Multi-state on-line monitoring system and method for molding sand in sand casting process

Abstract

The invention provides a multi-state on-line monitoring system and method for molding sand in a sand casting process, and belongs to the technical field of manual molding of sand casting. The system comprises a high-speed spectrometer, an optical fiber circulator, a wide-spectrum light source, a hardness sensor control circuit board, a computer and a sensor for simultaneously detecting the temperature, the humidity and the hardness of sand in the sand casting process. During data acquisition, probe light emitted by a wide-spectrum light source is transmitted to each sensor node through an optical fiber circulator, a high-speed spectrometer analyzes the central wavelength offset of an interference spectrum in real time, hardness electric signals are synchronously acquired, and a multi-physical field database containing spatial and temporal distribution characteristics is constructed. A neural network model is adopted for quality correlation analysis, and a parameter-defect mapping relation is established by training multiple sets of process data. According to the invention, in-situ synchronous measurement of three parameters of temperature, humidity and hardness is realized in sand casting for the first time, and the industrial problem that a molding sand state cannot be comprehensively reflected by traditional single parameter detection is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of manual molding in sand casting, and relates to an on-line monitoring system and method for multi-state of molding sand in the sand casting process. Background Art

[0002] Manual molding in sand casting is vividly called "a tricky job" in the industry. Its process characteristics can be summarized as "molding with eyes open and pouring with eyes closed". Although the molding quality can be preliminarily judged by visual inspection, there are many uncontrollable factors during the pouring process: whether the molten metal can be completely filled, whether pores or shrinkage porosity defects will occur during the solidification process, and whether sand sticking or slag inclusion appears on the surface of the casting. These typical defects lead to a high rejection rate of the traditional manual molding process. It should be noted that even if performed by experienced operators, it is difficult to completely avoid quality fluctuations, reflecting the high dependence of this process on the operator's skills and the limitations of quality control.

[0003] To break through this industry bottleneck and achieve on-line optimization and active control of the casting process, it is of great engineering value to develop a multi-parameter on-line monitoring system for sand temperature, humidity and hardness. This technical solution implants a three-parameter integrated sensor in the formed sand mold, collects the physical property data of the molding sand in real time, constructs a multi-factor coupling analysis model by combining a large amount of experimental data, and finally establishes a quantitative relationship between the physical property parameters of the sand mold and the casting quality. Based on this, the prior art (the "Numerical Simulation of Temperature Field of Aluminum Alloy Wheels in Sand Gravity Casting" published by Jia Ruijiao et al., and the "Calibration Method and Uncertainty Analysis of Wet Mold Surface Hardness Gauge for Casting" published by Jin Jing) respectively use thermometers and hardness gauges to analyze the temperature and hardness of sand casting, but the former is limited by the insufficient accuracy of traditional temperature measurement means, and the latter only focuses on single-parameter detection. It should be particularly noted that there are currently no mature cases at home and abroad that integrate the on-line monitoring systems of temperature, humidity and hardness and apply them to manual molding in sand casting.

[0004] In summary, designing a sensing system that can accurately measure the temperature, humidity and hardness of the sand mold simultaneously to evaluate the quality of casting products has important engineering application value and teaching value. Summary of the Invention

[0005] In order to solve the above problems, the present invention proposes an on-line monitoring system and method for multi-state of molding sand in the sand casting process. The system effectively solves the technical bottleneck of "uncontrollable process and quality depending on experience" in the traditional process by collecting the data of sand mold temperature, humidity and hardness in real time and constructing a mapping model between process parameters and casting quality. Specifically, this technical solution realizes the quantitative evaluation of the sand mold state before pouring and the dynamic compensation of process parameters, and for the first time introduces the multi-physical field collaborative monitoring technology into the manual molding process in the casting field. It has great application prospects in the field of manual molding in sand casting.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] An on-line multi-state monitoring system for molding sand in sand casting process, comprising a high-speed spectrometer 3, an optical fiber circulator 2, a broadband light source 4, a control circuit 6, a computer 5, and a sensor 13 for simultaneously detecting the temperature, humidity and hardness of molding sand 10 in sand casting process; the sensor 13 includes a hardness sensor 1 and an optical fiber sensor 7, and the optical fiber sensor 7 integrates two fiber Bragg gratings for simultaneous sensing of temperature and humidity; the sensor 13 is respectively connected to the optical fiber circulator 2 and the control circuit 6, and the control circuit 6 is also connected to the computer 5, and the hardness detected by the optical fiber sensor 7 in the sensor 13 is transmitted to the computer 5 through the control circuit 6; the optical fiber circulator 2 is also respectively connected to the high-speed spectrometer 3 and the broadband light source 4, and both the high-speed spectrometer 3 and the broadband light source 4 are connected to the computer 5, and the optical fiber circulator 2 is used for circulating the optical path, which can not only transmit the detection light emitted by the broadband light source 4 to the optical fiber sensor 7, but also return the center wavelength shift amount of the interference spectrum generated by the optical fiber sensor 7 to the high-speed spectrometer 3 in the form of an optical signal; the high-speed spectrometer 3 is used for demodulating the center wavelength shift amount of the interference spectrum caused by the change of the fiber Bragg grating with temperature and humidity; the broadband light source 4 is used for emitting detection light; the computer 5 is used for receiving and processing the temperature, humidity and hardness data from the high-speed spectrometer 3 and the control circuit 6, and controlling the broadband light source 4 to emit detection light.

[0008] Furthermore, the optical fiber sensor 7 and the hardness sensor 1 are integrally installed in a cylindrical protective shell 8 for synchronously detecting the temperature, humidity and hardness data of the molding sand 10 to assist in analyzing the quality of the sand casting product. The bottom of the cylindrical protective shell 8 is filled with replaceable porous material 9 to ensure the rapid circulation of gas between the molding sand 10 and the optical fiber sensor 7, so that the optical fiber sensor 7 can quickly and accurately detect the temperature and humidity in the molding sand 10.

[0009] Furthermore, the pore diameter of the porous material 9 is smaller than the particle diameter of the molding sand 10, and the strength is such that the molding sand 10 will not damage it.

[0010] A method for online monitoring of multiple states of molding sand in sand casting process is implemented by using the above-mentioned online monitoring system for multiple states of molding sand in sand casting process; the sensor 13 is inserted into multiple detection sites of the molding sand 10. The computer 5 controls the broadband light source 4 to emit detection light, which is transmitted to the fiber optic sensor 7 in the sensor 13 through the fiber optic circulator 2; the fiber optic sensor 7 real-time monitors the offset of the interference spectrum center wavelength of the fiber Bragg grating caused by temperature and humidity changes at each detection site; and through the fiber optic circulator 2, the offset of the interference spectrum center wavelength is returned to the high-speed spectrometer 3 in the form of an optical signal, and finally the offset of the interference spectrum center wavelength is demodulated and transmitted to the computer 5. The hardness of each detection site is monitored by the hardness sensor 1 in the sensor 13 and transmitted to the computer 5 through the control circuit 6. The temperature, humidity and hardness of different detection sites in the molding sand 10 are all output by the computer 5 to realize the simultaneous measurement of the three parameters.

[0011] Further, the offset of the interference spectrum center wavelength demodulated by the high-speed spectrometer 3 caused by the temperature and humidity is established into a data set, and the data set is used to train the deep learning neural network to improve the accuracy of spectral resolution, and further improve the sensing sensitivity of temperature and humidity.

[0012] The beneficial effects of the present invention: The present invention provides an online monitoring system and method for multiple states of molding sand in sand casting process. Through the innovative design of integrating fiber optic temperature / humidity sensors and hardness sensors, the in-situ synchronous measurement of temperature, humidity and hardness is realized for the first time in sand casting, solving the industry problem that traditional single-parameter detection (such as thermometer or hardness meter) cannot comprehensively reflect the state of molding sand. Based on the deep learning algorithm, the coupled influence of temperature and humidity on the fiber wavelength drift is effectively separated. By real-time collecting the data of multi-position sensors, the system can predict the probability of shrinkage porosity, slag inclusion and other defects 20 minutes before pouring, greatly reducing the rejection rate. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of an online monitoring system for multiple states of molding sand in sand casting process;

[0014] Figure 2 It is a schematic diagram of the sensor for simultaneous detection of temperature, humidity and hardness of molding sand in sand casting process of the present invention;

[0015] Figure 3 It is an enlarged view of the fiber optic sensor in the present invention;

[0016] In the figure: 1 hardness sensor; 2 optical fiber circulator; 3 high-speed spectrometer; 4 broad-spectrum light source; 5 computer; 6 control circuit; 7 optical fiber sensor; 8 protective shell; 9 porous material; 10 molding sand; 11 fiber Bragg grating A; 12 fiber Bragg grating B; 13 sensor. Specific implementation manner

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0018] Figure 1 It is a schematic diagram of an on-line monitoring system for multi-state molding sand in the sand casting process of the present invention. As Figure 1 shown, it includes a high-speed spectrometer 3, an optical fiber circulator 2, a broad-spectrum light source 4, a control circuit 6, a computer 5, and a sensor 13 for simultaneously detecting the temperature, humidity and hardness of the molding sand 10 in the sand casting process; the sensor 13 includes a hardness sensor 1 and an optical fiber sensor 7. The optical fiber sensor 7 integrates two fiber Bragg gratings for simultaneous sensing of temperature and humidity; the sensor 13 is respectively connected to the optical fiber circulator 2 and the control circuit 6, and the control circuit 6 is also connected to the computer 5. The hardness detected by the optical fiber sensor 7 in the sensor 13 is transmitted to the computer 5 through the control circuit 6; the optical fiber circulator 2 is also respectively connected to the high-speed spectrometer 3 and the broad-spectrum light source 4. Both the high-speed spectrometer 3 and the broad-spectrum light source 4 are connected to the computer 5. The optical fiber circulator 2 is used for circulating the optical path, which can not only transmit the detection light emitted by the broad-spectrum light source 4 to the optical fiber sensor 7, but also return the center wavelength shift amount of the interference spectrum generated by the optical fiber sensor 7 to the high-speed spectrometer 3 in the form of an optical signal; the high-speed spectrometer 3 is used for demodulating the center wavelength shift amount of the interference spectrum caused by the change of the fiber Bragg grating with temperature and humidity; the broad-spectrum light source 4 is used for emitting detection light; the computer 5 is used for receiving and processing the temperature, humidity and hardness data from the high-speed spectrometer 3 and the control circuit 6, and controlling the broad-spectrum light source 4 to emit detection light.

[0019] Figure 2 It is a schematic diagram of a sensor for simultaneously detecting the temperature, humidity and hardness of molding sand in the sand casting process of the present invention. As Figure 2As shown in the figure, a sensor for simultaneously detecting the temperature, humidity, and hardness of molding sand in a sand casting process provided by an embodiment of the present invention. The fiber optic sensor 7 and the hardness sensor 1 are integrally installed in a cylindrical protective housing 8 for synchronously detecting the temperature, humidity, and hardness data of the molding sand 10 to assist in analyzing the quality of sand casting castings. The bottom of the cylindrical protective housing 8 is filled with replaceable porous material 9 to ensure the rapid circulation of gas between the molding sand 10 and the fiber optic sensor 7, so that the fiber optic sensor 7 can quickly and accurately detect the temperature and humidity in the molding sand 10. The pore diameter of the porous material 9 is smaller than the particle diameter of the molding sand 10, and the strength is such that the molding sand 10 will not damage it.

[0020] Figure 3 is an enlarged view of the fiber optic sensor in the present invention. As Figure 3 shown, the fiber optic sensor in the present invention includes two fiber Bragg gratings. Among them, the fiber Bragg grating A11 is directly used for temperature sensing, and the fiber Bragg grating B12 needs to be coated with a humidity-sensitive material to achieve humidity sensing.

[0021] During use, the sensor 13 is inserted into multiple detection sites of the molding sand 10. The computer 5 controls the broadband light source 4 to emit detection light, which is transmitted to the fiber optic sensor 7 in the sensor 13 through the fiber optic circulator 2; the fiber optic sensor 7 real-time monitors the offset of the center wavelength of the interference spectrum of the fiber Bragg grating caused by temperature and humidity changes at each detection site; and through the fiber optic circulator 2, the offset of the center wavelength of the interference spectrum is returned to the high-speed spectrometer 3 in the form of an optical signal, and finally the offset of the center wavelength of the interference spectrum is demodulated and transmitted to the computer 5. The hardness of each detection site is monitored by the hardness sensor 1 in the sensor 13 and transmitted to the computer 5 through the control circuit 6. The temperature, humidity, and hardness of different detection sites in the molding sand 10 are all output by the computer 5 to achieve the simultaneous measurement of the three parameters. The offset of the center wavelength of the interference spectrum demodulated by the high-speed spectrometer 3 caused by temperature and humidity is established into a data set, and the data set is used to train a deep learning neural network to improve the accuracy of spectral resolution, thereby improving the sensing sensitivity of temperature and humidity.

[0022] The sampling points of the high-speed spectrometer 3 are 1024. The width of the broadband light source 4 is 80 nm.

[0023] The center wavelengths of the two fiber Bragg gratings are respectively located at 1535 nm and 1565 nm, and their reflectivities are both greater than 90%. This can achieve simultaneous sensing of temperature and humidity in a large dynamic range without mutual interference.

[0024] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An on-line monitoring system for multi-state molding sand in sand casting process, characterized in that It includes a high-speed spectrometer (3), an optical fiber circulator (2), a broad-spectrum light source (4), a control circuit (6), a computer (5), and a sensor (13) for simultaneously detecting the temperature, humidity, and hardness of molding sand (10) in the sand casting process; the sensor (13) includes a hardness sensor (1) and an optical fiber sensor (7), and the optical fiber sensor (7) integrates two fiber Bragg gratings for simultaneous temperature and humidity sensing; the sensor (13) is respectively connected to the optical fiber circulator (2) and the control circuit (6), and the control circuit (6) is also connected to the computer (5). The hardness detected by the optical fiber sensor (7) in the sensor (13) is transmitted to the computer (5) through the control circuit (6); the optical fiber circulator (2) is also respectively connected to the high-speed spectrometer (3) and the broad-spectrum light source (4), and both the high-speed spectrometer (3) and the broad-spectrum light source (4) are connected to the computer (5). The optical fiber circulator (2) is used for circulating the optical path, which can not only transmit the detection light emitted by the broad-spectrum light source (4) to the optical fiber sensor (7), but also return the central wavelength offset of the interference spectrum generated by the optical fiber sensor (7) to the high-speed spectrometer (3) in the form of an optical signal; the high-speed spectrometer (3) is used for demodulating the central wavelength offset of the interference spectrum caused by the change of the fiber Bragg grating with temperature and humidity; the broad-spectrum light source (4) is used for emitting detection light; the computer (5) is used for receiving and processing the temperature, humidity, and hardness data from the high-speed spectrometer (3) and the control circuit (6), and controlling the broad-spectrum light source (4) to emit detection light.

2. The multi-state on-line monitoring system for molding sand in a sand casting process according to claim 1, characterized in that, The optical fiber sensor (7) and the hardness sensor (1) are integrally installed in a cylindrical protective shell (8) for synchronously detecting the temperature, humidity, and hardness data of the molding sand (10) to assist in analyzing the quality of the sand casting casting product; the bottom of the cylindrical protective shell (8) is filled with replaceable porous material (9) to ensure the rapid circulation of gas between the molding sand (10) and the optical fiber sensor (7), so that the optical fiber sensor (7) can quickly and accurately detect the temperature and humidity in the molding sand (10).

3. An in-line monitoring system for multi-state green sand in a sand casting process according to claim 2, characterized in that, The pore diameter of the porous material (9) is smaller than the particle size of the molding sand (10), and the strength should ensure that the molding sand (10) will not damage it.

4. An online monitoring method for multi-state green sand in sand casting process, characterized in that, It is implemented by using an on-line monitoring system for multi-state molding sand in sand casting process according to any one of claims 1-3; the sensor (13) is inserted into multiple detection sites of the molding sand (10); the computer (5) controls the broadband light source (4) to emit detection light, which is transmitted to the fiber optic sensor (7) in the sensor (13) through the fiber optic circulator (2); the fiber optic sensor (7) monitors in real time the offset of the center wavelength of the interference spectrum of the fiber Bragg grating caused by temperature and humidity changes at each detection site; and through the fiber optic circulator (2), the offset of the center wavelength of the interference spectrum is returned to the high-speed spectrometer (3) in the form of an optical signal, and finally the offset of the center wavelength of the interference spectrum is demodulated and transmitted to the computer (5); the hardness of each detection site is monitored by the hardness sensor (1) in the sensor (13) and transmitted to the computer (5) through the control circuit (6); the temperature, humidity and hardness of different detection sites in the molding sand (10) are all output by the computer (5) to realize the simultaneous measurement of the three parameters.

5. A method for online monitoring of multi-state green sand in sand casting process according to claim 4, characterized in that The offset of the center wavelength of the interference spectrum demodulated by the high-speed spectrometer (3) caused by the temperature and humidity is established into a data set, and the data set is used to train the deep learning neural network to improve the accuracy of spectral resolution and further improve the sensing sensitivity of temperature and humidity.

Images