Numerical control machine tool spindle surface defect laser detection device and method

Abstract

The invention belongs to the technical field of numerical control machine tool detection, and particularly relates to a numerical control machine tool spindle surface defect laser detection device and method. According to the numerical control machine tool spindle surface defect laser detection device, after the laser beams emitted by the laser device pass through the beam expander, parallel laser beams with large diameters are obtained, the laser beams are incident to the surface of the numerical control machine tool electric spindle through the first total reflection reflector, and then the propagation direction is changed through the second total reflection reflector; then a camera is adopted to shoot a numerical control machine tool motorized spindle surface picture imaged by the microscope, and a computer is adopted to record the surface state of the numerical control machine tool motorized spindle in a normal working state, so that the health state monitoring of the surface of the numerical control machine tool motorized spindle is realized. The laser detection method is adopted to carry out rapid, real-time, dynamic and high-precision monitoring on the health state of the surface of the electric spindle of the numerical control machine tool, and the method has the advantages of non-contact, visualization and high spatial resolution.

Description

Technical Field

[0001] This application belongs to the technical field of numerical control machine tool detection, and particularly relates to a laser detection device and method for surface defects of a spindle of a numerical control machine tool. Background Art

[0002] In modern high-end military and civilian equipment, components generally have very complex geometric structures and high-precision detection requirements. At the same time, high-performance materials such as titanium alloys, superalloys, stainless steels, high-strength aluminum alloys, and composite materials are widely used to ensure the special requirements of products for their service performance, environment, strength, and weight. High-end numerical control machine tools such as five-axis high-speed machining centers are the core equipment for processing such complex and precision-structured parts. Their health status directly affects the machining quality and efficiency of parts. Once a failure occurs, it will cause long-term shutdowns and seriously affect and restrict the production progress of products. The failures of machining centers can be divided into three categories: numerical control system failures, electrical control system failures, and mechanical system failures. Among them, numerical control system failures and electrical control system failures can be diagnosed through the built-in diagnostic functions of the numerical control system. For mechanical system failures with the highest failure rate, there is currently no effective method for monitoring and diagnosis.

[0003] The electric spindle is the core functional component of a five-axis high-speed machining center, and its failures are the most common and frequent in the mechanical system. At present, the main daily maintenance strategies for electric spindles are after-sales maintenance and regular maintenance. There are often problems such as over-maintenance or under-maintenance, poor pertinence, low efficiency, and high cost in operation and maintenance, making it difficult to ensure the long-term reliable operation of five-axis high-speed machining centers.

[0004] Therefore, there is an urgent need for a technical solution to overcome or alleviate at least one of the above defects of the existing technology. Summary of the Invention

[0005] The purpose of this application is to provide a laser detection device and method for surface defects of a spindle of a numerical control machine tool to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is as follows: The first aspect of this application provides a laser detection device for surface defects of a spindle of a numerical control machine tool, including: A moving and positioning module, including a fixed support frame, rolling pulleys, and a pulley fixing rod. There are two rolling pulleys, namely a first rolling pulley and a second rolling pulley. The two rolling pulleys are respectively installed on the fixed support frame in a rolling manner, and the two rolling pulleys are connected by the pulley fixing rod; A laser emission module, including a laser and a beam expander. The laser and the beam expander are coaxially installed below the first rolling pulley, and the beam expander is used to process the laser beam emitted by the laser; A laser imaging module, comprising a microscope and a camera, wherein the microscope and the camera are coaxially mounted below the second rolling pulley, and the camera is used to capture pictures of the surface of the electric spindle of a numerically controlled machine tool after imaging by the microscope; A laser reflection module, comprising two total reflection mirrors, namely a first total reflection mirror and a second total reflection mirror. The first total reflection mirror is used to reflect the laser beam from the beam expander to the surface of the electric spindle of the numerically controlled machine tool, and the second total reflection mirror is used to reflect the laser beam from the surface of the electric spindle of the numerically controlled machine tool to the microscope; A data processing module, comprising a computer, which is used to monitor the health status of the surface of the electric spindle of the numerically controlled machine tool according to the pictures of the surface of the electric spindle of the numerically controlled machine tool.

[0007] In at least one embodiment of the present application, the laser emits a 532nm laser beam.

[0008] In at least one embodiment of the present application, the camera is a millisecond-level pixel camera.

[0009] In at least one embodiment of the present application, the laser beam incident from the beam expander to the first total reflection mirror is parallel to the laser beam reflected from the second total reflection mirror to the microscope.

[0010] In at least one embodiment of the present application, the movement and positioning module further comprises two positioning brackets, a first positioning bracket and a second positioning bracket. The overall positioning of the first rolling pulley, the laser, the beam expander and the first total reflection mirror is realized through the first positioning bracket, and the overall positioning of the second rolling pulley, the camera, the microscope and the second total reflection mirror is realized through the second positioning bracket.

[0011] In at least one embodiment of the present application, the rolling pulley is configured with a movement control module, and the movement control module is used to control the movement speed and displacement of the rolling pulley.

[0012] The second aspect of the present application provides a method for laser detection of surface defects of a numerically controlled machine tool spindle, based on the above-mentioned laser detection device for surface defects of a numerically controlled machine tool spindle, comprising: Obtain a test piece of the electric spindle of a numerically controlled machine tool, and prepare a reference indentation and a target indentation on the surface of the test piece of the electric spindle of the numerically controlled machine tool; Assemble the laser detection device for surface defects of the numerically controlled machine tool spindle, and obtain a reference indentation picture and a target indentation picture through the laser detection device for surface defects of the numerically controlled machine tool spindle; Taking the defect width in the reference indentation image as a reference, calculate the measurement error and relative error of the defect width in the target indentation image; According to the measurement error and the relative error, verify whether the laser detection device for the surface defects of the CNC machine tool spindle meets the reliability requirements. If it meets the requirements, monitor the health status of the surface of the electric spindle of the CNC machine tool through the laser detection device for the surface defects of the CNC machine tool spindle.

[0013] In at least one embodiment of the present application, the test piece of the electric spindle of the CNC machine tool is made of carbon steel, and the surface of the test piece of the electric spindle of the CNC machine tool is polished.

[0014] In at least one embodiment of the present application, the measurement error is: ; Wherein, is the measurement error, is the target indentation size, is the reference indentation size, is the defect width in the target indentation image, is the defect width in the reference indentation image.

[0015] In at least one embodiment of the present application, the relative error is: ; Wherein, is the relative error.

[0016] The invention has at least the following beneficial technical effects: The laser detection device for the surface defects of the CNC machine tool spindle in the present application monitors the surface defects of the electric spindle of the CNC machine tool by means of laser beam expansion and microscopic optical imaging, realizing the visual diagnosis of the surface defects of the electric spindle of the CNC machine tool. Compared with existing technologies such as vibration analysis method and ultrasonic detection method, the non-contact detection method can ensure the normal operation of the equipment, avoid a large amount of complex data analysis and calculation, quickly identify surface defects, and achieve precise positioning. The imaging process does not require scanning, and can monitor the surface defect situation of the electric spindle of the CNC machine tool under normal working conditions in real time, realizing long-term and dynamic evaluation. Description of the Drawings

[0017] Figure 1 is a schematic diagram of a laser detection device for the surface defects of the CNC machine tool spindle in an embodiment of the present application; Figure 2 is a flowchart of a laser detection method for the surface defects of the CNC machine tool spindle in an embodiment of the present application.

[0018] Wherein: 1 - Fixed support frame; 2 - Rolling pulley; 3 - Pulley fixing rod; 4 - Laser; 5 - Beam expander; 6 - Total reflection reflector; 7 - CNC machine tool electric spindle; 8 - Microscope; 9 - Camera; 10 - Computer. Detailed implementation mode

[0019] To make the purpose, technical solution and advantages of the implementation of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below in conjunction with the accompanying drawings in the embodiments of this application.

[0020] The first aspect of this application provides a laser detection device for the surface defects of the spindle of a CNC machine tool, including: a movement and positioning module, a laser emission module, a laser imaging module, a laser reflection module, and a data processing module.

[0021] As Figure 1 shown, the movement and positioning module includes a fixed support frame 1, rolling pulleys 2, and a pulley fixing rod 3. There are two rolling pulleys 2, namely the first rolling pulley and the second rolling pulley. The two rolling pulleys 2 are respectively installed on the fixed support frame 1 in a rolling manner, and the two rolling pulleys 2 are connected by the pulley fixing rod 3. The rolling pulley 2 can move along the fixed support frame 1, driving the overall movement of the laser detection device for the surface defects of the spindle of the CNC machine tool. Through the pulley fixing rod 3, the relative positions of the two rolling pulleys 2 are fixed during movement, so as to ensure that the laser emission module and the laser imaging module can move simultaneously without changing the reflection direction of the laser beam during the movement process.

[0022] The laser emission module includes a laser 4 and a beam expander 5. The laser 4 and the beam expander 5 are coaxially installed below the first rolling pulley. The beam expander 5 is used to process the laser beam emitted by the laser 4. In this embodiment, the laser 4 can emit a 532nm laser beam. After being processed by the beam expander 5, the diameter of the laser beam increases and the divergence angle decreases, obtaining a parallel laser beam with a larger diameter.

[0023] The laser imaging module includes a microscope 8 and a camera 9. The microscope 8 and the camera 9 are coaxially installed below the second rolling pulley. After the laser beam irradiates the surface of the CNC machine tool electric spindle 7, its reflected and / or scattered light can be imaged through the microscope 8. The camera 9 is used to take pictures of the surface of the CNC machine tool electric spindle 7 after imaging through the microscope 8. In this embodiment, the camera 9 uses a millisecond-level pixel camera. By taking pictures of the surface of the CNC machine tool electric spindle 7 with the camera 9, the surface state of the CNC machine tool electric spindle 7 under normal working conditions is recorded.

[0024] The laser reflection module includes two total reflection mirrors 6, namely the first total reflection mirror and the second total reflection mirror respectively. The total reflection mirror 6 can change the propagation direction of the laser beam. The first total reflection mirror is used to reflect the laser beam from the beam expander 5 to the surface of the CNC machine tool electric spindle 7, and the second total reflection mirror is used to reflect the laser beam from the surface of the CNC machine tool electric spindle 7 to the microscope 8. Among them, the laser beam incident on the first total reflection mirror from the beam expander 5 is parallel to the laser beam reflected by the second total reflection mirror to the microscope 8.

[0025] The data processing module includes a computer 10. The computer 10 can receive the pictures of the surface of the CNC machine tool electric spindle 7 taken by the camera 9, and dynamically and real-time monitor and evaluate the health status of the surface of the CNC machine tool electric spindle 7 by analyzing the scattering situation of the laser beam on the surface of the CNC machine tool electric spindle 7.

[0026] For the laser detection device for surface defects of the CNC machine tool spindle in this application, the movement and positioning module further includes two positioning brackets. Preferably, the overall positioning of the first rolling pulley, the laser 4, the beam expander 5 and the first total reflection mirror is realized through the first positioning bracket, and the overall positioning of the second rolling pulley, the camera 9, the microscope 8 and the second total reflection mirror is realized through the second positioning bracket. When the rolling pulley 2 moves through the two positioning brackets, it drives the whole laser detection device for surface defects of the CNC machine tool spindle to move, so as to realize the monitoring of different positions on the surface of the CNC machine tool electric spindle 7. In the preferred embodiment of this application, the rolling pulley 2 is configured with a movement control module, and the movement speed and displacement of the rolling pulley 2 are automatically controlled through the movement control module to realize the movement and positioning functions.

[0027] For the laser detection device for surface defects of the CNC machine tool spindle in this application, after the laser beam emitted by the laser 4 passes through the beam expander 5, a parallel laser beam with a larger diameter is obtained. The laser beam is incident on the surface of the CNC machine tool electric spindle 7 through the first total reflection mirror, and then the propagation direction is changed through the second total reflection mirror to be parallel to the laser beam emission direction. Then, the camera 9 is used to take pictures of the surface of the CNC machine tool electric spindle 7 imaged by the microscope 8, and the computer 10 records the surface state of the CNC machine tool electric spindle 7 under the normal working state, so as to realize the health status monitoring of the surface of the CNC machine tool electric spindle 7.

[0028] For the laser detection device for surface defects of the CNC machine tool spindle in this application, the imaging principle is that when the laser beam irradiates the rough surface generated by the defect, scattering occurs, and the optical path difference existing in the scattered light makes them interfere with each other to form a granular pattern of light and dark, so as to realize the real-time monitoring of the surface defects of the CNC machine tool electric spindle 7.

[0029] The second aspect of this application provides a laser detection method for surface defects of a CNC machine tool spindle, based on the above-mentioned laser detection device for surface defects of a CNC machine tool spindle, asFigure 2 As shown, the method includes: Obtain a test piece of the electric spindle of a numerically controlled machine tool, and prepare a reference indentation and a target indentation on the surface of the test piece of the electric spindle of the numerically controlled machine tool; Assemble a laser detection device for surface defects of the spindle of a numerically controlled machine tool, and obtain a reference indentation picture and a target indentation picture through the laser detection device for surface defects of the spindle of the numerically controlled machine tool; Taking the defect width in the reference indentation picture as a reference, calculate the measurement error and relative error of the defect width in the target indentation picture; Verify whether the laser detection device for surface defects of the spindle of the numerically controlled machine tool meets the reliability requirements according to the measurement error and relative error. If it meets the requirements, monitor the health status of the surface of the electric spindle 7 of the numerically controlled machine tool through the laser detection device for surface defects of the spindle of the numerically controlled machine tool.

[0030] In a preferred embodiment of the present application, the test piece of the electric spindle of the numerically controlled machine tool is made of No. 45 high-quality carbon steel, and the surface of the test piece of the electric spindle of the numerically controlled machine tool is polished to make the surface smooth.

[0031] In a preferred embodiment of the present application, the measurement error is: ; Wherein, is the measurement error, is the target indentation size, is the reference indentation size, is the defect width in the target indentation picture, is the defect width in the reference indentation picture.

[0032] In this embodiment, the relative error is: ; Wherein, is the relative error.

[0033] In an embodiment of the present application, four test pieces of the electric spindle of the numerically controlled machine tool are prepared, namely the first test piece, the second test piece, the third test piece and the fourth test piece.

[0034] By preparing a reference indentation and a target indentation on each test piece of the electric spindle of the numerically controlled machine tool, simulate the surface defects under the normal working condition of the electric spindle 7 of the numerically controlled machine tool. Among them, a reference indentation with a width of 0.5 mm and a target indentation with a width of 0.1 mm are prepared on the surface of the first test piece; a reference indentation with a width of 0.5 mm and a target indentation with a width of 0.2 mm are prepared on the surface of the second test piece; a reference indentation with a width of 0.5 mm and a target indentation with a width of 0.3 mm are prepared on the surface of the third test piece; a reference indentation with a width of 0.5 mm and a target indentation with a width of 0.4 mm are prepared on the surface of the fourth test piece.

[0035] After assembling the laser detection device for the surface defects of the spindle of the numerically controlled machine tool, the incident laser beam is moved to the dent on the surface of the test piece of the motorized spindle of the numerically controlled machine tool by moving the rolling pulley 2, and the reference dent pictures and target dent pictures of each test piece of the motorized spindle of the numerically controlled machine tool are collected respectively.

[0036] Taking the defect width in the reference dent picture as a reference, calculate the measurement error and relative error of the defect width in the target dent picture, as shown in Table 1; Table 1

[0037] Determine the measurement error threshold and relative error threshold, compare the measurement error with the measurement error threshold, compare the relative error with the relative error threshold, and verify whether the laser detection device for the surface defects of the spindle of the numerically controlled machine tool meets the reliability requirements.

[0038] In this embodiment, the measurement error threshold is set to ±0.050, and the relative error threshold is set to 15%. According to Table 1, the measurement error is maintained between -0.010 and 0.020, and the relative error does not exceed 10%, both of which are lower than the corresponding error thresholds, verifying that the laser detection device for the surface defects of the spindle of the numerically controlled machine tool meets the reliability requirements.

[0039] The laser detection device and method for the surface defects of the spindle of the numerically controlled machine tool of the present application have the following beneficial effects: (1) The all-round health monitoring of the object to be measured is realized through the moving and positioning module. The traditional detection method for the surface defects of the motorized spindle is to attach the sensor to the object to be measured in the form of magnetic adsorption or bonding, which has the disadvantages of being prone to looseness and limited detection range. The present application uses the moving control module to automatically control the rolling pulley 2. On the one hand, it can realize the full-range and dead-angle-free health monitoring of the motorized spindle 7 of the numerically controlled machine tool. On the other hand, through the control of the moving speed and displacement, the accurate positioning of the surface defects of the motorized spindle 7 of the numerically controlled machine tool is realized, which plays an important role in the early rapid diagnosis, maintenance or replacement, and life prediction of the faults of the motorized spindle 7 of the numerically controlled machine tool.

[0040] (2) Using a millisecond-level pixel camera, the whole process of the motorized spindle 7 of the numerically controlled machine tool from factory, service, maintenance to scrapping is regularly detected, a surface health condition database of the motorized spindle 7 of the numerically controlled machine tool throughout its life cycle is established, the threshold value under normal use conditions of the motorized spindle 7 of the numerically controlled machine tool is deeply analyzed, and then the quality of the maintenance cycle and repair cycle of the motorized spindle 7 of the numerically controlled machine tool is evaluated, which has important practical significance for extending the service life of the equipment.

[0041] The laser detection device and method for surface defects of the spindle of a numerically controlled machine tool in this application use the laser detection method to quickly, real-time, dynamically, and highly accurately monitor the health status of the surface of the motor spindle of a numerically controlled machine tool, and have the advantages of non-contact, visualization, and high spatial resolution.

[0042] As described above, it is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the technical field within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the said claims.

Claims

1. A laser detection device for surface defects of a CNC machine tool spindle, characterized in that: include: A moving and positioning module comprises a fixed support frame (1), a rolling pulley (2) and a pulley fixing rod (3), wherein the rolling pulley (2) comprises two, namely a first rolling pulley and a second rolling pulley, the two rolling pulleys (2) are respectively rollingly mounted on the fixed support frame (1), and the two rolling pulleys (2) are connected via the pulley fixing rod (3); A laser emission module, comprising a laser (4) and a beam expander (5), wherein the laser (4) and the beam expander (5) are coaxially mounted below the first rolling pulley, and the beam expander (5) is used to process a laser beam emitted by the laser (4); A laser imaging module, comprising a microscope (8) and a camera (9), wherein the microscope (8) and the camera (9) are coaxially mounted below the second rolling pulley, and the camera (9) is used to take a picture of the surface of the CNC machine tool electric spindle (7) imaged by the microscope (8); A laser reflection module, comprising two total reflection mirrors (6), namely a first total reflection mirror and a second total reflection mirror, wherein the first total reflection mirror is used to reflect the laser beam from the beam expander (5) to the surface of the CNC machine tool electric spindle (7), and the second total reflection mirror is used to reflect the laser beam from the surface of the CNC machine tool electric spindle (7) to the microscope (8); The data processing module comprises a computer (10), wherein the computer (10) is used to monitor the health status of the surface of the CNC machine tool electric spindle (7) based on the surface image of the CNC machine tool electric spindle (7).

2. The CNC machine tool spindle surface defect laser detection device according to claim 1, characterized in that: The laser (4) emits a 532 nm laser beam.

3. The CNC machine tool spindle surface defect laser detection device according to claim 1, characterized in that: The camera (9) is a millisecond-level pixel camera.

4. The CNC machine tool spindle surface defect laser detection device according to claim 1, characterized in that: The direction of the laser beam incident on the first total reflection mirror by the beam expander (5) is parallel to the direction of the laser beam reflected by the second total reflection mirror to the microscope (8).

5. The CNC machine tool spindle surface defect laser detection device according to claim 1, characterized in that: The moving and positioning module also includes two positioning brackets, a first positioning bracket and a second positioning bracket, wherein the first positioning bracket is used to realize the overall positioning of the first rolling pulley, the laser (4), the beam expander (5) and the first total reflection reflector, and the second positioning bracket is used to realize the overall positioning of the second rolling pulley, the camera (9), the microscope (8) and the second total reflection reflector.

6. The CNC machine tool spindle surface defect laser detection device according to claim 5, characterized in that: The rolling pulley (2) is provided with a movement control module, and the movement control module is used to control the movement speed and displacement of the rolling pulley (2).

7. A method for detecting surface defects of a CNC machine tool spindle by laser, based on the CNC machine tool spindle surface defect laser detection device according to any one of claims 1 to 6, characterized in that: include: Obtain a CNC machine tool electric spindle test piece, and prepare a reference indentation and a target indentation on the surface of the CNC machine tool electric spindle test piece; Assembling the CNC machine tool spindle surface defect laser detection device, and obtaining a reference dent image and a target dent image through the CNC machine tool spindle surface defect laser detection device; Taking the defect width in the reference dent image as a reference, calculating the measurement error and relative error of the defect width in the target dent image; Verify whether the CNC machine tool spindle surface defect laser detection device meets the reliability requirement based on the measurement error and the relative error; if so, monitor the health status of the surface of the CNC machine tool electric spindle (7) through the CNC machine tool spindle surface defect laser detection device.

8. The laser detection method for surface defects of a CNC machine tool spindle according to claim 7, characterized in that: The CNC machine tool electric spindle test piece is made of carbon steel, and the surface of the CNC machine tool electric spindle test piece is polished.

9. The laser detection method for surface defects of a CNC machine tool spindle according to claim 8, characterized in that: The measurement error is: ； in, is the measurement error, is the target dent size, For reference dent size, is the defect width in the target dent image, is the defect width in the reference dent image.

10. The laser detection method for surface defects of a CNC machine tool spindle according to claim 9, characterized in that: The relative error is: ； in, is the relative error.

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