Method for dimensional inspection of a component during additive manufacturing of a component

Abstract

One aspect of the invention relates to a method for dimensional inspection of at least one component manufactured by an additive manufacturing machine, the steps of additive manufacturing being performed by successive deposition of a powder bed and melting of the powder bed after each deposition, the method comprises the following steps: acquiring an image of the part being manufactured after at least one step of depositing and melting the powder bed; -comparing the image with an image of a reference template; -checking the dimensional compliance of the component based on the comparison.

Description

Technical Field

[0001] The technical field of the invention is the verification of the conformity of components manufactured by additive manufacturing.

[0002] The invention relates to a method for dimensional inspection of at least one component produced by an additive manufacturing machine. Background Art

[0003] Additive manufacturing is a machining technology whose advantage is the ability to manufacture objects with complex shapes. This technology is used, for example, in the aerospace industry to manufacture cooling circuits for gas distributors, air circuits in blades or fuel circuits in fuel blocks.

[0004] The principle of additive manufacturing is to produce an object by successive additions (also called passes) of one or more materials, and to assemble the material of each pass with the material of the previous pass. Additive manufacturing machines rely on different deposition and assembly technologies. For example, some machines utilize the principle of using a laser beam to melt and cool a material (usually in powder form). Other machines may be based on sintering or polymerization of materials.

[0005] A disadvantage of additive manufacturing technology is that, typically, the parts are not accessible during manufacturing, for example for inspection to verify manufacturing compliance. In fact, access to the inside of the machine is limited by the compactness of the machine and the overall size of the part or parts being manufactured. In addition, for reasons of safety, equipment fragility and ensuring manufacturing quality, the atmosphere within the additive manufacturing booth is highly controlled and sealed.

[0006] In this context, for machines based on powder metal laser melting technology, the compartment atmosphere consists of a mixture of gases (sometimes toxic) and volatile residues of the metal powder, which represents a non-negligible health risk for the user, especially in case of inhalation. Moreover, this type of technology requires that the powder material be as free of parasitic particles as possible, which is impossible if the compartments are not hermetically sealed throughout the manufacturing process. If this is the case, the quality of the manufactured parts will be seriously degraded, they will become brittle and even non-compliant. Finally, the fragility of the machine's equipment, such as the nozzle and the laser, is incompatible with handling for inspection purposes during the manufacturing process. In fact, the compactness of these machines makes it difficult to carry out inspections without compromising the settings or the proper operation of the equipment.

[0007] Therefore, it is not practical to assess the conformity and manufacturing quality of the mechanical components being manufactured.

[0008] What is really interesting, however, is checking the quality and integrity of a part while it is being manufactured. Indeed, although additive manufacturing technology is well-mastered, uncertainties related to the compliance of a final part to specifications still exist. As with any manufacturing process, these uncertainties may lie in the manufacturing process, the quality of the powder chosen, or hardware or software risks related to the environment. Being able to check the integrity and quality of a part during manufacturing would enable non-compliance to be detected at an early stage, rather than after the part has been completely manufactured. The manufacturing process could then be modified to prevent the part from becoming non-compliant.

[0009] This interest in in-process inspection is even more pronounced for the manufacture of parts with complex internal geometries, especially the manufacture of cavities or recesses in the case of blades. In fact, these internal geometries are subject to strict geometrical constraints in order to be finally assembled on a suitable machine and to correctly perform their function. In the case of blades, these parts must comply with maximum overall size constraints in order to be assembled on an aircraft. In addition, the function of these blades is to circulate a very controlled airflow in order to de-ice one or more parts of the aircraft. If the internal geometry of such a blade is not in compliance with the specifications, the airflow may be too impaired and the de-icing function of this fluid will not be achieved or will not be achieved correctly.

[0010] From the prior art, non-destructive volumetric inspection methods are known, such as ultrasound imaging, infrared photography, X-ray photography, X-ray tomography, thermography, etc. These methods are used to assess the compliance of a component after it has been manufactured by an additive manufacturing machine. However, these methods require special equipment that should be placed close enough to the component for the inspection to reliably assess the internal health state of the component, which is not always compatible with the external geometry of the manufactured component. Furthermore, these conventionally known inspections prove to be unreliable for large material thicknesses, which are typically greater than 50 mm (or even less if the mechanical properties of the material are complex and not conducive to non-destructive inspection).

[0011] Furthermore, some methods are difficult to apply on a large scale in the mass production of parts because they require large equipment that can only assess the compliance of one part at a time and is often very expensive. Furthermore, in some cases, the inspection machine cannot inspect the entire part and / or cannot be used to inspect parts with dimensions exceeding some threshold. One such method is, for example, infrared tomography.

[0012] Destructive inspection methods such as dissection are also known. These methods allow the internal compliance of a component to be directly checked, which compromises its future use, since the component will be unusable or destroyed. This type of inspection is therefore not considered within the scope of large-scale production of components using additive manufacturing.

[0013] Therefore, there is a need for a device for checking the compliance of a part while it is being manufactured using additive manufacturing techniques. Summary of the invention

[0014] The object of the present invention is to solve the drawbacks of the prior art by providing a method for dimensional inspection of mechanical components that can be implemented during the component manufacturing process.

[0015] A first aspect of the invention relates to a method for dimensional inspection of at least one component manufactured by an additive manufacturing machine, the additive manufacturing being performed by successive deposition of a powder bed and melting the powder bed after each deposition, the method comprising the following steps:

[0016] - acquiring an image of the part being manufactured after at least one step of depositing and melting a powder bed;

[0017] - comparing the image with an image of a reference template;

[0018] - Verifying dimensional compliance of the component based on the comparison.

[0019] "Dimensional compliance" refers to the compliance of the internal geometry and / or external geometry of a mechanical component with respect to the specifications for the manufacture and use of the component.

[0020] According to this first aspect, by acquiring images after melting each pass of the powder deposited onto the powder bed, the geometrical compliance of the component can be assessed at any time during the manufacture of the component by additive manufacturing. This enables the prediction or detection of any internal or external dimensional non-compliance of the component being manufactured at an early stage.

[0021] The advantage of this type of inspection is that, on the one hand, when a component is verified as no longer compliant during its manufacture, the manufacture of the component can be stopped, and on the other hand, if non-compliance is predicted, the manufacturing process of the component can be modified to ensure compliance of the component throughout its manufacturing process. Therefore, this method can reduce the amount of material lost due to the manufacture of non-compliant components.

[0022] Furthermore, the method is simple to implement and requires minimal acquisition and processing equipment.

[0023] Advantageously, the method is not limited to additive manufacturing techniques based on fused powder beds, but can also be applied to other types of additive manufacturing techniques.

[0024] The method according to the first aspect of the present invention may also have one or more of the following features, which may be employed alone or in any technically possible combination.

[0025] In one embodiment, the acquiring step is performed by a Metal Oxide Semiconductor (CMOS) sensor camera or a Charge-Coupled Device (CCD) sensor camera arranged in the machine.

[0026] By this embodiment, the method requires minimal, space-saving equipment to implement.Preferably, the camera used is a CMOS camera, since CMOS cameras provide better image contrast than CCD cameras.

[0027] In one embodiment, each acquired image comprises an inner contour and / or an outer contour of the component being manufactured, the inner contour defining the perimeter of the interior space of the component in the image and the outer contour defining the outer perimeter of the component in the image.

[0028] In one embodiment, the reference template comprises at least one set of images of at least one reference component and is obtained following the steps of:

[0029] - a step of acquiring an image after each step of depositing and melting the powder bed when manufacturing a reference part;

[0030] - a step of measuring the dimensions of the reference part after manufacturing the reference part;

[0031] - a step of verifying the compliance of the reference component by comparing its dimensions with those provided by the specification;

[0032] The template includes a set of acquired images of reference parts that are inspected for compliance.

[0033] By this embodiment, the reference template used to verify the dimensional compliance of a part while it is being manufactured represents the manufacture of a compliant part by additive manufacturing. In fact, the template is obtained from at least one reference part that is verified as compliant after manufacturing. The compliance is verified according to the specification of the part, which specifies the internal and external dimensions of the final part, etc. Therefore, since the final part is verified as compliant, the images acquired throughout its manufacturing process represent the manufacture of a compliant part. Therefore, the reference template containing all these images represents the manufacture of a compliant part by additive manufacturing.

[0034] Advantageously, the template is able to take into account the phenomena of expansion and contraction of the material associated with the melting action of the laser. In effect, the template comprises images "acquired hot" (i.e. during the manufacture of the reference part, and therefore when the part is subject to expansion), while the compliance of the reference part is verified "cold" (i.e. once the part has been manufactured, i.e. when the material of the part has contracted). The template thus provides a robust verification of part compliance for the additive manufacturing process.

[0035] In one embodiment, measuring the dimensions of the reference component after it is manufactured is accomplished by X-ray or sectioning.

[0036] In one embodiment, the reference template is obtained from a plurality of reference parts, each reference part that is inspected to meet specifications is associated with a set of acquired images of the part, the reference template comprising the plurality of acquired sets of images.

[0037] Through this embodiment, the reference template is obtained by statistically studying multiple parts. This makes the template more robust to verify the compliance of the parts during manufacturing.

[0038] In one embodiment, the reference template is obtained from at least two reference components to correspond to a first group of images and a second group of images acquired respectively, wherein the acquired images in the first group of images include a minimum inner contour and / or a minimum outer contour, and the acquired images in the second group of images include a maximum inner contour and / or a maximum outer contour.

[0039] By this embodiment, the method enables to define in the template the internal and / or external geometrical limits of the part contour, in particular the internal and / or external geometrical limits related to the internal cavity on which the dimensional compliance of the part is established. The template is therefore an easy to use tool for checking compliance.

[0040] In one embodiment, the reference template is obtained from the average between the contours of multiple sets of images of each reference component.

[0041] In one embodiment, the reference template comprises at least one set of images of at least one reference component and the method further comprises the step of superimposing an image of the reference template on the acquired image after each image acquisition step.

[0042] By means of this embodiment, verifying the compliance of a component using a template is quickly and easily implemented.

[0043] In one embodiment, the method comprises the step of stopping manufacturing and / or modifying parameters of the additive manufacturing machine if the part being manufactured does not have dimensional compliance.

[0044] By this embodiment, the manufacture of non-compliant parts can be stopped, and no more material is used to manufacture the non-compliant parts because the non-compliant parts will be scrapped after manufacture. This also enables the parts production time to be shortened, especially in the case of mass production.

[0045] Furthermore, this embodiment enables the correction of expected component non-conformities. Indeed, since the manufacturing history of one or more reference components is known through all thermally acquired images, deviations from this manufacturing history of the reference components can be detected during manufacturing. This enables the operation of the additive manufacturing machine to be modified on the fly during manufacturing to prevent any non-conformities of the components.

[0046] This embodiment therefore enables a reduction in the number of non-compliant parts manufactured, and a reduction in the amount of material lost due to manufacturing parts that will ultimately be non-compliant.

[0047] Another aspect of the invention relates to a computer program product comprising instructions which, when the program is executed on a computer, cause it to implement the steps of the method according to the invention.

[0048] A final aspect of the present invention relates to a computer-readable recording medium comprising instructions which, when executed by a computer, cause it to implement the steps of the method according to the present invention.

[0049] The invention and its various applications will be better understood by reading the following description and examining the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The drawings are presented by way of illustration and not for the purpose of limiting the invention in any way.

[0051] - Figure 1 The interior of an additive manufacturing machine is shown.

[0052] - Figure 2 is a block diagram showing the sequence of steps of the method according to the present invention.

[0053] - Figure 3 is a graphical representation of the minimum and maximum inner and outer contours obtained during a step of the method according to the invention. DETAILED DESCRIPTION

[0054] Unless otherwise stated, the same element appearing in different drawings has a single reference number.

[0055] A first aspect of the invention relates to a method for dimensional inspection of a component manufactured by an additive manufacturing machine, also known as a 3D printer. Figure 1Provides photos of the interior of the additive manufacturing machine.

[0056] The additive manufacturing machine 10 (also referred to as a 3D printer 10) is here based on the technology of laser melting of a powder bed 16. For this machine 10, a powder bed 16 is formed by continuously depositing controlled amounts of powder. After each layer is deposited, the layer of powder is melted by a laser 14, the beam of which is controlled by a dichroic mirror 12 and a photodiode 13 and directed by a scanner 11. The powder bed 16 is formed on a build tray 17 suitable for accommodating the powder bed 16. The melting of the powder in the powder bed 16 takes place at the position of a laser focus 18 on the powder bed 16. The position of the focus 18 is controlled by a scanner 11. This is, for example, an EOS M290 machine.

[0057] Advantageously, the machine 10 comprises an objective lens suitable for image acquisition. The objective lens is, for example, a camera 15, which is placed in the machine 10 so as to have in its field of view the entire area defined by the powder bed 16. Preferably, the camera 15 is positioned in the machine in such a way that it does not hinder the propagation of the laser beam from the scanner 11 to the powder bed 16. The camera 15 is used to acquire, layer by layer, images of the powder bed of the manufactured part.

[0058] Preferably, the camera 15 is a complementary metal oxide semiconductor (CMOS) type camera 15a. Alternatively, the camera 15 is a charge-coupled device (CCD) camera (15b). The advantage of using a CMOS camera 15a instead of a CCD camera 15b is that the CMOS camera 15a produces an image with a higher contrast. This is advantageous for the method according to the invention, which is based on the detection of contrast differences in the image acquired by the camera 15, as described below. The image acquired by the camera 15 may be an image in the infrared spectrum and / or an image in the visible spectrum.

[0059] It should be noted that Figure 1 The positions of the CMOS 15a and CCD 15b cameras in the figure are merely illustrative and in no way represent a limiting implementation of these cameras in the machine 10. Moreover, only one of these cameras 15 is sufficient to implement the method according to the invention. The presence of two cameras CMOS 15a and CCD 15b in the figure is also only for illustrative purposes.

[0060] According to the method of the present invention, Figure 2 The method 100 comprises eight consecutive steps numbered 101 to 108 .

[0061] Step 101 is the step of acquiring a set of images of a reference part being manufactured by the machine 10. Preferably, acquiring images of the reference part being manufactured is performed after the laser 14 has melted each layer of powder deposited onto the powder bed 16.

[0062] These images are therefore referred to as "hot" images, since they are obtained after the powder has been melted by the laser 14. At this point, the material is subject to a strong temperature gradient, since the room temperature in the machine is between 5°C and 100°C, and in the case of metal powders, the melting temperature of the powder is between 1500°C and 2500°C. This strong temperature gradient therefore produces a contraction effect of the melted material, in which the material expands as the powder melts and then contracts as it cools. In addition, there is also an annealing phenomenon of the material, since melting a layer may involve re-melting a previously melted layer or layers of powder that were located directly below the newly melted layer of powder.

[0063] Therefore, the advantage of acquiring a thermal image is that it is possible to take into account the thermal expansion imposed on the material throughout the manufacturing process of the component (here the reference component).

[0064] For this application example, it is considered that the manufactured part is a blade, which is designed with the aid of computer-aided design software according to specifications specific to the blade, and which includes an internal cavity for airflow to pass through. Therefore, the advantage of acquiring images throughout the manufacturing process of the blade is that the formation of the internal cavity can be observed layer by layer.

[0065] Preferably, the reference component is designed so that the internal cavity has the minimum size allowed by the specification. For example, the component is designed so that the perimeter of its internal cavity or other characteristic dimensions of the cavity are equal to the minimum perimeter of the cavity allowed by the specification.

[0066] Then, step 102 is a step of measuring the dimensions of the reference part after it has been manufactured.

[0067] "Dimension" refers to a geometric quantity whose value is specified by a specification. For example, in the case of a blade, the internal dimensions of the cavity are measured, such as its length, width, height and perimeter.

[0068] Optionally, the outer dimensions of the blade are measured, such as the length, width, height and outer perimeter of the component.

[0069] These measurements may be performed by non-destructive inspection techniques, such as by infrared or X-ray imaging, or by destructive inspection, such as by sectioning the component.

[0070] The purpose of this step 102 of measuring the dimensions of the component is to evaluate the dimensions of the reference component after manufacture. Therefore, "cold" measurements are considered herein, ie measurements after the reference component has been manufactured and cooled.

[0071] Then, step 103 is a step of checking the compliance of the reference component. The compliance of the reference component is evaluated by comparing the cold measured dimensions of the reference component with the dimensions prescribed by the specification.

[0072] In the checking step 103, the reference part is defined as compliant if the cold measured dimensions are consistent with the dimensions specified in the specification. For example, a dimension is specified if it is less than or greater than a predetermined threshold, or is within a predetermined tolerance interval.

[0073] In this paper, a reference blade is defined as compliant if its internal cavity dimensions are consistent with the cavity dimensions specified by the specification.

[0074] Then, step 104 is a step of determining a reference template according to the compliant reference component.

[0075] In particular, the reference template is formed by images of the reference component acquired during the manufacture of the component. In other words, the template is formed by thermal images of the reference component. Preferably, the template comprises all images of the reference component acquired while it is being manufactured.

[0076] Optionally, the template is determined by applying a contour detection operation (i.e., an operation that automatically detects the contours of shapes in the image, for example by contrast differences) to each acquired image. Thus, the contour detection operation enables only one or more contours of the reference component to be retained in the image. In particular, the contour detection enables the contour of the internal cavity of the reference component to be detected. In other words, each acquired image includes an inner contour of the component being manufactured, which defines the perimeter of the internal space of the component in the image.

[0077] These contours are shown in Figure 3 In the figure, the profile 300 includes an inner profile 301, which includes a minimum inner profile 301a and a maximum inner profile 301b. Also shown is an outer profile 302 including a minimum outer profile 302a and a maximum outer profile 302b.

[0078] Thus, the template may include only the inner contours 301 detected in each of a set of thermal images of the reference component. Thus, the template includes a set of contours 300 defining an inner cavity whose dimensions are minimal, since the reference component is preferably designed such that the inner cavity dimensions of the blade are the minimum dimensions allowed by the specification. These are referred to as minimum inner contours 301a.

[0079] In summary, the template comprises the smallest inner contour 301a allowed by the inner cavity for the manufacture of the blade at each moment of manufacture.

[0080] Advantageously, the template takes into account thermal expansion of the component during manufacture.

[0081] Then, step 105 is a step of obtaining one or more images of the new component to be manufactured. The new component is a new blade in this case. The image is obtained by camera 15.

[0082] Thus, the acquired image is a thermal image of the new component being manufactured.

[0083] Then, step 106 is a step of comparing the acquired image with the reference template. The image is preferably acquired after melting the deposited powder of each pass. The pass at which the image is acquired is, for example, a pass associated with a predefined pass number. Alternatively, the pass at which the image is acquired may be selected randomly or based on a specific criterion indicating, for example, the pass number at which the image should be acquired.

[0084] The comparison is performed by comparing the image acquired of the new part with the image included in the template corresponding to the same pass number. Advantageously, such a comparison enables the comparison of images of two parts acquired simultaneously during their manufacturing process.

[0085] The comparison can be performed by superimposing the image of the new part on the corresponding image of the template.

[0086] Preferably, in case the template comprises a set of minimum inner contours 301a, the image of the new part is compared with the minimum inner contours 301a of the template corresponding to the same pass number.

[0087] Then, step 107 is the step of verifying the dimensional compliance of the newly manufactured component.

[0088] The compliance of the new component is determined based on the comparison performed in comparison step 106 .

[0089] Preferably, a new component is defined as compliant if its thermal image adheres to the constraints defined by the minimum inner contour 301a of the template.

[0090] Herein, with respect to the internal cavity of the blade, if the internal cavity of the new component in the associated thermal image is larger than the minimum inner contour 301a included in the template, the new component is checked as having compliance. In other words, when the minimum inner contour 301a of the template is partially or completely larger than the internal cavity of the new component in the thermal image, the new component is defined as non-compliant. The internal cavity size of the new component exceeds the reference template.

[0091] Finally, if the new component is found to be non-compliant in step 107 for checking compliance, step 108 is a step of stopping the manufacture of the new component. This has the advantage that the manufacture of the component whose non-compliance is detected can be stopped early during the manufacture of the component. This advantageously reduces the amount of powder lost during the manufacture of the new non-compliant component. Another advantage is that the time spent on manufacturing the new non-compliant component is reduced and the manufacture of another new component is triggered, for example. This is particularly advantageous within the scope of mass production of components.

[0092] Stopping manufacturing can be performed manually by an operator, in which case step 108 is a step of issuing a non-compliance alarm for the new part being manufactured. The alarm can then be an audible or visual message indicating that the new part is non-compliant.

[0093] Stopping the production can be performed automatically by modifying the control parameters of the machine 10. "Control parameters" refer to the parameters of the machine 10 that are capable of controlling the production of the component. These parameters include parameters for controlling the scanner 11, the laser 14, the dichroic mirror 12 or the photodiode 13, etc. In this case, the control parameters can be modified by instructions stored in the memory of the computer controlling the machine 10 to stop the production of the new component. Thus, the control parameters are modified on the fly during the process of manufacturing the new component.

[0094] The method 100 according to the invention is compatible with several alternatives.

[0095] According to an alternative, the image of the reference component thermally acquired in the acquisition step 101 further comprises an outer contour 302 of the reference component. In the image, the outer contour 302 delimits the outer periphery of the component.

[0096] Preferably, the manufactured reference component is designed so that the outer perimeter of the component or other characteristic dimension of its external geometry is equal to the maximum perimeter of the external geometry allowed by the specification.

[0097] In this alternative, the reference template determined in the determination step 104 and comprising the minimum inner contour 301a also comprises the maximum outer contour 302b determined in each of a set of thermally acquired images of the reference component. These maximum outer contours 302b are determined by the same contour detection operation as that for the minimum inner contour 301a. Thus, the template comprises the maximum admissible outer contour 302b of the reference component at each moment of manufacture. In this case, the template always takes into account the thermal expansion of the component during manufacture.

[0098] In step 106 of comparing the thermal image acquired for the new part with the reference template, the image is compared with the minimum inner contour 301a and the maximum outer contour 302b corresponding to the same pass number.

[0099] In the step 107 of checking the compliance of the new component, the compliance of the new component is also evaluated based on the comparison of the thermal image of the new component with the maximum outer contour 320b. Herein, with respect to the outer geometry of the blade, the component is checked as having compliance if the outer geometry of the new component in the associated thermal image is smaller than the entire maximum outer contour 302b included in the template. In other words, when the maximum outer contour 302b of the template is partially or completely smaller than the outer geometry of the new component in the thermal image, the new component is defined as non-compliant. The outer dimensions of the component then exceed the reference template.

[0100] According to an alternative that is compatible with the previous alternative, the step 101 of acquiring a thermal image of a reference component also comprises acquiring a thermal image of a second reference component.

[0101] The second reference component is designed so that the internal cavity has the maximum size allowed by the specification. For example, the component is designed so that the perimeter of its internal cavity or other characteristic dimensions of the cavity are equal to the maximum perimeter of the cavity allowed by the specification.

[0102] Additionally, the second reference component may be designed such that the outer perimeter of the component or other characteristic dimension of its exterior geometry is equal to the minimum perimeter of the exterior geometry allowed by the specification.

[0103] The measuring step 102 also includes measuring the dimensions of the second reference component in the same manner as the reference component. In this case, the dimensions of the second reference component are measured cold. For example, in the case of a blade, the internal dimensions of the cavity are measured, such as its length, width, height and perimeter. Alternatively, the external dimensions of the blade are measured, such as the external length, width, height and perimeter of the component. As with the reference component, these measurements can be made by non-destructive inspection techniques (e.g., by infrared or X-ray imaging), or by destructive inspection (e.g., by sectioning the component).

[0104] The step 103 of verifying compliance also includes verifying compliance of the second reference component. The compliance is evaluated by comparing the cold measured dimensions of the second reference component with the dimensions specified by the specification. If the cold measured dimensions are consistent with the dimensions specified in the specification, the second reference component is defined as compliant. For example, if a certain dimension is less than or greater than a predetermined threshold, or is within a predetermined tolerance interval, the dimension is provided. In this article, if the internal cavity dimensions of the reference blade are consistent with the dimensions of the cavity specified by the specification, the reference blade is defined as compliant.

[0105] Then, the template determined in the template determination step 104 includes a set of thermal images of the reference component defined as compliant and a set of thermal images of the second reference component defined as compliant. Preferably, the template includes the contour 300 determined by contour detection in a set of thermal images of the reference component, and also includes the contour 300 determined by the same operation in a set of thermal images of the second reference component. Therefore, the template also includes the maximum inner contour 301b and the minimum outer contour 302a allowed for the reference component at each moment of manufacturing, obtained from a set of thermal images of the second reference component. Likewise, the template takes into account the thermal expansion of the component during manufacturing.

[0106] Therefore, in step 106 of comparing the thermal image of the new part with the reference template, the thermal image is compared with the minimum inner contour 301a and the maximum inner contour 301b and the minimum outer contour 302a and the maximum outer contour 302b corresponding to the same pass number.

[0107] Therefore, in the step 107 of verifying the compliance of the new component, the compliance of the new component is also evaluated based on a comparison of the image of the new hot component with the maximum inner contour 302b and the minimum outer contour 302a.

[0108] Regarding the internal cavity of the blade, if the internal cavity of the new component in the associated thermal image is larger than the minimum inner contour 301a and smaller than the maximum inner contour 301b included in the reference template, the new component is checked as having compliance. In other words, when the minimum inner contour 301a of the template is partially or completely larger than the internal cavity of the new component in the thermal acquisition image and / or when the maximum inner contour 301b of the template is partially or completely smaller than the internal cavity of the new component in the thermal acquisition image, the new component is defined as non-compliant. The internal cavity size of the new component exceeds the reference template.

[0109] With regard to the outer geometry of the blade, if the outer geometry of the new component in the associated thermal image is smaller than the entire maximum outer contour 302b included in the template and larger than the entire minimum outer contour 302a, the component is checked as having compliance. In other words, when the maximum outer contour 302b of the template is partially or completely smaller than the outer geometry of the new component in the thermal image and / or when the minimum outer contour 302a of the template is partially or completely larger than the outer geometry of the new component in the thermal acquisition image, the new component is defined as non-compliant. The outer dimensions of the new component then exceed the reference template.

[0110] According to an alternative compatible with the aforementioned alternative, the thermal image acquisition step 101 comprises acquiring thermal images of a plurality of reference components. That is, a thermal image of each reference component is acquired after melting each pass of the deposited powder. Optionally, the image may be an image of several reference components of the plurality of reference components, or an image of all reference components of the plurality of reference components. The advantage of using a plurality of reference components is having reference components of different ranges and a set of associated thermal images.

[0111] These reference components may be designed such that their internal and external dimensions (ie, the internal cavity dimensions and external geometry of the blade) meet the dimensional requirements of the component as described in the specification.

[0112] Thus, a step of measuring 102 and a step of verifying compliance 103 are performed on each of the plurality of reference components.

[0113] Therefore, the template determined in step 104 can be determined based on the reference components among the plurality of reference components that are verified to have compliance. In this case, it can be determined which compliant reference components have extreme internal and external dimensions. Then it can be determined that:

[0114] - a reference component having a smallest internal cavity size among the plurality of reference components;

[0115] - a reference component with the largest internal cavity size among the plurality of reference components;

[0116] - a reference component having the smallest external geometric dimensions among the plurality of reference components;

[0117] - A reference component having the largest external geometric dimension among the plurality of reference components.

[0118] Alternatively, the same reference component may have an extreme internal cavity size and an extreme external geometry size. Thus, the template may be determined from multiple sets of images of two, three or four different reference components having extreme sizes.

[0119] Advantageously, the template can be determined from the contour 300 obtained by the contour detection operation mentioned above. In this case, contour detection can be applied to each of the two, three or four groups of images of the reference part with extreme dimensions. This has the advantage of determining:

[0120] - the smallest inner contour 301a of each thermal image associated with the reference component with the smallest internal cavity size;

[0121] - the maximum inner contour 301b of each thermal image associated with the reference component with the largest internal cavity size;

[0122] - the smallest outer contour 302a of each thermal image associated with the reference component having the smallest outer geometrical dimensions;

[0123] - The largest outer contour 302b of each thermal image associated with the reference component having the largest outer geometrical dimensions.

[0124] This contour determination operation enables determination of a set of a minimum inner contour 301 a and a maximum inner contour 301 b and a minimum outer contour 302 a and a maximum outer contour 302 b .

[0125] The template then comprises a set of minimum inner contours 301a and maximum inner contours 301b and minimum outer contours 302a and maximum outer contours 302b derived from thermal images in the sets of images of reference components of extreme dimensions.

[0126] According to an alternative that is compatible with the previous alternative, it can be determined that:

[0127] - at least two reference components having the smallest internal cavity size among the plurality of reference components;

[0128] - at least two reference components of the plurality of reference components having the largest internal cavity size;

[0129] - at least two reference components having the smallest external geometric dimensions among the plurality of reference components;

[0130] - at least two reference components of the plurality of reference components having the largest external geometric dimensions.

[0131] An advantage is that there are at least two reference components for each limit and the profiles 300 determined from the thermal images of these reference components are averaged.

[0132] The at least two components may be determined based on an interval or threshold of an extreme internal dimension and an extreme external dimension. That is, if the internal dimension and / or the external dimension of the reference component is greater than or less than one or more predetermined extreme thresholds of each dimension, or if these dimensions are within one or more predetermined extreme intervals, the reference component may be considered to have an extreme internal dimension and / or an extreme external dimension. These predetermined extreme thresholds and / or predetermined extreme intervals may be defined based on specification requirements.

[0133] Once the reference components including the extreme sizes have been determined, one or more profiles 300 may be determined for each thermal image in each set of images for each reference component having the extreme sizes, thereby obtaining the following:

[0134] - the smallest inner contour 301a of each thermal image associated with the reference component with the smallest internal cavity size;

[0135] - the maximum inner contour 301b of each thermal image associated with the reference component with the largest internal cavity size;

[0136] - the smallest outer contour 302a of each thermal image associated with the reference component having the smallest outer geometrical dimensions;

[0137] - The largest outer contour 302b of each thermal image associated with the reference component having the largest outer geometrical dimensions.

[0138] In this case, the same type of contours 300 of the images acquired at the same moment in the manufacturing process can be averaged. In other words, after melting a given pass, the minimum inner contour 301a and the maximum inner contour 301b determined in the thermal image associated with this pass are averaged together, respectively. The minimum outer contour 302a and the maximum outer contour 302b determined in the thermal image associated with this pass are also averaged together, respectively. The reference template is then an average reference template, which includes the average extreme contours of the internal cavity and the external geometry of a plurality of reference parts with extreme dimensions.

[0139] According to an alternative compatible with the aforementioned alternative, the acquisition step 105 comprises acquiring a plurality of thermal images of the new part being manufactured. The acquired plurality of images can then be compared with the reference template in the same manner as in the case of a single image, by ensuring that the thermal image of the new part is compared with a thermal image or profile 300 associated with the same manufacturing time (i.e. the same pass number). The new part can then be monitored throughout its manufacturing process and any non-compliance occurring during manufacturing can be detected.

[0140] According to an alternative compatible with the above alternative, steps 105 to 108 according to method 100 can be carried out for a plurality of new components. Advantageously, within the scope of mass production of new components, the time required for inspection and manufacturing is accelerated and the number of components manufactured per batch is optimized.

[0141] In this alternative, the image acquired in step 105 may be an image of all of the plurality of new parts. Alternatively, after each pass of melting, several thermal images may be acquired, each thermal image being an image of at least one of the plurality of new parts. Preferably, each new part is imaged by a single image to avoid redundancy.

[0142] Therefore, the comparison step 106 and the compliance checking step 107 are performed on each of the plurality of new components to determine one or more new components that are checked as not having compliance.

[0143] In addition, in the stop manufacturing step 108, only the manufacturing of the new one or more non-compliant parts is stopped, and the manufacturing of the parts that are verified to be compliant is continued. In this case, for example, after issuing an audible or visual non-compliant alarm including identification of the new non-compliant part, the operator manually modifies the machine control parameters to stop manufacturing the part; or alternatively, the instructions included in the memory of the control computer are adjusted to automatically modify the control parameters and stop manufacturing the new non-compliant part.

[0144] Each set of thermal images or profiles 300 included in the template can be considered as the manufacturing history of the reference part with which it is associated. Therefore, by comparing the thermal images of the new part to the template, this history can be used to predict the future growth of the part being manufactured. Herein, through this comparison, deviations when growing the part by successive additions of material can be determined. Therefore, it can be determined whether the part deviates from the known growth pattern and may cause non-compliance.

[0145] Thus, step 108 may be a step of modifying parameters for controlling the additive manufacturing machine 10 .

[0146] Step 108 may first detect a deviation in the growth of the new part. For example, the deviation may be detected based on a deviation from the growth history of one or more reference parts contained in the template. The deviation may be quantified by a difference or similarity (e.g., by correlation) between one or more thermal images or profiles 300 of the reference template and the thermal image of the new part. In the event that the deviation is significant, such as when the deviation is greater than a certain threshold defined by a particular requirement or analysis of the manufacturing history of the reference parts, an action is triggered to modify the parameters controlling the machine 10 for manufacturing the part.

[0147] The parameters controlling the machine 10 are then modified (e.g. by compensating for the detected significant deviation) in order to avoid the new component becoming non-compliant during its manufacture. Thus, the control parameters are modified on the fly during the manufacturing process of the new component. The control parameters may be modified automatically using instructions stored in a memory of the control computer of the machine 10. Alternatively, the modification may be performed manually by an operator, and in this case step 108 is a step of issuing an alarm containing information about the significant deviation of the new component and information for identifying the new component (especially if several components are manufactured simultaneously). Advantageously, modifying the control parameters does not affect the manufacture of any other new components manufactured in parallel with the new component in the machine 10.

[0148] In addition, significant deviations can be detected based on the history of non-compliant reference parts. Thus, when the growth of a new part becomes close to or similar to the growth in the history of a non-compliant reference part, it can be detected that the growth of the new part has significantly deviated during its manufacture. Similarly, the closeness or similarity of the growth can be assessed by the deviation between the growth of the new part and the history of one or more non-compliant parts. For example, the deviation can be quantified by the difference or similarity (e.g., by correlation) between one or more thermal images or profiles 300 of the reference template and the thermal image of the new part. For example, the deviation is significant when the closeness or similarity is greater than a certain threshold defined by a specific requirement or analysis of the manufacturing history of the reference part.

[0149] In addition, the thermal image history of a new part that has already been manufactured and whose compliance has been evaluated can be used to predict the compliance of another new part that is being manufactured. The prediction is then implemented in the same manner as for the compliant reference part and the non-compliant reference part, as described in this alternative.

Claims

1. A method (100) for dimensional inspection of at least one component manufactured by an additive manufacturing machine (10), the additive manufacturing being performed by successive depositions of a powder bed (16) and melting the powder bed (16) after each deposition, the method (100) comprising the following steps: - a step (105) of acquiring an image of the part being manufactured after at least one step of depositing and melting a powder bed (16); - a step (106) of comparing the image with an image of a reference template, the reference template being obtained from a reference component to correspond to a first set of images acquired when manufacturing the reference component, the reference template comprising the first set of images, the acquired images of the first set of images comprising a minimum inner contour (301a) and / or a minimum outer contour (302a); - A step of checking the dimensional compliance of said component based on said comparison (107).

2. The method (100) according to the preceding claim, wherein: The acquisition step (105) is performed by a metal oxide semiconductor (CMOS) sensor camera or a charge coupled device (CCD) sensor camera arranged in the machine (10).

3. The method (100) according to any one of the preceding claims, wherein: Each acquired image includes an inner contour (301) and / or an outer contour (302) of the component being manufactured, the inner contour (301) defining the perimeter of an interior space of the component in the image, and the outer contour (302) defining the outer perimeter of the component in the image.

4. The method (100) according to any one of the preceding claims, wherein: The reference template is obtained after the following steps: - a step (101) of acquiring an image after each step of depositing and melting a powder bed (16) when manufacturing said reference part; - a step (102) of measuring the dimensions of said reference component after manufacturing said reference component; - a step (103) of verifying the compliance of said reference component by comparing said dimensions of said component with those provided by a specification; The reference template includes the first set of acquired images of the reference component that is inspected for compliance.

5. The method (100) according to the preceding claim, wherein: Measuring the dimensions of the reference component after manufacturing the reference component is accomplished by X-ray or sectioning.

6. The method (100) according to the preceding claim, wherein: The reference template is obtained from a plurality of reference parts, each reference part that is inspected to meet specifications is associated with a set of acquired images of the part, the reference template comprising the plurality of acquired sets of images.

7. The method (100) according to the preceding claim, wherein: The reference template is obtained from at least two reference components to correspond to a first group of images and a second group of images acquired respectively, wherein the acquired images in the first group of images include the minimum inner contour (301a) and / or the minimum outer contour (302a), and the acquired images in the second group of images include the maximum inner contour (301b) and / or the maximum outer contour (302b).

8. The method (100) according to claim 6 or 7, wherein: The reference template is obtained from an average value between the contours (301, 302) of a plurality of sets of images of each reference component.

9. The method (100) according to any one of the preceding claims, wherein: The reference template comprises at least one set of images of at least one reference component, and the method (100) further comprises the step of superimposing the image of the reference template on the acquired image after each image acquisition step (150).

10. The method (100) according to any one of the preceding claims, comprising the step (108) of stopping manufacturing and / or modifying the parameters of the additive manufacturing machine if the part being manufactured does not have dimensional compliance.

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