Force and heat on-line monitoring device and method for composite explosive compression molding

Abstract

The invention discloses a force and heat on-line monitoring device and method for composite explosive compression molding, and relates to the technical field of composite explosive production equipment and process. The technical scheme is characterized in that aiming at the characteristic that a lower punch is more complex in stress during compression, pressure and temperature distribution is captured in real time by arranging a film sensor; the macroscopic mechanical behaviors among the materials are directly reflected, and accurate data support is provided for process optimization. The film sensor breaks through the limitation of traditional single parameter measurement in a construction mode that a temperature wire is embedded in a piezoresistive sensor, dynamic changes of a pressure field and a temperature field can be synchronously obtained, the process control precision of mixed explosive production is improved, compression molding process parameters are optimized, the product quality is improved, and the production cost is reduced. And the working intensity and the safety risk of operators are reduced.

Description

Technical Field

[0001] This invention relates to the field of equipment and process technology for the production of mixed explosives, and more specifically, to a device and method for online monitoring of force and heat during the pressing and molding of mixed explosives. Background Technology

[0002] In recent years, the increasingly tense international war situation, the complex and harsh battlefield environment, and the rapid development of new weapons and ammunition have placed higher demands on the molding quality and performance, compression safety, and digital automation level of press-fit explosives.

[0003] Compression molding is a process that uses external pressure to press explosive powder or granules into the desired geometric shape, giving them a certain density and strength. It has a wide range of applications, suitable for various types of explosives, and the compression process does not produce molding defects such as bubbles or shrinkage. The resulting products are of high quality, with good uniformity of charge density, stable detonation velocity, and high precision.

[0004] However, current research on the mechanism of the pressing process still has significant gaps. The mechanical and material mechanisms of explosive forming and defect generation are not fully understood, remaining largely in a "black box" or "gray box" state. In industrial production, process parameters and quality control still rely primarily on experience and extensive trial-and-error experiments. Safety accidents during pressing production occur occasionally, and sufficient theoretical support is lacking. Taking polymer-bonded explosives (PBX) as an example, their pressing process involves a complex dynamic process characterized by the movement, deformation, densification, and bonding of binder-coated explosive particles under thermo-mechanical coupling, accompanied by localized breakage and damage to the explosive particles. However, due to the lack of real-time research methods, existing experiments mostly rely on post-hoc observation and characterization, making it difficult to deeply study the specific behaviors of the explosive particle system under external thermo-mechanical coupling during the pressing process, such as movement, deformation, localized damage, densification, and bonding, thus creating a process "blind spot." Summary of the Invention

[0005] The purpose of this invention is to provide an online monitoring device and method for force and heat during the compression molding of mixed explosives. By revealing the macroscopic mechanical behavior and its mechanism of action during the compression process, this invention provides a scientific basis for optimizing process parameters and improving product quality.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: an online monitoring device for force and heat in the pressing and molding of mixed explosives, wherein the online monitoring device is used in conjunction with an explosive pressing device, and the explosive pressing device includes a middle mold, an upper punch and / or a lower punch;

[0007] The online monitoring device includes:

[0008] Thin-film sensors are distributed on the inner surface of the lower punch;

[0009] The data acquisition module utilizes a data acquisition device to perform its function, which is used to acquire real-time data from the thin-film sensor.

[0010] The data processing module utilizes a processor to perform its functions, which are used to process and analyze the data acquired by the signal acquisition module.

[0011] The data transmission module enables data transmission via methods including USB data cable, 5G, and Bluetooth.

[0012] The display module utilizes a display screen to realize its function, which is used to display the force distribution and changing trend analyzed by the data processing module in real time;

[0013] The alarm module functions through warning devices including buzzers and indicator lights, and is used to issue an alarm when the force or temperature exceeds a preset range.

[0014] A controller is used to regulate the coordinated operation between various components.

[0015] The present invention is further configured such that: the thin film sensor is made by integrating a thin film pressure sensor with a temperature sensor, wherein the thin film pressure sensor is a high temperature resistant and corrosion resistant piezoresistive sensor, and a temperature wire is arranged inside it to collect temperature signals.

[0016] The present invention is further configured such that: five tap lines are distributed at equal intervals in both the horizontal and vertical directions on the inner surface of the lower punch, and a thin film pressure sensor is set at the intersection of each horizontal and vertical tap line.

[0017] The present invention is further configured such that temperature sensors are uniformly distributed on the inner surface of the lower punch.

[0018] The invention is further configured such that: a through hole is provided at the bottom edge of the explosive pressing device, the thin film sensor extends out from the through hole and connects to the data acquisition device, and then the data acquisition device is fixed.

[0019] This invention further provides a method for online monitoring of force and heat during the compression molding of mixed explosives based on the aforementioned monitoring device. During the compression molding process of the mixed explosives, the online force and heat monitoring device is activated. A thin-film sensor monitors changes in pressure and heat, converting physical signals into electrical signals. A data acquisition unit collects the electrical signals and performs A / D conversion to generate digital signals. A data transmission module transmits the digital signals to a data processing module. The data processing module calibrates, filters, and preprocesses the collected data, establishing mathematical relationships or calibration curves to obtain relevant data, graphs, tables, and analysis reports on force and heat changes during the compression molding process of the mixed explosives. These data are displayed in real time by a display module. An alarm module issues an alarm when the applied force or temperature exceeds a preset range.

[0020] In summary, the present invention has the following beneficial effects:

[0021] This invention addresses the more complex forces acting on the lower punch during pressing by deploying thin-film sensors to capture pressure and temperature distribution in real time, directly reflecting the macroscopic mechanical behavior of materials and providing precise data support for process optimization. Furthermore, a force-thermal coupled thin-film sensor (piezoresistive sensor + embedded temperature wire) is designed, overcoming the limitations of traditional single-parameter measurements. It can simultaneously acquire dynamic changes in the pressure and temperature fields, improving the process control precision in mixed explosives production, facilitating the optimization of pressing process parameters, improving product quality, and reducing operator workload and safety risks. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the pressing mold in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of a thin-film sensor in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the thin-film sensor installation in an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram illustrating the real-time data display in an embodiment of the present invention. Detailed Implementation

[0026] The following is in conjunction with the appendix Figure 1-4 The present invention will be described in further detail below.

[0027] Example: An online monitoring device for force and heat in the pressing and molding of mixed explosives. The online monitoring device is used in conjunction with an explosive pressing device, which includes a middle mold, an upper punch and / or a lower punch.

[0028] The online monitoring device includes thin-film sensors, a data acquisition module, a data processing module, a data transmission module, a display module, an alarm module, and a controller. The thin-film sensors are distributed on the inner surface of the lower punch; these sensors are made by integrating a thin-film pressure sensor with a temperature sensor. The thin-film pressure sensor is a high-temperature, corrosion-resistant piezoresistive sensor with a temperature wire arranged inside to collect temperature signals. Five tap lines are evenly spaced horizontally and vertically on the inner surface of the lower punch, with a thin-film pressure sensor placed at the intersection of each horizontal and vertical tap line. Temperature sensors are evenly distributed throughout the entire inner surface of the lower punch.

[0029] The data acquisition module utilizes a data acquisition unit to collect real-time data from a thin-film sensor. A through-hole is located at the bottom edge of the explosive compression device, through which the thin-film sensor wires connect to the data acquisition unit, which is then fixed in place. The data processing module uses a processor to process and analyze the data acquired by the signal acquisition module. The data transmission module transmits data via methods including USB cable, 5G, and Bluetooth. The display module uses a display screen to show the force distribution and trends analyzed by the data processing module in real time. The alarm module uses warning devices including a buzzer and indicator lights to issue an alarm when the force or temperature exceeds a preset range. The controller regulates the coordinated operation of all components.

[0030] Due to the unique nature of the compression-loading process, and the variations in the type of explosive and compression method used, the compression process will differ. In this embodiment, a certain amount of explosive is first weighed, then placed into a prepared mold, followed by the insertion of an upper punch to compress the explosive. This process is then repeated with pressure holding and demolding. Finally, the quality of the compressed explosive is inspected. Once the explosive passes inspection, it is packaged and numbered, and finally, the explosive charge is loaded into the projectile.

[0031] In this embodiment, an inert material with similar properties and readily available cost is used as a substitute for the energetic material during simulated drug compression. Taking the compression molding of ammonium aluminate sulfate granules as an example, a 75mm diameter mold is used to compress the granules into regular cylindrical drug cartridges. The specific drug compression implementation steps are as follows:

[0032] Based on the 75mm diameter mold structure, the dimensions of the thin-film sensor were designed. The sensor uses a 4.5mm wide tap line, with three temperature measurement points evenly distributed radially to ensure complete coverage of the lower punch surface. Subsequently, to facilitate wiring connections, a 0.5mm × 4.7mm through-hole was created at the edge of the mold for wire routing. This through-hole directly connects to the data acquisition module, such as... Figure 3 As shown.

[0033] The simulated particles were weighed using an electronic balance. The weighed sample of the drug particles was placed into the pressing mold. After the mold was filled, the process parameters for drug column pressing were set according to the actual production and processing conditions: the drug column pressing method was unidirectional pressing, the pressing force was set to 15MPa, the pressing speed was 2mm / s, and the holding time of the mold and the material during the pressing process was set to 100s.

[0034] During the compression molding process of mixed explosives, the online force and heat monitoring device is activated. A thin-film sensor monitors pressure and temperature changes, converting physical signals into electrical signals. The data acquisition unit collects these electrical signals, performs A / D conversion, and generates digital signals. The data is then uploaded to a computer or other processor capable of handling digital signals via USB cable. The collected data is calibrated, filtered, and preprocessed. Combined with the mathematical relationships or calibration curves established during calibration, the magnitude, duration, and location of the force and pressure acting on the thin-film sensor, as well as the corresponding temperature changes, can be obtained. Real-time display of relevant data, heat change graphs, and pressure cloud maps can be achieved, generating pressure distribution maps, 3D visualization models, and providing detailed data analysis reports, such as… Figure 4 As shown, the alarm module displays the information in real time and issues an alarm when the applied force or temperature exceeds the preset range.

[0035] Working Principle: During the compression of the propellant, two methods are used, one for unidirectional compression and the other for bidirectional compression, depending on the movement of the punch relative to the die. In unidirectional compression, the die remains stationary, while the upper or lower punch moves relative to it in one direction. However, due to the poor flowability of the propellant within the die cavity, uneven density distribution can easily occur. In bidirectional compression, both the upper and lower punches move relative to the die in opposite directions, with consistent speeds and equal strokes. Because the propellant moves from both ends towards the center under pressure within the die cavity, it exhibits good flowability and uniform density.

[0036] In the process of unidirectional or bidirectional compression of explosives, the pressure measurement of the lower punch is more critical than that of the upper punch. The reason is:

[0037] During the unidirectional pressing process, the bottom directly bears the reaction force of the material, including the pressure of the upper punch, the frictional resistance between powder particles, and the constraint force of the mold, comprehensively reflecting the actual forming pressure (if only the upper punch is measured, the frictional loss at the bottom will be ignored). Furthermore, the heat generated by the friction between the mold and the material is conducted to the bottom, and the heat dissipation at the bottom is slower, resulting in a more stable temperature signal that can characterize the overall thermal effect.

[0038] During bidirectional compression, both the upper and lower punches apply pressure simultaneously. However, the explosive experiences uneven axial pressure distribution due to frictional resistance during compression, forming a "neutral layer" (i.e., the area of ​​minimum pressure), typically located near the center of the die. The lower punch experiences greater resistance because it must overcome the friction between the explosive and the die wall, as well as the resistance to the explosive's downward flow. The upper punch primarily pushes the explosive downwards, experiencing less reaction force. Measuring the lower punch pressure more accurately reflects the actual forming resistance, explosive filling uniformity, and potential defects, providing greater guidance for process control and die life assessment.

[0039] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A device for online monitoring of force and heat during the compression molding of mixed explosives, characterized in that: The online monitoring device is used in conjunction with the explosive pressing device, which includes a middle mold, an upper punch, and / or a lower punch. The online monitoring device includes: Thin-film sensors are distributed on the inner surface of the lower punch; The data acquisition module utilizes a data acquisition device to perform its function, which is used to acquire real-time data from the thin-film sensor. The data processing module utilizes a processor to perform its functions, which are used to process and analyze the data acquired by the signal acquisition module. The data transmission module enables data transmission via methods including USB data cable, 5G, and Bluetooth. The display module utilizes a display screen to realize its function, which is used to display the force distribution and changing trend analyzed by the data processing module in real time; The alarm module functions through warning devices including buzzers and indicator lights, and is used to issue an alarm when the force or temperature exceeds a preset range. A controller is used to regulate the coordinated operation between various components.

2. The online monitoring device for force and heat during the compression molding of mixed explosives according to claim 1, characterized in that: The thin-film sensor is made by integrating a thin-film pressure sensor with a temperature sensor. The thin-film pressure sensor is a high-temperature and corrosion-resistant piezoresistive sensor, with a temperature wire arranged inside to collect temperature signals.

3. The online monitoring device for force and heat during the compression molding of mixed explosives according to claim 2, characterized in that: Five tap lines are evenly spaced in both the horizontal and vertical directions on the inner surface of the lower punch. A thin-film pressure sensor is set at the intersection of each horizontal and vertical tap line.

4. The online monitoring device for force and heat during the compression molding of mixed explosives according to claim 2, characterized in that: Temperature sensors are evenly distributed on the inner surface of the lower punch.

5. The online monitoring device for force and heat during the compression molding of mixed explosives according to claim 1, characterized in that: The explosive pressing device has a through hole at its bottom edge. The thin-film sensor extends from the through hole and connects to the data acquisition device, which is then fixed in place.

6. A method for online monitoring of force and heat during the compression molding of mixed explosives based on the monitoring device described in any one of claims 1-5, characterized in that: During the pressing and molding process of the mixed explosives, the online force and heat monitoring device is activated. The pressure and heat changes are monitored through a thin-film sensor, and the physical signal is converted into an electrical signal. The data acquisition unit collects the electrical signal and performs A / D conversion to generate a digital signal. The data transmission module transmits the digital signal to the data processing module. The data processing module calibrates, filters, and preprocesses the collected data, establishes mathematical relationships or calibration curves, and obtains relevant data, graphs, tables, and analysis reports on the force and heat changes during the pressing and molding process of the mixed explosives. These data are displayed in real time through the display module. When the applied force or temperature exceeds the preset range, the alarm module issues an alarm.

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