Additive manufacturing powder supplementing device

Abstract

The invention discloses a powder supplementing device for additive manufacturing, and aims to solve the problems that feeding interruption is easily caused and self-healing dredging cannot be realized when powder bridging or a discharging space of existing equipment is limited. The device comprises a controller and a feeding module, and the feeding module is provided with a discharging guide cylinder, a discharging assembly movably arranged in the discharging guide cylinder in a penetrating mode, a flow adjusting assembly, a distance sensor and a lifting driving mechanism, the controller obtains the actual powder falling distance in real time through the sensor, calculates the powder accumulation rate during normal powder falling and controls the lifting driving mechanism to conduct closed-loop follow-up lifting. And when the stacking rate is abnormally low, intelligent fault diagnosis is carried out according to a comparison result of an actual distance and a second preset distance, and the self-healing intervention logic of controlling the adjusting assembly to carry out opening degree reciprocating change so as to break an internal bridge or preferentially lifting the discharging assembly so as to release an external discharging space is executed. According to the invention, full-automatic closed-loop powder supplement is realized, and the processing continuity is obviously guaranteed.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing equipment technology, and more specifically, to a powder replenishment device for multi-material powder bed additive manufacturing. Background Technology

[0002] In powder bed additive manufacturing, a continuous and stable supply of powder to the powder storage tank is fundamental to ensuring the quality of the final printed parts. Most existing powder replenishment devices employ simple gravity-feeding or mechanical feeding structures, relying on a fixed speed or stroke for feeding. However, powder materials such as metal micropowders are highly susceptible to mutual compression during flow due to interparticle friction, static electricity, or slight moisture absorption. This forms stable arched structures within the feeding channel, interrupting powder feeding and severely impacting the processing.

[0003] Meanwhile, existing powder replenishment equipment generally lacks real-time powder discharge status monitoring and closed-loop feedback mechanisms. In actual powder replenishment, a blind pushing method is often used, which cannot detect whether bridging blockage has occurred inside the device, nor can it detect whether the discharge space at the bottom of the device is already filled with accumulated powder. This one-way control logic easily leads to insufficient powder replenishment or large amounts of powder accumulation and overflow. When abnormalities occur, manual shutdown and physical unblocking are the only options, which is difficult to meet the stringent requirements of high-precision additive manufacturing for automated equipment operation and feeding stability. Summary of the Invention

[0004] To address the aforementioned shortcomings in the existing technology, this invention provides an additive manufacturing powder replenishment device, which aims to solve the technical problems of existing powder replenishment equipment being unable to accurately monitor the powder falling status, and being prone to feeding interruption and inability to recover autonomously when powder bridging occurs internally or external discharge space is limited.

[0005] The additive manufacturing powder replenishing device provided by the present invention is used to replenish powder to a powder storage tank, including a controller and a feeding module; The feeding module includes: The hopper stores powder and has a discharge guide at the bottom. The feeding assembly is movably installed inside the feeding guide cylinder for discharging the powder; A flow rate regulating component, located at the bottom of the feeding component, is used to regulate the flow rate of the discharged powder by changing its own opening. The lifting drive mechanism is connected to the unloading component and is used to drive the unloading component to move up and down along the unloading guide cylinder; A distance sensor is located at the bottom of the feeding assembly to obtain the actual distance between the bottom and the powder surface in the powder storage tank in real time and send it to the controller. The controller is configured as follows: The lifting drive mechanism is controlled to drive the unloading component to descend to the actual distance of the first preset distance; The flow regulation component is controlled to start the powder feeding process. The accumulation rate of powder in the powder storage tank is calculated based on the continuously acquired actual distance. The lifting drive mechanism is controlled to drive the feeding component to lift so that the actual distance is dynamically maintained at the first preset distance. During the powder dropping process, when the accumulation rate is lower than the preset target rate, the controller interrupts the lifting drive mechanism to drive the unloading component to lift and triggers abnormal intervention, comparing the current actual distance with a second preset distance that is less than the first preset distance; If the actual distance is greater than the second preset distance, it is determined that powder bridging has occurred inside the feeding component. The flow regulating component is controlled to reciprocate to break the powder bridging. Then the flow regulating component is controlled to stop reciprocating and restore its opening to the state before the reciprocating was triggered. Then the opening of the flow regulating component is increased. If the actual distance is not greater than the second preset distance, it is determined that the discharge space at the bottom of the feeding component is limited. The lifting drive mechanism is first controlled to raise the feeding component to release the discharge space, and then the opening of the flow regulating component is increased.

[0006] Preferably, the feeding assembly is a hollow tube with openings at both ends, with the top opening forming a powder inlet located inside the feeding guide tube.

[0007] Preferably, the flow regulating component is an electrically controlled regulating valve, which is fixedly installed at the bottom opening of the feeding component; The electrically controlled regulating valve is signal-connected to the controller and configured to receive electrical signals from the controller and drive its internal actuators to operate.

[0008] Preferably, the electrically controlled regulating valve is an electric aperture valve.

[0009] Preferably, the side wall of the feeding guide cylinder is provided with an axially extending elongated guide hole; The lifting drive mechanism includes: Drive motor; A linear transmission assembly is fixedly arranged on the outer side wall of the hopper and is connected to the output shaft of the drive motor. The transmission bracket has one end connected to the moving part of the linear transmission assembly, and the other end passes through the elongated guide hole and extends into the feeding guide cylinder, and is fixedly connected to the feeding assembly.

[0010] Preferably, the outer wall of the feeding assembly is in close sliding contact with the inner wall of the feeding guide cylinder, and the gap between the two is smaller than the particle size of the powder. Throughout the entire stroke range of the unloading assembly driven to rise and fall by the lifting drive mechanism, the sidewalls of the unloading assembly completely cover the elongated guide hole.

[0011] Preferably, the step of the controller calculating the stacking rate based on the continuously acquired actual distance includes: Extract multiple historical actual distances within a preset sliding time window; The actual distances in the multiple historical data are smoothed and filtered to remove abrupt noise, and the rate of change of the filtered data over time is calculated. The absolute value of the rate of change is determined as the accumulation rate.

[0012] Preferably, the specific process by which the flow control adjustment component reciprocates to break the powder bridging is as follows: The electronically controlled regulating valve is controlled to switch between its maximum pulse frequency and minimum pulse frequency, or to switch back and forth between its maximum physical opening and minimum physical opening.

[0013] Preferably, the specific process of prioritizing the lifting drive mechanism to raise the unloading assembly to release the discharge space is as follows: The lifting drive mechanism is controlled to drive the unloading assembly to retract upward by a preset step length; If the actual distance obtained after rollback is still not greater than the second preset distance, the rollback action is repeated until the actual distance is greater than the second preset distance before the opening of the flow regulation component is increased.

[0014] One or more technical solutions provided in this invention have at least the following technical effects or advantages: This invention utilizes a distance sensor at the bottom of the feeding assembly to obtain the actual distance between the powder drop point and the powder surface in the powder storage tank in real time. Combined with a controller, this allows for the calculation of the powder accumulation rate, thus constructing a highly agile closed-loop following system. This system enables the feeding assembly to automatically follow and rise with the powder surface during normal powder feeding, maintaining a dynamic, preset distance from the powder surface at all times. This not only avoids interference between the bottom of the feeding assembly and the powder but also ensures free-fall feeding from a constant height, greatly improving the uniformity and stability of powder replenishment.

[0015] Furthermore, this invention possesses extremely high intelligent fault diagnosis and self-healing capabilities. When the system detects an abnormally low powder accumulation rate, it can accurately identify the true physical cause of the powder replenishment obstruction by comparing the current actual distance with a set second preset distance. If the actual distance is still greater than the second preset distance, the system can accurately determine that powder bridging has occurred inside the feeding assembly, and control the flow regulating component at the bottom of the feeding assembly to repeatedly change its opening. The physical disturbance generated by the dynamic opening and closing directly disrupts the force balance of the powder inside the feeding assembly to break the powder bridging, and then automatically restores and increases the powder flow rate.

[0016] If the actual distance is not greater than the second preset distance, the system determines that the external material discharge space is already confined and full. At this time, the controller prioritizes instructing the lifting drive mechanism to actively raise the material feeding component to release the bottom discharge space, and then increases the opening of the flow regulation component to continue replenishing powder. This dual anomaly diagnosis and graded intervention mechanism based on spatial distance logic breaks through the limitations of blind material feeding in traditional powder replenishment devices, and realizes a fully automatic closed loop from status monitoring, cause diagnosis to fault clearing, significantly reducing the frequency of manual intervention in the equipment and fully ensuring the continuity of the additive manufacturing process. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the overall structure of the additive manufacturing powder replenishment device provided in an embodiment of the present invention; Figure 2 This is a block diagram illustrating the control principle of the additive manufacturing powder replenishment device provided in an embodiment of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 10, feeding module; 11, hopper; 111, discharge guide cylinder; 1111, elongated guide hole; 12, discharge assembly; 121, powder inlet; 13, flow regulation assembly; 14, lifting drive mechanism; 141, drive motor; 142, linear transmission assembly; 143, transmission bracket; 15, distance sensor; 20, controller; 30, powder storage tank. Detailed Implementation

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1 and Figure 2 As shown, this invention provides an additive manufacturing powder replenishment device, mainly used for high-precision, anti-clogging automated powder replenishment into the powder storage tank 30 of a 3D printing equipment. Structurally, the device mainly includes a controller 20 responsible for overall control and algorithm calculation, and a feeding module 10 responsible for physically executing the material feeding action.

[0022] Specifically, the top of the feeding module 10 is provided with a hopper 11 for storing printing raw materials such as metal micro powder. To guide the powder to fall in a directional manner, the bottom end of the hopper 11 is integrally formed or fixedly connected to a downwardly extending vertical feed guide cylinder 111. A core feed assembly 12 is movably inserted into the internal cavity of the feed guide cylinder 111. The feed assembly 12 is preferably a rigid hollow tube with openings at both ends. To ensure smooth powder entry, the top opening of the hollow tube directly forms a powder inlet 121, and the powder inlet 121 is always located inside the feed guide cylinder 111 throughout the entire working cycle, so that the powder in the hopper 11 can naturally gather by gravity and enter the powder flow channel inside the hollow tube through the powder inlet 121.

[0023] To achieve precise flow control, a flow regulating component 13 is integrated into the bottom opening of the feeding assembly 12. In practical engineering applications, to avoid the traditional rigid shut-off valve from crushing expensive spherical metal powder, the flow regulating component 13 is preferably an electrically controlled regulating valve, especially an electric iris valve, i.e., a diaphragm valve. The electric iris valve changes the opening of the central through-hole by the centripetal contraction of multiple flexible overlapping blades inside, forming a flexible wrapping of the powder, thereby ensuring the integrity of the powder's physical morphology while forming a vertical and uniform powder flow. Of course, as an alternative equivalent implementation, in micro-additive manufacturing scenarios where the single powder replenishment accuracy requirement is extremely high or where extremely high frequency arch breaking is required, the electrically controlled regulating valve can also be a piezoelectric micro-powder dispensing valve; while in scenarios where the powder integrity requirement is relatively broad, an electric micro-rotary disc valve can also be used. All of the above-mentioned electrically controlled regulating valves are connected to the controller 20, and can directly receive electrical signals and quickly drive the internal actuators, greatly simplifying the complex mechanical transmission structure in traditional powder replenishment devices and improving the system's integration and response speed.

[0024] In terms of the drive structure, the feeding module 10 is equipped with a lifting drive mechanism 14 to control the height of the unloading assembly 12 in the Z-axis direction. Specifically, an elongated guide hole 1111 extending axially is provided on the side wall of the unloading guide cylinder 111. The lifting drive mechanism 14 includes a linear transmission assembly 142 fixedly arranged on the outer wall of the hopper 11, and a drive motor 141 that provides power to it. The linear transmission assembly 142 here can adopt a ball screw slide module, a synchronous belt linear module, or a gear and rack transmission mechanism, etc., or an equivalent structure. One end of the transmission bracket 143 is connected to the moving part of the linear transmission assembly 142, and the other end passes laterally through the elongated guide hole 1111 and extends into the unloading guide cylinder 111, and is finally firmly fixed to the outer wall of the unloading assembly 12.

[0025] To address the potential powder leakage issue caused by the elongated guide hole 1111, this invention proposes a self-sealing slide valve structure. The outer cylindrical surface of the feeding assembly 12 and the inner cylindrical surface of the feeding guide cylinder 111 are tightly fitted together, with the clearance between them precisely machined to be smaller than the minimum particle size of the loaded powder. For example, when replenishing powder for 3D printing titanium or aluminum alloy micropowders with a typical particle size distribution of 15 to 53 micrometers, the clearance is precisely controlled between 5 and 10 micrometers. Furthermore, the axial length of the elongated guide hole 1111 is rationally configured to accommodate a preset lifting stroke, ensuring that the solid, non-porous sidewalls of the feeding assembly 12 completely cover the elongated guide hole 1111 throughout the entire stroke range of the feeding assembly 12's up-and-down movement driven by the lifting drive mechanism 14. This design utilizes the geometry of the moving parts to construct a physical barrier, effectively blocking the powder leakage path. This zero-consumables, no-additional-seals design not only eliminates the risk of aging and damage to traditional rubber seals, but also improves the mechanical reliability and maintenance-free cycle of the device.

[0026] To achieve intelligent closed-loop powder replenishment, the present invention also mounts a distance sensor 15 at the bottom of the feeding assembly 12. This distance sensor 15 can be a high-precision laser rangefinder, ultrasonic sensor, or infrared rangefinder module, etc., to obtain the actual physical distance between its detection end face and the highest powder accumulation surface in the powder storage tank 30 below in real time and continuously, and transmit this distance data back to the controller 20 at high frequency.

[0027] Based on the aforementioned hardware, the controller 20 incorporates a highly agile closed-loop tracking and anomaly diagnosis algorithm. At the initial stage of powder replenishment, the controller 20 first instructs the lifting drive mechanism 14 to lower the feeding component 12 until the actual distance fed back by the distance sensor 15 reaches the set first preset distance. In actual processing, this first preset distance is the optimal free-falling powder height, typically set within the range of 10 mm to 20 mm, preferably 15 mm. Subsequently, the controller 20 instructs the flow regulation component 13 to start powder falling. During the powder falling process, the controller 20 does not blindly wait but instead extracts multiple historical actual distance data points within a preset sliding time window in real time. Preferably, this sliding time window can be set to 0.5 seconds to 2.0 seconds, for example, a window period of the past 1.0 second, supplemented by a data sampling frequency of 100 Hz. The controller 20 uses a smoothing filter to remove abrupt noise from the data within the window, and then calculates the rate of change of the filtered distance data over time. The absolute value of this rate of change accurately represents the actual powder accumulation rate in the current powder storage tank 30. As the powder plane continues to rise, the controller 20 controls the lifting drive mechanism 14 to perform a closed-loop upward following motion in real time, ensuring that the discharge port is always dynamically suspended at the first preset distance above the powder surface in the powder storage tank 30, thereby avoiding large-scale dust flying and ensuring the uniformity of powder density.

[0028] When the system detects that the calculated powder accumulation rate is lower than the preset target rate, it means that powder replenishment is hindered. The controller 20 will immediately and actively interrupt the current closed-loop following lifting action and trigger an abnormal intervention procedure, logically comparing the current actual distance with a second preset distance that is less than the first preset distance. This second preset distance serves as a safety red line distance for collision avoidance and is typically set between 2 mm and 5 mm, preferably 3 mm.

[0029] If the comparison result shows that the actual distance is greater than the second preset distance, it indicates that the discharge space below is still sufficient, but the powder has failed to fall as expected. Based on this, the controller 20 determines that static bridging of powder has occurred inside the feeding assembly 12. At this time, the controller 20 immediately instructs the electronically controlled regulating valve to perform high-frequency reciprocating changes in opening. For example, when using a piezoelectric micro-powder dispensing valve, it can be controlled to generate micro-amplitude mechanical oscillations at a high frequency of 50 Hz to 500 Hz, preferably 100 Hz; when using an electric aperture valve, it can be controlled to rapidly rub between large and small physical openings. This physical disturbance can quickly disrupt the mechanical balance of the powder arch bridge to achieve self-healing and arch breaking, and then the system smoothly increases the opening to continue replenishing powder.

[0030] Conversely, if the comparison results show that the actual distance is no greater than the second preset distance, it indicates that the blockage is not internal, but rather that the discharge space at the bottom of the feeding component 12 has been substantially filled and restricted. In this situation, the controller 20 prioritizes the obstacle avoidance logic, instructing the lifting drive mechanism 14 to retract one preset step. If the actual distance after retraction still does not meet the safety requirements, the retraction step action is repeated until the actual distance is again greater than the second preset distance, establishing sufficient powder discharge space. To quickly compensate for the powder loss during the restricted period, the valve opening is increased to restore a large flow of powder. This dual-logic diagnostic mechanism based on spatial distance and time window gives the powder replenishment device extremely high fault tolerance and fully automatic unblocking capability in unattended environments.

Claims

1. An additive manufacturing powder replenishing device for replenishing powder to a powder storage tank (30), characterized in that, Includes a controller (20) and a feeding module (10); The feeding module (10) includes: The hopper (11) stores powder and has a discharge guide cylinder (111) at the bottom. The feeding assembly (12) is movably inserted into the feeding guide cylinder (111) for discharging the powder; A flow rate regulating component (13) is located at the bottom of the feeding component (12) and is used to regulate the flow rate of the powder discharged by changing its own opening. The lifting drive mechanism (14) is connected to the unloading assembly (12) and is used to drive the unloading assembly (12) to rise and fall along the unloading guide cylinder (111); A distance sensor (15) is located at the bottom of the feeding assembly (12) to obtain the actual distance between the bottom and the powder surface in the powder storage tank (30) in real time and send it to the controller (20). The controller (20) is configured as follows: The control lifting drive mechanism (14) drives the unloading assembly (12) to descend to the actual distance of the first preset distance; The flow control component (13) is activated to discharge powder. The accumulation rate of powder in the powder storage tank (30) is calculated based on the continuously acquired actual distance. The lifting drive mechanism (14) is controlled to drive the feeding component (12) to lift, so that the actual distance is dynamically maintained at the first preset distance. During the powder dropping process, when the accumulation rate is lower than the preset target rate, the controller (20) interrupts the lifting drive mechanism (14) to drive the feeding component (12) to lift and triggers abnormal intervention, and compares the current actual distance with a second preset distance that is less than the first preset distance; If the actual distance is greater than the second preset distance, it is determined that powder bridging has occurred inside the feeding component (12). The flow regulating component (13) is controlled to perform reciprocating opening changes to break the powder bridging. Then, the flow regulating component (13) is controlled to stop performing the reciprocating opening changes and its opening is restored to the state before the reciprocating opening changes are triggered. Then, the opening of the flow regulating component (13) is increased. If the actual distance is not greater than the second preset distance, it is determined that the discharge space at the bottom of the feeding component (12) is limited. The lifting drive mechanism (14) is controlled first to lift the feeding component (12) to release the discharge space, and then the opening of the flow regulating component (13) is increased.

2. The additive manufacturing powder replenishment device according to claim 1, characterized in that, The feeding assembly (12) is a hollow tube with openings at both ends. Its top opening forms a powder inlet (121) and is located inside the feeding guide tube (111).

3. The additive manufacturing powder replenishment device according to claim 2, characterized in that, The flow regulating component (13) is an electrically controlled regulating valve, which is fixedly installed at the bottom opening of the feeding component (12); The electrically controlled regulating valve is signal-connected to the controller (20) and configured to receive electrical signals from the controller (20) and drive its internal actuators to operate.

4. The additive manufacturing powder replenishment device according to claim 3, characterized in that, The electrically controlled regulating valve is an electric aperture valve.

5. The additive manufacturing powder replenishment device according to claim 2, characterized in that, The side wall of the feeding guide cylinder (111) is provided with an axially extending elongated guide hole (1111). The lifting drive mechanism (14) includes: Drive motor (141); A linear transmission assembly (142) is fixedly arranged on the outer side wall of the hopper (11) and is connected to the output shaft of the drive motor (141) for transmission. The transmission bracket (143) is connected at one end to the moving part of the linear transmission assembly (142), and at the other end passes through the elongated guide hole (1111) and extends into the unloading guide cylinder (111), and is fixedly connected to the unloading assembly (12).

6. The additive manufacturing powder replenishment device according to claim 5, characterized in that, The outer wall of the feeding assembly (12) is in close sliding contact with the inner wall of the feeding guide cylinder (111), and the gap between the two is smaller than the particle size of the powder. Throughout the entire stroke range of the material feeding assembly (12) being driven to rise and fall by the lifting drive mechanism (14), the sidewalls of the material feeding assembly (12) completely cover the elongated guide hole (1111).

7. The additive manufacturing powder replenishment device according to claim 1, characterized in that, The step of the controller (20) calculating the stacking rate based on the continuously acquired actual distance includes: Extract multiple historical actual distances within a preset sliding time window; The actual distances in the multiple historical data are smoothed and filtered to remove abrupt noise, and the rate of change of the filtered data over time is calculated. The absolute value of the rate of change is determined as the accumulation rate.

8. The additive manufacturing powder replenishment device according to claim 3, characterized in that, The specific process by which the flow control component (13) reciprocates in opening to break the powder bridging is as follows: The electronically controlled regulating valve is controlled to switch between its maximum pulse frequency and minimum pulse frequency, or to switch back and forth between its maximum physical opening and minimum physical opening.

9. The additive manufacturing powder replenishment device according to claim 1, characterized in that, The specific process by which the priority control lifting drive mechanism (14) raises the unloading assembly (12) to release the discharge space is as follows: The lifting drive mechanism (14) is controlled to drive the unloading assembly (12) to retract upward by a preset step length; If the actual distance obtained after the rollback is still not greater than the second preset distance, the rollback action is repeated until the actual distance is greater than the second preset distance before the opening of the flow regulation component (13) is increased.

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