Method and system for analyzing sintering degree of metal powder based on ultrasonic vibration assistance

Abstract

The application discloses a metal powder sintering degree analysis method and system based on ultrasonic vibration assistance, and belongs to the technical field of material detection. The method comprises the following steps: obtaining initial vibration parameters and initial process parameters for defining initial sintering conditions, and generating initial control parameters; applying ultrasonic vibration to the metal powder based on the initial control parameters, and obtaining real-time echo signals in the sintering process to generate ultrasonic detection signals; analyzing the ultrasonic detection signals to generate sintering degree evaluation parameters; adjusting the initial control parameters based on the sintering degree evaluation parameters to generate updated control parameters; and using the updated control parameters to perform feedback control on subsequent ultrasonic vibration application and sintering processes. The application adopts ultrasonic vibration excitation and real-time echo signal monitoring, and combines real-time signal processing, so that real-time and nondestructive evaluation of the sintering degree of the metal powder can be realized, and the precision and efficiency of the sintering process are improved.

Description

Technical Field

[0001] This invention relates to the field of materials testing technology, and in particular to a method and system for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance. Background Technology

[0002] Powder metallurgy is an advanced metal material preparation technology, with sintering as its core process. Sintering involves heat-treating metal powder compacts at temperatures below the material's melting point. Through physicochemical processes such as atomic migration, powder particles are bonded together, porosity is reduced, and a dense solid with desired properties is ultimately formed. Ultrasonic vibration-assisted sintering, as a strengthening technique, introduces high-frequency mechanical vibration to promote powder particle rearrangement and mass transfer. Therefore, real-time and accurate analysis of the densification degree during sintering is crucial for controlling the quality and performance of the final product.

[0003] Currently, the analysis of the sintering degree of metal powders mainly relies on offline post-processing detection methods. Typically, after the sintering process is completely finished, the sample is removed, and its density is measured using the Archimedes method, or its porosity and grain size are observed using a metallographic microscope, or mechanical property tests are performed to evaluate the sintering quality. During the sintering process, some online monitoring technologies mainly measure the macroscopic dimensional changes of the sample, such as using a thermal dilatometer, or simply monitor external process parameters such as the temperature and pressure of the sintering furnace. For the control of ultrasonic vibration-assisted sintering, an open-loop control method is usually adopted, that is, a fixed sintering temperature curve and ultrasonic vibration parameters are pre-set based on experience or models and remain constant throughout the process.

[0004] Existing sintering degree analysis methods have shortcomings. Offline post-processing detection methods are lagging and cannot provide any feedback information for real-time process adjustments during sintering; once quality problems occur, they are irreversible. Existing online monitoring methods, such as thermal expansion measurement, only reflect changes in the macroscopic dimensions of the sample; their relationship with the densification degree of the internal microstructure is not a simple linear one, resulting in limited analytical accuracy. Open-loop control relies entirely on process parameters and cannot adapt to batch variations in raw material properties or uneven temperature fields within the furnace, making it difficult to guarantee the consistency of sintered product quality. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a method and system for analyzing the degree of sintering of metal powder based on ultrasonic vibration. By employing ultrasonic vibration excitation and real-time monitoring of echo signals, combined with real-time signal processing, it is possible to achieve real-time, non-destructive evaluation of the degree of sintering of metal powder, thereby improving the accuracy and efficiency of the sintering process.

[0006] The above objectives can be achieved through the following approach:

[0007] A method and system for analyzing the degree of sintering of metal powder based on ultrasonic vibration includes: acquiring initial vibration parameters and initial process parameters to define the initial sintering conditions, and generating initial control parameters; applying ultrasonic vibration to the metal powder based on the initial control parameters, and acquiring real-time echo signals during the sintering process to generate ultrasonic detection signals; analyzing the ultrasonic detection signals to generate sintering degree evaluation parameters; adjusting the initial control parameters based on the sintering degree evaluation parameters to generate updated control parameters; and using the updated control parameters to provide feedback control for subsequent ultrasonic vibration application and sintering processes.

[0008] Optionally, the step of analyzing the ultrasonic detection signal to generate sintering degree evaluation parameters includes: extracting sound velocity features and attenuation features from the ultrasonic detection signal to generate signal feature parameters; calculating the density and porosity of the sintered metal powder body based on the signal feature parameters to generate physical state parameters; and fusing the physical state parameters to generate sintering degree evaluation parameters.

[0009] Optionally, adjusting the initial control parameters to generate updated control parameters based on the sintering degree evaluation parameters includes: obtaining target sintering parameters for defining an ideal sintering process, comparing them with the sintering degree evaluation parameters to generate deviation parameters; generating adjustment parameters based on the deviation parameters; and generating updated control parameters by combining the adjustment parameters with the current control state.

[0010] Optionally, acquiring the real-time echo signal and generating the ultrasonic detection signal includes: emitting ultrasonic pulses to the metal powder and receiving the echoes to generate raw detection data; performing bandpass filtering on the raw detection data to generate a filtered signal; and amplifying and digitizing the filtered signal to generate the ultrasonic detection signal.

[0011] Optionally, obtaining the initial vibration parameters and initial process parameters used to define the initial sintering conditions and generating the initial control parameters includes: obtaining the material property parameters of the metal powder to be sintered; obtaining the initial vibration parameters and initial process parameters based on the material property parameters; and combining the initial vibration parameters and the initial process parameters to generate the initial control parameters.

[0012] Optionally, the method further includes: generating sintering control instructions based on the updated control parameters; executing the sintering control instructions to bring the sintering process into an optimized sintering state; monitoring the optimized sintering state and recording its correspondence with the updated control parameters, and updating the knowledge system used to generate the initial control parameters.

[0013] Optionally, the step of calculating the density and porosity of the sintered metal powder body based on the signal feature parameters and generating physical state parameters includes: converting the signal feature parameters into preliminary evaluation data; acquiring the real-time sintering temperature and performing error correction on the preliminary evaluation data to generate corrected data; acquiring historical sintering data and fusing it with the corrected data to generate physical state parameters.

[0014] Optionally, generating adjustment parameters based on the deviation parameters includes: fuzzifying the deviation parameters to generate fuzzy input variables; performing inference on the fuzzy input variables to generate fuzzy control outputs; comparing the fuzzy control outputs with preset safe operating range constraints and performing defuzzification to generate adjustment parameters.

[0015] Optionally, the step of emitting ultrasonic pulses to the metal powder and receiving echoes to generate raw detection data includes: emitting ultrasonic pulses to the metal powder and performing a linear scan of the metal powder, receiving echo signals from the powder particle boundaries and internal defects; and acquiring the amplitude and time-of-flight information of the echo signals to generate raw detection data.

[0016] Based on the same inventive concept, this invention also provides a metal powder sintering degree analysis system based on ultrasonic vibration assistance. The system includes: a parameter acquisition module for acquiring initial vibration parameters and initial process parameters to define initial sintering conditions and generating initial control parameters; an ultrasonic signal generation module for applying ultrasonic vibration to the metal powder based on the initial control parameters and acquiring real-time echo signals during the sintering process to generate ultrasonic detection signals; a signal analysis and evaluation module for analyzing the ultrasonic detection signals and generating sintering degree evaluation parameters; a new control parameter generation module for adjusting the initial control parameters based on the sintering degree evaluation parameters to generate updated control parameters; and a control execution module for using the updated control parameters to perform feedback control on the subsequent application of ultrasonic vibration and the sintering process.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] This invention constructs a closed-loop feedback control system, which can monitor the state deviation during the sintering process in real time and adjust the control parameters immediately. It actively suppresses process deviations caused by uncertainties such as raw material fluctuations or environmental interference, thereby improving the stability and repeatability of the sintering process.

[0019] This invention proposes a high-precision quantitative evaluation method. By extracting multi-dimensional ultrasonic features such as sound velocity and attenuation, and combining temperature correction with historical data fusion, the abstract acoustic signal is transformed into intuitive physical state parameters such as density and porosity. This achieves a leap from qualitative observation to precise quantitative analysis of the degree of sintering, ensuring the accuracy of the evaluation results.

[0020] This invention establishes an intelligent process system with self-learning and optimization capabilities. By recording and analyzing successful control processes, it can continuously update its internal knowledge model, enabling the system to have better initial parameter setting capabilities when handling new sintering tasks, reducing reliance on human experience and shortening the process development cycle.

[0021] This invention utilizes ultrasound as the detection medium to achieve online, non-destructive monitoring of the evolution of the internal microstructure of metal powder. This allows quality control to be carried out during the sintering process, rather than being limited to post-processing inspection. It provides the possibility of preventing and promptly correcting quality defects, ensuring the performance and reliability of the final product.

[0022] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic flowchart of the ultrasonic vibration-assisted metal powder sintering degree analysis method according to an embodiment of the present invention.

[0025] Figure 2 This is a linear scan and echo signal diagram of metal powder according to an embodiment of the present invention.

[0026] Figure 3 This is a graph showing the change in ultrasonic velocity during the sintering process according to an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of the ultrasonic vibration-assisted metal powder sintering degree analysis system according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Reference Figure 1 One embodiment of the present invention proposes a method for analyzing the degree of sintering of metal powder based on ultrasonic vibration. By using ultrasonic vibration excitation and real-time monitoring of echo signals, combined with real-time signal processing, it is possible to achieve real-time, non-destructive evaluation of the degree of sintering of metal powder, thereby improving the accuracy and efficiency of the sintering process.

[0030] The method described in this embodiment specifically includes:

[0031] S1. Obtain the initial vibration parameters and initial process parameters used to define the initial sintering conditions, and generate the initial control parameters;

[0032] Optionally, obtaining the initial vibration parameters and initial process parameters used to define the initial sintering conditions, and generating the initial control parameters, includes:

[0033] Obtain the material property parameters of the metal powder to be sintered;

[0034] Based on the aforementioned material property parameters, the initial vibration parameters and initial process parameters are obtained;

[0035] The initial vibration parameters and the initial process parameters are combined to generate the initial control parameters.

[0036] Specifically, the first step is to obtain the material property parameters of the metal powder to be sintered. These parameters include the inherent physical properties of the metal powder, such as chemical composition, average particle size, initial compact density, and theoretical sintering temperature. These parameters are typically obtained from data provided by the supplier or through pre-conducted experimental measurements, and they are the fundamental basis for determining the initial sintering conditions. Next, based on the material property parameters, a pre-established knowledge system or empirical model is consulted to obtain the initial vibration parameters and initial process parameters. For example, metal powders with higher melting points require higher sintering temperatures and different vibration frequencies; this correlation is provided by the knowledge system. The initial vibration parameters define the initial characteristics of the ultrasonic waves applied to the powder, such as frequency. and amplitude The initial process parameters define the initial thermal parameters of the sintering furnace, such as the initial heating rate. and initial insulation temperature Finally, the initial vibration parameters and initial process parameters are combined to generate the initial control parameters. The assembly process involves logically integrating all predetermined initial settings to form a complete instruction set that can be directly input into the sintering equipment. It can be represented as the set of all initial parameters, that is:

[0037] },

[0038] in, These are the initial control parameters, which are a set of instructions; It is the initial ultrasonic frequency in the initial vibration parameters, which is obtained by consulting the knowledge system of material properties and vibration parameters; It is the initial ultrasonic amplitude in the initial vibration parameters, which is obtained by consulting the knowledge system of material properties and vibration parameters; It is the initial heating rate in the initial process parameters, which is obtained by consulting the knowledge system of material properties and process parameters; It is the initial insulation temperature in the initial process parameters, which is obtained by consulting the knowledge system of material properties and process parameters.

[0039] For example, suppose the metal powder to be sintered is a nickel-based superalloy powder with high density requirements. The system first obtains its material property parameters, including an average particle size of 10 micrometers and a theoretical melting point of 1450 degrees Celsius. Based on these material property parameters, the system consults a knowledge system for nickel-based alloys and determines that relatively high vibration energy and a moderate heating rate are required. The knowledge system gives the initial vibration parameters as an ultrasonic frequency of 20 kHz and an amplitude of 4 micrometers; it also gives the initial process parameters as an initial heating rate of 12 degrees Celsius per minute and a maximum sintering temperature of 1350 degrees Celsius. These initial vibration parameters and initial process parameters are then logically combined into an initial control parameter, such as a command file containing all set values, to guide the sintering equipment to start and execute the first sintering stage.

[0040] S2. Apply ultrasonic vibration to the metal powder based on the initial control parameters, and acquire real-time echo signals during the sintering process to generate ultrasonic detection signals;

[0041] Optionally, acquiring the real-time echo signal and generating the ultrasonic detection signal includes:

[0042] Ultrasonic pulses are emitted toward metal powder and the echoes are received to generate raw detection data.

[0043] The original detection data is subjected to bandpass filtering to generate a filtered signal;

[0044] The filtered signal is amplified and digitally converted to generate an ultrasonic detection signal.

[0045] Specifically, the process begins with applying ultrasonic vibration and sintering to the metal powder based on the initial control parameters. These initial control parameters are a set of preset instructions determined by the system before sintering begins. They are used to start the sintering equipment and ultrasonic generator, determining the initial sintering temperature, heating rate, and the frequency and amplitude of the ultrasonic waves. While the sintering process continues, real-time echo signals are acquired to generate ultrasonic detection signals. The specific operation includes the following three detailed steps: First, ultrasonic pulses are emitted to the metal powder and echoes are received to generate raw detection data. This requires using an ultrasonic probe to apply ultrasonic excitation to the sintering metal powder. The probe emits brief but powerful ultrasonic pulses at a specific pulse repetition frequency. The sound waves propagate within the metal powder and are reflected due to structural discontinuities such as particle interfaces and pores, forming echo signals. A high-speed data acquisition system synchronously receives these echo signals, records their amplitude and time information, and generates raw detection data. Second, the raw detection data undergoes bandpass filtering to generate a filtered signal. Since the acquired signals typically contain high-frequency electrical noise and low-frequency mechanical vibration noise, digital or analog bandpass filters are needed to selectively retain the signal frequency band that matches the center frequency of the ultrasonic pulse, effectively removing irrelevant noise to obtain a clean filtered signal. The third step involves amplifying and digitizing the filtered signal to generate an ultrasonic detection signal. The amplitude of the filtered signal may be relatively weak, requiring appropriate gain through a signal amplifier to improve the signal-to-noise ratio and measurement accuracy. Subsequently, the amplified analog signal is digitized at a high sampling rate using an analog-to-digital converter, converting it into a discrete digital sequence, which is the final ultrasonic detection signal.

[0046] For example, taking sintered tungsten powder as an example, the system first sets the sintering furnace temperature to 1500 degrees Celsius, the ultrasonic generator frequency to 25 kHz, and the amplitude to 3 micrometers according to the initial control parameters. During the sintering and holding stage, the ultrasonic probe starts working, emitting ultrasonic pulses at a center frequency of 5 MHz to the tungsten powder compact, and receiving the echo signals reflected from within it, recording them as raw detection data. To eliminate noise generated by the high-temperature environment and electromagnetic interference, the raw detection data is passed through a bandpass filter, retaining only the signal components in the range of 4.5 MHz to 5.5 MHz, forming a filtered signal. Then, the amplitude of this filtered signal is amplified by an amplifier with a gain of 40 dB, and then converted into a digital sequence by a high-speed analog-to-digital converter at a sampling rate of 100 MHz, thus generating the ultrasonic detection signal used for subsequent sintering degree analysis.

[0047] Optionally, the step of emitting ultrasonic pulses to the metal powder and receiving the echoes to generate raw detection data includes:

[0048] An ultrasonic pulse is emitted to the metal powder and a linear scan is performed on the metal powder to receive echo signals from the powder particle boundaries and internal defects.

[0049] The amplitude and time-of-flight information of the echo signal are collected to generate raw detection data.

[0050] Specifically, linear scanning of metal powder and echo signals, such as Figure 2 As shown, the process begins with emitting ultrasonic pulses into the metal powder and performing a linear scan to receive the echo signals. Linear scanning is a systematic non-destructive testing method that uses a moving ultrasonic probe or a probe array to sequentially excite and receive ultrasonic signals located at different spatial positions, ensuring comprehensive coverage and monitoring of the evolution of the internal structure of the sintered metal powder. The ultrasonic pulses are generated by the probe and transmitted into the sintering metal powder. When the sound waves encounter the boundaries of powder particles, unsintered contact points, and internal defects including pores and inclusions, reflection and scattering occur, forming echo signals. These reflected echo signals are continuously received. Subsequently, data acquisition is performed on the echo signals to obtain their amplitude and time-of-flight information, ultimately generating raw test data. Amplitude refers to the peak voltage or sound pressure level of the echo signal, quantifying the energy attenuation of the ultrasonic wave during propagation, and is measured in real-time by a high-speed data acquisition card. Time-of-flight information refers to the time interval required from the emission of the ultrasonic pulse to the reception of a specific echo; it is closely related to the propagation distance and speed of sound in the medium and is measured by a high-precision timer within the acquisition card. These two parameters together constitute the raw detection data captured at each linear scan location.

[0051] For example, during the detection of copper powder in sintering, an ultrasonic pulse with a center frequency of 5 MHz is emitted into the sintered copper powder. An ultrasonic probe mounted on a motion mechanism linearly scans the surface of the copper powder along a preset path, continuously transmitting and receiving echo signals at a frequency of 10 times per second. During the scan, the system immediately acquires the amplitude and time-of-flight information for each received echo signal; for example, recording an echo amplitude of 0.8 volts and a time-of-flight information of 5 microseconds. By continuously recording these amplitude, time, and time-of-flight information data pairs along the entire linear scan path, a raw detection dataset containing all scan points is finally generated for subsequent bandpass filtering and digitization.

[0052] S3. Analyze the ultrasonic detection signal to generate sintering degree evaluation parameters;

[0053] Optionally, the analysis of the ultrasonic detection signal to generate sintering degree evaluation parameters includes:

[0054] Sound velocity and attenuation features are extracted from the ultrasonic detection signal to generate signal feature parameters;

[0055] The density and porosity of the sintered metal powder body are calculated based on the signal characteristic parameters to generate physical state parameters.

[0056] The physical state parameters are fused to generate sintering degree evaluation parameters.

[0057] Specifically, the first step is to extract key feature information from the acquired ultrasonic detection signal, including sound velocity and attenuation characteristics. Sound velocity is determined by measuring the time required for the ultrasonic wave to pass through the metal powder medium and combining this with the known propagation distance. Attenuation is quantified by analyzing the energy loss of the ultrasonic signal during propagation, typically manifested as a decrease in echo amplitude. These two characteristics together constitute the signal characteristic parameters. Next, based on the acquired signal characteristic parameters, the density and porosity of the material are calculated using the intrinsic correlation between acoustic properties and the material's physical state. Density and porosity are two core physical quantities characterizing the degree of densification during sintering. By establishing a correlation model between sound velocity, attenuation, and density and porosity, the current physical state parameters can be deduced from the signal characteristic parameters. The change in ultrasonic sound velocity during the sintering process is shown in the figure. Figure 3 As shown. Finally, to obtain a single index that comprehensively reflects the sintering process, the physical state parameters, namely the calculated density and porosity, need to be fused. This fusion can be a weighted algorithm or a more complex function that integrates two independent physical quantities into a comprehensive sintering degree assessment parameter.

[0058] For example, a batch of copper powder is undergoing ultrasonic vibration-assisted sintering. The system continuously acquires real-time echo signals during the sintering process, generating ultrasonic detection signals. The analysis module receives the ultrasonic detection signal at a specific moment, calculates the echo's flight time and amplitude changes, and extracts the current sound velocity as 4000 meters per second and the attenuation as 3 dB per centimeter. These two values ​​constitute the signal characteristic parameters at that moment. Subsequently, the system calls a pre-established copper powder sintering model, which correlates the signal characteristic parameters with the material's physical state. Based on the input sound velocity of 4000 meters per second and attenuation of 3 dB per centimeter, the model calculates that the material's current density is 92% of the theoretical density and its porosity is 8%. These two values ​​together constitute the physical state parameters. Finally, to facilitate control system decision-making, the fusion module is activated. It may use a preset evaluation function, such as a weighted combination of density and porosity, to generate a comprehensive score between 0 and 1. The system ultimately outputs a sintering degree evaluation parameter with a value of 0.9, which will be used to compare with the target sintering parameters to adjust and control the sintering process.

[0059] Optionally, the step of calculating the density and porosity of the sintered metal powder body based on the signal characteristic parameters to generate physical state parameters includes:

[0060] The signal characteristic parameters are converted into preliminary evaluation data;

[0061] The real-time sintering temperature is obtained, and the preliminary evaluation data is corrected for errors to generate corrected data.

[0062] Historical sintering data is acquired and fused with the corrected data to generate physical state parameters.

[0063] Specifically, the obtained signal characteristic parameters are first converted into preliminary evaluation data. This conversion is based on the material's fundamental acoustic model at room temperature, for example, by mapping the sound velocity and attenuation values ​​to preliminary density and porosity estimates through simple functional relationships or table lookups. Next, the real-time sintering temperature is obtained. Since the acoustic properties of the material change with increasing temperature, this real-time temperature value is used to correct errors in the preliminary evaluation data. The correction process applies a pre-established temperature-sound velocity attenuation correction model. This model describes the attenuation at different temperatures... Changes in sound velocity or decay relative to standard temperature or Corrected density or porosity It can be obtained through the following relationship:

[0064] ,

[0065] ,

[0066] in, This is the corrected density. These are density estimates from the preliminary assessment data. Based on real-time temperature Caused change in sound speed The correction function for density, This is the inherent theoretical density of the metallic material to be sintered. Finally, historical sintering data is acquired and fused with the corrected data to generate physical state parameters. Historical sintering data includes the acoustic characteristics of the same or similar materials under different sintering conditions, and the correspondence between temperature and final density and porosity. The fusion process can employ methods such as Kalman filtering, weighted averaging, or machine learning models to integrate the corrected data obtained from real-time monitoring. Compared with known historical trend data Combination:

[0067] ,

[0068] in, It is the fused data, that is, the final physical state parameters. This is the corrected data. It is historical sintering data. and These are weighting coefficients, and they satisfy... The purpose of fusion is to leverage the stability and reliability of historical data to smooth out noise in real-time data, while ensuring that physical state parameters accurately reflect the current sintering state.

[0069] For example, the system extracts the signal characteristic parameters at a certain moment from the ultrasonic detection signal as a sound velocity of 4500 m / s and an attenuation of 2 dB per centimeter. Based on the initial model, this is converted into preliminary evaluation data, estimating the density to be 85% of the theoretical density. Subsequently, the thermocouple monitors the current sintering temperature in real time as 1000 degrees Celsius. The system consults the temperature correction model and finds that at 1000 degrees Celsius, the material's sound velocity will decrease by 50 m / s due to factors such as thermal expansion, which corresponds to a -1% deviation in the density estimation. The system applies this correction, correcting the preliminary evaluation data to a corrected data of 85% + 1% = 86%. Finally, the system retrieves historical sintering data from the database, showing that at the current temperature and sintering time, the average density of similar materials should be 87%. The system weights and fuses the real-time corrected 86% with the historical data's 87%, for example, with weights of 0.7 and 0.3, ultimately generating the physical state parameters, i.e., the density. The fused density value, along with the calculated porosity, is output as the final physical state parameter.

[0070] S4. Based on the sintering degree evaluation parameters, adjust the initial control parameters to generate updated control parameters;

[0071] Optionally, adjusting the initial control parameters to generate updated control parameters based on the sintering degree evaluation parameters includes:

[0072] Obtain the target sintering parameters used to define the ideal sintering process, and compare them with the sintering degree evaluation parameters to generate deviation parameters;

[0073] Based on the deviation parameters, adjustment parameters are generated;

[0074] Based on the adjustment parameters and the current control state, updated control parameters are generated.

[0075] Specifically, the first step is to obtain the target sintering parameters used to define the ideal sintering process. These target sintering parameters are pre-set and represent the ideal physical state that the metal powder should reach at a specific time point or stage. Then, the real-time acquired sintering degree evaluation parameters are compared with these target sintering parameters, and the difference between the two is calculated to generate a deviation parameter. This step can be represented as follows:

[0076] ,

[0077] in, It is a deviation parameter. These are the target sintering parameters obtained. These are sintering degree evaluation parameters derived from the previous analysis. and They have the same dimensions, such as density values ​​or comprehensive evaluation scores. Next, based on the generated deviation parameters, an adjustment parameter is generated using a specific control algorithm. This adjustment parameter quantifies the magnitude of correction needed for the current sintering conditions. Finally, this adjustment parameter is combined with the current control state to generate updated control parameters. The current control state refers to the parameter values ​​upon which the sintering equipment is currently operating; these are the initial control parameters during the first cycle. The combination process can be expressed as:

[0078] ,

[0079] in, These are the generated update control parameters. This refers to the current control state, such as the current vibration frequency or sintering temperature. These are adjustment parameters generated based on the deviation parameters.

[0080] For example, at a certain sintering stage, the system obtains a target sintering parameter of 90% of the theoretical density. However, the real-time sintering degree assessment parameter obtained through ultrasonic detection and analysis shows that the current density is only 88%. The system compares these two parameters and generates a deviation parameter of +2%. After receiving this deviation parameter, the control system processes it based on control rules and determines that the energy of the ultrasonic vibration needs to be increased to accelerate densification. Therefore, it generates an adjustment parameter, which corresponds to an increase of 3 micrometers in the ultrasonic amplitude. At this time, the system reads the current control status, showing that the current ultrasonic amplitude setting is 20 micrometers. The system then combines this adjustment parameter with the current control status to generate an updated control parameter, namely a new amplitude setting of 23 micrometers. This updated control parameter will be immediately used in subsequent sintering processes to bring the sintering state closer to the target value.

[0081] Optionally, generating adjustment parameters based on the deviation parameters includes:

[0082] The deviation parameter is fuzzified to generate fuzzy input variables;

[0083] Inference is performed on the fuzzy input variables to generate fuzzy control output;

[0084] The fuzzy control output is compared with the preset safe operating range constraints, and defuzzification is performed to generate adjustment parameters.

[0085] Specifically, firstly, the deviation parameters obtained by comparing the sintering degree evaluation parameters with the target sintering parameters are analyzed. Fuzzification is performed to generate fuzzy input variables. Fuzzification is the process of converting precise numerical inputs... The process of converting the input variables into fuzzy linguistic variables, such as transforming "+2% deviation" into fuzzy sets like "positive" or "neutral," is achieved through membership functions. Next, inference is performed on the fuzzy input variables to generate fuzzy control outputs. This inference process is the core of the fuzzy controller. Based on a pre-established fuzzy rule base, such as "if the deviation is positive and the rate of change is zero, then the control quantity should be negative," it uses fuzzy logic operations, such as minimum value operations and maximum value synthesis, to derive fuzzy suggestions for correcting the control quantity. Subsequently, the fuzzy control output is compared with safe operating range constraints. These constraints are hard limits set in engineering to prevent damage to sintering equipment or products due to excessive parameter adjustments, such as maximum allowable temperature or maximum ultrasonic amplitude. Finally, the fuzzy control output that meets the safety constraints is defuzzified to generate adjustment parameters. Defuzzification involves converting fuzzy language output into precise numerical output by adjusting parameters. The process of determining the specific correction amount for the current control parameters commonly uses methods such as the center of gravity method or the maximum membership method.

[0086] For example, the deviation parameter obtained by comparing the sintering degree evaluation parameter with the target sintering parameter. The deviation is +3%, meaning the actual sintering degree lags behind the target value by 3%. The system first fuzzifies this +3%, assuming the membership function transforms it into a fuzzy input variable where the deviation is "positive and large." The fuzzy inference module, based on a rule base such as "if the deviation is positive and large, the adjustment amount should be negative and moderate," generates a fuzzy control output representing a "moderate negative adjustment." Before defuzzification, the system checks safe operating range constraints, such as the ultrasonic amplitude adjustment amount not exceeding -5 micrometers. If the fuzzy control output, after initial defuzzification, is -6 micrometers, the system corrects it to -5 micrometers based on the safety constraints, ultimately generating the adjustment parameter. The value is -5 micrometers. This adjustment parameter will be used in conjunction with the current ultrasound amplitude control state to generate new, safer updated control parameters, such as reducing the ultrasound amplitude by 5 micrometers.

[0087] S5. Use the updated control parameters to perform feedback control on the subsequent application of ultrasonic vibration and sintering process.

[0088] Specifically, the first step is to convert the updated control parameters generated in the previous step into executable sintering equipment instructions. The updated control parameters are a set of ultrasonic vibration parameters including the latest frequency and amplitude, and sintering process parameters including heating rate and holding temperature. These parameters are transmitted to the sintering equipment and the ultrasonic generator through corresponding interfaces. Subsequently, the sintering equipment adjusts its output in real time according to the received updated control parameters, applying ultrasonic vibration and heat treatment to the metal powder. Specifically, the ultrasonic generator adjusts the transducer output according to the frequency and amplitude, changing the mechanical vibration characteristics applied to the powder; simultaneously, the sintering furnace temperature control system adjusts the heating power according to the heating rate and holding temperature, controlling the temperature changes inside the furnace. Under this feedback control, the trajectory of the sintering process is dynamically corrected, bringing it closer to the preset ideal target sintering parameters. Under the new control parameters, the next iteration begins, continuously acquiring real-time echo signals and generating ultrasonic detection signals, thereby again evaluating the degree of sintering and adjusting parameters, forming a continuous closed-loop control.

[0089] Optionally, the method further includes:

[0090] Based on the updated control parameters, a sintering control command is generated;

[0091] Execute the sintering control command to bring the sintering process into an optimized sintering state;

[0092] Monitor the optimized sintering state and record its correspondence with the updated control parameters, and update the knowledge system used to generate the initial control parameters.

[0093] Specifically, firstly, based on the generated updated control parameters, sintering control instructions are generated. These instructions translate abstract updated control parameters, such as new amplitude values ​​and new heating rates, into specific operational codes or signal sequences that the sintering equipment can recognize and execute. Subsequently, the sintering equipment executes these instructions, for example, adjusting the frequency and power of the ultrasonic generator while simultaneously regulating the heating elements and temperature of the sintering furnace, thereby bringing the sintering process into an optimized sintering state. The optimized sintering state refers to the metal powder sintering in a manner closer to the ideal densification curve under the guidance of the updated control parameters. Next, in the optimized sintering state, its operational data is continuously monitored and recorded, including real-time sintering temperature, ultrasonic vibration parameters, and the latest sintering degree assessment parameters, and a correspondence is established between this monitoring data and the currently used updated control parameters. Finally, using this recorded correspondence, the knowledge system used to generate the initial control parameters is updated. The knowledge system is a database or empirical model storing the mapping relationship between material properties and optimal initial control parameters. By inputting the effective control experience under the newly acquired optimized sintering state, self-learning and iterative improvement are achieved.

[0094] For example, the system generates updated control parameters based on sintering degree evaluation parameters, requiring a 5-degree Celsius increase in sintering temperature and a 1-micrometer increase in ultrasonic amplitude. The system translates these values ​​into specific sintering control commands, such as sending digital signals to the temperature controller and ultrasonic generator and executing them to bring the sintering process into an optimized sintering state. Over the next 10 minutes, the system continuously monitors the actual temperature of the sintering furnace, the actual amplitude of the ultrasonic waves, and the resulting new sintering degree evaluation parameters, such as an increase in density from 88% to 89.5%. The system uses this experience of "increasing temperature by 5 degrees Celsius and amplitude by 1 micrometer, resulting in a 1.5% increase in density within 10 minutes" as a valid case, recording its correspondence with the original updated control parameters. Finally, this new valid experience is used to update the system's knowledge base. For example, the rule weight in the knowledge base that "at a density of around 88%, increasing the temperature is more effective than increasing the amplitude" for this type of metal powder may be strengthened or revised so that the system can more accurately generate initial control parameters when encountering similar sintering states in the future.

[0095] Based on the same inventive concept, such as Figure 4 As shown, the present invention also provides a metal powder sintering degree analysis system based on ultrasonic vibration assistance, the system comprising:

[0096] The parameter acquisition module is used to acquire the initial vibration parameters and initial process parameters used to define the initial sintering conditions, and to generate the initial control parameters.

[0097] An ultrasonic signal generation module is used to apply ultrasonic vibration to metal powder based on the initial control parameters, acquire real-time echo signals during sintering, and generate ultrasonic detection signals.

[0098] The signal analysis and evaluation module is used to analyze the ultrasonic detection signal and generate sintering degree evaluation parameters;

[0099] An update control parameter generation module is used to adjust the initial control parameters and generate updated control parameters based on the sintering degree evaluation parameters.

[0100] The control execution module is used to provide feedback control for the subsequent application of ultrasonic vibration and sintering process using the updated control parameters.

[0101] It should be noted that the electrical connections between the various units described above do not necessarily represent direct or indirect connections. Any indirect connection method can be applied to the embodiments of the present invention as long as it achieves the purpose of the present invention. The above descriptions are merely exemplary embodiments of the present invention and should not be construed as limiting the scope of the present invention.

[0102] All equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Those skilled in the art will readily conceive of other embodiments of this invention upon considering the specification and the disclosure of practical truth. This application is intended to cover any variations, uses, or adaptations of this invention that follow the general principles of this invention and include common knowledge or conventional techniques in the art not described herein.

Claims

1. A method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance, characterized in that, The method includes: Obtain the initial vibration parameters and initial process parameters used to define the initial sintering conditions, and generate the initial control parameters; Based on the initial control parameters, ultrasonic vibration is applied to the metal powder, and real-time echo signals are acquired during the sintering process to generate ultrasonic detection signals. The ultrasonic detection signal is analyzed to generate sintering degree evaluation parameters, including: extracting sound velocity and attenuation features from the ultrasonic detection signal to generate signal feature parameters; calculating the density and porosity of the sintered metal powder body based on the signal feature parameters to generate physical state parameters; and fusing the physical state parameters to generate sintering degree evaluation parameters, including: converting the signal feature parameters into preliminary evaluation data; acquiring the real-time sintering temperature and performing error correction on the preliminary evaluation data to generate corrected data; and acquiring historical sintering data and fusing it with the corrected data to generate physical state parameters. Based on the sintering degree evaluation parameters, the initial control parameters are adjusted to generate updated control parameters; The updated control parameters are used to provide feedback control for the subsequent application of ultrasonic vibration and sintering processes.

2. The method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance according to claim 1, characterized in that, The step of adjusting the initial control parameters to generate updated control parameters based on the sintering degree evaluation parameters includes: Obtain the target sintering parameters used to define the ideal sintering process, and compare them with the sintering degree evaluation parameters to generate deviation parameters; Based on the deviation parameters, adjustment parameters are generated; Based on the adjustment parameters and the current control state, updated control parameters are generated.

3. The method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance according to claim 1, characterized in that, The process of acquiring real-time echo signals and generating ultrasonic detection signals includes: Ultrasonic pulses are emitted toward metal powder and the echoes are received to generate raw detection data. The original detection data is subjected to bandpass filtering to generate a filtered signal; The filtered signal is amplified and digitally converted to generate an ultrasonic detection signal.

4. The method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance according to claim 1, characterized in that, The process of obtaining initial vibration parameters and initial process parameters for defining initial sintering conditions, and generating initial control parameters, includes: Obtain the material property parameters of the metal powder to be sintered; Based on the aforementioned material property parameters, the initial vibration parameters and initial process parameters are obtained; The initial vibration parameters and the initial process parameters are combined to generate the initial control parameters.

5. The method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance according to claim 1, characterized in that, The method further includes: Based on the updated control parameters, a sintering control command is generated; Execute the sintering control command to bring the sintering process into an optimized sintering state; Monitor the optimized sintering state and record its correspondence with the updated control parameters, and update the knowledge system used to generate the initial control parameters.

6. The method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance according to claim 2, characterized in that, The process of generating adjustment parameters based on the deviation parameters includes: The deviation parameter is fuzzified to generate fuzzy input variables; Inference is performed on the fuzzy input variables to generate fuzzy control output; The fuzzy control output is compared with the preset safe operating range constraints, and defuzzification is performed to generate adjustment parameters.

7. The method for analyzing the degree of sintering of metal powder based on ultrasonic vibration assistance according to claim 3, characterized in that, The process of emitting ultrasonic pulses to the metal powder and receiving the echoes to generate raw detection data includes: An ultrasonic pulse is emitted to the metal powder and a linear scan is performed on the metal powder to receive echo signals from the powder particle boundaries and internal defects. The amplitude and time-of-flight information of the echo signal are collected to generate raw detection data.

8. A metal powder sintering degree analysis system based on ultrasonic vibration, applied to the metal powder sintering degree analysis method based on ultrasonic vibration as described in any one of claims 1-7, characterized in that, The system includes: The parameter acquisition module is used to acquire the initial vibration parameters and initial process parameters used to define the initial sintering conditions, and to generate the initial control parameters. An ultrasonic signal generation module is used to apply ultrasonic vibration to metal powder based on the initial control parameters, acquire real-time echo signals during sintering, and generate ultrasonic detection signals. The signal analysis and evaluation module is used to analyze the ultrasonic detection signal and generate sintering degree evaluation parameters, including: extracting sound velocity and attenuation features from the ultrasonic detection signal to generate signal feature parameters; calculating the density and porosity of the sintered metal powder body based on the signal feature parameters to generate physical state parameters; and fusing the physical state parameters to generate sintering degree evaluation parameters, including: converting the signal feature parameters into preliminary evaluation data; acquiring the real-time sintering temperature and performing error correction on the preliminary evaluation data to generate corrected data; and acquiring historical sintering data and fusing it with the corrected data to generate physical state parameters. An update control parameter generation module is used to adjust the initial control parameters and generate updated control parameters based on the sintering degree evaluation parameters. The control execution module is used to provide feedback control for the subsequent application of ultrasonic vibration and sintering process using the updated control parameters.

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