Blind area free flexible probe containing eddy current array and piezoelectric ultrasonic array and manufacturing method

Abstract

The application discloses a blind area-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array, which comprises a bottom plate, wherein the bottom plate is internally fixed with a sound head; the bottom plate is made of a flexible high polymer material; the sound head comprises, from bottom to top, a backing layer, a piezoelectric composite wafer and a first matching layer; both sides of the sound head on the bottom plate are provided with eddy current coils; the piezoelectric composite wafer is electrically connected with a first FPC soft circuit board; the eddy current coils are electrically connected with a second FPC soft circuit board; the first FPC soft circuit board and the second FPC soft circuit board are connected with an external cable through an adapter plate; and the upper surface of the bottom plate is covered with a second matching layer. A preparation method of the blind area-free flexible probe comprises the following steps in sequence: bottom plate manufacturing, layering manufacturing, sound head manufacturing, sound head installation, eddy current coil installation, connection adapter plate and second matching layer bonding. The blind area-free flexible probe has the advantages of reasonable structure, convenient preparation, irregular curved surface coupling, and improved defect detection success rate.

Description

Technical Field

[0001] This invention relates to the field of nondestructive testing technology, specifically to a blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array, and its fabrication method. Background Technology

[0002] During the forming process of general pipes or bars, defects such as pores, cracks, and inclusions are always generated. Moreover, the distribution of these defects is generally disordered, occurring at various locations from the surface to the bottom of the steel bar or pipe. This poses a huge challenge to conventional non-destructive testing probes, including contact single-crystal or dual-crystal ultrasonic probes, as existing probes are prone to missing detections. Summary of the Invention

[0003] The purpose of this invention is to overcome the above-mentioned deficiencies and to disclose to the public a blind-zone-free flexible probe containing eddy current arrays and piezoelectric ultrasonic arrays, which has a reasonable structure, is easy to prepare, can couple irregular curved surfaces, and improves the success rate of defect detection, as well as its manufacturing method.

[0004] The technical solution of this invention is implemented as follows: A blind-zone-free flexible probe comprising an eddy current array and a piezoelectric ultrasonic array includes a base plate, within which an acoustic head is fixed. The base plate is made of a flexible polymer material. The acoustic head, from bottom to top, includes a backing layer, a piezoelectric composite wafer, and a first matching layer. Eddy current coils are disposed on both sides of the acoustic head on the base plate. The piezoelectric composite wafer is electrically connected to a first FPC flexible circuit board, and the eddy current coils are electrically connected to a second FPC flexible circuit board. The first and second FPC flexible circuit boards are connected to an external cable via an adapter plate. The upper surface of the base plate is covered with a second matching layer.

[0005] Further optimization measures for this technical solution are as follows: As an improvement, the piezoelectric composite wafer includes a piezoelectric ceramic sheet, wherein an upper electrode layer and a lower electrode layer are respectively formed on the upper and lower surfaces of the piezoelectric ceramic sheet.

[0006] As an improvement, the upper and lower electrode layers of the piezoelectric ceramic sheet are formed by magnetron sputtering.

[0007] As an improvement, the upper electrode layer includes an upper electrode nickel-chromium layer and an upper electrode gold layer, and the lower electrode layer includes a lower electrode nickel-chromium layer and a lower electrode gold layer.

[0008] As an improvement, the eddy current coils are buried at the same depth in the longitudinal direction, and they are alternately arranged in the transverse position along the axial direction.

[0009] As an improvement, the base plate is provided with an axially arranged head fixing groove, and the base plate is also provided with an eddy current coil fixing hole.

[0010] As an improvement, the external cable is provided with a protective sleeve.

[0011] A method for fabricating a blind-zone-free flexible probe incorporating an eddy current array and a piezoelectric ultrasonic array includes the following steps: Step 1: Base plate fabrication: The base plate is made by casting and processing flexible polymer material, and the sound head fixing groove and eddy current coil fixing hole are integrally formed. Step 2, Lamination Fabrication: Inorganic powder material is sintered by high-temperature sintering material, and then cut, ground, and scribed into the designed size to produce piezoelectric ceramic sheets. The upper and lower surfaces of the piezoelectric ceramic sheets are made into upper and lower electrode layers by magnetron sputtering process. The first matching layer is then bonded to the upper electrode layer to obtain the laminate. Step 3, Sound Head Fabrication: The stacked layers are fixed with a tooling fixture, and then the fixed stacked layers are cut into 64 array elements of the same size by a dicing machine. After dicing, epoxy resin is poured into the cut seams and cured. After connecting the first FPC flexible circuit board, it is fixed with a tooling fixture. Backing material is poured into the backing mold in the tooling fixture and transferred to an oven for curing to obtain the backing layer, thus producing the sound head. Step 4, Sound Head Installation: Apply a nano-silicone rubber coating with adhesive properties to the four walls and bottom of the sound head fixing groove on the base plate. Then install the sound head obtained in Step 3 into the sound head fixing groove. After the nano-silicone rubber has bonded and cured, the sound head installation is complete. Step 5: Eddy current coil installation: Install each eddy current coil into the eddy current coil fixing hole on the base plate, add nano silicone rubber to the hole to cure and fix the eddy current coil, and electrically connect each eddy current coil to the second FPC flexible circuit board. Step 6: Connect the adapter board: After connecting the first FPC flexible circuit board and the second FPC flexible circuit board to the adapter board, connect them to the external cable. Step 7: Bonding the second matching layer: The second matching layer is bonded to the upper surface of the base plate using a nano-silicone rubber coating to obtain the probe.

[0012] In step two, the piezoelectric ceramic sheet is installed into a magnetron sputtering vacuum furnace using a tooling fixture. First, a nickel-chromium target is installed, and an upper electrode nickel-chromium layer and a lower electrode nickel-chromium layer are formed on the surface of the piezoelectric ceramic sheet using a magnetron sputtering process. Then, a gold target is switched, and an upper electrode gold layer and a lower electrode gold layer are formed on the outside of the upper electrode nickel-chromium layer and the lower electrode nickel-chromium layer using a magnetron sputtering process.

[0013] The eddy current coil is made of copper core wire with a transparent insulation layer and a core wire marked 42AWG, wound according to the design requirements for the number of turns and the winding diameter.

[0014] The advantages of this invention compared to the prior art are: The probe of this invention has a reasonable structure and is easy to manufacture. It integrates an eddy current array and a piezoelectric ultrasonic array, which can effectively detect both near-surface and far-surface defects, thereby effectively improving the success rate of defect detection. Its base plate is made of flexible polymer material, and the probe is ultimately a flexible structure that can couple with irregular curved surfaces, greatly improving the convenience of detection. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram of an embodiment of the present invention; Figure 2 This is a cross-sectional structural diagram of an embodiment of the present invention; Figure 3 yes Figure 2 A partially enlarged view of the medium-voltage electro-hydraulic composite wafer; Figure 4 yes Figure 2 Top view of the midsole plate; Figure 5 This is a schematic diagram illustrating the application of the flexible probe of the present invention.

[0016] The names of the reference numerals in the accompanying drawings of this invention are: 1. Base plate, 1a. Head fixing groove, 1b. Eddy current coil fixing hole, 2. Backing layer, 3. Piezoelectric composite wafer, 31. Piezoelectric ceramic sheet, 32. Upper electrode layer, 32a. Upper electrode nickel-chromium layer, 32b. Lower electrode layer, 33a. Lower electrode nickel-chromium layer, 33b. Lower electrode gold layer, 33b. First matching layer, 4. Eddy current coil, 5. First FPC flexible circuit board, 61. Second FPC flexible circuit board, 62. Adapter board, 63. External cable, 64. Cable sheath, 64a. Second matching layer, 7. Test piece, 8. Near surface defect, 81. Far surface defect, 82. Non-destructive testing equipment, 9. Ultrasonic display panel, 91. Eddy current display panel, 92. Ultrasonic operation panel, 93. Eddy current operation panel, 94. Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings: like Figures 1 to 4 As shown, a blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array includes a base plate 1, in which an acoustic head is fixed. The base plate 1 is made of a flexible polymer material. The acoustic head includes, from bottom to top, a backing layer 2, a piezoelectric composite wafer 3, and a first matching layer 4. Eddy current coils 5 are arranged on both sides of the acoustic head on the base plate 1. The piezoelectric composite wafer 3 is electrically connected to a first FPC flexible circuit board 61, and the eddy current coils 5 are electrically connected to a second FPC flexible circuit board 62. The first FPC flexible circuit board 61 and the second FPC flexible circuit board 62 are connected to an external cable 64 via an adapter plate 63. The upper surface of the base plate 1 is covered with a second matching layer 7.

[0018] The piezoelectric composite wafer 3 includes a piezoelectric ceramic sheet 31, and an upper electrode layer 32 and a lower electrode layer 33 are respectively formed on the upper and lower surfaces of the piezoelectric ceramic sheet 31.

[0019] The upper and lower electrode layers 32 and 33 of the piezoelectric ceramic sheet 31 are formed by magnetron sputtering.

[0020] The upper electrode layer 32 includes an upper electrode nickel-chromium layer 32a and an upper electrode gold layer 32b, and the lower electrode layer 33 includes a lower electrode nickel-chromium layer 33a and a lower electrode gold layer 33b.

[0021] The eddy current coils 5 are buried at the same depth in the longitudinal direction, and they are alternately arranged in the transverse position along the axial direction.

[0022] The base plate 1 is provided with an axially arranged head fixing groove 1a, and the base plate 1 is also provided with an eddy current coil fixing hole 1b.

[0023] The external cable 64 is provided with a protective sleeve 64a.

[0024] A method for fabricating a blind-zone-free flexible probe incorporating an eddy current array and a piezoelectric ultrasonic array includes the following steps: Step 1: Fabrication of Base Plate 1: Base Plate 1 is manufactured by casting flexible polymer material, and the acoustic head fixing groove 1a and eddy current coil fixing hole 1b are integrally formed; that is, the acoustic head fixing groove 1a and eddy current coil fixing hole 1b are formed simultaneously during the molding of Base Plate 1, without the need for subsequent processing. The total thickness of Base Plate 1 is 3mm, the depth of the acoustic head fixing groove 1a is 2mm, and the depth of the eddy current coil fixing hole 1b is 1mm.

[0025] Step 2, Lamination Fabrication: Inorganic powder material is sintered at high temperature, then wire-cut, ground, and diced to the designed dimensions to form piezoelectric ceramic sheets 31. The upper and lower surfaces of the piezoelectric ceramic sheet 31 are then coated with an upper electrode layer 32 and a lower electrode layer 33 using magnetron sputtering. A first matching layer 4 is then bonded to the upper electrode layer 32 to obtain the laminate. The first matching layer 4 is made of an inorganic-organic composite material, and is ground to the designed thickness according to different applications.

[0026] When fabricating the upper electrode layer 32 and the lower electrode layer 33, the piezoelectric ceramic sheet 31 is installed into a magnetron sputtering vacuum furnace using a tooling fixture. First, a nickel-chromium target is installed, and the upper electrode nickel-chromium layer 32a and the lower electrode nickel-chromium layer 33a are formed on the surface of the piezoelectric ceramic sheet 31 by magnetron sputtering. Then, a gold target is switched, and the upper electrode gold layer 32b and the lower electrode gold layer 33b are formed on the outside of the upper electrode nickel-chromium layer 32a and the lower electrode nickel-chromium layer 33a by magnetron sputtering.

[0027] The thicknesses of the upper electrode nickel-chromium layer 32a, the lower electrode nickel-chromium layer 33a, the upper electrode gold layer 32b, and the lower electrode gold layer 33b are designed according to the requirements of the probe.

[0028] Step 3, Sound Head Fabrication: The stacked layers are fixed using a fixture, and then the fixed stacked layers are diced again using a dicing machine into 64 elements of the same size. After dicing, epoxy resin is poured into the dicing slits and cured to ensure that there is no short circuit or crosstalk between the elements. After connecting the first FPC flexible circuit board 61, it is fixed using a fixture. Backing material is poured into the backing mold in the fixture and transferred to an oven for curing to obtain backing layer 2, thus producing the sound head. During the dicing process, the dicing process must be controlled, and a fixed dicing depth is set to ensure that only the lower electrode layer 33 and the piezoelectric ceramic sheet 31 are cut through, without cutting through the upper electrode layer 32 and the first matching layer 4. The backing material is a liquid composite material with a certain viscosity, which is made by fully mixing epoxy resin, curing agent, accelerator, defoamer, diluent, non-polar oxide powder and metal powder in a certain proportion. The resulting backing layer 2 has a certain elasticity and has the function of absorbing sound waves.

[0029] Step 4, Sound Head Installation: Apply a nano-silicone rubber coating with adhesive function to the four walls and bottom of the sound head fixing groove 1a of the base plate 1, and then install the sound head obtained in Step 3 into the sound head fixing groove 1a. After the nano-silicone rubber is bonded and cured, the sound head installation is complete. Step 5: Installation of Eddy Current Coils 5: Install each eddy current coil 5 into the eddy current coil fixing hole 1b of the base plate 1, apply nano-silicone rubber to the hole to cure and fix the eddy current coil 5, and electrically connect each eddy current coil 5 to the second FPC flexible circuit board 62. The eddy current coil 5 is made of copper core wire with a transparent insulating layer and a core wire marked 42AWG, wound according to the design requirements for the number of turns and the winding diameter.

[0030] Step 6: Connect the adapter board 63: After connecting the first FPC flexible circuit board 61 and the second FPC flexible circuit board 62 to the adapter board 63, connect them to the external cable 64. The external cable 64 is a 68-core x 38AWG coaxial cable. The external cable 64 is covered with a cable sheath 64a to prevent the external cable 64 from being broken or damaged.

[0031] Step 7: Bonding the second matching layer 7: The second matching layer 7 is bonded to the upper surface of the base plate 1 using a nano-silicone rubber coating to obtain the probe. The second matching layer 7 is a flexible polymer film with a certain thickness, designed according to the probe requirements. The second matching layer 7 covers each eddy current coil 5 to protect the eddy current coil 5.

[0032] like Figure 5The diagram shows the application of the flexible probe of the present invention. The shaded area represents the flexible probe. The test specimen 8 has an irregular curved surface. Due to the flexible structure of the probe, it can couple well with the irregular curved surface. The test specimen 8 has near-surface defects 81 and far-surface defects 82. The external cable 64 of the flexible probe is connected to the connection socket of the non-destructive testing equipment 9. The non-destructive testing equipment 9 is equipped with an ultrasonic display panel 91, an eddy current display panel 92, an ultrasonic operation panel 93, and an eddy current operation panel 94. By adjusting the gain knobs on the ultrasonic operation panel 93 and the eddy current operation panel 94, the ultrasonic display panel 91 and the eddy current display panel 92 can display good defect waveforms to accurately determine the defect location. The flexible probe of the present invention integrates an eddy current array and a piezoelectric ultrasonic array, which can effectively detect both near-surface defects 81 and far-surface defects 82, thereby effectively improving the success rate of defect detection.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A blind-zone-free flexible probe comprising an eddy current array and a piezoelectric ultrasonic array, comprising a base plate (1), wherein a sound head is fixed within the base plate (1), characterized in that: The base plate (1) is made of flexible polymer material. The sound head includes a backing layer (2), a piezoelectric composite chip (3) and a first matching layer (4) from bottom to top. Eddy current coils (5) are provided on both sides of the sound head on the base plate (1). The piezoelectric composite chip (3) is electrically connected to the first FPC flexible circuit board (61). The eddy current coils (5) are electrically connected to the second FPC flexible circuit board (62). The first FPC flexible circuit board (61) and the second FPC flexible circuit board (62) are connected to an external cable (64) via an adapter plate (63). The upper surface of the base plate (1) is covered with a second matching layer (7). The eddy current coils (5) are buried at the same depth in the longitudinal direction, and they are alternately arranged in the transverse position along the axial direction. The base plate (1) is provided with a sound head fixing groove (1a) axially, and the base plate (1) is also provided with an eddy current coil fixing hole (1b).

2. The blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 1, characterized in that: The piezoelectric composite wafer (3) includes a piezoelectric ceramic sheet (31), and the upper and lower surfaces of the piezoelectric ceramic sheet (31) are respectively provided with an upper electrode layer (32) and a lower electrode layer (33).

3. The blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 2, characterized in that: The upper and lower electrode layers (32 and 33) of the piezoelectric ceramic sheet (31) are formed by magnetron sputtering.

4. The blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 3, characterized in that: The upper electrode layer (32) includes an upper electrode nickel-chromium layer (32a) and an upper electrode gold layer (32b), and the lower electrode layer (33) includes a lower electrode nickel-chromium layer (33a) and a lower electrode gold layer (33b).

5. The blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 1, characterized in that: The external cable (64) is provided with a cable sheath (64a).

6. The method for fabricating a blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 5, characterized in that: Includes the following steps: Step 1, Fabrication of base plate (1): The base plate (1) is made by casting and processing flexible polymer material, and the sound head fixing groove (1a) and the eddy current coil fixing hole (1b) are integrally formed. Step 2, Stacking: Inorganic powder material is sintered by high temperature sintering material, and then cut into the design size by wire cutting, grinding and scribing to make piezoelectric ceramic sheet (31). The upper and lower surfaces of the piezoelectric ceramic sheet (31) are made into upper electrode layer (32) and lower electrode layer (33) by magnetron sputtering process. Then the first matching layer (4) is bonded to the upper electrode layer (32) to obtain the stack. Step 3, Sound Head Fabrication: The stack is fixed by a tooling fixture, and then the fixed stack is cut into 64 array elements of the same size by a dicing machine. After dicing, epoxy resin is injected into the cut and cured. After connecting the first FPC flexible circuit board (61), it is fixed by a tooling fixture. Backing material is poured into the backing mold in the tooling fixture and transferred to an oven to cure to obtain the backing layer (2), thus producing the sound head. Step 4, Sound head installation: Apply a nano-silicone rubber coating with adhesive function to the four walls and bottom of the sound head fixing groove (1a) of the base plate (1), and then install the sound head obtained in step 3 into the sound head fixing groove (1a). After the nano-silicone rubber is bonded and cured, the sound head installation is completed. Step 5, installation of eddy current coils (5): Install each eddy current coil (5) into the eddy current coil fixing hole (1b) of the base plate (1), add nano silicone rubber to the hole to cure and fix the eddy current coil (5), and electrically connect each eddy current coil (5) to the second FPC flexible circuit board (62). Step 6: Connect the adapter board (63): Connect the first FPC flexible circuit board (61) and the second FPC flexible circuit board (62) to the adapter board (63), and then connect them to the external cable (64). Step 7: Bond the second matching layer (7): Bond the second matching layer (7) to the upper surface of the base plate (1) through a nano silicone rubber coating to obtain the probe.

7. The method for fabricating a blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 6, characterized in that: In step two, the piezoelectric ceramic sheet (31) is installed into a magnetron sputtering vacuum furnace using a tooling fixture. First, a nickel-chromium target is installed, and an upper electrode nickel-chromium layer (32a) and a lower electrode nickel-chromium layer (33a) are formed on the surface of the piezoelectric ceramic sheet (31) by magnetron sputtering. Then, a gold target is switched, and an upper electrode gold layer (32b) and a lower electrode gold layer (33b) are formed on the outside of the upper electrode nickel-chromium layer (32a) and the lower electrode nickel-chromium layer (33a) by magnetron sputtering.

8. The method for fabricating a blind-zone-free flexible probe containing an eddy current array and a piezoelectric ultrasonic array according to claim 6, characterized in that: The eddy current coil (5) is made of copper core wire with a transparent insulation layer and a core wire marked 42AWG, wound according to the design requirements for the number of turns and the winding diameter.

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