Method for installing a control probe on an element to be controlled using at least one calibrated shim and equipment enabling the implementation of said method

Abstract

Method of placing a control probe on an element to be controlled using at least one calibrated wedge and equipment enabling the implementation of said method. The invention relates to a method of placing a control probe (34) on an element to be controlled (40), the method comprising a step of applying an adhesive (42.1) to couple the control probe (34) and the element to be controlled (40), a step of positioning the control probe (34) relative to the element to be controlled (40) and a step of polymerizing the adhesive (42.1). To obtain an optimal glue thickness (42.1) at the end of the polymerization step, at least one calibrated shim (46) is interposed between the control probe (34) and the element to be controlled (40), each calibrated shim (46) having a thickness substantially equal to an optimal value of the glue thickness (42.1), ensuring optimal coupling between the control probe (34) and the element to be controlled (40).The invention also relates to equipment for implementing said process. Figure 5.

Description

Title of the invention: Method of placing a control probe on an element to be controlled using at least one calibrated shim and equipment enabling the implementation of said method

[0001] The present application relates to a method of placing a control probe by waves on an element to be controlled using at least one calibrated shim as well as to equipment enabling the implementation of said method.

[0002] A non-destructive testing system can be used to inspect an element, such as an aircraft structure for example, in order to detect internal defects.

[0003] According to an embodiment visible in [Fig. 1], a non-destructive testing system 10 comprises a wave generator 12 and a control probe 14 connected to the wave generator 12 and configured to emit and receive waves 16. In operation, the control probe 14 is affixed to a surface S of an element to be tested 18 by interposing a coupling material 20 between the control probe 14 and the element to be tested 18 to optimize the transfer of waves 16 between the control probe 14 and the element to be tested 18.

[0004] When the control is to be carried out in real time, continuously or periodically, the control probe 14 must be glued to the element to be controlled 18 using an adhesive 20.1 which provides the functions of adhesive and coupling material 20.

[0005] According to one procedure, a first face 14.1 of the control probe 14, oriented towards the element to be controlled 18 in operation, is coated with a polymerizable adhesive 20.1. Generally, the area of ​​the surface S of the element to be controlled 18 to be covered by the control probe 14 is also coated with adhesive. Subsequently, the control probe 14 is pressed against the surface S of the element to be controlled 18. After polymerization of the adhesive 20.1, the control probe 14 is connected to the element to be controlled 18.

[0006] As long as the adhesive 20.1 is not fully polymerized, an operator holds the control probe 14 by applying pressure towards the part to be inspected 18 while keeping the first face 14.1 of the control probe 14 oriented towards the part to be inspected 18, substantially parallel to the surface S of the part to be inspected 18, attempting to maintain it at a predefined optimal distance for measurements. To accelerate polymerization, the adhesive can be heated.

[0007] This operating method is not satisfactory because the polymerization of the adhesive is not carried out under optimal and controlled conditions. Consequently, the adhesive may have a suboptimal thickness and / or defects, so that the measurements The measurements taken are not optimal. It would therefore be desirable to find a solution to improve the accuracy of the measurements taken.

[0008] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0009] To this end, the invention relates to a method of placing a control probe on a surface of an element to be controlled, the control probe being connected to the element to be controlled by a coupling material in the form of an adhesive configured to occupy a first state in which the adhesive can be applied and a second state, after a polymerization phase, in which the adhesive connects the control probe and the element to be controlled and has a thickness substantially equal to a coupling value to obtain optimal coupling between the control probe and the element to be controlled; the placement method comprising a step of applying the adhesive, a step of positioning the control probe relative to the element to be controlled and a step of polymerizing the adhesive.

[0010] According to the invention, the placement method includes a positioning step of at least one calibrated shim interposed between the control probe and the element to be controlled at least before the polymerization step, each calibrated shim having a thickness substantially equal to the optimum value of the thickness of the glue.

[0011] This process simplifies the installation of the control probe, optimizes installation time and provides optimal glue thickness and polymerization.

[0012] According to another feature, the positioning step of at least one calibrated wedge consists of inserting, between the control probe and the element to be controlled, two spaced and substantially parallel wires, each of which has a diameter equal to the optimal value of the thickness of the glue.

[0013] According to another characteristic, each calibrated shim has a thickness between 100 and 200 pm, and preferably equal to about 150 pm with a tolerance of + / -10%.

[0014] According to another feature, during at least part of the polymerization step, a calibrated force is applied to the control probe in the direction of the element to be controlled so that each calibrated shim is simultaneously in contact with the element to be controlled and the control probe.

[0015] According to another feature, the polymerization step is carried out under a regulated atmosphere.

[0016] According to another feature, the regulated atmosphere has an optimal regulated temperature for the polymerization step of the glue.

[0017] According to another feature, the control probe is positioned in an enclosure containing a regulated atmosphere during at least part of the polymerization step.

[0018] The invention also relates to equipment for implementing a method of installing a control probe according to one of the preceding characteristics. According to the invention, this equipment comprises a positioning tool that includes a housing configured to accommodate a control probe and at least one calibrated shim, connected to the positioning tool, configured to be interposed between the control probe and the element to be inspected.

[0019] According to another feature, the positioning tooling comprises a body which has first and second opposite faces, the housing opening at the level of the first and second faces and having a cross-section substantially identical to that of the control probe.

[0020] According to another feature, the positioning tooling comprises at least two spaced and substantially parallel wires, each forming a calibrated shim, connected to the body, passing through the housing and positioned at the level of the first face of the body.

[0021] According to another feature, the equipment includes a pressure system configured to apply a calibrated force to the control probe in the direction of the element to be controlled.

[0022] According to another feature, the pressure system includes at least one object of calibrated mass positioned on the control probe.

[0023] According to another feature, the equipment includes at least one heating system for heating the glue and / or a regulated atmosphere in which the glue is positioned.

[0024] According to another feature, the heating system is positioned in the body, near the first face of the body configured to be oriented towards the element to be controlled in operation.

[0025] According to another feature, the equipment includes at least one temperature sensor configured to measure the temperature of the glue and / or of a regulated atmosphere in which the glue is positioned in order to control the heating system.

[0026] According to another feature, the temperature sensor is positioned in the positioning tooling, near the first face of the body.

[0027] According to another feature, the equipment includes at least one enclosure sized to house the positioning tooling in which the control probe is positioned.

[0028] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which:

[0029] [Fig-1] is a schematic side view of a non-destructive testing system by waves and an element to be controlled illustrating a mode of realization of the prior art,

[0030] [Fig.2] is a schematic side view of a non-destructive testing system using waves and of an element to be tested illustrating an embodiment of the invention,

[0031] [Fig.3] is a schematic top view of the non-destructive testing system using waves and of the element to be tested visible in [Fig.2],

[0032] [Fig.4] is a schematic top view of a holding and polymerization device and a control probe illustrating one embodiment of the invention,

[0033] [Fig.5] is a schematic side view of a holding and polymerization device and a control probe illustrating one embodiment of the invention,

[0034] [Fig.6] is a top view of part of a positioning tool illustrating one embodiment of the invention,

[0035] [Fig.7] is a top view of a control probe positioned in the positioning tooling visible in [Fig.6],

[0036] [Fig.8] is a schematic representation of the different stages of a method for setting up a control probe illustrating one embodiment of the invention.

[0037] According to an embodiment visible in Figures 2 and 3, a non-destructive testing system 30 comprises a wave generator 32, a control probe 34 connected to the wave generator 32 and configured to emit and receive waves 36, and a processing unit 38 configured to process the signals emitted by the control probe 34. In operation, the control probe 34 is affixed to a surface S of an element to be tested 40 by interposing a coupling material 42 between the control probe 34 and the element to be tested 40 to optimize the transfer of waves 36 between the control probe 34 and the element to be tested 40.

[0038] According to one application, the element to be controlled 40 is a structure of an aircraft.

[0039] The control probe 34 includes a first face 34.1 oriented towards the element to be controlled 40 in operation. This first face 34.1 corresponds to the face of the control probe from which the waves 36 are emitted and received. This first face 34.1 is generally flat.

[0040] In one configuration, the control probe 34 is substantially parallelepiped-shaped. In a variant shown in [Fig. 7], the control probe 34 is substantially parallelepiped-shaped and has a first face 34.1 oriented towards the element to be controlled 40, a second face 34.2 opposite the first face 34.1, and faces Lateral faces 34.3 connect the first and second faces 34.1, 34.2, which are perpendicular in pairs, and chamfered edges 34.4, 34.4' are located at the junctions of the lateral faces 34.3. Depending on the configuration, the control probe 34 includes at least one keying feature. For example, a chamfered edge 34.4' larger than the other chamfered edges 34.4 can serve as a keying feature.

[0041] In a plane parallel to the first face 34.1, the control probe 34 has a cross-section.

[0042] According to one configuration, the wave generator 32 is an ultrasonic wave generator and the control probe 34 is a conventional or multi-element type ultrasonic probe.

[0043] The wave generator 32, the control probe 34 and the processing unit 38 are not described further as they are known to the person skilled in the art and can be identical to those of the prior art.

[0044] Depending on the application, when the control is to be carried out in real time, continuously or periodically for example, the control probe 34 is permanently connected to the element to be controlled 40 using an adhesive 42.1 which provides the functions of adhesive and coupling material 42.

[0045] This adhesive 42.1 is configured to have a paste or liquid, unhardened state, allowing its application as well as a hardened state allowing the control probe 34 and the element to be controlled 40 to be firmly connected. According to one embodiment, the adhesive 42.1 is a polymerizable adhesive and passes from the paste state to the hardened state during a polymerization step.

[0046] For the present application, polymerization means a step of transformation of the adhesive 42.1 from a first state in which it can be applied and a second state in which it firmly connects the control probe 34 and the element to be controlled 40.

[0047] As an example, glue 42.1 is chosen from the family of epoxy glues.

[0048] To optimize the mechanical bond and optimal transfer of the waves 36 between the control probe 34 and the element to be controlled 40, the adhesive 42.1 must, after the polymerization step, have a thickness (distance separating the surface S of the element to be controlled 40 and the first face 34.1 of the control probe 34) substantially equal to a coupling value. To give an order of magnitude, the coupling value is between 100 and 200 pm, and preferably is approximately 150 pm with a tolerance of + / - 10%. This coupling value may differ from one adhesive to another.

[0049] Depending on the area to be inspected of the element to be controlled 40, the control probe 34 is positioned on the surface S according to a given position and orientation.

[0050] A method for placing the control probe 34 on the surface S of the element to be controlled 40 includes a step of applying the adhesive 42.1 in an unpolymerized state between the control probe 34 and the surface S of the element to be controlled 40, a step of positioning the control probe 34 relative to the element to be controlled 40 according to the given position and orientation, and a step of polymerizing the adhesive 42.1 so that the control probe 34 is connected to the element to be controlled 40 and immobile relative to the latter.

[0051] According to one method, during the adhesive application step 42.1, at least one surface of the first face 34.1 of the control probe 34 and an area of ​​the surface S of the element to be inspected 40, for example, the area covered by the control probe 34, is coated with adhesive. In one configuration, the first face 34.1 of the control probe 34 and the area of ​​the surface S of the element to be inspected 40 are coated with adhesive, as illustrated in parts (B) and (C) of [Fig. 8]. In one embodiment, a stencil 44 is applied to the surface S prior to its coating with adhesive, as illustrated in part (B) of [Fig. 8].

[0052] Prior to the step of applying the glue 42.1, each surface to be glued is prepared in order to promote the adhesion of the glue 42.1.

[0053] According to a particular feature of the invention, the placement method includes a step of positioning at least one calibrated shim 46 interposed between the control probe 34 and the element to be controlled 40 at least before the polymerization step. This calibrated shim 46 has a thickness substantially equal to the coupling value of the thickness of the adhesive 42.1 to obtain optimal coupling. In one embodiment, each calibrated shim 46 has a thickness between 100 and 200 µm, and preferably about 150 µm with a tolerance of + / - 10%.

[0054] According to one arrangement, at least two calibrated shims 46 of the same thickness are interposed between the control probe 34 and the element to be controlled 40.

[0055] To avoid interfering with the measurements, each calibrated shim 46 is a wire. In this case, the positioning step of at least one calibrated shim 46 consists of inserting, between the control probe 34 and the element to be controlled 40, two spaced and substantially parallel wires, each having a diameter equal to the coupling value of the thickness of the adhesive 42.1 to obtain optimal coupling. According to one embodiment, each wire is a polyamide wire, in particular a transparent one.

[0056] During at least part of the polymerization step, a calibrated force 48 is applied to the control probe 34 in the direction of the element to be tested 40 so that each calibrated shim 46 is simultaneously in contact with the surface S of the element to be tested 40 and the control probe 34. This calibrated force 48 is applied until the adhesive 42.1 has hardened sufficiently for the control probe 34 to be stationary relative to the element to be tested 40. The calibrated force 48 is applied until the adhesive 42.1 has fully hardened, in particular until the adhesive 42.1 has completely polymerized.

[0057] According to one embodiment, at least one pressure system 50 is used to apply this calibrated force 48. In one embodiment, the pressure system 50 comprises at least one object of calibrated mass 50.1 positioned on the second face 34.2 of the control probe 34. This solution makes it possible to apply a calibrated force 48 when the second face 34.2 is substantially horizontal and oriented upwards. Of course, the invention is not limited to this solution for applying a calibrated force to the control probe 34 in the direction of the element to be controlled 40. Other mechanical systems for ensuring constant pressure on the control probe 34 could be used.

[0058] The combination of the calibrated wedge(s) and the calibrated force allows control of the thickness of the glue 42.1.

[0059] According to one configuration, the polymerization step is carried out under a controlled atmosphere configured to optimize the polymerization of the adhesive 42.1. This controlled atmosphere maintains an optimal temperature for the polymerization of the adhesive 42.1. Thus, during the polymerization step, the adhesive 42.1 is kept at a stable temperature with a value adapted to the adhesive 42.1 to optimize the polymerization process. The controlled temperature varies depending on the material of the adhesive 42.1.

[0060] Depending on a configuration, the regulated atmosphere has a regulated pressure or other regulated characteristics.

[0061] The regulated atmosphere is maintained for a determined time adapted to the glue 42.1 so that the latter is hardened or totally polymerized.

[0062] According to a configuration visible in [Fig. 2], [Fig. 4], and part (F) of [Fig. 8], to obtain a controlled atmosphere, the control probe 34 is positioned in a chamber 52 containing the controlled atmosphere for at least part of the polymerization step. In one embodiment, the chamber 52 comprises a face, pressed against the surface S of the element to be controlled 40, which has an opening 52.1 to allow the passage of the control probe 34.

[0063] According to an embodiment shown in [Fig. 4] and part (G) of [Fig. 8], at least one heating system 54 is provided for heating the glue 42.1 and / or the regulated atmosphere in which the glue 42.1 is positioned. According to an arrangement shown in [Fig. 4], the heating system is positioned at a distance from the control probe 34, outside the enclosure 52. According to this arrangement, an airflow generator 56 is provided for blowing the air heated by the heating system 54 into the enclosure 52.

[0064] According to another arrangement, the heating system 54 is positioned as close as possible to the glue 42.1 on at least part of the periphery of the control probe 34.

[0065] In addition to the heating system 54, at least one temperature sensor 58, such as a thermocouple for example, is configured to measure the temperature of the glue 42 and / or the regulated atmosphere in which the glue 42.1 is positioned in order to control the heating system 54 so that the glue 42.1 and / or the regulated atmosphere in which the glue 42.1 is positioned has a temperature substantially equal to a setpoint value allowing optimal polymerization of the glue 42.1. Thus, the combination of the heating system 54 and the temperature sensor 58 makes it possible to obtain a regulated temperature at the level of the glue 42.1 or in its vicinity.

[0066] According to one operating method, the step of positioning the control probe 34 according to the given position and orientation consists of making at least one marking 60 on the surface S of the element to be controlled 40, as illustrated in part (A) of [Fig.8], and positioning the control probe 34 with respect to the marking 60.

[0067] According to another operating method visible in Figures 6, 7 and parts (E) and (D) of [Fig.8], during the positioning step, the control probe 34 is positioned in a positioning tool 62 itself positioned relative to the marking 60 in order to position the control probe 34 according to the given position and orientation.

[0068] According to one embodiment, the positioning tool 62 comprises a body 64 having first and second opposing faces 64.1, 64.2 and a housing 66, configured to house the control probe 34, which opens at the first and second faces 64.1, 64.2 and has a cross-section (in a plane parallel to the first or second face 64.1, 64.2) substantially identical to that of the control probe 34. Thus, when the control probe 34 is positioned in the housing 66, it is perfectly immobilized relative to the positioning tool 62 in a plane parallel to the first or second face 64.1, 64.2. Thanks to its keying feature, the control probe 34 is immobilized relative to the positioning tool in a single orientation.Therefore, when the positioning tool 62 is correctly positioned relative to the marking 60 located on the surface S of the element to be controlled 40, the control probe 34 positioned in the positioning tool 62 is positioned according to the given position and orientation.

[0069] The body 64 can be metallic, plastic or composite material.

[0070] According to one embodiment, the positioning tooling 62 comprises a system heating element 54 positioned near the first face 64.1 of the body 64 which is pressed against the surface S of the element to be controlled 40 in operation, of preference on at least part of the perimeter of the housing 66. Thus, the heating system 54 is positioned as close as possible to the glue 42.1, allowing it to be heated by thermal diffusion in an optimal way.

[0071] According to one arrangement, the temperature sensor 58 is positioned in the positioning tooling 62 near the first face 64.1 of the body 64 to reliably measure the temperature of the glue 42.1.

[0072] According to one embodiment, the positioning tool 62 comprises at least one calibrated shim 46 connected to the body 64 and configured to be interposed between the control probe 34 and the element to be controlled 40. According to one arrangement, the positioning tool 62 comprises at least two wires substantially parallel to each other, each forming a calibrated shim 46, connected to the body 64, passing through the housing 66 and positioned at the level of the first face 64.1 of the body 64.

[0073] According to one embodiment, a holding and polymerizing equipment comprises at least one positioning tool 62 and optionally at least one enclosure 52 and / or at least one pressure system 50. This holding and polymerizing equipment can be used to implement a method for positioning a control probe 34. The enclosure 52 is dimensioned to house the positioning tool 62 in which the control probe 34 is positioned.

[0074] According to a procedure shown in [Fig. 1], this installation method comprises: a. a step of affixing at least one marking 60 to the surface S of the element to be controlled 40 as illustrated in part (A) of [Fig.8], said marking 60 being positioned according to the given position and orientation of the control probe 34, b. a step of applying the glue 42.1 by gluing an area of ​​the surface S of the element to be controlled 40, as illustrated in part (B) of [Fig.8], and the first face 34.1 of the control probe 34, as illustrated in part (C) of [Fig.8], c. a step of positioning the control probe 34 in the positioning tool 62 positioned according to the marking 60 on the surface S, as illustrated in Figures 6, 7 and parts (D) and (E) of [Fig.8], d. a step of positioning the pressure system 50 configured to exert a calibrated force on the control probe 34, as illustrated in [Fig.5], e. a step of setting up the enclosure 52 so that it covers the control probe 34, as illustrated in [Fig.4] and part (F) of [Fig.8], f. a polymerization step under a regulated atmosphere and for a given duration, as illustrated in figure (G) of [Fig.8].

[0075] Regardless of the operating method, the placement process allows for optimal glue thickness 42.1 and polymerization.

[0076] This process also simplifies the installation of the control probe and optimizes installation time.

Claims

Demands

1. A method for placing a control probe (34) on a surface (S) of a control element (40), the control probe (34) being connected to the control element (40) by a coupling material (42) in the form of an adhesive (42.1) configured to occupy a first state in which the adhesive (42.1) can be applied and a second state, after a polymerization phase, in which the adhesive (42.1) connects the control probe (34) and the control element (40) and has a thickness substantially equal to a coupling value to obtain optimal coupling between the control probe (34) and the control element (40); the placement method comprising a step of applying the adhesive (42.1), a step of positioning the control probe (34) relative to the control element (40), a step of polymerizing the adhesive (42.1).1) as well as a positioning step of at least one calibrated shim (46) interposed between the control probe (34) and the element to be controlled (40) at least before the polymerization step, each calibrated shim (46) having a thickness substantially equal to the optimum value of the thickness of the adhesive (42.1); characterized in that the positioning step of at least one calibrated shim (46) consists of interposing, between the control probe (34) and the element to be controlled (40), two spaced and substantially parallel wires which each have a diameter equal to the optimum value of the thickness of the adhesive (42.1).

2. Method of setting up a control probe (34) according to the preceding claim, characterized in that each calibrated shim (46) has a thickness between 100 and 200 pm, and preferably equal to about 150 pm with a tolerance of + / - 10%.

3. A method for setting up a control probe (34) according to any one of the preceding claims, characterized in that, during at least part of the polymerization step, a calibrated force (48) is applied to the control probe (34) in the direction of the element to be controlled (40) so that each calibrated shim (46) is simultaneously in contact with the element to be controlled (40) and the control probe (34).

4. Method of setting up a control probe (34) according to any one of the preceding claims, characterized in that the polymerization step is carried out under a regulated atmosphere.

5. Method of setting up a control probe (34) according to the preceding claim, characterized in that the regulated atmosphere has an optimal regulated temperature for the polymerization step of the glue (42.1).

6. Method of setting up a control probe (34) according to any one of the preceding claims, characterized in that the control probe (34) is positioned in an enclosure (52) containing a regulated atmosphere during at least part of the polymerization step.

7. Equipment for implementing a method for installing a control probe (34) according to any one of the preceding claims, characterized in that the equipment comprises a positioning tool (62) which includes: a. a housing (66) configured to house a control probe (34) and at least one calibrated shim (46), connected to the positioning tool (62), configured to be interposed between the control probe (34) and the element to be controlled (40), b. a body (64) which has first and second opposing faces (64.1, 64.2), the housing (66) opening at the level of the first and second faces (64.1, 64.2) and having a cross-section substantially identical to that of the control probe (34), and c. at least two spaced and substantially parallel wires, each forming a calibrated wedge (46), connected to the body (64), passing through the housing (66) and positioned at the level of the first face (64.1) of the body (64).

8. Equipment according to claim 7, characterized in that the equipment comprises a pressure system (50) configured to apply a calibrated force (48) on the control probe (34) in the direction of the element to be controlled (40).

9. Equipment according to the preceding claim characterized in that the pressure system (50) comprises at least one object of calibrated mass (50.1) positioned on the control probe (34).

10. Equipment according to any one of claims 7 to 9, characterized in that the equipment includes at least one heating system (54) for heating the glue (42.1) and / or a regulated atmosphere in which the glue (42.1) is positioned.

11. Equipment according to claims 7 and 10, characterized in that the heating system (54) is positioned in the body (64), near the first face (64.1) of the body (64) configured to be oriented towards the element to be controlled (40) in operation.

12. Equipment according to any one of claims 10 to 11, characterized in that the equipment includes at least one temperature sensor (58) configured to measure the temperature of the glue (42) and / or of a regulated atmosphere in which the glue (42.1) is positioned in order to control the heating system (54).

13. Equipment according to claims 11 and 12, characterized in that the temperature sensor (58) is positioned in the positioning tooling (62), near the first face (64.1) of the body (64).

14. Equipment according to any one of claims 7 to 13, characterized in that the equipment comprises at least one enclosure (52) dimensioned to house the positioning tooling (62) in which the control probe (34) is positioned.

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