WO2022043966A1

WO2022043966A1 - Apparatus for the non-destructive quality control of a ceramic manufactured article

Info

Publication number: WO2022043966A1
Application number: PCT/IB2021/057949
Authority: WO
Inventors: Fabio TERZI; Sergio Marcaccioli; Giuliano FERRARI; Margherita FANELLI
Original assignee: Sicer S.P.A.
Priority date: 2020-08-31
Filing date: 2021-08-31
Publication date: 2022-03-03

Abstract

The apparatus (1) for the non-destructive quality control of a ceramic manufactured article, comprising: a thermalization assembly (3) of a ceramic manufactured article (2) configured to allow the maintenance of the ceramic manufactured article (2) at a constant predefined temperature, the thermalization assembly comprising supporting means (6, 15) of the ceramic manufactured article (2); measurement means (4) for measuring at least one homogeneity parameter of the ceramic manufactured article (2); wherein the measurement means (4) are adapted to detect at least one of the following thermal parameters (P_TR) of the ceramic manufactured article (2): thermal conductivity, heat flow, thermal resistance, heat transfer coefficient, thermal transmittance, specific heat, Biot number, Nusselt number, R value and U value.

Description

APPARATUS FOR THE NON-DESTRUCTIVE QUALITY CONTROL OF A CERAMIC MANUFACTURED ARTICLE

Technical Field

The present invention relates to an apparatus for the non-destructive quality control of a ceramic manufactured article.

Background Art

In the production process of ceramic manufactured articles, quality control thereof is of special importance.

As is well known, quality control is the set of actions aimed at identifying and monitoring the quality standards of ceramic manufactured articles.

These operations are aimed, in particular, at detecting any variations in the mechanical properties of the ceramic manufactured article.

In order to ensure compliance with the requirements, quality control is carried out by performing systematic tests and inspections on raw materials, the ceramic mixture, production processes and fired ceramic manufactured articles, also using specific instruments or machinery.

These tests are based on the detection of several parameters, such as e.g. density, the variation of which affects the mechanical properties of ceramic manufactured articles.

In detail, density detection is carried out by means of tests and inspections carried out on raw ceramic manufactured articles and which do not allow monitoring the variations which the ceramic manufactured article undergoes during the subsequent phases of the production process.

For example, tests and inspections carried out on the raw ceramic mixture do not detect or even predict any variations which the mixture itself undergoes during the firing cycle.

At the same time, tests and inspections on fired ceramic manufactured articles can only be carried out by using destructive techniques that cause the ceramic manufactured articles themselves to break.

For example, in order to analyze the density of a fired ceramic manufactured article, the latter has to be cut and this results in a huge waste of material. In addition to this, there is nowadays a particular need to develop apparatuses which allow the non-destructive quality control of ceramic manufactured articles, thus making it possible to measure the state of homogeneity of the fired ceramic manufactured articles in order to quantify the residual mechanical stress.

Description of the Invention

The main aim of the present invention is to devise an apparatus for the nondestructive quality control of a ceramic manufactured article which allows analyzing the homogeneity thereof at the end of the firing cycle.

Within this aim, one object of the present invention is to devise an apparatus for the non-destructive quality control of a ceramic manufactured article which allows quantifying residual mechanical stress.

Another object of the present invention is to devise an apparatus for the nondestructive quality control of a ceramic manufactured article which enables the aforementioned drawbacks of the prior art to be overcome within the framework of a simple, rational, easy and effective to use as well as affordable solution.

The aforementioned objects are achieved by the present apparatus for the nondestructive quality control of a ceramic manufactured article having the characteristics of claim 1.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more apparent from the description of a preferred, but not exclusive, embodiment of an apparatus for the non-destructive quality control of a ceramic manufactured article, illustrated by way of an indicative, yet non-limiting example, in the accompanying tables of drawings wherein:

Figure 1 is a schematic representation of the apparatus according to the invention;

Figures 2 and 3 are schematic representations of the apparatus according to the invention in an alternative embodiment;

Figure 4 is a schematic representation of the apparatus according to the invention in a further embodiment. Embodiments of the Invention

With particular reference to these figures, reference numeral 1 globally indicates an apparatus for the non-destructive quality control of a ceramic manufactured article.

It is specified that within the scope of the present disclosure, the expressions “ceramic manufactured article” or “ceramic material” relate to materials that are optionally also vitreous, such as glass-ceramics, or agglomerates.

Preferably, the ceramic manufactured article 2 is selected from the group comprising: ceramic tiles, furniture, tableware, sanitary ware and technical ceramics.

In detail, tiles may be, e.g., raw tiles, fired tiles, stoneware, porcelain stoneware, mono-porous ceramic, single-fired ceramic, double-fired ceramic, klinker, third- fired and fourth-fired.

In addition, the term “tiles” relates indiscriminately to tiles for home, commercial, industrial use as well as service use of various kinds, which can be employed as floor, exterior wall and interior wall coverings.

Tablew are and furniture, in turn, may be of the type of raw tablew are and fired tableware and comprises household items such as crockery, kitchen tops and parts of furniture.

Sanitary ware comprises, e.g., sanitary ware, sinks and washbasins, shower trays.

At the same time, it is specified that the expression “technical ceramics” relates to materials used for the manufacture of components for the mechanical and biomedical sector.

The ceramic manufactured articles 2 comprise a main body covered with one or more layers of material selected alternatively from: ceramic, vitreous or organic.

In the context of the present disclosure, the term “agglomerates” relates to tiles or slabs made of inorganic material of the type of quartz or glass, which form a coherent material thanks to the use of an inorganic or organic polymeric binding material. Preferably, the ceramic manufactured article 2 is a fired ceramic manufactured article.

It cannot however be ruled out from the scope of the present disclosure that the ceramic manufactured article 2 be a raw ceramic manufactured article.

Advantageously, the ceramic manufactured article 2 according to the present invention is a planar manufactured article having a first face 13 and a second face 14 opposite each other.

In detail, the ceramic manufactured article 2 comprises at least one main body and at least one covering layer.

According to the invention, the apparatus 1 comprises: a thermalization assembly 3 of a ceramic manufactured article 2 configured to allow the maintenance of the ceramic manufactured article itself at a predefined and constant temperature; and measurement means 4 for measuring the homogeneity of at least one of either the main body or the covering layer.

It is specified that in the context of the present disclosure, the expression “homogeneity” relates to a condition wherein the ceramic manufactured article 2 has the same mechanical and chemical/physical properties at every point, without having variations in density and porosity, is uniform and does not have residual mechanical stress.

In other words, the expression “homogeneity parameter” only relates to the mechanical and chemical/physical properties of the material, thus excluding aesthetic properties such as, e.g., the surface characterization of the ceramic manufactured article 2 or the dimensional characterization of the ceramic manufactured article 2 such as, e.g., the thickness of the latter.

Preferably, the homogeneity parameter comprises at least one value of residual mechanical stress of the ceramic manufactured article 2.

Advantageously, the homogeneity parameter consists in the value of residual mechanical stress.

The thermalization assembly 3 comprises supporting means 6, 15 of the ceramic manufactured article 2. According to a first preferred embodiment of the apparatus 1 , shown in Figures 1-3, the supporting means 6, 15 comprise at least one contact surface 6 of the ceramic manufactured article 2.

According to the aforementioned preferred embodiment of the apparatus 1 , the contact surface 6 is arranged inferiorly to the ceramic manufactured article 2 and is adapted to support it.

It cannot be ruled out from the scope of the present treatise that the contact surface be arranged superiorly to the ceramic manufactured article 2.

In detail, the contact surface 6 is arranged horizontally.

As can be seen in Figures 1-3, the ceramic manufactured article 2 has the second face 14 arranged in contact resting on the contact surface 6.

It cannot also be ruled out that the first face 13 be in contact with the contact surface 6.

It is specified that in the context of the present disclosure, expressions such as “high”, “low”, “upper”, “lower”, “above”, “below”, “horizontal” or “vertical” and the like, are to be considered with reference to an operative configuration wherein the contact surface 6 is parallel to the ground and supporting the ceramic manufactured article 2.

Furthermore, the contact surface 6 is made at least partly of a thermally conductive material, such as e.g. a metal alloy.

Preferably, the aforementioned conductive material is selected from stainless steel, brass and bronze.

Advantageously, the aforementioned conductive material is stainless steel.

It cannot however be ruled out from the scope of the present disclosure that the contact surface 6 be made of a poorly conductive material, such as e.g. ceramic, wood, marble or granite material.

In addition, it cannot however be ruled out from the scope of the present disclosure that the contact surface 6 have at least one surface protection layer.

Such a protection layer is obtained, e.g., by painting, phosphating or electrodeposition.

The protection layer is adapted to allow the protection of the contact surface 6 without, however, affecting the operation of the apparatus 1, in this case the homogeneity measurement of the ceramic manufactured article 2.

As can be seen in the figures, the contact surface 6 may have different surface areas.

In fact, according to a preferred embodiment shown in Figure 1, the contact surface 6 has a larger surface area than the surface area of the ceramic manufactured article 2.

Alternatively, as can be seen in Figure 2, the contact surface 6 has a smaller surface area than the surface area of the ceramic manufactured article 2.

Furthermore, as can be seen in Figure 3, the ceramic manufactured article 2 is resting on two contact surfaces 6 spaced apart from each other.

In this regard, it cannot be ruled out from the scope of the present disclosure that the apparatus 1 comprise a plurality of contact surfaces 6 adapted to support the ceramic manufactured article 2 at the point where different portions of the latter are located.

At the same time, according to a second embodiment of the apparatus 1 according to the invention, the supporting means 6, 15 comprise at least one holding element 15 which is configured to allow positioning the ceramic manufactured article 2 in suspension.

For example, the aforementioned holding element 15 is of the type of a clamp which can be associated with one side of the ceramic manufactured article 2, or alternatively, is of the type of a suction cup element arranged at the point where one of either the first face 13 or the second face 14 of the ceramic manufactured article 2 is located.

As can be seen in Figure 4, the supporting means 6, 15 comprise two holding elements 15 of the ceramic manufactured article 2 arranged on opposite sides of the latter and configured to allow the ceramic manufactured article itself to remain suspended during the operation of the apparatus 1.

Furthermore, it is of the utmost importance that the measurement means 4 are positioned at the point where a thermalized portion of the ceramic manufactured article 2 is located. According to the first embodiment of the apparatus 1 , the measurement means 4 are positioned at the point where a thermalized portion of the ceramic manufactured article 2 is located, i.e., arranged at the contact surface 6.

In this regard, the measurement means 4 are adapted to detect the thermal properties of the ceramic manufactured article 2.

Advantageously, the measurement means 4 are adapted to detect at least one of the following thermal parameters PTR of the ceramic manufactured article: thermal conductivity, heat flow, thermal resistance, heat transfer coefficient, thermal transmittance, specific heat, Biot number, Nusselt number, R value and U value.

It is specified that the aforementioned thermal parameters PTR are parameters known to the industry engineer.

In detail, the measurement means 4 comprise at least one sensor element 7 adapted to detect at least one of the aforementioned thermal parameters PTR.

According to a preferred embodiment of the measurement means 4 (Figures 1- 3), the sensor element 7 contacts the ceramic manufactured article 2 at the point where a first portion of the ceramic manufactured article itself is located and, at the same time, the contact surface 6 contacts the ceramic manufactured article 2 at the point where a second portion opposite the first portion is located and aligned thereto.

It cannot be ruled out from the scope of the present disclosure that the measurement means 4 comprise a plurality of sensor elements 7 configured to detect a plurality of thermal parameters PTR at the point where a plurality of the aforementioned portions of the ceramic manufactured article 2 is located.

In other words, it cannot be ruled out from the scope of the present disclosure that the measurement means comprise two, three, four, five, etc. sensor elements 7, each configured to detect one of the aforementioned thermal parameters PTR.

This means, for example, that according to a preferred embodiment of the aforementioned measurement means 4, the latter comprise four sensor elements 7. In this case, the four sensor elements 7 are positioned on different portions of the ceramic manufactured article 2 and each of them is adapted to detect one of the aforementioned thermal parameters PTR.

In other words, each sensor element 7 detects a thermal parameter PTR other than the thermal parameters PTR detected by the other sensor elements 7.

As can be seen in Figures 1-3, the sensor means 7 are positioned in contact with the first face 13 of the ceramic manufactured article 2 and the contact surface 6 is positioned at the point where the second face 14 of the ceramic manufactured article itself is located.

It cannot however be ruled out from the scope of the present disclosure that the sensor means be placed at the point where the second face 14 of the ceramic manufactured article 2 is located and the contact surface 6 be arranged at the point where the first face 13 of the ceramic manufactured article itself is located.

It cannot however also be ruled out that the sensor element 7 comprise at least one optical device for the acquisition of the thermal parameters PTR.

Preferably, the optical acquisition device is of the type of a thermal imaging camera.

The detected thermal parameters PTR define a thermal map 5 of the ceramic manufactured article 2.

In detail, the detected thermal parameters PTR are processed in order to assess the residual mechanical stress of the ceramic manufactured article 2.

For this purpose, the apparatus 1 comprises at least one data processing unit 8 of the detected thermal parameters PTR.

The data processing unit 8 comprises storage means 9 of the detected thermal parameters PTR.

In addition, the data processing unit 8 comprises calculation means 10 operationally connected to the measurement means 4 and to the storage means 9 and configured to compare the detected thermal parameters PTR with at least one predefined thermal parameter PTP.

In detail, the calculation means 10 are configured to process the thermal map 5 of the ceramic manufactured article 2 depending on the detected thermal parameter PTR.

Furthermore, the data processing unit 8 comprises analysis means of the thermal map 5 configured to process the value of residual mechanical stress of the ceramic manufactured article 2 depending on the detected thermal parameters PTR.

Preferably, the apparatus 1 comprises data filing means 11 configured to store a plurality of predefined thermal parameters PTP.

Alternatively, the aforementioned thermal parameters PTP are stored in a storage unit outside the apparatus 1 and operationally connected to the calculation means 10.

The correlation between the thermal properties of the ceramic manufactured article 2 and the homogeneity of the same is processed by means of the calculation means 10 to define a plurality of resulting parameters.

The resulting parameters are defined by the following ISO standards:

ISO 3274 Surface Texture: Profile method - Nominal characteristics of contact (stylus) instruments;

ISO 4287 Surface texture: Rules and procedures for the assessment of surface texture;

ISO 4288 Surface texture: Profile method - Terms, definitions and surface texture parameters;

ISO 11562 Surface texture: Profile method - Metrological characteristics of phase correct filters;

ISO 16610-21 Filtration - Linear profile filters: Gaussian filters / ISO 16610-28 Filtration - profile filters - End effects;

ISO 13565-1 Surface texture: Profile method; Surfaces having stratified functional properties - Part 1: Filtering and general measurement conditions;

ISO 13565-2 Surface texture: Profile method; Surfaces having stratified functional properties - Part 2: Height characterization using the linear material ratio curve. In this regard, it should be specified that the contact surface 6 plays a fundamental role in performing the homogeneity measurement of the ceramic manufactured article 2.

In fact, in order to ensure the reproducibility and repeatability of the measurement, the ceramic manufactured article 2 must have a predefined and controlled temperature.

For this purpose, the thermalization assembly 3 comprises temperature adjusting means 12 of the ceramic manufactured article 2, wherein the temperature ranged from 1°C to 150°C.

In detail, the adjustment of the temperature 12 is done either in a passive mode or in an active mode.

In the first case, the temperature adjusting means 12 comprise a containment volume of the ceramic manufactured article 2 configured to allow dispersion of the heat of said ceramic manufactured article 2; this means that the heat is transferred from the ceramic manufactured article to the containment volume thus allowing the cooling of the ceramic manufactured article itself, or vice versa.

The containment volume is of the type, e.g., of a confined environment inside which the ceramic manufactured article 2 is arranged resting on the contact surface 6.

It cannot be ruled out from the scope of the present disclosure that the contact surface 6 coincide with the ground.

At the same time in the second case, preferably, the temperature adjusting means 12 comprise at least one of: electrical resistance, a laser beam, an infrared source, a Peltier cell and thermal fluids.

According to the first embodiment shown in Figures 1-3, the temperature adjusting means 12 are associated with the contact surface 6 and configured to transfer and/or subtract heat to/from the ceramic manufactured article 2 resting on the latter.

As can be seen in Figures 1-3, the temperature adjusting means 12 comprise at least one of either the electrical heating element or the Peltier cell, are io associated with the contact surface 6 and configured to transfer and/or subtract heat to/from the ceramic manufactured article 2 resting on the latter.

For example, the temperature adjusting means 12 comprise an electrical heating element associated with the contact surface 6 and adapted to heat and/or cool the ceramic manufactured article 2 to a predefined temperature.

Alternatively, the temperature adjusting means 12 consist of a Peltier cell associated with the contact surface 6 and configured to subtract heat from the latter and, consequently, from the ceramic manufactured article 2.

According to a second embodiment of the apparatus 1, the temperature adjusting means 12 comprise at least one of the laser beam, the infrared source and the thermal fluids and wherein the aforementioned temperature adjusting means 12 are configured to irradiate and/or immerse in the thermal fluids the ceramic manufactured article 2 transferring and/or subtracting heat to/from the latter.

It is specified that the expression “thermal fluid” relates indistinctly to a liquid or a gas.

The thermal fluid may, e.g., be a liquid of the water, glycol, chlorinated hydrocarbon and/or fluorinated hydrocarbon type.

For example, in the event of the temperature adjusting means 12 consisting of the thermal fluid, the latter is: circulating inside the contact surface 6 and adapted to heat and/or cool the contact surface itself and, therefore, the ceramic manufactured article 2 in contact with the latter; or dispensed by immersing the ceramic manufactured article 2 inside the thermal fluid itself.

Furthermore, it is specified that the circulation of the thermal fluid inside the contact surface 6 occurs by means of ducts, e.g., of the coil type, placed inside it.

Alternatively, as can be seen in Figure 4, the thermal fluid may be of the type of a heated and/or cooled gas which is dispensed by immersing the ceramic manufactured article 2 inside it (Figure 4). At the same time, in the event of the temperature adjusting means 12 consisting of the heating element, the Peltier cell or the thermal fluid circulating inside the contact surface 6, the latter itself defines a surface of thermal exchange with the ceramic manufactured article 2 in such a way as to ensure homogeneous heating and/or cooling over the entire contact surface itself.

Furthermore, alternatively, the temperature adjusting means 12 consist of a laser device or of an infrared source arranged above the contact surface 6 and adapted to heat and/or cool the latter and, consequently, the ceramic manufactured article 2.

Furthermore, the apparatus 1 comprises movement means, not shown in detail in the illustrations, adapted to allow the ceramic manufactured article 2 to be positioned on the contact surface 6.

The movement means comprise conveyor belts and/or suction cup elements which can be operated by means of pneumatic systems.

Before the detailed description of the operation of the present invention, it will be necessary to specify that the apparatus according to the present invention allows measuring the state of tension of the ceramic manufactured article 2 quite apart from the conformation of the latter, such as, for example, in the case of rough surfaces or surfaces with cavities.

The operation of the present invention is as follows.

By way of example, according to the first embodiment of the apparatus 1, the ceramic manufactured article 2 is positioned on the contact surface 6.

In the present case, the second face 14 of the ceramic manufactured article 2 contacts the contact surface 6.

At this point, the temperature adjusting means heat and/or cool the contact surface 6 resulting in the thermalization of the ceramic manufactured article 2. Depending on operational requirements, the temperature adjusting means 12 locally vary the temperature of at least one portion of the ceramic manufactured article 2 for a short period of time. This means that at least one portion of the ceramic manufactured article 2 is thermalized at a predefined temperature and only one or more portions thereof are brought to different temperatures so as to allow the thermal perturbation of the ceramic manufactured article itself and the detection of the thermal parameters PTR by the sensor means 7.

The sensor elements 7 contact the first face 13 of the ceramic manufactured article 2 and detect the thermal parameters PTR of the same.

The aforementioned thermal parameters PTR are sent to the data processing unit 8 which, by comparison with the predefined thermal parameters PTP stored by the data filing means 11, are processed by means of the calculation means 10 to define a parameter which appears characteristic of the state of tension of the ceramic manufactured article 2, i.e., of the residual mechanical stress.

In detail, against a plurality of thermal data PTR detected by each of the sensor elements 7, the corresponding resulting parameters generated by the calculation means 10 define the thermal map 5 of the ceramic manufactured article 2.

Afterwards, the analysis means of the thermal map 5 process the residual mechanical stress value which provides an index of the state of homogeneity of the ceramic manufactured article 2.

It has in practice been ascertained that the described invention achieves the intended objects.

The particular solution of providing for the use of sensor elements configured to detect the thermal parameters of a ceramic manufactured article allows elaborating a map of the thermal properties of the latter by monitoring the homogeneity of the same.

In detail, the homogeneity of the ceramic manufactured article is assessed depending on the residual mechanical stress detected on the basis of the analysis of the thermal map processed by the apparatus according to the invention.

Claims

1) Apparatus (1) for the non-destructive quality control of a ceramic manufactured article, comprising: a thermalization assembly (3) of a ceramic manufactured article (2) configured to allow the maintenance of said ceramic manufactured article (2) at a constant predefined temperature, said thermalization assembly comprising supporting means (6, 15) of said ceramic manufactured article (2); measurement means (4) for measuring at least one homogeneity parameter of said ceramic manufactured article (2); characterized by the fact that said measurement means (4) are adapted to detect at least one of the following thermal parameters (PTR) of said ceramic manufactured article (2): thermal conductivity, heat flow, thermal resistance, heat transfer coefficient, thermal transmittance, specific heat, Biot number, Nusselt number, R value and U value.

2) Apparatus (1) according to claim 1, characterized by the fact that said supporting means (6, 15) comprise at least one contact surface (6) of said ceramic manufactured article (2).

3) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said supporting means (6, 15) comprise at least one holding element (15) of said ceramic manufactured article (2).

4) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said thermalization assembly (3) comprises temperature adjusting means (12) of said ceramic manufactured article (2), said temperature ranging from 1°C to 150°C.

5) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said temperature adjusting means (12) comprise a containment volume of said ceramic manufactured article (2) configured to allow dispersion of the heat of said ceramic manufactured article (2).

6) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said containment volume comprises at least one confined environment inside which said contact surface (6) of said ceramic manufactured article (2) is arranged.

7) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said temperature adjusting means (12) comprise at least one of: electrical resistance, a laser beam, an infrared source, a Peltier cell and thermal fluids.

8) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said temperature adjusting means (12) comprise at least one of either said electrical resistance or said Peltier cell, said temperature adjusting means (12) being associated with said contact surface (6) and configured to transfer and/or subtract heat to/from said ceramic manufactured article (2) resting on the latter.

9) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said temperature adjusting means (12) comprise at least one of said laser beam, said infrared source and said thermal fluids, said temperature adjusting means (12) being configured to irradiate and/or immerse in said thermal fluids said ceramic manufactured article (2) transferring and/or subtracting heat to/from the latter.

10) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said ceramic manufactured article (2) comprises at least one main body and at least one covering layer, said measurement means (4) being configured to measure said homogeneity parameter of at least one of either said main body or said covering layer.

11) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said measurement means (4) comprise at least one sensor element (7) adapted to detect at least one of said thermal parameters (PTR).

12) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said at least one sensor element (7) contacts said ceramic manufactured article (2) at the point where a first portion of said ceramic manufactured article (2) is located and said contact surface (6) contacts said ceramic manufactured article (2) at the point where a second portion opposite said first portion is located and aligned thereto.

13) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said sensor element (7) comprises at least one optical device for the acquisition of said detected thermal parameters (PTR).

14) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that it comprises at least one data processing unit (8) provided with storage means (9) of said detected thermal parameters (PTR).

15) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said homogeneity parameter comprises at least one value of residual mechanical stress of said ceramic manufactured article (2).

16) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said data processing unit (8) comprises calculation means (10) operationally connected to said measurement means (4) and to said storage means (9) and configured to compare said detected thermal parameters (PTR) with at least one predefined thermal parameter (PTP).

17) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said calculation means (10) are configured to process a thermal map (5) of said ceramic manufactured article (2) depending on said detected thermal parameters (PTR).

18) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that said data processing unit (8) comprises analysis means of said thermal map (5) configured to process said value of residual mechanical stress of said ceramic manufactured article (2) depending on said detected thermal parameters (PTR).

19) Apparatus (1) according to one or more of the preceding claims, characterized by the fact that it comprises a plurality of said sensors (7) configured to detect a plurality of said thermal parameters (PTR) at the point where a plurality of said portions of said ceramic manufactured article (2) is located.

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