A high-precision defect detection method and system for a precision injection mold of gears

Abstract

The present invention relates to the technical field of gear mold detection, and specifically to a high-precision detection method and system for defects of a gear precision injection mold, including: dividing the tooth profile cavity into a tooth top space area and a tooth surface space area, setting first ultrasonic phased array detection parameters and second ultrasonic phased array detection parameters, respectively collecting ultrasonic phased array data of the tooth profile cavity to obtain first overall ultrasonic phased array data and second overall ultrasonic phased array data; extracting tooth top ultrasonic phased array data and tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and second overall ultrasonic phased array data, and constructing a tooth top area feature vector extraction strategy and a tooth surface area feature vector extraction strategy to extract a tooth top area feature vector and a tooth surface area feature vector, detecting defects of the tooth profile cavity of the gear precision injection mold, and obtaining a defect influence degree index for processing decisions. The present invention improves the detection accuracy of internal defects of the gear injection mold.

Description

Technical Field

[0001] The present invention relates to the technical field of gear mold detection, and specifically to a high-precision detection method and system for defects of a gear precision injection mold. Background Art

[0002] In modern manufacturing, gears, as key transmission components, are widely used in many fields such as automobiles, aerospace, and mechanical engineering. The quality and performance of gears directly affect the operating efficiency and reliability of the entire mechanical equipment. And gear precision injection molds play a crucial role in the gear manufacturing process, and their quality determines the accuracy and quality of the produced gears.

[0003] At present, for the detection technology of gear injection molds, most research and applications mainly focus on surface defect detection. For example, common vision detection technology collects mold surface images through a high-resolution camera and uses image recognition algorithms to identify surface defects such as scratches, cracks, and wear. However, internal defects of injection molds cannot be ignored either, which will increase the risk of mold damage and have a significant impact on the production of injection parts.

[0004] Existing gear injection mold defect detection technologies lack effective methods for detecting internal defects. Internal defects of the mold, such as internal cracks, pores, and inclusions, are difficult to be detected in time by existing surface detection means. During the long-term use of the mold, these internal defects will gradually expand under the action of stress, resulting in a decrease in the structural strength of the mold and ultimately leading to premature failure of the mold, which not only increases production costs but also may affect the production schedule and product quality. In addition, the tooth-shaped cavities of gear precision injection molds often contain several internal grooves and tooth-shaped protrusions, which interfere with the propagation and reflection of detection signals, and general ultrasonic flaw detection or X-ray detection means often do not conduct comprehensive detection for the complex geometric shapes of the molds.

[0005] Therefore, a high-precision detection method and system for defects of a gear precision injection mold are proposed. Summary of the Invention

[0006] The object of the present invention is to provide a method and system for high-precision detection of defects in a gear precision injection mold. By dividing the tooth profile cavity into a tooth top space region and a tooth surface space region, setting the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters, and respectively collecting ultrasonic phased array data for the tooth profile cavity, the first overall ultrasonic phased array data and the second overall ultrasonic phased array data are obtained; extracting the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and second overall ultrasonic phased array data, and constructing a tooth top region feature vector extraction strategy and a tooth surface region feature vector extraction strategy, extracting the tooth top region feature vector and the tooth surface region feature vector, detecting defects in the tooth profile cavity of the gear precision injection mold, and obtaining a defect influence degree index for processing decision-making. The present invention improves the detection accuracy of internal defects in the gear injection mold.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for high-precision detection of defects in a gear precision injection mold, comprising:

[0009] Obtaining a three-dimensional model of the tooth profile cavity of the gear precision injection mold, and dividing the three-dimensional model of the tooth profile cavity into a tooth top space region and a tooth surface space region;

[0010] Setting the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters for the tooth top space region and the tooth surface space region;

[0011] Respectively collecting ultrasonic phased array data for the tooth profile cavity of the gear precision injection mold according to the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters, to obtain the first overall ultrasonic phased array data and the second overall ultrasonic phased array data;

[0012] Preprocessing the first overall ultrasonic phased array data and the second overall ultrasonic phased array data; according to the coordinate boundaries of the tooth top space region and the tooth surface space region, respectively extracting the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and second overall ultrasonic phased array data;

[0013] Constructing a tooth top region feature vector extraction strategy and a tooth surface region feature vector extraction strategy, and based on the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data, extracting the tooth top region feature vector and the tooth surface region feature vector;

[0014] Detecting defects in the tooth profile cavity of the gear precision injection mold according to the tooth top region feature vector and the tooth surface region feature vector, obtaining a defect influence degree index, and making a processing decision according to the defect influence degree index.

[0015] Further, obtain the three-dimensional model of the tooth profile cavity, and establish a coordinate system with the corresponding gear center axis as the axis. According to the geometric information of the tooth profile cavity, determine the tooth tip space region and the tooth surface space region, including:

[0016] ;

[0017] Among them, represents the tooth tip space region, represents the tooth surface space region, represents the three-dimensional coordinates, represents the tooth tip circle radius, represents the thickness of the tooth profile cavity, represents the root circle radius.

[0018] Further, the detection parameters include the step spacing, the focused sound beam angle, the focused sound beam depth, and the number of array elements.

[0019] Further, extracting the tooth tip ultrasonic phased array data and the tooth surface ultrasonic phased array data includes:

[0020] Extracting the tooth tip ultrasonic phased array data from the first overall ultrasonic phased array data is expressed as:

[0021] ;

[0022] Among them, represents the tooth tip ultrasonic phased array data, represents the first overall ultrasonic phased array data, represents the tooth tip space region mask function, represents the tooth tip space region;

[0023] Extracting the tooth surface ultrasonic phased array data from the second overall ultrasonic phased array data is expressed as:

[0024] ;

[0025] Among them, represents the tooth surface ultrasonic phased array data, represents the second overall ultrasonic phased array data, represents the tooth surface space region mask function, represents the tooth surface space region.

[0026] Further, the extraction strategy of the tooth tip region feature vector includes: obtaining the amplitude of the echo signal in the tooth tip spatial region to extract the echo intensity feature, obtaining the intensity change of the echo signal to extract the acoustic wave attenuation feature, obtaining the propagation time of the ultrasonic wave and calculating the sound speed to extract the sound speed change feature, obtaining the echo signal intensities in different directions to calculate the scattering energy and extract the scattering energy feature, and constructing the tooth tip region feature vector according to the echo intensity feature, the acoustic wave attenuation feature, the sound speed change feature, and the scattering energy feature; the extraction strategy of the tooth surface region feature vector includes: performing Fourier transform on the echo signal in the tooth surface spatial region, analyzing the energy distribution of different frequency components to extract the spectral energy feature, analyzing the scattering feature of the echo signal to calculate the scattering coefficient and extract the scattering coefficient feature, analyzing the distribution matrix of the signal intensities at different angles to extract the multi-angle beam feature, analyzing the phase of the echo signal to calculate the phase shift and extract the phase shift feature, and constructing the tooth surface region feature vector according to the spectral energy feature, the scattering coefficient feature, the multi-angle beam feature, and the phase shift feature.

[0027] Further, defect detection of the tooth profile cavity of the precision injection mold for gears according to the tooth tip region feature vector and the tooth surface region feature vector includes:

[0028] Normalize each eigenvalue in the tooth tip region feature vector and the tooth surface region feature vector;

[0029] Calculate the first defect influence degree index according to the normalized tooth tip region feature vector;

[0030] Calculate the second defect influence degree index according to the normalized tooth surface region feature vector;

[0031] Weightedly combine the first defect influence degree index and the second defect influence degree index to obtain the defect influence degree index.

[0032] Further, processing decisions according to the defect influence degree index include:

[0033] When the defect influence degree index is less than the first threshold, use and maintain the tooth profile cavity of the precision injection mold for gears at a preset period;

[0034] When the defect influence degree index is greater than or equal to the first threshold and less than or equal to the second threshold, increase the regular detection frequency of the tooth profile cavity of the precision injection mold for gears;

[0035] When the defect influence degree index is greater than the second threshold, for repairable defects, perform targeted repairs, and for non-repairable defects, replace the tooth profile cavity of the precision injection mold for gears.

[0036] A high-precision defect detection system for a gear precision injection mold, comprising:

[0037] A region division module is used to obtain a three-dimensional model of a tooth profile cavity of a gear precision injection mold, and to divide the three-dimensional model of the tooth profile cavity into a tooth top space region and a tooth surface space region;

[0038] a data acquisition module, setting a first ultrasonic phased array detection parameter and a second ultrasonic phased array detection parameter for the tooth top space area and the tooth surface space area; performing ultrasonic phased array data acquisition on the tooth profile cavity of the gear precision injection mold according to the first ultrasonic phased array detection parameter and the second ultrasonic phased array detection parameter, respectively, to obtain first overall ultrasonic phased array data and second overall ultrasonic phased array data;

[0039] a regional data extraction module, preprocessing the first overall ultrasonic phased array data and the second overall ultrasonic phased array data; extracting tooth top ultrasonic phased array data and tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and the second overall ultrasonic phased array data according to the coordinate boundaries of the tooth top space region and the tooth surface space region;

[0040] A regional feature extraction module is used to construct a tooth top regional feature vector extraction strategy and a tooth surface regional feature vector extraction strategy, and to extract a tooth top regional feature vector and a tooth surface regional feature vector based on the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data;

[0041] The defect detection decision module performs defect detection on the tooth profile cavity of the gear precision injection mold according to the tooth top area feature vector and the tooth surface area feature vector, obtains a defect influence degree index, and makes a processing decision according to the defect influence degree index.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] 1. By dividing the three-dimensional model of the gear precision injection mold tooth profile cavity into the tooth top and tooth surface spatial regions, and setting different ultrasonic phased array detection parameters to collect data, this differentiated detection strategy fully considers the differences in geometry and stress distribution between the tooth top and tooth surface regions, and can adjust the detection parameters in a targeted manner to improve the accuracy and sensitivity of the detection. Through precise spatial area division and differentiated detection parameter settings, the detection process can more accurately adapt to the structural characteristics of the tooth profile cavity, realize accurate detection of the characteristics of different regions of the gear mold, and can more accurately identify defects inside the mold, thereby improving the reliability and comprehensiveness of the detection.

[0044] 2. Feature vector extraction strategies for the tooth tip region and the tooth surface region were constructed respectively. This dual feature vector extraction strategy fully considers the physical property differences between the two regions. Through different feature extraction methods, it can capture defect information more comprehensively, improve the recognition ability for irregular defects, and ensure the comprehensiveness and accuracy of detection by extracting multi-dimensional features. The combined use of the two feature vector extraction strategies not only ensures the comprehensiveness of detection but also the pertinence of detection for each region. Through the differential feature extraction strategy, accurate recognition of defect features within different spatial regions is achieved. Especially when facing complex mold shapes and diverse defects, potential information in ultrasonic data can be fully exploited.

[0045] 3. A grading processing decision-making mechanism based on the defect impact degree index was set up. First, the feature vectors of the tooth tip region and the tooth surface region were standardized, the first defect impact degree index and the second defect impact degree index were calculated respectively, and the final defect impact degree index was obtained through weighted combination. A grading processing decision was set in combination with the threshold. This grading mechanism not only provides a quantitative evaluation standard for the defect degree inside the tooth profile cavity of the gear mold but also is directly related to the actual maintenance decision, providing a scientific basis for the maintenance and replacement of the mold, achieving precise management of the defect situation inside the tooth profile cavity, and improving production efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic flow chart of a high-precision defect detection method for a gear precision injection mold of the present invention;

[0047] Figure 2 It is a schematic structural diagram of the tooth profile cavity of the gear precision injection mold of the present invention;

[0048] Figure 3 It is a schematic structural diagram of a high-precision defect detection system for a gear precision injection mold of the present invention.

[0049] In the figure: 1. Tooth profile cavity; 2. Tooth tip circle; 3. Tooth root circle; 4. Center of the circle; 5. Tooth tip space region; 6. Tooth surface space region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0050] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0051] Please refer to Figures 1 to 3, the present invention provides a method and system for high-precision detection of defects in a gear precision injection mold, and the technical solution is as follows: Example 1:

[0052] A method for high-precision detection of defects in a gear precision injection mold, the method process is as Figure 1 shown, including:

[0053] Obtain the three-dimensional model of the tooth profile cavity of the gear precision injection mold, and divide the three-dimensional model of the tooth profile cavity into a tooth top space area and a tooth surface space area;

[0054] Set the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters for the tooth top space area and the tooth surface space area;

[0055] Respectively collect ultrasonic phased array data of the tooth profile cavity of the gear precision injection mold according to the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters to obtain the first overall ultrasonic phased array data and the second overall ultrasonic phased array data;

[0056] Preprocess the first overall ultrasonic phased array data and the second overall ultrasonic phased array data; according to the coordinate boundaries of the tooth top space area and the tooth surface space area, extract the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and the second overall ultrasonic phased array data respectively;

[0057] Construct a tooth top area feature vector extraction strategy and a tooth surface area feature vector extraction strategy, and based on the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data, extract the tooth top area feature vector and the tooth surface area feature vector;

[0058] Perform defect detection on the tooth profile cavity of the gear precision injection mold according to the tooth top area feature vector and the tooth surface area feature vector to obtain a defect influence degree index, and make a processing decision according to the defect influence degree index.

[0059] Further, obtain the three-dimensional model of the tooth profile cavity, establish a coordinate system with the corresponding gear center axis as the axis, and determine the tooth top space area and the tooth surface space area according to the geometric information of the tooth profile cavity, including:

[0060] ;

[0061] Among them, represents the tooth top space area, represents the tooth surface space area, represents the three-dimensional coordinates, represents the tooth top circle radius, Denotes the thickness of the tooth-shaped cavity Denotes the root circle radius

[0062] As Figure 2 Shown, a structural example diagram of a tooth-shaped cavity 1 is given. The centers 4 of the addendum circle 2 and the root circle 3 are located on the central axis of the gear. The addendum space region 5 and the tooth surface space region 6 in a sector region are shown in the figure. In the entire tooth-shaped cavity 1, the addendum space region 5 is the disk-shaped region between the outer circle of the tooth-shaped cavity 1 and the addendum circle 2, and the tooth surface space region 6 is the serrated region between the addendum circle 2 and the root circle 3

[0063] Determining the addendum space region and the tooth surface space region based on the geometric information of the tooth-shaped cavity effectively improves the locality and pertinence of defect detection, can better detect potential defects for the complex structure of the mold, and enhances the accuracy and reliability of the detection results

[0064] Furthermore, the detection parameters include the step spacing, the focused beam angle, the focused beam depth, and the number of array elements

[0065] This embodiment is for defect detection of an injection mold for a plastic gear of a certain automotive transmission. The mold is made of P20 mold steel. The mold cavity is a straight gear structure, with a cavity diameter of 98 mm, an addendum circle diameter of 78 mm, a root circle diameter of 66 mm, and a tooth-shaped cavity thickness of 25 mm. During the production process, it is found that there are local dimensional deviations in the injection-molded parts, and non-destructive testing of the mold is required to evaluate its internal state. Table 1 shows the specific parameter settings of the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters

[0066] Table 1 Detection parameter settings

[0067]

[0068] By setting the step spacing, the focused beam angle, the focused beam depth, and the number of array elements, the internal information of the mold can be obtained more accurately, the detail level of the detection is improved, smaller defects can be detected, and the quality and reliability of the data are enhanced

[0069] Furthermore, extracting the addendum ultrasonic phased array data and the tooth surface ultrasonic phased array data includes

[0070] Extracting the addendum ultrasonic phased array data from the first overall ultrasonic phased array data is expressed as

[0071] ;

[0072] Wherein Denotes the addendum ultrasonic phased array data Denotes the first overall ultrasonic phased array data represents the tooth tip space region mask function, representing the tooth tip space region;

[0073] Extracting the tooth surface ultrasonic phased array data from the second overall ultrasonic phased array data is expressed as:

[0074] ;

[0075] wherein, represents the tooth surface ultrasonic phased array data, represents the second overall ultrasonic phased array data, represents the tooth surface space region mask function, representing the tooth surface space region.

[0076] By extracting the ultrasonic phased array data of the tooth tip and tooth surface space regions, the defects in each region can be analyzed independently, avoiding data interference between regions. For a gear mold with a complex structure, it ensures the accuracy of subsequent feature extraction, provides a reliable data basis for defect detection, and enables detailed detection in each key region.

[0077] Furthermore, the tooth tip region feature vector extraction strategy includes: obtaining the amplitude of the echo signal in the tooth tip space region to extract the echo intensity feature, obtaining the intensity change of the echo signal to extract the acoustic wave attenuation feature, obtaining the propagation time of the ultrasonic wave and calculating the sound speed to extract the sound speed change feature, obtaining the echo signal intensity in different directions to calculate the scattering energy to extract the scattering energy feature, and constructing the tooth tip region feature vector according to the echo intensity feature, the acoustic wave attenuation feature, the sound speed change feature, and the scattering energy feature; the tooth surface region feature vector extraction strategy includes: performing Fourier transform on the echo signal in the tooth surface space region, analyzing the energy distribution of different frequency components to extract the spectral energy feature, analyzing the scattering feature of the echo signal to calculate the scattering coefficient to extract the scattering coefficient feature, analyzing the distribution matrix of the signal intensity at different angles to extract the multi-angle beam feature, analyzing the phase of the echo signal to calculate the phase shift to extract the phase shift feature, and constructing the tooth surface region feature vector according to the spectral energy feature, the scattering coefficient feature, the multi-angle beam feature, and the phase shift feature.

[0078] Constructing feature vector extraction strategies for the tooth tip and tooth surface space regions respectively can comprehensively analyze the state of the mold from different angles, improve the comprehensiveness and accuracy of defect detection, and can also effectively detect internal defects that are not easily detectable. Through different types of signal analysis and feature vector construction, complex ultrasonic echo signals can be transformed into easily understandable feature vectors, enhancing the quantitative analysis ability of mold defects.

[0079] Further, defect detection of the tooth profile cavity of the gear precision injection mold according to the tooth tip region feature vector and the tooth surface region feature vector includes:

[0080] Normalize each eigenvalue in the tooth tip region feature vector and the tooth surface region feature vector;

[0081] Calculate the first defect influence degree index according to the normalized tooth tip region feature vector;

[0082] Calculate the second defect influence degree index according to the normalized tooth surface region feature vector;

[0083] Weight and combine the first defect influence degree index and the second defect influence degree index to obtain the defect influence degree index.

[0084] The calculation of the first defect influence degree index and the second defect influence degree index includes: calculating the relative deviation of each feature component from the corresponding abnormal threshold, and performing weighted summation of the relative deviation and the influence weight to obtain the first defect influence degree index and the second defect influence degree index. The calculation of the relative deviation includes: when the th feature component is greater than the corresponding abnormal threshold , the relative deviation ; when the th feature component is less than or equal to the corresponding abnormal threshold , the relative deviation .

[0085] Table 2 shows the normalization results of the tooth tip region feature vector and the tooth surface region feature vector and the abnormal threshold corresponding to each feature component.

[0086] Table 2 Normalization Results of Region Feature Vectors

[0087]

[0088] By establishing the defect influence degree index through eigenvalue normalization and weighted combination, not only the dimensional difference of different features is considered, but also the importance of each feature is balanced. By calculating the defect influence degree index, an objective basis for defect evaluation can be provided.

[0089] Further, the processing decision according to the defect influence degree index includes:

[0090] When the defect influence degree index is less than the first threshold, use and maintain the tooth profile cavity of the gear precision injection mold at a preset cycle;

[0091] When the defect impact degree index is greater than or equal to the first threshold and less than or equal to the second threshold, increase the regular detection frequency of the tooth-shaped cavity of the gear precision injection mold;

[0092] When the defect impact degree index is greater than the second threshold, for repairable defects, carry out targeted repair, and for non-repairable defects, replace the tooth-shaped cavity of the gear precision injection mold.

[0093] A multi-level processing decision-making mechanism based on thresholds is established, which can provide accurate maintenance and replacement decisions, avoiding over-maintenance, timely discovering and handling serious defects, ensuring that measures can be taken in a timely manner when potential risks occur in the mold, thereby improving the efficiency of mold management and reducing risks, optimizing the mold maintenance strategy, and improving economic benefits.

[0094] In the present invention, by dividing the three-dimensional model of the tooth-shaped cavity into a tooth tip space region and a tooth surface space region, and adopting different ultrasonic phased array detection parameters for data acquisition in different regions, not only the pertinence of detection is improved, but also the complex geometric structure characteristics of the tooth-shaped cavity can be adapted. Through the preprocessing and feature extraction of ultrasonic phased array data in different regions, a dual feature vector extraction strategy is constructed, which can comprehensively capture the defect feature information of each region. Based on the extracted feature vectors, the defect impact degree index is calculated, and a scientific classification decision-making mechanism is established, which can timely discover internal defects and take corresponding maintenance measures. The present invention overcomes the problem of insufficient detection accuracy of internal defects of gear injection molds, realizes high-precision detection of internal defects of tooth-shaped cavities, improves the accuracy and reliability of detection, and provides a scientific basis for the preventive maintenance of molds.

[0095] Embodiment 2:

[0096] This embodiment further provides a high-precision defect detection system for a gear precision injection mold. The system structure is as Figure 3 shown, including:

[0097] A region division module, which acquires the three-dimensional model of the tooth-shaped cavity of the gear precision injection mold and divides the three-dimensional model of the tooth-shaped cavity into a tooth tip space region and a tooth surface space region;

[0098] A data acquisition module, which sets first ultrasonic phased array detection parameters and second ultrasonic phased array detection parameters for the tooth tip space region and the tooth surface space region; respectively acquires ultrasonic phased array data of the tooth-shaped cavity of the gear precision injection mold according to the first ultrasonic phased array detection parameters and the second ultrasonic phased array detection parameters, and obtains first overall ultrasonic phased array data and second overall ultrasonic phased array data;

[0099] The region data extraction module preprocesses the first overall ultrasonic phased array data and the second overall ultrasonic phased array data; according to the coordinate boundaries of the tooth top space region and the tooth surface space region, the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data are respectively extracted from the preprocessed first overall ultrasonic phased array data and the second overall ultrasonic phased array data;

[0100] The region feature extraction module constructs a tooth top region feature vector extraction strategy and a tooth surface region feature vector extraction strategy, and based on the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data, extracts a tooth top region feature vector and a tooth surface region feature vector;

[0101] The defect detection decision module performs defect detection on the tooth profile cavity of the precision injection mold for gears according to the tooth top region feature vector and the tooth surface region feature vector, obtains a defect influence degree index, and makes a processing decision according to the defect influence degree index.

[0102] Further, obtain the three-dimensional model of the tooth profile cavity, and use the corresponding gear center axis as an axis to establish a coordinate system. According to the geometric information of the tooth profile cavity, determine the tooth top space region and the tooth surface space region, including:

[0103] ;

[0104] Among them, represents the tooth top space region, represents the tooth surface space region, represents the three-dimensional coordinates, represents the tooth top circle radius, represents the thickness of the tooth profile cavity, represents the tooth root circle radius.

[0105] Further, the detection parameters include the step spacing, the focused sound beam angle, the focused sound beam depth, and the number of array elements.

[0106] Further, the extraction of the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data includes:

[0107] The extraction of the tooth top ultrasonic phased array data from the first overall ultrasonic phased array data is expressed as:

[0108] ;

[0109] Among them, represents the tooth top ultrasonic phased array data, represents the first overall ultrasonic phased array data, represents the tooth top space region mask function, represents the tooth tip space region;

[0110] Extracting the tooth surface ultrasonic phased array data from the second overall ultrasonic phased array data is expressed as:

[0111] ;

[0112] wherein, represents the tooth surface ultrasonic phased array data, represents the second overall ultrasonic phased array data, represents the tooth surface space region mask function, represents the tooth surface space region.

[0113] Furthermore, the tooth tip region feature vector extraction strategy includes: obtaining the amplitude of the echo signal in the tooth tip space region to extract the echo intensity feature, obtaining the intensity change of the echo signal to extract the acoustic wave attenuation feature, obtaining the propagation time of the ultrasonic wave and calculating the sound speed, extracting the sound speed change feature, obtaining the echo signal intensities in different directions to calculate the scattering energy, extracting the scattering energy feature, and constructing the tooth tip region feature vector according to the echo intensity feature, the acoustic wave attenuation feature, the sound speed change feature, and the scattering energy feature; the tooth surface region feature vector extraction strategy includes: performing Fourier transform on the echo signal in the tooth surface space region, analyzing the energy distribution of different frequency components to extract the spectral energy feature, analyzing the scattering feature of the echo signal to calculate the scattering coefficient and extract the scattering coefficient feature, analyzing the distribution matrix of the signal intensities at different angles to extract the multi-angle beam feature, analyzing the phase of the echo signal to calculate the phase shift and extract the phase shift feature, and constructing the tooth surface region feature vector according to the spectral energy feature, the scattering coefficient feature, the multi-angle beam feature, and the phase shift feature.

[0114] Furthermore, defect detection of the tooth profile cavity of the gear precision injection mold according to the tooth tip region feature vector and the tooth surface region feature vector includes:

[0115] Normalizing each eigenvalue in the tooth tip region feature vector and the tooth surface region feature vector;

[0116] Calculating the first defect influence degree index according to the normalized tooth tip region feature vector;

[0117] Calculating the second defect influence degree index according to the normalized tooth surface region feature vector;

[0118] Weightedly combining the first defect influence degree index and the second defect influence degree index to obtain the defect influence degree index.

[0119] Further, making a processing decision according to the defect influence degree index includes:

[0120] When the defect influence degree index is less than the first threshold, use and maintain the tooth-shaped cavity of the precision injection mold for gears at a preset period;

[0121] When the defect influence degree index is greater than or equal to the first threshold and less than or equal to the second threshold, increase the regular detection frequency of the tooth-shaped cavity of the precision injection mold for gears;

[0122] When the defect influence degree index is greater than the second threshold, for repairable defects, perform targeted repair, and for non-repairable defects, replace the tooth-shaped cavity of the precision injection mold for gears.

[0123] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision defect detection method for a gear precision injection mold, characterized in that: include: Obtaining a three-dimensional model of a tooth profile cavity of a gear precision injection mold, and dividing the three-dimensional model of the tooth profile cavity into a tooth top space region and a tooth surface space region; The corresponding gear center axis is taken as The coordinate system is established by the axis, and the tooth top space area and tooth surface space area are determined according to the geometric information of the tooth profile cavity, including: ； in, represents the tooth top space area, represents the tooth surface space area, represents three-dimensional coordinates, represents the radius of the tooth tip circle, Indicates the thickness of the tooth profile cavity, Indicates the tooth root circle radius; Setting a first ultrasonic phased array detection parameter and a second ultrasonic phased array detection parameter for the tooth top space area and the tooth surface space area; Performing ultrasonic phased array data acquisition on the tooth-shaped cavity of the gear precision injection mold according to the first ultrasonic phased array detection parameter and the second ultrasonic phased array detection parameter to obtain first overall ultrasonic phased array data and second overall ultrasonic phased array data; Preprocessing the first overall ultrasonic phased array data and the second overall ultrasonic phased array data; extracting tooth top ultrasonic phased array data and tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and the second overall ultrasonic phased array data according to the coordinate boundaries of the tooth top space region and the tooth surface space region; Extracting the tooth top ultrasonic phased array data from the first overall ultrasonic phased array data is expressed as: ； in, represents the tooth top ultrasonic phased array data, represents the first overall ultrasonic phased array data, represents the tooth addendum space region mask function, represents the tooth top space area; Extracting the tooth surface ultrasonic phased array data from the second overall ultrasonic phased array data is expressed as: ； in, represents the tooth surface ultrasonic phased array data, represents the second overall ultrasonic phased array data, represents the tooth surface spatial region mask function, Represents the tooth surface space area; Constructing a tooth top region feature vector extraction strategy and a tooth surface region feature vector extraction strategy, and extracting a tooth top region feature vector and a tooth surface region feature vector based on the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data; Defect detection is performed on the tooth profile cavity of the gear precision injection mold according to the tooth top area feature vector and the tooth surface area feature vector to obtain a defect influence degree index, and a processing decision is made according to the defect influence degree index.

2. A high-precision defect detection method for a gear precision injection mold according to claim 1, characterized in that: The detection parameters include step spacing, focused acoustic beam angle, focused acoustic beam depth and array element quantity.

3. The high-precision defect detection method for a gear precision injection mold according to claim 1 is characterized in that: The tooth top area feature vector extraction strategy includes: obtaining the amplitude of the echo signal in the tooth top space area to extract the echo intensity feature, obtaining the intensity change of the echo signal to extract the sound wave attenuation feature, obtaining the propagation time of the ultrasonic wave and calculating the sound speed, extracting the sound speed change feature, obtaining the echo signal intensity in different directions to calculate the scattering energy, extracting the scattering energy feature, and constructing the tooth top area feature vector according to the echo intensity feature, the sound wave attenuation feature, the sound speed change feature and the scattering energy feature; the tooth surface area feature vector extraction strategy includes: performing Fourier transform on the echo signal in the tooth surface space area, analyzing the energy distribution of different frequency components, extracting the spectrum energy feature, analyzing the scattering feature of the echo signal to calculate the scattering coefficient to extract the scattering coefficient feature, analyzing the distribution matrix of the signal strength at different angles to extract the multi-angle beam feature, analyzing the phase of the echo signal to calculate the phase offset to extract the phase offset feature, and constructing the tooth surface area feature vector according to the spectrum energy feature, the scattering coefficient feature, the multi-angle beam feature and the phase offset feature.

4. The high-precision defect detection method for a gear precision injection mold according to claim 1 is characterized in that: The defect detection of the tooth profile cavity of the gear precision injection mold according to the tooth top region feature vector and the tooth surface region feature vector comprises: Normalizing each eigenvalue in the tooth top region eigenvector and the tooth surface region eigenvector; Calculating a first defect influence index according to the standardized tooth top region feature vector; Calculating a second defect influence index according to the standardized tooth surface area feature vector; The first defect impact degree index and the second defect impact degree index are weighted and combined to obtain the defect impact degree index.

5. The high-precision defect detection method for a gear precision injection mold according to claim 1 is characterized in that: The processing decisions based on the defect impact index include: When the defect impact index is less than a first threshold, the tooth-shaped cavity of the gear precision injection mold is used and maintained according to a preset cycle; When the defect influence index is greater than or equal to the first threshold and less than or equal to the second threshold, increasing the regular inspection frequency of the tooth profile cavity of the gear precision injection mold; When the defect impact index is greater than the second threshold, targeted repairs are performed for repairable defects, and for unrepairable defects, the tooth profile cavity of the gear precision injection mold is replaced.

6. A high-precision defect detection system for gear precision injection molds, characterized in that: include: A region division module is used to obtain a three-dimensional model of a tooth profile cavity of a gear precision injection mold, and to divide the three-dimensional model of the tooth profile cavity into a tooth top space region and a tooth surface space region; The corresponding gear center axis is taken as The coordinate system is established by the axis, and the tooth top space area and tooth surface space area are determined according to the geometric information of the tooth profile cavity, including: ； in, represents the tooth top space area, represents the tooth surface space area, represents three-dimensional coordinates, represents the radius of the tooth tip circle, Indicates the thickness of the tooth profile cavity, Indicates the tooth root circle radius; a data acquisition module, setting a first ultrasonic phased array detection parameter and a second ultrasonic phased array detection parameter for the tooth top space area and the tooth surface space area; performing ultrasonic phased array data acquisition on the tooth profile cavity of the gear precision injection mold according to the first ultrasonic phased array detection parameter and the second ultrasonic phased array detection parameter, respectively, to obtain first overall ultrasonic phased array data and second overall ultrasonic phased array data; a regional data extraction module, preprocessing the first overall ultrasonic phased array data and the second overall ultrasonic phased array data; extracting tooth top ultrasonic phased array data and tooth surface ultrasonic phased array data from the preprocessed first overall ultrasonic phased array data and the second overall ultrasonic phased array data according to the coordinate boundaries of the tooth top space region and the tooth surface space region; Extracting the tooth top ultrasonic phased array data from the first overall ultrasonic phased array data is expressed as: ； in, represents the tooth top ultrasonic phased array data, represents the first overall ultrasonic phased array data, represents the tooth addendum space region mask function, represents the tooth top space area; Extracting the tooth surface ultrasonic phased array data from the second overall ultrasonic phased array data is expressed as: ； in, represents the tooth surface ultrasonic phased array data, represents the second overall ultrasonic phased array data, represents the tooth surface spatial region mask function, Represents the tooth surface space area; A regional feature extraction module is used to construct a tooth top regional feature vector extraction strategy and a tooth surface regional feature vector extraction strategy, and to extract a tooth top regional feature vector and a tooth surface regional feature vector based on the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data; The defect detection decision module performs defect detection on the tooth profile cavity of the gear precision injection mold according to the tooth top area feature vector and the tooth surface area feature vector, obtains a defect influence degree index, and makes a processing decision according to the defect influence degree index.

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