Method for integrating sensor into component fabricated by additive manufacturing

Abstract

To find a sensor that can resist additional manufacturing methods, such as high temperature, mechanical stress, and high laser density, and / or to minimize its degradation to obtain good measurement performance during and after integration.SOLUTION: The present invention relates to a method for integrating a sensor into a metal component, comprising the steps of: a) creating, by an additive printing, a first part (2) of the component including a volume (4) for housing the sensor, the volume having a width larger than the sensor; b) depositing the sensor in the housing volume (4); and c) creating, by additive printing, a second part (6) of the component covering the sensor, thereby forming melt paddles in the housing volume (4) on both side of the sensor.SELECTED DRAWING: Figure 1C

Description

[Technical Field]

[0001] The present invention relates to the field of advanced metrology of mechanical parts, especially those coming from additive manufacturing, with the aim of performing integrated RT-SHM (Real Time Structural Health Monitoring). [Background technology]

[0002] During the printing procedure, it is desired to measure such parts by integrating sensors, preferably optical fibers, which make it possible to measure at least one parameter such as temperature, deformation, stress, vibration or amount of radiation.

[0003] Firstly, this integration allows online monitoring of the stresses and / or temperatures applied on the machine parts during production in order to control and optimize the printing process, and secondly, it allows monitoring the wear and potential degradation of the systems in which these parts are integrated, during their use as primary or secondary components, making it possible to anticipate any failures and improve the management and replacement of these parts or other components of the system, and to create a predictive maintenance thereof.

[0004] On this subject, the articles "A Review of Distributed Optical Fiber Sensors for Civil Engineering Applications" by A. Barrias et al., Sensors, vol. 16, no. 5, 2016, doi: 10.3390 / s1605074818, or "Qualification and Calibration of Single-Mode Phosphosilicate Optical Fiber for Dosimetry at CERN" by D.D. Francesca et al., J. Lightwave Technol., vol. 37, no. 18, pp. 4643-4649, September 2019, are known.

[0005] Currently, the sensors used are placed outside the component and exposed to external stresses (environment, influences...), but these sensors can only measure the outside of the component and not the inside, so it is very difficult to know the internal behavior of the structure without using approximation and extrapolation models.

[0006] The integration of sensors, especially optical fibers, inside components is possible through metal additive manufacturing, which makes it possible to eliminate the need for traditional measurement techniques, since the sensor measures its own physical quantity, which is the same as the target part.

[0007] Such integration of the sensor also makes it possible to protect it from the operating environment of the component in which it is placed and to reduce the volume created by conventional surface sensors.

[0008] However, integrating sensors through additive manufacturing is very complex. One well-known integration technique is described in the paper by Stoll, P. et al. entitled "Embedding fiber optical sensors into SLM parts" in the 27th Annual International Solid Freeform Fabrication Symposium, pp. 1815-1825 (2016). However, the printing stresses strongly degrade the sensors, often leading to their destruction.

[0009] Another known solution involves protecting the fiber sensor (such as a Bragg network) with a dense layer of material such as chromium / nickel. On this subject, see in particular the article by Dirk Haverman et al. entitled "Embedding optical fibers into stainless steel using laser additive manufacturing", ICALEO 2013, 381 (2013), doi: 10.2351 / 1.5062904.

[0010] These known solutions are complex, their implementation is costly, they involve high isolation of the sensor (fiber) with respect to the measurement environment, and they therefore introduce significant measurement errors.

[0011] One challenge that arises is therefore to find a sensor that can withstand the additive manufacturing methods (high temperatures, mechanical stress, high laser densities...) and / or minimize its degradation in order to obtain good measurement performance during and after integration.

[0012] Another challenge is the optimization of the parameters of the method for integrating such sensors, especially if additive printing techniques are implemented, such as the scanning speed and direction, and / or the laser power, and / or the integration geometry, i.e. the shape of the part where the fiber will be placed before integration (semicircle, rectangle...).

[0013] A further challenge lies in the selection, adaptation and optimization of the sensors and of the corresponding measurement techniques (material selection, sensor selection, physical principle of measurement...).

[0014] Yet another challenge is to find a fast production method: known techniques are lengthy, requiring at least 24 hours to carry out the nickel deposition around the fiber implemented, for example, in the technique described in the article by P. Stoll et al. mentioned above. [Prior art documents] [Non-patent literature]

[0015] [Non-Patent Document 1] A. Barrias et al., “A Review of Distributed Optical Fiber Sensors for Civil Engineering Applications,” Sensors, vol. 16, no 5, 2016, doi: 10.3390 / s1605074818 [Non-patent document 2] DD Francesca et al., "Qualification and Calibration of Single-Mode Phosphosilicate Optical Fiber for Dosimetry at CERN", J. Lightwave Technol., vol. 37, no 18, pp. 4643-4649, September 2019 [Non-patent document 3] Stoll, P. et al., "Embedding fiber optical sensors into SLM parts," 27th Annual International Solid Freeform Fabrication Symposium, pp. 1815-1825 (2016) [Non-patent document 4] Dirk Haverman et al., “Embedding optical fibers into stainless steel using laser additive manufacturing,” ICALEO 2013, 381 (2013), doi: 10.2351 / 1.5062904 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention aims to overcome these problems in whole or in part. [Means for solving the problem]

[0017] It firstly relates to a method for integrating sensors into metal parts, a) creating by additive printing a first portion of a metal part including a volume for accommodating a sensor, the volume having a width greater than the sensor; b) depositing a sensor in said receiving volume; c) creating a second portion of the metal part by additive printing, covering the sensor, to form molten puddles in the receiving volume on both sides of the metal tube of the sensor; Includes.

[0018] Preferably, additive printing of said second portion of the metal part over the sensor results in the formation of molten puddles in the receiving volume on either side of the sensor.

[0019] The metal in the molten puddle allows the sensor to be fixed to the wall of the containment volume upon cooling.

[0020] During cooling, the metal of the molten puddle adheres to the sensor on the one hand and to the edge of the receiving volume, more precisely to the edge of the layer facing the sensor on the other hand, and the bond thus formed extends continuously along the sensor in the direction of its extension and preferably also in relation to its height.

[0021] The sensor may be or include, for example, an optical sensor, including, for example, a Fabry-Perot cavity, or a Bragg network, or an optical fiber, for measuring, for example, temperature and / or stress and / or radiation quantities, for example by reflectometry, and / or a temperature sensor and / or a chemical sensor, including an optical fiber for measuring gases and / or pH and / or corrosion.

[0022] The sensor may also be or include a fiber optic sensor based on Rayleigh or Raman scattering, for example including an optical fiber and optionally a mirror in the tube.

[0023] For example, the optical fiber can be covered with a coating made of Al or Au or Cu, having a thickness of less than 20 μm.

[0024] Additive printing can be performed by scanning the surface of the powder bed, including the containment volume, by laser fusing on the powder bed, or by laser fusing wires or powder into a laser (techniques called "DED"), or by electron beam additive printing, or by DED (Directed Energy Deposition).

[0025] For example, a laser scans the surface of successive layers of a powder bed.

[0026] The receiving volume may have a convex shape, for example the shape of a channel in which the sensor may be deposited.

[0027] Additional printing is performed during step c) - Deposition of a layer of metal powder scanned by a laser in a manner perpendicular to the direction of extension of the sensor; - at least one scanning of the surface of the first layer covering the sensor with a laser beam and according to a direction parallel to the direction of extension of the sensor; can be implemented.

[0028] The method according to the invention may further comprise the steps of creating a recess below where the sensor must be placed and adding to this recess a solder sheet, which makes it possible to restrain the sensor at the bottom of the cavity.

[0029] The sensor may comprise an element sensitive to deformation, or to changes in temperature, or to stress, or to vibration, or to the amount of radiation, which sensitive element is arranged inside the metal tube. The method according to the invention may comprise one or more prior steps, for example, of forming or creating a sensor in the tube. For example, before step b), the sensor may be formed by introducing or forming in the tube an element or sensor sensitive to deformation, or to changes in temperature, or to stress, or to vibration, or to the amount of radiation. More specifically, the step of forming a sensor in the tube comprises: Inserting a metal rod into the tube; Inserting an optical fiber, one end of which is at a distance (L c ) facing one end of the rod, these two ends defining a Fabry-Perot cavity; may include:

[0030] The metal rods can be secured to the tube by, for example, soldering, and the optical fibers can be secured to the tube by, for example, gluing.

[0031] In the method or device according to the invention, the metal part can be made of, for example, steel, or made of a titanium alloy, for example Ti64, or made of Cu, or made of Nb, or made of Cr, or made of W.

[0032] The present invention also provides an integrated device including a sensor in a metal part, comprising: a channel including the sensor; a homogeneous mass of material surrounding said sensor and of the part to which said sensor is fixed; The present invention relates to an integrated device including:

[0033] The integrated device sensor according to the invention is directly surrounded by the material of which at least one parameter (for example deformation and / or temperature...) must be measured, in other words there is no thick intermediary between the sensor itself and the environment to be measured.

[0034] According to one embodiment, the sensor comprises a Fabry-Perot cavity and / or a temperature sensor or a Bragg network for measuring temperature and / or stress and / or radiation quantities, for example by reflectometry, or a sensor, for example an optical fiber and / or a chemical sensor comprising an optical fiber for measuring gases and / or pH and / or corrosion. The sensor can also be an optical fiber sensor based on Rayleigh or Raman scattering.

[0035] In a sensor including a Fabry-Perot cavity, the Fabry-Perot cavity may be formed between one end of a metal rod and one end of an optical fiber. [Brief explanation of the drawings]

[0036] [Figure 1A] 1 illustrates an embodiment of the method according to the present invention. [Figure 1B] 1 illustrates an embodiment of the method according to the present invention. [Figure 1C] 1 illustrates an embodiment of the method according to the present invention. [Figure 1D] 1 illustrates an embodiment of the method according to the present invention. [Figure 1E] 1 illustrates an embodiment of the method according to the present invention. [Figure 2] 1 shows the change in heat penetration in a metal powder according to the time of exposure of the metal powder to a laser. [Figure 3A] 1 shows a laser scanning strategy in the context of the method according to the invention; [Figure 3B] FIG. 3B is an enlarged view of a portion of FIG. 3A. [Figure 3C] 1 shows in plan view the steps of passing a laser parallel to the tube containing the sensor. [Figure 4] 1 illustrates an embodiment of an example of a sensor for implementation in the context of the present invention. [Figure 5A] 1 shows a cross-sectional view of the integration of a sensor implementing the method according to the invention; [Figure 5B] 1 shows a cross-section of an integration attempt in a known manner. [Figure 6] 1 shows a test specimen equipped with a Fabry-Perot sensor. [Figure 7] 1 shows the change in deformation of a Fabry-Perot sensor during the rise and fall of a tensile test specimen made in accordance with the present invention. [Figure 8] 1 shows an optical measurement of the length Lc. [Figure 9] 1 shows a test specimen being measured in a tensile tester. DETAILED DESCRIPTION OF THE INVENTION

[0037] The steps of one embodiment of the method according to the invention are shown in Figures 1A to 1E, which illustrate the integration or incorporation of a metal tube containing a sensor into a part or metal component (here steel, but also Ti64 (an alloy of titanium, aluminum and vanadium), or Cu, or Nb, or Cr, or W, or any metal that can be used in additive manufacturing).

[0038] The method according to the invention can implement the technique of additive printing by fusion on a powder bed. According to this technique, the material selected to create the part or metal part is deposited layer by layer, for example by one or more nozzles controlled by a computer. The material of each layer can be melted by a laser beam. Other techniques can be used to perform the fusion step in the context of the invention, such as electron beam additive manufacturing (EBM, or electron beam melting) or DED (directed energy deposition). Each layer can have a thickness of, for example, between a few micrometers and a few tens of micrometers, for example between 10 μm and 500 μm, depending on the method, powder, and machine implemented. The part or metal part can be designed in advance using computer-aided design (CAD) techniques. Additional information on this technology of additive printing by fusion on a powder bed can be found, for example, in the article by N. Shahrubudina et al., "An Overview on 3D Printing Technology: Technological, Materials, Applications", 2nd International Conference on Sustainable Materials Processing and Manufacturing (SMPM 2019), Procedia Manufacturing 35 (2019) 1286-1296, and in the references cited in this article.

[0039] The following formula (adapted from the work by R. Poprawe, Tailored light 2: Laser Application Technology. Heidelberg, Springer, 2011) can be used to calculate the thermal penetration δ of the heat provided by the laser beam onto the layer, where α316L is the thermal diffusivity of the selected steel and t is the time. δ=√4*α316L*t (Equation 1)

[0040] This equation can be generalized to other metals by replacing the coefficient α316L with the thermal diffusivity coefficient of the material in question.

[0041] For the example intended use, a heat penetration of 60 μm is desired, which corresponds to twice the thickness of the layer of powder to be deposited to ensure good density of the material. Also, a heat penetration corresponding to twice the thickness of the layer of deposited powder generally does not damage the sensor when it is covered by the material of the part (see creation of the second, or top, part of the part, as explained below).

[0042] The variation of the heat penetration δ (according to equation 1 above) according to the time t of exposure to the laser is shown in Figure 2. The time of exposure makes it possible to define the speed of the laser's passage. In the example chosen, for a heat penetration of 60 μm, the time of exposure is 82 μs. This time of exposure makes it possible to define the speed of the laser.

[0043] According to the technique implemented in the context of the present invention, the sensor here comprises a sensitive element in a metal tube, A first part 2 of the part, called the lower part, is created (FIG. 1A), which includes a receiving volume 4 (a channel in the example shown) that allows to receive a metal tube 20 (FIG. 1B, where a sensor placed in cavity 4 is visible) while including an upper opening 5 that leaves a space between each side of the tube and the material to be deposited by additive printing to form a molten puddle as explained below. Volume 4 thus defines a concave surface in part 2 of the part, which itself has a convex shape, which, in a cross section perpendicular to the longitudinal direction of its extension, can have the shape of a part of a cylinder or of an ellipse, The sensor is inserted into this storage volume 4 (FIG. 1B), maintaining a distance or gap d between the outer surface of the tube and the edges 8, 10 of the storage volume 4, in fact the edges of the powder layer, this gap preferably being chosen to correspond to the width of the molten puddle (see below), which can be for example 50 μm on each side of the metal tube, preferably taking into account the geometric tolerances of the machine used, which in this example is a Trumpf TruPrint 1000 machine. The tube is then fixed by laser solder at several points 11, 13 along it (see FIGS. 1C and 1D, the latter being a top view), so that, as can be seen in FIGS. 1B and 1C, the tube protrudes above the level defined by the upper surface 3 of the first part 2, The second part 6 of the part, called the top, is then created by additive printing (FIG. 1E). A laser is scanned over the deposited layer in a manner perpendicular to the metal tube 20, stopping at a distance defined by the lateral gap between the tube and the edges 8, 10 of the receiving volume 4, allowing the molten material to flow into the receiving volume 4. This leads to the formation of a molten puddle on both sides of the metal tube 20. During cooling, the metal of the molten puddle adheres to the metal tube on the one hand and to the edges 8, 10 of the receiving volume, more precisely to the edges of the layers facing the tube 20, on the other hand. The bond thus formed extends continuously along the tube in accordance with the direction of extension and height of the tube. The molten puddle is generated after the placement of the fiber in the volume 4 and results from the interaction between the laser and the metal powder when the top is created.

[0044] The movement of the laser beam over the various layers on top or upper surfaces is shown schematically in Figures 3A and 3B, which are top views of the section including the tube 20, and Figure 3B is a detailed view of a portion of Figure 3A; Initially, the laser beam scans the material following trajectories perpendicular, and preferably only perpendicular, to the direction of extension of the tube 20 (FIGS. 3A and 3B), these scans making it possible to form a liquid bath, as explained above, when the laser arrives near the edges 8, 10. Scanning not perpendicular to the fiber leads to overheating of the fiber, which becomes malleable and the sensor is no longer useful; The laser beam is guided in a parallel manner to the tube 20 on the first layer of printing covering the tube (Figure 3C), and this parallel pass (in fact, a single parallel pass) makes it possible to strengthen the bond between the tube and the part.

[0045] Figure 3A also shows the possibility of several sensors at the same time: here four sensors are shown, but there can be any number N (N=1 or N>1).

[0046] The above technique can be optimized to ensure better adhesion between the tube 20 and the component, in particular a recess can therefore be made under the sensor into which a solder sheet 15 can be inserted (see Figure 1C) and the assembly, including this sheet, can be placed in an oven, for example at approximately 700°C, to melt the sheet and create a bond between the component and the tube.

[0047] For example, the parameters chosen for the implementation of the invention on 316L steel are the following (parameters that can be modified depending on the material and / or machine used; in this example the laser is a fiber-by-tterbium laser with a wavelength of 1064 nm): Power = 80W, Speed ​​of laser movement on the surface of the layer = 642 mm.s -1 , The spacing between adjacent zones of the laser beam scanning is δ=70 μm. Height of each layer of powder = 30 μm, Laser spot size = 30 μm is.

[0048] The creation of a sensor that can be used in the context of the present invention will now be described. In this example, it is a miniature Fabry-Perot sensor, which makes it possible to measure the mechanical stress applied to the part on which the sensor is placed. This type of sensor is reliable, accurate and robust. Other sensors can be used, examples of which are given above and in the present application, among which are temperature and / or chemical sensors comprising Bragg networks or optical fibers for measuring temperature, and / or stress and / or radiation quantities (measurement by reflectometry), and / or optical fibers for measuring gases, and / or pH, and / or corrosion...

[0049] To do this, a metal tube 20, for example made of 316L steel, is selected (FIG. 4), the inside diameter D of which is capable of accommodating, on the one hand, a metal rod 28 and, on the other hand, an optical fiber 26. It is this tube 20 that is then positioned as shown in FIG. 1B.

[0050] This tube 20 is made for example of stainless steel, for example again 316L (for example from the supplier UNIMED), and it can have dimensions of 200 μm (inner diameter) / 400 μm (outer diameter), although other dimensions can be used, for example between 80 μm and 1 mm for the inner diameter and between 200 μm and 10 mm for the outer diameter. It has a length of several tens of mm, for example 50 mm, and it can be perforated and then its outer surface polished to make it easier to handle.

[0051] The rod 28 used is made of metal, for example steel, for example 316L steel again (supplied by GoodFellow), and has a length Lt (for example Lt=1 mm), one end 29 of which can be polished with paper of for example 30 μm, 16 μm, 9 μm, 3 μm, 1 μm and then 0.3 μm, so as to have a flat surface 10 which will allow the reflection of light.

[0052] This rod 28 can be placed and fixed to the tube 20, for example, by soldering (reference numeral 21 denotes the soldering point). The soldering 21 is performed inside the tube via laser welding (for example, a pulsed laser with a wavelength of approximately 1 μm, U=234 V, t (pulse duration)=1.0 ms, f (pulse repetition frequency)=1 Hz; the laser beam is directed onto the tube, melting it locally and bonding it to the inner rod). Once this step has been performed, an optical fiber with a diameter of, for example, 125 μm and provided with a coating made of, for example, aluminum (supplied by IXblue / Fiber Guide), gold, or copper can be placed in the tube facing the metal rod (FIG. 4) at a distance Lc from it; this coating has a thickness of less than 20 μm, allowing it to resist temperatures. It should be noted the difference between this thin coating, which is applied to the entire optical fiber, and the very thick layer of nickel that must be applied to the fiber in the document by P. Stoll et al. already cited above. The deposition of this very thick layer required additional work, which is very precise and time-consuming (the production of a 200 μm layer of nickel, as described in this document, requires approximately two days, while the production of a sensor according to the invention requires approximately three hours). The fiber can then be fixed to one end 36 of the tube 20, for example with ceramic glue 34. Interference fringes can thus be formed, which make it possible to measure the distance Lc and to obtain the deformation of the part to which the tube 20 is fixed.

[0053] The miniature sensor thus created has the property of not degrading the mechanical properties of metal parts made of steel, on the one hand through its chemical composition (316L) and on the other hand through its small size, since the outer diameter of the tube 20 is generally <1 mm.

[0054] To illustrate the feasibility of the technology according to the invention, a part integrating a tube 20 containing a Fabry-Perot type sensor was produced, on the one hand, by the method according to the invention (FIG. 5A) and, on the other hand, by a method based on known technology. In FIG. 5A, which is a cross section of the part perpendicular to the direction of extension of the optical fiber 26, it can be seen that the sensor is well integrated into the part; in this figure, the integration of this assembly is so complete that neither the tube 20 (which is shown with a dotted line around the fiber 26) nor any of the layers deposited by 3D printing are visible, whereas integration with known methods would have failed, as can be seen in FIG. 5B, which reveals the destruction of the metal tube and of the fiber it contains (in each of these two figures, the black mark at the bottom corresponds to the space below the fiber, and the additive manufacturing has been carried out from the top).

[0055] The results in Figures 5A and 5B demonstrate the robustness and reliability of the present invention for the integration of a sensor, here an optical Fabry-Perot sensor. The method according to the present invention makes it possible to obtain a complete integration of the sensor into the component without the need to previously provide the fiber with a thick layer of nickel.

[0056] Also, some differences between the present invention and the technique described in the document by P. Stoll et al. already mentioned above can be noted here, namely: In this document, a thick layer of nickel is added around the fiber. Such a thick layer is neither necessary nor implemented in the context of the present invention. The technique described in the article by P. Stoll et al. implements scanning of the laser according to trajectories that are alternately perpendicular and parallel to the wire, but as already explained above, non-perpendicular trajectories lead to overheating of the fiber (hence the need for a thick layer of nickel around the fiber in this article).

[0057] The present invention does not implement a thick coating around the fiber, which would take too long to fabricate, and it implements scanning perpendicular to the fiber, which makes it possible to obtain perfect integration of the fiber into the final component. The present invention makes it possible to fabricate several sensors simultaneously, as can be seen for example from FIG. 3A, in a much shorter time than with the technique described in the article by Stoll et al. already cited above (a technique that requires at least 24 hours to fabricate just a fiber, which then has to be integrated).

[0058] Through the method according to the invention, a test specimen 40 was produced (FIG. 6) which was measured by a Fabry-Perot sensor, making it possible to demonstrate that it is possible to measure deformations of a structure in an accurate manner (deformations are measured from inside the part by the sensor).

[0059] The length Lc (which is the length of the Fabry-Perot cavity, see Figure 4) decreases or increases according to the force applied to pull the part, and by measuring the movement Lc, it is therefore possible to know whether the structure remains in the elastic region and therefore in its correct operating mode. When a stress is applied on the part to deform it, L C It can be observed that Lc increases and when this stress is stopped, Lc returns to its original length (Fig. 7). The difference that can be noted in Fig. 7 between the data for the ascent and the descent is explained by the work hardening method (shown in Fig. 8): when the material of the tube is deformed, its relaxation leads to a reduction in the load and the deformation is not the same as when the material is stretched (relaxation phenomenon).

[0060] The experimental device used is shown in FIG. 9 and includes a tensile test specimen measured with a Fabry-Perot sensor, a spectrometer (not shown) for analysis of the signal coming from the sensor, and a tensile tester 50 .

[0061] It is noted that the Fabry-Perot sensor placed inside the test specimen 40 being measured gives the same deformation as the tensile test specimen (measurements are performed on a tensile tester), and because the measurements were performed in the elastic region, the sensor returns to its nominal value, i.e., here 0% deformation.

[0062] This measurement therefore makes it possible to check the reliability of the sensor (it also returns to its original length once the stress is stopped), its robustness (measurements are possible after the sensor is integrated into a metal component), as well as its precision (precise measurements with a theoretical resolution of ±0.1 μm).

[0063] The Fabry-Perot sensor used here allows for the measurement of mechanical deformations of a part caused by a tensile tester, which deformations may also be caused by, for example, temperature fluctuations.

[0064] The invention can be applied in the nuclear field, in the automotive field, in the field of space or aeronautics, etc. By implementing the invention, sensors can be inserted into parts made by additive manufacturing that are used in any one of these fields to measure the dimensional variations of the part when it is subjected to various stresses.

[0065] The present invention provides various advantages, namely: The optical signal of the optical fiber is not degraded by the technique of additional impressions; the technique according to the invention can be adapted to any type of object that one wishes to create by metal additive manufacturing; This makes it possible to measure, via the integrated sensor according to the invention, the component in which the sensor is integrated, It has. [Explanation of symbols]

[0066] 2. First Part 3 Top surface 4. Capacity 5 Top opening 6 Second Part 8. Edge 10. Relationship 11 points 13 points 15 Solder sheet 20 metal tubes 21 soldering points 26 Optical Fiber 28 Metal Rod 29 one end 34 Ceramic glue 36 one end 40 Test specimens 50 Tensile testing machine

Claims

1. 1. A method for integrating a sensor into a metal part, comprising: a) producing by additive printing a first portion (2) of said metal part, said first portion (2) including a volume (4) for accommodating a sensor, said volume having a width greater than that of said sensor; b) depositing said sensor in said receiving volume (4); c) producing by additive printing a second part (6) of the metal part, covering the sensor, forming molten puddles in the receiving volume (4) on both sides of the sensor; A method comprising:

2. 2. The method of claim 1, wherein the sensor is an optical sensor, such as a Fabry-Perot cavity, or a temperature sensor or a Bragg network, or an optical fiber for measuring temperature and / or stress and / or radiation quantities by reflectometry, or a chemical sensor comprising an optical fiber for measuring gases and / or pH and / or corrosion.

3. 3. The method according to claim 1 or 2, wherein the additive printing is performed by laser fusing on a powder bed, or by laser fusing of wires, or by jetting powder into a laser, or by electron beam additive printing, or by DED (Directed Energy Deposition).

4. 3. The method according to claim 1 or 2, wherein the additive printing is performed by scanning the surface of a powder bed, including the receiving volume (4).

5. 3. The method according to claim 1 or 2, wherein the storage volume (4) has a convex shape.

6. 3. The method according to claim 1 or 2, wherein the additive printing implements a layer of metal powder scanned by a laser in a manner perpendicular to the direction of extension of the sensor (20) during step c).

7. 3. The method according to claim 1, further comprising, during step c), at least one scanning of the surface of the first layer covering the sensor by a laser beam and according to a direction parallel to the direction of extension of the sensor.

8. 3. The method of claim 1 or 2, further comprising the steps of creating a depression below where the sensor must be placed, and adding a solder sheet (15) to the depression.

9. 3. The method according to claim 1 or 2, wherein the sensor comprises an element sensitive to deformation, or to changes in temperature, or to stress, or to vibration, or to the amount of radiation, the sensitive element being arranged inside a metal tube (20).

10. The step of forming the sensor in the tube comprises: Inserting a metal rod (28) into the tube (20); Inserting an optical fiber (26), one end of which is at a distance (L ｃ ) facing one end of the rod, the two ends defining a Fabry-Perot cavity; 10. The method of claim 9, comprising:

11. 11. The method according to claim 10, wherein the metal rod (28) is fixed to the tube (20), for example by soldering (21).

12. 11. The method of claim 10, wherein the optical fiber (26) is fixed to the tube (20), for example by gluing (24).

13. 3. The method according to claim 1 or 2, wherein the metal part is made of steel or made of a titanium alloy, such as Ti64, or made of Cu, or made of Nb, or made of Cr, or made of W.

14. An integrated device including a sensor in a metal part, a channel (4) containing said sensor; a homogeneous mass of material of the metal part surrounding the sensor and to which the sensor is fixed; Integrated devices, including:

15. 15. The device of claim 14, wherein the sensor comprises a temperature or chemical sensor comprising a Fabry-Perot cavity or a Bragg network, or an optical fiber for measuring temperature and / or stress and / or radiation amounts by reflectometry, and / or an optical fiber for measuring gas, pH, corrosion.

16. 16. The device of claim 14 or 15, wherein the sensor comprises a Fabry-Perot cavity formed between one end of a metal rod (28) and one end of an optical fiber (26).

17. 16. The device according to claim 14 or 15, wherein the material of the metal parts is made of steel or made of titanium alloy, for example Ti64, or made of Cu, or made of Nb, or made of Cr, or made of W.

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