Anti-blocking stirred friction powder additive device and method thereof

Abstract

This invention discloses an anti-clogging friction stir powder additive manufacturing device and method, comprising a friction shaft, a bushing, a stationary shoulder, a stirring pin, and an ion fan arranged sequentially from top to bottom. The friction shaft is designed with a variable diameter, and the variable diameter portion is externally threaded to facilitate frictional extrusion of metal powder. The powder feeding channel has a two-stage diameter reduction design, which allows the metal powder to be smoothly conveyed and dispersed into the cavity structure between the stationary shoulder and the stirring pin. Combined with the extrusion of the lower end face of the stationary shoulder and the stirring pin, the stirring friction of the stirring pin, and the axial upsetting force, the smoothness of powder conveying is ensured throughout the friction stir additive manufacturing process, thus guaranteeing the quality of the additively manufactured parts.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to metal powder additive manufacturing printing technology using friction stir technology. Specifically, it relates to an anti-clogging friction stir powder additive manufacturing device and method. Background Technology

[0002] Additive manufacturing (AM), also known as 3D printing, is a material forming and manufacturing technology that constructs solid parts by accumulating materials layer by layer based on a three-dimensional computer model. Compared with traditional manufacturing technologies, additive manufacturing has advantages such as lower processing costs, shorter cycle times, higher raw material utilization, and greater design freedom, and has been widely used in many fields such as aerospace, rail transportation, and biomedicine.

[0003] Solid-state additive manufacturing technology based on friction stirring mainly utilizes the frictional heat generated between the tool head and the workpiece material, as well as the stirring action of the tool head to induce plastic deformation of the material, thereby thermoplasticizing the metal material to be added. Under the stirring and upsetting action of the tool head, the material is combined with the substrate or the already added layer, and finally, the thermoplasticized material is accumulated layer by layer to form a structural component. Summary of the Invention

[0004] The present invention aims to provide a powder additive manufacturing device and method for preventing material blockage and friction stirring, which can form powder on the surface of a workpiece to form a dense, low-defect printed part.

[0005] The present invention adopts the following technical solution:

[0006] A friction powder additive manufacturing device for preventing material blockage includes a friction shaft 1, a bushing 2, a stationary shoulder 3, a stirring needle 4, and an ion fan 8 arranged sequentially from top to bottom.

[0007] The friction shaft 1 includes a fixed shaft portion 10 with a columnar structure and a variable shaft portion 20 with a frustum-shaped structure. The variable shaft portion 20 continuously narrows from top to bottom and has a thread 30 on its exterior. A bushing 2 is fitted onto the outside of the friction shaft 1 and is coaxial with the friction shaft 1, maintaining a certain gap. The gap between the friction shaft 1 and the bushing 2 forms a powder feeding channel 5 for the flow of metal powder. The powder feeding channel 5 includes a first annular channel 40 and a second conical annular channel 50 with a continuously narrowing diameter. The stationary shoulder 3 has an axial through hole and is fixed to the outside of the bottom end of the bushing 2. The working end face of the stationary shoulder has a forming opening, which is a notched structure located on the stationary shoulder; the stirring needle 4 is frustum-shaped, and there is a cavity structure between the stirring needle 4 and the stationary shoulder 3, which is connected to the powder feeding channel and the forming opening respectively; the vent 6 is located on the outer wall of the first powder feeding channel 40 and is connected to the air supply pipe 13 of the ion blower 8; an exhaust port 14 is opened on the outer wall of the second powder feeding channel 50. The vent 6 is used to receive the ionized air in the ion blower, eliminate the electrostatic interaction between the flowing metal powders in the additive manufacturing device, and make them flow more smoothly.

[0008] The anti-clogging material stirring friction powder additive device has a first channel 40 with an inner diameter slightly larger than the second channel 50, and the bottom of the first channel 40 is chamfered to make the powder flow more easily.

[0009] The aforementioned anti-clogging material stirring friction powder additive device, wherein the friction shaft 1 is made of tool steel or ceramic, which has high hardness and is easy to rub against metal powder.

[0010] The anti-clogging material stirring friction powder additive device includes an ion fan 8 comprising an air inlet 9, a protective net, a drive rod 11, a fan blade 12, and an air supply pipe 13.

[0011] The aforementioned anti-clogging material stirring friction powder additive manufacturing device has a groove structure with a width of 4-32mm in the horizontal direction and a depth of 1-8mm; the groove structure is inclined downward from the inside out, wherein the inclination angle is 1-3°.

[0012] The anti-clogging material stirring friction powder additive manufacturing device has a cavity structure with an indentation of 1-8mm relative to the working end face of the stationary shoulder, and the indentation is greater than or equal to the depth of the forming opening; the outlet of the powder feeding channel is located entirely on the side wall of the cavity structure, and the cavity structure is an annular cavity or a circular cavity.

[0013] The aforementioned anti-clogging material stirring friction powder additive device has an air inlet 9 at one end of the ion blower 8, a protective net is installed at the air inlet 9, a drive rod 11 is installed inside the ion blower 8, a set of fan blades 12 are installed on the outside of the drive rod 11, and an air supply pipe 13 is connected to the other end of the ion blower 8, and the other end of the air supply pipe 13 is connected to the vent 6 outside the bushing 2.

[0014] The aforementioned anti-clogging material stirring friction powder additive device has a mesh cover installed on the exhaust port 14 to prevent the internal metal powder from being blown out by air circulation when the friction shaft rotates.

[0015] The additive manufacturing method according to any of the anti-clogging material stirring friction powder additive apparatuses includes the following steps:

[0016] S1, the metal powder is conveyed from the powder feeder to the powder feeding channel inlet through the powder feeding pipe, and then squeezed downward into the first powder feeding channel under its own gravity and the rotation of the friction shaft.

[0017] S2. Connect the air supply pipe of the ion blower to the vent hole of the bushing. The ion blower uses a DC high-voltage generator to increase the input voltage and output positive and negative voltages respectively. A strong electric field is generated between the positive and negative electrodes, causing the molecules in the air to be ionized. Turn on the ion blower, and the ionized air is transported to the powder feeding channel through the air supply pipe to eliminate the static electricity in the metal powder and make its flow smoother.

[0018] S3, then the metal powder enters the second channel, which is a conical channel with a continuously narrowing diameter along the vertical direction. At this time, the friction shaft is designed with a narrowing diameter and has threads on the outside of the friction shaft to increase the friction between the friction shaft and the metal powder, and to compact the metal powder again.

[0019] S4, when the metal powder enters the cavity structure between the stationary shoulder and the stirring pin, it undergoes plastic deformation under the stirring friction of the stirring pin. Thus, under the extrusion of the shoulder, the stirring friction of the stirring pin, and the axial forging force, the plasticized material melts and deposits into an additive layer through the forming port in the additive direction. When the additive layer begins to form, the stirring pin and the stationary shoulder are controlled to move forward along the additive direction to form a dense additive layer on the substrate.

[0020] S5. After completing one additive layer, the additive device is moved to the next additive layer and powder is fed repeatedly and pushed downwards and frictionally extruded to obtain multiple additive layers.

[0021] In the additive manufacturing method described above, the friction shaft rotates at a speed of 1500-4000 rpm, the pressure is 0-0.5 mm, and the tilt angle is 0-2°; the stirring needle rotates at a speed of 300-1500 mm / min.

[0022] The beneficial effects of this invention compared to the prior art are as follows:

[0023] The friction shaft is designed with a variable diameter, and the variable diameter part is threaded on the outside to facilitate the friction extrusion of metal powder. The powder feeding channel has a two-stage diameter reduction design, which allows the metal powder to be smoothly transported and dispersed into the cavity structure between the stationary shaft shoulder and the stirring pin. Combined with the extrusion between the lower end face of the stationary shaft shoulder and the stirring pin, the stirring friction of the stirring pin, and the axial upsetting force, the smoothness of powder transport is ensured throughout the friction stir additive manufacturing process, thus ensuring the quality of the additively manufactured parts.

[0024] When the metal powder flows through the powder feeding channel, the ion fan is turned on. The generated circulating ion airflow and friction shaft repeatedly homogenize and disperse the metal powder, which can effectively neutralize the static electricity on the surface of the metal powder, reduce the adhesion between powders, disperse the agglomerated powder, and effectively improve the powder flowability. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural schematic diagram of the additive manufacturing device of the present invention;

[0026] Figure 2 This is a partial cross-sectional view of the additive manufacturing device of the present invention;

[0027] Figure 3 This is a schematic diagram of the three-dimensional structure of the ion fan used in this invention;

[0028] Figure 4 This is a schematic diagram of a partial cross-sectional structure of the ion fan in this invention.

[0029] Combination Figure 1-4 As shown, according to an exemplary embodiment of the present invention, the system includes a friction shaft 1, a bushing 2, a stationary shoulder 3, and a stirring needle 4 arranged sequentially from top to bottom. The friction shaft 1 consists of a fixed shaft portion 10, a variable shaft portion 20, and a thread 30. A powder feeding channel 5 is formed between the friction shaft 1 and the bushing 2, which is divided into a first channel 40 and a second channel 50. A vent hole 6 is provided on the bushing 2. A cavity structure 7 exists between the stationary shoulder 3 and the stirring needle 4. An ion fan 8 includes an air inlet 9, a drive rod 11, fan blades 12, an air supply pipe 13, and an exhaust port 14. Detailed Implementation

[0030] 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. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Example 1

[0031] Combination Figure 1-4 As shown, the present invention provides a metal powder additive manufacturing device, including a friction shaft 1, a bushing 2, a stationary shoulder 3, and a stirring needle 4 arranged sequentially from top to bottom, as well as an ion fan 8 for solving the problem of metal powder clogging and difficulty in feeding. The ion fan 8 includes an air inlet 9, a protective net, a drive rod 11, a fan blade 12, and an air supply pipe 13.

[0032] The friction shaft 1 includes a fixed shaft portion 10 with a columnar structure and a variable shaft portion 20 with a frustum-shaped structure. The variable shaft portion 20 continuously narrows from top to bottom and has threads 30 on its exterior to increase the friction force on the metal powder and compress it. The friction shaft 1 is made of tool steel or ceramic, which has high hardness and is easy to rub against the metal powder. The bushing 2 is fitted on the outside of the friction shaft 1 and is coaxial with the friction shaft 1, maintaining a certain gap. The gap between the friction shaft 1 and the bushing 2 forms a powder feeding channel 5 for the flow of metal powder. The powder feeding channel 5 includes a first annular channel 40 and a second conical annular channel 50. The inner diameter of the first channel 40 is slightly larger than that of the second channel 50. The bottom of the first channel 40 is chamfered to facilitate powder flow.

[0033] The stationary shoulder 3 has an axial through hole and is fixed to the outside of the bottom end of the bushing 2. The working end face of the stationary shoulder has a forming opening, which is a notch structure located on the stationary shoulder. The notch structure has a width of 4-32mm in the horizontal direction and a depth of 1-8mm. The notch structure is inclined downward from the inside to the outside, wherein the inclination angle is 1-3°.

[0034] The stirring pin 4 is frustum-shaped, and a cavity structure exists between the stirring pin 4 and the stationary shoulder 3. The cavity structure is connected to both the powder feeding channel and the forming port. The indentation of the cavity structure relative to the working end face of the stationary shoulder is 1-8 mm, and the indentation is greater than or equal to the depth of the forming port. The outlet of the powder feeding channel is located entirely on the side wall of the cavity structure, which is either an annular or circular cavity.

[0035] One end of the ion fan 8 is provided with an air inlet 9, and a protective net is installed at the air inlet 9 to protect the fan blades 12 from external factors. The ion fan 8 is equipped with a drive rod 11, and a set of fan blades 12 are installed on the outside of the drive rod 11. The other end of the ion fan 8 is connected to an air supply pipe 13, and the other end of the air supply pipe 13 is connected to the ventilation hole 6 outside the bushing 2.

[0036] Vent 6 is located on the outer wall of the first powder feeding channel 40 and is connected to the air supply pipe 13 of the ion blower 8. Vent 6 is used to receive ionized air from the ion blower, eliminating the electrostatic interaction between the flowing metal powders in the additive manufacturing device, allowing them to flow more smoothly. An exhaust port 14 is opened on the outer wall of the second powder feeding channel 50 to promote gas circulation within the additive manufacturing device. A mesh cover is installed on the exhaust port 14 to prevent the air circulation from blowing out the internal metal powder when the friction shaft rotates. When the metal powder flows into the cavity structure 7 between the stationary shoulder 3 and the stirring needle 4, it undergoes plastic deformation under the stirring friction of the stirring head 4. Thus, under the extrusion of the shoulder 3, the stirring friction of the stirring needle 4, and the axial forging force, the plasticized material melts and deposits into an additive layer in the additive direction through the forming port. When the additive layer begins to form, the stirring head and the stationary shoulder are controlled to advance along the additive direction, forming a dense additive layer on the substrate. Example 2

[0037] This embodiment provides a method for additive manufacturing of metal powder by stirring, which includes solid-phase additive manufacturing on a substrate using the additive manufacturing apparatus provided in Embodiment 1, with aluminum alloy as the substrate and aluminum alloy powder as the additive material, to achieve an additive manufacturing effect of more than 3 layers.

[0038] Specifically, the triboelectric additive manufacturing method provided in this embodiment includes the following steps:

[0039] Step 1: Fix the aluminum alloy substrate to the worktable, move the friction additive manufacturing device to a position 3mm above the substrate and set it at a 3° angle.

[0040] Step 2: At the start-up, the stirring needle 4, while rotating, penetrates the additively manufactured aluminum alloy substrate until the lower end face of the stationary shoulder 3 contacts the upper surface of the additively manufactured substrate, and the substrate is preheated.

[0041] Step 3: Start the powder feeding mechanism to send aluminum alloy powder into the powder feeding channel. At the same time, start the ion fan 8 to eliminate the static electricity between the metal powder passing through the powder feeding channel. Drive the friction shaft 1 and the drive rod 11 of the ion fan 8 to make the metal powder flow downward into the cavity structure 7 between the stationary shaft shoulder 3 and the stirring needle 4, and come into contact with the rotating stirring needle 4. The powder undergoes plastic deformation under the friction and stirring action of the stirring needle 4.

[0042] Step 4: Under the pressure of the shoulder 3, the stirring friction of the stirring pin 4, and the axial forging force, the plasticized material melts and deposits into an additive layer in the additive direction through the forming orifice. When the additive layer begins to form, the stirring head and the stationary shoulder are controlled to move forward in the additive direction to form a dense additive layer on the substrate.

[0043] Step 5: After completing one layer of additive manufacturing, move the friction additive manufacturing device to a position 3mm above the previous layer and repeat steps 2 to 4 to obtain multiple layers of additive manufacturing.

[0044] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A clog-resistant friction-stir powder additive manufacturing device, comprising: The assembly includes, from top to bottom, a friction shaft (1), a bushing (2), a stationary shoulder (3), a stirring needle (4), and an ion fan (8); the friction shaft (1) includes a fixed shaft portion (10) with a columnar structure and a variable shaft portion (20) with a frustum-shaped structure, the variable shaft portion (20) continuously narrowing from top to bottom, and the variable shaft portion (20) is provided with a thread (30) on the outside; the bushing (2) is sleeved on the outside of the friction shaft (1) and is coaxial with the friction shaft (1) and maintains a certain gap, the gap between the friction shaft (1) and the bushing (2) forms a powder feeding channel (5) for the flow of metal powder; the powder feeding channel (5) includes a first annular channel (40) and a second conical annular channel (50) with a continuously narrowing diameter; the stationary shoulder (3) has an axial through hole and is fixed outside the bottom end of the bushing (2), the working end face of the stationary shoulder has a forming opening, the forming opening being a notched structure located on the stationary shoulder; The stirring needle (4) is frustum-shaped, and there is a cavity structure between the stirring needle (4) and the stationary shoulder (3). The cavity structure is connected to the powder feeding channel and the forming port respectively. The vent (6) is located on the outer wall of the first powder feeding channel (40) and is connected to the air supply pipe (13) of the ion blower (8). An exhaust port (14) is opened on the outer wall of the second powder feeding channel (50). The vent (6) is used to receive the ionized air in the ion blower, eliminate the electrostatic effect between the metal powder flowing in the additive manufacturing device, and make it flow more smoothly. The inner diameter of the first channel (40) is slightly larger than that of the second channel (50). The bottom of the first channel (40) is chamfered so that the powder can flow more easily. The concavity of the cavity structure relative to the working end face of the stationary shoulder is 1-8mm, and the concavity is greater than or equal to the depth of the forming port. The outlet of the powder feeding channel is located on the side wall of the cavity structure. The cavity structure is an annular cavity.

2. The anti-jamming friction stir powder additive manufacturing device of claim 1, wherein, The friction shaft (1) is made of tool steel or ceramic.

3. The anti-clogging material stirring friction powder additive manufacturing device according to claim 1, characterized in that, The ion fan (8) includes an air inlet (9), a protective net, a drive rod (11), fan blades (12), and an air supply pipe (13).

4. The anti-clogging material stirring friction powder additive manufacturing device according to claim 1, characterized in that, The notched structure has a width of 4-32mm in the horizontal direction and a depth of 1-8mm; the notched structure is inclined downward from the inside out, wherein the inclination angle is 1-3°.

5. The anti-clogging material stirring friction powder additive manufacturing device according to claim 1, characterized in that, One end of the ion fan (8) is provided with an air inlet (9), and a protective net is installed at the air inlet (9). The ion fan (8) is equipped with a drive rod (11), and a set of fan blades (12) is installed on the outside of the drive rod (11). The other end of the ion fan (8) is connected to an air supply pipe (13), and the other end of the air supply pipe (13) is connected to the ventilation hole (6) outside the bushing (2).

6. The anti-clogging material stirring friction powder additive manufacturing device according to claim 1, characterized in that, A mesh cover is installed on the exhaust port (14) to prevent the internal metal powder from being blown out by the air circulation when the friction shaft rotates.

7. The additive manufacturing method of the anti-clogging material stirring friction powder additive manufacturing device according to any one of claims 1-6, comprising the following steps: S1, the metal powder is conveyed from the powder feeder to the powder feeding channel inlet through the powder feeding pipe, and then squeezed downward into the first powder feeding channel under its own gravity and the rotation of the friction shaft. S2, connect the air supply pipe of the ion blower to the vent hole of the bushing. The ion blower uses a DC high voltage generator to increase the input voltage and output positive and negative voltages respectively. A strong electric field is generated between the positive and negative electrodes, which ionizes the molecules in the air. Turn on the ion blower and transport the ionized air through the air supply pipe to the powder feeding channel to eliminate the static electricity in the metal powder and make it flow more smoothly. S3, then the metal powder enters the second channel, which is a conical channel with a continuously narrowing diameter along the vertical direction. At this time, the friction shaft is designed with a narrowing diameter and has threads on the outside of the friction shaft to increase the friction between the friction shaft and the metal powder, and to compact the metal powder again. S4, when the metal powder enters the cavity structure between the stationary shoulder and the stirring pin, it undergoes plastic deformation under the stirring friction of the stirring pin. Thus, under the extrusion of the shoulder, the stirring friction of the stirring pin, and the axial forging force, the plasticized material melts and deposits into an additive layer through the forming port in the additive direction. When the additive layer begins to form, the stirring pin and the stationary shoulder are controlled to move forward along the additive direction to form a dense additive layer on the substrate. S5. After completing one additive layer, the additive device is moved to the next additive layer and powder is fed repeatedly and pushed downwards and frictionally extruded to obtain multiple additive layers.

8. The additive manufacturing method according to claim 7, characterized in that, The friction shaft has a rotational speed of 1500-4000 rpm, a downward pressure of 0-0.5 mm, and an inclination angle of 0-2°; the stirring needle has a rotational speed of 300-1500 mm / min.

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