Marine engine connecting rod industrial CT detection system, detection method and special tool

Abstract

A marine engine connecting rod industrial CT detection system is characterized by comprising a multi-axis motion detection machine tool (1) which comprises a Z1-axis lifting device (7), a Z2-axis lifting device (9), an X-axis moving device (12), a Y-axis moving device (11) and a C-axis rotating device (8), and all motion axes are controlled by a computer numerical control system; a dual-mode radiation source device comprises: an X-ray machine radiation source (6), the maximum power of which is 1500 W, the maximum voltage of which is 450 kV, and the minimum focus size of which is 0.4 mm; the energy range of the accelerator ray source (5) is 2-6 MeV; the digital flat panel detector (2) is used for receiving a ray signal penetrating through the workpiece and generating two-dimensional projection data; the adjustable connecting rod clamp device (3) is used for fixing connecting rods with different sizes and ensuring no vibration or displacement in the detection process; the radiation source fixing frame, the detector fixing frame and the part detection platform are fixed on the multi-axis motion detection machine tool (1) and are respectively used for placing the dual-mode radiation source device, the digital flat panel detector (2) and the adjustable connecting rod clamp device (3).

Description

Technical Field

[0001] The patent of this invention relates to the field of non-destructive testing, specifically to an industrial CT detection system, detection method and special tooling for a marine engine connecting rod. Background Art

[0002] With the rapid development of the shipbuilding industry, marine engines, as core components of ship propulsion systems, have become increasingly important. Their performance stability and reliability are directly related to the safe operation and economic benefits of ships. However, as key components that transmit power and withstand complex loads, marine engine connecting rods are susceptible to fatigue, corrosion, wear, and other factors during long-term operation, resulting in internal defects such as cracks, pores, and inclusions.

[0003] Traditional connecting rod inspection methods, such as visual inspection, tapping method, magnetic particle inspection, etc., have shortcomings such as low detection efficiency, poor sensitivity, and easy missed detection. They are difficult to meet the modern shipbuilding industry's demand for high-precision and high-efficiency inspection technology.

[0004] Industrial CT technology, with its high penetration and three-dimensional imaging capabilities, has shown significant advantages in the field of non-destructive testing. However, existing industrial CT inspection systems still have the following problems in the application of marine engine connecting rods:

[0005] Lack of adaptability: A single X-ray source cannot meet the inspection requirements of connecting rods of different sizes and thicknesses;

[0006] Fixed fixture defects: Traditional fixtures can easily block the ray path or introduce vibration, affecting imaging quality;

[0007] Low degree of automation: The scanning process relies on manual adjustments, making it difficult to balance efficiency and accuracy.

[0008] Based on this, the present invention proposes an industrial CT detection solution that combines a dual-ray source system, multi-axis motion control, and a special fixture design, aiming to solve the above technical bottlenecks and improve the accuracy, efficiency, and applicability of marine engine connecting rod defect detection. Summary of the Invention

[0009] The present invention aims to provide a system, method, and specialized tooling for inspecting connecting rods for marine engines. This method effectively improves inspection efficiency and accuracy, and makes it easier to identify internal defects in connecting rods. The designed specialized inspection fixture not only stabilizes the connecting rod, reducing vibration and displacement during inspection, but also features multi-dimensional adjustment, facilitating comprehensive and detailed inspection of the connecting rod.

[0010] The technical solutions of the present invention are as follows:

[0011] An industrial CT inspection system for connecting rods of marine engines, which is characterized by including

[0012] A multi-axis motion detection machine tool (1) includes a Z1-axis lifting device (7), a Z2-axis lifting device (9), an X-axis moving device (12), a Y-axis moving device (11) and a C-axis rotating device (8), wherein each motion axis is controlled by a computer numerical control system;

[0013] A dual-mode radiation source device comprises: an X-ray machine radiation source (6) with a maximum power of 1500W, a maximum voltage of 450kV, and a minimum focal spot size of 0.4mm; and an accelerator radiation source (5) with an energy range of 2-6MeV;

[0014] A digital flat panel detector (2) is used to receive the ray signal after penetrating the workpiece and generate two-dimensional projection data;

[0015] An adjustable connecting rod clamp device (3) for fixing connecting rods of different sizes to ensure no vibration or displacement during the test;

[0016] A ray source fixing frame, a detector fixing frame and a parts detection platform fixed on the multi-axis motion detection machine tool (1) are used to respectively place the dual-mode ray source device, the digital flat panel detector (2) and the adjustable connecting rod clamp device (3).

[0017] The entire machine tool is fixed to the ground. The Z1-axis lifting device 7, the Z2-axis lifting device 9, and the Y-axis moving device 11 are all mounted to the inspection machine body 1. The C-axis rotation device 8 is fixed to the platform of the X-axis moving device 12, and the X-axis moving device 12 is mounted to the flange platform of the Y-axis moving device 11. A detector mounting bracket 10 is mounted on the Z1-axis lifting device 7, which secures the digital flat-panel detector 2. A radiation source mounting bracket 13 is mounted on the Z2-axis lifting device, which secures the accelerator radiation source 5 and the X-ray machine radiation source 6. The entire radiation scanning device consists of these two radiation sources, the accelerator radiation source 5 and the X-ray machine radiation source 6, and the digital flat-panel detector 2.

[0018] The connecting rod inspection tool 3 is composed of a small-end chassis 14, a small-end clamping seat 15, a connecting rod part 16, a positive thread support rod 17, a hexagonal stud screw 18, a negative thread support rod 19, a large-end clamping seat 20, and a large-end chassis 21. The entire connecting rod inspection tool 3 is fixed to the part inspection platform 4 via a chassis locking assembly 22. The connecting rod part 16 is locked by the small-end clamping seat 15 and the large-end clamping seat 20 via the hexagonal stud screw 18, so that the upper and lower parts of the connecting rod part 16 are pulled and squeezed against each other until the connecting rod part 16 is fixed up and down. The small-end clamping seat 15 and the large-end clamping seat 20 both have threaded holes on the side to install set screws to lock the side of the part.

[0019] The detection machine tool body 1 and its moving device are structured as follows: consisting of a Z1-axis lifting device 7, a C-axis rotating device 8, a Z2-axis lifting device 9, a detector fixing frame 10, a Y-axis moving device 11, an X-axis moving device 12 and a radiation source fixing frame 13.

[0020] The connecting rod inspection tool 3 is structured as follows: it is composed of a small end chassis 14, a small end clamping seat 15, a connecting rod part 16, a positive thread support rod 17, a hexagonal double-headed screw 18, a negative thread support rod 19, a large end clamping seat 20 and a large end chassis 21.

[0021] The entire X-ray scanning device consists of two sets of radiation sources: an accelerator radiation source 5 and an X-ray machine radiation source 6, as well as a digital flat-panel detector 2. This is an existing technology. This detection platform can select different radiation sources for testing workpieces of different sizes and models. For smaller or thinner parts, the MXR-451HP / 11 X-ray machine radiation source 6 can be selected. Its maximum power is 1500W, and the high voltage can reach up to 450KV. The minimum focal length of this X-ray machine can be selected to be 0.4mm, which can obtain higher-definition imaging. For larger or thicker parts, if the X-ray machine cannot penetrate, the accelerator radiation source 5 can be selected for irradiation by adjusting the Z2-axis lifting device 9. Its model is a 2-6MeV linear accelerator. Both radiation beams can be scanned and imaged using the XRD1611 flat-panel detector.

[0022] The detection method using the above detection system has the following detection process:

[0023] (1) Workpiece installation stage: The small end chassis 14 and the small end clamping seat 15 are fixed by hexagon socket countersunk screws, while the other side is fixed by the large end clamping seat 20 and the large end chassis 21 by hexagon socket countersunk screws. The small end chassis 14 is fixed to the four positive thread support columns 17 by hexagon socket cylindrical head screws, while the large end chassis 21 is also fixed to the four negative thread support columns 19 by hexagon socket cylindrical head screws. At this point, the upper and lower fixed parts have been installed. Then, the upper and lower parts are connected by four hexagonal double-headed screws 18. Since the two ends of the hexagonal double-headed screws are positive and negative thread structures, they are installed correspondingly to the positive thread support rods 17 and negative thread support rods 19. During installation, the clamping of the fixed parts at both ends can be adjusted by tightening the screws. The small end clamping seat 15 and the large end clamping seat 20 have threaded holes on the side to install the set screws to lock the side of the parts. The entire tooling is fixed to the central area of the part detection platform 4 by the chassis locking assembly 22.

[0024] (2) Preparation of X-ray source and detector: Select a suitable X-ray source according to the size and thickness of the part, control the computer to drive the machine tool movement, adjust the Z1-axis lifting device 7 and the Z2-axis lifting device 9 so that the center height of the digital flat panel detector 2 is consistent with the center height of the selected X-ray source, and adjust the two parts to the bottom of the workpiece detection area. Control the X-axis moving device so that the center of the part detection platform is located on the line connecting the centers of the Z1-axis lifting device 7 and the Z2-axis lifting device 9. Control the Y-axis moving device to adjust the workpiece to the optimal focal length position of the detection system in front and behind.

[0025] (3) CT scanning starts: the computer is controlled to drive the digital flat panel to start, and then the required radiation source is turned on to emit the radiation beam, and the C-axis rotating device 8 is started to allow the workpiece to start rotating along the axis at the complete imaging speed until the connecting rod workpiece rotates one circle. When the workpiece is large, the Z1-axis lifting device 7 and the Z2-axis lifting device 9 of the machine tool can be driven to synchronously move one detection scanning effective area to the next scanning area, and the above operations are repeated until the entire connecting rod workpiece is scanned and inspected.

[0026] (4) Image reconstruction stage: The operator controls the computer's CT scanning software to reconstruct the two-dimensional projection data collected by the detector after transillumination into three dimensions through software algorithms to construct a visual three-dimensional data model or tomographic slice image.

[0027] (5) Defect identification: Through the visualization of three-dimensional data models or tomographic slice images constructed by computer software, a series of methods such as grayscale adjustment and contrast adjustment are used to perform image analysis to identify the defect position and size of the inspected connecting rod parts, locate the defects, and store the pattern inspection results and generate a report after the identification is completed.

[0028] (6) Ending stage: After the identification is completed, turn off the X-ray detector system, remove the connecting rod detection fixture, adjust the machine tool to the zero position, and complete the detection.

[0029] The beneficial effects of the present invention are:

[0030] 1. The system of the present invention uses a dual-ray detection system, which can adapt to different connecting rod sizes or select appropriate ray sources for irradiation detection under different conditions.

[0031] 2. The present invention can achieve the accuracy of connecting rod detection. In the connecting rod detection tooling structure, the support rods are distributed on the outside of the connecting rod parts while meeting the requirements of tension support, thereby minimizing the obstruction of the connecting rod parts by the support rods during the non-destructive testing irradiation process.

[0032] 3. The present invention can realize all-round and all-angle detection of connecting rod parts through the movement of the rotating motion axis of the machine tool, which can improve the integrity of the scanned image, improve the image reconstruction efficiency, and increase the accuracy of defect identification. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the industrial CT detection system for connecting rods of marine engines of the present invention;

[0034] Figure 2 It is a schematic diagram of the working part structure of the machine tool of the present invention;

[0035] Figure 3 It is a structural diagram of the connecting rod detection tooling of the present invention;

[0036] Among them, 1-detection machine tool body; 2-digital flat panel detector; 3-connecting rod detection fixture; 4-parts detection platform; 5-accelerator radiation source; 6-X-ray machine radiation source; 7-Z1 axis lifting device; 8-C axis rotation device; 9-Z2 axis lifting device; 10-detector fixing frame; 11-Y axis moving device; 12-X axis moving device; 13-radiation source fixing frame; 14-small end chassis; 15-small end holder; 16-connecting rod parts; 17-positive thread support rod; 18-hexagonal double-head screw; 19-negative thread support rod; 20-big end holder; 21-big end chassis; 22-chassis locking assembly. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention will be described clearly and completely below so that those skilled in the art can better understand the advantages and features of the present invention and thus more clearly define the scope of protection of the present invention. The embodiments described in the present invention are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without making any creative work shall fall within the scope of protection of the present invention.

[0038] like Figure 1 As shown, the marine engine connecting rod industrial CT detection system of this embodiment is composed of the following parts:

[0039] Detection machine tool body 1: includes a multi-axis motion device (Z1-axis lifting device 7, Z2-axis lifting device 9, X-axis moving device 12, Y-axis moving device 11, C-axis rotation device 8), used to adjust the relative position of the workpiece and the detector, as well as a detector fixing frame 10, a radiation source fixing frame 13 and a part detection platform 4.

[0040] The X-ray scanning device, mounted on the X-ray source mounting bracket 13, includes an X-ray source 6 (in this embodiment, an MXR-451HP / 11 with a power of 1500W and a maximum voltage of 450kV), suitable for high-definition imaging of small or thin-walled connecting rods. An accelerator source 5 (in this embodiment, a 2-6 MeV linear accelerator) is suitable for deep penetration testing of large or thick-walled connecting rods.

[0041] The digital flat panel detector 2 (model XRD1611 is used in this embodiment) is fixed on the detector fixing frame 10 and is used to receive the ray signal after penetrating the workpiece and generate two-dimensional projection data.

[0042] The connecting rod inspection fixture 3 is fixed on the parts inspection platform 4 and is used to fix connecting rods of different sizes to ensure that there is no vibration or displacement during the inspection process.

[0043] Assembly of connecting rod inspection tool 3:

[0044] Secure the small-end chassis (14) and the small-end holder (15) with hexagon socket countersunk screws, and secure the large-end holder (20) and the large-end chassis (21) with hexagon socket countersunk screws. Install four positive-thread support rods (17) on the small-end chassis (14), and four negative-thread support rods (19) on the large-end chassis (21). Connect the positive-thread support rods (17) and negative-thread support rods (19) respectively with four hexagonal stud screws (18). Rotating the hexagonal stud screws (18) adjusts the clamping force to ensure that the connecting rod (16) is firmly fixed. Use a set screw to lock the side of the connecting rod to prevent loosening during the inspection process.

[0045] The assembled tooling is fixed to the center of the part detection platform (4) through the chassis locking assembly (22) to ensure that there is no deviation when the workpiece rotates.

[0046] CT scan detection process:

[0047] (1) Selection of radiation source:

[0048] Select the X-ray source based on the connecting rod size and thickness:

[0049] Small / thin-wall connecting rod: Using X-ray source (6), the focus can be adjusted to 0.4mm to improve the image clarity.

[0050] Large / thick-walled connecting rods: Use accelerator radiation source (5) to ensure radiation penetration capability.

[0051] (2) System calibration:

[0052] The Z1 axis lifting device (7) and the Z2 axis lifting device (9) are adjusted to align the center of the digital flat panel detector (2) with the center of the ray source.

[0053] The position of the workpiece is adjusted by the X-axis moving device (12) and the Y-axis moving device (11) so as to be located at an optimal focal length.

[0054] (3) CT scan:

[0055] Start the digital flat panel detector (2) and the selected radiation source.

[0056] The C-axis rotating device (8) is controlled to rotate the workpiece 360 degrees at a constant speed to complete single-layer scanning.

[0057] For large connecting rods, the Z1 and Z2 axes can be moved synchronously to perform layered scanning to ensure that the entire inspection area is covered.

[0058] (4) Image reconstruction and analysis:

[0059] The two-dimensional projection data collected by the detector is transmitted to the computer, and the CT reconstruction algorithm is used to generate a three-dimensional model or tomographic slice image.

[0060] Identify internal defects (cracks, pores, inclusions, etc.) through image enhancement techniques (such as grayscale adjustment and contrast optimization).

[0061] Record defect location and size and generate inspection report.

[0062] (5) End of test:

[0063] Turn off the X-ray source and detector, remove the connecting rod detection fixture, and reset the machine tool to its initial position.

[0064] This system allows for the selection of different X-ray sources for inspection of workpieces of varying sizes. For smaller or thinner parts, the MXR-451HP / 11 X-ray source 6 can be selected, featuring a maximum power of 1500W and a high voltage of up to 450kV. This X-ray source also allows for a minimum focal spot of 0.4mm, enabling high-definition imaging. For larger or thicker parts where the X-ray source cannot penetrate, the accelerator source 5, a 2-6MeV linear accelerator, can be selected by adjusting the Z2-axis lift mechanism 9. Both beams can be scanned and imaged using the XRD1611 flat-panel detector. During the inspection process, a radiation source is used to emit radiation to penetrate the connecting rod parts to be inspected. The penetrated radiation is received by the detector. According to the different attenuation coefficients of each volume element in each transmission direction and the different transmission energy received by the detector, a certain image reconstruction algorithm can be used to obtain a thin layer of tomographic scanning image without image overlap of the inspected workpiece. By repeating the above process, another new tomographic image can be obtained. When there are enough two-dimensional tomographic images, a three-dimensional image can be reconstructed, so that the location and size of the defect can be more intuitively discovered.

[0065] This example uses a dual system of X-ray sources (450kV) and accelerator sources (2-6MeV) to optimize inspection for small / thin-walled and large / thick-walled connecting rods, respectively. Computer-automated source selection ensures penetration and imaging clarity for workpieces of varying sizes.

[0066] A double-ended hexagonal screw (18) with positive and negative teeth is used to connect the support rods (17, 19). By rotating the screw, bidirectional synchronous clamping is achieved to ensure that the connecting rod is firmly fixed. The tooling support rods are distributed on the outside of the connecting rod to reduce obstruction to CT scanning and improve imaging integrity. The lateral set screw design prevents the workpiece from moving during the inspection process. Combined with the C-axis rotation device (8) and the Z1 / Z2 axis lifting device (7, 9), 360° rotation + layered scanning of the workpiece is achieved to ensure full coverage inspection. Multi-axis motion is controlled by a computer, and the focus and scanning area are automatically adjusted to reduce manual intervention.

Claims

1. An industrial CT inspection system for connecting rods of marine engines, characterized in that: include: A multi-axis motion detection machine tool (1) includes a Z1-axis lifting device (7), a Z2-axis lifting device (9), an X-axis moving device (12), a Y-axis moving device (11) and a C-axis rotating device (8), wherein each motion axis is controlled by a computer numerical control system; A dual-mode radiation source device comprises: an X-ray machine radiation source (6) with a maximum power of 1500W, a maximum voltage of 450kV, and a minimum focal spot size of 0.4mm; and an accelerator radiation source (5) with an energy range of 2-6MeV; A digital flat panel detector (2) is used to receive the ray signal after penetrating the workpiece and generate two-dimensional projection data; An adjustable connecting rod clamp device (3) for fixing connecting rods of different sizes to ensure no vibration or displacement during the test; A ray source fixing frame, a detector fixing frame and a parts detection platform fixed on the multi-axis motion detection machine tool (1) are used to respectively place the dual-mode ray source device, the digital flat panel detector (2) and the adjustable connecting rod clamp device (3).

2. The marine engine connecting rod industrial CT detection system according to claim 1, characterized in that: The adjustable connecting rod clamp device (3) comprises: A small-end fixing unit and a large-end fixing unit are symmetrically arranged; A bidirectional synchronous clamping mechanism is composed of four orthogonal support rods (17), four anti-tooth support rods (19) and four hexagonal double-headed screws (18), wherein the hexagonal double-headed screws (18) connect the orthogonal support rods (17) and the anti-tooth support rods (19); The lateral anti-displacement mechanism includes a set screw provided on the small end clamping seat (15) and the large end clamping seat (20); The small-end fixing unit comprises a small-end chassis (14) and a small-end clamping seat (15), and the large-end fixing unit comprises a large-end chassis (21) and a large-end clamping seat (20). The small-end chassis (14) and the small-end clamping seat (15) are fixed by hexagon socket countersunk screws, and the large-end clamping seat (20) and the large-end chassis (21) are fixed by hexagon socket countersunk screws. Four orthogonal support rods (17) are installed on the small-end chassis (14), and four anti-thread support rods (19) are installed on the large-end chassis (21).

3. The marine engine connecting rod industrial CT detection system according to claim 1, characterized in that: The threads at both ends of the hexagonal double-headed screw (18) are rotated in opposite directions and cooperate with the corresponding positive thread support rod (17) and negative thread support rod (19). A single rotation can synchronously adjust the clamping force at both ends.

4. An industrial CT detection method for connecting rods of marine engines based on the system according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Workpiece clamping: Fix the connecting rod (16) to the detection fixture (3), adjust the clamping force by the hexagonal stud screw (18), and lock the side with a set screw; S2. Radiation source selection: When the maximum wall thickness of the connecting rod is ≤100 mm, select the X-ray source (6); When the maximum wall thickness of the connecting rod is greater than 100 mm, select the accelerator radiation source (5); S3. Calibration: Adjusting the Z1 lifting device axis (7) and the Z2 lifting device axis (9) so that the radiation source, the center of the workpiece and the center of the detector are coplanar; S4. CT scan: Controlling the C-axis rotating device (8) to rotate the workpiece 360 degrees and synchronously collecting two-dimensional projection data; S5. Image processing: The FDK algorithm is used for 3D reconstruction and adaptive threshold segmentation is applied to identify defect areas; S6. Generate report: Record defect location and size and output test results.

5. The detection method according to claim 4, wherein: In step S4, for connecting rods with a length exceeding 500 mm, a layered scanning mode is adopted, and the overlap rate between layers is not less than 10%.

6. A special fixture for industrial CT inspection of marine engine connecting rods, characterized in that: include: Base assembly: small end chassis (14) and large end chassis (21), with a positioning groove at the bottom thereof matching with the detection platform (4); Clamping assembly: a small end clamping seat (15) and a large end clamping seat (20), the inner surfaces of which are provided with a contoured curved surface matching the shape of the connecting rod end; Force adjustment assembly: four groups of symmetrically distributed support rod mechanisms, each group includes: - an orthodontic support rod (17), fixed to the small end chassis (14); -Anti-thread support rod (19), fixed to the large end chassis (21); - a hexagonal double-head screw (18), the two ends of which are respectively threadedly connected to the positive thread and negative thread support rods; an anti-loosening component: a set screw arranged in the radial direction of each card seat, and a nylon anti-slip pad is provided at the end of the screw.

7. The special fixture according to claim 6, characterized in that: The curvature radius tolerance of the contoured surface is controlled within ±0.05 mm, and the surface roughness Ra is ≤ 1.6 μm.

8. A computer controlled device, characterized in that include: Motion control module, used to coordinate the motion of each axis; A ray source management module, used for automatically selecting and controlling ray source parameters; Image processing module for 3D reconstruction and defect recognition; The control device is configured to perform the method steps of claims 4-5.

Images