3D printer powder cleaning system based on PLC control

Abstract

The invention is suitable for the field of industrial-grade powder bed melting 3D printing, and provides a PLC control-based 3D printer powder cleaning system which comprises a PLC, a transmission mechanism, a cleaning device, a collecting device, a detection assembly and a protective shell, the PLC is electrically connected with the transmission mechanism and the detection assembly, the transmission mechanism is in transmission connection with the cleaning device to drive the cleaning device to move, the cleaning device corresponds to the collecting device, and the protective shell covers the outer side of the core component; according to the automatic powder cleaning device, state data of powder in the printer is fed back through the detection assembly, the PLC outputs a control signal according to a preset program to regulate and control operation of the transmission mechanism and the cleaning device, automatic powder cleaning and collecting are achieved, the problems that traditional cleaning is low in efficiency, poor in effect and insufficient in safety are solved, the cleaning requirements of different printing scenes can be accurately met, and the cleaning efficiency is improved. And the powder recycling rate and the operation safety are improved.

Description

Technical Field

[0001] This invention belongs to the field of industrial-grade powder bed fusion 3D printing, and particularly relates to a powder cleaning system for 3D printers based on PLC control. Background Technology

[0002] Currently, 3D printing technologies (such as Selective Laser Sintering (SLS), Selective Laser Melting (SLM), and Multi-Jet Fusion (MJF)) are widely used in aerospace, automotive manufacturing, and medical device industries. Among these, powder bed fusion 3D printing technology requires powder as the forming medium. After printing, a large amount of unformed powder remains in the forming cylinder and material cylinder. If not cleaned in time, this can easily damage the electronic components of the equipment and affect the accuracy of subsequent printing.

[0003] Existing cleaning methods have significant drawbacks: First, they rely on manual or semi-automatic operation, requiring operators to open equipment doors and use shovels and brushes to clean or tilt the material cylinder to transfer powder. This not only interrupts the automated process and reduces equipment uptime, but also causes dust pollution due to powder scattering, damaging the respiratory system of operators. Furthermore, flammable and explosive powders (such as titanium and aluminum powders) can easily cause safety accidents. Second, some improvement solutions (such as screw conveyors and simple negative pressure powder suction devices) have limitations. Screw conveyors are difficult to clean for easily adhering powders and are prone to jamming. Negative pressure powder suction devices lack precise control, which can easily lead to incomplete recovery or pipe blockage, and still cannot prevent dust from escaping. Therefore, a PLC-controlled 3D printer powder cleaning system is needed to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a PLC-controlled 3D printer powder cleaning system to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A PLC-controlled powder cleaning system for 3D printers includes a material cylinder, a sealing cover, a vacuum generator, a dust filter, a pneumatic vacuum breaking device, a PLC controller, and a sensor group. The feed cylinder is used to hold the remaining powder after printing is completed; The sealing cover is movably disposed at the opening of the material cylinder, and its driving mechanism is a cylinder or an electric push rod. The vacuum generating device is connected to the internal cavity of the material cylinder through the first pipeline, and a vacuum pump or a venturi tube vacuum generator can be selected. The dust filtration device is installed on the first pipeline and located between the vacuum generator and the material cylinder. It is a high-efficiency air filter or a bag filter. The pneumatic vacuum breaking device is a normally closed solenoid valve, which is connected to the internal cavity of the material cylinder through a second pipeline and is also connected to a gas source that provides clean and dry gas. The PLC controller is electrically connected to the drive mechanism of the sealing cover, the vacuum generator, and the pneumatic vacuum breaking device, respectively. The sensor group is electrically connected to the PLC controller and includes a pressure sensor for detecting the vacuum level inside the material cylinder and a position sensor for detecting the status of the sealing cover.

[0006] In a further technical solution, the pressure sensor is installed inside the material cylinder or on a pipeline connected to the material cylinder, and can feed back the vacuum signal inside the material cylinder to the PLC controller in real time.

[0007] In a further technical solution, the position sensor is a normally open PNP sensor, which can detect the open or closed state of the sealing cover and transmit the status signal to the PLC controller.

[0008] In a further technical solution, the PLC controller can receive the sealing cover closing signal from the position sensor, thereby activating the vacuum generator; When the pressure sensor detects that the vacuum level has reached the first preset threshold, the PLC controller controls the vacuum generator to stop working.

[0009] In a further technical solution, the PLC controller can maintain the vacuum state of the material cylinder for a preset time after the vacuum generator stops working, or control the pneumatic vacuum breaking device to inject gas into the material cylinder when it receives the powder collection completion instruction.

[0010] A further technical solution is that when the pressure sensor detects that the air pressure inside the material cylinder has returned to the second preset threshold (normal pressure), the PLC controller controls the pneumatic vacuum breaking device to stop working and drives the drive mechanism of the sealing cover to open the sealing cover.

[0011] In a further technical solution, the PLC controller controls a solenoid valve or relay to drive the drive mechanism of the sealing cover, thereby realizing the opening and closing of the sealing cover.

[0012] In a further technical solution, when the vacuum generating device is working, the gas drawn from the material cylinder flows through the dust filter device, the powder particles carried in the gas are filtered out, and the clean gas can be discharged or enter the vacuum generating device.

[0013] In a further technical solution, the input terminal of the PLC controller is connected to a start button, a stop button, and an emergency stop button, and the output terminal of the PLC controller is connected to the contactor coil of the vacuum pump, a normally closed solenoid valve, the control solenoid valve of the cylinder, a fault indicator light, and a running indicator light.

[0014] Compared with the prior art, the beneficial effects of the present invention are: This invention, by setting up an intelligent control core consisting of a PLC controller and a sensor group (pressure sensor, position sensor), and matching it with an automated drive mechanism (cylinder or electric push rod) for the sealing cover, achieves fully automated control of the entire process from sealing cover closing, vacuuming, vacuum maintenance to vacuum breaking and cover opening. It eliminates the need for manual opening of the cover for cleaning or transfer of the material cylinder, completely avoiding the problem of automation process interruption caused by traditional manual operation. At the same time, real-time feedback from sensors ensures accurate execution of each step, solving the problem of incomplete cleaning caused by the randomness of manual operation. This invention, through the design of the elastic sealing gasket between the material cylinder and the sealing cover, the negative pressure environment created by the vacuum generator, and the interception of dust-containing gas by the dust filter, forms a triple dustproof structure of "sealing-negative pressure-filtration". This not only eliminates the damage to the respiratory system of operators caused by dust dispersion during the cleaning process, but also avoids the safety hazards caused by flammable and explosive powders coming into contact with air. At the same time, it prevents dust from entering the precision parts of the equipment and causing wear, thus solving the defects of serious dust pollution and insufficient safety of traditional cleaning methods. This invention intercepts and recovers powder carried during the air extraction process using a dust filtration device. Combined with an optional powder recovery conveying pipe and electric butterfly valve, the filtered powder can be directly delivered to the powder supply chamber of the 3D printer, realizing the recycling and reuse of powder. This reduces material waste caused by powder residue and scattering in traditional cleaning methods. At the same time, by adapting to different components such as vacuum pumps or venturi tube vacuum generators, cylinders or electric push rods, it can be flexibly adjusted according to the space size of the 3D printer, the volume of the material cylinder, and other scenarios, solving the problems of poor adaptability and low material utilization rate of traditional cleaning solutions.

[0015] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the connection of the material cylinder of the present invention; Figure 2 This is a schematic diagram of the cylinder connection of the present invention; Figure 3 This is a connection diagram of the pressure sensor of the present invention; Figure 4 This is a connection diagram of the vacuum generating device of the present invention; Figure 5 This is a connection diagram of the pneumatic vacuum breaking device of the present invention; Figure 6 This is a connection diagram of the PLC controller of the present invention.

[0017] In the diagram: 1. Material cylinder; 2. Sealing cover; 3. Vacuum generator; 4. Dust filter; 5. Pneumatic vacuum breaking device; 6. PLC controller; 7. Pressure sensor; 8. Position sensor; 9. Cylinder; 10. Start button; 11. Stop button; 12. Emergency stop button; 13. Fault indicator light; 14. Running indicator light. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0020] Example 1 like Figure 1-6 As shown, this embodiment of the invention provides a PLC-controlled 3D printer powder cleaning system, including a material cylinder 1, a sealing cover 2, a vacuum generator 3, a dust filter 4, a pneumatic vacuum breaking device 5, a PLC controller 6, and a sensor group. The driving mechanism of the sealing cover 2 is a cylinder 9, the vacuum generating device 3 is a vacuum pump, the dust filtering device 4 is a high-efficiency air filter 13, the pneumatic vacuum breaking device 5 is a normally closed solenoid valve, and the sensor group includes a pressure sensor 7 and a position sensor 8. The input terminals of the PLC controller 6 are connected to the start button 16, stop button 17, emergency stop button 18, position sensor 8 and pressure sensor 7, and the output terminals are connected to the contactor coil of the vacuum pump, the normally closed solenoid valve, the control solenoid valve of the cylinder 9, the fault indicator light 19 and the running indicator light 20.

[0021] In this embodiment, after the 3D printing operation is completed, the operator presses the start button 16. The PLC controller 6 receives the start signal and first controls the solenoid valve of the cylinder 9 to actuate, driving the sealing cover 2 to close. After the position sensor 8 detects that the sealing cover 2 is closed, it sends a signal back to the PLC controller 6. The PLC controller 6 then starts the vacuum pump, drawing a vacuum into the material cylinder 1 through the first pipeline 9. The pressure sensor 7 monitors the vacuum level inside the material cylinder 1 in real time. When the vacuum level reaches -0.8 bar (a first preset threshold), it sends a signal back to the PLC controller 6. The controller 6 stops the vacuum pump and maintains a vacuum state for 5 minutes (preset time). After the maintenance time ends, the PLC controller 6 controls the normally closed solenoid valve to open, and clean gas from the gas source is injected into the material cylinder 1 through the second pipeline 10. When the pressure sensor 7 detects that the air pressure in the material cylinder 1 has returned to normal pressure (second preset threshold), the PLC controller 6 controls the normally closed solenoid valve to close and drives the cylinder 9 to open the sealing cover 2. At this time, the powder in the material cylinder 1 has been compacted, and the operator can safely remove the powder block. There is no dust dispersion throughout the process, and the operation is automated, improving cleaning efficiency.

[0022] Example 2 The difference between this embodiment and embodiment 1 is that: the vacuum generating device 3 uses a venturi tube vacuum generator instead of the vacuum pump in embodiment 1; Meanwhile, a temperature sensor (not shown) is added to the inner wall of the material cylinder 1. The temperature sensor is electrically connected to the PLC controller 6 and can monitor the temperature inside the material cylinder 1 in real time.

[0023] In this embodiment, the Venturi tube vacuum generator generates negative pressure by compressed air. Compared with a vacuum pump, it has a more compact structure, no moving mechanical parts, and lower maintenance costs, making it suitable for 3D printing equipment scenarios with limited space. The temperature sensor can monitor the powder temperature in the material cylinder 1. If the powder temperature is too high after printing (e.g., exceeding 60°C), the PLC controller 6 will delay starting the vacuum generator 3 and wait until the temperature drops below 40°C before performing the vacuuming operation. This avoids abnormal reactions of high-temperature powder under negative pressure (e.g., softening and sticking of polymer powder), further improving the system's safety and powder recovery quality. During the cleaning process, the dust filter 4 can still effectively filter the powder in the gas, ensuring that the Venturi tube vacuum generator is not contaminated by powder and maintains a stable working state.

[0024] Example 3 The difference between this embodiment and embodiment 2 is that the driving mechanism of the sealing cover 2 is an electric push rod (not shown), which replaces the cylinder 9 in embodiment 2; At the same time, a powder recovery conveying pipe (not shown) is added. One end of the powder recovery conveying pipe is connected to the powder discharge port of the dust filter device (4), and the other end is connected to the powder supply chamber (not shown) of the 3D printer. An electric butterfly valve (not shown) is installed on the conveying pipe and is electrically connected to the PLC controller 6.

[0025] In this embodiment, compared to cylinder 9, the electric push rod does not require a compressed air source, resulting in higher control precision. The closing pressure of the sealing cover 2 can be precisely adjusted by the PLC controller 6, further improving the sealing performance of the material cylinder 1 and preventing negative pressure leakage. When the powder collected in the dust filter 4 reaches a preset amount (which can be monitored by the material level sensor on the dust filter, which is electrically connected to the PLC controller), the PLC controller 6 controls the electric butterfly valve to open. The filtered powder is automatically transported to the powder supply chamber of the 3D printer through the recycling conveying pipe, realizing the recycling and reuse of powder and reducing material waste. The entire process does not require manual transfer of the filtered powder, further improving the automation level of the system and avoiding dust pollution that may be generated during manual powder transfer, which is in line with the concept of green production.

[0026] Working principle and usage process of this invention: Preparation stage: After the 3D printing job is completed, the equipment sends a "printing completed" signal to the PLC controller 6, the PLC controller 6 enters the cleanup state, and the operation indicator light 20 lights up; Sealing procedure: The operator presses the start button 16, and the PLC controller 6 drives the drive mechanism (cylinder or electric push rod) of the sealing cover 2 to close the sealing cover 2; the position sensor 8 detects whether the sealing cover 2 is closed in place. If it is not closed in place, the PLC controller 6 controls the drive mechanism to try to close it again. If it fails to close after multiple attempts, the fault indicator light 19 lights up and an alarm is triggered. Vacuuming steps: After confirming that the sealing cover 2 is closed in place, the PLC controller 6 starts the vacuum generator 3 and evacuates the material cylinder 1 through the first pipeline 9; when the gas flows through the dust filter 4, the powder it carries is filtered out, and the clean gas is discharged or enters the vacuum generator 3. Maintenance steps: Pressure sensor 7 provides real-time feedback on the vacuum level inside material cylinder 1. When the first preset threshold is reached, PLC controller 6 stops vacuum generator 3 and maintains negative pressure in material cylinder 1 for a preset time. Vacuum breaking step: After the maintenance time ends, the PLC controller 6 starts the pneumatic vacuum breaking device 5 to inject clean and dry gas into the material cylinder 1; the pressure sensor 7 monitors the air pressure, and when it returns to normal pressure (second preset threshold), the pneumatic vacuum breaking device 5 stops. Powder collection and opening procedure: PLC controller 6 drives the sealing cover 2 to open, and the operator or mechanical device takes out the compacted powder block; if it is necessary to recover the filtered powder, PLC controller 6 can control the relevant components to transport the powder in the dust filter device 4 to the powder supply bin. Troubleshooting: If the emergency stop button 18 is pressed during the process or the sensor detects an abnormality (such as abnormal vacuum or abnormal temperature), the PLC controller 6 will immediately stop all operations and the fault indicator light 19 will light up. After the fault is cleared, the cleaning process can be restarted.

[0027] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A PLC-controlled powder cleaning system for a 3D printer, comprising a material cylinder (1), a sealing cover (2), a vacuum generator (3), a dust filter (4), a pneumatic vacuum breaking device (5), a PLC controller (6), and a sensor group, characterized in that: The sealing cover (2) is movably disposed at the opening of the material cylinder (1), and its driving mechanism is a cylinder or an electric push rod; The vacuum generating device (3) is connected to the internal cavity of the material cylinder (1) through the first pipeline; The dust filter (4) is installed on the first pipeline and is located between the vacuum generator (3) and the material cylinder (1); The pneumatic vacuum breaking device (5) is a normally closed solenoid valve; The PLC controller (6) is electrically connected to the drive mechanism of the sealing cover (2), the vacuum generator (3), and the pneumatic vacuum breaking device (5), respectively. The sensor group is electrically connected to the PLC controller (6) and includes a pressure sensor (7) for detecting the vacuum level inside the material cylinder (1) and a position sensor (8) for detecting the status of the sealing cover (2).

2. The 3D printer powder cleaning system based on PLC control according to claim 1, characterized in that: The pressure sensor (7) is installed inside the material cylinder (1) or on the pipeline connected to the material cylinder (1), and can feed back the vacuum signal inside the material cylinder (1) to the PLC controller (6) in real time.

3. The 3D printer powder cleaning system based on PLC control according to claim 1, characterized in that: The position sensor (8) is a normally open PNP sensor that can detect the open or closed state of the sealing cover (2) and transmit the status signal to the PLC controller (6).

4. The 3D printer powder cleaning system based on PLC control according to claim 1, characterized in that: The PLC controller (6) can receive the sealing cover closing signal from the position sensor (8) and then start the vacuum generator (3); when the pressure sensor (7) detects that the vacuum level reaches the first preset threshold, the PLC controller (6) controls the vacuum generator (3) to stop working.

5. The 3D printer powder cleaning system based on PLC control according to claim 1, characterized in that: After the vacuum generator (3) stops working, the PLC controller (6) can maintain the vacuum state of the material cylinder (1) for a preset time, or when it receives the powder collection completion instruction, it can control the pneumatic vacuum breaking device (5) to inject gas into the material cylinder (1).

6. The PLC-controlled 3D printer powder cleaning system according to claim 1, characterized in that: When the pressure sensor (7) detects that the air pressure in the material cylinder (1) has returned to the second preset threshold (normal pressure), the PLC controller (6) controls the pneumatic vacuum breaking device (5) to stop working and drives the drive mechanism of the sealing cover (2) to open the sealing cover (2).

7. The 3D printer powder cleaning system based on PLC control according to claim 1, characterized in that: The PLC controller (6) drives the drive mechanism of the sealing cover (2) to open and close by controlling the solenoid valve or relay.

8. The PLC-controlled 3D printer powder cleaning system according to claim 1, characterized in that: When the vacuum generator (3) is working, the gas drawn from the material cylinder (1) flows through the dust filter (4), and the powder particles carried in the gas are filtered out. The clean gas can be discharged or enter the vacuum generator (3).

9. The PLC-controlled 3D printer powder cleaning system according to claim 1, characterized in that: The input terminal of the PLC controller (6) is connected to the start button (10), the stop button (11), and the emergency stop button (12). The output terminal of the PLC controller (6) is connected to the contactor coil of the vacuum pump, the normally closed solenoid valve, the control solenoid valve of the cylinder (9), the fault indicator (13), and the running indicator (14).

Images