A laser additive manufacturing apparatus

Abstract

The application relates to the field of metal addition, and discloses a laser addition manufacturing device, which comprises a metal powder cylinder, a mixed grinding mechanism arranged on the metal powder cylinder, a main preheating mechanism and an auxiliary preheating mechanism arranged on the mixed grinding mechanism, a lifting cylinder, a rotating shaft I, a lifting auger, a connecting cylinder, a rotating shaft II, a grinding head and a grinding seat. The lifting cylinder is fixedly installed on the top inner wall of the metal powder cylinder, the connecting cylinder is fixedly installed between the two lifting cylinders, the rotating shaft I and the rotating shaft II are rotatably installed on the lifting cylinder and the connecting cylinder respectively, and the grinding head is fixedly installed on the bottom of the rotating shaft II. The application has the following advantages and effects: the integrated powder mixing and lifting, online grinding and refinement, main and auxiliary collaborative multi-stage preheating can uniformly refine the metal powder, realize efficient constant-temperature pretreatment, reduce printing defects, and significantly improve the laser addition forming quality and production stability.

Description

Technical Field

[0001] This invention relates to the field of metal additive manufacturing technology, and in particular to a laser additive manufacturing apparatus. Background Technology

[0002] Laser additive manufacturing equipment is a type of 3D printing equipment that uses laser technology to deposit materials, belonging to the additive manufacturing (AM) technology category. It precisely manufactures complex-shaped objects by depositing materials layer by layer according to pre-set design drawings, and is widely used in industries such as aerospace, automotive manufacturing, medical devices, and mold making. Laser evaporation deposition technology is a type of laser additive manufacturing technology. It involves feeding metal powder into a laser printing gun via a powder feeder, where the laser burns the metal powder, causing it to melt and cool on the printing substrate to solidify. This method is suitable for the one-piece molding of complex-shaped metal parts.

[0003] Laser additive manufacturing requires powder feeding mechanisms, such as those disclosed in CN221209890U and CN219443440U. However, these mechanisms fail to adequately mix the metal powder used in laser additive manufacturing, leading to uneven powder composition. Furthermore, some metal powder particles are too large to be properly crushed during feeding, resulting in defects such as porosity, inclusions, and cracks in the formed parts. Additionally, the metal powder cannot be preheated, often being fed directly into the cladding area at room temperature. This significant temperature difference between the powder and the laser molten pool causes rapid heating, leading to thermal stress and splashing, wasting raw materials and exacerbating printing defects.

[0004] Therefore, a laser additive manufacturing device needs to be designed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a laser additive manufacturing apparatus to solve the above-mentioned problems.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a laser additive manufacturing apparatus, comprising:

[0007] A metal powder cylinder, wherein a mixing and grinding mechanism is provided on the metal powder cylinder;

[0008] The mixing and grinding mechanism is equipped with a main preheating mechanism and an auxiliary preheating mechanism;

[0009] The hybrid grinding mechanism includes a lifting cylinder, a first rotating shaft, a lifting auger, a connecting cylinder, a second rotating shaft, a grinding head, and a grinding base;

[0010] The lifting cylinder is fixedly installed on the top inner wall of the metal powder cylinder, the connecting cylinder is fixedly installed between the two lifting cylinders, the first rotating shaft and the second rotating shaft are respectively rotatably installed on the lifting cylinder and the connecting cylinder, the grinding head is fixedly installed at the bottom of the second rotating shaft, and the grinding seat is fixedly installed on the inner wall of the connecting cylinder.

[0011] The main preheating mechanism and the auxiliary preheating mechanism are used in conjunction with the mixing and grinding mechanism.

[0012] A further configuration of the present invention is as follows: the mixing and grinding mechanism further includes a guide pipe, a top frame, a power motor, pulleys and a belt. The guide pipe is fixedly installed on the lifting cylinder and the connecting cylinder. The top frame is fixedly installed on the top of the metal powder cylinder. The power motor is fixedly installed on the top of the top frame. The output end of the power motor is fixedly connected to a rotating shaft. Pulleys are fixedly sleeved on the outer sides of both rotating shafts. A belt is connected between the corresponding two pulleys.

[0013] A further configuration of the present invention is as follows: the main preheating mechanism includes a preheating cylinder, a feeding pipe, a heating chamber, a connecting pipe, a conveying auger, an airflow pipe I, a gas collecting hood, a one-way valve I, a one-way valve II, an airflow pipe II, a connecting shell, a reciprocating screw, a reciprocating screw sleeve, a piston component, and a synchronizing component. The preheating cylinder is fixedly installed between two lifting cylinders. The feeding pipe is fixedly installed at the bottom of the connecting cylinder. The preheating cylinder is fixedly sleeved on the outside of the feeding pipe. A heating chamber is provided inside the preheating cylinder. The connecting pipe is fixedly installed at the bottom of the grinding head. The conveying auger is fixedly sleeved on the outside of the connecting pipe. Airflow pipe I is fixedly installed on the connecting cylinder and the preheating cylinder. Airflow pipe I extends into the interior of the heating chamber. Airflow pipe I is fixed to the gas collecting hood. The system is as follows: the second rotating shaft is rotatably mounted on the gas collecting hood; the second rotating shaft has an airflow channel inside; the outer side of the second rotating shaft has multiple fine holes; the gas collecting hood covers the fine holes; both the first and second one-way valves are mounted on the first airflow pipe; the second airflow pipe is fixedly mounted on the preheating cylinder and the connecting shell, extending into the interior of the heating chamber; the connecting pipe is rotatably mounted on the connecting shell, and the connecting shell communicates with the interior of the connecting pipe; the reciprocating screw is fixedly mounted on the top of the second rotating shaft; the reciprocating screw is connected to the reciprocating screw sleeve in a transmission engagement; the piston is fixedly mounted on the reciprocating screw sleeve, and the piston is in sliding sealing contact with the first airflow pipe; the synchronizing element is fixedly mounted on the top of the reciprocating screw sleeve.

[0014] By adopting the above technical solution, metal powder can be effectively preheated.

[0015] A further configuration of the present invention is as follows: the auxiliary preheating mechanism includes an elastic airbag, a piston strip, a square component, a side rod, a ball bearing, a vertical rod, and a traction component. The elastic airbag is fixedly embedded on the outside of the connecting pipe. Multiple sets of tubes are fixedly arranged on the elastic airbag. The piston strip is slidably and sealedly installed inside the tube. The square component is fixedly connected to the piston strip. The side rod is fixedly installed on the square component. The ball bearing is rotatably installed on the side rod. The ball bearing is in contact with the outside of the traction component. The bottom of the vertical rod is fixedly connected to the traction component. A circular hole is opened at the top of the rotating shaft. The vertical rod is in contact with the inner wall of the circular hole. The top of the vertical rod is fixedly connected to the synchronizing component.

[0016] A further feature of the present invention is that the grinding head is provided with an airflow channel two, and the upright rod passes through the connecting pipe, the airflow channel two, and the airflow channel one in sequence.

[0017] By adopting the above technical solution, the flow of hot air is facilitated.

[0018] A further provision of the present invention is that the piston is vertically slidably mounted on the metal powder cylinder.

[0019] By adopting the above technical solution, the piston component is guided.

[0020] A further feature of the present invention is that a heat-conducting arc-shaped component is fixedly disposed inside the preheating cylinder, one side of the heat-conducting arc-shaped component is connected to the heating cavity, and the other side of the heat-conducting arc-shaped component faces the feed pipe.

[0021] A further feature of the present invention is that an assembly block is fixedly disposed on the metal powder cylinder, an addition tube is fixedly disposed on the top of the metal powder cylinder, and a threaded cap is threadedly connected to the addition tube.

[0022] A further feature of the present invention is that a discharge pipe is fixedly provided at the bottom of the metal powder cylinder, and a valve is installed on the discharge pipe.

[0023] A further feature of the present invention is that an electric heating tube is fixedly disposed inside the heating cavity.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention is equipped with two sets of lifting cylinders and lifting augers, which can synchronously lift and transport powder from different areas inside the metal powder cylinder, and then converge into the connecting cylinder through the guide pipe to mix and break the powder stratification and agglomeration. This allows metal powders of different compositions and densities to be fully fused, ensuring uniform composition of subsequent powder feeding. The rotating shaft drives the grinding head to rotate at high speed, forming a precise grinding gap with the grinding seat. This can continuously crush and refine large particles and agglomerated metal powders, unify the powder particle size specifications, avoid the problem of incomplete melting of large particles, effectively reduce defects such as porosity, inclusions, and cracks in the molded parts, and significantly improve the density and overall quality of laser additive components.

[0026] 2. This invention relies on the main preheating mechanism to construct a closed hot air circulation loop. The heating chamber, reciprocating screw, and piston components work together to achieve hot air circulation. Combined with the connecting pipe made of high thermal conductivity material and the grinding head, the circulating powder is dynamically preheated in all directions. At the same time, the auxiliary preheating mechanism uses the intermittent expansion and compression of the elastic airbag to make the powder adhere to the heat-conducting arc-shaped component, increasing the heat-receiving contact area. The dual-stage preheating works synergistically, resulting in good preheating effect, reducing the temperature difference between the powder and the molten pool, and reducing thermal stress and powder splashing problems. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a laser additive manufacturing device proposed in this invention. Figure 1 .

[0029] Figure 2 This is a schematic diagram of the structure of a laser additive manufacturing device proposed in this invention. Figure 2 .

[0030] Figure 3 This is a partial structural diagram of a laser additive manufacturing device proposed in this invention. Figure 1 .

[0031] Figure 4 This is a partial structural diagram of a laser additive manufacturing device proposed in this invention. Figure 2 .

[0032] Figure 5 This is a partial cross-sectional view of a laser additive manufacturing device proposed in this invention. Figure 1 .

[0033] Figure 6 This is a partial cross-sectional view of a laser additive manufacturing device proposed in this invention. Figure 2 .

[0034] Figure 7 This is a cross-sectional view of the connecting pipe section.

[0035] Figure 8 yes Figure 3 A schematic diagram of part A in the diagram.

[0036] Figure 9 yes Figure 4 A schematic diagram of part B in the diagram.

[0037] Figure 10 yes Figure 5 A schematic diagram of part C in the diagram.

[0038] Figure 11 yes Figure 6 A schematic diagram of part D in the diagram.

[0039] Figure 12 yes Figure 7 A schematic diagram of the structure of part E in the diagram.

[0040] In the diagram, 1 represents a metal powder cylinder;

[0041] 2. Mixing and grinding mechanism; 201. Lifting cylinder; 202. Rotating shaft one; 203. Lifting auger; 204. Connecting cylinder; 205. Guide pipe; 206. Rotating shaft two; 207. Grinding head; 208. Grinding base; 209. Top frame; 210. Power motor; 211. Pulley; 212. Belt;

[0042] 3. Main preheating mechanism; 301. Preheating cylinder; 302. Feeding pipe; 303. Heating chamber; 304. Connecting pipe; 305. Conveying auger; 306. Airflow pipe one; 307. Gas collection hood; 308. One-way valve one; 309. One-way valve two; 310. Airflow pipe two; 311. Connecting shell; 312. Reciprocating screw; 313. Reciprocating screw sleeve; 314. Piston component; 315. Synchronizing component;

[0043] 4. Auxiliary preheating mechanism; 401. Elastic airbag; 402. Piston strip; 403. Square part; 404. Side rod; 405. Ball bearing; 406. Vertical rod; 407. Traction component;

[0044] 5. Assembly block; 6. Material discharge pipe. Detailed Implementation

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood through the specific circumstances.

[0046] The technical solution of the present invention will now be clearly and completely described with reference to specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0047] First Embodiment

[0048] See Figures 1-11 In a first embodiment of the present invention, a laser additive manufacturing apparatus includes:

[0049] include:

[0050] Metal powder cylinder 1, and a mixing and grinding mechanism 2 is provided on the metal powder cylinder 1;

[0051] The mixing and grinding mechanism 2 is equipped with a main preheating mechanism 3 and an auxiliary preheating mechanism 4;

[0052] The mixed grinding mechanism 2 includes a lifting cylinder 201, a first rotating shaft 202, a lifting auger 203, a connecting cylinder 204, a second rotating shaft 206, a grinding head 207, and a grinding seat 208;

[0053] The lifting cylinder 201 is fixedly installed on the top inner wall of the metal powder cylinder 1, the connecting cylinder 204 is fixedly installed between the two lifting cylinders 201, the first rotating shaft 202 and the second rotating shaft 206 are respectively rotatably installed on the lifting cylinder 201 and the connecting cylinder 204, the grinding head 207 is fixedly installed on the bottom of the second rotating shaft 206, and the grinding seat 208 is fixedly installed on the inner wall of the connecting cylinder 204.

[0054] It should be noted that there is a grinding gap between the grinding head 207 and the grinding base 208, which is used for grinding metal powder;

[0055] The main preheating mechanism 3 and the auxiliary preheating mechanism 4 are used in conjunction with the mixing and grinding mechanism 2.

[0056] The mixing and grinding mechanism 2 also includes a guide pipe 205, a top frame 209, a power motor 210, pulleys 211 and belts 212. The guide pipe 205 is fixedly installed on the lifting cylinder 201 and the connecting cylinder 204. The top frame 209 is fixedly installed on the top of the metal powder cylinder 1. The power motor 210 is fixedly installed on the top of the top frame 209. The output end of the power motor 210 is fixedly connected to a rotating shaft 202. The outer sides of the rotating shaft 202 and the rotating shaft 206 are both fixedly fitted with pulleys 211. The two corresponding pulleys 211 are connected by belts 212.

[0057] The main preheating mechanism 3 includes a preheating cylinder 301, a feeding pipe 302, a heating chamber 303, a connecting pipe 304, a conveying auger 305, an airflow pipe 306, a gas collecting hood 307, a one-way valve 308, a one-way valve 309, an airflow pipe 310, a connecting shell 311, a reciprocating screw 312, a reciprocating screw sleeve 313, a piston 314, and a synchronizing element 315. The preheating cylinder 301 is fixedly installed between two lifting cylinders 201, and the feeding pipe 302 is fixedly installed at the bottom of the connecting cylinder 204. The preheating cylinder 301 is fixedly sleeved on the outside of the feeding pipe 302. A heating chamber 303 is provided inside the 301. A connecting pipe 304 is fixedly installed at the bottom of the grinding head 207. A conveying auger 305 is fixedly sleeved on the outside of the connecting pipe 304. An airflow pipe 306 is fixedly installed on the connecting cylinder 204 and the preheating cylinder 301. The airflow pipe 306 extends into the interior of the heating chamber 303. The airflow pipe 306 is fixedly connected to the gas collection hood 307. A rotating shaft 206 is rotatably installed on the gas collection hood 307. It should be noted that the rotating shaft 206 is rotatably installed on the gas collection hood 307 through a sealed bearing, which can ensure the sealing of the rotating parts.

[0058] The rotating shaft 206 has an airflow channel 1 inside, and multiple fine holes are opened on the outside of the rotating shaft 206. The air collection hood 307 covers the fine holes. One-way valve 1 308 and one-way valve 2 309 are both installed on the airflow pipe 1 306. The airflow pipe 2 310 is fixedly installed on the preheating cylinder 301 and the connecting shell 311. The airflow pipe 2 310 extends into the interior of the heating chamber 303. The connecting pipe 304 is rotatably installed on the connecting shell 311. It should be noted that the connecting pipe 304 is rotatably installed on the connecting shell 311 through a sealed bearing, which can ensure the sealing at the rotation position.

[0059] The connecting shell 311 is connected to the inside of the connecting pipe 304. The reciprocating screw 312 is fixedly installed on the top of the rotating shaft 206. The reciprocating screw 312 is connected to the reciprocating screw sleeve 313 through a transmission engagement. It should be noted that the reciprocating screw 312 engages with the slider inside the reciprocating screw sleeve 313 through a reciprocating helical groove on its outer wall, driving the reciprocating screw sleeve 313 to move back and forth.

[0060] The piston component 314 is fixedly installed on the reciprocating screw sleeve 313. The piston component 314 is in sliding sealing contact with the airflow pipe 306. The synchronizing component 315 is fixedly installed on the top of the reciprocating screw sleeve 313.

[0061] It should be noted that the connecting tube 304 is made of copper-chromium-zirconium alloy, which has extremely high thermal conductivity, stable thermal conductivity at high temperatures, high temperature resistance, is not easily oxidized, and has moderate strength and wear resistance, making it suitable for continuous heat conduction and preheating conditions; the grinding head 207 is made of tungsten carbide cemented carbide, which has high hardness, extremely strong wear resistance, resistance to powder erosion and grinding wear, and resistance to high temperature deformation, making it suitable for grinding heads that grind metal powders for a long time; the surface has uniform heat conduction, meeting the heat conduction requirements.

[0062] It should be added that both the preheating cylinder 301 and the metal powder cylinder 1 are provided with wire holes, and the heating wire in the heating chamber 303 is connected to the external power supply and controller through the wire. The wire is a high temperature resistant wire.

[0063] Furthermore, the piston 314 is vertically slidably mounted on the metal powder cylinder 1. It should be noted that this allows the piston 314 to move stably in the vertical direction.

[0064] Furthermore, a heat-conducting arc-shaped component is fixedly installed inside the preheating cylinder 301. One side of the heat-conducting arc-shaped component is connected to the heating chamber 303, and the other side of the heat-conducting arc-shaped component faces the feed pipe 302. An electric heating tube is fixedly installed inside the heating chamber 303. It should be noted that, as Figure 10 As shown, the heat-conducting arc-shaped component is a ring-shaped component that is connected to the heating chamber 303. It is used to conduct the heat in the heating chamber 303 to the heat-conducting arc-shaped component. The preheating cylinder 301 can be made of aluminum silicate ceramic fiber material, which has a good heat insulation effect.

[0065] In this embodiment:

[0066] Metal powder is added to the metal powder cylinder 1. The power motor 210 and the heating element are started. The power motor 210 drives one rotating shaft 202 to rotate. The rotating shaft 202 drives the rotating shaft 206 and the other rotating shaft 202 to rotate through the pulley 211 and belt 212. The rotating shaft 202 drives the lifting auger 203 to rotate, which lifts the metal powder and guides it into the same connecting cylinder 204 through the guide pipe 205, facilitating rapid mixing of the metal powder. The rotating shaft 206 drives the grinding head 207 to rotate. The grinding head 207 cooperates with the grinding seat 208 to grind the metal powder, ensuring the particle size of the metal powder, thereby ensuring the effect of laser additive manufacturing. The heating element heats the inside of the heating chamber 303. In the process, the rotating shaft 206 drives the reciprocating screw 312 to rotate, which in turn drives the reciprocating screw sleeve 313 to move vertically back and forth. The reciprocating screw sleeve 313 drives the piston 314 to move vertically back and forth. When the piston 314 moves upward, it draws out the hot air from the heating chamber 303. The hot air then enters the connecting pipe 304, the second airflow channel, and the first airflow channel in sequence, and enters the gas collection hood 307 through the fine hole. Then it enters the first airflow pipe 306 and passes through the first check valve 308. When the piston 314 moves downward, it guides the hot air back into the heating chamber 303 through the second check valve 309 for heating. This cycle continues, heating the connecting pipe 304 and the grinding head 207. This allows the heat to be evenly introduced into the metal powder, performing preliminary preheating treatment on the metal powder.

[0067] Second Embodiment

[0068] The second embodiment of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0069] Please refer to the following: Figures 7-12 In this embodiment of the laser additive manufacturing apparatus, the auxiliary preheating mechanism 4 includes an elastic airbag 401, a piston strip 402, a square piece 403, a side rod 404, a ball bearing 405, a vertical rod 406, and a traction member 407. The elastic airbag 401 is fixedly embedded on the outside of the connecting pipe 304. Multiple sets of tubes are fixedly arranged on the elastic airbag 401. The piston strip 402 is slidably and sealed inside the tube. The square piece 403 is fixedly connected to the piston strip 402. The side rod 404 is fixedly installed on the square piece 403. The ball bearing 405 is rolled on the side rod 404 and contacts the outside of the traction member 407. The bottom of the vertical rod 406 is fixedly connected to the traction member 407. A circular hole is opened at the top of the rotating shaft 206. The vertical rod 406 contacts the inner wall of the circular hole. It should be noted that a wear-resistant and high-temperature resistant sealing ring is also provided in the circular hole to ensure sealing. The top of the vertical rod 406 is fixedly connected to the synchronizing member 315.

[0070] It should be noted that the elastic airbag 401 is made of high-temperature resistant, high-elasticity, and wear-resistant polymer elastic material, preferably fluororubber, silicone fluororubber, or high-temperature resistant silicone rubber. This type of material has excellent high-temperature resistance and can be adapted to high-temperature environments for powder preheating. At the same time, it has excellent tear resistance, abrasion resistance, and reciprocating deformation resilience. It is not easy to age and crack under long-term compression and stretching.

[0071] Furthermore, an assembly block 5 is fixedly installed on the metal powder cylinder 1, and an addition tube is fixedly installed on the top of the metal powder cylinder 1. A threaded cap is threadedly connected to the addition tube. It should be noted that the assembly block 5 is fixed in a designated position by bolts.

[0072] Furthermore, a discharge pipe 6 is fixedly installed at the bottom of the metal powder cylinder 1, and a valve is installed on the discharge pipe 6. It should be noted that this facilitates the discharge of metal powder.

[0073] In this embodiment: During the upward movement of the reciprocating lead screw sleeve 313, the synchronizing element 315 moves upward synchronously. The synchronizing element 315 then moves the upright rod 406 upward synchronously. The upright rod 406 moves the traction element 407 upward synchronously. The inclined surface on the traction element 407 contacts the ball bearing 405, squeezing it. This causes the side rod 404, square element 403, and piston strip 402 to move synchronously. The piston strip 402 moves within the tube of the elastic air bladder 401, delivering air from the tube into the elastic air bladder 401, causing it to inflate. After inflating, the elastic air bladder 401 pressurizes the metal powder in the feed tube 302 towards the heat-conducting arc-shaped component, ensuring the metal powder fully contacts the component. This further processes the metal powder... Before preheating, the preheating effect is good. When the reciprocating screw sleeve 313 moves down, the traction component 407 moves down synchronously. The balls 405 slowly move towards the center under the action of the inclined surface of the traction component 407 and the force of the elastic air bag 401. The elastic air bag 401 contracts, and some of the metal powder falls down. This process is repeated. At the same time, the grinding head 207 drives the connecting pipe 304 to rotate. The connecting pipe 304 drives the conveying auger 305 to rotate. The conveying auger 305 is located below the elastic air bag 401. The conveying auger 305 conveys the metal powder in the connecting pipe 304 downward. This cycle is repeated, which can fully mix and grind the metal powder. In addition, the metal powder can be efficiently preheated in this process to ensure the use effect of the metal powder.

[0074] Working principle:

[0075] S1: Before operation, the metal powder to be processed is put into the metal powder cylinder 1. The whole device is fixedly installed at the designated station of the laser additive manufacturing equipment by the assembly block 5. The valve on the discharge pipe 6 is closed. The power motor 210 installed on the top of the top frame 209 and the electric heating tube inside the heating chamber 303 are started simultaneously. The output end of the power motor 210 drives the rotating shaft 202 on one side to rotate continuously. The rotating shaft 202 drives the rotating shaft 202 on the other side and the rotating shaft 206 to rotate through the pulley 211 and the belt 212. During the rotation of the rotating shafts 202 on both sides, the lifting auger 203 inside the lifting cylinder 201 is driven to rotate at high speed, continuously lifting and conveying the metal powder deposited at the bottom and piled up around the metal powder cylinder 1. The lifted metal powder is stably introduced into the connecting cylinder 204 through the guide pipe 205. The two materials converge and blend, realizing the initial mixing and homogenization of the metal powder, effectively avoiding problems such as material stratification, local accumulation, and uneven mixing caused by single feeding.

[0076] S2: The rotating shaft 206 drives the grinding head 207 fixed at the bottom to rotate synchronously. The grinding head 207 and the grinding seat 208 fixed on the inner wall of the connecting cylinder 204 cooperate with each other to form a precision grinding gap. The large particles and agglomerated powder that flow into the connecting cylinder 204 are sheared, squeezed and finely ground and crushed. The uniformity of the metal powder particle size is strictly controlled and the excessive large particles are removed. The electric heating tube inside the heating chamber 303 is energized to continuously generate heat. The preheating cylinder 301 is made of high temperature resistant heat insulation material, which can effectively prevent the heat inside the heating chamber 303 from being lost to the outside. The heat accumulated in the heating chamber 303 is directly transferred to the heat-conducting arc-shaped part inside the preheating cylinder 301. The heat-conducting arc-shaped part is arranged to fit the outside of the feeding pipe 302, which can radiate heat evenly to the metal powder falling inside the feeding pipe 302, realizing static fitting preheating.

[0077] S3: A reciprocating lead screw 312 is fixedly installed at the top of the rotating shaft 206. As the rotating shaft 206 rotates, it drives the reciprocating lead screw 312 to rotate synchronously. The reciprocating lead screw 312 is threadedly engaged with the reciprocating lead screw sleeve 313, driving the sleeve to reciprocate vertically. A piston 314, fixed to the outside of the reciprocating lead screw sleeve 313, is slidably sealed inside the airflow pipe 306. The metal powder cylinder 1 provides a vertical sliding limit for the piston 314. When the piston 314 moves upward, a negative pressure is created inside the airflow pipe 306, which in turn causes the heating chamber 303 to... The high-temperature hot air inside is drawn into the connecting pipe 304 through the second airflow pipe 310 and the connecting shell 311. The hot air flows through the second airflow channel inside the grinding head 207 and the first airflow channel inside the second rotating shaft 206 in sequence. Then it is discharged into the gas collection hood 307 through the fine holes opened on the side wall of the second rotating shaft 206. Finally, it enters the first airflow pipe 306 through the first one-way valve 308. When the piston 314 moves downward, it squeezes the gas inside the first airflow pipe 306. With the one-way conduction of the second one-way valve 309, the hot air is returned to the heating chamber 303, forming a closed-loop hot air circuit.

[0078] S4: The connecting pipe 304 is made of high thermal conductivity copper-chromium-zirconium alloy, and the grinding head 207 is made of tungsten carbide hard alloy. Both have excellent thermal conductivity and stable high-temperature structure. Circulating hot air continuously heats the connecting pipe 304 and the grinding head 207, and the heat is quickly transferred to the internally circulating metal powder, realizing dynamic hot air circulation preheating, which greatly improves the uniformity and efficiency of powder preheating. On the basis of the main preheating mechanism 3's cyclic operation, the auxiliary preheating mechanism 4 works synchronously. During the lifting and lowering process of the reciprocating screw sleeve 313, the top-fixed synchronizing component 315 drives the upright 406 to move up and down synchronously. The upright 406 passes through the top round hole of the rotating shaft 206 and drives the traction component 407 to lift and lower in coordination. When the traction component 407 moves upward, its outer inclined surface squeezes the ball bearing 405. The side rod 404 and square piece 403 are pushed to move laterally, causing the piston strip 402 to slide and seal within the tube connected to the elastic airbag 401. This forces the air inside the tube into the cavity of the elastic airbag 401, causing it to expand and deform. The expanded elastic airbag 401 then forms a flexible compression on the metal powder falling inside the feed tube 302, forcibly pushing the powder to fit tightly against the surface of the heat-conducting arc-shaped part, increasing the heat contact area of ​​the powder and enhancing the heat transfer effect. When the traction piece 407 moves downward, the inclined extrusion pressure is released. Relying on the high-temperature resistant and high-elasticity material of the elastic airbag 401, and with the piston strip 402 resetting, the elastic airbag 401 contracts and recovers, and the powder falls naturally and slowly. This repetitive process forms an intermittent extrusion and fabric structure, further optimizing the preheating effect.

[0079] S5: The preheated metal powder continuously falls into the connecting tube 304. The rotating shaft 206 drives the connecting tube 304 to rotate synchronously. The conveying auger 305 fixed on the outside of the connecting tube 304 rotates accordingly, and the processed metal powder is conveyed downward in a quantitative manner at a uniform speed. This cycle is repeated to effectively improve the flowability of the metal powder, eliminate the temperature difference of the powder, and enhance the overall activity of the powder. The overall structure has strong linkage and stable operation, which effectively improves the forming density and overall processing quality of laser additive manufacturing parts.

[0080] The laser additive manufacturing apparatus provided by this invention has been described in detail above. Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A laser additive manufacturing apparatus, characterized in that, include: Metal powder cylinder (1), on which a mixing and grinding mechanism (2) is provided; The mixing and grinding mechanism (2) is provided with a main preheating mechanism (3) and an auxiliary preheating mechanism (4). The hybrid grinding mechanism (2) includes a lifting cylinder (201), a first rotating shaft (202), a lifting auger (203), a connecting cylinder (204), a second rotating shaft (206), a grinding head (207), and a grinding seat (208). The lifting cylinder (201) is fixedly installed on the top inner wall of the metal powder cylinder (1), the connecting cylinder (204) is fixedly installed between the two lifting cylinders (201), the first rotating shaft (202) and the second rotating shaft (206) are respectively rotatably installed on the lifting cylinder (201) and the connecting cylinder (204), the grinding head (207) is fixedly installed at the bottom of the second rotating shaft (206), and the grinding seat (208) is fixedly installed on the inner wall of the connecting cylinder (204); The main preheating mechanism (3) and the auxiliary preheating mechanism (4) are used in conjunction with the mixing and grinding mechanism (2).

2. The laser additive manufacturing apparatus according to claim 1, characterized in that, The mixing and grinding mechanism (2) also includes a guide pipe (205), a top frame (209), a power motor (210), a pulley (211), and a belt (212). The guide pipe (205) is fixedly installed on the lifting cylinder (201) and the connecting cylinder (204). The top frame (209) is fixedly installed on the top of the metal powder cylinder (1). The power motor (210) is fixedly installed on the top of the top frame (209). The output end of the power motor (210) is fixedly connected to a rotating shaft (202). The outer sides of the rotating shaft (202) and the rotating shaft (206) are both fixedly fitted with pulleys (211), and the corresponding two pulleys (211) are connected by a belt (212).

3. The laser additive manufacturing apparatus according to claim 2, characterized in that, The main preheating mechanism (3) includes a preheating cylinder (301), a feeding pipe (302), a heating chamber (303), a connecting pipe (304), a conveying auger (305), an airflow pipe (306), a gas collection hood (307), a one-way valve (308), a one-way valve (309), an airflow pipe (310), a connecting shell (311), a reciprocating screw (312), a reciprocating screw sleeve (313), a piston (314), and a synchronizing element (315). The preheating cylinder (301) is fixedly installed between two lifting cylinders (201), and the feeding pipe (302)... The preheating cylinder (301) is fixedly installed at the bottom of the connecting cylinder (204), and the preheating cylinder (301) is fixedly sleeved on the outside of the feeding pipe (302). A heating chamber (303) is provided inside the preheating cylinder (301). The connecting pipe (304) is fixedly installed at the bottom of the grinding head (207). The conveying auger (305) is fixedly sleeved on the outside of the connecting pipe (304). The first airflow pipe (306) is fixedly installed on the connecting cylinder (204) and the preheating cylinder (301). The first airflow pipe (306) extends into the interior of the heating chamber (303). 06) Fixedly connected to the gas collecting hood (307), the second rotating shaft (206) is rotatably mounted on the gas collecting hood (307). An airflow channel is provided inside the second rotating shaft (206). Multiple fine holes are opened on the outer side of the second rotating shaft (206). The gas collecting hood (307) covers the fine holes. One-way valve one (308) and one-way valve two (309) are both mounted on the first airflow pipe (306). The second airflow pipe two (310) is fixedly mounted on the preheating cylinder (301) and the connecting shell (311). The second airflow pipe two (310) extends to the heating chamber (303). Inside, the connecting pipe (304) is rotatably mounted on the connecting shell (311), and the connecting shell (311) is connected to the inside of the connecting pipe (304). The reciprocating screw (312) is fixedly mounted on the top of the rotating shaft (206). The reciprocating screw (312) is connected to the reciprocating screw sleeve (313) in a transmission fit. The piston (314) is fixedly mounted on the reciprocating screw sleeve (313). The piston (314) is in sliding sealing contact with the airflow pipe (306). The synchronizing element (315) is fixedly mounted on the top of the reciprocating screw sleeve (313).

4. The laser additive manufacturing apparatus according to claim 3, characterized in that, The auxiliary preheating mechanism (4) includes an elastic airbag (401), a piston strip (402), a square component (403), a side rod (404), a ball bearing (405), a vertical rod (406), and a traction component (407). The elastic airbag (401) is fixedly embedded on the outside of the connecting pipe (304). Multiple sets of tubes are fixedly arranged on the elastic airbag (401). The piston strip (402) is slidably and sealingly installed in the tube. The square component (403) and the piston strip (402) are connected. The side rod (404) is fixedly installed on the square piece (403), the ball (405) is rolled on the side rod (404), the ball (405) is in contact with the outer side of the traction member (407), the bottom of the upright rod (406) is fixedly connected to the traction member (407), the top of the rotating shaft (206) is provided with a round hole, the upright rod (406) is in contact with the inner wall of the round hole, and the top of the upright rod (406) is fixedly connected to the synchronizing member (315).

5. The laser additive manufacturing apparatus according to claim 4, characterized in that, The grinding head (207) is provided with an airflow channel two, and the upright (406) passes through the connecting pipe (304), the airflow channel two and the airflow channel one in sequence.

6. The laser additive manufacturing apparatus according to claim 3, characterized in that, The piston (314) is vertically slidably mounted on the metal powder cylinder (1).

7. The laser additive manufacturing apparatus according to claim 3, characterized in that, A heat-conducting arc-shaped component is fixedly installed inside the preheating cylinder (301). One side of the heat-conducting arc-shaped component is connected to the heating chamber (303), and the other side of the heat-conducting arc-shaped component faces the feed pipe (302).

8. The laser additive manufacturing apparatus according to claim 1, characterized in that, An assembly block (5) is fixedly installed on the metal powder cylinder (1), and an addition tube is fixedly installed on the top of the metal powder cylinder (1), with a threaded cap threadedly connected to the addition tube.

9. The laser additive manufacturing apparatus according to claim 1, characterized in that, The bottom of the metal powder cylinder (1) is fixedly provided with a discharge pipe (6), and a valve is installed on the discharge pipe (6).

10. A laser additive manufacturing apparatus according to claim 3, characterized in that, An electric heating tube is fixedly installed inside the heating chamber (303).

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