Machine and method for manufacturing three-dimensional articles by deposition of a plurality of layers of a material for additive manufacturing

Abstract

Machine (1 ) for manufacturing three-dimensional articles (M) by deposition of a plurality of layers (L) of a material for additive manufacturing, comprising at least one extruder device (2) for depositing layers (L), movement means (6) for moving the at least one extruder device (2), a computerized numerical control unit (8) for controlling the at least one extruder device (2) and movement means (6), means (14) for detecting a series of data regarding at least one operating parameter and at least one control computer (16) connected to the automatic detection means (14) and to the computerized numerical control unit (9) and comprising a first software (18). The automatic detection means (14) comprise at least one infrared thermal camera (20) configured to detect data regarding the temperature of the deposited layers (L). The first software (18) of the control computer (16) is configured to perform the processing of the data detected and to control and adjust the operation of the extruder device (2) and the movement means (6) for the deposition of a further layer (L) of material on top of the already deposited layer (L) of material.

Description

[0001] Machine and method for manufacturing three-dimensional articles by deposition of a plurality of layers of a material for additive manufacturing

[0002] The present invention relates to a machine for manufacturing three- dimensional articles by deposition of a plurality of layers of a material for additive manufacturing.

[0003] The invention also relates to a method for manufacturing three-dimensional articles by deposition of a plurality of layers of a material for additive manufacturing.

[0004] For some time industrial machines for manufacturing three-dimensional articles by deposition of a plurality of layers of a material for additive manufacturing have been known.

[0005] These machines are preferably of the numerical-control type with Cartesian or anthropomorphic movements and may also have large dimensions, depending on the type of three-dimensional article to be manufactured.

[0006] Generally the material used in the process for manufacturing three- dimensional articles is a material chosen from the group comprising acrylonitrile butadiene styrene (ABS), nylon, polycarbonates, polyether ether ketone (PEEK), polypropylene (PP) and polylactic acid (PLA), which may be reinforced with carbon fibre or glass fibre.

[0007] In a manner known per se, this material for additive manufacturing is designed to be heated, fused, extruded and deposited in superimposed layers, in accordance with a technology which is better known as fused deposition modelling.

[0008] For this purpose, the machines for deposition of the layers of thermoplastic material, also called machines for three-dimensional or 3D printing, comprise at least one extruder device.

[0009] The extruder device comprises in turn at least one extruder element provided with a nozzle and a pump designed to ensure a homogeneous and constant flow of thermoplastic material to the extruder element.

[0010] The extruder device is mounted on suitable movement structures or movement means designed to allow the movement thereof inside a working area.

[0011] The movement structures may comprise, for example, an anthropomorphic robot, at the end of which the extruder device is mounted. Alternatively, the movement means may also be of the Cartesian type and may comprise a beam slidably mounted on a pair of side shoulders and comprising a first carriage slidably mounted on the said beam.

[0012] In turn the extruder device is also movable with respect to the carriage along a direction perpendicular to a surface supporting the three-dimensional articles.

[0013] Generally, the support surface is arranged horizontally, namely parallel to the ground, and the extruder device is movable along the vertical direction perpendicular to the support surface.

[0014] One drawback of the machines described above consists in the difficulty of controlling and adjusting the operating conditions and the working parameters for deposition of the layers of material in real time during the manufacture of the three-dimensional articles.

[0015] This drawback may result in the formation of imperfections in the deposited layers of material, such as geometrical and / or dimensional divergencies, namely dimensions and / or geometries of the article different from those required, delamination, deformation and porosity and / or a reduction in the mechanical strength of the three-dimensional article.

[0016] In order to overcome at least partially these drawbacks, machines for manufacturing three-dimensional articles which comprise a closed-loop feedback control system for the deposition of the layers of material have been developed.

[0017] In particular, these machines may comprise one or more sensors associated with the extruder device and / or the means for movement thereof.

[0018] The sensors are configured to detect a series of predetermined data regarding working parameters relating to the deposition of the material, for example the flowrate, the speed and the temperature of the thermoplastic material output from the nozzle, the speed of displacement or translation of the extruder device and / or the dimensions of the layers of thermoplastic material deposited on the support surface.

[0019] Moreover, the sensors transmit the detected data to a control unit or controller which allows the almost instantaneous control and adjustment of the operating conditions of the extruder device, such as the speed of rotation of the pump and the speed of rotation of the screw of the extruder element or the relative speed of movement of the extruder device on the basis of the detected data.

[0020] Examples of machines of the type indicated above are described in the patents and in the patent applications US10377124, US10688719 and US2020 / 0276757. These solutions are not without certain drawbacks.

[0021] A first drawback consists in the fact that the closed-loop feedback control system operates with a certain delay in relation to the deposition of the layers of material.

[0022] This drawback is particularly significant in the case of large-size machines with extruder devices which have particularly high capacities for extrusion and deposition of the thermoplastic material.

[0023] Moreover, this drawback is particularly evident in the case where the speed of displacement of the extruder device must be kept at particularly high values or in the case where the portions of the three-dimensional article to be manufactured have small radii of curvature.

[0024] Therefore, these machines are unable to avoid completely the formation of imperfections or zones with low mechanical strength in some portions of the three-dimensional article.

[0025] Furthermore, the machines described above may be subject to further problems and drawbacks such as:

[0026] - slow material deposition speeds;

[0027] - greater amount of waste material during the material deposition process;

[0028] - increased production costs;

[0029] - smaller range of three-dimensional articles which can be manufactured, in particular articles with large dimensions or comprising portions with complex geometric forms.

[0030] In an attempt to overcome the aforementioned drawbacks, further machines have been developed, these involving the use of sensors and artificial intelligence in order to detect and process the data of working parameters relating to the deposition of the material and / or data relating to the geometrical and / or dimensional and / or qualitative and / or structural characteristics of the layers deposited during the manufacture of test samples so as to obtain optimized reference values of the working parameters.

[0031] These optimized reference values are such that the parts or the portions of the three-dimensional articles made are substantially devoid of deformations, geometrical and / or dimensional divergencies from the predetermined geometrical characteristics and / or zones with low mechanical strength.

[0032] An example of these machines for manufacturing three-dimensional articles is described in the patent application WO2023 / 089454.

[0033] In these improved machines it is also crucial to control the temperatures of the various superimposed layers during the process for manufacture of the three-dimensional articles, in order to favour their correct adhesion and ensure the stability thereof.

[0034] In fact the adhesion between the deposited layers of material is all the greater and more efficient the more the actual temperatures of the already deposited layers are close to predefined optimum temperatures at the moment when the following layers are deposited.

[0035] The optimum temperatures vary depending, for example, on the material used for additive manufacturing and the dimensional characteristics of the layers and lie within limited and well-defined ranges.

[0036] For example, if the actual temperature of a previously deposited layer is less than the optimum temperature, the adhesion of a further layer deposited subsequently is almost prevented or insufficient owing to the fact that the previously deposited layer has already hardened at the moment of deposition of the further layer.

[0037] On the other hand, if the actual temperature of a previously deposited layer is higher than the optimum temperature, this layer is pliable and soft and therefore does not ensure a stable support for the further layers which are deposited thereafter.

[0038] Among the sensors used in the machines for manufacturing three- dimensional articles by means of additive manufacturing there are also thermal cameras for detecting the temperature of the material of the layers.

[0039] Thermal cameras are generally mounted on a motorized structure, in turn fixed to the body of the at least one extruder device. The motorized structure is moved so as to orient the thermal camera in the direction of movement of the nozzle of the extruder device so that it is constantly directed towards the opposite-lying area of material onto which the further layer of material will be deposited.

[0040] Furthermore, the data relating to the temperature of the layers and detected by the thermal cameras is used immediately to adjust the process for deposition of the layers of material.

[0041] Some working parameters, such as the speed of movement of the at least one extruder device and the flowrate of the material, may be adjusted depending on the temperature data detected.

[0042] A first drawback arising from the use of these latter technical solutions lies in the fact that the adjustment of the aforementioned working parameters is performed a posteriori and in a simplistic manner, so that it is difficult to deposit the layers of material with temperatures close to the optimum temperatures.

[0043] This drawback has the consequence that the reduction of the deformations or the defects affecting the three-dimensional articles is limited. Furthermore, this drawback may result in the so-called “oscillating” effect, where the temperatures of the materials of the layers oscillate between values higher and lower than the optimum temperatures.

[0044] A further drawback of these latter technical solutions is that control of the movement of the thermal camera, namely of the motorized structure, is particularly complex and costly.

[0045] The main object of the present invention is to provide a machine and a method for manufacturing three-dimensional articles by means of deposition of a plurality of layers of a material for additive manufacturing, which are able to solve the drawbacks indicated above.

[0046] A particular task of the present invention is to provide a machine and a method of the type described above which ensure strong and efficient adhesion between the layers of material.

[0047] Another task of the present invention is to provide a machine and a method of the type described above which ensure the stability of the subsequently deposited layers of material.

[0048] A further task of the present invention is to provide a machine and a method of the type described above which are able to prevent the formation of imperfections and defects in the deposited layers of material and in the three- dimensional articles thus made.

[0049] Another task of the present invention is to provide a machine of the type described above which has lower management costs and is simpler than the machines known in the sector.

[0050] The object and the main tasks described above are achieved with a machine for manufacturing three-dimensional articles according to Claim 1 and with a method for manufacturing three-dimensional articles according to Claim 15.

[0051] In order to illustrate more clearly the innovative principles of the present invention and its advantages compared to the prior art, an example of embodiment of a machine for manufacturing three-dimensional articles according to the present invention will be described below with the aid of the attached drawings. In particular:

[0052] - Figure 1 is a perspective view of a machine for manufacturing three- dimensional articles according to the present invention;

[0053] - Figure 2 is a perspective view, on larger scale, of a detail of Figure 1 ;

[0054] - Figure 3 is a perspective view, on a larger scale, of a detail of the machine for manufacturing three-dimensional articles, in which means for automatically detecting a series of data regarding at least one working parameter are visible;

[0055] - Figure 4 is a perspective view of a detail of the machine for manufacturing three-dimensional articles according to Figure 1 ;

[0056] - Figure 5 is a front view of the detail of the machine according to Figure 4;

[0057] - Figure 6 is a schematic / functional view of the machine for manufacturing three-dimensional articles according to the present invention;

[0058] The present invention, provided solely by way of a non-limiting illustration of the scope of prevention of the invention, relates to a machine and a method for manufacturing three-dimensional articles by means of deposition of a plurality of layers of a material for additive manufacturing.

[0059] With particular reference to Figure 1 and the schematic view of Figure 6, the machine is indicated overall by the reference number 1 .

[0060] In the continuation of the present description reference will be made mainly to a thermoplastic material such as material for additive manufacturing of articles.

[0061] For example, the thermoplastic material for additive manufacturing according to the present invention may be a thermoplastic material such as polyetherimide, acrylonitrile butadiene styrene (ABS), nylon, polycarbonate, polyether ether ketone (PEEK), polypropylene (PP) and polylactic acid (PLA), which may be reinforced with carbon fibre or fibre glass.

[0062] However, the material may be chosen from within the group which comprises composite materials, ceramic materials, metallic materials and concrete.

[0063] In a manner known per se, the material is deposited in the form layers L which are preferably superimposed or adjoining; the layers L may be deposited in a variable number and with variable dimensions depending on the type of article to be manufactured.

[0064] The three-dimensional article M may have different forms, dimensions and profiles and comprise portions or parts with predetermined geometrical characteristics also different from the characteristics shown in Figures 1 -3.

[0065] The geometrical characteristics of the portions of the article M may be chosen from the group comprising the form, ramps, radii of curvature, widths and thicknesses of the deposited layers L of material, the superimposition of different or adjoining portions, the interspaces between adjoining portions.

[0066] For example, the portions of the article M may consist of curved sections with different radii of curvature, straight sections, portions with different thicknesses of the deposited layers L of material, ramps with different inclinations, portions with different widths of the layers L of deposited material, adjacent portions. The machine 1 according to the present invention comprises:

[0067] - at least one extruder device 2 with a nozzle 4 for depositing layers L of material within an actual time range;

[0068] - movement means 6 for moving the at least one extruder device 2;

[0069] - a surface 5 for supporting the articles M to be made;

[0070] - a computerized numerical control (CNC) unit or PLC 8 having dedicated software 12 for controlling the at least one extruder device 2 and the movement means 6;

[0071] - means 14 for detecting a series of data regarding at least one operating or working parameter relating to the deposition of the layers L of material;

[0072] - at least one control computer 16 connected to the automatic detection means 14 and to the computerized numerical control unit 8 and comprising a first software 18 configured at least to collect and process the data detected by the automatic detection means 14.

[0073] In addition to the nozzle 4, the at least one extruder device 2 comprises at least one screw extruder element and a pump, not visible in the attached figures.

[0074] The at least one extruder device 2 may comprise the support structure 11 shown in Figures 4 and 5, which may also be different, without thereby departing from the scope of protection of the present invention.

[0075] As shown in Figures 1 and 3, the movement means 6 are preferably of the Cartesian type, namely they comprise, for example, a carriage 13 mounted slidably on a beam 7 mounted also slidably on a pair of side shoulders 9.

[0076] The at least one extruder device 2 is movable within the space situated above the support surface 5 for the articles M to be made, by means of the movement means 6 so that it can be positioned at any point thereon.

[0077] Furthermore, the movement means 6 are configured to move the at least one extruder device 2 along a direction perpendicular to the support surface 5, so as to adjust the distance of the nozzle 4 from the support surface 5.

[0078] Alternatively the movement means may be of the anthropomorphic type, namely comprise a robotic arm.

[0079] The computerized numerical control unit 8, shown schematically in Figure 6, is configured mainly to control the extrusion flowrate of the material of the at least one extruder device 2 and the speed of displacement of the movement means 6.

[0080] In particular, the computerized numerical control unit 8 is configured to adjust the operation of the at least one extruder device 2 and the movement means 6 based on a working program or setup which contains specific predefined working parameters for the deposition of each of the layers L of material.

[0081] These values of the working parameters are processed depending on the characteristics of the article M to be manufactured and may comprise the actual deposition time of each layer, the speed and the deposition flowrate of the material, the trajectory of the at least one extruder device 2 moved by the movement means 6 and the speed of the movement means 6.

[0082] The at least one control computer 16, which is also schematically shown in Figure 6, preferably consists of an industrial personal computer located preferably on the machine.

[0083] In accordance with the present invention, the automatic detection means 14 comprise at least one infrared thermal camera 20 configured to detect data relating to the temperature of the deposited layers L of material. The temperature of the layers of material therefore represents the operating or working parameter indicated above with reference to the automatic detection means 14.

[0084] The at least one thermal camera 20 is shown in the detail of Figures 3-5 with reference to the at least one extruder device 2 and schematically shown in Figure 6.

[0085] The at least one infrared thermal camera 20 is mounted on the body 3 of the at least one extruder device 2 so as to be fixed during the process for deposition of the layers L of material. However, the thermal camera 20 may be adjusted manually by an operator before the process for deposition of the layers L of material.

[0086] This option is made possible by a particular configuration of the first software 18 of the at least one control computer 16, described below, which allows the management of the at least one thermal camera 20 to be simplified in terms of both costs and complexity compared to the prior art.

[0087] In a manner known per se, the data relating to the temperature of the deposited layers L is collected by the at least one infrared thermal camera 20 in the form of images or thermal images consisting of a grid formed by a plurality of pixels, each of which corresponds to the temperature value of a specific area of the deposited layer L of material.

[0088] In accordance with an alternative embodiment, not shown in the attached figures, the machine 1 for manufacturing three-dimensional articles M may also comprise a pair of thermal cameras 20 which are mounted fixed on the body 3 of the extruder device 2.

[0089] Furthermore, the first software 18 of the at least one control computer 16 is configured to perform the processing of the data detected by the at least one infrared thermal camera 20 and regarding the temperature of a layer L of material already deposited and to control and adjust the operation of the at least one extruder device 2 and the movement means 6 for deposition of a further layer L of material on top of the already deposited layer L of material.

[0090] In particular the first software 18 of the at least one control computer 16 is configured to:

[0091] - determine a posteriori, based on the processing of the temperature data detected, an optimum deposition time range of the already deposited layer L of material;

[0092] - make a comparison between the actual time range contained in the working program and used by the machine 1 and the optimum time range determined a posteriori; and

[0093] - adjust consequently the operation of the at least one extruder device 2 and the movement means 6 for deposition of a further successive layer L of material.

[0094] This adjustment is performed on the computerized numerical control unit 8 of the machine 1 based on the comparison of the ranges of the actual time taken and of the predetermined optimum time.

[0095] In the present description, the expression “optimum time range” is understood as meaning a time range in which the deposition of a layer L of material is performed in such a way that this layer has an optimum temperature, namely a temperature close to the temperature such that the adhesion with a further layer to be subsequently deposited is strong and effective, ensuring a good bonding action between the superimposed layers of material. For example, the optimum temperature of the polyetherimide is close to 240 °C and the optimum temperature of the acrylonitrile butadiene styrene is close to 140 °C.

[0096] In the first case, the first software 18 is able, for example, to determine a range of about + / - 10 °C, while in the second case the first software 18 is able, for example, to determine a range of about + / - 7.5 °C .

[0097] With reference to that stated above, the at least one control computer 16 is configured to adjust and correct mainly the actual deposition time of the further successive layer, the extrusion flowrate of the material of the at least one extruder device 2 and the speed of displacement of the movement means 6 after making a comparison between the actual time range and the optimum time range with reference to the already deposited layer.

[0098] From that stated above it may be noted that the first software 18 of the at least one control computer 16 intervenes to correct the values of at least some of the working parameters contained in the working program.

[0099] The trajectory to be followed by the at least one extruder device 2 remains fixed and is not intended to be adjusted based on the processing performed by the first software 18.

[0100] In this way, by means of adjustment of the actual deposition time of the further successive layer it is possible to obtain optimum adhesion of the further layer with respect to the already deposited layer.

[0101] Furthermore, the first software 18 of the at least one control computer 16 may be configured to select a predefined pixel of the grid of the image detected by the thermal camera 20.

[0102] In particular, the first software 18 of the at least one control computer 16 is configured to select the pixel of the grid corresponding to the area of the already deposited layer L of material situated opposite the nozzle 4 based on the determination of the trajectory, the position and the orientation of the nozzle 4 by the computerized numerical control unit 8.

[0103] Operationally speaking, the at least one infrared thermal camera 20, with the aid of the first software 18, detects the temperature of the already deposited layer L of material at a plurality of points or positions established by the computerized numerical control unit 8, selecting for each point or position a predefined pixel on the grid of the image, preferably the pixel which corresponds to the area of the already deposited layer L of material situated opposite the nozzle 4.

[0104] The first software 18 of the at least one control computer 16 is configured to calculate the average temperature of the already deposited layer L based on the temperatures detected for the various points or positions of the layer L.

[0105] The average temperature of the already deposited layer L is then used to process and determine the optimum deposition time range, as described above.

[0106] The machine 1 may also comprise a predictive and / or thermodynamic software model configured to carry out a regression analysis based on temperature data and on data regarding the deposition times of the layers L of material so as to obtain corresponding regression models or curves.

[0107] Said data regarding the temperatures of the layers L and their deposition times may be obtained by means of the execution of test deposition processes which use the machine 1 according to the present invention and may be stored in a storage device or in a cloud system. Each regression model is specific for a particular type of article having specific characteristics regarding the material for the additive manufacturing, the form, the dimensions, the thermal characteristics, etc.

[0108] Moreover, each regression model is obtained considering:

[0109] - one or more operating conditions of the process for the deposition of the layer of material, such as the trajectory of the path for deposition of the layers L of material followed by at least one extruder device 2, the dimensions of the cross-section of the layers L of material and the environmental conditions;

[0110] - the material used for additive manufacturing and therefore one or more characteristics of the material such as the specific heat of the material and the heat exchange coefficients;

[0111] - the shape and the dimensions of the article M to be made by means of deposition of the layers L.

[0112] Conveniently, the first software 18 of the at least one control computer 16 is configured to determine the optimum time range for deposition of the already deposited layer L, as indicated above, based on a specific regression model obtained by means of the predictive software model.

[0113] In particular, the first software 18 of the at least one control computer 16 may be configured to determine the optimum time range based on a specific regression model obtained by means of the predictive software model and the comparison between the detected temperature data of the already deposited layer L and the optimum temperature value.

[0114] Moreover, the predictive software model may be implemented on a second software 22 of a further control computer 24 connected to the computerized numerical control unit 8, as shown schematically in Figure 6. Preferably, the second software 22 may be based on at least one artificial intelligence algorithm.

[0115] The further computer 24 with the second software 22 is connected, preferably remotely, to the computerized numerical control unit 8.

[0116] Operationally speaking, the further control computer 24 is configured to transmit the regression models described above to the computerized numerical control unit 8, as shown schematically in Figure 6, so that these regression models are subsequently transmitted to the first software 18 of the at least one control computer 16 during the process for deposition of the layers L of material.

[0117] Advantageously, the further control computer 24 with the second software 22 may be considered as corresponding to the processing unit with a software based on at least one artificial intelligence algorithm described in WO2023 / 089454.

[0118] In this respect it is pointed out that the predictive software model and / or the second software 22 of the further control computer 24 may also be configured to process optimized reference values of the working parameters and to transmit the optimized reference values to the computerized numerical control unit 8 so that the deposition process is performed on the basis of these optimized reference values for each of the layers L.

[0119] With reference to that described above, the optimized reference values of the working parameters are implemented in the working program intended to be loaded in the computerized numerical control unit 8.

[0120] In particular, the optimized reference values are:

[0121] - obtained based on the processing of data regarding working parameters relating to the deposition of the layers L and / or data regarding the geometrical and / or dimensional and / or qualitative and / or structural characteristics of the deposited layers L detected by means of further automatic detection means, not shown in the attached figures.

[0122] - used during the process for deposition of the layers L of material in order to obtain parts or portions of the three-dimensional article M which are devoid or substantially devoid of deformations, geometrical and / or dimensional divergencies from the predetermined geometrical characteristics, or porosity and / or zones with low mechanical strength.

[0123] The data regarding working parameters relating to the deposition of the layers L and / or data regarding geometrical and / or dimensional and / or qualitative and / or structural characteristics of the deposited layers L may be detected during the manufacture of test samples and stored in a suitable storage device or in a cloud system.

[0124] As mentioned, the present invention relates also to a method for manufacturing three-dimensional articles M by means of deposition of a plurality of layers L of a material for additive manufacturing by means of at least one extruder device 2 provided with a nozzle 4 and movement means 6 for moving the at least one extruder device 2, of the type described above with reference to the machine 1 .

[0125] The method comprises preferably the following steps:

[0126] - deposition of a layer L of material for additive manufacturing by means of at least one extruder device 2 within an actual time range;

[0127] - automatic detection of a series of data regarding at least one working parameter related to the deposited layer L; - deposition of a further successive layer L of material for additive manufacturing on top of said already deposited layer L.

[0128] In accordance with the present invention, the automatic detection step is performed by means of at least one infrared thermal camera 20 configured to detect data regarding the temperature of the already deposited layers L.

[0129] Preferably, the at least one thermal camera 20 is fixed with respect to the body 3 of the at least one extruder device 2 during the steps for deposition of the layers L of material.

[0130] The detected data regarding the temperature of the already deposited layer L is recorded by the at least one infrared thermal camera 20 in the form of images or thermal images consisting of a grid formed by a plurality pixels, each of which corresponds to the temperature value of a specific area of the deposited layer L of material.

[0131] Moreover, the method comprises a step of processing at least the detected data relating to the temperature of the already deposited layer L of material in order to adjust the step of deposition of the further successive layer L of material on top of the already deposited layer L.

[0132] The temperature data detection step and the processing step are repeated for each of the layers L of material so as to obtain in any case the optimum adhesion of the layer deposited subsequently onto the already deposited layer.

[0133] Advantageously, the step of processing the detected data regarding the temperature is performed preferably in order to determine an optimum deposition time range of the already deposited layer L.

[0134] Furthermore, the method preferably comprises a step of comparing the actual deposition time range, loaded in the working program and used by the machine, and the optimum deposition time range of the already deposited layer L in order to adjust the step for deposition of the further successive layer L of material on top of the already deposited layer L.

[0135] The at least one extruder device 2 and the movement means 6 of the at least one extruder device 2 are controlled by means of the computerized numerical control unit 8 of the machine 1 described above.

[0136] The step of processing the data regarding the temperature of the material of the deposited layer L is performed by means of the first software 18 of the at least one control computer 16 of the machine 1 described above.

[0137] The at least one control computer 16 with the first software 18 is configured to adjust the step of deposition of the further successive layer L of material acting on the computerized numerical control unit 8 of the machine 1 , using the methods described above, so as to obtain optimum adhesion between the various superimposed layers.

[0138] The method may also envisage the use of a predictive and / or thermodynamic software model, of the type indicated above with reference to the machine 1 , and configured to carry out a regression analysis based on temperature data and data regarding the deposition times of the layers of material so as to obtain a corresponding regression model or curve.

[0139] Each regression model is specific for each type of article to be manufactured and is calculated using the methods described above with reference to the machine.

[0140] The first software 18 of the at least one control computer 16 may use a specific regression model obtained by means of the predictive software model in order to determine the optimum time range of the already deposited layer of material.

[0141] Furthermore, the first software 18 of the at least one control computer 16 is configured to determine the optimum time range based on the specific regression model obtained by means of the predictive software model and the comparison between the detected temperature data of the already deposited layer L and the optimum temperature value.

[0142] The method may also comprise a step, to be performed at the same time as the step for deposition of each layer L of material, for selecting a predefined pixel of the grid of the image recorded by the thermal camera 20 and detecting the corresponding temperature.

[0143] This step is performed by the first software 18 of the at least one control computer 16 based on the trajectory, position and orientation of the at least one extruder device determined by the computerized numerical control unit 8 of the machine 1 .

[0144] In particular, the first software 18 of the at least one control computer 16 is configured to select the pixel of the grid corresponding to the area of the already deposited layer of material situated opposite the nozzle 4 of the at least one extruder device 2.

[0145] From the above description it is now clear how the machine and the method for manufacturing three-dimensional articles according to the present invention are able to achieve advantageously the predefined objects.

[0146] In particular, by means of the use of at least one infrared thermal camera in combination with the first software, the predictive software model and the second software, it is possible to deposit the further layers of material onto the already deposited layers when the temperature of the latter is close to the predetermined optimum temperature for each type of material.

[0147] This measure is able to favour the adhesion between the deposited layers of material, ensuring the stability of the further layers of material deposited subsequently.

Claims

Claims1. Machine (1 ) for manufacturing three-dimensional articles (M) by deposition of a plurality of layers (L) of a material for additive manufacturing, comprising:- at least one extruder device (2) with a nozzle (4) for depositing layers (L) of material within an actual time range;- movement means (6) for moving the at least one extruder device (2);- a computerized numerical control unit (8) for controlling said at least one extruder device (2) and said movement means (6);- means (14) for detecting a series of data regarding at least one operating parameter relating to the deposition of the layers (L) of material;- at least one control computer (16) connected to said automatic detection means (14) and to said computerized numerical control unit (8) and comprising a first software (18); characterized in that said automatic detection means (14) comprise at least one infrared thermal camera (20) configured to detect data regarding the temperature of the deposited layers (L) of material, the first software (18) of said at least one control computer (16) being configured to perform the processing of the data regarding the temperature of an already deposited layer (L) of material and to adjust the operation of said at least one extruder device (2) and of said movement means (6) for the deposition of a further successive layer (L) of material on top of the already deposited layer (L) of material.

2. Machine (1 ) according to the preceding claim, characterized in thatthe first software (18) of said at least one control computer (16) is configured to determine a posteriori, based on the processing of the detected temperature data, an optimum deposition time range of the already deposited layer (L) of material.

3. Machine (1 ) according to the preceding claim, characterized in that the first software (18) of said at least one control computer (16) is configured to make a comparison between the actual deposition time range used by the machine and the optimum deposition time range of the already deposited layer (L) of material and to adjust consequently the operation of said at least one extruder device (2) and said movement means (6) for depositing a further successive layer (L) of material acting on said computerized numerical control unit (8).

4. Machine (1 ) according to either one of Claims 2-3, characterized in that it comprises a predictive software model configured to carry out a regression analysis based on temperature data and on data regarding the deposition times of the layers (L) of material so as to obtain a corresponding regression model.

5. Machine (1 ) according to the preceding claim, characterized in that said predictive model is implemented on a second software (22) of a further control computer (24) connected to said computerized numerical control unit (8), said second software (22) being based on at least one artificial intelligence algorithm.

6. Machine (1 ) according to either one of Claims 4 and 5, characterized in that said first software (18) of said at least one control computer (16) is configured to determine the optimum deposition time range of the alreadydeposited layer (L) based on a specific regression model obtained by means of the predictive software model.

7. Machine (1 ) according to any one of Claims 4 to 6, characterized in that said first software (18) of said at least one control computer (16) is configured to determine the optimum time range based on a specific regression model obtained by means of the predictive software model and on the comparison between the detected temperature data of an already deposited layer (L) and an optimum temperature value.

8. Machine (1 ) according to any one of Claims 4 to 7, characterized in that said predictive software model and / or said second software (22) of said further control computer (24) are configured to process optimized reference values of working parameters and to transmit the optimized reference values to the computerized numerical control unit (8).

9. Machine (1 ) according to the preceding claim, characterized in that said optimized reference values are obtained based on the processing of data regarding working parameters relating to the deposition of the layers (L) and / or data regarding geometrical and / or dimensional and / or qualitative and / or structural characteristics of the deposited layers (L).

10. Machine (1 ) according to any one of the preceding claims, characterized in that the computerized numerical control unit (8) is configured to adjust the operation of at least one extruder device (2) and of said movement means (6) based on a working program containing predefined values of working parameters, such as the actual deposition time of each layer (L), the speed and the flowrate of deposition of the material, the trajectory of the at least one extruder device (2) and the speed of themovement means (6), said first software (18) of said at least on control computer (16) being configured to adjust and correct the values of at least some working parameters of the working program.

11. Machine (1 ) according to the preceding claim, where dependent on either one of Claims 8 and 9, characterized in that the optimized reference values of the working parameters are implemented in the working program.

12. Machine (1 ) according to any one of the preceding claims, characterized in that said at least one infrared thermal camera (20) is fixed with respect to the body (3) of said at least one extruder device (2) during the process for deposition of the layers (L) of material.

13. Machine (1 ) according to the preceding claim, characterized in that the data regarding the temperature of the deposited layers (L) is recorded by said at least one infrared thermal camera (20) in the form of images consisting of a grid formed by a plurality of pixels each of which corresponds to the temperature value of a specific area of the deposited layer (L) of material, the first software (18) of said at least one control computer (16) being configured to select a predefined pixel of the grid and to detect the corresponding temperature on the basis of the trajectory, the position and the orientation of the nozzle (4) of the at least one extruder device (2) which are determined by the computerized numerical control unit (8).

14. Machine (1 ) according to the preceding claim, characterized in that the first software (18) of said at least one control computer (16) is configured to select the pixel of the grid corresponding to the area of the already deposited layer (L) of material situated opposite the nozzle (4).

15. Method for manufacturing three-dimensional articles (M) bydepositing a plurality of layers (L) of a material for additive manufacturing by means of at least one extruder device (2) provided with a nozzle (4) and movement means (6) for moving the at least one extruder device (2), which method comprises the following steps:- deposition of a layer (L) of material for additive manufacturing by means of said at least one extruder device (2) within an actual time range;- automatic detection of a series of data regarding at least one operating parameter relating to the deposited layer (L);- deposition of a further successive layer (L) of material for additive manufacturing on top of said already deposited layer (L); characterized in that said automatic detection step is performed by means of at least one infrared thermal camera (20) configured to detect data regarding the temperature of the already deposited layers (L) of material, there being provided a step for processing at least said detected data regarding the temperature of an already deposited layer (L) of material in order to regulate the step of deposition of a further successive layer (L) of material on top of the already deposited layer (L).

16. Method according to the preceding claim, characterized in that said step of processing the detected data regarding the temperature is performed so as to determine a posteriori an optimum deposition time range of the already deposited layer (L).

17. Method according to the preceding claim, characterized in that it comprises a step of comparing the actual time range used during the step for deposition of said already deposited layer (L) and the optimum deposition time range determined for the already deposited layer (L) so as to adjust saidstep for deposition of the further successive layer (L) of material on top of said already deposited layer (L).

18. Method according to the preceding claim, characterized in that said at least one extruder device (2) and said movement means (6) are controlled by a computerized numerical control unit (8), said step for processing the detected data regarding the temperature being performed by means of a first software (18) of at least one control computer (16) configured to adjust said step for deposition of the further successive layer (L) of material acting on said computerized numerical control unit (8).

19. Method according to any one of Claims 15 to 17, characterized in that it involves the use of a predictive software model configured to carry out a regression analysis based on temperature data and on data regarding the deposition times of the layers (L) of material so as to obtain a corresponding regression model.

20. Method according to the preceding claim, where dependent on Claim 16, characterized in that the first software (18) of said at least one control computer (16) is configured to determine the optimum deposition time range of the already deposited layer (L) based on a specific regression model obtained by means of said predictive software model.

21. Method according to the preceding claim, characterized in that the first software (18) of said at least one control computer (16) is configured to determine the optimum time range based on a specific regression model obtained by means of the predictive software model and on the comparison between the detected temperature data of an already deposited layer (L) and an optimum temperature value.

22. Method according to any one of Claims 15-21 , characterized in that said at least one infrared thermal camera (20) is fixed with respect to the body (3) of said at least one extruder device (2) during the deposition of the layers (L) of material.

23. Method according to the preceding claim, where dependent on Claim 18, characterized in that the detected data regarding the temperature of the already deposited layer (L) is recorded by said at least one infrared thermal camera (20) in the form of an image consisting of a grid formed by a plurality of pixels each of which corresponds to the temperature value of a specific area of the deposited layer (L) of material, there being provided a step for selecting a predefined pixel of the grid and detecting the corresponding temperature performed by said first software (18) on the basis of the trajectory, the position and the orientation of the at least one extruder device (2) which are determined by the computerized numerical control unit (8).

24. Method according to the preceding claim, characterized in that the first software (18) of said at least one control computer (16) is configured to select the pixel of said grid corresponding to the area of the already deposited layer of material situated opposite the nozzle (4) of the at least one extruder device (2).

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