240 Thermo Fisher Scientific Porosimeter (following the instructions attached to it) . The principles and operation of mercury porosimetry are well known. In particular, the median pore diameter is measured according to the provisions of ISO standard 15901-1:2016.

[0060] Note that by median diameter is meant the diameter corresponding to the fiftieth percentile of the pore volume, i.e. the diameter for which half of the pore volume is in the largest pores and half of the pore volume is in the smallest pores (ISO 15901-1:2016, in particular paragraph 3.16) .

[0061] Advantageously but not limitedly, the insert 6 (i.e. each insert 6) is disconnected (i.e. not connected, more specifically, isolated) from the aforementioned hydraulic system. In other words, the insert 6 or inserts 6 do not include / comprise (in particular, it is devoid of) ducts or hydraulic circuits; more specifically, these are so-called passive inserts 6, which do not include active components.

[0062] It is hereby specified that in the present discussion the expression "passive insert 6" is intended to refer to an insert 6 without ducts, service ducts, etc. used to supply the service fluids to the various mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E; even more advantageously, but not limitedly, it means an insert 6 disconnected from the aforementioned (known) hydraulic circuits used for supplying operating fluids to the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E.

[0063] The absence of ducts and connections in the insert 6, hence the adoption of a passive insert 6, simplifies the handling of the mould 4 in the various operating steps, with the same quality of the ceramic articles 2, as will be better explained below.

[0064] Even more advantageously but not limitedly, the insert 6 (i.e. each insert 6) is made of (in particular, consists of) porous resin, such as that described above for the mould parts 4.

[0065] Even more advantageously but not limitedly, the insert 6 (i.e. each insert 6) has a water content, advantageously measured by the gravimetric method, ranging between 50% and 100% of the total porosity.

[0066] Advantageously but not limitedly, the casting apparatus 1 further comprises a transfer device (known per se and not illustrated herein) and at least one extraction station (not illustrated) and placed at a certain distance from the housing 8, wherein the ceramic article 2 once removed (i.e. unmoulded) from the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E, is transferred, by said transfer device. Even more advantageously, such a transfer device is configured to transfer the ceramic article 2 with the insert 6 still attached thereto from the housing 8 to such an extraction station, where the extraction of the insert (s) from the ceramic article 2 takes place, either manually or automatically (see Figures 6, 7A, 7B, and 7C) .

[0067] According to some advantageous but non-limiting embodiments, such as those illustrated in Figures 7A and 7B, in fact, the casting apparatus 1 also comprises a robotic extraction device 17 configured to take the insert 6 while it is still attached to the ceramic article 2 and to extract it (i.e. decouple it) automatically from said ceramic article 2.

[0068] With particular reference to Figures 7A, 7B and 7C, advantageously but not limitedly, the extraction device 17 comprises: a holding unit 18 for the insert 6; and a moving structure 19 (advantageously, but not limitedly, comprising- i.e. consisting of- a robot) which carries the holding unit 18 and is movable between a first position, wherein the holding unit 18 is arranged to hold (grip) the insert 6 in coupling with the ceramic article 2 (see, for example, Figure 7A) , and a second position, wherein the holding unit 18 is external to the ceramic article 2 (see, for example, Figure 7B) .

[0069] According to another aspect of the present invention, a casting method is proposed for manufacturing ceramic articles 2.

[0070] Advantageously, this casting method is adapted to allow the manufacture of ceramic articles 1 by means of a casting apparatus 1, which, in turn, comprises at least: a support frame 7 (only partly illustrated in the accompanying figures) and a mould 3 (advantageously but not limitedly of the type described above with reference to the casting apparatus 1 ) which, in turn, comprises at least two mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E mutually movable between a closed configuration, wherein they are coupled to one another to define between them a casting cavity 5 , and an open configuration, wherein they are uncoupled from one other and at least one insert 6 as will be explained below .

[0071] More advantageously, but not limitedly, this casting method is actuated with a casting apparatus 1 described above , i . e . carried out according to one of the embodiments presented above .

[0072] Advantageously, the casting method comprises the following steps : an insert 6 positioning step, during which the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E are in the open configuration and a moving device 9 ( advantageously but not limitedly of the type described above with reference to the casting apparatus 1 ) automatically places at least one insert 6 in coupling with at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E ( in particular, as explained above in relation to the casting apparatus 1 in coupling to the male mould part 4C according to certain embodiments such as those illustrated in Figures 1 and 2 , or in coupling to the lateral mould parts 4C, 4D according to other embodiments such as those illustrated in Figures 8 , 8A, 9 and 9A) ; a closing step ( at least partially) subsequent to the insert positioning step 6 , during which the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E are mutually moved from the open configuration to the closed configuration so as to define the casting cavity 5 for forming a ceramic article 2 and the insert 6 , coupled to at least one of the mould parts 4C or 4C, 4D, cooperates with the two mould parts 4A, 4B, or 4A, 4B, 4E , to allow the formation of at least one undercut zone P of the ceramic article 2 ; and a casting step, during which a feeding system (not illustrated in the accompanying figures and known per se) feeds a pressurised mixture , the so-called slip, into the casting cavity 5 , which is pressurised to form the ceramic article 2 .

[0073] According to some advantageous but non-limiting embodiments , the insert positioning step 6 comprises : a grabbing sub-step , during which a holding unit 10 , which is part of the moving device 9 ( and which advantageously but not limitedly is implemented according to one of the embodiments described above ) grasps the insert 6 from an insert storing station (not illustrated in the accompanying Figures and known per se) ; a moving sub-step, during which a moving structure 11 , which carries the holding unit 10 , is part of the moving device 9 ( and advantageously but not limitedly is made according to one of the embodiments described above ) , moves the holding unit 10 from the insert storing station ( in particular , from the aforementioned second position at the insert storing station) towards one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E ( in particular, towards the aforementioned release position at - or in proximity to - at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E ) ; a release sub-step, during which the holding unit 10 releases / places the insert 6 in coupling with one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E ( in particular with the male mould part 4C in the embodiment of Figures 1 to 6 and between the mould parts 4C, 4D in the embodiment of Figures 8 to 12 ) ; and a second moving step, during which the moving structure 11 moves the holding unit 10 to the outside of the mould 3 , in particular outside the above-described housing 8 defined by the support frame 7 , so that the moving device 9 does not interfere with the mould 3 in the subsequent steps of the casting method . Advantageously but not limitedly, the moving structure 11 of the movement device 9 comprises ( in particular, is ) a robotic arm, even more advantageously but not limitedly of an anthropomorphic type , carrying the holding head 10 .

[0074] Advantageously, the casting method further comprises an unmoulding step, during which the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E are moved from the closed configuration to the open configuration ( in particular, so that the at least one male mould part 4C or 4E moves away from the remaining mould parts 4A and 4B, or 4A, 4B, 4C and 4D) , the ceramic article 2 remains connected to at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E ( in particular, to the lateral mould parts 4A and 4B or to the lateral mould parts 4A, 4B, 4C and 4D) and the insert 6 is attached to the ceramic article 2 ; a removal step, during which the ceramic article 2 with the insert 6 attached thereto is separated from the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E to which it was attached ( i . e . from the lateral mould parts 4A and 4B or the lateral mould parts 4A, 4B, 4C and 4D ) and an insert removal step 6 , during which the insert 6 is removed from the ceramic article 2 ( see , for example , Figures 7A to 7C ) .

[0075] Advantageously, but not limitedly, such insert 6 removal step is automatic and involves operating a robotic extraction device 17 so as to uncouple the insert 6 ( speci fically, each insert 6 ) from the article 2 .

[0076] Even more advantageously but not l imitedly, the casting method comprises a trans fer step ( at least partially) subsequent to the unmoulding step and ( at least partially) preceding the insert 6 removal step during which, the ceramic article 2 with the insert 6 , or inserts 6 , attached thereto is trans ferred to an extraction station, advantageously but not limitedly, at a distance defined by the support frame 7 of the mould 3 . In this case , even more advantageously but not limitedly, the insert 6 removal step is carried out at this extraction station .

[0077] According to some advantageous but non-limiting embodiments , during the unmoulding step, a hydraulic system (not illustrated in the accompanying figures and known per se) feeds a pressurised fluid through the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E , induces the detachment of the ceramic article 2 consisting of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E while the insert 6 , in interference with the undercut zone P of the ceramic article 2 , remains attached to the ceramic article 2 itsel f .

[0078] In particular, advantageously but not limitedly, once the ceramic article 2 has been formed, the insert 6 , in interference with the undercut zone P of the ceramic article 2 , remains attached to the ceramic article 2 itsel f , even when the mould part 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E to which it was coupled during the positioning of the insert 6 moves away from the remaining mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E ( i . e . also when the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D, 4E shi ft from the closed configuration to the open configuration after casting) .

[0079] Even more advantageously, in non-limiting embodiments in which the insert 6 comprises a magnet ( see , for example , the embodiment illustrated in Figures 1 to 6 ) the magnetic attraction force developed between the magnet and the magnetic coupling element is greater than the force of gravity to which the insert 6 is subj ected, but is less than the holding force exerted by the undercut zone P on the insert 6 itsel f ( see , in particular, Figure 6 , wherein the insert 6 is shown to remain integral with the ceramic article 2 even after the unmoulding step due to the action exerted by the undercut zone P .

[0080] The present invention has numerous advantages , including the following ones .

[0081] The method and the casting apparatus 1 of the present invention, by allowing automatic positioning of the inserts 6 , enable the production of ceramic articles 2 even of complex shapes while maintaining high quality standards and eliminating, or at least reducing, the bonding required to form the ceramic article 2 .

[0082] In addition, this solution ensures high production ef ficiency . In fact, the automatic positioning of the inserts 6 allows , at the same time , to reduce labour with all the advantages in terms of costs , but also in terms of safety as well as precision and speed of operation .

[0083] Furthermore , since the insert 6 can be disconnected from the moving device 9 , it can be inspected, washed, serviced, etc . , once it has been removed from the mould 3 in a simple manner and without any downtime ; the moving device 9 can in fact , at the same time , place another insert 6 in coupling with at least one of the mould parts 4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E , with obvious advantages in terms of production speed .

[0084] The technical solution of the invention allows , at the same time , appreciable improvements in complexity, cost and space . In fact , with respect to solutions involving inserts 6 provided with ducts for the service fluids , it al lows for a considerable simpli fication of the hydraulic system but also of the structure of the insert 6 itsel f , which is simpler and less expensive , and with respect to solutions requiring the need for support systems , for example robots , intended to remain attached to the insert 6 also during casting in order to keep the inserts in position, the present invention allows for a considerable reduction in the complexity of casting operations and also of the overall dimensions of the casting apparatus 1 , with the same quality of the ceramic articles 2 .

Claims

CLAIMS1. A casting apparatus (1) for manufacturing ceramic articles (2) through pressure casting; said casting apparatus (1) comprising: at least one mould (3) , which, in turn, comprises: at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) mutually movable between a closed configuration, in which they are coupled to one another to define, between them, a casting cavity (5) for forming a ceramic article (2) , and an open configuration, in which they are uncoupled from one another; and at least one insert (6) , which is configured to cooperate with said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) , in said closed configuration, to create at least one undercut zone (P) in said ceramic article (2) ; a feeding system configured to feed a mixture under pressure into said casting cavity (5) ; a moving device (9) , which can be operated for positioning and releasing said at least one insert (6) in coupling with at least one of said two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) , when they are in the open configuration; and a hydraulic system operatively connected exclusively to said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) so as to feed a fluid under pressure through said mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) .

2. The casting apparatus (1) according to claim 1, comprising a support frame (7) , which defines at least one housing (8) to receive said mould (3) at least in the closed configuration; wherein said moving device (9) comprises: a holding unit (10) to hold and release at least oneinsert (6) ; and a moving structure (11) , which carries said holding unit (10) and is movable between a first position, in which said holding unit (10) is arranged so as to position said insert (6) in coupling with at least one of said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) in the open configuration, and a second position, in which said holding unit (10) is on the outside of said housing (8) .

3. The casting apparatus (1) according to claim 2, wherein said moving structure (11) comprises (in particular, is) a robotic arm.

4. The casting apparatus (1) according to claim 2 or 3, wherein said holding unit (10) comprises: two clamping elements (13) mutually movable between a clamping position and a release position and an operating cylinder (14) to operate said clamping elements (13) between said clamping position and said release position.

5. The casting apparatus (1) according to claim 2 or 3, wherein said holding unit (10) comprises (in particular, consists of) a least one suction member (12) , which can be operated so as to hold or release said at least one insert (6) .

6. The casting apparatus (1) according to any one of the claims from 2 to 5, comprising: an actuation assembly (16) to mutually move said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) from the closed configuration to the open configuration and vice versa and a control system (15) ; said actuation assembly (16) comprising: at least one first support (16A) , which is arranged on said frame (7) and is operatively connected to at least one said at least twomould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) , and at least one second support (16B) , which is movable relative to said first support (16A) along a first direction (A) to shift from said closed configuration to said open configuration and vice versa; said control system (15) being configured to cause the activation of said moving device (9) , when said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) are in the open configuration, and to cause said actuation assembly (16) to shift from said open configuration to said closed configuration, once said holding unit (10) has released said insert (6) coupled to said at least one mould part (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) and said moving structure (11) is in said second position.

7. The casting apparatus (1) according to any one of the preceding claims, wherein: at least one first mould part (4C) of said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) is movable relative to the other mould parts (4A, 4B) between said closed configuration and said open configuration; said at least one insert (6) comprises a magnet and said at least one first mould part (4C) comprises a magnetic coupling element configured to interact with said magnet and generate a magnetic attraction force; said moving device (9) is configured to place said insert (6) in contact with said at least one first mould part (4C) so that said insert (6) remains in position due to the action of the magnetic attraction force; said magnetic attraction force being greater than the force of gravity acting upon said insert (6) .

8. The casting apparatus (1) according to any one ofthe claims from 1 to 6, wherein: said moving device (9) is configured to release said at least one insert (6) so that it rests on at least one of the said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) .

9. The casting apparatus (1) according to any one of the preceding claims, wherein said at least one insert (6) is manufactured as one single piece and comprises (in particular, is made of) a porous resin.

10. The casting apparatus (1) according to any one of the preceding claims, wherein said insert (6) is disconnected from (i.e., is not connected to) said hydraulic system.

11. A casting method for manufacturing ceramic articles (2) by means of a casting apparatus (1) comprising at least one mould (3) , which, in turn, comprises at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) mutually movable between a closed configuration, in which they are coupled to one another to define, between them, a casting cavity (5) , and an open configuration, in which they are uncoupled from one another; said casting method comprises the following steps : an insert (6) positioning step, during which said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) are in the open configuration and a moving device (9) places and releases, in an automatic manner, at least one insert (6) in coupling with at least one of said mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) ; a closing step, which is subsequent to said insert (6) positioning step and during which said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) are mutually moved from said open configuration to said closedconfiguration so as to define said casting cavity (5) for forming a ceramic article (2) and said insert (6) , coupled to at least one of the mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) and separate from said moving device (9) , cooperates with said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) so as to form an undercut zone (P) of said ceramic article (2) ; a casting step, during which a feeding system feeds a mixture under pressure into said casting cavity (5) and said casting cavity (5) is put under pressure so as to form said ceramic article (2) having at least one undercut zone (P) ; an unmoulding step, during which said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) are moved from said closed configuration to the open configuration, said ceramic article (2) remains connected to at least one of said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) and said insert (6) sticks to said ceramic article (2) ; an extraction step, during which said ceramic article(2) is separated from said at least one of said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) with said insert ( 6 ) ; and an insert (6) removal step, during which said insert (6) is removed from said ceramic article (2) .

12. The casting method according to claim 11, wherein said casting apparatus (1) comprises a support frame (7) , which defines at least one housing (8) to receive said mould(3) at least in the closed configuration, and, during said insert (6) positioning step, said moving device (9) , after having placed said insert (6) in coupling with said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) ,releases said insert (6) and moves away from said mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) , before said closing step, so as to assume a position on the outside of said housing ( 8 ) .

13. The casting method according to claim 11 or 12, wherein said insert positioning step (6) comprises: a grabbing sub-step, during which a holding unit (10) , which is part of said moving device (9) , grabs said insert (6) from an insert storing station; a first moving sub-step, during which a moving structure (11) , which is part of said moving device (9) , moves said holding unit (10) from said insert storing station to a release position, close to at least one of said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) ; a release sub-step, during which said holding unit (10) places said insert (6) so that it is coupled to one of said at least two mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) ; and a second moving sub-step, at least partially prior to said closing step, during which said moving structure (11) moves said holding unit (10) from said release position to the outside of said mould (3) so that it does not interfere with said mould (3) during said closing and casting steps.

14. The casting method according to claim 11 or 12 or 13, wherein, during said unmoulding step, a hydraulic system feeds a fluid under pressure exclusively through at least said mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) so as to cause the ceramic article (2) to detach itself from said mould parts (4A, 4B, 4C or 4A, 4B, 4C, 4D and 4E) , while said at least one insert (6) , interfering with the undercut zone (P) of the ceramic article (2) and disconnected from said hydraulic system, remains attached to the ceramicarticle ( 2 ) .

15. The casting method according to any one of the claims from 11 to 14 carried out by means of a casting apparatus (1) according to one of the claims from 1 to 10.

16. The casting method according to any one of the claims from 11 to 15, wherein, during said insert (6) removal step, a robotic extraction device (17) automatically uncouples said insert (6) from the ceramic article (2) .

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