Workpiece surface coating bonding strength scratch detection device and method

Abstract

According to the workpiece surface coating bonding strength scratch detection device and method provided by the invention, the workpiece surface characteristics can be identified, so that the movement path of the scriber is planned, the scriber can change the movement direction along with the change of the surface shape of the workpiece, and the detection of the workpiece with the curved surface characteristics can be realized. The scratch detection device comprises a three-axis moving mechanism, a scriber unit, an observation unit and a workpiece clamp, the scriber unit is mounted on the three-axis moving mechanism, can move on the coating surface of the workpiece to be tested along a planned scriber moving path, scribes on the coating surface of the workpiece to be tested by using a scriber, and applies a test load to the workpiece to be tested; the observation unit is installed on the three-axis moving mechanism, can observe the surface shape of a workpiece to be measured and is used for planning the moving path of the scriber. Meanwhile, the observation unit can also be used for observing the appearance of a scratch scratched by the scriber unit on the surface of the coating of the workpiece to be detected; the workpiece clamp is used for clamping a to-be-tested workpiece.

Description

Technical Field

[0001] The present invention relates to a scratch detection device and method, in particular to a workpiece surface coating bonding strength scratch detection device and method, belonging to the technical field of surface coating bonding strength detection. Background Art

[0002] The bonding strength between the coating and the substrate is one of the key indicators for evaluating the quality of the coating. The scratch method is an important method for testing the bonding strength of the coating. The basic process is to use a diamond tip to scratch the coating surface at a certain speed while continuously increasing the load applied to the tip until the coating peels off. The critical load Lc at the time of peeling is defined as the interface bonding force (i.e., the critical bonding force of the coating). The scratch method has the advantages of simple testing, less time consumption, and no special sample treatment required. It is one of the most widely used bonding strength test methods. Figure 1 This is an illustration of the scratch test method.

[0003] Conventional scratch testers are mainly used to test experimental samples with flat features, so they are often used in laboratories. It is difficult to test workpieces with curved surface features, which greatly limits the wide application of the instrument, especially in the production site of enterprises. At present, there are few automatic detection devices on the market for the bonding strength of surface coatings on workpieces with curved surface features.

[0004] The existing scratch tester's stylus cannot change its movement direction as the workpiece surface shape changes. Once it encounters a non-planar workpiece, it will be difficult to detect, such as a cylindrical surface, a spherical surface, a concave surface, etc. Summary of the invention

[0005] In view of this, the present invention provides a workpiece surface coating bonding strength scratch detection device, which can identify the surface features of the workpiece and then plan the moving path of the scratching needle, so that the scratching needle can change the movement direction as the shape of the workpiece surface changes, thereby realizing the detection of workpieces with curved surface features.

[0006] The technical solution of the present invention is: a workpiece surface coating bonding strength scratch detection device, comprising: a three-axis moving mechanism, a stylus unit, an observation unit and a workpiece fixture;

[0007] The stylus unit is mounted on a three-axis moving mechanism and can move along a planned stylus moving path on the coating surface of the workpiece to be tested. Based on the scratch method, the stylus is used to scratch the coating surface of the workpiece to be tested and a test load is applied to the workpiece to be tested.

[0008] The observation unit is installed on the three-axis moving mechanism, and can observe the surface shape of the workpiece to be measured, so as to plan the moving path of the stylus; at the same time, the observation unit can also observe the morphology of scratches on the coating surface of the workpiece to be measured by the stylus unit;

[0009] The workpiece fixture is used for clamping the workpiece to be measured.

[0010] As a preferred embodiment of the present invention: the vertical direction in the three-axis moving mechanism is defined as the Z direction;

[0011] The scribing unit comprises: a Z-axis rotation motor, a scribing support rod, a scribing needle and a scribing needle swing motor;

[0012] The stylus unit is mounted on the three-axis moving mechanism via a stylus unit mounting support seat; the stylus mounting seat is supported on the stylus unit mounting support seat via a Z-axis rotating bearing; a Z-axis rotating motor is provided on the stylus unit mounting support seat, and an output shaft of the Z-axis rotating motor is connected to the stylus mounting seat for driving the stylus mounting seat to rotate around the Z direction;

[0013] The stylus mounting rod is supported on the stylus mounting seat by a bearing, and the axis of the stylus mounting rod is perpendicular to the output shaft of the Z-axis rotating motor; the stylus is connected to the stylus mounting rod through the stylus supporting rod; the stylus swinging motor is installed on the stylus mounting seat, and is used to drive the stylus mounting rod to rotate around its own axis, thereby driving the stylus to swing.

[0014] As a preferred embodiment of the present invention, the stylus unit further comprises a longitudinal force sensor for monitoring the longitudinal load applied by the stylus to the workpiece to be tested and a lateral force sensor for monitoring the friction force during the scratch test.

[0015] As a preferred embodiment of the present invention, an acoustic emission sensor is installed on the scribing needle to monitor the sound signal during the working process of the scribing needle.

[0016] As a preferred embodiment of the present invention: the observation unit comprises: an observation unit mounting seat, a lifting mechanism, a camera module, a laser scanner and a scratch observation module;

[0017] The observation unit mounting seat is connected to the three-axis moving mechanism;

[0018] The camera module is mounted on the observation unit mounting seat via a flexible rod;

[0019] The lifting mechanism is installed on the observation unit mounting base, and the lifting mechanism is connected to a turret, on which a laser scanner and a scratch observation module are installed; the laser scanner is used to perform laser scanning on the surface of the workpiece to be measured, and then construct an observation of the surface shape of the workpiece to be measured; the scratch observation module is used to observe the scratch morphology on the surface of the workpiece to be measured.

[0020] As a preferred embodiment of the present invention: the lifting mechanism comprises: a lifting rack, a gear, and a lifting rack driving motor;

[0021] On the side of the lifting rack driving motor, the gear is coaxially connected to the output shaft of the lifting rack driving motor, and the vertically arranged lifting rack is meshed with the gear;

[0022] The lower end of the lifting rack is connected to the turret.

[0023] As a preferred embodiment of the present invention: the three-axis moving mechanism comprises: a support frame, an X-axis moving unit, a Y-axis moving unit and a Z-axis moving unit;

[0024] The vertical direction is the Z direction, the width direction of the support frame is the X direction, and the length direction is the Y direction;

[0025] The support frame includes a base and four upright posts distributed on the base in a rectangular shape; the tops of two adjacent upright posts are connected by a transverse connecting piece to form a top frame;

[0026] The Y-direction moving unit is arranged on the top frame, the X-direction moving unit is installed on the Y-direction moving unit, and can move along the Y direction under the drive of the Y-direction moving unit; the Z-direction moving unit is installed on the X-direction moving unit, and can move along the X direction under the drive of the X-direction moving unit; the stylus unit is installed on the Z-direction moving unit, and can move along the Z direction under the drive of the Z-direction moving unit.

[0027] In addition, the present invention provides a method for detecting scratches on the bonding strength of a workpiece surface coating, using the above-mentioned detection device, and the steps of the detection method are:

[0028] S1. The workpiece fixture is used to clamp the workpiece to be tested;

[0029] S2. The stylus unit and the observation unit are moved to a set position by the three-axis moving mechanism;

[0030] S3. The observation unit is moved by the three-axis moving mechanism to identify the surface shape of the test area of ​​the workpiece to be measured;

[0031] S5. Planning the needle movement path according to the identified surface shape of the test area;

[0032] S6. The scratch test is performed by driving the stylus according to the stylus movement path through the three-axis moving mechanism and the stylus unit; linear loading is performed on the stylus at the same time; during the test, the observation unit photographs the test process;

[0033] S7. After the scratch test is completed, the observation unit identifies the scratch morphology of the workpiece to be tested;

[0034] S8. Determine the critical bonding strength based on the scratch morphology.

[0035] As a preferred embodiment of the present invention: in S3, in the observation unit, a laser sensor is used to perform a three-dimensional scanning on the surface of the test area of ​​the workpiece to be measured to obtain point cloud data, and then the surface shape of the workpiece to be measured is recognized.

[0036] As a preferred embodiment of the present invention: during the scratch test, the sliding needle friction force and the sound signal during the scratching needle operation are monitored in real time; the critical bonding force of the coating is determined in the priority order of scratch morphology change - sound signal mutation - friction coefficient mutation.

[0037] Beneficial effects:

[0038] (1) The detection device of the present invention can identify the surface features of the workpiece through the observation unit and plan the moving path of the stylus according to the shape features; thereby, by controlling the stylus to move along the planned moving path of the stylus on the coating surface of the workpiece to be tested, the stylus can change its movement direction as the shape of the workpiece surface changes, thereby realizing the detection of workpieces with curved surface features; the path planning is to realize the combined performance test of workpiece surfaces with different shapes.

[0039] (2) In the detection device of the present invention, the stylus unit itself has the freedom of swinging and rotating, so that the stylus can move according to the set motion trajectory through the three-axis moving mechanism in coordination with the rotation and swinging of the stylus unit itself; and by adjusting the angle and position of the stylus, the stylus can always be perpendicular to the surface of the workpiece, thereby making the scratches on the workpiece surface coating more uniform, continuous and precise.

[0040] (3) In the detection device of the present invention, a lateral force sensor is provided in the scratching needle unit to monitor the friction force during the scratch test, and an acoustic emission sensor is provided to monitor the sound signal during the operation of the scratching needle; thereby, the critical bonding force of the coating can be comprehensively judged through the scratch morphology, sound signal and friction force.

[0041] (4) In the detection device of the present invention, a high-definition camera is installed on the observation unit mounting base through a flexible rod, and the flexible rod can adjust the position of the camera module according to the position of the scratch needle; by setting a lifting mechanism, the height of the laser scanner and the scratch observation module can be adjusted, so that the high-power optical microscope and the low-power optical microscope display images make the object image in the microscope clear, and then it can be used for critical bonding force analysis.

[0042] (5) Based on the detection device, by controlling the three-axis moving mechanism, the stylus unit and the observation unit, the entire test process can be automatically completed under the control of the control unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the principle diagram of the scratch method detection;

[0044] Figure 2 and Figure 3 It is a schematic diagram of the overall structure of the detection device of the present invention;

[0045] Figure 4 It is a structural schematic diagram of a stylus unit in the detection device of the present invention;

[0046] Figure 5 It is a structural schematic diagram of an observation unit in the detection device of the present invention;

[0047] Figure 6 The working principle flow chart of the method for detecting the surface coating of a workpiece using the detection device of the present invention;

[0048] Figure 7 The specific operation steps for using the detection device of the present invention to detect the surface coating of the workpiece are shown in FIG.

[0049] Figure 8 Flow chart for workpiece contour scanning.

[0050] Among them: 100-support frame, 200-three-axis moving mechanism, 300-scratching unit, 400-observation unit, 500-workpiece fixture;

[0051] 1-Y-axis left drive motor, 2-X-axis grating ruler, 3-X-axis lead screw, 4-Y-axis right drive motor, 5-X-axis drive motor, 6-Z-axis grating ruler, 7-Z-axis lead screw, 8-control handle, 9-Z-axis drive motor, 10-Y-axis left lead screw, 11-Y-axis left grating ruler, 12-Y-axis right grating ruler, 13-Y-axis right lead screw, 14-support arm, 15-column, 16-base; 17-Z-axis rotation motor, 18-scratching support Support rod, 19-acoustic emission sensor, 20-scratching needle, 21-scratching needle unit mounting support, 22-Z-axis rotation bearing, 23-scratching needle swing motor, 24-scratching needle mounting seat, 25-lifting rack, 26-observation unit mounting seat, 27-flexible rod, 28-high-definition camera, 29-laser scanner, 30-lifting rack drive motor, 31-turret, 32-high-power optical microscope, 33-low-power optical microscope, 34-spare mounting port. DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0053] Embodiment 1:

[0054] The present embodiment provides a workpiece surface coating bonding strength scratch detection device, which is based on the scratch detection principle, has workpiece adaptive capability, can identify the shape features of the workpiece surface (the workpiece surface here includes the inner surface and the outer surface), change the movement direction according to the workpiece surface shape, and thus can realize the detection of workpieces with curved surface features.

[0055] like Figure 2 As shown, the detection device includes: a detection unit and a control unit for controlling the detection unit; wherein the detection unit includes: a three-axis moving mechanism 200, a stylus unit 300, an observation unit 400 and a workpiece fixture 500.

[0056] The stylus unit 300 is mounted on the three-axis moving mechanism 200, and can be translated in three directions perpendicular to each other in pairs under the drive of the three-axis moving mechanism 200 (i.e., the stylus unit 300 has three translational degrees of freedom through the three-axis moving mechanism 200); the stylus unit 300 itself has rotational and swinging degrees of freedom; based on the scratch method, the stylus unit 300 moves along the planned path under the drive of the three-axis moving mechanism 200 and the action of its own rotational and swinging degrees of freedom, uses the stylus to scratch the coating surface of the workpiece to be tested, and applies a test load to the workpiece to be tested; the observation unit 400 is mounted on the three-axis moving mechanism 200, and can be translated in three directions perpendicular to each other in pairs under the drive of the three-axis moving mechanism 200, and is used to observe the surface shape of the workpiece to be tested and the scratches made by the stylus unit 300; the workpiece fixture 500 is used to clamp and fix the workpiece to be tested.

[0057] The control unit is electrically connected to the three-axis moving mechanism 200, the stylus unit 300, and the observation unit 400, respectively, to realize motion control of the three, and receive the surface shape of the workpiece observed by the observation unit 400. The control unit plans the motion trajectory of the stylus unit 300 according to the surface shape of the workpiece observed by the observation unit 400, and automatically controls the loading force and loading direction (the loading direction is the normal direction of the current position of the workpiece surface, and adjusting the angle and position of the stylus can make the stylus always perpendicular to the workpiece surface); in addition, the control unit determines the critical bonding force of the coating according to the scratches observed by the observation unit 400.

[0058] Specific:

[0059] First, let the three directions perpendicular to each other be X, Y and Z respectively, as follows Figure 3 As shown, the height direction of the support frame 100 is the Z direction, the width direction is the X direction, and the length direction is the Y direction.

[0060] The three-axis moving mechanism 200 includes: a support frame 100, an X-axis moving unit, a Y-axis moving unit and a Z-axis moving unit;

[0061] The support frame 100 includes a base 16 and four columns 15 distributed in a rectangular shape on the base 16; the tops of two adjacent columns 15 are connected by a transverse connecting piece to form a top frame. The X-axis moving unit, the Y-axis moving unit and the Z-axis moving unit are installed on the top frame.

[0062] The stylus unit 300 is mounted on the Z-direction moving unit through the support arm 14, and can move in the Z direction under the drive of the Z-direction moving unit; the Z-direction moving unit is connected to the X-direction moving unit, and can move in the X direction under the drive of the X-direction moving unit; the X-direction moving unit is connected to the Y-direction moving unit, and can move in the Y direction under the drive of the Y-direction moving unit. Thus, the stylus unit 300 has translational freedom in the three directions of X, Y, and Z through the three-axis moving mechanism 200.

[0063] As an example, the X-axis moving unit, the Y-axis moving unit and the Z-axis moving unit all adopt a ball screw linear module (that is, the movement mode of the driving motor driving the lead screw); therefore, the Y-axis moving unit includes: a Y-axis left-side driving motor 1, a Y-axis left-side lead screw 10, a Y-axis left-side grating scale 11, a Y-axis right-side driving motor 4, a Y-axis right-side lead screw 13 and a Y-axis right-side grating scale 12; that is, in this example, two lead screws are arranged parallel to the Y-axis on the top frame, namely, the Y-axis left-side lead screw 10 and the Y-axis right-side lead screw 13; the Y-axis left-side lead screw 10 is connected to the Y-axis left-side driving motor 1, and the Y-axis right-side lead screw 13 is connected to the Y-axis right-side driving motor 4; at the same time, a Y-axis left-side grating scale 11 is arranged at a position on the top frame corresponding to the Y-axis left-side lead screw 10, and a Y-axis right-side grating scale 12 is arranged at a position corresponding to the Y-axis right-side lead screw 13.

[0064] The X-axis moving unit includes: an X-axis driving motor 5, an X-axis lead screw 3 and an X-axis grating ruler 2; the X-axis lead screw 3 is arranged along the X-axis, and its two ends are supported on the nut seat by bearings respectively, and the two nut seats and the Y-axis left lead screw 10 and the Y-axis right lead screw 13 form a lead screw nut pair; and one end of the X-axis lead screw 3 extends out of the nut seat on one side and is connected to the X-axis driving motor 5; an X-axis grating ruler 2 is arranged between the two nut seats. The control unit controls the Y-axis left drive motor 1 and the Y-axis right drive motor 4 to work synchronously, so that when the Y-axis left drive motor 1 drives the Y-axis left lead screw 10 to rotate, and the Y-axis right drive motor 4 drives the Y-axis right lead screw 13 to rotate, the X-axis moving unit moves along the Y-axis, and the displacement of the X-axis moving unit along the Y-axis is detected by the Y-axis left grating ruler 11 and the Y-axis right grating ruler 12.

[0065] The Z-axis moving unit includes: a Z-axis driving motor 9, a Z-axis lead screw 7 and a Z-axis grating ruler 6; the Z-axis lead screw 7 is arranged along the Z-axis, and the Z-axis lead screw 7 forms a lead screw nut pair with the X-axis lead screw 3 through a nut seat; therefore, when the X-axis driving motor 5 drives the X-axis lead screw 3 to rotate, the Z-axis moving unit moves along the X-axis; the distance moved by the Z-axis moving unit along the X-axis is monitored by the X-axis grating ruler 2. The Z-axis lead screw 7 is connected to the Z-axis driving motor 9, and a Z-axis grating ruler 6 is arranged at a position corresponding to the Z-axis lead screw 7 along the Z-axis.

[0066] One end of the support arm 14 forms a screw nut pair with the Z-axis screw 7 through a nut seat, and the other end is connected to the stylus unit 300; when the Z-axis drive motor 9 drives the Z-axis screw 7 to rotate, the support arm 14 moves along the Z direction; the distance moved by the support arm 14 along the Z direction is monitored by the Z-axis grating ruler 6.

[0067] As an example, the above-mentioned driving motors are all stepper motors, which are electrically connected to the control unit respectively. The control unit can be connected to the host computer, so that the three-axis moving mechanism 200 can be controlled by the host computer; a manipulation handle 8 can also be set on the base 16, and the three-axis moving mechanism 200 can be controlled by the manipulation handle 8.

[0068] like Figure 4 As shown, the scribing needle unit 300 includes: a Z-axis rotating motor 17, a scribing needle support rod 18, a scribing needle 20 and a scribing needle swinging motor 23; the scribing needle unit 300 is installed on the lower end surface of the support arm 14 through the scribing needle unit mounting support seat 21, that is, the scribing needle unit mounting support seat 21 is fixedly connected to the support arm 14; the scribing needle mounting seat 24 is supported on the scribing needle unit mounting support seat 21 through a Z-direction rotating bearing 22; the scribing needle unit mounting support seat 21 is provided with a Z-axis rotating motor 17 (that is, the axial direction of the output shaft of the motor is along the Z direction), and the output shaft of the Z-axis rotating motor 17 is connected to the scribing needle mounting seat 24 for driving the scribing needle mounting seat 24 to rotate around the Z direction.

[0069] The stylus mounting rod is supported on the stylus mounting seat 24 through a bearing, and the axis of the stylus mounting rod is perpendicular to the output shaft of the Z-axis rotating motor 17; the stylus 20 is connected to the stylus mounting rod through the stylus support rod 18 (the stylus 20 can be installed on the stylus support rod 18 by threaded connection or bolt fixing); the stylus swing motor 23 is installed on the stylus mounting seat 24, and is used to drive the stylus mounting rod to rotate around its own axis, thereby driving the swing of the stylus 20. Therefore, the stylus position can be adjusted and the stylus can be controlled to move according to the set motion trajectory through the three-axis moving mechanism 200 in conjunction with the Z-axis rotating motor 17 and the stylus swing motor 23.

[0070] In addition, the stylus unit 300 further includes a longitudinal force sensor and a transverse force sensor; wherein the longitudinal force sensor is used to monitor the longitudinal load applied by the stylus 20 to the workpiece (the longitudinal load can be monitored by monitoring the reaction force of the workpiece along the axial direction of the stylus support rod 18), and the transverse force sensor is used to monitor the friction force (transverse force) during the scratch test. As an example, the longitudinal force sensor and the transverse force sensor are integrated transverse and longitudinal force sensors (not shown in the figure).

[0071] As an example, an acoustic emission sensor 19 is also installed on the scribing needle 20 to monitor the sound signal during the working process of the scribing needle 20 (when the coating is peeled off, there will be a sudden change in the sound signal).

[0072] like Figure 5 As shown, the observation unit 400 includes: an observation unit mounting seat 26, a lifting mechanism, a camera module, a laser scanner 29 and a scratch observation module; wherein the camera module uses a high-definition camera 28, and the scratch observation module includes a high-power optical microscope 32 and a low-power optical microscope 33. The observation unit mounting seat 26 is connected to the side of the support arm 14; the high-definition camera 28 is installed on the observation unit mounting seat 26 through a flexible rod 27, and the flexible rod 27 can adjust the position of the high-definition camera 28 according to the position of the scratching needle 20 (fine adjustment). As an example, the flexible rod 27 is a retractable flexible rod.

[0073] The lifting mechanism includes: a lifting rack 25, a gear (arranged inside the observation unit mounting seat 26, not shown in the figure), and a lifting rack driving motor 30; the lifting rack driving motor 30 is arranged on the side of the observation unit mounting seat 26, the gear is coaxially connected to the output shaft of the lifting rack driving motor 30, and the vertically arranged lifting rack 25 is meshed with the gear, so that when the lifting rack driving motor 30 drives the gear to rotate, it can drive the lifting rack 25 to rise and fall in the vertical direction. As an example, the lifting rack 25 is vertically arranged in the center hole of the observation unit mounting seat 26 and slides with the center hole. A limit table is arranged at the upper end of the lifting rack 25 for limiting the downward travel; the lower end of the lifting rack 25 is connected to a turret 31, on which a laser scanner 29, a high-power optical microscope 32 and a low-power optical microscope 33 are installed, and a spare installation port 34 is reserved; wherein the laser scanner 29 is used to perform laser scanning on the test area of ​​the workpiece to be measured, thereby forming a three-dimensional model of the test area of ​​the workpiece to be measured.

[0074] The workpiece fixture 500 includes: a fixture base plate and a fixture. The fixture base plate is placed on the base 16, and the workpiece to be tested is placed on the fixture base plate; clamping blocks (which may be V-shaped clamping blocks or flat clamping blocks) are respectively provided on two opposite sides of the fixture base plate, which are used to clamp the workpiece to be tested placed between the clamping blocks on both sides. In order to achieve the clamping of workpieces to be tested with different shapes, the clamping blocks and the fixture base plate are slidably matched, and the spacing can be adjusted to adapt to test workpieces of different sizes.

[0075] The working principle of the detection device is as follows: the workpiece to be tested is placed on the workpiece fixture 500, and the workpiece to be tested is clamped by the workpiece fixture 500. The position of the stylus unit 300 is adjusted by the three-axis moving mechanism 200, so that the stylus unit 300 is located above the workpiece to be tested. The surface of the test area of ​​the workpiece to be tested is scanned by the laser scanner 29; the control unit constructs a three-dimensional model of the workpiece to be tested based on the scanning results of the laser scanner 29, and then identifies the surface structural features of the workpiece to be tested; then the path of the stylus 20 is planned based on the identified surface structural features of the workpiece to be tested; and then the stylus 20 is controlled to move along the planned scratch path and apply the test load; thus, the scratch test is performed according to the set parameters.

[0076] Specific: such as Figure 6 As shown, before the test, first determine the starting point of the test, and set the test area according to the starting point, use the laser scanner 29 to perform contour scanning on the test area of ​​the workpiece to be tested, and collect point cloud data; reconstruct the three-dimensional model of the workpiece to be tested in the control unit based on the point cloud data, and judge the type of the test area of ​​the workpiece to be tested according to the reconstructed three-dimensional model, and plan the specific moving path of the stylus (that is, according to the shape characteristics of the workpiece surface scanned by the laser scanner 29, discrete points are obtained, and the path equation of the stylus on the workpiece surface is fitted). Linear loading is performed while the stylus 20 moves (adjusting the angle and position of the stylus can make the stylus always perpendicular to the workpiece surface), and the data during the test process is monitored, and the critical bonding force of the surface coating of the workpiece test path is comprehensively judged based on this.

[0077] During the test, the scratching process is monitored by a high-definition camera 28; after the scratching is completed, the scratch morphology is observed by a high-power optical microscope 32 and a low-power optical microscope 33 to determine the critical bonding strength of the coating.

[0078] As an example, when there are an acoustic emission sensor 19 and a lateral force sensor, the critical bonding force of the coating can be comprehensively judged by the scratch morphology, the signal of the acoustic emission sensor 19 and the signal of the lateral force sensor.

[0079] Embodiment 2:

[0080] Based on the above-mentioned embodiment 1, this embodiment provides a method for using the detection device to detect scratches on the surface coating of a workpiece. Figure 7 As shown:

[0081] S1. Place the workpiece to be tested on the fixture bottom plate of the workpiece fixture 500 and clamp the workpiece; then start the device, check the detection device itself, and enter the test preparation stage.

[0082] S2. Set the device test parameters (movement speed, area size, test point spacing (test point spacing for three-dimensional scanning), test path length, etc.) on the host computer, adjust the position of the stylus unit 300 through the three-axis moving mechanism 200, and move the stylus unit 300 to the center of the test area.

[0083] S3. Start the test: drive the X-axis moving unit and the Y-axis moving unit to drive the observation unit 400 to move and traverse the test area; during the traversal process, the laser scanner 29 quickly scans the test area, so that the position information of each test point in the test area is recorded to obtain "point cloud" data; "point cloud" is a collection of a large number of three-dimensional coordinate points, which can intuitively represent the surface morphology of the test area.

[0084] S4. Filter and optimize the noise or error of the acquired original "point cloud" data, remove abnormal points, and improve data quality; then extract features such as edges, planes, specific shapes, etc. from the "point cloud" data after removing abnormal points, and perform surface shape recognition of the workpiece to be measured for subsequent analysis and decision-making.

[0085] S5. Automatically determine the scratch test route based on the extracted surface features of the test area, calculate the normal vector by local plane fitting, and generate a motion trajectory sequence of the stylus 20, which contains both the position and end contact point coordinate information of the stylus 20.

[0086] S6. Move the stylus 20 to the initial position of the trajectory sequence through the three-axis moving mechanism 200, drive the stylus 20 to move according to the generated motion trajectory sequence to perform a scratch test, and perform linear loading on the stylus 20 at the same time.

[0087] During the test, the high-definition camera 28 in the observation unit 400 records the test process; the host computer automatically records the signals output by the lateral force sensor and the acoustic emission sensor 19, that is, the lateral force sensor and the acoustic emission sensor 19 are used to record the friction force and sound during the scratch test respectively.

[0088] S7. After the scratch test is completed, use a high-power optical microscope 32 and a low-power optical microscope 33 to identify the scratch morphology; adjust the lifting rack 25 through the lifting rack driving motor 30, and then adjust the height of the turret 31, so that the high-power optical microscope 32 and the low-power optical microscope 33 display the picture so that the object image in the microscope is clear, and then used for critical bonding force analysis.

[0089] S8. Comprehensive judgment of coating damage: Comprehensively judge the critical bonding force based on the scratch morphology observed by microscope, the acoustic emission detection signal, and the friction force detected by the lateral force sensor.

[0090] S9. After the test is completed, the host computer software records the test data.

[0091] The above test process can be completed automatically under the control of the control unit.

[0092] In the above S8, the coating damage phenomenon in the scratch test is comprehensively judged mainly from the following three aspects:

[0093] (1) Changes in microscopic scratch morphology: directly reflect the actual damage to the coating surface, including the depth, width, and shape of the scratches.

[0094] (2) Acoustic emission detection signal mutation: Acoustic emission technology can monitor the micro-crack extension and internal strain of the coating during the scratching process in real time. Its signal mutation indicates the instantaneous state of damage, which is crucial for predicting the critical point of coating damage.

[0095] (3) Sudden change in friction coefficient: The change in the friction coefficient of the scratch needle during the scratch test can reflect the change in the bonding force of the coating surface.

[0096] Based on these three factors, the critical bonding strength of the coating is determined in the order of priority: microscratch morphology change - acoustic emission detection signal mutation - friction coefficient mutation.

[0097] Figure 8 The detailed process of the detection device from workpiece scanning to path generation (i.e., the above steps S4 and S5) is demonstrated, which can be roughly divided into three parts: data acquisition, data processing, and path planning. Data acquisition uses a laser sensor to perform three-dimensional scanning to obtain point cloud data, and automatically generates test points and plans the scanning path after determining the starting point. In the data processing stage, gridding and interpolation algorithms are used to fill holes, a suitable filtering algorithm is selected for denoising, and preprocessed surface contour data is output. Based on the preprocessed data, regional features are extracted, test paths are generated by fitting, and the stylus posture vector is generated.

[0098] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A device for detecting the bonding strength and scratches of coatings on a workpiece surface, characterized in that: include: A three-axis moving mechanism (200), a stylus unit (300), an observation unit (400) and a workpiece fixture (500); The scribing needle unit (300) is mounted on the three-axis moving mechanism (200), and can move along the planned scribing needle moving path on the coating surface of the workpiece to be tested, use the scribing needle to scratch the coating surface of the workpiece to be tested, and apply a test load to the workpiece to be tested; The observation unit (400) is installed on the three-axis moving mechanism (200) and can identify the surface shape of the workpiece to be measured and is used to plan the moving path of the stylus. At the same time, the observation unit (400) can also observe the morphology of scratches on the coating surface of the workpiece to be measured caused by the stylus unit. The workpiece clamp (500) is used for clamping a workpiece to be tested.

2. The workpiece surface coating bonding strength scratch detection device according to claim 1, characterized in that: Define the vertical direction in the three-axis moving mechanism as the Z direction; The scribing needle unit (300) comprises: a Z-axis rotation motor (17), a scribing needle support rod (18), a scribing needle (20) and a scribing needle swing motor (23); The stylus unit (300) is mounted on the three-axis moving mechanism (200) via a stylus unit mounting support seat (21); the stylus mounting seat (24) is supported on the stylus unit mounting support seat (21) via a Z-axis rotating bearing (22); a Z-axis rotating motor (17) is arranged on the stylus unit mounting support seat (21); an output shaft of the Z-axis rotating motor (17) is connected to the stylus mounting seat (24) for driving the stylus mounting seat (24) to rotate around the Z direction; The stylus mounting rod is supported on the stylus mounting seat (24) through a bearing, and the axis of the stylus mounting rod is perpendicular to the output shaft of the Z-axis rotating motor (17); the stylus (20) is connected to the stylus mounting rod through the stylus supporting rod (18); the stylus swinging motor (23) is installed on the stylus mounting seat (24) and is used to drive the stylus mounting rod to rotate around its own axis, thereby driving the stylus (20) to swing.

3. The workpiece surface coating bonding strength scratch detection device as claimed in claim 2, characterized in that: The stylus unit further comprises a longitudinal force sensor for monitoring the longitudinal load applied by the stylus to the workpiece to be tested and a transverse force sensor for monitoring the friction force during the scratch test.

4. The workpiece surface coating bonding strength scratch detection device as claimed in claim 2 or 3, characterized in that: An acoustic emission sensor (19) is installed on the scribing needle and is used to monitor the sound signal during the scribing needle working process.

5. The workpiece surface coating bonding strength scratch detection device as claimed in claim 1, characterized in that: The observation unit (400) comprises: an observation unit mounting seat (26), a lifting mechanism, a camera module, a laser scanner (29) and a scratch observation module; The observation unit mounting seat (26) is connected to the three-axis moving mechanism (200); The camera module is mounted on the observation unit mounting seat (26) via a flexible rod (27); The lifting mechanism is mounted on the observation unit mounting seat (26); the lifting mechanism is connected to a turret (31); a laser scanner and a scratch observation module are mounted on the turret (31); the laser scanner is used to perform laser scanning on the surface of the workpiece to be measured, thereby constructing and observing the surface shape of the workpiece to be measured; and the scratch observation module is used to observe the scratch morphology on the surface of the workpiece to be measured.

6. The workpiece surface coating bonding strength scratch detection device as claimed in claim 5, characterized in that: The lifting mechanism comprises: a lifting rack (25), a gear, and a lifting rack driving motor (30); The lifting rack drive motor (30) is arranged on the side of the observation unit mounting seat (26), the gear is coaxially connected to the output shaft of the lifting rack drive motor (30), and the vertically arranged lifting rack (25) is meshed with the gear; The lower end of the lifting rack (25) is connected to the turret (31).

7. The workpiece surface coating bonding strength scratch detection device according to any one of claims 1 to 3, characterized in that: The three-axis moving mechanism (200) comprises: a support frame (100), an X-direction moving unit, a Y-direction moving unit and a Z-direction moving unit; The vertical direction is the Z direction, the width direction of the support frame (100) is the X direction, and the length direction is the Y direction; The support frame (100) comprises a base (16) and four upright posts (15) distributed in a rectangular shape on the base (16); the tops of two adjacent upright posts (15) are connected by a transverse connecting piece to form a top frame; The Y-direction moving unit is arranged on the top frame, the X-direction moving unit is installed on the Y-direction moving unit and can move along the Y-direction under the drive of the Y-direction moving unit; the Z-direction moving unit is installed on the X-direction moving unit and can move along the X-direction under the drive of the X-direction moving unit; the stylus unit (300) is installed on the Z-direction moving unit and can move along the Z-direction under the drive of the Z-direction moving unit.

8. A method for detecting scratches on the bonding strength of a workpiece surface coating, characterized in that: Using the detection device described in any one of claims 1 to 7 above, the steps of the detection method are: S1. The workpiece fixture (500) is used to clamp the workpiece to be tested; S2. The three-axis moving mechanism (200) moves the stylus unit (300) and the observation unit (400) to a set position; S3. The observation unit (400) is driven to move by the three-axis moving mechanism (200) to identify the surface shape of the test area of ​​the workpiece to be tested; S5. Planning the needle movement path according to the identified surface shape of the test area; S6. The three-axis moving mechanism (200) and the scratching needle unit (300) drive the scratching needle (20) to move along the moving path of the scratching needle to perform a scratch test; during the test, the observation unit (400) photographs the test process; S7. After the scratch test is completed, the observation unit (400) identifies the scratch morphology of the workpiece to be tested; S8. Determine the critical bonding strength based on the scratch morphology.

9. The method for detecting the bonding strength of a workpiece surface coating by scratches according to claim 8, characterized in that: In S3, in the observation unit (400), a laser sensor is used to perform a three-dimensional scan on the surface of the test area of ​​the workpiece to be measured to obtain point cloud data, and then the surface shape of the workpiece to be measured is recognized.

10. The method for detecting the bonding strength of a workpiece surface coating by scratches according to claim 8, characterized in that: During the scratch test, the friction force of the sliding needle and the sound signal during the scratching process are monitored in real time; The critical bonding strength of the coating is determined according to the priority order of scratch morphology change-sound signal mutation-friction coefficient mutation.

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