3D printing powder feeding device based on non-uniform-speed inner geneva wheel powder distribution

Abstract

The invention provides a 3D printing powder feeding device based on non-uniform-speed inner grooved wheel powder distribution, and belongs to the technical field of 3D printing. The feeding device comprises a shell, a powder distributing assembly and a melt-blowing assembly. The shell is provided with a feeding cavity and a powder distributing cavity. The powder distribution assembly comprises inner grooved wheels and a regulation and control rod, the inner grooved wheels are rotationally connected with the shell, a powder distribution gap is formed between the two inner grooved wheels, the rotating directions of the two inner grooved wheels are opposite, the inner grooved wheels are provided with regulation and control grooves and regulation and control openings, the regulation and control rod rotates with the axis parallel to the rotating shaft of the inner grooved wheels as the rotating shaft, and the regulation and control rod is provided with regulation and control protrusions; and the regulation and control bulge can move into the regulation and control groove from the regulation and control opening, the regulation and control bulge abuts against the groove wall of the regulation and control groove so that the inner grooved wheel can have a first rotating speed, or the regulation and control bulge moves into the regulation and control opening from the regulation and control groove, and the regulation and control bulge is separated from the inner grooved wheel so that the speed of the powder passing through the powder distribution gap can be regulated and controlled. The melt-blowing assembly is provided with a melting cavity and a discharging opening. According to the invention, the matching degree of powder feeding and powder melting rate can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation. Background Art

[0002] Related FDM (Fused Deposition Modeling) 3D printing technologies rely on filamentary materials, which poses challenges such as high material preparation costs and limited material options. Powder direct melting FDM technology overcomes the limitations of filament preparation by directly heating and melting powder materials before extruding them into shape. It is compatible with a variety of powder materials, including metals, ceramics, and polymers, significantly reducing material costs.

[0003] In the related technology, the powder direct melting device has the problem of mismatch between powder feed and melting rate: when the powder is distributed at a uniform speed, the powder is easily accumulated in the melting chamber, resulting in local overheating and coking, or extrusion interruption due to insufficient supply; at the same time, the melting temperature and fluidity of different powder materials (such as PA6 powder and stainless steel powder) vary greatly, and traditional open-loop control is difficult to achieve precise temperature-feed coordinated adjustment, resulting in defects such as bubbles and stratification in the printed parts. Summary of the Invention

[0004] The present invention provides a 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation, the purpose of which is to improve the matching degree between powder feeding and powder melting rate.

[0005] In order to achieve the above-mentioned object, the present invention provides a 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation, comprising:

[0006] a housing having a feed chamber and a powder distribution chamber that are interconnected, wherein the feed chamber is configured to store or feed powder for 3D printing;

[0007] The powder distributing assembly of claim 1, wherein the inner groove wheel is rotatably connected to the outer shell, and at least a portion of the structure of the inner groove wheel is located in the powder distributing chamber. The number of the inner groove wheels is two, and a powder distributing gap is formed between the two inner groove wheels, and the powder distributing gap is communicated with the powder distributing chamber. The two inner groove wheels rotate in opposite directions, and the inner groove wheels have mutually communicated regulating grooves and regulating ports, and the regulating rod can rotate with an axis parallel to the rotation axis of the inner groove wheel as the rotation axis, and the regulating rod has a regulating protrusion, and when the regulating rod rotates, the regulating protrusion can move from the regulating port into the regulating groove, and the regulating protrusion abuts against the groove wall of the regulating groove, so that the inner groove wheel has a first speed, or the regulating protrusion can move from the regulating groove into the regulating port to disengage the regulating protrusion from the inner groove wheel, so that the inner groove wheel slows down, so as to regulate the speed of the powder passing through the powder distributing gap;

[0008] The meltblown component has a melting chamber and a discharge port that are interconnected. The melting chamber is connected to the powder separation gap. The melting chamber is configured to melt the powder fed through the powder separation gap so that the powder is in a molten state. The discharge port is configured to spray out the powder in a molten state.

[0009] In one embodiment, the regulating rod further has a friction protrusion, and the friction protrusion and the regulating protrusion are arranged relative to each other along the axial direction of the regulating rod. The inner groove wheel includes a wheel body and a plurality of friction protrusions, and the plurality of friction protrusions are arranged at intervals on the first circumference of the wheel body. The regulating groove and the regulating port are formed in the wheel body. When the regulating protrusion moves from the regulating groove to the regulating port, the friction protrusion can frictionally contact the friction protrusion so that the inner groove wheel has a second rotational speed, and the second rotational speed is less than the first rotational speed.

[0010] In one embodiment, the wheel body includes an outer ring and an inner disc, the inner wall of the outer ring is connected to the outer wall of the inner disc, the control groove and the control port are formed on the inner disc, the first circumference is located on the inner disc, the rotation center of the control rod is located on the outside of the powder dividing chamber, and the outer ring is rotatably sealed with the outer shell on both opposite sides along its own axis.

[0011] In one embodiment, the air pressure in the powder separation chamber is greater than atmospheric pressure.

[0012] In one embodiment, the feeding device includes a stirring member, which is arranged in the feed chamber. The stirring member includes a rotating rod and a spiral blade. The rotating rod is rotatably connected to the wall of the feed chamber, and the spiral blade is arranged in a spiral shape and extends along the axial direction of the rotating rod. The radial size of the spiral blade in the rotating rod gradually changes along the axial direction of the rotating rod.

[0013] In one embodiment, there are multiple stirring members, the multiple stirring members are arranged at intervals, two adjacent stirring members are configured to be centrally symmetrical, and the rotation directions of the two adjacent stirring members are opposite.

[0014] In one embodiment, the feeding device includes a first cleaning member, which includes a fixed scraper and an elastic scraper. The fixed scraper and the elastic scraper are both arranged in the outer shell. Along the rotation direction of the inner groove wheel, the fixed scraper is arranged behind the elastic scraper. A first cleaning gap is formed between the fixed scraper and the inner groove wheel, and a second cleaning gap is formed between the elastic scraper and the inner groove wheel. The size of the first cleaning gap is larger than the size of the second cleaning gap.

[0015] In one embodiment, the feeding device includes a second cleaning member, which is configured as a piezoelectric ceramic piece. The piezoelectric ceramic piece is disposed on the rotating shaft of the inner groove wheel to make the inner groove wheel vibrate at a preset frequency.

[0016] In one embodiment, the meltblown assembly includes a melting part and a nozzle, the melting part includes an electromagnetic induction coil and a melting shell, the melting shell has the melting cavity, the electromagnetic induction coil surrounds the outer periphery of the melting shell so that the powder located in the melting cavity is in a molten state, and the nozzle has the discharge port.

[0017] In one embodiment, the feeding device includes an electrically connected monitoring component and a controller, and the controller is configured to receive a monitoring signal from the monitoring component to adjust the powder separation component and the meltblowing component. The monitoring component includes a powder flow sensor, a melting temperature sensor, a melt viscosity sensor and a nozzle pressure sensor. The powder flow sensor is arranged downstream of the powder separation gap to monitor the flow rate of the powder, the melt temperature sensor is arranged in the melting chamber to monitor the temperature in the melting chamber, the melt viscosity sensor is arranged between the melting chamber and the discharge port to monitor the viscosity of the powder in a molten state, and the nozzle pressure sensor is arranged at the discharge port to monitor the pressure of the powder at the discharge port.

[0018] The above solution of the present invention has the following beneficial effects:

[0019] In the embodiment of the present application, when the regulating rod rotates, the regulating protrusion can switch between the regulating groove and the regulating port. When the regulating protrusion enters the regulating groove from the regulating port, the regulating protrusion can abut against the inner wall of the regulating groove to drive the inner groove wheel to rotate. The rotation speed of the inner groove wheel is relatively fast, so that the flow rate of the powder entering the melting chamber through the powder separation gap is relatively large, so as to reduce the possibility of interruption of the powder in the molten state outputted by the discharge port. When the regulating protrusion moves from the regulating groove to the regulating port, the regulating protrusion is disengaged from the inner groove wheel, and the rotation speed of the inner groove wheel is relatively slow, so that the flow rate of the powder entering the melting chamber through the powder separation gap is relatively small, so as to reduce the possibility of powder accumulation in the melting chamber. When the regulating rod rotates at a uniform speed, the rotation speed of the inner groove wheel can be changed periodically, so that the powder in the powder separation chamber can pass through the powder separation gap by relying on its own gravity and driven by the inner groove wheel with a periodically changing flow rate. Properly controlling this cycle can improve the matching between the powder feed rate and the powder melting rate, thereby preventing powder from accumulating in the melting chamber and allowing molten powder to be continuously ejected from the discharge port, which helps improve the quality of 3D printing. Furthermore, the size of the powder separation gap can be adjusted to accommodate a variety of powder sizes without having to replace the entire feed mechanism.

[0020] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of a 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation in one embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the assembly of a powder separation component in one embodiment of the present invention;

[0023] Figure 3 Schematic diagram of a top view of a 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation in one embodiment of the present invention;

[0024] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at AA in the middle;

[0025] Figure 5 for Figure 4 A magnified schematic diagram of the structure at B in the middle;

[0026] Figure 6 Schematic diagram of the assembly of two adjacent stirring members in one embodiment of the present invention.

[0027] [Description of Reference Numerals]

[0028] 1. Outer shell; 1a. Feed chamber; 1b. Powder separation chamber; 2. Powder separation assembly; 21. Inner groove wheel; 21a. Powder separation gap; 21b. Control groove; 21ba. First groove; 21bb. Second groove; 21c. Control port; 211. Wheel body; 2111. Outer ring; 2112. Inner disc; 212. Friction bulge; 22. Control rod; 221. Control protrusion; 222. Friction protrusion; 3. Meltblown assembly; 3a. Melting chamber; 3b. Discharge port; 31. Melting part; 311. Electromagnetic induction coil; 312. Melting shell; 32. Nozzle; 4. Stirring part; 41. Rotating rod; 42. Spiral blade; 51. Powder flow sensor; 52. Melting temperature sensor; 53. Melting viscosity sensor; 54. Nozzle pressure sensor. DETAILED DESCRIPTION

[0029] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood in a broad sense, for example, it can be a locking connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] In the related art, since the matching degree of the powder feeding rate of the powder direct melting device and the melting rate of the powder is not high, when the feeding rate of the powder is large, the powder is easy to accumulate in the melting cavity, causing local overheating and coking of the powder accumulation body, and when the feeding rate of the powder is low, the powder in a molten state is easy to output discontinuously at the discharge port, resulting in poor forming quality of 3D printing.

[0033] Therefore, the present application provides a 3D printing powder feeding device based on non-uniform speed inner groove wheel powder distribution, which optimizes the structure of the powder distribution assembly to make the speed of the inner groove wheel change periodically, so that the flow of the powder transported into the melting cavity through the powder distribution gap changes periodically. By reasonably controlling this period, the matching degree of the powder feeding rate and the melting rate of the powder can be improved, which is beneficial to improving the forming quality of 3D printing.

[0034] Specifically, please refer to Figure 1 The feeding device of the present application comprises a shell 1, a powder distribution assembly 2 and a melt blowing assembly 3.

[0035] Please refer to Figure 1 、 Figure 3 and Figure 4The material of the outer shell 1 can be a material with certain strength and hardness, such as metal. The outer shell 1 can be fixed to the frame of the 3D printer, so that the outer shell 1 can move in the three-dimensional space under the drive of the frame. The outer shell 1 has a feeding cavity 1a and a powder distribution cavity 1b which are in communication with each other. The feeding cavity 1a is configured to store or feed the powder used for 3D printing. For example, the powder can enter the outer shell 1 from the feeding cavity 1a in an open state, and then enter the powder distribution cavity 1b. For example, the material of the powder can be configured as a polymer powder.

[0036] Please refer to Figure 1 、 Figure 2 and Figure 4 , the powder distribution assembly 2 includes an inner groove wheel 21 and a control rod 22. The inner groove wheel 21 is rotationally connected with the outer shell 1. At least part of the structure of the inner groove wheel 21 is located in the powder distribution cavity 1b. The number of the inner groove wheel 21 is two, and the two inner groove wheels 21 form a powder distribution gap 21a therebetween, which is in communication with the powder distribution cavity 1b, so that when the powder enters the powder distribution cavity 1b from the feeding cavity 1a, it can enter the powder distribution gap 21a. It should be noted that the size of the powder distribution gap 21a is small, and when the two inner groove wheels 21 are not rotating, few powders can pass through the powder distribution gap 21a. The rotation directions of the two inner groove wheels 21 are opposite. For example, Figure 4 , the inner groove wheel 21 located on the left side can rotate clockwise, and the inner groove wheel 21 located on the right side can rotate counterclockwise, so that the powder can pass through the powder distribution gap 21a under the action of its own gravity and the inner groove wheel 21. Please refer to Figure 2The inner-groove wheel 21 has a control groove 21b and a control port 21c which are in communication with each other. For example, the control groove 21b and the control port 21c both extend through the inner-groove wheel 21 along the axial direction of the inner-groove wheel 21. The control rod 22 is rotatable about an axis which is parallel to the rotation axis of the inner-groove wheel 21. For example, the outer circumferential side of the control rod 22 is connected to a servo motor (not shown in the figure), and the servo motor is connected to the frame of the 3D printer, so that the control rod 22 can move in unison with the inner-groove wheel 21 during 3D printing (the shell 1 moves in the three-dimensional space under the drive of the frame). The control rod 22 is driven by the servo motor to rotate about an axis which is parallel to the rotation axis of the inner-groove wheel 21, so that the rotation center of the control rod 22 is located at the eccentric position of the corresponding inner-groove wheel 21. The number of control rods 22 is also two, which are respectively used to drive the corresponding inner-groove wheel 21 to rotate. The control rod 22 has a control protrusion 221. When the control rod 22 rotates, the control protrusion 221 can move from the control port 21c into the control groove 21b, and the control protrusion 221 abuts against the groove wall of the control groove 21b to drive the inner-groove wheel 21 to rotate, so that the inner-groove wheel 21 has a first rotation speed. When the control protrusion 221 moves from the control groove 21b into the control port 21c, the control protrusion 221 is separated from the inner-groove wheel 21, so that the inner-groove wheel 21 is decelerated, so as to control the speed of the powder passing through the powder separation gap 21a, and then when the servo motor drives the control rod 22 to rotate at a constant speed, the rotation speed of the inner-groove wheel 21 can periodically change. On the basis that the rotation directions of the two inner-groove wheels 21 are opposite, the flow rate of the powder passing through the powder separation gap 21a also periodically changes. For example, the two inner-groove wheels 21 can be arranged in a central symmetry, at which time the rotation directions of the servo motors corresponding to the two inner-groove wheels 21 are the same, so that the rotation directions of the two inner-groove wheels 21 are opposite. The two inner-groove wheels 21 can also be arranged in an axial symmetry, at which time the rotation directions of the servo motors corresponding to the two inner-groove wheels 21 are opposite, so that the rotation directions of the two inner-groove wheels 21 are opposite. Figure 2

[0037] Please refer to Figure 1 , Figure 4 and Figure 5 , the melt-blowing assembly 3 has a melting cavity 3a and a discharge port 3b which are in communication with each other, the melting cavity 3a is in communication with the powder separation gap 21a, and the melting cavity 3a is configured to melt the powder fed through the powder separation gap 21a, so that the powder is in a molten state, and the discharge port 3b is configured to spray the powder in a molten state, so as to complete the 3D printing.

[0038] ​When the regulating rod 22 rotates, the regulating protrusion 221 can switch between the regulating groove 21b and the regulating port 21c. When the regulating protrusion 221 moves from the regulating port 21c into the regulating groove 21b, the regulating protrusion 221 can abut against the inner wall of the regulating groove 21b to drive the inner-groove wheel 21 to rotate, so as to accelerate the rotation speed of the inner-groove wheel 21, so that the flow of the powder entering the melting cavity 3a through the powder distribution gap 21a is larger, so as to reduce the possibility that the powder output in a molten state from the discharge port 3b is interrupted. When the regulating protrusion 221 moves from the regulating groove 21b into the regulating port 21c, the regulating protrusion 221 is separated from the inner-groove wheel 21, so as to slow down the inner-groove wheel 21, so that the flow of the powder entering the melting cavity 3a through the powder distribution gap 21a is smaller, so as to reduce the possibility that the powder accumulates in the melting cavity 3a. When the regulating rod 22 rotates at a uniform speed, the rotation speed of the inner-groove wheel 21 can periodically change, so that the powder in the powder distribution cavity 1b can enter the powder distribution gap 21a at a periodically changing flow rate under the driving of the inner-groove wheel 21 and by relying on its own gravity. Reasonable control of the period can improve the matching degree of the powder feeding rate and the powder melting rate, so that the powder is not easy to accumulate in the melting cavity 3a, and the powder in a molten state can also be continuously sprayed from the discharge port 3b, which is beneficial to improve the forming quality of 3D printing. Furthermore, the size of the powder distribution gap 21a can be adjusted to be compatible with powders of various particle sizes, without the need to replace the feeding device as a whole.

[0039] In an embodiment, please refer to Figure 2 The regulating rod 22 also has a friction protrusion 222, and the friction protrusion 222 and the regulating protrusion 221 are arranged opposite to each other along the axial direction of the regulating rod 22. The inner-groove wheel 21 includes a wheel body 211 and a plurality of friction protrusions 212, for example, the number of the friction protrusions 212 is four. The plurality of friction protrusions 212 are arranged at intervals on a first circumference of the wheel body 211, and the regulating groove 21b and the regulating port 21c are formed in the wheel body 211. When the regulating protrusion 221 moves from the regulating groove 21b into the regulating port 21c, the friction protrusion 222 can be in frictional contact with the friction protrusions 212, so that the inner-groove wheel 21 has a second rotation speed, and the second rotation speed is smaller than the first rotation speed, so that when the regulating protrusion 221 is separated from the inner-groove wheel 21, the regulating rod 22 can still drive the inner-groove wheel 21 to rotate at the second rotation speed, at this time, the powder can still enter the melting cavity 3a through the powder distribution gap 21a at a smaller flow rate, so as to reduce the possibility that the powder output in a molten state from the discharge port 3b is interrupted, which is beneficial to improve the forming quality of 3D printing.

[0040] Exemplarily, please refer to Figure 2The regulating groove 21b can be configured as a cross shape, the regulating groove 21b comprises a first groove 21ba and a second groove 21bb arranged vertically, and the friction bump 212 is located between the first groove 21ba and the second groove 21bb, so that the friction bump 222 can be in frictional contact with the friction bump 212 when the regulating protrusion 221 moves from the regulating groove 21b into the regulating port 21c.

[0041] In an embodiment, referring to Figure 2 The wheel body 211 comprises an outer ring 2111 and an inner disc 2112, the inner side wall of the outer ring 2111 is connected with the outer side wall of the inner disc 2112, the regulating groove 21b and the regulating port 21c are formed in the inner disc 2112, the first circumference is located in the inner disc 2112, the rotation center of the regulating rod 22 is located outside the powder separation cavity 1b, and the outer ring 2111 is rotationally and sealingly connected with the outer shell 1 on opposite sides along the axial direction of the outer ring 2111. On the one hand, the possibility of leakage of the powder in the powder separation cavity 1b through the gap between the outer ring 2111 and the outer shell 1 is reduced. On the other hand, the rotation center of the regulating rod 22 is located outside the powder separation cavity 1b, so that the servo motor for driving the regulating rod 22 can also be arranged outside the powder separation cavity 1b, without occupying the volume of the powder separation cavity 1b, thereby reducing the volume of the powder separation cavity 1b as much as possible, which is conducive to concentrating the powder in the powder separation cavity 1b, so that the powder in the powder separation cavity 1b can enter the melting cavity 3a through the powder separation gap 21a as much as possible, thereby improving the accuracy of controlling the flow of the powder into the melting cavity 3a.

[0042] In an embodiment, the air pressure in the powder separation cavity 1b is greater than the atmospheric pressure. Even if there is a certain gap between the inner groove wheel 21 and the outer shell 1, under the guidance of the greater air pressure in the powder separation cavity 1b, on the one hand, it can prevent external impurities from entering the powder separation cavity 1b to pollute the powder; on the other hand, it is conducive to pressing the powder against the inner wall of the powder separation cavity 1b, so that the powder can move along the inner wall of the powder separation cavity 1b better, thereby reducing the possibility of leakage caused by the flying of the powder in the powder separation cavity 1b.

[0043] In an embodiment, referring to Figure 3 , Figure 4 and Figure 6The feeding device includes a stirring member 4. The stirring member 4 is arranged in the feed chamber 1a. The stirring member 4 includes a rotating rod 41 and a spiral blade 42. The rotating rod 41 is rotatably connected to the wall of the feed chamber 1a. For example, one end of the rotating rod 41 along the axial direction is passed through the shell 1 and is connected to the output shaft of the stepper motor. The stepper motor is fixed to the frame of the 3D printer. The rotating rod 41 rotates relative to the shell 1 under the drive of the stepper motor. The rotation speed of the rotating rod 41 can range from 100r / min to 300r / min. The spiral blade 42 is arranged in a spiral shape and extends along the axial direction of the rotating rod 41. The radial size of the spiral blade 42 in the rotating rod 41 gradually changes along the axial direction of the rotating rod 41, so that when the stirring member 4 rotates, the spiral blade 42 can disturb the powder in the feed chamber 1a to reduce the possibility of powder agglomeration and affecting the quality of 3D printing.

[0044] In one embodiment, please refer to Figure 3 、 Figure 4 and Figure 6 , the number of stirring members 4 is multiple, for example, two. Multiple stirring members 4 are arranged at intervals, for example, the distance between two adjacent stirring members 4 can be 5mm to adapt to the particle size of the powder. The two adjacent stirring members 4 are configured to be centrally symmetrical, and the rotation directions of the two adjacent stirring members 4 are opposite. For example, Figure 6 The stirring member 4 on the left side can rotate clockwise, and the stirring member 4 on the right side can rotate counterclockwise. For example, the powder falls into the gap between the spiral blades 42 under the action of gravity. As the two adjacent stirring members 4 rotate, the powder is pushed by the spiral blades 42 to the gap between the two adjacent stirring members 4 to form a relatively stable powder flow. In this process, the two adjacent stirring members 4 with opposite rotation directions can break up the agglomerated powder, and the crushing rate can reach 95%. The flow rate of powder fed into the powder separation chamber 1b is changed by controlling the rotation speed of the stepper motor. For example, when the rotation speed of the stirring member 4 is 200r / min, the powder feeding rate into the powder separation chamber 1b can be stabilized at 2g / s~3g / s, which is conducive to meeting the feeding requirements of the powder separation component 2.

[0045] In one embodiment, the feeding device includes a first cleaning member (not shown). The first cleaning member includes a fixed scraper and an elastic scraper. The fixed scraper and the elastic scraper are both disposed within the outer shell 1 and connected to the inner side of the outer shell 1 to ensure that the inner groove wheel 21 completes a cleaning cycle for each rotation. For example, the main material of the fixed scraper can be configured as a cemented carbide material, and the main material of the elastic scraper can be configured as a polyurethane material. Along the rotation direction of the inner groove wheel 21, the fixed scraper is disposed behind the elastic scraper so that when the inner groove wheel 21 rotates, the fixed scraper contacts the powder remaining on the surface of the inner groove wheel 21 before the elastic scraper. A first cleaning gap is formed between the fixed scraper and the inner groove wheel 21, and a second cleaning gap is formed between the elastic scraper and the inner groove wheel 21. The size of the first cleaning gap is larger than the size of the second cleaning gap. For example, the fixed scraper is positioned at a 45° angle close to the surface of the inner groove wheel 21. The size of the first cleaning gap can be 0.1 mm, which preliminarily scrapes away powder with larger particle sizes (greater than 0.5 mm in diameter) remaining on the surface of the inner groove wheel 21. The hardness of the fixed scraper can be HRC60 to ensure its wear resistance. The elastic scraper can be in close contact with the surface of the inner groove wheel 21 via a spring. The pressure of the spring on the elastic scraper can be 5 N, so that the deformation rate of the elastic scraper is 10%, thereby removing fine powder (less than 0.05 mm in diameter) remaining on the surface of the inner groove wheel 21. The powder residue on the surface of the inner groove wheel 21 after cleaning by the first cleaning member can be less than or equal to 0.01 g / cm 2 The powder cleaned from the surface of the inner groove wheel 21 can fall directly into the melting chamber 3a to reduce the possibility of powder being wasted.

[0046] In one embodiment, the feeding device includes a second cleaning member (not shown). The second cleaning member is configured as a piezoelectric ceramic disc. The piezoelectric ceramic disc is disposed on the rotating shaft of the inner sheave 21 to cause the inner sheave 21 to vibrate at a predetermined frequency. For example, the piezoelectric ceramic disc can be wrapped around the rotating shaft of the inner sheave 21. When the inner sheave 21 rotates, the piezoelectric ceramic disc is synchronously activated, causing the piezoelectric ceramic disc to vibrate at a frequency of 40 kHz, which in turn causes the inner sheave 21 to vibrate at the same frequency. The amplitude of the inner sheave 21 can range from 5 μm to 10 μm, thereby removing powder adhering to the inner sheave 21.

[0047] In one embodiment, please refer to Figure 1 、 Figure 4 and Figure 5The meltblown assembly 3 includes a melter 31 and a nozzle 32. The melter 31 includes an electromagnetic induction coil 311 and a melt shell 312. The melt shell 312 has a melt chamber 3a. The electromagnetic induction coil 311 surrounds the outer periphery of the melt chamber 312. The electromagnetic induction coil 311 can have 500 turns and a wire diameter of 0.5 mm. When the electromagnetic induction coil 311 is energized, the powder in the melt chamber 3a is melted. The nozzle 32 has a discharge port 3b. For example, the powder in this application can be a mixture of polymer powder (main ingredient) and nano-magnetic powder (auxiliary ingredient, such as iron-based powder) in a predetermined ratio (mass ratio of 9:1). The powder enters the melt chamber 3a through the powder separation gap 21a. A 220V AC current is supplied to the electromagnetic induction coil 311, generating an alternating magnetic field with a frequency of 50 kHz, resulting in a magnetic field strength of 0.1 T in the melt chamber 3a. It should be noted that the nanomagnetic powder generates heat due to the eddy current effect in an alternating magnetic field (power adjustable from 300-800W), raising its temperature to the polymer melting point, for example, 180°C-200°C, within 3-5 seconds. This heat indirectly melts the main material through heat conduction. A stirring mechanism with a rotational speed of 50 rpm can also be provided within the melting chamber 3a to ensure uniform melting. The viscosity of the molten powder can be controlled between 500 mPa·s and 1000 mPa·s. It should also be noted that adding nanomagnetic powder to the polymer powder at a predetermined ratio does not affect the quality of 3D printing, but rather improves the powder's performance. The nanomagnetic powder (iron / cobalt / ferrosilicon alloy) is an electromagnetic heating medium, not an impurity. Its function is to generate rapid heat through the eddy current effect, indirectly and evenly heating the polymer powder or low-melting-point metal, avoiding the localized overheating associated with traditional resistance heating. The preset mixing ratio of 1% to 15% by weight represents a trace addition, and once the nanoparticles (e.g., nano-zero-valent iron ≤ 100nm) are uniformly dispersed, they do not alter the particle size distribution of the polymer powder (suitable for powders between 50-200μm). Compared to other related literature, impurity hazards arise from mechanical inclusions (e.g., SiO2) and high oxygen content. Nanomagnetic powders, however, are high-purity metals and feature a self-cleaning design that reduces residual material, preventing the introduction of harmful impurities. Furthermore, nanomagnetic powders can be oriented during melting, enhancing powder density and even improving mechanical properties.

[0048] In one embodiment, please refer to Figure 4 and Figure 5The feeding device includes an electrically connected monitoring component and a controller. The controller is configured to receive the monitoring signal of the monitoring component to adjust the powder separation component 2 and the meltblowing component 3. The monitoring component includes a powder flow sensor 51, a melting temperature sensor 52, a melt viscosity sensor 53 and a nozzle pressure sensor 54. The powder flow sensor 51 is arranged downstream of the powder separation gap 21a to monitor the flow rate of the powder, the melting temperature sensor 52 is arranged in the melting chamber 3a to monitor the temperature in the melting chamber 3a, the melt viscosity sensor 53 is arranged between the melting chamber 3a and the discharge port 3b to monitor the viscosity of the powder in a molten state, and the nozzle pressure sensor 54 is arranged at the discharge port 3b to monitor the pressure of the powder at the discharge port 3b. It should be noted that the residence time of the powder in the melting chamber 3a will affect the uniformity of the powder melting. The relevant device lacks real-time monitoring and feedback of the powder in a molten state, and cannot dynamically adjust the powder feed to match the melting efficiency.

[0049] For example, when the stepper motor receives a pulse signal with a frequency of 500Hz to 2000Hz, it outputs a torque of 2N·m to drive the conical screw and ensure stable rotation of the spiral blade 42 under load. The controller adjusts the speed of the conical screw by varying the pulse frequency. When the powder flow sensor 51 detects a flow deviation of >5% in the powder entering the melting chamber 3a through the powder separation gap 21a, the stepper motor's speed is adjusted synchronously with that of the servo motor (±10 rpm), with a response time of ≤100ms. The servo motor receives an analog signal (0-10V) to drive the control rod 22, with a speed control accuracy of ±0.1 rpm, ensuring a stable flow of powder entering the melting chamber 3a through the powder separation gap 21a. Both the stepper motor and the servo motor are linked by a controller, maintaining a 1.1:1 ratio (redundant design) between the powder flow rate conveyed by the conical screw and the powder flow rate conveyed by the inner groove wheel 21 to prevent powder accumulation or supply interruption.

[0050] The powder flow sensor 51 collects the rate of powder flow every 10 ms with a precision of ±0.01 g / s, and the data is transmitted through the RS485 bus. The melting temperature sensor 52, for example, a K-type thermocouple, monitors the temperature in the melting cavity 3a in real time, with a sampling frequency of 10 Hz and an error of ±1°C. The melting viscosity sensor 53 detects the viscosity of the powder in a molten state by changes in the resonant frequency, with a resolution of 1 mPa·s. The nozzle pressure sensor 54 monitors the pressure at the discharge port 3b, with a range of 0-1 MPa and a precision of ±0.01 MPa. The controller can have a built-in PID algorithm, which is a closed-loop feedback control algorithm that combines proportional (Proportional), integral (Integral), and derivative (Derivative) control, widely used in industrial control, robotics, temperature regulation, and other fields, with the characteristics of simple principle, easy parameter tuning, strong stability, etc. Hereinafter, it will not be described again. The controller with the built-in PID algorithm compares the monitoring values of various sensors with the target values. For example, when the viscosity deviation of the powder in a molten state is >100 mPa·s, adjust the power of the electromagnetic induction coil 311 (±50 W); when the pressure at the discharge port 3b is out of limit (>2 MPa), reduce the rate of powder delivery by the inner groove wheel 21 (±0.5 g / s). When the nozzle pressure sensor 54 detects that the discharge port 3b is blocked (pressure >3 MPa) or the supply is interrupted (flow <0.5 g / s), the controller triggers an alarm and stops, and records the fault location at the same time, which is convenient for maintenance. The controller can also store real-time data (such as temperature, flow, and speed) in each link, with a storage capacity of 1000 entries / hour, to trace the printing process.

[0051] For example, see Figure 4 and Figure 5The shape of the nozzle 32 can be configured as an irregular cone, the diameter of the opening of the nozzle 32 close to the melting cavity 3a can be 15 mm, the diameter of the discharge port 3b of the nozzle 32 can be 0.4 mm-1.2 mm, the taper of the irregularly tapered nozzle 32 can be 30°-60°, so as to reduce the flow assembly of the powder in a molten state. The irregularly tapered nozzle 32 can reduce the pressure of the powder in a molten state from 2 MPa at the opening of the nozzle 32 close to the melting cavity 3a to 0.5 MPa at the discharge port 3b, so as to improve the uniformity of the pressure distribution by 40%, which is beneficial to avoid fluctuations when the powder in a molten state is extruded from the discharge port 3b. The powder in a molten state is extruded from the discharge port 3b under the action of pressure in the nozzle 32, and the inner wall of the nozzle 32 can be coated with a titanium nitride anti-sticking coating to improve the smoothness of the separation of the powder in a molten state from the inner wall of the nozzle 32, thereby making the linear diameter error of the powder in a molten state extruded from the discharge port 3b ≤±0.05 mm, meeting the requirements of the printing layer thickness (0.1 mm-0.3 mm) of FDM 3D printing. A forced air cooling assembly (air speed 5 m / s) can also be provided on the side of the discharge port 3b away from the melting cavity 3a, so that the powder in a molten state extruded from the discharge port 3b can be cooled and solidified relatively quickly (cooling rate 10℃ / ms), which is beneficial to ensure the forming precision of 3D printing.

[0052] The above describes the preferred embodiments of the present application. It should be noted that for those skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should also be considered as the protection scope of the present application.

Claims

1. A 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation, characterized in that: include: a housing having a feed chamber and a powder distribution chamber that are interconnected, wherein the feed chamber is configured to store or feed powder for 3D printing; The powder distributing assembly of claim 1, wherein the inner groove wheel is rotatably connected to the outer shell, and at least a portion of the structure of the inner groove wheel is located in the powder distributing chamber. The number of the inner groove wheels is two, and a powder distributing gap is formed between the two inner groove wheels, and the powder distributing gap is communicated with the powder distributing chamber. The two inner groove wheels rotate in opposite directions, and the inner groove wheels have mutually communicated regulating grooves and regulating ports, and the regulating rod can rotate with an axis parallel to the rotation axis of the inner groove wheel as the rotation axis, and the regulating rod has a regulating protrusion, and when the regulating rod rotates, the regulating protrusion can move from the regulating port into the regulating groove, and the regulating protrusion abuts against the groove wall of the regulating groove, so that the inner groove wheel has a first speed, or the regulating protrusion can move from the regulating groove into the regulating port to disengage the regulating protrusion from the inner groove wheel, so that the inner groove wheel slows down, so as to regulate the speed of the powder passing through the powder distributing gap; The meltblown component has a melting chamber and a discharge port that are interconnected. The melting chamber is connected to the powder separation gap. The melting chamber is configured to melt the powder fed through the powder separation gap so that the powder is in a molten state. The discharge port is configured to spray out the powder in a molten state.

2. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1 is characterized in that: The regulating rod also has a friction protrusion, and the friction protrusion and the regulating protrusion are arranged opposite to each other along the axial direction of the regulating rod. The inner groove wheel includes a wheel body and a plurality of friction protrusions, and the plurality of friction protrusions are arranged at intervals on the first circumference of the wheel body. The regulating groove and the regulating port are formed in the wheel body. When the regulating protrusion moves from the regulating groove to the regulating port, the friction protrusion can frictionally contact with the friction protrusion so that the inner groove wheel has a second rotational speed, which is less than the first rotational speed.

3. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 2 is characterized in that: The wheel body includes an outer ring and an inner disc, the inner wall of the outer ring is connected to the outer wall of the inner disc, the regulating groove and the regulating port are formed on the inner disc, the first circumference is located on the inner disc, the rotation center of the regulating rod is located on the outside of the powder dividing chamber, and the outer ring is rotatably sealed with the outer shell on both opposite sides along its own axial direction.

4. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1 is characterized in that: The air pressure in the powder separation chamber is greater than atmospheric pressure.

5. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1 is characterized in that: The feeding device includes a stirring member, which is arranged in the feeding chamber. The stirring member includes a rotating rod and a spiral blade. The rotating rod is rotatably connected to the wall of the feeding chamber. The spiral blade is arranged in a spiral shape and extends along the axial direction of the rotating rod. The radial size of the spiral blade in the rotating rod gradually changes along the axial direction of the rotating rod.

6. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 5 is characterized in that: There are multiple stirring members, and the multiple stirring members are arranged at intervals. Two adjacent stirring members are configured to be centrally symmetrical, and the rotation directions of the two adjacent stirring members are opposite.

7. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1 is characterized in that: The feeding device includes a first cleaning member, which includes a fixed scraper and an elastic scraper. The fixed scraper and the elastic scraper are both arranged in the outer shell. Along the rotation direction of the inner groove wheel, the fixed scraper is arranged behind the elastic scraper. A first cleaning gap is formed between the fixed scraper and the inner groove wheel, and a second cleaning gap is formed between the elastic scraper and the inner groove wheel. The size of the first cleaning gap is larger than the size of the second cleaning gap.

8. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1 is characterized in that: The feeding device includes a second cleaning member, which is configured as a piezoelectric ceramic piece. The piezoelectric ceramic piece is arranged on the rotating shaft of the inner groove wheel to make the inner groove wheel vibrate at a preset frequency.

9. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1 is characterized in that: The meltblown assembly includes a melting part and a nozzle. The melting part includes an electromagnetic induction coil and a melting shell. The melting shell has the melting cavity. The electromagnetic induction coil surrounds the outer periphery of the melting shell so that the powder in the melting cavity is in a molten state. The nozzle has the discharge port.

10. The 3D printing powder feeding device based on non-uniform speed inner groove wheel powder separation according to claim 1, characterized in that: The feeding device includes an electrically connected monitoring component and a controller, and the controller is configured to receive a monitoring signal from the monitoring component to adjust the powder separation component and the meltblowing component. The monitoring component includes a powder flow sensor, a melting temperature sensor, a melt viscosity sensor and a nozzle pressure sensor. The powder flow sensor is arranged downstream of the powder separation gap to monitor the flow rate of the powder, the melt temperature sensor is arranged in the melting chamber to monitor the temperature in the melting chamber, the melt viscosity sensor is arranged between the melting chamber and the discharge port to monitor the viscosity of the powder in a molten state, and the nozzle pressure sensor is arranged at the discharge port to monitor the pressure of the powder at the discharge port.

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