A high-precision defect detection method and system for gear precision injection molds

Abstract

The present invention relates to the field of gear mold detection technology, specifically to a high-precision defect detection method and system for a gear precision injection mold, comprising: dividing a tooth profile cavity into a tooth top space region and a tooth surface space region, setting a first ultrasonic phased array detection parameter and a second ultrasonic phased array detection parameter, respectively collecting ultrasonic phased array data for the tooth profile cavity, and obtaining 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 region feature vector extraction strategy and a tooth surface region feature vector extraction strategy, extracting tooth top region feature vectors and tooth surface region feature vectors, performing defect detection on the gear precision injection mold tooth profile cavity, and obtaining a defect influence degree index for processing and decision making. The present invention improves the accuracy of internal defect detection in gear injection molds.

Description

Technical Field

[0001] The present invention relates to the technical field of gear mould detection, and in particular to a high-precision defect detection method and system for a gear precision injection mould. 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. The precision injection mold for gears plays a vital role in the gear manufacturing process, and its quality determines the accuracy and quality of the gears produced.

[0003] At present, most of the research and application of gear injection mold inspection technology focuses on surface defect detection. For example, common visual inspection technology uses high-resolution cameras to collect mold surface images and uses image recognition algorithms to identify surface defects such as scratches, cracks, and wear. However, internal defects in injection molds cannot be ignored either, as they increase the risk of mold damage and have a significant impact on the production of injection molded parts.

[0004] Existing gear injection mold defect detection technology lacks an effective method for internal defect detection. Defects inside the mold, such as internal cracks, pores, and inclusions, are difficult to be discovered in a timely manner through existing surface detection methods. These internal defects will gradually expand under the action of stress during the long-term use of the mold, resulting in a decrease in the structural strength of the mold, and eventually causing the mold to fail prematurely, which not only increases production costs, but may also affect production progress and product quality. In addition, the tooth-shaped cavity of the precision injection mold of the gear often contains several internal grooves and tooth-shaped protrusions, which interfere with the propagation and reflection of the detection signal, and general ultrasonic testing or X-ray detection methods often do not perform comprehensive detection on the complex geometric shapes of the mold.

[0005] Therefore, a high-precision defect detection method and system for gear precision injection molds are proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a high-precision defect detection method and system for a precision injection mold for gears. By dividing the tooth-shaped cavity into a tooth top space region and a tooth surface space region, setting a first ultrasonic phased array detection parameter and a second ultrasonic phased array detection parameter, ultrasonic phased array data acquisition is performed on the tooth-shaped cavity respectively to obtain first overall ultrasonic phased array data and second overall ultrasonic phased array data; tooth top ultrasonic phased array data and tooth surface ultrasonic phased array data are extracted from the preprocessed first overall ultrasonic phased array data and second overall ultrasonic phased array data, and a tooth top region feature vector extraction strategy and a tooth surface region feature vector extraction strategy are constructed to extract the tooth top region feature vector and the tooth surface region feature vector, perform defect detection on the tooth-shaped cavity of the precision injection mold for gears, and obtain a defect influence degree index for processing and decision making. The present invention improves the accuracy of internal defect detection in gear injection molds.

[0007] To achieve the above object, the present invention provides the following technical solutions: A high-precision defect detection method for a gear precision injection mold, comprising: 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; 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; 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.

[0008] Further, the three-dimensional model of the tooth profile cavity is obtained, and the corresponding gear center axis is used as The coordinate system is established by the axis, and the tooth top space area and the 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 root circle radius.

[0009] Furthermore, the detection parameters include step spacing, focused acoustic beam angle, focused acoustic beam depth and number of array elements.

[0010] Further, extracting the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data includes: 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.

[0011] Furthermore, 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.

[0012] Further, performing defect detection on 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.

[0013] Further, making a processing decision according to the defect impact index includes: 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.

[0014] A high-precision defect detection system for a gear precision injection mold, comprising: 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; 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; 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.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 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.

[0016] 2. The feature vector extraction strategies for the tooth top area and the tooth surface area are constructed respectively. This dual feature vector extraction strategy fully considers the differences in the physical properties of the two areas. Through different feature extraction methods, it can capture defect information more comprehensively and improve the ability to identify irregular defects. By extracting multi-dimensional features, it can ensure the comprehensiveness and accuracy of detection. The coordinated use of the two feature vector extraction strategies not only ensures the comprehensiveness of the detection, but also ensures the targeted detection of each area. Through the differentiated feature extraction strategy, the accurate identification of internal defect features in different spatial regions is achieved, especially when facing complex mold shapes and diversified defects, the potential information in the ultrasonic data can be fully mined.

[0017] 3. A hierarchical processing decision mechanism based on the defect impact index is set up. First, the feature vectors of the tooth top area and the tooth surface area are standardized, and the first defect impact index and the second defect impact index are calculated respectively. The final defect impact index is obtained by weighted merging, and the hierarchical processing decision is set in combination with the threshold. This grading mechanism not only provides a quantitative evaluation standard for the internal defect degree of the gear mold tooth profile cavity, but also is directly related to the actual maintenance decision, providing a scientific basis for the maintenance and replacement of the mold, realizing the precise management of the internal defect situation of the tooth profile cavity, and improving production efficiency and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic flow chart of a method for high-precision defect detection of a gear precision injection mold of the present invention; Figure 2 It is a schematic diagram of the tooth-shaped cavity structure of the gear precision injection mold of the present invention; Figure 3 The present invention is a schematic diagram of the structure of a high-precision defect detection system for a gear precision injection mold.

[0019] In the figure: 1. Tooth profile cavity; 2. Tooth top circle; 3. Tooth root circle; 4. Center of circle; 5. Tooth top space area; 6. Tooth surface space area. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] See also Figures 1 to 3 The present invention provides a high-precision defect detection method and system for a gear precision injection mold, and the technical solution is as follows: Embodiment 1:

[0022] A high-precision defect detection method for a gear precision injection mold, the method flow is as follows Figure 1 As shown, including: 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; 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; 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.

[0023] Further, the three-dimensional model of the tooth profile cavity is obtained, and the corresponding gear center axis is used as The coordinate system is established by the axis, and the tooth top space area and the 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 root circle radius.

[0024] like Figure 2As shown, a structural example diagram of a tooth profile cavity 1 is given, the center 4 of the tooth top circle 2 and the tooth root circle 3 is located on the central axis of the gear, and the figure shows the tooth top space area 5 and the tooth surface space area 6 in a sector area. In the entire tooth profile cavity 1, the tooth top space area 5 is the disc-shaped area between the outer ring of the tooth profile cavity 1 and the tooth top circle 2, and the tooth surface space area 6 is the sawtooth area between the tooth top circle 2 and the tooth root circle 3.

[0025] The tooth top space area and tooth surface space area are determined based on the geometric information of the tooth profile cavity, which effectively improves the localization and pertinence of defect detection, can better detect potential defects in the complex structure of the mold, and improve the accuracy and reliability of the detection results.

[0026] Furthermore, the detection parameters include step spacing, focused acoustic beam angle, focused acoustic beam depth and number of array elements.

[0027] This embodiment is aimed at defect detection of a plastic gear injection mold for a certain automobile gearbox. The mold is made of P20 mold steel, and the mold cavity is a spur gear structure with a cavity diameter of 98mm, a tooth top circle diameter of 78mm, a tooth root circle diameter of 66mm, and a tooth cavity thickness of 25mm. During the production process, it was found that the injection molded parts had local dimensional deviations, and the mold needed to be non-destructively tested 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.

[0028] Table 1 Detection parameter settings

[0029] By setting the step spacing, focused beam angle, focused beam depth and number of array elements, the internal information of the mold can be obtained more accurately, the detection details can be improved, smaller defects can be detected, and the quality and reliability of the data can be improved.

[0030] Further, extracting the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data includes: 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.

[0031] By extracting ultrasonic phased array data from the tooth top and tooth surface spatial areas, the defects in each area can be analyzed independently, avoiding data interference between areas. For gear molds with complex structures, the accuracy of subsequent feature extraction is guaranteed, providing a reliable data basis for defect detection and enabling detailed inspections in various key areas.

[0032] Furthermore, 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.

[0033] The feature vector extraction strategies are constructed for the tooth top and tooth surface space areas respectively, which can comprehensively analyze the state of the mold from different angles, improve the comprehensiveness and accuracy of defect detection, and effectively detect the inherent defects that are not easy to detect. Through different types of signal analysis and feature vector construction, the complex ultrasonic echo signal can be converted into an easy-to-understand feature vector, which enhances the quantitative analysis capability of mold defects.

[0034] Further, performing defect detection on 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.

[0035] The calculation of the first defect impact index and the second defect impact index includes: calculating the relative deviation between each characteristic component and the corresponding abnormal threshold, and performing weighted summation of the relative deviation and the impact weight to obtain the first defect impact index and the second defect impact index. The calculation of the relative deviation includes: when the first Feature Components Greater than the corresponding abnormal threshold When the relative deviation ; When the Feature Components Less than or equal to the corresponding abnormal threshold When the relative deviation .

[0036] Table 2 shows the normalized results of the feature vectors in the tooth top region and the tooth surface region and the abnormal threshold corresponding to each feature component.

[0037] Table 2. Results of regional feature vector normalization

[0038] The defect impact index is established by standardizing the feature values ​​and weighted merging, which not only takes into account the dimensional differences of different features, but also balances the importance of each feature. By calculating the defect impact index, an objective defect assessment basis can be provided.

[0039] Further, making a processing decision according to the defect impact index includes: 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.

[0040] A threshold-based multi-level processing decision-making mechanism has been established, which can provide accurate maintenance and replacement decisions, avoid excessive maintenance, and promptly detect and deal with serious defects, ensuring that timely measures can be taken when potential risks arise in the mold, thereby improving the efficiency of mold management and reducing risks, optimizing mold maintenance strategies, and improving economic benefits.

[0041] The present invention divides the three-dimensional model of the tooth profile cavity into a tooth top space region and a tooth surface space region, and adopts differentiated ultrasonic phased array detection parameters for data collection in different regions, which not only improves the pertinence of the detection, but also can adapt to the complex geometric structure characteristics of the tooth profile cavity. 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. The defect influence index is calculated based on the extracted feature vector, and a scientific hierarchical decision-making mechanism is established, which can timely discover internal defects and take corresponding maintenance measures. The present invention overcomes the problem of insufficient accuracy in detecting internal defects of gear injection molds, realizes high-precision detection of internal defects of tooth profile cavities, improves the accuracy and reliability of detection, and provides a scientific basis for preventive maintenance of molds.

[0042] Embodiment 2: This embodiment further provides a high-precision defect detection system for a gear precision injection mold, the system structure is as follows: Figure 3 As shown, including: 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; 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; 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.

[0043] Further, the three-dimensional model of the tooth profile cavity is obtained, and the corresponding gear center axis is used as The coordinate system is established by the axis, and the tooth top space area and the 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 root circle radius.

[0044] Furthermore, the detection parameters include step spacing, focused acoustic beam angle, focused acoustic beam depth and number of array elements.

[0045] Further, extracting the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data includes: 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.

[0046] Furthermore, 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.

[0047] Further, performing defect detection on 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.

[0048] Further, making a processing decision according to the defect impact index includes: 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.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that 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; 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; 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: Obtain the three-dimensional model of the tooth profile cavity, and use the corresponding gear center axis as The coordinate system is established by the axis, and the tooth top space area and the 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 root circle radius.

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

4. The high-precision defect detection method for a gear precision injection mold according to claim 1 is characterized in that: Extracting the tooth top ultrasonic phased array data and the tooth surface ultrasonic phased array data includes: 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.

5. 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.

6. 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.

7. 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.

8. 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; 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; 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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