A coaxial powder feeding, stirring, friction additive manufacturing and grinding device

Abstract

This invention provides a coaxial powder feeding friction stirring additive manufacturing and grinding device, comprising: a feeding device including a feed pipe connected to the feed inlet of the cylinder of the feeding module; a friction stirring module including a friction stirring rod and a friction stirring drive mechanism; a feeding module including a feeding screw drive mechanism, a feeding screw, and a cylinder, wherein the friction stirring rod and the feeding screw are coaxially arranged and rotatably connected by bearings, the end of the friction stirring rod is located outside the feeding screw and extends into the bottom of the cylinder and into the cavity of the opening and closing control device; an opening and closing control device disposed below the cylinder, including a temperature sensor and an opening and closing mechanism; a replaceable discharge port connected below the opening and closing control device; and a grinding device and the lifting device fixed on a lifting device. This invention achieves integrated and intelligent control of the entire process from powder feeding, frictional heating, extrusion of clay-plastic materials to simultaneous grinding.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, specifically to a coaxial powder feeding, stirring, friction additive manufacturing and polishing device. Background Technology

[0002] Additive manufacturing technology, as a key technology in high-end manufacturing, faces increasingly stringent requirements for the performance, precision, and forming efficiency of structural components in industries such as aerospace and automotive manufacturing. Lightweight alloy materials (such as aluminum and magnesium alloys) are widely used in these fields due to their advantages of light weight and high strength; however, melt-processing additive manufacturing techniques for lightweight alloys are prone to problems such as deformation and cracking. Friction stir additive manufacturing, as a solid-state forming technology, offers advantages such as low heat input, low residual stress in parts, and excellent material mechanical properties, making it an important technological direction for the efficient forming of lightweight alloys.

[0003] Currently, the application scope and processing efficiency of friction stir additive manufacturing technology are limited by factors such as raw material form, process connection, and equipment control. The limitations of traditional raw material forms (bars, wires) lead to poor material adaptability, process separation results in insufficient processing accuracy and efficiency, and low equipment intelligence makes it difficult to guarantee processing stability. These problems restrict the further promotion of friction stir additive manufacturing technology.

[0004] Currently, most mainstream friction stir additive manufacturing (FSM) devices use rods or wires as forming materials. Devices using rods require high-rigidity equipment to apply axial pressure to the rod, pushing it into the processing area. The material is then shaped using the friction of the stirring rod. However, the rod composition and specifications are fixed, making it impossible to adjust the proportions. Furthermore, uneven axial pressure can easily cause feeding jams when processing complex, irregularly shaped parts. Devices using wires feed the wire into the processing area via a wire feeding mechanism. The wire is plasticized and shaped under frictional heat. However, the wire feeding process is prone to interruptions, requiring frequent shutdowns to replace the wire rolls, severely impacting processing continuity. Additionally, the wire is susceptible to overheating due to excessive frictional heat in certain areas.

[0005] Devices using powder as raw material typically feed the powder between a stirring blade and a substrate for stirring and friction. The powder is prone to splashing in the open space, and the required downward pressure can easily lead to the collapse of the formed structure and a decrease in performance. Patent CN115178855B discloses a coaxial powder-feeding friction stir additive manufacturing head, which has the following problems: 1) Insufficient flexibility in powder feeding rate. When processing parts of different thicknesses and materials, the powder feeding amount needs to be adjusted to match the forming rate. It is impossible to precisely control the powder feeding rate by changing the powder feeding power parameters in real time, easily leading to a mismatch between powder supply and friction forming rhythm, resulting in an excessively thick or thin deposition layer, affecting forming accuracy and quality; 2) Risk of powder accumulation and overflow in the recessed area. The recessed area is designed as a circular groove around the stirring pin, which can prevent powder splashing to some extent, but when the stirring pin rotates at high speed (depending on...),... During the high-speed rotation of the machining head driven by the rotary drive shaft, the powder in the recess is prone to accumulate on the tank wall due to centrifugal force. If the powder feeding rate is slightly higher than the friction consumption rate, the powder is likely to overflow from the edge of the recess to the lower end face of the shaft shoulder section. This not only wastes the powder but may also cause the overflowing powder to adhere to the surface of the already formed deposited layer, interfering with the forming and adhesion of subsequent layers and increasing surface roughness. 3) There is a potential downward pressure effect on the already formed structure. During the processing, in order to ensure that the powder undergoes sufficient frictional plastic deformation in the recess, an axial forging force needs to be applied by the rotary drive axial machining head. This force is transmitted to the recess and the already formed structure below through the shaft shoulder section. Although the downward pressure is reduced compared to the traditional open space powder feeding method, for thin-walled, slender and other fragile structural parts, the continuous axial forging force may still cause slight deformation or collapse of the already formed structure. Especially after multi-layer deposition, the pressure accumulated on the lower structure is superimposed, which can easily cause deviations in the overall structural dimensions. Patent CN118305417A discloses a separate spiral feeding friction welding and additive manufacturing device and method with adjustable powder feeding rate. However, it has the following problems: Powder blockage is prone to occur at the connection between the powder feeding channel and the storage chamber, especially when the powder particle size is large or the powder contains slight viscosity. It is easy to clump at the inlet, causing blockage of the powder feeding channel, requiring machine shutdown for cleaning, interrupting the continuous processing, and reducing production efficiency; The powder feeding stability is poor when the clutch mechanism is engaged. At the moment of engagement of the separate rotating head, due to the mechanical gap and alignment error between the two tooth surfaces, meshing impact is easy to occur, causing a brief fluctuation in the speed of the spiral powder feeding channel. This fluctuation will directly cause the powder feeding rate to be fast and slow, making the amount of powder entering the storage chamber unstable, which in turn leads to uneven powder extrusion from the outlet, resulting in density differences in the deposition layer and affecting the mechanical properties of the component; Powder forming at the outlet ring is easily interfered with. The outlet ring is used to collect powder and provide friction forming for the conical stirring head. The gap between the ring and the conical stirring head is fixed. When processing powders of different materials, the fixed gap cannot be adapted to the frictional flow characteristics of different powders; the structural adjustment is complicated when switching between welding and additive manufacturing, and the switching steps when switching the device to the friction stir welding mode are cumbersome and time-consuming, which reduces the efficiency of multi-process continuous processing.Patent CN119328286A discloses a coaxial powder feeding friction stir additive manufacturing process and apparatus, but it has the following problems: poor coordination between the vibratory feeder and the screw, which easily leads to fluctuations in powder supply. When the powder feeding rate of the vibratory feeder is slightly higher than the screw conveying rate, powder easily accumulates in the barrel, causing the cavity between the screw and the inner wall of the barrel to be overfilled, increasing the screw rotation resistance, and even causing the screw to jam. If the powder feeding rate of the vibratory feeder is lower than the screw conveying rate, the powder supply in the barrel is prone to interruption, resulting in insufficient powder at the gap between the tool and the substrate, and voids or breaks in the deposition layer, affecting the continuity of forming. There is a risk of lag in the power transmission system. When the speed of motor A is adjusted to adapt to different powder friction requirements, the elasticity of the synchronous belt may be affected. Deformation causes a lag in power transmission, preventing the tool rotation speed from responding promptly to the parameter adjustments of motor A. This leads to a short-term mismatch between the tool rotation speed and the powder delivery rate, affecting the stability of powder frictional heating and resulting in uneven microstructure of the deposited layer. Furthermore, open-space powder feeding is prone to splashing, and excessive downward pressure affects forming quality and structural stability. During the high-speed rotation and stirring friction of the tool, powder that does not participate in frictional forming in time is easily affected by rotating airflow and mechanical disturbances, splashing outwards. This not only wastes powder material but may also cause splashed powder to adhere to the surface of the formed structure, interfering with the deposition and bonding of subsequent layers. Simultaneously, to ensure that the powder in the open space can fully plastically deform and tightly bond with the substrate and the formed layers, a large downward pressure is required. Excessive downward pressure can easily cause the collapse of fragile structures such as thin-walled or hollowed-out structures, or generate excessive compressive stress within the deposited layer, leading to defects such as cracking and deformation, significantly reducing the mechanical properties and dimensional accuracy of the formed part.

[0006] In addition, existing friction stir additive manufacturing equipment requires the parts to be transferred to a special grinding equipment for secondary grinding after the parts are additively formed. During the processing, the parts need to be re-clamped and positioned, which not only prolongs the production cycle, but also easily leads to a decrease in the accuracy of the parts due to the deviation of the positioning reference.

[0007] Therefore, existing friction stir additive manufacturing equipment has the following drawbacks:

[0008] (1) Poor raw material compatibility: With rods and wires as raw materials, the composition and specifications are fixed, and the material ratio cannot be flexibly adjusted, making it difficult to achieve the forming of multi-element alloys and functional gradient materials.

[0009] (2) Insufficient processing continuity: bar feeding relies on high-rigidity equipment, and processing complex irregular parts is prone to jamming; wire connection is prone to interruption, requiring frequent machine stoppages to change materials, which affects production efficiency.

[0010] (3) Poor automation and controllability: lack of real-time monitoring of surplus materials, material supply is prone to accumulation or insufficiency; temperature and discharge are not linked for control, and cannot be dynamically adjusted according to processing status.

[0011] (4) Low forming stability and efficiency: The material has a lot of contact with the outside world, resulting in a large heat loss and unstable forming temperature; the powder is easy to rotate with the friction rod, which reduces the efficiency of frictional heat generation; the discharge port is mostly through the pressure of the formed structure, which can easily lead to collapse and changes in structural performance.

[0012] Currently, there are no publicly available documents or patents mentioning a friction stir additive manufacturing device that integrates a coaxial powder feeding structure, a stirring friction unit, and a grinding unit, and achieves intelligent control. Summary of the Invention

[0013] The technical problem to be solved by the present invention is to provide a coaxial powder feeding stirring friction additive manufacturing and grinding device, which solves a series of problems in the prior art, such as poor raw material compatibility, easy feeding jamming, process separation, low level of automation, large heat loss, and easy collapse of the formed structure under pressure.

[0014] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0015] The coaxial powder feeding friction stirring additive manufacturing and grinding apparatus of the present invention includes a feeding device, a friction stirring module, a feeding module, an opening and closing control device, a replaceable discharge port, a lifting device, a grinding device, and a housing. The feeding device includes a feeding pipe connected to the inlet of the feeding module's cylinder for feeding powder into the cylinder. The friction stirring module includes a friction stirring rod and a friction stirring drive mechanism. The feeding module includes a feeding screw drive mechanism, a feeding screw, and a cylinder. The threaded portion of the feeding screw is located inside the cylinder, and the feeding screw is driven by the feeding screw drive mechanism to feed powder from the inlet to the end of the friction stirring rod. The mixing friction rod and the feeding screw are coaxially arranged and connected relative to each other by bearings. The end of the mixing friction rod is located outside the feeding screw and extends into the bottom of the cylinder and further extends into the internal cavity of the opening and closing control device. The opening and closing control device is located below the cylinder and includes a temperature sensor and an opening and closing mechanism. The temperature sensor is used to detect the temperature inside the device. When the temperature reaches a predetermined value, it controls the opening and closing motor to drive the opening and closing mechanism to open the discharge channel. A replaceable discharge port is connected below the opening and closing control device. The grinding device is fixed on the lifting device, and the lifting device is installed on the outer wall of the lower part of the outer shell.

[0016] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the feeding device also includes a millimeter-wave radar. The millimeter-wave radar is installed inside the upper cover of the cylinder and is used to monitor the height of the remaining material inside the cylinder in real time and adjust the feeding rate.

[0017] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the friction stirring drive mechanism includes a friction stirring rod drive motor, a friction stirring rod drive gear, and a friction stirring rod gear. The friction stirring rod drive motor drives the friction stirring rod drive gear to rotate, which in turn drives the friction stirring rod gear to rotate, ultimately causing the friction stirring rod fixed to the friction stirring rod gear to rotate.

[0018] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the stirring friction rod is connected to the inner ring of the bearing and the feeding screw is connected to the outer ring of the bearing; the diameter of the end of the stirring friction rod is larger than the diameter of the rest of the stirring friction rod, and the rod wall at the end of the stirring friction rod is provided with knurling, and a semi-circular protrusion is provided on the bottom end face of the end of the stirring friction rod.

[0019] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the feeding screw is connected to the top cover of the cylinder through the feeding screw bearing, so that the feeding screw can rotate inside the cylinder.

[0020] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the opening and closing mechanism includes an upper shell of the opening and closing control mechanism, a lower shell of the opening and closing control mechanism, a connecting column, an intermediate pad, an upper plate of the opening and closing mechanism, multiple rotating blades, a chassis of the opening and closing mechanism, a chassis gear of the opening and closing mechanism, and a transmission gear of the chassis of the opening and closing mechanism. The opening and closing motor drives the transmission gear of the chassis of the opening and closing mechanism to rotate, thereby driving the chassis gear of the opening and closing mechanism and the chassis of the opening and closing mechanism fixed thereto to rotate, thereby driving multiple rotating blades to rotate along their tracks and opening the discharge channel.

[0021] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the replaceable discharge port is provided with bolt holes and connected to the opening and closing control device through bolts, and the replaceable discharge port can be replaced with discharge ports of different diameters.

[0022] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the lifting device includes a base plate, a screw drive motor, a ball screw, a guide rail slider, a guide rail, and a slide table. The base plate is installed on the outer wall of the lower part of the housing. The guide rail and the ball screw are both fixed on the base plate. The ball screw is fixedly connected to the slide table. The grinding device is installed on the slide table. The two sides of the slide table are connected to the guide rail slider. The guide rail slider is sleeved on two parallel guide rails, and the guide rails are provided with limit blocks at both ends.

[0023] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the grinding device includes a connecting component, a top beam, a worm gear and rack fixing groove, a worm base, a worm, a rack, a rack slide groove, a grinding motor, and a grinding wheel. The top beam is fixed on the connecting component, the worm gear and rack fixing groove is fixed on the top beam, the worm base and the rack slide groove are both fixed on the worm gear and rack fixing groove, the worm is fixed on the worm base and meshes with the rack in the rack slide groove, and rotating the worm can drive the rack to move laterally along the rack slide groove.

[0024] Optionally, in the above-mentioned coaxial powder feeding friction stirring additive manufacturing and grinding device, the outer shell includes an upper cover, a side cover, a lower cover, an upper clamping plate, and a lower clamping plate. The side cover connects the upper cover and the lower cover. The upper clamping plate and the lower clamping plate are located between the upper cover and the lower cover and are fixed on the side cover. The upper cover has a hole for the feed pipe to pass through, and the lower cover has a hole for the cylinder to pass through.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] Enhanced material adaptability: Breaking through the limitations of raw material form, adopting a coaxial powder feeding structure, it achieves flexible material proportioning, adapting to the forming needs of multi-element alloys and functional gradient materials, and solving the problem of fixed raw material proportions in traditional methods;

[0027] Higher processing continuity: Powder can be continuously fed without frequent machine stoppages for material change. The feeding screw does not require high-rigidity equipment to provide axial pressure, avoiding jamming in the processing of complex irregular parts, improving production efficiency, realizing continuous feeding and process integration, and solving the problems of feeding jamming and connection interruption.

[0028] Superior processing accuracy and efficiency: Additive manufacturing and grinding are carried out simultaneously, eliminating secondary processing steps and avoiding positioning errors. Simultaneous completion of additive manufacturing and grinding improves processing continuity and accuracy. Furthermore, the grinding position can be flexibly adjusted to adapt to parts of different sizes, ensuring accuracy.

[0029] Improved automation and stability: The equipment's intelligence and automation levels have been enhanced. Millimeter-wave radar monitors the residual material height in real time to regulate the feeding rate. Temperature sensors and opening / closing control devices work together to control the discharge. Real-time monitoring of residual material and temperature allows for dynamic regulation of feeding and discharging, ensuring processing stability and reducing human intervention. The feeding screw also compacts the powder inside the cylinder, effectively improving friction efficiency and preventing a decrease in frictional heat generation efficiency caused by the powder rotating with the friction rod. The sealed environment reduces heat loss, and compacting the powder improves friction efficiency, ensuring forming quality.

[0030] The process employs friction stirring to generate heat and a closed forming environment: the powder material undergoes a transformation to a clay-like state within a sealed space at the bottom of the cylinder and above the opening and closing control device. This reduces contact with outside air, effectively minimizing heat loss, ensuring stable forming temperature, and thus improving additive manufacturing efficiency and forming quality. The friction stirring process, completed within the sealed space formed by the bottom of the cylinder and the upper part of the opening and closing control device, significantly reduces the downward pressure on the formed structure from the discharge port, preventing collapse due to excessive stress, ensuring the integrity, dimensional accuracy, and mechanical properties of the formed parts, and guaranteeing forming quality. Attached Figure Description

[0031] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.

[0032] Figure 1 This is a schematic diagram of the external overall structure of the coaxial powder feeding, stirring, friction additive manufacturing and polishing device of the present invention;

[0033] Figure 2 This is a cross-sectional view of the feeding device of the present invention;

[0034] Figure 3 This is a schematic diagram of the stirring friction module and the feeding module of the device of the present invention;

[0035] Figure 4 This is a cross-sectional view of the stirring friction module of the device of the present invention;

[0036] Figure 5 This is a partial cross-sectional view of the upper part of the stirring friction module of the device of the present invention;

[0037] Figure 6 This is a partial cross-sectional view of the lower part of the stirring friction module of the device of the present invention;

[0038] Figure 7 This is a schematic diagram of the stirring friction rod of the device of the present invention;

[0039] Figure 8 This is a cross-sectional view of the feeding module of the device of the present invention;

[0040] Figure 9 This is a schematic diagram of the opening and closing control device of the present invention;

[0041] Figure 10 This is an exploded view of the opening and closing control device of the present invention;

[0042] Figure 11 This is a cross-sectional view of the opening and closing control device of the present invention;

[0043] Figure 12This is a schematic diagram of the replaceable discharge port of the device of the present invention;

[0044] Figure 13 This is a schematic diagram of the lifting device of the present invention;

[0045] Figure 14 This is a partial structural schematic diagram of the lifting device of the present invention;

[0046] Figure 15 This is a schematic diagram of the grinding device of the present invention;

[0047] Figure 16 This is a partial structural diagram of the grinding device of the present invention;

[0048] Figure 17 This is a structural diagram of the outer casing and clamping components of the device of the present invention.

[0049] Numbers in the diagram: 1-Feeding device; 101-Feeding pipe; 102-Millimeter-wave radar; 2-Friction stirring module; 201-Friction stirring rod drive motor; 202-Friction stirring rod drive gear; 203-Friction stirring rod gear; 204-Friction stirring rod; 2041-End; 2042-Knurling; 2043-Semi-circular protrusion; 205-Friction stirring rod bearing; 3-Feeding module; 301-Feeding screw drive motor; 3 02-Feeding screw drive gear; 303-Feeding screw gear; 304-Feeding screw; 305-Feeding screw bearing; 306-Top cover of cylinder; 307-Cylinder; 4-Opening and closing control device; 401-Upper housing of opening and closing mechanism; 402-Lower housing of opening and closing mechanism; 403-Connecting column; 404-Intermediate pad; 405-Upper plate of opening and closing mechanism; 406-Rotating blade; 407-Base of opening and closing mechanism; 408-Base of opening and closing mechanism Disc gear; 409-Opening and closing mechanism chassis transmission gear; 410-Opening and closing motor; 411-Temperature sensor; 5-Replaceable discharge port; 501-Bolt hole; 6-Lifting device; 601-Screw drive motor; 602-Screw fixing seat; 603-Base plate; 604-Guide rail; 605-Limit block; 606-Ball screw; 607-Screw support seat; 608-Guide rail slider; 609-Screw nut; 610-Slide table; 7- Grinding device; 701-Connecting component; 702-Top beam; 703-Worm and rack fixing groove; 704-Worm base; 705-Worm; 706-Rack; 707-Rack slide groove; 708-Motor housing; 709-Motor housing cover; 710-Grinding motor; 711-Grinding wheel; 8-Housing; 801-Housing top cover; 802-Housing side; 803-Housing bottom cover; 804-Upper clamping plate; 805-Lower clamping plate. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0051] The coaxial powder feeding, stirring, friction additive manufacturing and grinding device of the present invention realizes the integrated and intelligent control of the entire process from powder feeding, friction heating, extrusion of clay-plastic materials to synchronous grinding.

[0052] like Figure 1 and Figure 3 As shown, the coaxial powder feeding friction stirring additive manufacturing and on-the-fly grinding apparatus of the present invention includes a feeding device 1, a friction stirring module 2, a feeding module 3, an opening and closing control device 4, a replaceable discharge port 5, a lifting device 6, a grinding device 7, and a housing 8. Wherein, as... Figure 2 As shown, the feeding device 1 includes a feeding pipe 101 and a millimeter-wave radar 102. The feeding pipe 101 passes through the opening of the outer casing cover 801 and connects to the feeding port of the cylinder cover 306 of the feeding module 3. The powder material is fed into the cylinder 307 of the feeding module 3 through the feeding pipe 101. The millimeter-wave radar 102 is installed inside the cylinder cover 306 and is used to monitor the height of the remaining material in the cylinder 307 in real time and feed back the data. This allows for precise control of the feeding rate based on the expected height, ensuring that the powder supply dynamically matches the forming requirements and avoiding material accumulation or insufficient supply.

[0053] like Figures 3-6 As shown, the friction stirring module 2 includes a friction stirring rod 204 and a friction stirring drive mechanism for driving the friction stirring rod 204 to rotate. The friction stirring module 2 is used to generate heat through friction stirring to transform the material into a clay-like state. The friction stirring drive mechanism includes a friction stirring rod drive motor 201, a friction stirring rod drive gear 202, a friction stirring rod gear 203, and a friction stirring rod bearing 205. Specifically, the friction stirring rod drive motor 201 drives the friction stirring rod drive gear 202 to rotate, which in turn drives the meshing friction stirring rod gear 203 to rotate, ultimately causing the friction stirring rod 204, which is fixed to the friction stirring rod gear 203, to rotate.

[0054] like Figure 4 , Figure 6 and Figure 7As shown, the stirring friction rod 204 has a thicker end 2041, meaning the diameter of the end 2041 is larger than the diameter of the rest of the stirring friction rod 204. The thicker end 2041 of the stirring friction rod 204 extends into the bottom of the cylinder 3 and further into the internal cavity of the opening and closing control device 4. The rod wall of the end 2041 is provided with knurling 2042, and the bottom end face of the end 2041 is provided with several semi-circular protrusions 2043, thereby increasing the frictional contact area with the powder and improving the efficiency of stirring friction heat generation. Under the stirring friction action of the stirring friction rod 204, the powder heats up and becomes a clay-like state. The process of the powder becoming a clay-like state is mainly completed in the sealed space at the bottom of the cylinder 307 and the upper part of the opening and closing control device 4, resulting in minimal heat loss and stable temperature.

[0055] like Figure 3 and Figure 8 As shown, the feeding module 3 includes a feeding screw drive mechanism, a feeding screw 304, a cylinder cover 306, and a cylinder 307. The feeding module 3 is responsible for conveying the powder and compacting it under downward pressure. The feeding screw 304 is connected to the cylinder cover 306 of the cylinder 307 via a feeding screw bearing 305, allowing the feeding screw 304 to rotate within the cylinder 307. The threaded portion of the feeding screw 304 is located inside the cylinder 307. The feeding screw drive mechanism includes a feeding screw drive motor 301, a feeding screw drive gear 302, and a feeding screw gear 303. The feeding screw drive motor 301 drives the feeding screw drive gear 302 to rotate, which in turn drives the feeding screw gear 303 and the feeding screw 304 fixed thereto to rotate.

[0056] like Figure 4 and Figure 5 As shown, the stirring friction rod 204 and the feeding screw 304 are coaxially arranged and connected by bearings. Specifically, the stirring friction rod 204 is rotatably connected to the feeding screw 304 via two upper and lower stirring friction rod bearings 205, allowing them to rotate relative to each other. The stirring friction rod 204 is connected to the inner ring of the stirring friction rod bearing 205, and the feeding screw 304 is connected to the outer ring of the stirring friction rod bearing 205. A portion of the stirring friction rod 204 is located inside the feeding screw 304, meaning the stirring friction rod 204 also has a portion extending outside the feeding screw 304, such as the upper part of the stirring friction rod 204 extending beyond the feeding screw 304 and the thicker end 2041 at the lower part of the stirring friction rod 204. Figure 4 and 5 As shown. The thicker end 2041 of the stirring friction rod 204 is located outside the feeding screw 304 and extends into the bottom of the cylinder 3 and further into the internal cavity of the opening and closing control device 4, as shown. Figure 4As shown, the powder material undergoes a transformation process from a stirred, friction-generated, and heated state to a clay-like state within a sealed space formed by the bottom of the cylinder and the upper part of the opening and closing control device. This reduces contact with outside air, effectively reduces heat loss, ensures the stability of the forming temperature, and thus improves the efficiency and forming quality of additive manufacturing.

[0057] After the powder is fed into the cylinder 307 by the feeding device 1, it is fed along the screw thread to the end area of ​​the stirring friction rod 204 by the downward pressure generated by the rotation of the feeding screw 304. The powder becomes dense due to the downward pressure of the feeding screw 304.

[0058] like Figure 9 , Figure 10 and Figure 11 As shown, the opening and closing control device 4 is located below the cylinder 307. The opening and closing control device 4 includes an upper outer shell 401, a lower outer shell 402, a connecting column 403, an intermediate pad 404, an upper plate 405, several rotating blades 406, a base 407, a base gear 408, a transmission gear 409, an opening and closing motor 410, and a temperature sensor 411. The opening and closing control device 4 is used to control the opening and closing of the discharge channel connected to the replaceable discharge port 5 according to the temperature inside the device. The temperature sensor 411 monitors the temperature inside the device (especially in the area where the clay-plastic material is formed) in real time. After the temperature sensor 411 detects that the temperature inside the device has reached a predetermined value, it sends a signal to the opening and closing motor 410. The opening and closing motor 410 starts and drives the transmission gear 409 of the opening and closing mechanism chassis to rotate, which in turn drives the gear 408 of the opening and closing mechanism chassis and the opening and closing mechanism chassis 407 fixed thereto to rotate. Several rotating blades 406 rotate along their track, opening the discharge channel. Under the continuous pressure of the feeding screw 304, the clay-like material flows into the replaceable discharge port 5 below through the opened discharge channel.

[0059] The replaceable discharge port 5 is located below the opening and closing control device 4, and the clay-plastic material flows out from the replaceable discharge port 5 to form additives. For example... Figure 12 As shown, the replaceable discharge port 5 is provided with several bolt holes 501, and the replaceable discharge port 5 passes through several bolt holes 501 ( Figure 12 It is connected to the opening and closing control device 4. The replaceable discharge port 5 can be changed to a different discharge diameter according to the width of additive manufacturing.

[0060] The lifting device 6 is installed on the outer wall of the lower part of the housing 8, such as Figure 1 As shown. Lifting device 6, as... Figure 13 and Figure 14As shown, the device includes a lead screw drive motor 601, a lead screw fixing seat 602, a base plate 603, a guide rail 604, a limit block 605, a ball screw 606, a lead screw support seat 607, a guide rail slider 608, a lead screw nut 609, a slide table 610, and a lifting device 6 for adjusting the height of the grinding device 7, i.e., its vertical position. The base plate 603 of the lifting device 6 is mounted on the lower outer wall of the housing 8. The guide rail 604 and the ball screw 606 are both fixed to the base plate 603. The ball screw 606 is fixed to the base plate 603 via the lead screw fixing seat 602 and the lead screw support seat 607. The lead screw nut 609 on the ball screw 606 is fixedly connected to the slide table 610. The slide table 610 is connected to four guide rail sliders 608 on both sides, and the guide rail sliders 608 are sleeved on two parallel guide rails 604. The lead screw drive motor 601 drives the ball screw 606 to rotate. When the ball screw 606 rotates, the lead screw nut 609 drives the slide table 610 and the grinding device 7 mounted on the slide table 610 to move up and down along the guide rail 604. Limit blocks 605 are provided at both ends of the guide rail 604 to prevent the slide table 610 from overtraveling.

[0061] Grinding device 7, such as Figure 15 and Figure 16 As shown, the assembly includes a connecting component 701, a top beam 702, a worm gear and rack fixing groove 703, a worm base 704, a worm 705, a rack 706, a rack slide groove 707, a motor housing 708, a motor housing cover 709, a grinding motor 710, and a grinding wheel 711, as well as a grinding device 7 for instant grinding of the newly formed additive structure. The grinding device 7 is bolted to the slide table 610 of the lifting device 6 via the connecting component 701, and the top beam 702 is bolted to the connecting component 701. The worm gear and rack fixing groove 703 is fixed to the top beam 702, and both the worm base 704 and the rack slide groove 707 are fixed to the worm gear and rack fixing groove 703. The worm 705 is fixed to the worm base 704 and meshes with the rack 706. Rotating the worm gear 705 drives the rack 706 to move laterally along the rack groove 707, thereby precisely adjusting the grinding wheel 711's grinding position in the horizontal direction. The grinding motor 710 is fixed within the sealed cavity formed by the motor housing 708 and the motor housing cover 709, providing a sealed protection. The output shaft of the grinding motor 710 is fixedly connected to the grinding wheel 711 and directly drives the grinding wheel 711 to rotate at high speed. The surface of the grinding wheel 711 is coated with diamond abrasive grains, and different grit sizes of diamond abrasive grains can be selected according to the final surface grinding precision requirements.

[0062] Casing 8, such as Figure 17As shown, the device includes an upper outer cover 801, outer cover sides 802, outer cover bottom cover 803, upper clamping plate 804, and lower clamping plate 805, and the outer casing 8 forms the overall support and protection structure of the device. The upper outer cover 801 has two holes for two feed pipes 101 to pass through. The lower outer cover 803 has a hole for the cylinder to pass through. The two outer cover sides 802 connect the upper outer cover 801 and the lower outer cover 803, forming a closed or semi-closed box that provides enclosed protection for the main shaft inside. The upper clamping plate 804 and the lower clamping plate 805 are located between the upper outer cover 801 and the lower outer cover 803 and are fixed to the two outer cover sides 802, used to clamp and fix the internal shaft.

[0063] The coaxial powder feeding, stirring, friction additive manufacturing, and on-the-fly grinding device of this invention, combined with the requirements of intelligent monitoring and linkage control, constructs the following intelligent feeding control formula and intelligent discharging control formula to achieve dynamic matching of material supply and forming requirements, and precise linkage between temperature and discharging status. This realizes integrated and intelligent control of the entire process from powder feeding, friction heating, extrusion of clay-plastic materials to simultaneous grinding. The intelligent control formula is as follows:

[0064] I. Intelligent Feed Control Formula

[0065] Among them, the intelligent feeding control uses the residual material height monitored in real time by millimeter-wave radar as the core input, and combines it with the additive forming rate (which is related to the target size of the part and the friction stirring efficiency) to dynamically adjust the feeding rate and avoid material accumulation or insufficient supply. The core parameters are defined in Table 1 below.

[0066] Table 1 Definition of Core Parameters in the Intelligent Feed Control Formula

[0067] Parameter symbol Parameter name unit Definitions Real-time residual material height at time t mm The millimeter-wave radar 102 in the feeding device 1 collects data in real time, reflecting the current powder material inventory inside the cylinder 307. Set residual material height mm The optimal residual material baseline value (to avoid empty or full silos) is determined based on the cylinder volume and feeding response delay, and is typically taken as 30%-50% of the effective cylinder height. Additive forming rate at time t mm³ / s The volume of powder required for forming per unit time is calculated based on the diameter of the replaceable discharge port 5, the thickness of the forming layer of the part, and the moving speed of the device. Powder loose density g / mm³ The inherent physical properties of powder materials need to be determined in advance based on the specific material (such as aluminum alloy powder, magnesium alloy powder). Feed screw efficiency — The effective coefficient of powder conveying by the 304 feeding screw is related to the screw pitch, rotational speed, and powder flowability, and its value ranges from 0.85 to 0.95. Feed screw diameter mm The nominal diameter of the feeding screw 304 in feeding module 3 Feed screw pitch mm Thread pitch of the 304 feed screw Target rotational speed of the feed screw at time t r / s The key output parameters that need to be adjusted determine the feeding rate. Residual material height adjustment coefficient — The proportional adjustment coefficient is dynamically corrected based on the magnitude of the remaining material deviation, with a value range of 0.5-1.2 (the larger the deviation, the larger the coefficient).

[0068] Formula for target rotational speed of the feed screw (core control formula)

[0069] The feeding rate must simultaneously meet the requirements of "compensating for excess material deviation" and "matching forming requirements", as shown in the following formula:

[0070]

[0071] The first part on the right ( ): Item for correcting for material deviation. When When there is insufficient residual material, this item is positive, and the screw speed is increased to replenish the residual material; when When there is excessive material residue, this item is negative, so the screw speed is reduced to decrease the feed rate and avoid accumulation. The second part on the right: Forming requirement matching item, based on the real-time forming rate. Calculate the base rotation speed required for the current forming process to ensure that the powder supply is consistent with the part forming rhythm.

[0072] Additive forming rate correlation formula

[0073] The calculation needs to be based on the actual operating parameters of the device. The formula is as follows:

[0074]

[0075] in: The inner diameter (mm) of the interchangeable discharge port 5 can be selected according to the forming width of the part (e.g., 5mm, 10mm).

[0076] The thickness of the forming layer of the part (mm) is determined by the process requirements (e.g., 0.5mm, 1mm). The moving speed (mm / s) of the device relative to the substrate is set by the CNC system.

[0077] II. Intelligent Control Formula for Material Discharge

[0078] The intelligent discharge control uses the material temperature monitored in real time by a temperature sensor as the core input. By adjusting the opening degree of the rotating blade 406 in the opening and closing control device 4, it achieves "discharge when temperature meets the standard, and lockout when temperature does not meet the standard". At the same time, it matches the feeding rate with the forming requirements to ensure the forming quality of the material (clay-plastic state). The core parameter definitions of the intelligent discharge control formula are shown in Table 2.

[0079] Table 2. Definition of core parameters in the intelligent discharge control formula.

[0080] Parameter symbol Parameter name unit Definitions Real-time temperature of the material at time t ℃ The temperature is collected by temperature sensor 411 in the opening and closing control device, reflecting the actual temperature of the powder material (clay-like state) after stirring and friction. Minimum temperature for material forming ℃ The minimum temperature at which powder material transforms into a clay-like state and meets forming performance requirements (e.g., approximately 450-500℃ for aluminum alloy powder) needs to be determined through process testing. Maximum temperature of material forming ℃ The highest temperature at which the material can be prevented from overheating, oxidizing, or deteriorating (e.g., approximately 550-600℃ for aluminum alloy powder). The target opening of the rotating blade at time t ° The opening and closing angle of the rotating blade 406 in the opening and closing control device 4 is 0° for fully closed and 90° for fully open. Low temperature lock-in coefficient — when When the coefficient is 0, forced locking of material discharge is activated. High temperature adjustment coefficient — when At this time, the coefficient is 0.3-0.5. The opening is reduced to decrease the discharge rate and prevent overheated material from entering the forming zone. room temperature proportionality coefficient — when At that time, the coefficient is 0.8-1.0, and the opening degree is matched according to the feed rate. Actual feed rate at time t mm³ / s Calculated from the feed screw speed,

[0081] Formula for target opening of rotating blade (core control formula)

[0082] The discharge opening must simultaneously meet both "temperature compliance" and "feed-discharge balance," and the formula is designed in three stages:

[0083] (1) When the material temperature is lower than the minimum forming temperature ( ):

[0084]

[0085] At this point, the material has not reached the transformation temperature of the clay-plastic state, so the discharge is forcibly locked to prevent the unformed powder from flowing out and to ensure the forming quality.

[0086] (2) When the material temperature is higher than the highest forming temperature ( ):

[0087]

[0088] If the material is overheated, reduce the opening (opening ≤ 45°) and adjust it according to the ratio of "feed amount / forming requirements" to avoid overheated material accumulation or excessive supply.

[0089] (3) When the material temperature is within the acceptable range ( ):

[0090]

[0091] At this point, the material is in a qualified state. Adjust the opening (opening ≤ 90°) according to the ratio of "feed rate / forming requirements" to ensure that the feeding and discharging rates are balanced and to avoid material accumulation in the cylinder or material interruption at the discharge port.

[0092] Parameter calibration: in the formula (Powder density) (Feeding efficiency) The temperature threshold needs to be determined through preliminary testing and calibration based on the specific powder type (such as Al-6061 powder, AZ31 magnesium alloy powder) and process requirements to ensure control accuracy.

[0093] Real-time linkage: The sampling frequency of the millimeter-wave radar 102 and the temperature sensor 411 must be ≥10Hz to ensure... and Real-time performance is required; the response delay of the feeding screw drive motor 301 and the opening and closing motor 410 must be ≤0.5s to avoid deviation caused by control lag.

[0094] Boundary protection: The formula needs to be superimposed with hardware limit protection (such as the upper limit of the feed screw speed and the mechanical limit of the rotating blade opening). When the calculated value exceeds the safe range, an emergency stop is triggered to ensure the safe operation of the device.

[0095] When using the apparatus of the present invention for additive manufacturing and polishing, powdered raw materials are continuously fed into the cylinder 307 of the feeding module 3 through the feed pipe 101 of the feeding device 1; the millimeter-wave radar 102 monitors the material level in real time and intelligently controls the feeding rate; the feeding screw 304 of the feeding module 3 rotates, conveying the powder downward and initially compacting it to make it dense; the stirring friction rod 204 of the stirring friction module 2 rotates, and the knurling and semi-circular protrusion at its end rubs against the powder, causing the powder temperature to rise rapidly to a clay-like state; after the temperature sensor 411 detects that the internal temperature has reached a predetermined value, it triggers the opening and closing control device 4 to open the discharge channel; the clay-like material flows into the replaceable discharge port 5 below through the opened discharge channel under the pressure of the feeding screw 304 and is extruded through the replaceable discharge port 5, deposited on the substrate or the already formed layer, to form a new additive layer. While additive manufacturing is underway, the lifting device 6 adjusts the grinding device 7 to a suitable height, and the grinding motor 710 drives the grinding wheel 711 to rotate, performing immediate grinding on the surface of the newly formed additive layer. The position of the grinding wheel 711 can be adjusted laterally by rotating the worm gear 705 to accommodate parts of different widths. This invention achieves integrated and intelligent control of the entire process from powder feeding, friction heating, extrusion of clay-plastic materials to synchronous grinding, enabling layer-by-layer additive manufacturing and synchronous grinding of parts.

[0096] This invention achieves flexibility in material proportioning, continuity in processing, automated intelligent control, and stability in forming quality through an integrated design of coaxial powder feeding, stirring friction additive manufacturing, and grinding. This invention solves the following technical problems: 1) When traditional friction stir additive manufacturing technology uses rods and wires as raw materials, the material composition and specifications are fixed, making it difficult to flexibly adjust the proportions and achieve the forming of multi-element alloys or functionally graded materials; 2) Rod feeding relies on high-rigidity equipment to provide axial pressure, which easily leads to feeding jams when processing complex irregular structural parts, and the connection of wire materials is easily interrupted, requiring frequent shutdowns to change materials, affecting the continuity of processing; 3) In traditional friction stir additive manufacturing, the "addition" and "grinding" processes are separated, and secondary processing is required after the parts are formed, which prolongs the production cycle and easily reduces the accuracy of the parts due to positioning errors; 4) In the traditional equipment processing process, the material supply is prone to accumulation or insufficiency, and the temperature and output cannot be intelligently linked for control, resulting in a low level of automation; and 5) In traditional processing, the material has a lot of contact with the outside air, resulting in large heat loss, unstable forming temperature, and the heat generation method of friction between the stirring blade and the substrate is often used, which puts a lot of pressure on the formed structure, easily causing the formed structure to collapse and leading to a decrease in performance.

[0097] The above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and are not intended to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or improve the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in the present invention; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A coaxial powder-fed friction stir additive manufacturing and polishing apparatus, comprising: The device comprises a feeding device, a friction stirring module, a feeding module, an opening and closing control device, a replaceable discharge port, a lifting device, a polishing device and a shell, wherein: The feeding device comprises a feeding pipe connected to the feeding port of the barrel of the feeding module for feeding the powder into the barrel; The friction stirring module comprises a friction stirring rod and a friction stirring driving mechanism; The feeding module comprises a feeding screw driving mechanism, a feeding screw and a barrel, the threaded part of the feeding screw is inside the barrel, the feeding screw is driven by the feeding screw driving mechanism for feeding the powder from the feeding port to the end region of the friction stirring rod and compacting the powder; The friction stirring rod and the feeding screw are coaxially arranged and connected by bearings for relative rotation, the end of the friction stirring rod is outside the feeding screw and extends into the bottom of the barrel and further extends into the internal cavity of the opening and closing control device; The opening and closing control device is arranged below the barrel and comprises a temperature sensor and an opening and closing mechanism, the temperature sensor is used to detect the temperature in the device, when the temperature reaches a predetermined value, the opening and closing motor drives the opening and closing mechanism to open the discharge passage; The replaceable discharge port is connected below the opening and closing control device; The polishing device is fixed on the lifting device, and the lifting device is installed on the outer wall of the lower part of the shell.

2. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The feeding device further comprises a millimeter wave radar arranged in the barrel upper cover of the barrel for real-time monitoring of the remaining material height in the barrel and regulating the feeding rate.

3. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The friction stirring driving mechanism comprises a friction stirring rod transmission motor, a friction stirring rod transmission gear and a friction stirring rod gear, the friction stirring rod transmission motor drives the friction stirring rod transmission gear to rotate, which in turn drives the friction stirring rod gear to rotate, and finally drives the friction stirring rod fixed with the friction stirring rod gear to rotate.

4. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The friction stirring rod is connected with the inner ring of the bearing, and the feeding screw is connected with the outer ring of the bearing; the diameter of the end of the friction stirring rod is greater than that of the rest of the friction stirring rod, and the rod wall of the end of the friction stirring rod is provided with knurling, and the bottom end face of the end of the friction stirring rod is provided with a semicircular protrusion.

5. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The feeding screw is connected with the barrel upper cover of the barrel through the feeding screw bearing, so that the feeding screw can rotate in the barrel.

6. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The opening and closing mechanism comprises an opening and closing control mechanism upper shell, an opening and closing control mechanism lower shell, a connecting column, an intermediate pad, an opening and closing mechanism upper disc, a plurality of rotating blades, an opening and closing mechanism bottom disc, an opening and closing mechanism bottom disc gear and an opening and closing mechanism bottom disc transmission gear, the opening and closing motor drives the opening and closing mechanism bottom disc transmission gear to rotate, which in turn drives the opening and closing mechanism bottom disc gear and the opening and closing mechanism bottom disc fixed therewith to rotate, thereby driving the plurality of rotating blades to rotate along their tracks and opening the discharge passage.

7. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The replaceable discharge port is provided with bolt holes and connected with the opening and closing control device through bolts, and the replaceable discharge port can replace discharge ports of different diameters.

8. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The lifting device comprises a bottom plate, a screw drive motor, a ball screw, a guide rail slider, a guide rail and a sliding table, the bottom plate is installed on the outer wall of the lower part of the shell, the guide rail and the ball screw are fixed on the bottom plate, the ball screw is fixedly connected with the sliding table, the polishing device is installed on the sliding table, the sliding table is connected with the guide rail slider on both sides, the guide rail slider is sleeved on two parallel guide rails, and limit blocks are arranged at the two ends of the guide rail.

9. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The polishing device comprises a connecting part, a top beam, a worm rack fixing groove, a worm base, a worm, a rack, a rack sliding groove, a polishing motor and a grinding wheel, the top beam is fixed on the connecting part, the worm rack fixing groove is fixed on the top beam, the worm base and the rack sliding groove are both fixed on the worm rack fixing groove, the worm is fixed on the worm base and engaged with the rack in the rack sliding groove, and rotating the worm can drive the rack to move transversely along the rack sliding groove.

10. The coaxial powder-fed friction stir additive manufacturing and polishing apparatus of claim 1, wherein, The shell comprises a shell upper cover, a shell side, a shell lower cover, an upper clamping plate and a lower clamping plate, the shell side connects the shell upper cover and the shell lower cover, the upper clamping plate and the lower clamping plate are located between the shell upper cover and the shell lower cover and are fixed on the shell side, the shell upper cover is provided with a hole through which the feeding pipe passes, and the shell lower cover is provided with a hole through which the barrel passes.

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