Counter-rotating frictional frictional additive manufacturing device and method

Abstract

The application discloses a kind of counter-rotating friction type friction stir additive manufacturing device and method, including friction preheating shoulder, counter-rotating wire hot plasticizing system, water-cooling top forging block and substrate;The counter-rotating wire hot plasticizing system includes a pair of coaxial high-speed rotatable disc, disc rotating direction is reverse each other, wire is clamped in two discs and hot plasticizing due to rotating friction;When processing, friction preheating shoulder is rotated and moved in substrate or already additive surface, and heats and plasticizes substrate or additive layer;Counter-rotating wire hot plasticizing system rotates and plasticizes wire, so that plasticized metal fills the gap between two discs and then flows out from below, and is deposited on the substrate or already additive layer processed by friction preheating shoulder key.This application provides the counter-rotating friction type small-size friction stir additive manufacturing device can realize the friction stir additive manufacturing of small-size component, fills the gap of friction stir additive manufacturing for small-size component forming, solves the problem of low material utilization rate of friction stir additive manufacturing.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology for metallic materials, specifically relating to a counter-rotating friction stirring additive manufacturing apparatus and method. Background Technology

[0002] Friction stir additive manufacturing technology uses frictional heat and plastic deformation to soften metal materials, allowing them to be shaped and formed according to a design without melting. After the component to be processed is cut in the appropriate direction, this technology can be used for layer-by-layer forming. This technology is a novel solid-state additive manufacturing method for metal materials, developed from friction stir welding. Therefore, compared to metal melting additive manufacturing, just as friction stir welding is compared to traditional welding, it has the advantages of not producing thermal stress defects such as cracks and pores. Furthermore, friction stir strengthens the material by refining its grain structure, thus improving the overall mechanical properties of the material.

[0003] However, this technology also has some problems. For example, due to the limitations of the forming principle, defects such as curling and flash will occur at the edge of the additive zone when the additive is stacked layer by layer. Moreover, the layers in the edge zone cannot be well bonded because they are not subjected to upsetting force. Therefore, the current friction stir additive manufacturing can only achieve near-net-shape forming. After friction stir additive manufacturing, the formed blank still needs to be machined, which reduces the material utilization rate. Furthermore, due to the limitations of the existing feeding method, a large area is required for friction stirring in order to make the metal material flow plastically. This results in the large size of the blank formed by friction stir additive manufacturing. For the forming of small-sized components by friction stir additive manufacturing, there is a problem of extremely low material utilization rate. Summary of the Invention

[0004] In view of the above-mentioned existing technical problems and disadvantages, the present invention provides a counter-rotating friction stirring friction additive manufacturing apparatus and method.

[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:

[0006] A counter-rotating friction stir additive manufacturing apparatus includes a friction preheating shoulder, a counter-rotating filament thermoplasticization system, a water-cooled upsetting block, and a substrate. The counter-rotating filament thermoplasticization system includes a pair of coaxial, high-speed rotating disks rotating in opposite directions. The filament is held between the two disks and thermoplasticized due to rotational friction. During processing, the friction preheating shoulder rotates and moves on the substrate or the surface of the additive layer, heating and plasticizing the substrate or additive layer to ensure the bonding between the additive layer and the substrate and the existing additive layer. The counter-rotating filament thermoplasticization system rotates and plasticizes the filament, causing the plasticized metal to fill the gap between the two disks and flow out from below, depositing on the substrate or the existing additive layer processed by the friction preheating shoulder. Then, the water-cooled upsetting block provides upsetting force, causing the plasticized metal to further spread and deposit on the surface of the substrate or the existing additive layer under the action of the upsetting force. At the same time, the temperature of the water-cooled upsetting block can be reduced to control the temperature of the additive layer and improve the quality of the formed component.

[0007] Preferably, the friction preheating shoulder 3 is driven by the machine tool spindle, and the counterrotating wire thermoplasticization system 2 and the water-cooled upsetting block 1 are connected to the spindle by bearings and slide rails, so that the counterrotating wire thermoplasticization system 2 and the water-cooled upsetting block 1 can rotate around the spindle. When the spindle moves along the curve, the counterrotating wire thermoplasticization system 2 and the water-cooled upsetting block 1 are rotated to the tangential rear of the spindle's motion path to achieve the forming of the curvature component.

[0008] Preferably, in the thermoplasticizing system for rotating filaments, each of the two discs is driven by a motor of the same model, and the rotation speed is kept the same so that the angular momentum generated by the rotation of the two discs cancels each other out, thereby ensuring the working accuracy of the mounted CNC machine tool or robotic arm.

[0009] Preferably: the retaining ring of the thermoplasticizing system for the rotating filament is fixed on the slide rail plate, the motor is mounted on the slide rail plate with an open slot, the rotating disc is mounted on the motor and extends into the retaining ring, and the motor is fixed by fastening bolts and the open slot to ensure the clamping position; the filament is fed into the space between the two discs through the circular opening on the retaining ring.

[0010] Preferably, the rotating disc rubs the wire material under the constraint of the retaining ring to prevent the thermoplasticized metal from flying out.

[0011] Preferably, the friction end of the disc in the thermoplasticizing system for the rotating filament should be machined with a spiral groove that rotates toward the axis to ensure sufficient friction of the filament.

[0012] Preferably, the clamping gap of the thermoplasticizing system for rotating filaments is adjustable (1mm to 8mm), allowing it to process filaments of different diameters.

[0013] Preferably, when adjusting the clamping gap of the thermoplasticizing system for rotating filaments, in addition to changing the positions of the two discs and the motor, it is also necessary to replace the retaining ring with one that corresponds to the diameter of the filament feeding opening.

[0014] Preferably, the diameter of the friction preheating shoulder and the width (20mm~30mm) of the water-cooled forging block should be greater than the maximum clamping gap of the thermoplasticizing system for the rotating wire, so as to ensure the temperature of the thermoplasticizing wire deposition area and reduce the generation of defects such as flash and curling.

[0015] Preferably, the water-cooled upsetting block has a beveled surface at the bottom, which allows it to provide a downward upsetting force to the plasticized metal as it moves forward.

[0016] Preferred method: A temperature sensor is installed at the lower end of the water-cooled top forging block to detect the temperature of the additive layer and simultaneously detect the water temperature at the outlet. The temperature of the additive layer is controlled by controlling the water flow rate, which ensures interlayer bonding while avoiding the generation of coarse and uniform defects.

[0017] Preferably, before processing, the height of the friction preheating shoulder should be in contact with the upper surface of the substrate, while the height of the counterrotating wire thermoplasticizing system and the water-cooled forging block should be 4mm away from the upper surface of the substrate; during processing, the counterrotating wire thermoplasticizing system and the water-cooled forging block are pressed down synchronously to ensure that the thermoplasticized wire is forged.

[0018] Preferably, the friction preheating shoulder, the counterrotating wire thermoplasticization system, and the water-cooled upsetting block can not move on the same axis during processing, so as to realize the processing of workpieces with curvature.

[0019] To achieve the above-mentioned objectives, the present invention also provides a method for friction stir additive manufacturing of small-sized components, using the above-mentioned apparatus, and comprising the following steps:

[0020] Step 1: Fix the above-mentioned counter-rotating friction stirring additive manufacturing device on a CNC machine tool, turn on the two motors to make the counter-rotating disc start to rotate, and then introduce the wire. Under the stirring friction of the counter-rotating wire thermoplasticization system, the metal wire gradually thermoplasticizes and begins to fill the gap of the counter-rotating wire thermoplasticization system.

[0021] Step 2: After the filament has been fully thermoplasticized and filled the gap of the thermoplasticization system of the rotating filament, the thermoplasticized filament flows out from below the thermoplasticization system of the rotating filament; open the spindle so that the friction preheating shoulder can start to rotate and frictionally heat the substrate.

[0022] Step 3: The counter-rotating friction stirring additive manufacturing device begins to move forward, and the water-cooled top forging block begins to forge the outflowing thermoplastic filament, causing the thermoplastic filament to diffuse and deposit on the substrate. At the same time, the temperature of the deposited layer and the temperature of the outflowing water are monitored, and the water flow rate is controlled to control the temperature of the deposited layer.

[0023] Step 4: Add material layer by layer according to the preset path until the component is formed.

[0024] Preferred method: If the width of the additive layer needs to be changed during the additive manufacturing process, the device must be stopped and lifted to detach it from the contact with the existing additive layer. After the plasticized metal in the gap of the thermoplasticizing system of the rotating filament has cooled, loosen the motor's fastening bolts and move the motor to both sides of the slide rail. Clean the cooled plasticized metal from the rotating disc, then replace the retaining ring with one that corresponds to the diameter of the filament feed nozzle, and adjust the motor position to the required clamping gap. Finally, secure the motor with the fastening bolts. Additive manufacturing can then continue following the above steps.

[0025] Preferred option: If it is necessary to change the additive material during the additive manufacturing process, the gaps in the thermoplasticization system of the filament should be cleaned according to the above steps before the material is replaced for additive manufacturing.

[0026] Preferably, when the spindle precesses along the curve, the counter-rotating wire thermoplasticizing system 2 and the water-cooled forging block 1 are rotated to the tangential rear of the spindle's motion path to achieve the forming of the curved component.

[0027] The technical advantages of the counter-rotating friction-type small-size stirring friction additive manufacturing device designed in this invention are as follows:

[0028] 1. The counter-rotating friction type small-size stirring friction additive manufacturing device provided by the present invention can realize the stirring friction additive manufacturing of small-size components, fill the gap of stirring friction additive manufacturing for the forming of small-size components, and solve the problem of low material utilization rate in stirring friction additive manufacturing.

[0029] 2. The water-cooled top forging block used in the device provided by the present invention can control the temperature of the additive manufacturing zone, which can avoid defects such as coarse grains and precipitation of reinforcing phase caused by heat accumulation in friction stir additive manufacturing, and improve the comprehensive mechanical properties of the formed component.

[0030] 3. The thermoplasticization system of the rotating filament used in the device provided by the present invention can make the filament fully stirred and thermoplasticized before deposition. Therefore, when multiple filaments are mixed and fed in, a better additive manufacturing effect of alloy components or composite material components can be achieved. Attached Figure Description

[0031] Figure 1 Schematic diagram of a friction stir additive manufacturing device for small-sized components using a counter-rotating friction type.

[0032] Figure 2 Schematic diagram of the wire feeding system for the thermoplasticization of rotating filaments;

[0033] Figure 3 Cross-sectional view of the thermoplasticization system for ferrules;

[0034] Figure 4 Schematic diagram of machine tool loading for a friction stir additive manufacturing device for small-sized components using a counter-rotating friction type.

[0035] Figure 5Schematic diagram of the thermoplasticization system for rotating filaments and the motor loading.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1-Water-cooled top forging block; 2-Thermoplasticization system for counter-rotating wire; 3-Friction preheating shoulder; 4-Base plate;

[0038] 201-Retaining ring; 202-Wire feeding hole; 203-Wire; 204-Rotating disc;

[0039] 501-Slide rail; 502-Open slot; 503-Baffle fixing screw hole; 504-Slide rail plate. Detailed Implementation

[0040] The present invention will be described in detail below with reference to specific embodiments.

[0041] Example 1

[0042] As shown in the figure, this embodiment provides a counter-rotating friction stir additive manufacturing apparatus, which is particularly suitable for the friction stir additive manufacturing of small-sized components. It includes a friction preheating shoulder 3, a counter-rotating wire thermoplasticization system 2, and a water-cooled upsetting block 1.

[0043] The friction preheating shoulder 3 and the water-cooled forging block 1 have arc-shaped curved surfaces with the same curvature as the outer side of the retaining ring 201, allowing them to fit into the counter-rotating wire thermoplasticization system. The counter-rotating wire thermoplasticization system consists of the retaining ring 201 and two rotating disks 204, wherein the diameter of the rotating disks 204 is [missing information]. The thickness is 15mm; the outer diameter of the retaining ring 201 is... Inner diameter is The central angle of the lower opening is 20°; the diameter of the internal water channel is... The inlet and outlet have M5 threaded holes with a depth of 4mm. The distance from the center of the water channel to the forging surface is 7mm. The temperature sensor is installed at the bottom of the water channel, and the data line is led out from the water channel together to detect the temperature of the deposited layer.

[0044] The filament is fed into the counter-rotating filament thermoplasticizing system 2 through the filament feeding hole 202. It is thermoplasticized by the stirring friction between the two rotating discs 204. The rotating discs 204 have spiral grooves on the clamping side to increase frictional heat generation. The thermoplasticized filament will flow out from the opening below the retaining ring 201.

[0045] When the device is loaded onto a CNC machine tool, the friction preheating shoulder 3 is driven by the machine tool spindle. The counterrotating wire thermoplasticization system 2 and the water-cooled upsetting block 1 are connected to the spindle by bearings so that the counterrotating wire thermoplasticization system 2 and the water-cooled upsetting block 1 can rotate around the spindle. When the spindle moves along the curve, the counterrotating wire thermoplasticization system 2 and the water-cooled upsetting block 1 are rotated to the tangential rear of the spindle's motion path to achieve the forming of the curvature component. Furthermore, the rotation angle can be programmed and controlled to achieve the forming of the variable curvature component.

[0046] Example 2

[0047] This embodiment provides a method for manufacturing a component using friction stir additive manufacturing, which includes adding material on a substrate using the friction stir additive manufacturing device described in Embodiment 1; using aluminum alloy as the substrate and 5mm and 1mm aluminum alloy wires as additive materials to achieve the additive effect of a thin-walled aluminum alloy ring component with a thicker bottom and a thinner top.

[0048] Specifically, the friction stir additive manufacturing method provided in this embodiment has the following steps:

[0049] Step 1: Fix the above-mentioned counter-rotating friction stirring additive manufacturing device on a CNC machine tool, fix the substrate on the worktable, turn on the two motors to make the two rotating disks 204 start to rotate, and then pass in 5mm wire. Under the stirring friction of the counter-rotating wire thermoplasticizing system 2, the metal wire gradually thermoplasticizes and begins to fill the gap of the counter-rotating wire thermoplasticizing system 2.

[0050] Step 2: After the filament has been fully thermoplasticized and filled the gap of the thermoplasticization system 2, the thermoplasticized filament flows out from below the thermoplasticization system 2; open the spindle so that the friction preheating shoulder 3 can start to rotate and frictionally heat the substrate.

[0051] Step 3: The counter-rotating friction stirring additive manufacturing device begins to move forward, and the water-cooled top forging block 1 begins to forge the outflowing thermoplastic filament, so that the thermoplastic filament diffuses and deposits on the substrate. At the same time, the temperature of the deposited layer and the temperature of the outflowing water are monitored, and the water flow rate is controlled to control the temperature of the deposited layer.

[0052] Step 4: Add material layer by layer according to the preset path until the aluminum alloy ring part with 5mm wire deposition is formed.

[0053] Step 5: Stop the device and lift it out of contact with the additive layer, and wait for the plasticized metal in the gap of the thermoplasticization system of the rotating filament to cool down.

[0054] Step 6: Loosen the motor fastening bolts and adjust the motor to the maximum clamping gap position. Clean the cooled plasticized metal on the rotating disc 204, then replace the retaining ring 201 of the 1mm diameter wire feed port 202, and adjust the motor position to a clamping gap of 1mm. Finally, fix the motor with the fastening bolts.

[0055] Step 7: Start the spindle and use the friction preheating of the shaft shoulder 3 to rotate and rub the fracture surface generated when the device in Step 5 detaches from the additive layer, making it flat.

[0056] Step 8: Introduce 1mm filament, start the thermoplasticization system 2 for rotating filament, repeat steps 2 and 3, but make the friction preheating shoulder 3 rotate and frictionally heat the 5mm filament to form an additive layer.

[0057] Step 9: Perform additive manufacturing layer by layer according to the preset path until the aluminum alloy ring with 1mm wire deposition is formed. Finally, the additive manufacturing effect of a thin-walled aluminum alloy ring with a thicker bottom and a thinner top is achieved.

[0058] 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 counter-rotating friction stirring friction additive manufacturing apparatus, characterized in that, The system includes a friction preheating shoulder, a counter-rotating filament thermoplasticization system, a water-cooled upsetting block, and a substrate. The counter-rotating filament thermoplasticization system comprises a pair of coaxial, high-speed rotating disks rotating in opposite directions. The filament is held between the two disks and thermoplasticized due to rotational friction. During processing, the friction preheating shoulder rotates and moves on the substrate or the surface of the additive layer, heating and plasticizing the substrate or additive layer to ensure the bonding between the additive layer and the substrate and the additive layer. The counter-rotating filament thermoplasticization system rotates and plasticizes the filament, causing the plasticized metal to fill the gap between the two disks and flow out from below, depositing on the substrate or the additive layer processed by the friction preheating shoulder. Then, the water-cooled upsetting block provides upsetting force, causing the plasticized metal to further spread and deposit on the surface of the substrate or the additive layer under the action of upsetting force. At the same time, the water-cooled upsetting block removes heat from the additive layer to control the temperature of the additive layer.

2. The apparatus according to claim 1, characterized in that, The friction preheating shoulder is driven by the machine tool spindle. The counterrotating wire thermoplasticization system and the water-cooled upsetting block are connected to the spindle by bearings and slide rails, so that the counterrotating wire thermoplasticization system and the water-cooled upsetting block can rotate around the spindle. When the spindle precesses along the curve, the counterrotating wire thermoplasticization system and the water-cooled upsetting block are rotated to the tangential rear of the spindle's motion path to achieve the forming of the curved component.

3. The apparatus according to claim 1, characterized in that, The two discs in the thermoplasticizing system for rotating filaments are each driven by a motor of the same model, and the rotation speed is kept the same so that the angular momentum generated by the rotation of the two discs cancels each other out, thereby ensuring the working accuracy of the CNC machine tool or robotic arm on which it is mounted.

4. The apparatus according to claim 1, characterized in that, The thermoplasticizing system for rotating filaments also includes a retaining ring, which is fixed on a slide rail plate. A motor is mounted on the slide rail plate with an open slot, and a rotating disc is mounted on the motor and extends into the retaining ring. The motor is fixed by fastening bolts and the open slot to ensure the clamping position. The filament is fed into the space between the two discs through the circular opening on the retaining ring and clamped.

5. The apparatus according to claim 4, characterized in that, The rotating disc rubs against the wire material under the constraint of the retaining ring, preventing the thermoplasticized metal from flying out.

6. The apparatus according to claim 1, characterized in that, The friction end of the disc in the thermoplasticizing system for the rotating filament should be machined with a spiral groove that rotates toward the axis to ensure sufficient friction of the filament.

7. The apparatus according to claim 1, characterized in that, The clamping gap of the thermoplasticizing system for rotating filaments is adjustable from 1mm to 8mm, allowing it to process filaments of different diameters.

8. The apparatus according to claim 1, characterized in that, The friction preheating shoulder, the counter-rotating wire thermoplasticization system, and the water-cooled upsetting block can move on different axes during processing to achieve the processing of workpieces with curvature.

9. The additive manufacturing method of the apparatus according to any one of claims 1-8, characterized in that, The steps are as follows: Step 1: Fix the above-mentioned counter-rotating friction stirring friction additive manufacturing device on a CNC machine tool, turn on the two motors to make the counter-rotating disc start to rotate, and then pass in the wire. Under the stirring friction of the counter-rotating wire thermoplasticization system, the metal wire gradually thermoplasticizes and begins to fill the gap of the counter-rotating wire thermoplasticization system. Step 2: After the filament has been fully thermoplasticized and filled the gap of the thermoplasticization system of the rotating filament, the thermoplasticized filament flows out from below the thermoplasticization system of the rotating filament; open the spindle so that the friction preheating shoulder can start to rotate and frictionally heat the substrate. Step 3: The counter-rotating friction stirring friction additive manufacturing device begins to move forward, and the water-cooled top forging block begins to forge the outflowing thermoplastic filament, so that the thermoplastic filament diffuses and deposits on the substrate. At the same time, the temperature of the deposited layer and the temperature of the outflowing water are monitored, and the water flow rate is controlled to control the temperature of the deposited layer. Step 4: Add material layer by layer according to the preset path until the component is formed.

10. The method according to claim 9, characterized in that, As the spindle precesses along the curve, the counter-rotating wire thermoplasticization system and the water-cooled upsetting block are rotated to the tangential rear of the spindle's motion path to achieve the forming of the curved component.

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