Device for improving stability of continuous spiral feeding solid additive

Abstract

The utility model discloses a device for improving the stability of a continuous spiral feeding solid additive, which comprises a main shaft, a fixed plate, a spiral feeding rod and an inner runner shaft shoulder, the inner runner shaft shoulder is sleeved on the spiral feeding rod, the spiral feeding rod is connected with the main shaft, and the main shaft and the inner runner shaft shoulder are respectively arranged on two sides of the fixed plate; a spiral feeding groove is formed in the periphery of the spiral feeding rod, a feeding guide pipe is arranged in the inner flow channel shaft shoulder, and a liquid cooling channel is formed in the inner flow channel shaft shoulder. The liquid cooling channel is arranged in the inner flow channel shaft shoulder, the inner wall of the inner flow channel shaft shoulder is cooled, materials on the upper half portion in the spiral feeding groove are kept in a non-plasticized state, shearing force and friction force are improved, and therefore enough component force for pushing materials downwards is generated, and material pushing efficiency is improved. The stability of the material in the spiral wire / powder feeding solid material adding process is improved, and the problems that in the long-time material adding process, due to the fact that the temperature is too high, the particle-state material is plasticized too early, friction force is reduced, discharging is unsmooth, and a wire inlet is blocked are solved.

Description

Technical Field

[0001] This utility model relates to the field of solid additive manufacturing technology, specifically to a device for improving the stability of continuous spiral feeding solid additive manufacturing. Background Technology

[0002] Friction stir additive manufacturing (FSAM) is a novel solid-state additive manufacturing technology that solves the problem that current metal additive manufacturing (3D printing) methods mostly rely on welding, which uses lasers, electric arcs, or electron beams as heat sources to raise the working temperature above the material's melting point. This melting of the base material leads to defects such as porosity and cracks during solidification, reducing the performance of 3D printed parts. FSAM utilizes the frictional heat generated by the shoulders and stirring pins between the workpiece and the material to plasticize and flow the material, forming a weld. The weld metal does not melt, is free of porosity and cracks, exhibits minimal deformation, and refines the grain size, significantly improving the mechanical properties of additively manufactured parts and enhancing the structural utilization of manufactured components. It is considered a major breakthrough in the field of metal additive manufacturing.

[0003] Currently, FSAM (Fixed Solid Additive Manufacturing) feed modes include sheet metal, rods, filaments, powders, and granules. FSAM using filaments / powders offers high raw material precision, high feeding efficiency and continuity, and high additive strength. In the spiral feeding filament / powder solid additive manufacturing process, a shoulder connects to the die head and remains stationary relative to it. The feeding screw, connected to the rotating spindle, rotates relative to the shoulder. The filament enters through the filament inlet on the shoulder and is inserted into the spiral groove of the rotating feeding screw via the fixed shoulder. The filament cannot move except along the direction of the inlet; after insertion, it is cut into granules by the rotating feeding screw and moves downwards with the spiral groove. Therefore, regardless of whether it is filament or powder, it exists in a granular state within the feeding screw. When the feeding screw rotates at high speed, it generates heat through friction with the substrate. The granular material, heated, gradually becomes plastic in the lower part of the spiral groove and, as the die head moves, is coated onto the substrate to form the additive. To achieve smooth discharge during this process, a tool or material needs to provide a certain force to push the plasticized material within the tool along the spiral groove. However, when filament / powder is used as feed material, it exists in granular form within the spiral groove and cannot directly provide the force to push the plastic material out of the tool outlet. It primarily relies on the frictional force between the feed screw and the inner wall of the shoulder. During prolonged additive manufacturing, the temperature inside the shoulder rises, significantly altering the material's state and reducing the downward force generated by friction. This prevents the plasticized metal from smoothly exiting the outlet, leading to blockage. Furthermore, during extended additive manufacturing, the filament inlet temperature becomes excessively high, causing the filament to expand upon entry and adhere to the inlet, hindering continuous feeding. Therefore, solid additive manufacturing using filament / powder feed is unsuitable for long-term continuous additive manufacturing. Summary of the Invention

[0004] The technical problem this invention aims to solve is to provide a device for improving the stability of continuous spiral feeding solid additive manufacturing. A liquid cooling channel is installed within the inner flow channel shoulder. The low-temperature coolant within the liquid cooling channel cools the inner wall of the inner flow channel shoulder, thereby cooling the material within the spiral feeding trough. This keeps the material in the upper part of the spiral feeding trough in a solid granular state, providing sufficient downward friction for the additive manufacturing process, ensuring smooth material ejection and avoiding problems such as poor material discharge or even blockage of the filament inlet caused by premature plasticization of the granular material. By machining the liquid cooling channel inside the inner flow channel shoulder body, external water cooling jackets and cooling spiral tubes are eliminated, significantly reducing the device size and meeting the requirements for lightweight design. Simultaneously, the internal liquid cooling channel provides superior cooling to the inner wall of the shoulder.

[0005] To solve the above-mentioned technical problems, this utility model provides a device for improving the stability of continuous spiral feeding solid additive manufacturing, including a main shaft, a fixed plate, a spiral feeding rod and an inner flow channel shoulder. The inner flow channel shoulder is sleeved on the spiral feeding rod, and the spiral feeding rod is connected to the output end of the main shaft. The main shaft and the inner flow channel shoulder are respectively installed on both sides of the fixed plate.

[0006] The spiral feeder is provided with a spiral feed groove on the outer periphery of the spiral feeder rod, and a feed guide is provided in the inner flow channel shoulder. The feed guide is used to supply material to the spiral feed groove.

[0007] A liquid cooling channel is also provided inside the inner flow channel shoulder, and the spiral feed rod passes through the liquid cooling channel without contacting it.

[0008] In the feeding process of friction stirring additive manufacturing, the main shaft drives the spiral feed rod to rotate synchronously. The inner flow channel shoulder, the fixed plate and the outer head are relatively stationary. The inner flow channel shoulder and the spiral feed rod rotate relative to each other. The material entering through the feeding guide is cut into particles by the spiral feeding groove. The granular material moves downward with the spiral feeding groove under the action of friction and is discharged.

[0009] A liquid cooling channel is set in the inner flow channel shoulder. The low temperature coolant in the liquid cooling channel cools the inner wall of the inner flow channel shoulder, so that the material in the upper part of the spiral feed trough is kept in a non-plasticized state. This increases the shear force and friction, thereby generating more downward pushing force. This improves the stability of the material during the spiral feeding of filaments / powder in solid additive manufacturing and avoids the problem of premature plasticization of too many particles due to excessive temperature during long-term additive manufacturing, which reduces friction and causes poor material discharge and blockage of the filament inlet.

[0010] The liquid cooling channel is located inside the inner flow channel shoulder body, which provides better cooling effect and avoids the need for additional external water cooling jackets, cooling spiral tubes and other devices, greatly reducing the size of the device and meeting the requirements of lightweight design.

[0011] Furthermore, the liquid cooling channel is a spiral structure or a zigzag structure arranged around the spiral feed rod.

[0012] Furthermore, the distance between the inner side of the liquid cooling channel and the inner wall of the inner flow channel shoulder is 2±0.5mm.

[0013] Furthermore, the inlet and outlet of the liquid cooling channel are respectively connected to the coolant outlet and coolant inlet of the cooling mechanism, and the liquid cooling channel and the cooling mechanism form a circulation loop.

[0014] Furthermore, the feed end of the feed conduit is connected to the feed mechanism.

[0015] Furthermore, the inner diameter of the feeding conduit is 0.5-2 mm smaller than the width of the spiral feeding trough.

[0016] Furthermore, the upper part of the spiral feed rod is a conical structure and the lower part is a cylindrical structure, and the spiral feed groove is disposed on the cylindrical structure part.

[0017] Furthermore, the gap width between the spiral feed rod of the cylindrical structure and the inner wall of the inner flow channel shoulder is 0.02-0.5mm.

[0018] Furthermore, a shoulder is provided at the bottom end of the spiral feed rod, and one or more protrusions are provided on the bottom surface of the shoulder. When there are multiple protrusions, all the protrusions may have the same or different heights.

[0019] Furthermore, the structure of each of the aforementioned protrusions is individually selected from cubes, cuboids, hemispheres, cones, ellipsoids, cylinders, tetrahedrons, teardrop shapes, or impeller shapes.

[0020] The beneficial effects of this utility model are:

[0021] This invention relates to a device for improving the stability of continuous spiral feeding solid additive manufacturing. By setting a liquid cooling channel in the inner flow channel shoulder, the inner wall of the inner flow channel shoulder is cooled, keeping the material in the upper part of the spiral feeding groove in a non-plasticized state. This increases the shear force and friction, thereby generating a sufficient downward pushing force. This improves the stability of the material during spiral feeding of filaments / powder in solid additive manufacturing and avoids the problem of premature plasticization of granular material due to excessively high temperature during long-term additive manufacturing, which reduces friction and causes poor material discharge and blockage of the filament inlet.

[0022] This invention features a liquid cooling channel machined inside the inner flow channel shoulder body, eliminating the need for external water cooling jackets, cooling spiral tubes, and other devices. This significantly reduces the size of the device, meeting the requirements for lightweight design. At the same time, the internal liquid cooling channel provides superior cooling for the inner wall of the shoulder. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the additive manufacturing process of the device for improving the stability of solid additive manufacturing by continuous spiral feeding according to this utility model.

[0024] Figure 2 This is a schematic diagram of the spiral feed rod structure of this utility model;

[0025] Figure 3 This is a schematic diagram of the spiral liquid cooling channel structure of this utility model;

[0026] Figure 4 This is a schematic diagram of the liquid cooling channel structure of the folding-back structure of this utility model;

[0027] The following are the labels in the diagram: 1. Main shaft, 2. Fixed plate, 3. Spiral feed rod, 31. Spiral feed trough, 32. Shoulder, 4. Inner flow channel shoulder, 41. Feeding conduit, 42. Liquid cooling channel, 421. Liquid inlet, 422. Liquid outlet, 5. Base plate, 6. Material adding, 7. Cooling mechanism, 8. Feeding mechanism. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention.

[0029] This embodiment provides a device for improving the stability of solid additive manufacturing using continuous spiral feeding. A schematic diagram of the additive manufacturing process is shown below. Figure 1 As shown, the device includes a main shaft 1, a fixed plate 2, a spiral feed rod 3, and an inner flow channel shoulder 4. The inner flow channel shoulder 4 is sleeved on the spiral feed rod 3, and the spiral feed rod 3 is connected to the output end of the main shaft 1. The main shaft 1 and the inner flow channel shoulder 4 are respectively installed on both sides of the fixed plate 2. A spiral feed groove 31 is provided on the outer periphery of the spiral feed rod 3, such as... Figure 2 As shown, a feeding conduit 41 is provided inside the inner flow channel shoulder 4, which is used to supply material to the spiral feeding trough 31; a liquid cooling channel 42 is also provided inside the inner flow channel shoulder 4, such as... Figure 3-4 As shown, the spiral feed rod 3 passes through the liquid cooling channel 42 and is disposed without contact between the two.

[0030] In this embodiment, during the feeding of friction stir additive manufacturing, the main shaft 1 drives the spiral feed rod 3 to rotate synchronously. The inner flow channel shoulder 4, the fixed plate 2, and the outer die head are relatively stationary, while the inner flow channel shoulder 4 and the spiral feed rod 3 rotate relative to each other. The filamentous material entering through the feeding guide 41 is cut into particles by the spiral feed groove 31. Under the action of friction, the granular material moves downward with the spiral feed groove 31 and is discharged. The die head drives the entire device to move and places the spiral feed rod 3 above the substrate 5, continuously adding material layer by layer on the substrate 5 to obtain the additive body 6.

[0031] A liquid cooling channel 42 is provided in the inner flow channel shoulder 4. The low-temperature coolant (1-5℃) in the liquid cooling channel 42 cools the inner wall of the inner flow channel shoulder 4, keeping the material in the upper part of the spiral feed trough 31 in a non-plasticized state. This increases the shear force and friction, thereby generating more downward pushing force and improving the stability of the material during the spiral feeding / powder solid additive manufacturing process. It also avoids the problem of premature plasticization of the granular material due to excessive temperature during long-term additive manufacturing, which reduces friction and causes poor material discharge and blockage of the filament inlet. The liquid cooling channel 42 is located inside the inner flow channel shoulder 4 body, resulting in better cooling effect. At the same time, it avoids the need for additional external water cooling jackets, cooling spiral tubes, and other devices, greatly reducing the size of the device and meeting the requirements of lightweight design.

[0032] Specifically, the liquid cooling channel 42 is a spiral structure or a zigzag structure arranged around the spiral feed rod 3, such as... Figure 3-4 As shown; the distance between the inner side of the liquid cooling channel 42 and the inner wall of the inner flow channel shoulder 4 is 2±0.5mm.

[0033] Specifically, the inlet 421 and outlet 422 of the liquid cooling channel 42 are respectively connected to the coolant outlet and coolant inlet of the cooling mechanism 7. The liquid cooling channel 42 and the cooling mechanism 7 form a circulation loop. The feed end of the feeding conduit 41 is connected to the feeding mechanism 8.

[0034] Specifically, the additive manufacturing material introduced by the feeding conduit 41 is either filament or powder. The diameter of the filament ranges from 0.2 to 7 mm, and the particle size of the powder ranges from 0.05 to 1 mm. When feeding filament, the diameter of the feeding conduit 41 is 0.1 to 0.3 mm larger than the diameter of the filament. The inner diameter of the feeding conduit 41 is 0.5 to 2 mm smaller than the width of the spiral feeding groove 31. When the difference between the groove width and the diameter of the feeding conduit 41 is less than 0.5 mm, the material is difficult to enter the spiral feeding groove 31 during rotation. When the difference between the groove width and the diameter of the feeding conduit 41 is greater than 2 mm, it affects the cutting effect of the spiral feeding groove 31 on the filament. The spindle 1 rotates at a speed of 100-2500 r / min, the additive manufacturing speed is 50-2000 mm / min, the feeding speed is 0.5-10 m / min, and the single-layer additive manufacturing thickness is 0.05-5 mm.

[0035] Specifically, the upper part of the spiral feed rod 3 is conical and the lower part is cylindrical, and the spiral feed groove 31 is located in the cylindrical part. The connection surface between the cylindrical and conical structures is defined as the h-plane. The discharge end of the feeding conduit 41 is at least 3mm below the h-plane and at least 5mm above the discharge end of the spiral feed rod 3. When the discharge end of the feeding conduit 41 is less than 3mm below the h-plane, material tends to accumulate at the top of the spiral feed groove 31, causing material blockage at the inlet. When the discharge end of the feeding conduit 41 is less than 5mm above the discharge end of the spiral feed rod 3, the inlet temperature is affected by the spiral feed... The feed rod 3 and the inner flow channel shoulder 4 generate significant heat, which can easily cause overheating and material to stick to the wire inlet. The gap width between the spiral feed rod 3 and the inner wall of the inner flow channel shoulder 4 in the cylindrical structure is 0.02-0.5mm. If the gap is too small, the torque of the main shaft 1 will be high during high-speed rotation, which can easily cause the main shaft 1 to seize up and stop rotating. If the gap is too large, too much material will enter the gap and form a material layer wrapped around the spiral feed rod 3, which reduces the friction between the material and the inner flow channel shoulder 4 and causes material blockage.

[0036] Specifically, the bottom end of the spiral feed rod 3 is provided with a shoulder 32, the diameter of which is 10-40mm. If the diameter of the shoulder 32 is too small, the rigidity of the spiral feed rod 3 will be low, affecting its service life. The surface features provide agitation for the deposited filler material or workpiece surface. The bottom surface of the shoulder 32 is provided with one or more protrusions (not shown in the figure). When there are multiple protrusions, all the protrusions may have the same or different heights. The structure of each protrusion is uniquely selected from cubes, cuboids, hemispheres, cones, ellipsoids, cylinders, tetrahedrons, teardrop shapes, or impeller shapes. The protrusions can effectively improve the flowability of the additive material. During the agitation of the additive material, they drive the material in the spiral feed trough 31 to be discharged for additive processing, ensuring the smoothness of the material output during the additive process.

[0037] In summary, this invention improves the stability of continuous spiral feeding solid additive manufacturing by setting a liquid cooling channel within the inner flow channel shoulder. This cools the inner wall of the inner flow channel shoulder, keeping the material in the upper part of the spiral feeding groove in a non-plasticized state. This increases shear force and friction, generating sufficient downward pushing force and improving material stability during spiral feeding / powder solid additive manufacturing. It avoids problems such as premature plasticization of the granular material due to excessively high temperatures during prolonged additive manufacturing, which reduces friction and causes poor discharge and blockage of the filament inlet. The liquid cooling channel is machined inside the inner flow channel shoulder body, eliminating the need for external water cooling jackets, cooling spiral tubes, etc., significantly reducing the device size and meeting lightweight requirements. Simultaneously, the internal liquid cooling channel provides superior cooling to the inner wall of the shoulder.

[0038] The above-described embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

Claims

1. A device for improving the stability of continuous screw feed solid additive manufacturing, characterized in that, It includes a main shaft, a fixed plate, a spiral feed rod, and an inner flow channel shoulder. The inner flow channel shoulder is sleeved on the spiral feed rod, and the spiral feed rod is connected to the output end of the main shaft. The main shaft and the inner flow channel shoulder are respectively installed on both sides of the fixed plate. The spiral feeder is provided with a spiral feed groove on the outer periphery of the spiral feeder rod, and a feed guide is provided in the inner flow channel shoulder. The feed guide is used to supply material to the spiral feed groove. A liquid cooling channel is also provided inside the inner flow channel shoulder, and the spiral feed rod passes through the liquid cooling channel without contacting it.

2. The apparatus for improving the stability of continuous screw feed solid additive manufacturing as described in claim 1, characterized in that, The liquid cooling channel is a spiral structure or a folding structure arranged around the spiral feed rod.

3. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 2, characterized in that, The distance between the inner side of the liquid cooling channel and the inner wall of the inner flow channel shoulder is 2±0.5mm.

4. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 1, characterized in that, The liquid cooling channel's inlet and outlet are connected to the coolant outlet and coolant inlet of the cooling mechanism, respectively, forming a circulation loop with the cooling mechanism.

5. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 1, characterized in that, The feed inlet end of the feed conduit is connected to the feed mechanism.

6. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 1, characterized in that, The inner diameter of the feeding conduit is 0.5-2 mm smaller than the width of the spiral feeding trough.

7. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 1, characterized in that, The upper part of the spiral feed rod is conical and the lower part is cylindrical, and the spiral feed groove is located on the cylindrical part.

8. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 7, characterized in that, The gap width between the spiral feed rod of the cylindrical structure and the inner wall of the inner flow channel shoulder is 0.02-0.5mm.

9. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 1, characterized in that, The bottom end of the spiral feed rod is provided with a shoulder, and the bottom surface of the shoulder is provided with one or more protrusions. When there are multiple protrusions, all the protrusions may have the same or different heights.

10. The apparatus for improving the stability of continuous spiral feeding solid additive manufacturing as described in claim 9, characterized in that, Each of the aforementioned protrusions has a unique structure selected from cubes, cuboids, hemispheres, cones, ellipsoids, cylinders, tetrahedrons, teardrop shapes, or impeller shapes.

Images