Liquid supporting point array laser area printing additive manufacturing equipment and method thereof

Abstract

The invention belongs to the technical field of additive manufacturing, and particularly relates to liquid supporting point array laser area printing additive manufacturing equipment and a method thereof.The liquid supporting point array laser area printing additive manufacturing equipment comprises an optical bin, an optical module is arranged in the optical bin, and the optical bin is used for integrating, homogenizing and patterning multiple laser beams and conveying the laser beams into a forming bin; a forming platform is arranged in the forming bin, a forming opening is formed in the forming platform, and a forming base plate is installed at the forming opening. A forming cavity is formed below the forming platform, liquid is contained in the forming cavity, the liquid level of the liquid is flush with the surface of a forming base plate at the beginning of printing, and a powder laying assembly is installed in the forming bin and used for laying metal powder to the surface of the liquid; a forming base body is fixedly connected to the lower surface of the forming base plate, the other end of the forming base body penetrates out of the forming cavity to be connected with a first driving assembly, and the first driving assembly drives the forming base body and drives the forming base plate to move up and down. The use amount of the forming powder can be remarkably reduced, and the forming efficiency and the powder utilization rate are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and particularly relates to a liquid-supported lattice laser area printing additive manufacturing device and method thereof. Background Art

[0002] Additive manufacturing is a new manufacturing technology, which is different from the traditional subtractive manufacturing methods of cutting or removing materials. The core concept of additive manufacturing is to gradually build a three-dimensional object by layer-by-layer stacking or adding materials. Laser powder bed fusion technology is one of the popular additive manufacturing technologies for metal materials. Its basic principle is: a certain thickness of metal powder is spread flat on a forming substrate, and a focused laser beam is used to locally melt the metal powder. Subsequently, the forming substrate is lowered, and a new powder layer is deposited on the previously remelted powder layer. By repeating the above steps of platform movement, powder recoating, and laser exposure in a cyclic manner, a three-dimensional object is created in a layered manner from a computer-aided design model. This technology can manufacture various metal and alloy parts with complex structures.

[0003] However, in the above laser powder bed fusion technology, as the number of printed layers increases, the area of the powder bed increases, resulting in a sharp increase in the usage of metal powder. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a liquid-supported lattice laser area printing additive manufacturing device and method thereof.

[0005] The present invention is specifically realized through the following technical solutions.

[0006] A liquid-supported lattice laser area printing additive manufacturing device includes: An optical chamber, in which an optical component is installed. The optical component is used to unify, homogenize, and pattern multiple laser beams and convey them into the forming chamber. During specific installation, an optical mounting plate is arranged in the optical chamber, and the optical component is fixed on the optical mounting plate.

[0007] A forming platform is arranged in the forming chamber. A forming opening is provided on the forming platform, and a forming substrate is installed at the forming opening. The forming substrate can move up and down relative to the forming opening. During specific installation, the forming chamber is arranged below the optical chamber. A forming chamber bottom plate is arranged in the forming chamber, and a groove-shaped forming platform is provided on the forming chamber bottom plate. A forming cavity is arranged on the lower surface of the forming platform. When the forming substrate moves downward, it enters the forming cavity. One end of a forming base body is fixedly connected to the lower surface of the forming substrate, and the other end of the forming base body passes through the forming cavity and is connected to a first driving component. The first driving component is used to drive the forming base body and drive the forming substrate to move up and down relative to the forming opening.

[0008] A powder spreading component is installed inside the forming chamber, and a liquid level adjusting component is connected to the outside of the forming cavity. During printing, the forming cavity is filled with liquid, and the liquid level is flush with the surface of the forming substrate at the beginning of printing. During the printing process, the forming substrate moves downward relative to the forming orifice, and the liquid level adjusting component keeps the liquid level unchanged. The powder spreading component spreads metal powder onto the liquid surface, and the laser output by the optical component melts the metal powder on the liquid surface. Since the unprinted metal powder on the liquid surface does not need to drop, when spreading powder for the next layer, only the metal powder in the printing area needs to be supplemented, thus reducing the amount of metal powder used. The types of liquid include, but are not limited to, low melting point alloy materials such as tin-based alloys, bismuth-based alloys, zinc-based alloys, indium-based alloys, and non-metallic materials such as phenolic resins, acrylates, and asphalt. It is required that the liquid material does not interfere with the normal forming of the metal powder. In addition, the contact between the forming matrix and the forming cavity is sealed to prevent liquid leakage.

[0009] Preferably, to ensure that the liquid can provide a supporting effect, it is required that the density of the metal powder is less than that of the liquid. The metal powder floats on the liquid surface and forms a wet layer and a dry layer. The wet layer is immersed in the liquid, and the dry layer is above the wet layer.

[0010] Preferably, a liquid inlet and a liquid outlet are provided on the forming cavity, a filter screen is installed at the liquid outlet, and a heating device is installed inside the forming cavity; the liquid level adjusting component includes a liquid level adjusting chamber, the bottom of the forming cavity is connected to the liquid level adjusting chamber, a liquid level adjusting motor is installed at one end of the liquid level adjusting chamber away from the forming cavity, a baffle is installed inside the liquid level adjusting chamber, and the liquid level adjusting motor is used to drive the baffle to approach or move away from the forming cavity, thereby adjusting the liquid level height inside the forming cavity. When the baffle approaches the forming cavity, the liquid level inside the forming cavity rises, and when the baffle moves away from the forming cavity, the liquid level inside the forming cavity drops.

[0011] In the existing laser powder bed melting technology, the limited diameter of the laser beam results in the inability to rapidly improve the printing efficiency. For this reason, the present invention designs an optical system that can achieve the unification, homogenization, and patterning of multiple laser beams. Preferably, the optical component includes an array laser, an entrance focusing lens, a first lens, a second lens, a microlens array, a third lens, a fourth lens, a one-way reflector, an addressable light valve, a signal laser, a polarization reflector, a fifth lens, a sixth lens, an exit focusing lens, and a galvanometer scanner.

[0012] The array laser is used to emit laser light. A first optical fiber interface is provided on the array laser. The emitted laser light converges into a large-diameter laser in the first optical fiber interface and is conducted through the first optical fiber into the entrance focusing lens. The entrance focusing lens is used to collimate the laser light. The laser light emitted from the entrance focusing lens passes through the focal point of the first lens and enters the first lens perpendicularly to the surface of the first lens. The first lens and the second lens are placed opposite to each other, and the focal points of both the first lens and the second lens are on the laser propagation path. The microlens array is placed perpendicular to the laser path and is used to homogenize the laser intensity. After the laser light exits the microlens array perpendicularly, it enters the third lens and the fourth lens through the focal points of the third lens and the fourth lens.

[0013] The one-way mirror is placed on the laser propagation path, and the incident angle of the laser with the one-way mirror is 45°. After passing through the one-way mirror, the laser is perpendicularly incident on one side surface of the addressable light valve. The signal laser is placed on the other side of the addressable light valve. A low-frequency laser with a specific shape is emitted from the signal laser and is perpendicularly incident on the other side surface of the addressable light valve. The addressable light valve receives the low-frequency laser from the signal laser and locally polarizes the reflected laser when reflecting the laser passing through the one-way mirror on one side.

[0014] The laser is reflected from one side surface of the addressable light valve, is incident on the other side of the one-way mirror at an angle of 45° with the surface of the one-way mirror and is reflected. The reflected laser is incident on the surface of the polarization mirror at an angle of 45°. At this time, the laser in the region that is polarized when reflected by the addressable light valve will be reflected by the polarization mirror, and the laser in the non-polarized region will pass through the polarization mirror.

[0015] The polarized laser is reflected by the polarization mirror and then perpendicularly enters the fifth lens, the sixth lens and the exit focusing lens. After passing through the exit focusing lens, the laser is input into the galvanometer and finally the laser is hit on the metal powder to be melted through the deflection of the galvanometer.

[0016] Preferably, the optical component further includes a total reflection mirror, a recycling adjustment mirror and a laser recycler. The non-polarized laser passes through the polarization mirror and is incident on the surface of the total reflection mirror at an angle of 45°, and is reflected by the total reflection mirror and perpendicularly enters the recycling adjustment mirror. The laser is input into the laser recycler through the third optical fiber interface and the third optical fiber. The optical component further includes: an industrial camera and a camera mount. The industrial camera is installed in the camera mount to photograph the printing process.

[0017] Preferably, the part of the forming matrix located outside the forming cavity is movably installed on the Z-axis motion guide rail and can move up and down along the Z-axis motion guide rail under the driving action of the first driving component. The first driving component includes a collar, a first lead screw, and a servo motor. The other end of the forming matrix forms a first ball screw motion pair with the first lead screw through the collar. The servo motor is connected to the first lead screw through a first coupling. The servo motor drives the forming substrate to move along the Z-axis motion guide rail through the first ball screw motion pair. In the present invention, the servo motor and the ball screw are used for transmission, which can achieve the precise movement of the forming matrix and effectively prevent metal powder from falling through the gap between the forming matrix and the forming cavity and affecting the transmission.

[0018] Preferably, the powder spreading component includes a doctor blade. The doctor blade is located above the forming platform. X-axis motion guide rails are respectively installed on both sides of the forming platform. The doctor blade moves along the X-axis motion guide rail under the driving action of the second driving component. A powder storage bin is installed in the optical chamber. The top of the doctor blade is communicated with the powder storage bin through a powder dropping pipe.

[0019] The inside of the doctor blade includes an upper chamber and a lower powder dropping bin. The upper chamber is equally divided in the length direction of the doctor blade with a plurality of powder dropping holes. Metal powder enters the powder dropping bin through the plurality of powder dropping holes. A blade is installed at the bottom of the powder dropping bin. Powder dropping ports are respectively opened on both sides of the bottom of the powder dropping bin on both sides of the blade. The metal powder in the powder dropping bin drops onto the liquid surface through the powder dropping ports and is evenly spread on the liquid surface during the movement of the blade.

[0020] A powder collecting hole is provided on the forming platform, and a powder collecting funnel is installed below the powder collecting hole. During the powder spreading process, the excess metal powder on the liquid surface falls through the powder collecting hole, converges through the powder collecting funnel, and then falls into the powder recovery box through the powder collecting pipe.

[0021] Preferably, a spiral blade conveying shaft is installed inside the powder dropping pipe. A coil is provided at the upper end of the spiral blade conveying shaft. A magnetic levitation driving motor is installed at the upper end of the powder dropping pipe. The magnetic levitation driving motor drives the coil to rotate and drives the spiral blade conveying shaft to rotate, quantitatively conveying the metal powder from the powder storage bin to the upper chamber inside the doctor blade.

[0022] A powder spreading motor is installed on one side of the powder dropping bin inside the doctor blade. A spiral conveying shaft is arranged inside the powder dropping bin. One end of the spiral conveying shaft is connected to the output shaft of the powder spreading motor, and the other end is rotatably connected to the side wall of the powder dropping bin. Specifically, when installed, a motor installation bin is provided on one side of the powder dropping bin inside the doctor blade. The powder spreading motor is installed in the motor installation bin. One end of the spiral conveying shaft passes through the side wall of the powder dropping bin and enters the motor installation bin, and is connected to the output shaft of the powder spreading motor through a third coupling. The other end of the spiral conveying shaft is connected to a second bearing, and the second bearing is installed in the second bearing seat on the side wall of the powder dropping bin.

[0023] Preferably, the second driving assembly includes a lead screw nut, a second lead screw, and an X-direction movement motor. Both ends of the scraper are fixedly provided with lead screw nuts, and each lead screw nut is engaged with a second lead screw to form a second ball screw pair. One end of the second lead screw is connected to the X-direction movement motor through a second coupling, and the X-direction movement motor drives the scraper to move back and forth along the X-direction movement guide rail through the second ball screw pair.

[0024] Preferably, an oxygen content detection device is installed on the side wall of the forming chamber. When the oxygen content in the forming chamber is higher than the set value, the equipment will stop working and trigger an alarm until the oxygen content drops below the set value.

[0025] The present invention also provides a liquid-supported dot matrix laser area printing additive manufacturing method, including the following steps: When starting to work, use the first driving assembly to drive the forming substrate to move, so that the forming substrate is flush with the surface of the forming platform, add liquid into the forming chamber, and make the liquid level flush with the surface of the forming substrate.

[0026] Through the powder spreading assembly, the metal powder is evenly spread on the liquid surface of the liquid.

[0027] After the powder spreading is completed, the laser output by the optical assembly melts the metal powder on the liquid surface; after melting the metal powder in all areas of this layer, use the first driving assembly to drive the forming substrate to descend a certain height, use the liquid level adjusting assembly to keep the liquid level unchanged, wait for the next layer of powder spreading, and then melt the newly spread metal powder. Repeat the steps of descending the forming substrate, powder spreading, and melting until the printing of the part is completed.

[0028] After the printing is completed, drain the liquid from the forming chamber, raise the forming substrate above the forming platform, take out the printed part, and clean the metal powder in the forming chamber.

[0029] Compared with the prior art, the present invention has the following beneficial effects: The present invention is provided with a forming chamber. Inside the forming chamber, there is a forming platform. The forming platform is provided with a forming opening, and a forming substrate is installed at the forming opening. The forming substrate can move up and down relative to the forming opening; the lower surface of the forming platform is provided with a forming cavity. When the forming substrate moves downward, it enters the forming cavity. During printing, the forming cavity is filled with liquid, and the liquid level of the liquid is flush with the surface of the forming substrate at the beginning of printing. The metal powder is spread on the liquid surface. During the printing process, the liquid level is kept unchanged by the liquid level adjusting assembly, and the forming substrate moves downward relative to the forming opening, so that each powder spreading during the printing process is spread on the liquid surface. The present invention uses liquid to replace the traditional powder support. Since the unprinted metal powder on the liquid surface does not need to descend, when spreading powder for the next layer, only the metal powder in the printing area needs to be supplemented. Therefore, the amount of powder used as support during the forming process is reduced, and the powder utilization rate is improved.

[0030] The present invention also designs an optical system, which can realize the unification, homogenization and patterning of multiple laser beams. Compared with the existing optical systems, the present invention adopts an array laser, and the output laser has a higher unit energy. The synthesized laser beam has a large diameter, can clad a larger area per unit time, and has a higher forming rate. The present invention uses multiple groups of lenses, which has higher precision in the process of laser patterning and laser cladding, can adjust the shape and size of the laser spot according to the printing area, and the minimum spot size is not greater than 10 , and has higher forming precision compared with the existing processes.

[0031] The present invention installs the optical device in a separate optical chamber, effectively preventing the interference of metal powder dust in the forming chamber. Description of the Drawings

[0032] Figure 1 is a schematic diagram of the overall structure of a liquid-supported lattice laser area printing additive manufacturing device provided by the present invention.

[0033] Figure 2 is a schematic diagram of the internal structure of the optical chamber.

[0034] Figure 3 is the Figure 2 schematic diagram of the internal structure of the optical chamber after rotation.

[0035] Figure 4 is a schematic diagram of the internal structure of the forming chamber.

[0036] Figure 5 is a schematic diagram of the internal structure of the powder dropping tube.

[0037] Figure 6 is a schematic diagram of the internal structure of the powder spreading assembly.

[0038] Figure 7 is a schematic diagram of the structures installed above and below the bottom plate of the forming chamber.

[0039] Figure 8 is a schematic diagram of the structure of the metal powder layer on the liquid surface.

[0040] Figure 9 is a schematic diagram of the internal structure of the machine tool base.

[0041] Description of the Reference Numerals: 1. Optical Chamber, 101. Optical Mounting Plate, 102. Array Laser, 103. First Fiber Optic Interface, 104. First Optical Fiber, 105. Entrance Focusing Mirror, 106. First Lens, 107. Second Lens, 108. Microlens Array, 109. Third Lens, 110. Fourth Lens, 111. Unidirectional Reflector, 112. Addressable Light Valve, 113. Signal Laser, 114. Polarization Reflector, 115. Fifth Lens, 116. Sixth Lens, 117. Exit Focusing Mirror, 118. Second Optical Fiber, 119. Second Fiber Optic Interface, 120. Galvanometer Scanner, 121. Galvanometer Scanner Mount, 122. Total Reflecting Mirror, 123. Recycling and Adjusting Mirror, 124. Third Fiber Optic Interface, 125. Third Optical Fiber, 126. Laser Recoverer, 127. Industrial Camera, 128. Camera Mount, 129. Powder Storage Bin, 130. Outer Shell, 131. First Operation Door.

[0042] 2. Forming Chamber, 201. Forming Chamber Bottom Plate, 202. Forming Platform, 203. Forming Substrate, 204. Powder Collection Hole, 205. Forming Chamber Side Wall, 206. Oxygen Content Detection Device, 207. X - Direction Movement Motor, 208. First Motor Mount, 209. Second Coupling, 210. Second Lead Screw, 211. X - Direction Movement Guide Rail, 212. Scraper, 213. First Bearing, 214. First Bearing Block, 215. Right Limit Switch, 216. Left Limit Switch, 217. Ventilation Opening, 218. Powder Dropping Pipe, 219. Part, 220. Screw Blade Conveyor Shaft, 221. Maglev Drive Motor, 222. Coil, 223. Powder Collection Interface, 224. Lead Screw Nut, 225. Powder Spreading Motor, 226. Third Coupling, 227. Screw Conveyor Shaft, 228. Second Bearing, 229. Second Bearing Block, 230. Blade Edge, 231. Powder Dropping Hole, 232. Powder Dropping Bin, 233. Motor Installation Chamber, 234. Forming Cavity, 235. Liquid Inlet, 236. Liquid Outlet, 237. Filter Screen, 238. Liquid Level Adjustment Chamber, 239. Liquid Level Adjustment Motor, 240. Baffle, 241. Heating Device, 242. Liquid, 243. Metal Powder Layer, 244. Wet Layer, 245. Dry Layer, 246. Second Operation Door, 247. Forming Substrate.

[0043] 3. Machine Tool Base, 301. Powder Collection Hopper, 302. Powder Collection Pipeline, 303. Powder Recycling Box, 304. Machine Tool Base Side Wall, 305. Bottom Plate, 306. Z - Axis Movement Guide Rail, 308. Collar, 309. First Lead Screw, 310. First Coupling, 311. Servo Motor, 312. Second Motor Mount, 313. Third Operation Door. Detailed Implementation Modes

[0044] To enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention will be further described below in conjunction with specific embodiments and the accompanying drawings. However, the specific embodiments cited do not limit the present invention.

[0045] The present invention provides a liquid-supported dot matrix laser area printing additive manufacturing device, including: An optical chamber 1, in which an optical component is installed. The optical component is used to unify, homogenize, and pattern multiple laser beams and convey them into the forming chamber 2.

[0046] A forming platform 202 is arranged in the forming chamber 2. A forming opening is provided on the forming platform 202, and a forming substrate 203 is installed at the forming opening. The forming substrate 203 can move up and down relative to the forming opening.

[0047] A forming cavity 234 is arranged on the lower surface of the forming platform 202. When the forming substrate 203 moves downward, it enters the forming cavity 234. One end of a forming base body 247 is fixedly connected to the lower surface of the forming substrate 203, and the other end of the forming base body 247 passes through the forming cavity 234 and is connected to a first driving component. The first driving component is used to drive the forming base body 247 and drive the forming substrate 203 to move up and down relative to the forming opening.

[0048] A powder spreading component is installed in the forming chamber 2. The outside of the forming cavity 234 is communicated with a liquid level adjusting component. During printing, the forming cavity 234 is filled with a liquid 242, and the liquid level of the liquid 242 is flush with the surface of the forming substrate 203 at the beginning of printing. During the printing process, the forming substrate 203 moves downward relative to the forming opening, and the liquid level adjusting component is used to keep the liquid level of the liquid 242 unchanged. The powder spreading component is used to spread metal powder onto the liquid surface. The laser output by the optical component melts the metal powder on the liquid surface. Each powder spreading during the printing process is spread on the liquid surface. Using liquid instead of traditional powder support reduces the amount of powder used as support during the forming process and improves the utilization rate of metal powder.

[0049] The liquid-supported dot matrix laser area printing additive manufacturing method provided by the present invention includes the following steps: When starting to work, use the first driving component to drive the forming base body 247 to move, so that the forming substrate 203 is flush with the surface of the forming platform 202, add the liquid 242 into the forming cavity 234, and make the liquid level flush with the surface of the forming substrate 203.

[0050] Through the powder spreading component, uniformly spread the metal powder on the liquid surface of the liquid 242.

[0051] After powder spreading is completed, the laser output by the optical component melts the metal powder on the liquid surface; after melting the metal powder in all areas of this layer, the first driving component is used to drive the forming substrate 203 to descend a certain height, and the liquid surface adjusting component is used to keep the liquid surface unchanged, waiting for powder spreading in the next layer, and then melting the newly laid metal powder. The steps of descending the forming substrate 203, powder spreading, and melting are repeated in a cycle until the printing of the part is completed.

[0052] After printing is completed, the liquid 242 is discharged from the forming cavity 234, the forming substrate 203 rises above the forming platform 202, and the printed part is taken out and the metal powder in the forming cavity 234 is cleaned.

[0053] The content of the present invention will be specifically described below.

[0054] As Figure 1 shown, the liquid-supported dot matrix laser area printing additive manufacturing equipment provided by the present invention includes an optical chamber 1, a forming chamber 2, and a machine tool base 3.

[0055] As Figure 2 and Figure 3 shown, an optical mounting plate 101 is arranged in the optical chamber 1, and a dust-free environment for the operation of optical devices is ensured in the optical chamber 1. A first operation door 131 is arranged on the outer shell 130 of the optical chamber 1, which is convenient for adjusting the positions of various optical elements and performing dust removal operations inside. The optical mounting plate 101 is made of a transparent material. It should be noted that Figure 2 the positions of the various optical elements shown are corresponding to the positions of the components shown in Figure 1 , Figure 4 In order to clearly display the various optical elements in Figure 2 , after Figure 2 is rotated, Figure 3 is obtained.

[0056] An optical component is fixed on the optical mounting plate 101. The optical component is used to unify, homogenize, and pattern multi-laser beams and transport them into the forming chamber 2. The optical component includes an array laser 102, an entrance focusing lens 105, a first lens 106, a second lens 107, a microlens array 108, a third lens 109, a fourth lens 110, a unidirectional reflector 111, an addressable light valve 112, a signal laser 113, a polarization reflector 114, a fifth lens 115, a sixth lens 116, an exit focusing lens 117, a galvanometer 120, a galvanometer mount 121, a total reflector 122, a recovery adjustment mirror 123, a laser recycler 126, and a camera mount 128. A powder storage bin 129 is also installed on the optical mounting plate 101.

[0057] Multiple laser beams are emitted from the array laser 102, converge into a large-diameter laser in the first optical fiber interface 103, and are conducted through the first optical fiber 104 into the entrance focusing lens 105. The large-diameter laser is collimated in the entrance focusing lens 105. After the large-diameter laser exits the entrance focusing lens 105, it is successively vertically incident on the first lens 106, the second lens 107, the microlens array 108, the third lens 109, and the fourth lens 110. The laser exiting the entrance focusing lens 105 passes through the focal point of the first lens 106 and is incident perpendicularly to the surface of the first lens 106. The first lens 106 and the second lens 107 are placed opposite to each other, and the focal points of the first lens 106 and the second lens 107 are both on the laser propagation path. The microlens array 108 is placed perpendicular to the laser path and is used to homogenize the laser intensity. The first lens 106 and the second lens 107 form a lens group. After the large-diameter laser is incident, the diameter of the laser beam will shrink. After the laser diameter shrinks and is perpendicularly incident into the microlens array 108, the laser intensities at different positions of the laser beam are homogenized. The laser exiting the microlens array 108 is a homogenized laser with equal laser intensities at each position within the beam.

[0058] The homogenized laser exits from the surface of the microlens array 108 and is perpendicularly incident into the lens group composed of the third lens 109 and the fourth lens 110. The lens group composed of the third lens 109 and the fourth lens 110 has an amplifying effect on the diameter of the laser beam. After the laser beam exits from the fourth lens 110, the diameter increases. The large-diameter laser beam penetrates the one-way mirror 111 from left to right and is perpendicularly incident on the left side surface of the addressable light valve 112. At the same time, the signal laser 113 emits a low-frequency laser with a specific shape, and the low-frequency laser is perpendicularly incident on the right side surface of the addressable light valve 112. The addressable light valve 112 receives the low-frequency laser beam with a specific shape from the signal laser 113 and produces a polarization effect on the laser at the corresponding position when reflecting the large-diameter laser on the left side, that is, when the large-diameter laser penetrating the one-way mirror 111 is reflected by the addressable light valve 112, the large-diameter laser can be divided into polarized laser and non-polarized laser inside.

[0059] The large-diameter laser is reflected by the left side of the addressable light valve 112 and then incident on the right side of the one-way mirror 111, and is reflected again to the polarization mirror 114. When incident on the polarization mirror 114, lasers with different polarization states will undergo different operations, and the polarization mirror 114 will reflect or transmit according to the different polarization conditions of the incident lasers on its surface. The laser that generates polarization when reflected by the addressable light valve 112 will be reflected by the polarization mirror 114, and the laser that does not generate polarization will penetrate the polarization mirror 114. Specifically, the laser that generates polarization will be reflected by the polarization mirror 114 and incident on the lens group composed of the fifth lens 115 and the sixth lens 116. After passing through the lens group, the diameter of the large-diameter laser will be reduced. After being refocused by the exit focusing mirror 117, it is input into the galvanometer 120 through the second optical fiber 118 and the second optical fiber interface 119, and finally the laser is hit on the surface of the part 219 located on the forming substrate 203 after being deflected by the galvanometer 120. The galvanometer 120 is installed in the galvanometer mount 121. The laser that does not generate polarization passes through the polarization mirror 114 and is incident on the surface of the total reflection mirror 122 at an angle of 45°, and is reflected by the total reflection mirror 122 and vertically incident into the recycling and adjusting mirror 123, and the laser is input into the laser recycler 126 through the third optical fiber interface 124 and the third optical fiber 125.

[0060] Through the unification, homogenization and patterning of multiple laser beams, the present invention can adjust the shape and size of the laser spot according to the printing area, and the minimum spot size is not greater than 10 , and has higher forming accuracy compared with the existing process.

[0061] The industrial camera 127 is installed in the camera mount 128 and can photograph the forming process. It should be noted that a first through hole is provided on the optical mounting plate 101, and the industrial camera 127 photographs the forming process through the first through hole. When the laser hits the surface of the part 219 on the forming substrate 203, the laser hits the surface of the part 219 through the second through hole provided on the optical mounting plate 101.

[0062] Such as Figure 4As shown in the figure, the forming chamber 2 is located below the optical chamber 1. A forming chamber bottom plate 201 is provided in the forming chamber 2. A groove-shaped forming platform 202 is formed on the forming chamber bottom plate 201. A forming opening is formed in the center of the forming platform 202. A forming substrate 203 is provided at the forming opening. The forming substrate 203 can move up and down relative to the forming opening. The powder collection hole 204 is on the left side of the forming opening. An X-direction movement guide rail 211 is installed on each of the front and rear sides of the forming platform 202. A ventilation port 217 is installed under the X-direction movement guide rail 211. The powder spreading assembly includes a scraper 212. The scraper 212 is installed on the X-direction movement guide rail 211. The scraper 212 moves along the X-direction movement guide rail 211 under the drive of the second drive assembly. The second drive assembly includes a lead screw nut 224, a second lead screw 210, and an X-direction movement motor 207. The X-direction movement motor 207 drives the scraper 212 to move left and right along the X-direction movement guide rail 211 through a second ball screw pair. Specifically, the second ball screw pair includes a lead screw nut 224 and a second lead screw 210. The right end of the second lead screw 210 is connected to the X-direction movement motor 207 installed in the first motor base 208 through a second coupling 209. The left end is connected to the first bearing seat 214 together with the first bearing 213. The two ends of the scraper 212 are respectively fixed with a lead screw nut 224. Each lead screw nut 224 cooperates with a second lead screw 210 to form a spiral raceway. The spiral raceway contains balls. The X-direction movement motor 207 drives the second lead screw 210 to rotate and drives the scraper 212 to move linearly along the second lead screw 210 through the balls and the lead screw nut 224, that is, to move left and right along the X-direction movement guide rail 211.

[0063] There are a right limit switch 215 and a left limit switch 216 on both sides of the scraper 212 respectively. When the scraper 212 moves to the limit position and triggers the corresponding limit switch, the X-direction movement motor 207 will be forced to stop working to ensure that the scraper 212 is not damaged.

[0064] An oxygen content detection device 206 is installed on the side wall 205 of the forming chamber. When the oxygen content in the forming chamber 2 is higher than the set value, the equipment will stop working and trigger an alarm until the oxygen content drops below the set value. A second operation door 246 is opened in front of the side wall 205 of the forming chamber to facilitate the replacement of the cutting edge 230.

[0065] As Figure 5As shown in the figure, the powder storage bin 129 is docked with the powder collection interface 223 of the scraper 212 through the powder dropping pipe 218. The upper end of the powder dropping pipe 218 is connected to the powder storage bin 129, and the lower end is connected to the scraper 212 through the powder collection interface 223 at the top of the scraper 212 to realize the transportation of metal powder. The powder feeding adopts a screw conveying form. A screw blade conveying shaft 220 is installed inside the powder dropping pipe 218. The screw blade conveying shaft 220 can realize the quantitative transportation of metal powder. A magnetic levitation drive motor 221 is installed at the upper end of the powder dropping pipe 218. A coil 222 is arranged at the upper end of the screw blade conveying shaft 220. The magnetic levitation drive motor 221 drives the coil 222 to rotate, driving the screw blade conveying shaft 220 to rotate, so as to realize the function of transporting metal powder.

[0066] As Figure 6 shown, a powder collection interface 223 is opened at the top end of the scraper 212. The powder collection interface 223 is communicated with the bottom of the powder dropping pipe 218. The inside of the scraper 212 includes an upper chamber and a lower powder dropping bin 232. The metal powder is transported to the upper chamber through the powder dropping pipe 218. There is a powder dropping hole 231 at the quarter point of the scraper length in the upper chamber. The periphery of the powder dropping hole 231 is concave downward, which is conducive to transporting the metal powder in the upper chamber to the powder dropping hole 231; a motor installation bin 233 is also opened on one side of the powder dropping bin 232. A powder spreading motor 225 is fixed in the motor installation bin 233. A screw conveying shaft 227 is arranged inside the powder dropping bin 232. The right end of the screw conveying shaft 227 passes through the side wall of the powder dropping bin 232 and enters the motor installation bin 233, and is connected to the output shaft of the powder spreading motor 225 through a third coupling 226. The left end of the screw conveying shaft 227 is connected to a second bearing 228. The second bearing 228 is installed in a second bearing seat 229 on the side wall of the powder dropping bin 232. A blade 230 is installed at the bottom of the powder dropping bin 232. Powder dropping ports are respectively opened on both sides of the blade 230 at the bottom of the powder dropping bin 232. The metal powder entering the powder dropping bin 232 from the powder dropping hole 231 is transported to the powder dropping ports on both sides of the blade 230 through the screw conveying shaft 227. As the scraper 212 moves, the blade 230 is driven to move, and the metal powder is laid on the surface of the forming substrate 203.

[0067] As Figure 7 and Figure 8As shown, a forming cavity 234 is provided on the lower surface of the forming platform 202. The lower surface of the forming substrate 203 is connected to one end of the forming base body 247. The forming base body 247 is located in the forming cavity 234, and the other end of the forming base body 247 passes through the forming cavity 234 and is connected to the first driving assembly. The first driving assembly is used to drive the forming base body 247 and drive the forming substrate 203 to move up and down relative to the forming opening. When the forming substrate 203 moves downward, it enters the forming cavity 234. The forming cavity 234 is designed to be suitable for containing the liquid 242. A liquid inlet 235 and a liquid outlet 236 are provided on the forming cavity 234. During operation, the liquid 242 enters the forming cavity 234 through the liquid inlet 235. After the operation is completed, the liquid 242 is discharged from the forming cavity 234 through the liquid outlet 236. A filter screen 237 is installed at the liquid outlet 236. A heating device 241 is installed in the forming cavity 234 to heat the liquid 242 according to the set temperature. It should be noted that the contact between the forming base body 247 and the forming cavity 234 is sealed to prevent liquid leakage.

[0068] A liquid level adjusting assembly is communicated with the outside of the forming cavity 234. The liquid level adjusting assembly is used to adjust the liquid level height in the forming cavity 234. The liquid level adjusting assembly includes a liquid level adjusting chamber 238. The left bottom of the forming cavity 234 is connected to the liquid level adjusting chamber 238. A liquid level adjusting motor 239 is installed at one end of the liquid level adjusting chamber 238 away from the forming cavity 234. A baffle 240 is installed in the liquid level adjusting chamber 238. The liquid level adjusting motor 239 is used to drive the baffle 240 to approach or move away from the forming cavity 234, adjust the content of the liquid 242 in the forming cavity 234, and further adjust the liquid level height in the forming cavity 234. Specifically, as Figure 7 shown, the liquid level adjusting chamber 238 is arranged in an L-shaped structure. The liquid level adjusting motor 239 is installed on the top of the liquid level adjusting chamber 238. The bottom of the liquid level adjusting motor 239 is provided with a baffle 240. The baffle 240 abuts against the side wall of the liquid level adjusting chamber 238. The liquid level adjusting motor 239 can drive the baffle 240 to move up and down. When the baffle 240 moves downward, the liquid 242 is pressed from the liquid level adjusting chamber 238 into the forming cavity 234, and the liquid level in the forming cavity 234 rises. When the baffle 240 moves upward, the liquid 242 enters the liquid level adjusting chamber 238 from the forming cavity 234, and the liquid level in the forming cavity 234 drops.

[0069] As Figure 8 shown, Figure 8The 243 in it represents the metal powder layer. The density of the metal powder is less than that of the liquid 242. The metal powder floats on the surface of the liquid 242 under the action of buoyancy and forms the metal powder layer 243. The metal powder layer 243 includes a wet layer 244 and a dry layer 245. The wet layer 244 is immersed in the liquid 242, and the dry layer 245 is above the wet layer 244. The thickness of the metal powder layer 243 is 0.1 mm to 100 mm. The types of the liquid 242 include, but are not limited to, low melting point alloy materials such as tin-based alloys, bismuth-based alloys, zinc-based alloys, indium-based alloys, and non-metallic materials such as phenolic resins, acrylates, and asphalt. It is required that the material constituting the liquid 242 does not interfere with the normal forming of the metal powder.

[0070] During the printing process, the liquid level of the liquid 242 is controlled to remain unchanged. The forming substrate 203 moves downward relative to the forming orifice. As the blade 212 moves, the cutting edge 230 is driven to move, and the metal powder is laid on the liquid surface. The laser melts the metal powder on the liquid surface.

[0071] As Figure 9 shown, the forming cavity 234 is located in the machine tool base 3. The lower end of the forming matrix 247 passes through the bottom of the forming cavity 234 and is located outside the forming cavity 234. Two Z-axis movement guide rails 306 are arranged side by side on the side wall 304 of the machine tool base. The lower end of the forming matrix 247 is installed on the two Z-axis movement guide rails 306 and can move up and down in the vertical direction along the two Z-axis movement guide rails 306. The first driving component includes a collar 308, a first lead screw 309, and a servo motor 311. A cavity is formed inside the forming matrix 247. The lower end of the forming matrix 247 forms a first ball screw motion pair with the first lead screw 309 through the collar 308. The upper end of the first lead screw 309 is located in the cavity inside the forming matrix 247. A second motor base 312 is installed on the bottom plate 305 of the machine tool base 3. The second motor base 312 is equipped with a servo motor 311. The servo motor 311 is connected to the first lead screw 309 through a first coupling 310. The servo motor 311 drives the forming matrix 247 to move along the Z-axis movement guide rail 306 through the first ball screw motion pair, so that the forming substrate 203 can move up and down relative to the forming orifice. It should be noted that during the downward movement, the upper end of the first lead screw 309 is located in the cavity inside the forming matrix 247.

[0072] As Figure 9 and Figure 4 shown, a powder collecting hole 204 is provided on the forming platform 202. A powder collecting funnel 301 is installed at the bottom of the powder collecting hole 204. During the powder laying process, the excess metal powder on the liquid surface falls from the powder collecting hole 204, converges through the powder collecting funnel 301, and then falls into the powder recovery box 303 through the powder collecting pipe 302. As Figure 1 shown, a third operation door 313 is opened in front of the machine tool base 3, which is convenient for cleaning the powder recovery box 303 in time.

[0073] During operation, the forming substrate 247 first moves along the Z-axis movement guide 306 to make the surface of the forming substrate 203 flush with the forming platform 202. Liquid 242 is added into the forming cavity 234 from the liquid inlet 235. The baffle 240 is driven by the liquid level adjustment motor 239 in the liquid level adjustment chamber 238 to move up and down to adjust the liquid level, making the liquid level flush with the forming substrate 203. The liquid is heated to a suitable processing temperature by the heating device 241.

[0074] When spreading powder, the doctor blade 212 moves to the right limit switch 215. The magnetic levitation drive motor 221 drives the coil 222 to drive the spiral blade conveying shaft 220 to rotate a specified angle, so that the metal powder falls from the powder dropping tube 218 into the powder receiving interface 223. At this time, the position of the powder storage bin 129 shown in Figure 2 corresponds to the powder dropping tube 218. After the metal powder enters the doctor blade 212, it falls into the powder dropping bin 232 through the powder dropping hole 231 inside the doctor blade 212. The powder spreading motor 225 drives the spiral conveying shaft 227 to rotate, and the metal powder falls from the powder dropping port along the direction of the blade edge 230 onto the liquid surface of the liquid 242. The X-direction movement motor 207 drives the second lead screw 210 to rotate. Through the cooperation of the lead screw nut 224 and the second lead screw 210, the doctor blade 212 is driven to move along the X-direction movement guide 211 to the left limit switch 216, spreading the metal powder evenly on the liquid surface and pushing the excess metal powder into the powder receiving hole 204.

[0075] After the powder spreading is completed, the laser melts the metal powder in the specified area under the deflection of the galvanometer scanner 120. After melting the powder in all areas of this layer, the forming substrate 203 descends a certain height, and the liquid level of the liquid 242 is adjusted to remain stationary, waiting for the next layer of powder spreading. Since the unprinted metal powder on the liquid surface of the liquid 242 does not need to descend, when spreading the powder for the next layer, only the metal powder in the printing area needs to be replenished, thus reducing the consumption of metal powder.

[0076] After the printing is completed, the doctor blade 212 first returns to the right limit switch 215 to standby. The liquid outlet 236 is opened to discharge the liquid 242 from the forming cavity 234. The forming substrate 203 rises, the second operation door 246 is opened, and the printed part is taken out and the powder in the forming cavity 234 is cleaned. Then the third operation door 313 is opened to clean the metal powder in the powder recovery box 303.

[0077] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and its equivalent technologies, these modifications and variations are also intended to be included therein.

Claims

1. A liquid-supported dot matrix laser area printing additive manufacturing device, characterized in that Including: An optical chamber (1) in which an optical component is installed. The optical component is used to combine, homogenize, and pattern multiple laser beams and convey them into a forming chamber (2); A forming platform (202) is arranged in the forming chamber (2). A forming opening is formed on the forming platform (202). A forming substrate (203) is installed at the forming opening. The forming substrate (203) can move up and down relative to the forming opening. A forming cavity (234) is arranged on the lower surface of the forming platform (202). When the forming substrate (203) moves downward, it enters the forming cavity (234). One end of a forming matrix (247) is fixedly connected to the lower surface of the forming substrate (203), and the other end of the forming matrix (247) passes through the forming cavity (234) and is connected to a first driving component. The first driving component is used to drive the forming matrix (247) and drive the forming substrate (203) to move up and down relative to the forming opening; A powder spreading component is installed in the forming chamber (2). A liquid level adjusting component is communicated with the outside of the forming cavity (234). During printing, a liquid (242) is contained in the forming cavity (234), and the liquid level of the liquid (242) is flush with the surface of the forming substrate (203) at the initial stage of printing. During the printing process, the forming substrate (203) moves downward relative to the forming opening, and the liquid level adjusting component keeps the liquid level of the liquid (242) unchanged. The powder spreading component spreads metal powder onto the liquid surface. The density of the metal powder is less than that of the liquid (242). The laser output by the optical component melts the metal powder on the liquid surface.

2. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 1, wherein The metal powder floats on the surface of the liquid (242) and forms a wet layer (244) and a dry layer (245). The wet layer (244) is immersed in the liquid (242), and the dry layer (245) is above the wet layer (244).

3. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 1, wherein A liquid inlet (235) and a liquid outlet (236) are arranged on the forming cavity (234). A filter screen (237) is installed at the liquid outlet (236). A heating device (241) is installed in the forming cavity (234). The liquid level adjusting component includes a liquid level adjusting chamber (238). The bottom of the forming cavity (234) is communicated with the liquid level adjusting chamber (238). A liquid level adjusting motor (239) is installed at one end of the liquid level adjusting chamber (238) away from the forming cavity (234). A baffle (240) is installed in the liquid level adjusting chamber (238). The liquid level adjusting motor (239) is used to drive the baffle (240) to approach or move away from the forming cavity (234), thereby adjusting the liquid level height in the forming cavity (234).

4. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 1, characterized in that The optical component includes an array laser (102), an entrance focusing lens (105), a first lens (106), a second lens (107), a microlens array (108), a third lens (109), a fourth lens (110), a one-way reflecting mirror (111), an addressable light valve (112), a signal laser (113), a polarization reflecting mirror (114), a fifth lens (115), a sixth lens (116), an exit focusing lens (117), and a galvanometer (120); The array laser (102) is used to emit laser light. A first optical fiber interface (103) is provided on the array laser (102). The emitted laser light converges into a large-diameter laser in the first optical fiber interface (103) and is conducted through the first optical fiber (104) into the entrance focusing mirror (105). The entrance focusing mirror (105) is used to collimate the laser light. The laser light emitted from the entrance focusing mirror (105) passes through the focal point of the first lens (106) and enters the first lens (106) perpendicularly to its surface. The first lens (106) and the second lens (107) are placed opposite to each other, and the focal points of both the first lens (106) and the second lens (107) are on the laser propagation path. The microlens array (108) is placed perpendicular to the laser path and is used to homogenize the laser intensity. After the laser light vertically exits from the microlens array (108), it enters the third lens (109) and the fourth lens (110) through the focal points of the third lens (109) and the fourth lens (110). The one-way mirror (111) is placed on the laser propagation path, and the incident angle of the laser with the one-way mirror (111) is 45°. After passing through the one-way mirror (111), the laser is vertically incident on one side surface of the addressable light valve (112). The signal laser (113) is placed on the other side of the addressable light valve (112). A low-frequency laser with a specific shape is emitted from the signal laser (113) and is vertically incident on the other side surface of the addressable light valve (112). The addressable light valve (112) receives the low-frequency laser from the signal laser (113) and locally polarizes the reflected laser when reflecting the laser passing through the one-way mirror (111) on one side. The laser is reflected from one side surface of the addressable light valve (112), is incident on the other side of the one-way mirror (111) at an angle of 45° with the surface of the one-way mirror (111) and is reflected. The reflected laser is incident on the surface of the polarization reflecting mirror (114) at an angle of 45°. At this time, the laser polarized when reflected by the addressable light valve (112) is reflected by the polarization reflecting mirror (114), and the non-polarized laser penetrates the polarization reflecting mirror (114). The polarized laser is reflected by the polarization reflecting mirror (114) and then vertically enters the fifth lens (115), the sixth lens (116) and the exit focusing mirror (117). After passing through the exit focusing mirror (117), the laser is input into the galvanometer (120), and finally the laser is deflected by the galvanometer (120) and hits the metal powder to be melted.

5. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 4, wherein The optical assembly further includes a total reflection mirror (122), a recycling adjustment mirror (123) and a laser recycler (126). After passing through the polarization reflecting mirror (114), the non-polarized laser is incident on the surface of the total reflection mirror (122) at an angle of 45°, is reflected by the total reflection mirror (122) and vertically enters the recycling adjustment mirror (123). The laser is input into the laser recycler (126) through the third optical fiber interface (124) and the third optical fiber (125).

6. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 1, characterized in that, The part of the forming substrate (247) located outside the forming cavity (234) is movably installed on the Z-axis motion guide rail (306) and can move up and down along the Z-axis motion guide rail (306) under the driving action of the first driving component. The first driving component includes a collar (308), a first lead screw (309) and a servo motor (311). The other end of the forming substrate (247) forms a first ball screw motion pair with the first lead screw (309) through the collar (308). The servo motor (311) is connected to the first lead screw (309) through the first coupling (310). The servo motor (311) drives the forming substrate (247) to move along the Z-axis motion guide rail (306) through the first ball screw motion pair.

7. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 1, wherein The powder spreading component includes a doctor blade (212). The doctor blade (212) is located above the forming platform (202). X-axis motion guide rails (211) are respectively installed on both sides of the forming platform (202). The doctor blade (212) moves along the X-axis motion guide rail (211) under the driving action of the second driving component; A powder storage bin (129) is installed in the optical chamber (1). The top of the doctor blade (212) is communicated with the powder storage bin (129) through a powder dropping pipe (218); The inside of the doctor blade (212) includes an upper chamber and a lower powder dropping bin (232). The upper chamber is equally divided in the length direction of the doctor blade with a plurality of powder dropping holes (231). Metal powder enters the powder dropping bin (232) through the plurality of powder dropping holes (231). A blade edge (230) is installed at the bottom of the powder dropping bin (232). Powder dropping ports are respectively opened on both sides of the blade edge (230) at the bottom of the powder dropping bin (232). The metal powder in the powder dropping bin (232) drops onto the liquid surface through the powder dropping ports and is evenly laid on the liquid surface during the movement of the blade edge (230); A powder collecting hole (204) is provided on the forming platform (202). A powder collecting funnel (301) is installed below the powder collecting hole (204). During the powder spreading process, the excess metal powder on the liquid surface drops from the powder collecting hole (204), converges through the powder collecting funnel (301) and then falls into the powder recovery box (303) through the powder collecting pipe (302).

8. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 7, wherein A spiral blade conveying shaft (220) is installed inside the powder dropping pipe (218). A coil (222) is arranged at the upper end of the spiral blade conveying shaft (220). A magnetic levitation driving motor (221) is installed at the upper end of the powder dropping pipe (218). The magnetic levitation driving motor (221) drives the coil (222) to rotate and drives the spiral blade conveying shaft (220) to rotate, quantitatively conveying the metal powder from the powder storage bin (129) to the upper chamber inside the doctor blade (212); A powder spreading motor (225) is installed on one side of the powder dropping bin (232) inside the doctor blade (212). A spiral conveying shaft (227) is arranged inside the powder dropping bin (232). One end of the spiral conveying shaft (227) is connected to the output shaft of the powder spreading motor (225), and the other end is rotatably connected to the side wall of the powder dropping bin (232).

9. The liquid-supported dot matrix laser area printing additive manufacturing equipment according to claim 7, wherein, The second driving component includes a lead screw nut (224), a second lead screw (210), and an X-direction movement motor (207). Lead screw nuts (224) are respectively fixed to both ends of the scraper (212). Each lead screw nut (224) is engaged with a second lead screw (210) to form a second ball screw pair. One end of the second lead screw (210) is connected to the X-direction movement motor (207) through a second coupling (209). The X-direction movement motor (207) drives the scraper (212) to move back and forth along the X-direction movement guide rail (211) through the second ball screw pair.

10. A method for additive manufacturing of liquid-supported dot matrix laser area printing, characterized in that, It is carried out by using the liquid-supported dot matrix laser area printing additive manufacturing equipment described in claim 1, including the following steps: When starting to work, the forming substrate (247) is driven to move by the first driving component to make the forming substrate (203) flush with the surface of the forming platform (202). Liquid (242) is added into the forming cavity (234), and the liquid level is made flush with the surface of the forming substrate (203). Through the powder spreading component, metal powder is evenly spread on the liquid surface of the liquid (242). After powder spreading is completed, the laser output by the optical component melts the metal powder on the liquid surface. After melting the metal powder in all areas of this layer, the forming substrate (203) is driven to descend by a certain height by the first driving component, and the liquid level adjusting component is used to keep the liquid level unchanged, waiting for powder spreading in the next layer. Then, the newly spread metal powder is melted, and the steps of descending the forming substrate (203), powder spreading, and melting are repeated in a cycle until the printing of the part is completed. After printing is completed, the liquid (242) is discharged from the forming cavity (234), the forming substrate (203) rises above the forming platform (202), and the printed part is taken out and the metal powder in the forming cavity (234) is cleaned.

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