Self-adaptive hollow turbine blade ultrasonic wall thickness measuring method

Abstract

The invention discloses a self-adaptive hollow turbine blade ultrasonic wall thickness measurement method, and belongs to the field of aero-engine repair, a measurement model of a blade is imported into a measurement system, a robot is controlled by an upper computer to find a measurement point position and a motion trail of the robot, a water distance is fixed at a 25.4 mm position, and an ultrasonic wall thickness measurement result is obtained. The upper computer controls the robot to find a first point position for ultrasonic measurement data collection, the robot operates the blade clockwise, the next point is measured, after measurement of all the point positions is finished, the robot grabs the blade, and a blow-drying device is adopted to dry moisture on the surface of the blade; and the dried blade is put back into the material disc, and then the next blade is measured. The method has the beneficial effects that the movement track of the robot is determined by calculating the coordinates and the normal of the three-dimensional model measurement point, the ultrasonic wall thickness measurement of the self-adaptive hollow turbine blade is realized through an upper computer control program, and the measurement efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of aero-engine repair, and in particular to an adaptive ultrasonic wall thickness measurement method for hollow turbine blades. Background Technology

[0002] Blades are critical components of aero engines and are the main power-generating components of aero engines. They are subjected to high-temperature environments during operation. In order to withstand high temperatures, most blades adopt a thin-walled hollow structure design. The blade wall thickness directly affects the engine performance. In order to ensure product quality, there is an urgent need to invent an adaptive ultrasonic wall thickness measurement method for hollow turbine blades.

[0003] Currently, the wall thickness measurement of hollow blades is generally done using conventional ultrasonic and industrial TC methods. Conventional manual ultrasonic thickness measurement is inefficient and has large measurement errors, while industrial TC thickness measurement is also inefficient. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an adaptive ultrasonic wall thickness measurement method for hollow turbine blades.

[0005] The objective of this invention is achieved through the following technical solution: an adaptive ultrasonic wall thickness measurement method for hollow turbine blades, comprising the following two steps: S1: Adaptive measurement method, the adaptive measurement method comprising the following steps: S11: Calculate the coordinates and normals of the measurement points in the 3D model, analyze the measurement section of the 3D model of the blade, establish a coordinate system for each measurement point through the 3D model, and obtain the vertical normal of each measurement point. S12: Determine the robot's motion trajectory. First, establish the HOME position of the robot relative to the installation center reference point, and at the same time, give the coordinates of the probe's measurement point to establish the starting point and ending point of the measurement. During the measurement process, the coordinates of these two points remain unchanged, and the trajectory of the measurement point is fixed. Determine the theoretical normal according to step S11. Each normal has two coordinates, one on the blade and the other on the outer extension normal. Set the length of the normal. The coordinate points on the outer extension normal coincide with the probe measurement points. Compile all coordinate points and send them to the robot. Starting from the position of the blade back cavity, rotate clockwise one revolution to obtain the robot's motion trajectory. S13: Compile the host control program. Based on the coordinates of the measurement points and the robot's motion trajectory obtained in steps S11 and S12, compile the host control program. S2: Blade wall thickness measurement method, the blade wall thickness measurement method includes the following steps: S21: Make standard gauge blocks. Determine the range of standard gauge blocks for thickness measurement based on the upper and lower limits of the blade wall thickness. Select a material of the same type as the blade and process and make stepped test blocks. S22: Solidify the calibrated ultrasonic thickness measurement parameters; Using the water immersion ultrasonic method, a narrow water immersion point focusing probe is selected for non-contact measurement. The probe is fixed in place, and the host computer controls the robot to pick up the standard gauge block according to the set path and perform measurement on the focal measurement surface. Using the standard measurement block from step S21, the equipment parameters are adjusted using standard measurement blocks with the maximum and minimum thicknesses. The measurement accuracy is verified by comparing with the known thickness. The initial value of the ultrasonic measurement system and the sound velocity of the blade are calibrated, and the calibrated ultrasonic thickness measurement parameters are solidified and saved in the equipment. S23: Blade wall thickness measurement. Using the same parameters as in step S22, the blade on the tray is picked up by the robot controlled by the host computer. The measurement starts from the back cavity of the blade and rotates clockwise to measure the next point. The wall thickness value of the measurement point is collected by an ultrasonic thickness gauge. After the measurement is completed, the robot picks up the blade and uses a drying device to dry the water on the surface of the blade. After drying, the blade is placed back into the tray.

[0006] In step S12, the length of the normal is the length of the region where the probe energy is most concentrated.

[0007] In step S12, the coordinates are compiled using the C# programming language.

[0008] In step S13, when compiling the upper-level control program, the robot installation coordinate point is used as the reference point, the motion trajectory is imported, control instructions are written, automatic measurement mode and arbitrary point measurement mode are used, the batch number and ultrasonic measurement data are imported, the data is stored in the call function, and the software is integrated into a whole to form the equipment's measurement software.

[0009] The thickness of the stepped test block is between 0.50 mm and 2.00 mm.

[0010] The stepped test block has four specifications with thicknesses of 0.50mm, 1.00mm, 1.50mm and 2.00mm respectively.

[0011] In step S13, the host control program is written using the C# programming language.

[0012] The present invention has the following advantages: 1. This invention calculates the coordinates and normals of measurement points in a three-dimensional model, determines the robot's motion trajectory, and realizes adaptive ultrasonic wall thickness measurement of hollow turbine blades through a host computer control program. It has high measurement efficiency and high measurement reliability, and requires no personnel on duty. 2. A stepped standard gauge block is used, and the standard gauge block and the blade tenon shape are connected by set screws to facilitate robot clamping and realize automated calibration; 3. This invention uses a water immersion ultrasonic point focusing probe with a narrow acoustic beam for non-contact measurement, which reduces the impact of surface roughness, complex shape, and poor coupling effect on ultrasonic thickness measurement echoes and improves measurement reliability. Attached Figure Description

[0013] Figure 1 Schematic diagram for confirming normal coordinate calculation Figure 2 For robot simulation test diagram Figure 3 This is a schematic diagram of the installation of standard gauge blocks and blade tenons. Figure 4 This is a schematic diagram of the model of the blade to be tested. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0015] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0016] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0017] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0018] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0019] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] like Figure 1 As shown, an adaptive ultrasonic wall thickness measurement method for hollow turbine blades includes the following two steps: S1: Adaptive measurement method, which includes the following steps: S11: Calculate the coordinates and normals of the measurement points in the 3D model, analyze the measurement section of the 3D model of the blade, establish a coordinate system for each measurement point through the 3D model, and obtain the vertical normal of each measurement point. S12: Determine the robot's motion trajectory. First, establish the HOME position of the robot relative to the installation center reference point. The HOME position is the coordinate position when the robot is powered on for each measurement. At the same time, the coordinates of the probe's measurement point are given, thus establishing the starting point and ending point of the measurement. During the measurement process, the coordinates of these two points remain unchanged, and the trajectory of the measurement point is fixed. Determine the theoretical normal line according to step S11. Each normal line has two coordinates, one on the blade and the other on the outer extension normal line. Set the length of the normal line. In this embodiment, the length of the normal line is the length of the area where the probe's energy is most concentrated. The coordinate points on the outer extension normal line coincide with the probe measurement points. Compile all coordinate points. Preferably, C# is used to compile the coordinates and send them to the robot. Starting from the position of the blade back cavity, rotate clockwise one revolution to obtain the robot's motion trajectory. S13: Compile the upper-level control program. Based on the measurement point coordinates and robot motion trajectory obtained in steps S11 and S12, compile the upper-level control program. In this embodiment, the upper-level control program is compiled using the C# programming language. Specifically, when compiling the upper-level control program, the robot installation coordinates are used as the reference point. The motion trajectory is imported, control instructions are written, automatic measurement mode and arbitrary point measurement mode are enabled, batch number and ultrasonic measurement data are imported, data is stored in the call function, and the software is integrated into a whole to form the equipment's measurement software. S2: Blade wall thickness measurement method, which includes the following steps: S21: Fabricate standard gauge blocks. Determine the range of thickness measurement standard gauge blocks based on the upper and lower limits of the blade wall thickness. Select a material of the same type as the blade and process and fabricate stepped test blocks. Preferably, the thickness of the stepped test blocks is between 0.50mm and 2.00mm. Further, the stepped test blocks have four specifications with thicknesses of 0.50mm, 1.00mm, 1.50mm, and 2.00mm, respectively. In order to cooperate with robot clamping, the standard gauge blocks are designed with tenons similar to those of the hollow turbine blade and are connected to the thickness gauge blocks by set screws. S22: Solidify the calibrated ultrasonic thickness measurement parameters; using the water immersion ultrasonic method, a narrow water immersion point focusing probe is selected for non-contact measurement. The probe is fixed in place, and the host computer controls the robot to pick up the standard gauge block according to the set path and perform measurement on the focal measurement surface. Using the standard measurement block from step S21, the equipment parameters are adjusted using standard measurement blocks with the maximum and minimum thicknesses. The measurement accuracy is verified by comparing with the known thickness. In this embodiment, standard gauge blocks with thicknesses of 0.50mm and 2.00mm are used to adjust the equipment parameters and compare with standard gauge blocks with known thicknesses of 1.00mm and 1.50mm. This calibrates the initial value of the ultrasonic measurement system and the sound velocity of the blade. The calibrated ultrasonic thickness measurement parameters are solidified and stored in the equipment. S23: Blade wall thickness measurement. Using the same parameters as in step S22, the blade on the tray is picked up by the robot controlled by the host computer. The measurement starts from the back cavity of the blade and rotates clockwise to measure the next point. The wall thickness value of the measurement point is collected by an ultrasonic thickness gauge. After the measurement is completed, the robot picks up the blade and uses a drying device to dry the water on the surface of the blade. After drying, the blade is placed back into the tray.

[0021] The working process of this invention is as follows: Taking a high-pressure turbine blade of a certain type of engine as an example, the blade has three sections, and each section has 14 internal cavity points on each surface, for a total of 42 points that need to be measured. The measurement steps are as follows: First, the measurement model of the blade is imported into the measurement system. The host computer controls the robot to find the measurement points and the robot's movement trajectory. The water distance is fixed at 25.4mm (at this time, the focus is on the measurement section, and the energy is the highest). The calibrated ultrasonic thickness measurement program 10DW is called, the ultrasonic thickness gauge model is 72DLPLUS, and the robot is a KUKA model. Product No.: KR10R1100-2. The robot grasps the blade. The host computer controls the robot to locate the first point (the air inlet side chamber on the blade back) for ultrasonic measurement data acquisition. The robot rotates the blade clockwise to measure the next point. After measuring 42 points, the robot grasps the blade and uses a drying device to dry the surface moisture. In this embodiment, the drying device is existing technology; those skilled in the art can choose a conventional method according to their needs. Preferably, compressed air is used to dry the surface moisture of the blade. The dried blade is placed back in the material tray before measuring the next blade. The measurement data and waveform are maintained in the measurement system. See details below. Figure 4 Measurement model diagram.

[0022] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An adaptive ultrasonic wall thickness measurement method for hollow turbine blades, characterized in that: It includes the following two steps: S1: Adaptive measurement method, the adaptive measurement method comprising the following steps: S11: Calculate the coordinates and normals of the measurement points in the 3D model, analyze the measurement section of the 3D model of the blade, establish a coordinate system for each measurement point through the 3D model, and obtain the vertical normal of each measurement point. S12: Determine the robot's motion trajectory. First, establish the HOME position of the robot relative to the installation center reference point, and at the same time, give the coordinates of the probe's measurement point to establish the starting point and ending point of the measurement. During the measurement process, the coordinates of these two points remain unchanged, and the trajectory of the measurement point is fixed. Determine the theoretical normal according to step S11. Each normal has two coordinates, one on the blade and the other on the outer extension normal. Set the length of the normal. The coordinate points on the outer extension normal coincide with the probe measurement points. Compile all coordinate points and send them to the robot. Starting from the position of the blade back cavity, rotate clockwise one revolution to obtain the robot's motion trajectory. S13: Compile the host control program. Based on the coordinates of the measurement points and the robot's motion trajectory obtained in steps S11 and S12, compile the host control program. S2: Blade wall thickness measurement method, the blade wall thickness measurement method includes the following steps: S21: Make standard gauge blocks. Determine the range of standard gauge blocks for thickness measurement based on the upper and lower limits of the blade wall thickness. Select a material of the same type as the blade and process and make stepped test blocks. S22: Solidify the calibrated ultrasonic thickness measurement parameters; Using the water immersion ultrasonic method, a narrow water immersion point focusing probe is selected for non-contact measurement. The probe is fixed in place, and the host computer controls the robot to pick up the standard gauge block according to the set path and perform measurement on the focal measurement surface. Using the standard measurement block from step S21, the equipment parameters are adjusted using standard measurement blocks with the maximum and minimum thicknesses. The measurement accuracy is verified by comparing with the known thickness. The initial value of the ultrasonic measurement system and the sound velocity of the blade are calibrated, and the calibrated ultrasonic thickness measurement parameters are solidified and saved in the equipment. S23: Blade wall thickness measurement. Using the same parameters as in step S22, the blade on the tray is picked up by the robot controlled by the host computer. The measurement starts from the back cavity of the blade and rotates clockwise to measure the next point. The wall thickness value of the measurement point is collected by an ultrasonic thickness gauge. After the measurement is completed, the robot picks up the blade and uses a drying device to dry the water on the surface of the blade. After drying, the blade is placed back into the tray.

2. The adaptive ultrasonic wall thickness measurement method for hollow turbine blades according to claim 1, characterized in that: In step S12, the length of the normal is the length of the region where the probe energy is most concentrated.

3. The adaptive ultrasonic wall thickness measurement method for hollow turbine blades according to claim 1 or 2, characterized in that: In step S12, the coordinates are compiled using the C# programming language.

4. The adaptive ultrasonic wall thickness measurement method for hollow turbine blades according to claim 1, characterized in that: In step S13, when compiling the upper-level control program, the robot installation coordinate point is used as the reference point, the motion trajectory is imported, control instructions are written, automatic measurement mode and arbitrary point measurement mode are used, the batch number and ultrasonic measurement data are imported, the data is stored in the call function, and the software is integrated into a whole to form the equipment's measurement software.

5. The adaptive ultrasonic wall thickness measurement method for hollow turbine blades according to claim 1, characterized in that: The thickness of the stepped test block is between 0.50 mm and 2.00 mm.

6. The adaptive ultrasonic wall thickness measurement method for hollow turbine blades according to claim 5, characterized in that: The stepped test block has four specifications with thicknesses of 0.50mm, 1.00mm, 1.50mm and 2.00mm respectively.

7. An adaptive ultrasonic wall thickness measurement method for hollow turbine blades according to claim 1 or 4, characterized in that: In step S13, the host control program is written using the C# programming language.

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