3D printed concrete mine similarity model internal defect detection and repair device and method

Abstract

A device and method for detecting and repairing internal defects in a 3D-printed concrete mine-like model. The device comprises: a partition disposed within the extrusion barrel, which divides the barrel's interior into a front cavity and a rear cavity; a main stirring screw driven by a main screw pump is disposed in the front cavity, the bottom of which is connected to the main nozzle; a secondary stirring screw driven by a secondary screw pump is disposed in the rear cavity, the bottom of which is connected to the auxiliary nozzle; automatic rangefinders A and B are disposed behind the main and auxiliary nozzles, respectively; and a residual material collection mechanism is disposed behind the auxiliary nozzle. Method: During the printing process, the distance signals A and B collected by the automatic rangefinders A and B are used to obtain a difference, and the presence of a defect is determined based on the relationship between the difference and the layer height. If a defect exists, the auxiliary nozzle is used to repair the defective area, and the residual material collection mechanism is used to collect excess material. The device and method can synchronously detect internal defects during the printing process and can repair the defects.

Description

Technical Field

[0001] The present invention belongs to the field of 3D printing concrete technology in the field of mining rock and soil, and specifically relates to a device and method for detecting and repairing internal defects of a 3D printed concrete mine similarity model. Background Art

[0002] Similarity physical simulation test is based on similarity theory. It uses materials with similar or close mechanical properties to the prototype, and makes a similar model at a certain scale according to actual geological conditions. The simulation test is then carried out on the model according to the theoretical similarity ratio to observe the deformation, displacement, etc. of the model. Based on this, the actual situation on site is analyzed and inferred. This is an effective means of inverting geological engineering conditions in the field of mining geotechnical engineering.

[0003] Conventional artificial casting methods for similar simulation tests are unable to reproduce actual conditions due to drawbacks such as difficulty controlling interlayer strength, difficulty maintaining uniform interlayer thickness, and the high manual workload. This is particularly true for the rock formations of engineering prototypes, rendering the tests ineffective. 3D printing, as an emerging technology, has established a research foundation and applications in rock mechanics and construction engineering. However, research based on 3D printing in my country's mining engineering sector is still in its infancy. Due to its high accuracy, 3D printing can effectively simulate real-world mining geological conditions, especially realistically simulating actual strata, offering broad application prospects for similar simulation tests in mines.

[0004] During 3D printing of similar models, due to changes in the printing path and printing direction, the printed models often have some incomplete defects at the corners. Existing 3D printing devices usually use a single-nozzle, one-way printing method, which cannot detect and repair internal defects during the printing process, resulting in a large error between the model strength and the engineering prototype. Therefore, there is an urgent need to provide a device that can repair internal defects during the printing process. Summary of the Invention

[0005] In response to the problems existing in the above-mentioned prior art, the present invention provides a device and method for detecting and repairing internal defects of a 3D printed concrete mine-like model. The device has a simple structure, low manufacturing cost, and easy operation. It can not only combine the advantages of 3D printed concrete for rock strata printing operations of mine-like models, but also perform online detection of incomplete internal defects during the printing process of similar physical models. At the same time, it also has the function of repairing defective parts, which can effectively improve the accuracy of the printed model's response to the actual situation of the prototype. The method has simple steps and low implementation cost. It can synchronously detect internal defects during the printing process. At the same time, it can effectively repair defective areas in a relatively automatic manner and ensure that the repaired effect meets the use requirements.

[0006] To achieve the above objectives, the present invention provides a 3D printed concrete mine similar model internal defect detection and repair device, comprising an extrusion barrel, a main screw pump, a main stirring screw, a main nozzle, an automatic distance meter A, a secondary screw pump, a secondary stirring screw, an auxiliary nozzle, an automatic distance meter B, a residual material collection mechanism, a solenoid valve, a display screen, and a controller;

[0007] A vertically extending partition is provided at the rear middle portion of the extrusion barrel; the partition divides the inner cavity of the extrusion barrel into a front cavity and a rear cavity;

[0008] The main screw pump is fixedly arranged above the center of the front cavity; the main stirring screw is rotatably arranged in the center of the front cavity, and a spiral conveying blade is fixedly connected to the outside of the main stirring screw, and the upper end of the main stirring screw is fixedly connected to the output shaft of the main screw pump; the main nozzle is funnel-shaped, and the size of its feed port is adapted to the size of the front cavity. The main nozzle is fixedly connected to the front side of the lower end of the extrusion barrel, and its feed port is connected to the lower end of the front cavity;

[0009] The automatic distance meter A is located at the rear side of the main nozzle and is fixedly installed on the outside of the main nozzle;

[0010] The auxiliary screw pump is fixedly arranged above the center of the rear cavity; the auxiliary stirring screw is rotatably arranged at the center inside the rear cavity, and a spiral conveying blade is fixedly connected to its exterior, and its upper end is fixedly connected to the output shaft of the auxiliary screw pump; the auxiliary nozzle is funnel-shaped, and the size of its feed port is adapted to the size of the rear cavity; the auxiliary nozzle is fixedly connected to the rear side of the lower end of the extrusion barrel, and its feed port is connected to the rear cavity, and the height of its discharge port is the same as that of the discharge port of the main nozzle;

[0011] The automatic distance meter B is located at the rear side of the auxiliary nozzle and is fixedly installed on the outside of the auxiliary nozzle;

[0012] The residual material collection mechanism is arranged at the lower rear side of the auxiliary nozzle, and includes a connecting rod, a collecting bin, a bucket, an impeller motor and an impeller; the upper end of the connecting rod is fixedly connected to the rear end of the extrusion barrel, and the lower end thereof extends to the lower side of the auxiliary nozzle discharge port; the collecting bin is fixedly connected to the lower end of the connecting rod, the front end of which is an open structure, and the lower surface of its bottom plate is a flat structure; the bucket is fixedly connected to the edge of the bottom plate of the open end of the collecting bin, and its lower surface is flush with the lower surface of the bottom plate of the collecting bin; the impeller motor is located at the rear side of the bucket and fixedly connected to the bottom plate of the collecting bin; the impeller is arranged above the impeller motor, and its rotating shaft is fixedly connected to the output shaft of the impeller motor;

[0013] The solenoid valve is fixedly installed in the feed port of the auxiliary nozzle and is used to control the opening and closing of the feed port of the auxiliary nozzle;

[0014] The display screen is arranged outside the extrusion barrel and mounted on the 3D printer frame;

[0015] The controller is fixedly installed on the outside of the extrusion barrel and is respectively connected to the main screw pump, the auxiliary screw pump, the automatic distance meter A, the automatic distance meter B, the solenoid valve, the impeller motor and the display screen through cables.

[0016] Furthermore, in order to facilitate the operator to visually observe the internal conditions of the aggregate bin, an observation window is opened on the rear side panel of the aggregate bin, and a transparent observation panel is installed in the observation window.

[0017] Furthermore, the connecting rod is vertically mounted, with its upper end fixedly connected to the extrusion barrel via bolts. The residual material collection mechanism also includes a window handle fixedly connected to the lower portion of the rear end of the observation panel of the collection bin. The window handle allows for easy removal and insertion of the observation panel into the observation window.

[0018] Furthermore, in order to ensure that the measurement signal is not interfered with and to ensure the accuracy of the measurement structure, the position of the automatic rangefinder A is tangent to the outer contour of the main nozzle, the position of the automatic rangefinder B is tangent to the outer contour of the auxiliary nozzle, and the sensing surface heights of the automatic rangefinder A and the automatic rangefinder B are consistent.

[0019] Furthermore, in order to ensure an ideal repair effect and avoid excessive material waste during the repair process, the size of the rear cavity is smaller than that of the front cavity, and the size of the auxiliary nozzle is smaller than that of the main nozzle.

[0020] In the present invention, a partition is used to separate the inner cavity of the extrusion barrel into a front cavity and a rear cavity. The front cavity can be used as a material storage cavity for printing operations, and at the same time, the rear cavity can be used as a material storage cavity for repair operations. A main stirring screw with a spiral conveying blade fixedly connected to the outside is set in the front cavity, and the main stirring screw is connected to the main screw pump. The main screw pump can be used to drive the main stirring screw to rotate, and then the spiral conveying blade can be driven to rotate. In this way, the material in the front cavity can be transported downward and extruded through the main nozzle installed at the lower end of the front cavity, thereby realizing continuous supply of materials during the printing operation. By setting up the automatic rangefinder A, it is convenient to collect the distance signal A on the rear side of the main nozzle, and then it is convenient for the controller to obtain the distance S1 from the automatic rangefinder A to the printing model. An auxiliary stirring screw with an externally fixed spiral conveying blade is provided in the rear cavity, and the auxiliary stirring screw is connected to the auxiliary screw pump. The auxiliary screw pump can be used to drive the auxiliary stirring screw to rotate, which in turn can drive the spiral conveying blade to rotate. In this way, the material in the rear cavity can be transported downward and extruded through the auxiliary nozzle installed at the lower end of the front cavity, thereby achieving continuous supply of material during the repair operation. By setting up the automatic rangefinder B, it is convenient to collect the distance measurement signal B of the printed model behind the auxiliary nozzle, and then it is convenient for the controller to obtain the distance S2 from the automatic rangefinder B to the printed model. By setting up the solenoid valve, it is convenient to control the opening and closing action of the auxiliary nozzle feed port, so that the repair operation can be controlled as needed. At the same time, the start and stop of the repair operation can be conveniently controlled by the synchronous action of the solenoid valve and the auxiliary screw pump. A residual material collection mechanism is installed on the lower rear side of the auxiliary nozzle, and the front end of the collection bin is open. A bucket is installed at the edge of the base plate at the open end. This bucket can be used to collect material that exceeds the layer height during normal printing. It can also be used to collect material that exceeds the layer height during repair. In addition, because the shovel head and the lower surface of the collection bin base are coplanar, the printed area can be smoothed during the collection process, achieving a leveling effect. The display screen allows the operator to quickly monitor the distance between the automatic rangefinder and the printed model and also provides timely notifications. This device not only combines the advantages of 3D concrete printing for rock formation printing of similar models in mines, but also allows for online detection of incomplete internal defects during the printing process and the repair of defective areas. The present invention effectively improves the accuracy of similar model printing, accurately reproducing the actual conditions and mechanical properties of the model prototype, and ensuring greater reliability in subsequent testing.

[0021] The present invention also provides a method for detecting and repairing internal defects of a 3D printed concrete mine-like model, which uses a device for detecting and repairing internal defects of a 3D printed concrete mine-like model, including the following steps:

[0022] Step 1: Set the layer height h according to the model's slicing conditions and printing parameters;

[0023] Step 2: Pour the prepared concrete material into the front cavity and the rear cavity from the inlet ports at the upper ends thereof until the front cavity and the rear cavity are filled.

[0024] Step 3: Use the transmission system in the 3D printer to drive the extruder barrel to move at a constant speed along the predetermined printing path and direction. Synchronously, the controller controls the main screw pump to start working, keeps the auxiliary screw pump in a stopped state, and keeps the solenoid valve in a closed state. The main screw pump is used to drive the main stirring screw to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle to perform a printing operation of a similar model. During this process, the distance signal A from the printed model is collected in real time by the automatic distance meter A and sent to the controller; the distance signal B from the printed model is collected in real time by the automatic distance meter B and sent to the controller; the controller obtains the distance S1 from the automatic distance meter A to the printed model and the distance S2 from the automatic distance meter B to the printed model based on the distance signal A and the distance signal B, and sends the distance S1 and the distance S2 to the display screen for real-time display. At the same time, the difference between the distance S1 and the distance S2 is compared to determine whether there is a defect.

[0025] When S1-S2 is less than 0.5h, there is no defect that needs to be repaired in the area measured by the automatic distance meter B. The transmission system in the 3D printer continues to drive the extruder barrel to move at a constant speed along the predetermined printing path and direction. Synchronously, the main screw pump is kept in the working state, the auxiliary screw pump is kept in the stopped state, and the solenoid valve is kept in the closed state. The main screw pump continues to drive the main stirring screw to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle. The printing operation continues along the predetermined printing path and direction.

[0026] When S1-S2≥0.5h, there is a defect in the area measured by the automatic distance meter B that needs to be repaired. The defect repair work should be carried out as follows:

[0027] S1: Use the transmission system in the 3D printer to stop the extrusion barrel and record the defect location;

[0028] S2: The transmission system in the 3D printer is used to drive the extrusion barrel to move in the opposite direction of the previously predetermined printing path. During the reverse movement of the extrusion barrel, the controller controls the main screw pump to stop, controls the auxiliary screw pump to start working, and controls the solenoid valve to open, so that the main nozzle stops extruding the material. At the same time, the auxiliary screw pump is used to drive the auxiliary stirring screw to rotate, and the material in the rear cavity is transported downward and extruded through a smaller auxiliary nozzle to repair the defective position. When the automatic rangefinder A moves to the defective position, the transmission system in the 3D printer is used to stop the extrusion barrel, and the controller controls the auxiliary screw pump to stop working, controls the solenoid valve to close, and keeps the main screw pump in the shutdown state;

[0029] S3: The transmission system in the 3D printer is used to drive the extrusion barrel to reset forward. During the forward reset movement, the controller controls the impeller motor to start working, and the bucket in the residual material collection mechanism is used to collect and smooth the overflowed layer due to repair, and the impeller is used to transport the material collected by the bucket to the aggregate bin. When the automatic rangefinder B moves back to the recorded defect position, the transmission system in the 3D printer is used to stop the extrusion barrel, and the controller is used to control the impeller motor to stop working. The difference between the distance S1 and the distance S2 is compared to determine whether the defect is repaired successfully. If S1-S2 ≥ 0.5h, the repair fails. After the repair fails, the controller sends the recorded defect position to the display screen, which displays the defect position in real time and gives a reminder message that manual intervention is required. Then, step four is executed. If S1-S2 < 0.5h, the repair is successful, and then step five is executed.

[0030] Step 4: Manually control the transmission system in the 3D printer to move the extruder barrel to the defective location, keep the main screw pump in the stopped state, manually control the solenoid valve to open, and manually control the auxiliary screw pump to start working. Use the auxiliary screw pump to drive the auxiliary stirring screw to rotate, and transport the material in the rear cavity downward and extrude it through a smaller auxiliary nozzle to repair the defective location through manual operation;

[0031] After the repair work is completed, the transmission system in the 3D printer is used to drive the extrusion barrel to reset forward. During the forward reset movement, the controller controls the impeller motor to start working, and the bucket in the residual material collection mechanism is used to collect and smooth the overflowed layer during the repair. The impeller is used to transport the material collected by the bucket to the collection bin. When the automatic distance meter B moves back to the recorded defect position, the transmission system in the 3D printer is used to stop the extrusion barrel from moving, and the controller controls the impeller motor to stop working.

[0032] Step 5: Use the transmission system in the 3D printer to drive the extruder barrel to continue moving at a constant speed along the predetermined printing path and direction. Synchronously, the controller controls the main screw pump to start, the auxiliary screw pump to stop, and the solenoid valve to close. The main screw pump is used to drive the main stirring screw to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle. Continue to print similar models according to the predetermined printing path and direction until the printing job is completed.

[0033] Furthermore, in order to avoid excessive material in the aggregate bin and affect the subsequent material collection operation, in steps three and four, the material inside the aggregate bin is observed through the observation board to observe whether it is full. When the material is full, the machine is stopped to clean the material.

[0034] In this method, during normal printing, an automatic distance meter A collects distance signal A from the area immediately after printing by the main nozzle. Simultaneously, an automatic distance meter B collects distance signal B from the area behind the auxiliary nozzle. Based on distance signals A and B, the distance difference between the area detected by automatic distance meter A and the area detected by automatic distance meter B is calculated. The relationship between this distance difference and the set layer height is then used to determine whether a defect exists in the area detected by automatic distance meter B. If a defect does occur, repair work can be performed automatically at the defect location. During the repair process, the relationship between the distance difference between the two detected areas and the set layer height is further used to determine whether the repair was successful. If the repair is unsuccessful, a manual intervention reminder is issued to prompt personnel to manually intervene, ensuring timely and reliable repairs. If the repair is successful, normal printing can resume. Since the defect location is recorded during the defect detection process, subsequent test results of similar models can be analyzed using the recorded internal defect location as a reference. During the resetting process after defect repair is completed, the bucket in the residual material collection mechanism collects the material that exceeds the layer height, and the bottom plate of the collection bin and the bottom surface of the bucket are used to smooth the repaired area, thus effectively ensuring the repair effect of the repaired area. The present invention has simple steps and low implementation costs. It can synchronously detect internal defects during the printing process, and at the same time, it can effectively repair the defective area in a relatively automated manner, and can ensure that the repaired effect meets the use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the present invention;

[0036] Figure 2 It is a structural schematic diagram of the residual material collecting mechanism in the present invention.

[0037] In the figure: 1-1, extrusion barrel; 1-2, main stirring screw; 1-3, auxiliary stirring screw; 1-4, main nozzle; 1-5, automatic distance meter A; 1-6, automatic distance meter B; 1-7, display screen; 1-8, auxiliary nozzle; 1-9, main screw pump; 1-10, auxiliary screw pump; 1-11, solenoid valve; 1-12, controller; 1-13, cable; 1-14, residual material collection mechanism; 1-15, material, 1-16, partition; 2-1, bucket; 2-2, impeller; 2-3, impeller motor; 2-4, collection bin; 2-5, observation window; 2-6, window handle; 2-7, connecting rod. DETAILED DESCRIPTION

[0038] The present invention will be further described below.

[0039] like Figure 1 and Figure 2 As shown, the present invention provides a 3D printed concrete mine similar model internal defect detection and repair device, including an extrusion barrel 1-1, a main screw pump 1-9, a main stirring screw 1-2, a main nozzle 1-4, an automatic distance meter A1-5, a secondary screw pump 1-10, a secondary stirring screw 1-3, an auxiliary nozzle 1-8, an automatic distance meter B1-6, a residual material collection mechanism 1-14, a solenoid valve 1-11, a display screen 1-7 and a controller 1-12;

[0040] A vertically extending partition 1-16 is provided at the rear middle portion of the extrusion barrel 1-1; the partition 1-16 divides the inner cavity of the extrusion barrel 1-1 into a front cavity and a rear cavity;

[0041] The main screw pump 1-9 is fixedly arranged above the center of the front cavity; the main stirring screw 1-2 is rotatably arranged at the center inside the front cavity, and a spiral conveying blade is fixedly connected to its outside, and its upper end is fixedly connected to the output shaft of the main screw pump 1-9; the main nozzle 1-4 is funnel-shaped, and the size of its feed port is adapted to the size of the front cavity. The main nozzle 1-4 is fixedly connected to the front side of the lower end of the extrusion barrel 1-1, and its feed port is connected to the lower end of the front cavity;

[0042] The automatic distance meter A1-5 is located at the rear side of the main nozzle 1-4 and is fixedly installed on the outside of the main nozzle 1-4, and is used to collect the distance signal A from the automatic distance meter A1-5 to the printed model in real time and send it to the controller 1-12 in real time;

[0043] The auxiliary screw pump 1-10 is fixedly arranged above the center of the rear cavity; the auxiliary stirring screw 1-3 is rotatably arranged at the center inside the rear cavity, and a spiral conveying blade is fixedly connected to its outside, and its upper end is fixedly connected to the output shaft of the auxiliary screw pump 1-10; the auxiliary nozzle 1-8 is funnel-shaped, and the size of its feed port is adapted to the size of the rear cavity; the auxiliary nozzle 1-8 is located on the rear side of the main nozzle 1-4 and is fixedly connected to the rear side of the lower end of the extrusion barrel 1-1, and its feed port is connected to the rear cavity, and the height of its discharge port is the same as that of the discharge port of the main nozzle 1-4;

[0044] The automatic distance meter B1-6 is located at the rear side of the auxiliary nozzle 1-8 and is fixedly installed on the outside of the auxiliary nozzle 1-8, and is used to collect the distance signal B from the automatic distance meter B1-6 to the printed model in real time and send it to the controller 1-12 in real time;

[0045] The residual material collecting mechanism 1-14 is arranged at the lower rear side of the auxiliary nozzle 1-8 and at the rear side of the automatic rangefinder B1-6, and includes a connecting rod 2-7, a collecting bin 2-4, a bucket 2-1, an impeller motor 2-3 and an impeller 2-2; the upper end of the connecting rod 2-7 is fixedly connected to the rear end of the extrusion barrel 1-1, and the lower end thereof extends to the lower side of the discharge port of the auxiliary nozzle 1-8; the collecting bin 2-4 is fixedly connected to the lower end of the connecting rod 2-7, the front end of which is an open structure, and the lower surface of its bottom plate is a flat structure; the bucket 2-1 is fixedly connected to the edge of the bottom plate of the open end of the collecting bin 2-4, and its lower surface is flush with the lower surface of the bottom plate of the collecting bin 2-4, and is used to collect materials that exceed the layer height during the process of moving forward; The impeller motor 2-3 is located at the rear side of the bucket 2-1 and is fixedly connected to the bottom plate of the collecting bin 2-4. As a preferred embodiment, the impeller motor 2-3 is a micro motor with a small axial height, so as not to affect the passability of the material; the impeller 2-2 is arranged above the impeller motor 2-3, and its rotating shaft is fixedly connected to the output shaft of the impeller motor 2-3. Under the drive of the impeller motor 2-3, the impeller 2-2 transports the material collected by the bucket 2-1 to the rear space of the collecting bin 2-4, so that the collecting bin 2-4 can collect more material; as a further preferred embodiment, the outer cover of the impeller motor 2-3 is provided with a cover body, and the output shaft of the impeller motor 2-3 passes through the reserved hole at the upper end of the cover body, and the impeller 2-2 is arranged above the cover body;

[0046] The solenoid valve 1-11 is fixedly installed in the feed port of the auxiliary nozzle 1-8 and is used to control the opening and closing of the feed port of the auxiliary nozzle 1-8;

[0047] The display screen 1-7 is arranged outside the extrusion barrel 1-1 and mounted on the 3D printer frame; the display screen 1-7 is used to display the data sent by the controller 1-12 in real time and serves as a human-computer interaction interface for sending the operator's control instructions to the controller 1-12;

[0048] As a preference, the controller 1-12 is a PLC controller, which is fixedly mounted on the outside of the extrusion barrel 1-1 and is connected to the main screw pump 1-9, the auxiliary screw pump 1-10, the automatic distance meter A1-5, the automatic distance meter B1-6, the solenoid valve 1-11, the impeller motor 2-3 and the display screen 1-7 through the cable 1-13. The controller 1-12 is used to obtain the distance S1 between the automatic distance meter A1-5 and the printed model and the distance S2 between the automatic distance meter B1-6 and the printed model based on the distance signal A and the distance signal B, and to send the distance S1 and the distance S2 to the display screen 1-7 for real-time display. At the same time, it is used to determine whether there is a defect by comparing the difference between the distance S1 and the distance S2, and to control the start and stop of the main screw pump 1-9 and the impeller motor 2-3, and to synchronously control the auxiliary screw pump 1-10 and the solenoid valve 1-11, that is, when the auxiliary screw pump 1-10 is controlled to start working, the solenoid valve 1-11 is synchronously controlled to open, and when the auxiliary screw pump 1-10 is controlled to stop working, the solenoid valve 1-11 is synchronously controlled to close;

[0049] In order to facilitate the operator to visually observe the internal conditions of the aggregate bin, an observation window 2-5 is opened on the rear side panel of the aggregate bin 2-4, and a transparent observation panel is installed in the observation window 2-5.

[0050] The connecting rod 2-7 is vertically arranged, and its upper end is fixedly connected to the extrusion barrel 1-1 by a bolt. The residual material collection mechanism 1-14 also includes a window handle 2-6, which is fixedly connected to the lower portion of the rear end of the observation plate of the collection bin 2-4. The window handle can be easily removed from the observation window and can also be easily inserted into the observation window.

[0051] In order to ensure that the measurement signal is not interfered with and to ensure the accuracy of the measurement structure, the position of the automatic rangefinder A1-5 is tangent to the outer contour of the main nozzle 1-4, the position of the automatic rangefinder B1-6 is tangent to the outer contour of the auxiliary nozzle 1-8, and the sensing surface heights of the automatic rangefinder A1-5 and the automatic rangefinder B1-6 are consistent.

[0052] Both the automatic rangefinder A1-5 and the automatic rangefinder B1-6 use the principle of infrared sensor distance measurement. The internal micro-infrared transmitter emits infrared light, which is reflected back when it hits a reflective object and then received by the internal receiver. The measured distance can be calculated through the distance measuring element based on the time T from the emission to the reception of the infrared light and the propagation speed V of the infrared light.

[0053] In order to ensure an ideal repair effect and to avoid excessive material waste during the repair process, the size of the rear cavity is smaller than that of the front cavity, and the size of the auxiliary nozzle 1-8 is smaller than that of the main nozzle 1-4; as a preferred embodiment, the aperture of the main nozzle 1-4 discharge port is 20 mm, and the aperture of the auxiliary nozzle 1-8 discharge port is 10 mm.

[0054] In the present invention, a partition is used to separate the inner cavity of the extrusion barrel into a front cavity and a rear cavity. The front cavity can be used as a material storage cavity for printing operations, and at the same time, the rear cavity can be used as a material storage cavity for repair operations. A main stirring screw with a spiral conveying blade fixedly connected to the outside is set in the front cavity, and the main stirring screw is connected to the main screw pump. The main screw pump can be used to drive the main stirring screw to rotate, and then the spiral conveying blade can be driven to rotate. In this way, the material in the front cavity can be transported downward and extruded through the main nozzle installed at the lower end of the front cavity, thereby realizing continuous supply of materials during the printing operation. By setting up the automatic rangefinder A, it is convenient to collect the distance signal A on the rear side of the main nozzle, and then it is convenient for the controller to obtain the distance S1 from the automatic rangefinder A to the printing model. An auxiliary stirring screw with an externally fixed spiral conveying blade is provided in the rear cavity, and the auxiliary stirring screw is connected to the auxiliary screw pump. The auxiliary screw pump can be used to drive the auxiliary stirring screw to rotate, which in turn can drive the spiral conveying blade to rotate. In this way, the material in the rear cavity can be transported downward and extruded through the auxiliary nozzle installed at the lower end of the front cavity, thereby achieving continuous supply of material during the repair operation. By setting up the automatic rangefinder B, it is convenient to collect the distance measurement signal B of the printed model behind the auxiliary nozzle, and then it is convenient for the controller to obtain the distance S2 from the automatic rangefinder B to the printed model. By setting up the solenoid valve, it is convenient to control the opening and closing action of the auxiliary nozzle feed port, so that the repair operation can be controlled as needed. At the same time, the start and stop of the repair operation can be conveniently controlled by the synchronous action of the solenoid valve and the auxiliary screw pump. A residual material collection mechanism is installed on the lower rear side of the auxiliary nozzle, and the front end of the collection bin is open. A bucket is installed at the edge of the base plate at the open end. This bucket can be used to collect material that exceeds the layer height during normal printing. It can also be used to collect material that exceeds the layer height during repair. In addition, because the shovel head and the lower surface of the collection bin base are coplanar, the printed area can be smoothed during the collection process, achieving a leveling effect. The display screen allows the operator to quickly monitor the distance between the automatic rangefinder and the printed model and also provides timely notifications. This device not only combines the advantages of 3D concrete printing for rock formation printing of similar models in mines, but also allows for online detection of incomplete internal defects during the printing process and the repair of defective areas. The present invention effectively improves the accuracy of similar model printing, accurately reproducing the actual conditions and mechanical properties of the model prototype, and ensuring greater reliability in subsequent testing.

[0055] The present invention also provides a method for detecting and repairing internal defects of a 3D printed concrete mine-like model, which uses a device for detecting and repairing internal defects of a 3D printed concrete mine-like model, including the following steps:

[0056] Step 1: Set the layer height h according to the model's slicing conditions and printing parameters;

[0057] Step 2: Pour the prepared concrete material into the front cavity and the rear cavity from the inlet ports at the upper ends thereof until the front cavity and the rear cavity are filled.

[0058] Step 3: Use the transmission system in the 3D printer to drive the extruder barrel 1-1 to move at a constant speed along the predetermined printing path and direction. Synchronously, the controller 1-12 controls the main screw pump 1-9 to start working, keeps the auxiliary screw pump 1-10 in a stopped state, and keeps the solenoid valve 1-11 in a closed state. The main screw pump 1-9 drives the main stirring screw 1-2 to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle 1-4 to perform a similar model printing operation. During this process, the distance between the printing and the material is collected in real time by the automatic rangefinder A1-5. The controller 1-12 receives a distance signal A from the printed model and sends it to the controller 1-12; the automatic distance meter B1-6 collects a distance signal B from the printed model in real time and sends it to the controller 1-12; the controller 1-12 obtains the distance S1 from the automatic distance meter A1-5 to the printed model and the distance S2 from the automatic distance meter B1-6 to the printed model based on the distance signal A and the distance signal B, and sends the distance S1 and the distance S2 to the display screen 1-7 for real-time display. At the same time, the difference between the distance S1 and the distance S2 is compared to determine whether there is a defect;

[0059] When S1-S2 is less than 0.5h, there are no defects that need to be repaired in the area measured by the automatic distance meter B1-6, and the transmission system in the 3D printer continues to drive the extruder barrel 1-1 to move at a constant speed along the predetermined printing path and direction. Synchronously, the main screw pump 1-9 continues to be kept in the working state, the auxiliary screw pump 1-10 continues to be kept in the stopped state, and the solenoid valve 1-11 continues to be kept in the closed state. The main screw pump 1-9 continues to drive the main stirring screw 1-2 to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle 1-4, and the printing operation continues along the predetermined printing path and direction;

[0060] When S1-S2≥0.5h, there is a defect in the area measured by the automatic distance meter B1-6 that needs to be repaired. The defect repair work should be carried out as follows:

[0061] S1: Using the transmission system in the 3D printer to stop the extrusion barrel 1-1 from moving, and at the same time, record the defect location;

[0062] S2: The transmission system in the 3D printer is used to drive the extrusion barrel 1-1 to move in the opposite direction of the previously predetermined printing path. During the reverse movement of the extrusion barrel 1-1, the controller 1-12 controls the main screw pump 1-9 to stop, controls the auxiliary screw pump 1-10 to start working, and controls the solenoid valve 1-11 to open, so that the main nozzle 1-4 stops extruding the material. At the same time, the auxiliary screw pump 1-10 is used to drive the auxiliary stirring screw 1-3 to rotate, and the material in the rear cavity is transported downward and extruded through the smaller auxiliary nozzle 1-8 to repair the defective position. When the automatic distance meter A1-5 moves to the defective position, the transmission system in the 3D printer is used to stop the extrusion barrel 1-1, and the controller 1-12 controls the auxiliary screw pump 1-10 to stop working, controls the solenoid valve 1-11 to close, and keeps the main screw pump 1-9 in the shutdown state;

[0063] S3: The transmission system in the 3D printer is used to drive the extrusion barrel 1-1 to reset forward. During the forward reset process, the controller 1-12 controls the impeller motor 2-3 to start working, and the bucket 2-1 in the residual material collection mechanism 1-14 is used to collect and smooth the overflowed layer during the repair. The impeller 2-2 is used to transport the material collected by the bucket 2-1 to the collection bin 2-4. When the automatic distance meter B1-6 moves back to the recorded defect position, the transmission system in the 3D printer is used to stop the extrusion barrel 1-1. Stop moving, use the controller 1-12 to control the impeller motor 2-3 to stop working, and judge whether the defect is repaired successfully by comparing the difference between the distance S1 and the distance S2. If S1-S2≥0.5h, the repair fails. After the repair fails, the controller 1-12 sends the recorded defect position and manual intervention reminder information to the display screen 1-7. The display screen 1-7 displays the defect position in real time and gives a reminder message that manual intervention is required. Then, step 4 is executed. If S1-S2<0.5h, the repair is successful, and then step 5 is executed;

[0064] Step 4: Manually control the transmission system in the 3D printer to move the extruder barrel 1-1 to the defective position, keep the main screw pump 1-9 in a stopped state, manually control the solenoid valve 1-11 to open, and manually control the auxiliary screw pump 1-10 to start working. The auxiliary screw pump 1-10 drives the auxiliary stirring screw 1-3 to rotate, and the material in the rear cavity is transported downward and extruded through the smaller auxiliary nozzle 1-8, so as to repair the defective position through manual operation;

[0065] After the repair work is completed, the transmission system in the 3D printer is used to drive the extrusion barrel 1-1 to reset forward. During the forward reset movement, the controller 1-12 is used to control the impeller motor 2-3 to start working, and the bucket 2-1 in the residual material collection mechanism 1-14 is used to collect and smooth the overflowed layer during the repair, and the impeller 2-2 is used to transport the material collected by the bucket 2-1 to the collecting bin 2-4. When the automatic distance meter B1-6 moves back to the recorded defect position, the transmission system in the 3D printer is used to stop the extrusion barrel 1-1, and the controller 1-12 is used to control the impeller motor 2-3 to stop working;

[0066] Step 5: Use the transmission system in the 3D printer to drive the extruder barrel 1-1 to continue moving at a constant speed along the predetermined printing path and direction. Synchronously, the controller 1-12 controls the main screw pump 1-9 to start working, controls the auxiliary screw pump 1-10 to stop, and controls the solenoid valve 1-11 to close. The main screw pump 1-9 is used to drive the main stirring screw 1-2 to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle 1-4. Continue to print similar models according to the predetermined printing path and direction until the printing job is completed.

[0067] To prevent excessive material in the collection bin from affecting subsequent material collection operations, in steps 3 and 4, the observation panel is used to observe whether the collection bin 2-4 is full. When the material is full, the machine is stopped for material cleaning. During cleaning, the observation panel can be removed from the observation window 2-5 using the window handle 2-6, thereby facilitating and quickly completing material cleaning operations.

[0068] In this method, during normal printing, an automatic distance meter A collects distance signal A from the area immediately after printing by the main nozzle. Simultaneously, an automatic distance meter B collects distance signal B from the area behind the auxiliary nozzle. Based on distance signals A and B, the distance difference between the area detected by automatic distance meter A and the area detected by automatic distance meter B is calculated. The relationship between this distance difference and the set layer height is then used to determine whether a defect exists in the area detected by automatic distance meter B. If a defect does occur, repair work can be performed automatically at the defect location. During the repair process, the relationship between the distance difference between the two detected areas and the set layer height is further used to determine whether the repair was successful. If the repair is unsuccessful, a manual intervention reminder is issued to prompt personnel to manually intervene, ensuring timely and reliable repairs. If the repair is successful, normal printing can resume. Since the defect location is recorded during the defect detection process, subsequent test results of similar models can be analyzed using the recorded internal defect location as a reference. During the resetting process after defect repair is completed, the bucket in the residual material collection mechanism collects the material that exceeds the layer height, and the bottom plate of the collection bin and the bottom surface of the bucket are used to smooth the repaired area, thus effectively ensuring the repair effect of the repaired area. The present invention has simple steps and low implementation costs. It can synchronously detect internal defects during the printing process, and at the same time, it can effectively repair the defective area in a relatively automated manner, and can ensure that the repaired effect meets the use requirements.

Claims

1. A 3D printed concrete mine similarity model internal defect detection and repair device, comprising an extrusion barrel (1-1), a main screw pump (1-9), a main stirring screw (1-2), a main nozzle (1-4) and an automatic distance meter A (1-5); characterized in that: It also includes an auxiliary screw pump (1-10), an auxiliary stirring screw (1-3), an auxiliary nozzle (1-8), an automatic distance meter B (1-6), a residual material collecting mechanism (1-14), a solenoid valve (1-11), a display screen (1-7) and a controller (1-12); A vertically extending partition (1-16) is provided at the rear middle portion of the extrusion barrel (1-1); the partition (1-16) divides the inner cavity of the extrusion barrel (1-1) into a front cavity and a rear cavity; The main screw pump (1-9) is fixedly arranged above the center of the front cavity; the main stirring screw (1-2) is rotatably arranged at the center inside the front cavity, and its exterior is fixedly connected to a spiral conveying blade, and its upper end is fixedly connected to the output shaft of the main screw pump (1-9); the main nozzle (1-4) is funnel-shaped, and the size of its feed port is adapted to the size of the front cavity. The main nozzle (1-4) is fixedly connected to the front side of the lower end of the extrusion barrel (1-1), and its feed port is connected to the lower end of the front cavity; The automatic distance meter A (1-5) is located at the rear side of the main nozzle (1-4) and is fixedly installed on the outside of the main nozzle (1-4); The auxiliary screw pump (1-10) is fixedly arranged above the center of the rear cavity; the auxiliary stirring screw (1-3) is rotatably arranged at the center inside the rear cavity, and its exterior is fixedly connected to a spiral conveying blade, and its upper end is fixedly connected to the output shaft of the auxiliary screw pump (1-10); the auxiliary nozzle (1-8) is funnel-shaped, and the size of its feed port is adapted to the size of the rear cavity; the auxiliary nozzle (1-8) is fixedly connected to the rear side of the lower end of the extrusion barrel (1-1), and its feed port is connected to the rear cavity, and the height of its discharge port is the same as that of the discharge port of the main nozzle (1-4); The automatic distance meter B (1-6) is located at the rear side of the auxiliary nozzle (1-8) and is fixedly mounted on the outside of the auxiliary nozzle (1-8); The residual material collecting mechanism (1-14) is arranged below the rear side of the auxiliary nozzle (1-8), and comprises a connecting rod (2-7), a collecting bin (2-4), a bucket (2-1), an impeller motor (2-3) and an impeller (2-2); the upper end of the connecting rod (2-7) is fixedly connected to the rear end of the extrusion barrel (1-1), and the lower end thereof extends below the discharge port of the auxiliary nozzle (1-8); the collecting bin (2-4) is fixedly connected to the lower end of the connecting rod (2-7), and the front end thereof is open. The structure has a bottom surface of a flat structure; the bucket (2-1) is fixedly connected to the bottom edge of the open end of the collecting bin (2-4), and its bottom surface is flush with the bottom surface of the bottom of the collecting bin (2-4); the impeller motor (2-3) is located at the rear side of the bucket (2-1) and is fixedly connected to the bottom of the collecting bin (2-4); the impeller (2-2) is arranged above the impeller motor (2-3), and its rotating shaft is fixedly connected to the output shaft of the impeller motor (2-3); The solenoid valve (1-11) is fixedly installed in the feed port of the auxiliary nozzle (1-8) and is used to control the opening and closing of the feed port of the auxiliary nozzle (1-8); The display screen (1-7) is arranged outside the extrusion barrel (1-1) and is installed on the 3D printer frame; The controller (1-12) is fixedly installed outside the extrusion barrel (1-1) and is respectively connected to the main screw pump (1-9), the auxiliary screw pump (1-10), the automatic distance meter A (1-5), the automatic distance meter B (1-6), the solenoid valve (1-11), the impeller motor (2-3) and the display screen (1-7) through the cable (1-13).

2. The internal defect detection and repair device of a 3D printed concrete mine similarity model according to claim 1 is characterized in that: An observation window (2-5) is provided on the rear side panel of the aggregate bin (2-4), and a transparent observation panel is installed in the observation window (2-5).

3. A 3D printed concrete mine similarity model internal defect detection and repair device according to claim 1 or 2, characterized in that: The connecting rod (2-7) is vertically arranged, and its upper end is fixedly connected to the extrusion barrel (1-1) via a bolt; the residual material collecting mechanism (1-14) further comprises a window handle (2-6), and the window handle (2-6) is fixedly connected to the lower part of the rear end of the observation plate of the collecting bin (2-4).

4. The internal defect detection and repair device of a 3D printed concrete mine similarity model according to claim 3 is characterized in that: The position of the automatic distance meter A (1-5) is tangent to the outer contour of the main nozzle (1-4), the position of the automatic distance meter B (1-6) is tangent to the outer contour of the auxiliary nozzle (1-8), and the sensing surfaces of the automatic distance meter A (1-5) and the automatic distance meter B (1-6) are consistent in height.

5. The device for detecting and repairing internal defects of a 3D printed concrete mine similarity model according to claim 4, characterized in that: The size of the rear cavity is smaller than that of the front cavity, and the size of the auxiliary nozzle (1-8) is smaller than that of the main nozzle (1-4).

6. A method for detecting and repairing internal defects of a 3D printed concrete mine-like model, using the device for detecting and repairing internal defects of a 3D printed concrete mine-like model according to claim 5, characterized in that: The following steps are involved: Step 1: Set the layer height h according to the model's slicing conditions and printing parameters; Step 2: Pour the prepared concrete material into the front cavity and the rear cavity from the inlet ports at the upper ends thereof until the front cavity and the rear cavity are filled. Step 3: Use the transmission system in the 3D printer to drive the extruder barrel (1-1) to move at a constant speed along the predetermined printing path and direction. Synchronously, the controller (1-12) controls the main screw pump (1-9) to start working, keeps the auxiliary screw pump (1-10) in a stopped state, and keeps the solenoid valve (1-11) in a closed state. The main screw pump (1-9) drives the main stirring screw (1-2) to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle (1-4) to perform a printing operation of a similar model. During this process, the distance is collected in real time by the automatic distance meter A (1-5). A distance signal A from the printed model is generated and sent to a controller (1-12); a distance signal B from the printed model is collected in real time by an automatic distance meter B (1-6) and sent to the controller (1-12); the controller (1-12) obtains a distance S1 from the automatic distance meter A (1-5) to the printed model and a distance S2 from the automatic distance meter B (1-6) to the printed model based on the distance signal A and the distance signal B, and sends the distance S1 and the distance S2 to a display screen (1-7) for real-time display. At the same time, the difference between the distance S1 and the distance S2 is compared to determine whether there is a defect. When S1-S2 is less than 0.5h, there are no defects that need to be repaired in the area measured by the automatic distance meter B (1-6), and the transmission system in the 3D printer continues to drive the extruder barrel (1-1) to move at a constant speed along the predetermined printing path and direction. Synchronously, the main screw pump (1-9) continues to be kept in the working state, the auxiliary screw pump (1-10) continues to be kept in the stopped state, and the solenoid valve (1-11) continues to be kept in the closed state. The main screw pump (1-9) continues to drive the main stirring screw (1-2) to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle (1-4), and the printing operation continues along the predetermined printing path and direction. When S1-S2≥0.5h, there is a defect in the area measured by the automatic distance meter B (1-6) that needs to be repaired. The defect repair work should be carried out as follows: S1: Using the transmission system in the 3D printer to stop the extrusion barrel (1-1) from moving, and at the same time, record the defect location; S2: The transmission system in the 3D printer is used to drive the extrusion barrel (1-1) to move in the opposite direction to the previously predetermined printing path. During the reverse movement of the extrusion barrel (1-1), the controller (1-12) controls the main screw pump (1-9) to stop, controls the auxiliary screw pump (1-10) to start working, and controls the solenoid valve (1-11) to open, so that the main nozzle (1-4) stops extruding the material. At the same time, the auxiliary screw pump (1-10) is used to drive the auxiliary stirring screw (1-3) to rotate, so that the material in the rear cavity is transported downward and extruded through the smaller auxiliary nozzle (1-8) to repair the defective position. When the automatic distance meter A (1-5) moves to the defective position, the transmission system in the 3D printer is used to stop the extrusion barrel (1-1), and the controller (1-12) controls the auxiliary screw pump (1-10) to stop working, controls the solenoid valve (1-11) to close, and keeps the main screw pump (1-9) in the shutdown state. S3: The extruder barrel (1-1) is driven to move forward and reset by the transmission system in the 3D printer. During the forward reset movement, the controller (1-12) controls the impeller motor (2-3) to start working, and the bucket (2-1) in the residual material collection mechanism (1-14) is used to collect and smooth the overflowed layer during the repair, and the impeller (2-2) is used to transport the material collected by the bucket (2-1) to the collection bin (2-4). When the automatic distance meter B (1-6) moves back to the recorded defect position, the transmission system in the 3D printer is used to The extruder barrel (1-1) stops moving, and the controller (1-12) controls the impeller motor (2-3) to stop working. The difference between the distance S1 and the distance S2 is compared to determine whether the defect is repaired successfully. If S1-S2 ≥ 0.5h, the repair fails. After the repair fails, the controller (1-12) sends the recorded defect position to the display screen (1-7). The display screen (1-7) displays the defect position in real time and gives a reminder message that manual intervention is required. Then, step four is executed. If S1-S2 < 0.5h, the repair is successful, and then step five is executed. Step 4: Manually control the transmission system in the 3D printer to move the extruder barrel (1-1) to the defective position, keep the main screw pump (1-9) in a stopped state, manually control the solenoid valve (1-11) to open, and manually control the auxiliary screw pump (1-10) to start working, and use the auxiliary screw pump (1-10) to drive the auxiliary stirring screw (1-3) to rotate, so as to transport the material in the rear cavity downward and extrude it through the smaller auxiliary nozzle (1-8), so as to repair the defective position through manual operation; After the repair work is completed, the transmission system in the 3D printer is used to drive the extrusion barrel (1-1) to reset in the forward direction. During the forward reset movement, the controller (1-12) controls the impeller motor (2-3) to start working, the bucket (2-1) in the residual material collection mechanism (1-14) is used to collect and smooth the overflowed layer height during the repair, and the impeller (2-2) is used to transport the material collected by the bucket (2-1) to the collection bin (2-4). When the automatic distance meter B (1-6) moves back to the recorded defect position, the transmission system in the 3D printer is used to stop the extrusion barrel (1-1), and the controller (1-12) is used to control the impeller motor (2-3) to stop working. Step 5: The transmission system in the 3D printer is used to drive the extruder barrel (1-1) to continue to move at a constant speed along the predetermined printing path and direction. Synchronously, the controller (1-12) controls the main screw pump (1-9) to start working, controls the auxiliary screw pump (1-10) to stop working, and controls the solenoid valve (1-11) to close. The main screw pump (1-9) is used to drive the main stirring screw (1-2) to rotate, and the material in the front cavity is transported downward and extruded through the main nozzle (1-4). The printing operation of similar models continues according to the predetermined printing path and direction until the printing operation is completed.

7. A method for detecting and repairing internal defects of a 3D printed concrete mine similarity model according to claim 6, characterized in that: In step 3 and step 4, the observation panel is used to observe whether the material inside the collecting bin (2-4) is full. When the material is full, the machine is stopped to clean the material.

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