CN220031192U

CN220031192U - A three-dimensional inkjet printer that is used for three-dimensional printing strickle device and has it

Info

Publication number: CN220031192U
Application number: CN202223605617.5U
Authority: CN
Inventors: 梁福鹏; 赵海鹏; 蔡艳
Original assignee: Nanjing Taitao Intelligent System Co ltd
Current assignee: Nanjing Taitao Intelligent System Co ltd
Priority date: 2022-02-26
Filing date: 2022-12-31
Publication date: 2023-11-17
Anticipated expiration: 2032-12-31
Also published as: CN116080069A

Abstract

The invention relates to a strickling device for three-dimensional printing and a three-dimensional printer with the strickling device, which are used for strickling an area which is not completely solidified on the surface of a workpiece in the three-dimensional printing process, and belong to the technical field of additive manufacturing. A contact part is arranged for contacting with the area of the workpiece which is not completely solidified in the three-dimensional printing process, and the contact part is provided with a channel for the printing raw material to pass through; in the process of carrying out morphology regulation and control on the area of the workpiece which is not completely solidified by the contact component, the surface of the outlet end of the channel is not parallel to the current molding surface of the workpiece, namely an acute angle is formed between the surface of the outlet end of the channel and the current molding surface of the workpiece, and the direction of the opening of the included angle can be changed along with the change of the deposition direction of the printing raw material on the surface of the workpiece, so that the contact component can move relative to the workpiece in the direction which is not parallel to the current molding surface of the workpiece. The invention supports real-time leveling and in-situ micro-mechanical forging in the high-speed three-dimensional printing process, can reduce the stress of a workpiece, and has small vibration.

Description

A three-dimensional inkjet printer that is used for three-dimensional printing strickle device and has it

Technical Field

The invention relates to a device for scraping an area of a workpiece surface which is not completely solidified in a three-dimensional printing process, in particular to a three-dimensional printer with the device, and belongs to the technical field of additive manufacturing.

Background

Three-dimensional printing technology originated in the united states at the earliest. Currently, the mainstream three-dimensional printing techniques, such as stereolithography (Stereo Lithography Apparatus, SLA), fused deposition fabrication (Fused Deposition Modeling, FDM), selective laser sintering (Selecting Laser Sintering, SLS), three-dimensional powder bonding (Three Dimensional Printing and Gluing,3 DP), have been commercialized in the united states and europe in the eighth nineties of the 20 th century. In metal three-dimensional printing techniques using metal as the printing material, selective laser melting (Selective Laser Melting, SLM), laser near forming (Laser Engineered Net Shaping, LENS), electron beam melting (Electron Beam Melting, EBM), wire arc melting (Wire and Arc Additive Manufacture, WAAM) are all required to melt solid metal material in a three-dimensional forming process, and at the same time, to heat and melt the region of the print body where the molten metal material is being deposited (the print body is formed by cooling the molten material after deposition, the print body is also referred to as a workpiece) so as to bond the print body and the molten material together in a metallurgical fusion manner. FDM plastic three-dimensional printing is a low cost technology, and desktop FDM printers are the most widely used plastic three-dimensional printers; after the plastic raw material is heated and melted by the printing head of the FDM printer, the melted plastic is output to a forming table through a hard extrusion head (such as a raw material output head with an output hole, which is made of brass, stainless steel and the like); after flowing out from the hole at the front end of the hard extrusion head, the molten plastic is smoothed by the front end face of the hard extrusion head; thus, the upper plane of the part printed by the desktop FDM plastic three-dimensional printer is generally flat and smooth. The melting point of plastics is generally lower (the melting point of most plastic raw materials for three-dimensional printing is lower than 200 ℃), and the hardness of common plastics is far lower than that of brass and stainless steel, and the problem that the molten plastics obviously erode the brass and the stainless steel does not exist, so that a printing head of an FDM plastic three-dimensional printer can reliably work for a long time by using a metal extrusion head without worrying about the problems of erosion, oxidization, abrasion and the like of the extrusion head. For the FDM plastic three-dimensional printing technology, reference may be made to chinese patent application nos. 201621370582.3 and 201621251883.4. However, the environment faced by the three-dimensional printing of metals is very different from that of plastics, for example, the direct energy deposition technology (Directed Energy Deposition, DED) is that solid metal raw materials are deposited on a molten pool of a printing body after being heated and melted (the existing coaxial wire feeding and paraxial wire feeding three-dimensional printing technology based on laser heating, the paraxial wire feeding three-dimensional printing technology based on arc heating, the coaxial powder feeding and paraxial powder feeding three-dimensional printing technology based on laser heating, the paraxial wire feeding three-dimensional printing technology based on electron beam heating and the like belong to the technology of the class of DED) and the environment with the temperature far higher than the printing working temperature of FDM is faced. If the printing head imitates the FDM plastic three-dimensional printing, the mode of extruding the molten metal through the extrusion head is also used for three-dimensional printing of metals, especially the three-dimensional printing of high-melting point metals, such as printing stainless steel, even if the extrusion head is made of common ultra-high-melting point metals (such as tungsten), the extrusion head can be rapidly damaged due to the occurrence of melting under the condition of inert gas protection (such as the rapid increase of the caliber of an output hole of the extrusion head); if the extrusion head is made of a high-temperature ceramic material, although the melting point of the high-temperature ceramic may be higher than that of the molten metal (e.g., high-purity alumina ceramic, magnesia ceramic), the mechanical strength of the ceramic is low (e.g., cracking is easy, and wear resistance is lowered) and the ceramic is extremely fragile under a high-temperature environment (e.g., 1400 ℃ or higher), and the ceramic cannot be used as a material of the extrusion head. If the extrusion head is cooled (e.g., water-cooled) to protect the extrusion head, the extrusion head may reduce the temperature of the molten metal passing through its internal output orifice, which may cause the output orifice of the extrusion head to clog, thereby failing to print. Also, the molten metal feedstock needs to be deposited on the bath to achieve metallurgical fusion, and if the molten metal feedstock is applied to the print body using an extrusion head, the volume of the front end of the extrusion head may prevent the propagation of heating energy required to heat the print body to produce the bath, e.g., arcing, electron beam, laser beam, may be blocked by the front end of the extrusion head. Thus, although there are numerous patent applications and papers on three-dimensional printing of metals to date that imitate the way in which molten raw materials are extruded from printheads of FDM plastic three-dimensional printers, such as chinese patent application with application publication No. CN104338933a (application No. 201410513433.7), no commercially available technology of this type has emerged, particularly technology that can print metallic materials such as stainless steel, titanium, and the like. The printing head is provided with a micro-melting furnace, the solid metal raw material is melted by the micro-melting furnace, and then molten metal liquid drops are sprayed onto a printing platform or a printing body through nozzles, but the nozzles do not 'trowelling' the deposited molten metal or the metal which is not solidified, and the damage of mechanical action generated by the 'trowelling' action to the nozzles is not considered, so that the nozzles can be made of quartz and high-temperature ceramic materials, the molten liquid drops of lower-melting-point metal materials such as aluminum are sprayed, and the nozzles can work for a long time, for example, the technical scheme disclosed in U.S. patent publication No. 2015/0273577A1 (application No. 14/228,681) can be used for example. In the current common metal three-dimensional printing technology, as long as metal needs to be melted in the three-dimensional printing process, the technology is not based on a powder bed mode (such as SLM), but all the technology has the problem that the surface morphology of the molten metal raw material after deposition is poor, especially the technology of the general class DED: after the metal liquid drops are deposited, the surface can show an uneven appearance, and especially if the metal liquid drops splash in the deposition process, the uneven appearance can be more obvious; in addition to the local irregularities, a striped trench structure may also occur. Surface topography defects are particularly prominent in wire arc fusion forming (Wire and Arc Additive Manufacture, WAAM) techniques. Defects in the surface topography can be transferred and accumulated layer by layer, and even magnified layer by layer, potentially resulting in unusable parts that are ultimately printed, or potentially leading to print failure. There are also add-drop techniques that integrate DED technology with machining, by using conventional mechanical cutting methods to trim the surface topography of the printed body layer by layer during three-dimensional printing, or in situ after printing is completed. If the surface topography of the molten feedstock can be quickly tailored after it is deposited, the print quality of the DED technology will be greatly improved.

In the existing metal three-dimensional printing technology, the material performance of metal materials, especially alloy materials, after three-dimensional forming often cannot reach the performance of forged alloy materials in the traditional metal material processing technology, so various auxiliary technologies are presented for regulating and controlling the metal materials in the three-dimensional forming process to obtain forging or forging-like performances, for example, chinese patent application No. 201010147632.2, chinese patent application No. 201610183468.8, chinese patent application No. "method for non-contact additive MANUFACTURING of SOLIDIFICATION structures of metal parts and Chinese patent application No. 15 for magnetic control metal 3D printing device", and PCT International patent application publication No. WO2019002563A2, and PCT International patent application No. REFINEMENT AND GENERAL PHASE TRANSFORMATION CONTROL THROUGH APPLICATION OF IN SITU GAS JET IMPINGEMENT IN METAL ADDITIVE MANUFACTURING. The material regulation and control method for the three-dimensional printed part, besides regulating and controlling the metal material in the three-dimensional forming process, also can regulate and control the part after the three-dimensional printing is finished, for example: the printed part is integrally hot isostatic pressed (Hot Isostatic Pressing) to fuse particles of insufficiently fused material (e.g., entrapped but insufficiently melted metal powder produced by SLM technology during the forming process) with adjacent material and to eliminate defects such as hot cracks, micro-holes, residual stresses, etc. inside the part. For the DED technology, if the surface morphology of the molten raw material can be rapidly modified by a strickling mode after the molten raw material is deposited, the molten metal can be extruded by mechanical strickling, the growth of metal grains is destroyed, fine grains are obtained, the density is improved, the stress is reduced, the mechanical property of the part printed by the DED technology is improved, and the forging grade property is obtained.

Disclosure of Invention

The invention aims to provide a device capable of scraping an area which is not completely solidified on the surface of a workpiece in a three-dimensional printing process, and capable of synchronously scraping the surface of the workpiece which is not solidified after deposition in a three-dimensional printing forming process.

The second object of the present invention is to provide a screeding device capable of performing press forging on a region of a work surface which has not yet been completely solidified in a three-dimensional printing forming process.

The third object of the present invention is to provide a three-dimensional printer having the above-mentioned scraping device.

In order to achieve the above object, according to one aspect of the present invention, the technical solution adopted by the present invention is:

a screeding device for three-dimensional printing is provided with a contact member for making contact with an area of a workpiece which has not yet been completely solidified during three-dimensional printing; the contact part is contacted with the area of the workpiece which is not completely solidified, so that the morphology of the area of the workpiece which is not completely solidified is regulated and controlled; the workpiece (namely a printing body) is an object formed by depositing printing raw materials in the three-dimensional printing process; ( Explanation: the fused printing raw material is converted into a part of a workpiece after the deposition is finished, the raw material which is finished but is in a fused state and a softened state and a region of the workpiece which is heated, remelted and softened by heating energy belong to a 'region of the workpiece which is not completely solidified', before the raw material which is finished on the surface of the workpiece is completely solidified, the contact part can be contacted with the raw material which is finished and is not completely solidified, or can be contacted with the raw material which is finished and is not completely solidified and other regions of the workpiece at the same time, and the surface morphology of the raw material which is finished and deposited is trimmed, namely, the surface morphology of the raw material which is finished and deposited is scraped off by mechanical force; )

The method is characterized in that:

the contact part is provided with a channel (such as a round hole) for printing raw materials to pass through, and the channel is provided with an inlet end and an outlet end; in the three-dimensional printing process, printing raw materials enter the channel from the inlet end and leave the channel from the outlet end, one side of the contact part, which is close to the workpiece, is provided with a contact area which surrounds the outside of the outlet end of the channel, and the contact area is in contact with an area of the workpiece which is not completely solidified;

in the process of performing morphology regulation and control on the area of the workpiece which is not completely solidified by the contact component, the surface of the outlet end of the channel is not parallel to the current molding surface of the workpiece, namely an acute angle is formed between the surface of the outlet end of the channel and the current molding surface of the workpiece, and the direction of the angle opening can be changed along with the change of the deposition direction of the printing raw material on the surface of the workpiece, so that the contact component can move relative to the workpiece in the direction which is not parallel to the current molding surface of the workpiece;

the current forming surface of the workpiece surface is the surface based on the current forming area of the current forming layer in the three-dimensional printing layer-by-layer forming process.

Optionally:

the contact area is a plane or a curved surface.

( Explanation: when the contact area is a plane, the surface of the outlet end of the channel is coplanar with the surface of the contact area; when the contact area is a curved surface, the surface of the outlet end of the channel is tangent to the curved surface of the contact area. )

Optionally:

the included angle is variable (for example, the amplitude and frequency of the angle change are adjustable and controlled).

Optionally:

the included angle is formed by a plurality of openings, and the openings of the included angle face the advancing direction of a deposition path of the printing raw material when the printing raw material is deposited on the surface of the workpiece. (during three-dimensional printing, the direction of the deposition path of the printing stock is constantly changing, and the orientation of the included angle is also changed.):

the opening direction of the included angle is completely overlapped or not completely overlapped with the advancing direction of a deposition path of the printing raw material when the printing raw material is deposited on the surface of the workpiece.

Optionally:

in the three-dimensional printing process, when the molten printing raw material is adopted, the molten printing raw material is not contacted with the inner wall of the channel of the contact part in the process of passing through the channel.

Optionally:

the contact member may be rotatable or the contact member may be rotatable and movable. ( For example: the contact part is connected with the connecting bracket through a spherical bearing, and the contact part performs spherical rotation by taking the rotation spherical center of the spherical bearing as the rotation center; another example is: the contact member moves in a direction perpendicular to the current molding surface of the workpiece together with the member connected thereto. )

Optionally:

the printing head of the three-dimensional printer is characterized by further comprising a connecting bracket connected with the printing head of the three-dimensional printer, wherein the contact part can rotate relative to the connecting bracket, or the contact part can rotate and move relative to the connecting bracket.

Optionally:

a driving device for driving the contact part to rotate or a driving device for driving the contact part to rotate and move is arranged; ( Explanation: the driving device directly applies an acting force to the contact part or indirectly drives the contact part by applying an acting force to a part connected with the contact part; )

The driving device adopts one or a combination of a plurality of driving modes of magnetic force driving, mechanical elastic driving, fluid driving, thermal deformation driving, magnetic deformation driving, electric deformation driving and mechanical screw driving; wherein the magnetic force drives the power of the magnetic force. ( For example: the electromagnet drive and the motor drive both belong to magnetic drive; spring elastic force drive belongs to mechanical elastic force drive; both hydraulic and pneumatic drives are fluid drives; the drive generated by the deformation of the thermally deformable material belongs to the thermally deformable drive; the drive generated by the deformation of the magnetic deformation material belongs to the magnetic deformation drive; the drive generated by deformation of the electro-deformation material belongs to electro-deformation drive, and the piezoelectric ceramic belongs to the electro-deformation material; the mechanical screw drive is achieved by rotating the screw to push the components connected to the nut to move. )

Optionally:

the driving device controls the orientation of the included angle opening, so that the orientation of the included angle opening is changed along with the change of the deposition direction of the printing raw material on the surface of the workpiece, or the orientation of the included angle opening is not changed along with the change of the deposition direction of the printing raw material on the surface of the workpiece.

Optionally:

the driving device generates acting force directed to the workpiece on the contact component.

Optionally:

setting a limit structure for limiting the rotation range and/or the movement range of the contact part; ( Explanation: the limiting structure can limit the contact part by applying acting force to the contact part or limit the part connected with the contact part, so that the limitation of the contact part is realized; )

The movement includes such movement: during the three-dimensional printing process, the contact component is far away from or near to the current forming surface of the workpiece surface.

Optionally:

the support body is used for installing the contact part, and the contact part is connected with the connecting bracket in a relatively rotatable and relatively movable manner through the support body;

the support body and the connecting bracket can move relatively;

The bearing comprises a spherical bearing stator (namely an inactive part of the spherical bearing) arranged on the support body and a spherical bearing rotor (namely an active part of the spherical bearing) arranged on the contact part, wherein the rotation of the contact part relative to the support body is guided by the spherical bearing. ( For example: spherical joint bearings are used; the spherical joint bearing is a spherical sliding bearing, and the sliding contact surface is an inner spherical surface and an outer spherical surface. )

Optionally:

the limiting structure is provided with a spherical cambered surface for restraining the spherical bearing rotor, and the center of the spherical cambered surface is concentric with the rotation center of the spherical bearing.

Optionally:

a liquid cooling and/or air cooling structure is arranged to cool the contact part; ( For example: the heat of the contact part is conducted away through the connection of the part with the water cooling passage/cooling cavity channel inside and the contact part; another example is: the heat dissipation fins are arranged on the parts connected with the contact parts, and high-speed airflow flows through the heat dissipation fins and conducts heat of the contact parts away; )

Optionally:

a lubricant or a heat conduction agent with high heat conductivity is arranged on a direct contact surface or an indirect contact surface between the contact part and the connecting bracket; ( For example: the contact surface between the spherical bearing stator arranged on the support body and the spherical bearing rotor arranged on the contact part is provided with a thin layer of lubricant with high heat conductivity coefficient; )

The whole contact part is a rotating body or the contact area of the contact part, which is used for contacting with the not-yet-completely-solidified area of the workpiece, is the rotating body.

Optionally:

a passage is provided for generating an air flow not perpendicular to the current forming surface of the workpiece, the air flow flowing at least at the inlet end or at the outlet end of the passage of the contact member; the air flow is generated by means of spraying and/or suction. (e.g., creating a lateral air flow at the inlet end of the passage of the contact member; the concept opposite the lateral direction is longitudinal, longitudinal perpendicular to the current forming surface of the workpiece; the lateral air flow is used to blow away or suck away printing material debris that may be generated during three-dimensional printing.) optionally:

the contact part is detachable. ( For example: the contact member is cylindrical and has a catching groove, and the contact member is mounted in a circular mounting hole of a member connected thereto and is caught by the catching groove. )

Optionally:

the contact member is not detachable. ( For example: the contact part and the support body are integrally formed, or are connected into a whole in a welding mode or are connected into a whole in an interference fit mode. )

Optionally:

A sensor is provided for detecting the position and/or the movement state of the contact member and/or the member connected to the contact member. ( For example: at least three laser ranging sensors are arranged above the contact part, the laser ranging sensors are immovable, the laser ranging sensors acquire the distance between the contact part or other parts connected with the contact part relative to the laser ranging sensors in real time, and the control software can calculate the current position, inclination angle and other state information of the contact part according to the data of the laser ranging sensors. )

Optionally:

the control circuit is connected with the driving device and controls the position state of the contact part through the driving device; or, a control circuit, a sensor and a driving device are arranged, the control circuit is connected with the sensor and the driving device, and the control circuit controls the position state of the contact part through the driving device according to the detection signal of the sensor; ( Explanation: in the three-dimensional printing process, the distance between the contact part and the current forming surface of the workpiece surface, the size of an included angle between the contact part and the current forming surface of the workpiece surface, the direction of an included angle opening and the like are all in a position state. )

Optionally:

the contact area is detachable or the contact area and other areas of the contact part are connected into a whole and are not detachable, and the spherical bearing is used as an intermediary for connecting the contact part with a printing head of the three-dimensional printer; the spherical bearing is hollow, and the printing raw material passes through the hollow area of the spherical bearing and then passes through the channel of the contact part and reaches the surface of the workpiece in the three-dimensional printing process; a permanent magnet is arranged and is directly or indirectly connected with the contact part; an electromagnet is arranged and is directly or indirectly connected with a spherical bearing stator of the spherical bearing; magnetic force is generated between the electromagnet and the permanent magnet, and the magnetic force drives the contact component to rotate by taking the rotation center of the spherical bearing as the rotation center; and a limiting structure is arranged and is directly or indirectly connected with a spherical bearing stator of the spherical bearing, and the limiting structure is used for restraining the rotation range of the contact part or restraining the rotation and movement range of the contact part.

Optionally:

the spherical bearing and/or the contact member are cooled by liquid cooling and/or air cooling.

( Explanation: indirect connection refers to two components that make a connection with the other components as a connection intermediary; an electromagnet is a component that generates a magnetic field after being energized, for example, consisting of silicon steel and a coil. )

Optionally:

the contact area is detachable or the contact area and other areas of the contact part are connected into a whole and are not detachable, and the spherical bearing is used as an intermediary for connecting the contact part with a printing head of the three-dimensional printer; the spherical bearing is hollow, and the printing raw material passes through the hollow area of the spherical bearing and then passes through the channel of the contact part and reaches the surface of the workpiece in the three-dimensional printing process; a permanent magnet is arranged and is directly or indirectly connected with the contact part; an electromagnet is arranged and is directly or indirectly connected with a spherical bearing stator of the spherical bearing; magnetic force is generated between the electromagnet and the permanent magnet, and the magnetic force drives the contact component to rotate by taking the rotation center of the spherical bearing as the rotation center;

Optionally:

the permanent magnet is an annular permanent magnet.

Optionally:

the contact area is detachable or is connected with other areas of the contact part into a whole and is not detachable;

the support body is used for installing the contact part, and the contact part is rotatably and movably connected with the connecting bracket through the support body;

The support body adopts a telescopic rod, one end of the telescopic rod is rotatably and directly connected or indirectly connected with the connecting bracket, and the other end of the telescopic rod is rotatably and directly connected or contacted with the contact part, or the other end of the telescopic rod is rotatably and indirectly connected or contacted with the contact part; the telescopic rod drives the contact part to rotate by taking the outlet end of the passage of the contact part as a rotation center;

the spherical bearing and/or the contact part are cooled by liquid cooling and/or air cooling;

the telescopic rod is hydraulically driven, pneumatically driven, magnetically driven, electrically deformed, screw driven or thermally deformed. ( Explanation: the telescopic rod is in a rod shape, has two ends, and is variable in total length and controlled in total length. )

Optionally:

the support body adopts a telescopic rod, one end of the telescopic rod is rotatably and directly connected or indirectly connected with the connecting bracket, and the other end of the telescopic rod is rotatably and directly connected or contacted with the contact part, or the other end of the telescopic rod is rotatably and indirectly connected or contacted with the contact part; the telescopic rod drives the contact part to rotate by taking the outlet end of the passage of the contact part as a rotation center; setting a limiting structure, wherein the limiting structure is used for limiting the rotation range of the contact part or limiting the rotation and movement range of the contact part;

the telescopic rod is hydraulically driven, pneumatically driven, magnetically driven, electrically deformed, screw driven or thermally deformed.

Optionally:

the connecting support is arranged, the connecting support is directly connected or indirectly connected with the contact component through at least 3 telescopic rods, and two ends of each telescopic rod are respectively connected (directly connected or indirectly connected) with the connecting support and the contact component through spherical bearings; the connecting bracket can be connected with a printing head of the three-dimensional printer; in the three-dimensional printing process, the contact position of the contact area on the contact part and the workpiece is controlled by the telescopic rod.

Optionally:

the three-dimensional printer further comprises a connecting support, the connecting support is provided with a part and/or an interface used for being connected with a printing head of the three-dimensional printer, and the contact part is directly or indirectly movably arranged on the connecting support.

According to another aspect of the invention, the invention adopts the following technical scheme:

a three-dimensional printer comprising a print head and further comprising a screeding device for three-dimensional printing as defined in any one of the preceding claims, the screeding device being connected to the print head.

Optionally:

the printing head outputs heating energy to heat the workpiece and/or the printing raw material, wherein the heating mode is one or a combination of at least two of laser heating, electron beam heating, electric arc heating, plasma beam heating, resistance heating and electromagnetic induction heating.

Optionally:

the printing head is connected with the scraping device for three-dimensional printing in a direct or indirect way; the indirect connection means that the printing head and the scraping device for three-dimensional printing are connected by taking other parts as connection intermediaries. (interpretation: other components refer to mechanical components not belonging to the described screeding device and printhead.) optionally:

the printing head is provided with a control circuit, and the control circuit of the printing head comprises a part for controlling the scraping device for three-dimensional printing.

Optionally:

the control circuits of the printing head and the scraping device for three-dimensional printing are arranged in the control circuit of the three-dimensional printer on which the printing head and the scraping device are arranged.

The invention has the main beneficial effects as follows:

(1) The contact part is provided with a channel for the printing raw material to pass through, the channel is provided with an inlet end and an outlet end, the printing raw material enters the channel from the inlet end and leaves the channel from the outlet end in the three-dimensional printing process, one side of the contact part, which is close to a workpiece, is provided with a contact area surrounding the outside of the outlet end of the channel, and the contact area is contacted with an area which is not completely solidified of the workpiece so as to regulate the shape of the area which is not completely solidified of the workpiece; in addition, in the process of morphology regulation and control of the area of the workpiece which is not completely solidified by the contact component, the contact component can move relative to the workpiece in the direction which is not parallel to the current molding surface of the workpiece, so that the deposited surface of the workpiece which is not completely solidified can be synchronously scraped and extruded for forging in the three-dimensional printing molding process, the structure is very simple, the volume is small, the manufacturing cost is low, and the contact component can be integrated onto the existing printing head in the technical field of three-dimensional printing and has high applicability.

(2) In the process of carrying out morphology regulation on the area which is not completely solidified of the workpiece by the contact component, the contact component can be contacted with the area which is not completely solidified of the workpiece surface (comprising printing raw material which is just deposited and is not completely solidified) and also can be contacted with the completely solidified area of the workpiece surface, and the completely solidified area of the workpiece surface cannot be absolutely flat (for example, the surface has a height fluctuation of +/-10 microns), so the contact component can move relative to the workpiece in the direction which is not parallel to the current molding surface of the workpiece surface, can provide elastic buffer for rigid contact between the contact component and the completely solidified area of the workpiece surface, and can adapt to the fluctuation of the morphology of the workpiece/printing body surface at a high speed; therefore, the friction between the contact part and the workpiece is small, jamming can not occur, and the smooth and reliable printing process is ensured; the screeding device for three-dimensional printing of the present invention can be effectively integrated into existing printheads in the field of three-dimensional printing technology, in particular direct energy deposition (Directed Energy Deposition, DED) printheads.

(3) The surface of the outlet end of the channel of the contact part is not parallel to the current forming surface of the workpiece surface, namely an acute angle is formed between the surface of the contact part and the current forming surface of the workpiece surface, and the opening direction of the angle can be changed along with the change of the deposition direction of the printing raw material on the workpiece surface, so that in the process of performing morphology regulation and control on the area of the workpiece which is not completely solidified by the contact part, only part of the area of the contact part is contacted with the workpiece, and the angle between the surface of the outlet end of the channel of the contact part and the current forming surface of the workpiece surface can be used for performing transition and guiding on the contact process.

(4) The surface of the outlet end of the channel of the contact component is not parallel to the current forming surface of the workpiece surface, namely an acute included angle exists between the surface and the current forming surface, the opening of the included angle faces the advancing direction of a deposition path when the printing raw material is deposited on the workpiece surface, and the direction of the opening of the included angle can be switched at a high speed.

(5) The surface of the outlet end of the channel of the contact component is not parallel to the current forming surface of the workpiece surface, namely an acute included angle exists between the surface and the current forming surface, and the opening of the included angle faces the advancing direction of a deposition path when the printing raw material is deposited on the workpiece surface; the area of the contact part, which is positioned at one side of the included angle opening, is suspended in the air, and the area of the contact part, which is positioned at the top side of the included angle, is contacted with the deposited unset printing raw material; because of the included angle, the present invention ensures that only the just deposited printing material and its peripheral small area are contacted and scraped, which can provide benefits such as: small resistance, small vibration and small driving force required by scraping.

(6) The surface of the outlet end of the channel of the contact component is not parallel to the current forming surface of the workpiece surface, namely an acute included angle exists between the surface and the current forming surface, and the opening of the included angle faces the advancing direction of a deposition path when the printing raw material is deposited on the workpiece surface; the area of the inner wall of the raw material channel of the contact part, which is positioned at one side of the included angle opening, is far away from the printing raw material being deposited, the space of the raw material channel, which is positioned at one side of the included angle opening, is enlarged, an energy beam (such as a laser beam and a plasma beam) for heating a workpiece to generate a molten pool on the current forming surface of the workpiece surface is provided with a passage, and the area of the inner wall of the raw material channel of the contact part, which is positioned at the top side of the included angle, is close to the printing raw material being deposited (molten raw material), so that the contact part can be contacted with the printing raw material just before the printing raw material being deposited is enabled to be faster, complete solidification of the printing raw material just before the printing raw material being deposited is enabled to be prevented, the printing raw material just before the printing raw material being deposited is enabled to be completely solidified before the contact part is contacted with the contact part is enabled to be ensured, and the mechanical force required for the scraping action is smaller when the printing raw material being deposited is close to the printing raw material being deposited (molten raw material) is enabled to be close to the printing raw material being deposited in a molten state. Therefore, the invention can effectively scrape off the printing material which has been deposited and has not been completely solidified.

(7) The surface of the outlet end of the channel of the contact component is not parallel to the current forming surface of the workpiece surface, namely an acute angle is formed between the surface and the current forming surface, the opening of the angle faces the advancing direction of a deposition path of printing raw materials when the printing raw materials are deposited on the workpiece surface, the change of the advancing direction of the deposition path of the printing raw materials can be adapted by adjusting the orientation of the opening of the angle, and the high-speed switching of the orientation of the opening of the angle can be supported only by a simple mechanical structure, for example: the method comprises the steps that a hollow spherical bearing is arranged, the spherical bearing comprises a spherical bearing stator arranged on the support body and a spherical bearing rotor arranged on the contact part, raw materials are printed in the three-dimensional printing process, pass through a raw material channel of the contact part and reach the surface of a workpiece after passing through a hollow area of the spherical bearing, and the high-speed switching of the direction of an included angle can be realized through magnetic force driving; therefore, the invention has the advantages of simple structure, small volume, low manufacturing cost and high applicability, and can be integrated on the existing printing head in the technical field of three-dimensional printing.

(8) The contact part is contacted with the printing raw material after the printing raw material (molten raw material) finishes depositing, so that the temperature of the contact part does not interfere with the printing raw material before the printing raw material finishes depositing, and the contact part can be cooled (such as water cooling) so that the contact part can work for a long time to meet the requirement of long-time work of the three-dimensional printing system.

(9) The invention in-situ screeds the printing raw materials which are just deposited and are not completely solidified in real time in the three-dimensional printing process, so that the surface of each forming layer is always in a flat state, the consistency and controllability of the deposition surface (forming surface) based on the deposition of all the fused printing raw materials can be ensured, the controllability of the three-dimensional printing process is extremely high, the repeatability is high, and the shape, the precision, the surface morphology and the like of the finally printed and formed part become highly controllable.

(10) The invention scrapes the printing raw material which is just deposited and is not completely solidified in the three-dimensional printing process, and the scraping translation has extrusion effect; the grains inside the freshly deposited and not yet fully solidified printing stock are broken by mechanical forces, the internal voids and thermal cracks are crushed and collapsed, and the material becomes denser, which beneficial effects give the final printed shaped metal part forging grade properties, such as high fatigue strength. The local small area in the softened state or the molten state is scraped, the required driving force is small, a large power system (such as a jack) is not needed, and the required realization structure is simple and can be directly integrated on the printing head. The invention enables the metal three-dimensional printing process to synchronously integrate the mechanical forging function in situ.

(11) The contact part contacts the area which is not completely solidified (including the printing raw material which is just deposited and not completely solidified) on the surface of the workpiece in the three-dimensional printing process, the contact part fully contacts the printing raw material which is just deposited and not completely solidified in the scraping process, the contact part rapidly cools the fully contacted area, the heat input and the local heat accumulation of the workpiece are reduced, the deformation (such as warping) of the workpiece is restrained, the yield and the final forming precision of the printed part are improved, and the stress is reduced; also, since the printing raw material which has just been deposited and has not yet been completely solidified is rapidly cooled by the contact member with which it is sufficiently contacted, this has significant advantages for a structure in which the printing heat dissipation condition is poor (for example, a thin-walled structure in which the position is high), such as: the structure defect caused by flowing of the printing raw material which is just deposited and is not completely solidified is avoided, and high-speed printing can be realized without reducing the deposition rate of the melting raw material to give time for heat dissipation.

In summary, the present invention has many beneficial effects, for example: the technical scheme of the invention solves the problem that the surface of a workpiece is difficult to be scraped or trowelled in real time in the process of directly carrying out energy deposition (Directed Energy Deposition, DED) metal three-dimensional printing; the contact area with the surface of the workpiece is only concentrated on the printing raw material which just finishes deposition and the small-range area around the printing raw material, so that the resistance between the printing raw material and the workpiece is small in the three-dimensional printing process, the vibration is small, the blockage can not occur, and the high-speed three-dimensional printing can be supported; the scraping device for scraping the incompletely solidified area on the surface of the workpiece can switch the directions at a high speed, can effectively scrape the deposited incompletely solidified printing raw material, and can support real-time scraping and in-situ micro-mechanical forging in the high-speed three-dimensional printing process; the controllability and the repeatability of the direct energy deposition three-dimensional printing process are high, so that the shape, the precision, the surface morphology and the like of the finally printed and molded part become highly controllable; the method can quickly cool the area where the fused printing raw material is just deposited, reduce the heat input and local heat accumulation of the workpiece, improve the printing speed of the structure with poor heat dissipation, such as a thin-wall structure, a hollow structure and the like, inhibit the deformation (such as warping) of the workpiece, improve the yield and final forming precision of printed parts, and reduce the stress. The present invention is a substantial advance.

Drawings

Fig. 1 to 6 are views for explaining the principle of a main body portion of a first embodiment of a screeding device for three-dimensional printing of the present invention; wherein: FIG. 1 is a three-dimensional perspective view; FIG. 2 is a three-dimensional cross-sectional view of FIG. 1; FIG. 3 is a partial exploded view of FIG. 1; FIG. 4 is a three-dimensional perspective view showing the embodiment shown in FIG. 1 from another perspective; FIG. 5 is a side view of the particular embodiment shown in FIG. 1; FIG. 6 is a two-dimensional cross-sectional view taken along a vertical plane passing through the center symmetry axis in the left-right direction of FIG. 5;

fig. 7 to 10 are schematic diagrams of a three-dimensional printer (only characteristic structures are shown) to which the screeding device for three-dimensional printing shown in fig. 1 to 6 is applied; wherein: FIG. 7 is a partial three-dimensional schematic of a three-dimensional printer; FIG. 8 is a three-dimensional cross-sectional view of FIG. 7; FIG. 9 is a two-dimensional schematic diagram for explaining a printing process of the three-dimensional printer shown in FIG. 7 at a certain timing; fig. 10 is an enlarged view of a portion indicated by a dashed box CC in fig. 9;

fig. 11 to 15 are views for explaining the principle of a second embodiment of a screeding device for three-dimensional printing of the present invention; wherein: FIG. 11 is a three-dimensional perspective view illustrating a component for doctoring an unset area of a workpiece surface of this particular embodiment; FIG. 12 is a three-dimensional cross-sectional view of FIG. 11; FIG. 13 is a three-dimensional perspective view showing the bottom structure of the component shown in FIG. 11; FIG. 14 is a three-dimensional perspective view of a second embodiment of a screeding device for three-dimensional printing according to the present invention based on the components shown in FIG. 11; FIG. 15 is a three-dimensional cross-sectional view of FIG. 14;

Fig. 16 to 17 are schematic diagrams of a three-dimensional printer (only characteristic structures are shown) to which the screeding device for three-dimensional printing shown in fig. 11 to 15 is applied; wherein: FIG. 16 is a partial three-dimensional schematic of a three-dimensional printer; FIG. 17 is a three-dimensional cross-sectional view of FIG. 16;

fig. 18 to 19 are schematic diagrams for explaining the principle of a main body portion of a third embodiment of a screeding device for three-dimensional printing and a three-dimensional printer to which the embodiment is applied according to the present invention; wherein fig. 19 is an enlarged view of a portion indicated by a broken line frame DD in fig. 18;

wherein the reference numerals:

1-supporting body, 11-spherical bearing stator, 12-via hole I, 13-column I, 14-cooling channel, 151-cooling liquid interface I, 152-cooling liquid interface II, 161-constraint arm I, 162-constraint arm II, 163-constraint arm III, 164-constraint arm IV,

2-contact part, 21-disk, 22-spherical bearing rotor, 23-via two, 24-annular end face one,

251-virtual sphere center, 252-virtual sphere one, 253-virtual sphere two,

3-ring-shaped strong magnet, 31-electromagnet I, 32-electromagnet II, 33-electromagnet III, 34-electromagnet IV,

41-spring plate I, 42-spring plate II, 43-spring plate III, 44-spring plate IV,

51-connecting bracket I, 52-compression spring, 53-raw material conveying channel I, 54-linear solid raw material I, 551-laser beam I, 552-laser beam II, 553-laser beam III, 554-laser beam IV, 555-current working laser beam,

561-work piece, 562-current shaping layer, 563-base plate, 564-puddle, 565-molten printing material that has been deposited, 566-printing material that has not yet been fully solidified,

57-a resistance heating power source,

61-connecting body, 62-contact head II, 63-via hole III, 64-annular end face II, 65-cooling cavity II, 661-cooling liquid interface III, 662-cooling liquid interface IV, 671-ball joint bearing seat I, 672-ball joint bearing seat II, 673-ball joint bearing seat III,

71-a connecting bracket II, 721-a ball joint bearing seat IV, 722-a ball joint bearing seat V, 723-a ball joint bearing seat six, 732-a position sensor II, 733-a position sensor III, 741-an electromagnetic telescopic rod I, 742-an electromagnetic telescopic rod II, 743-an electromagnetic telescopic rod III,

75-aluminum droplet ejector, 76-nozzle.

Detailed Description

The invention is described in detail below with reference to the accompanying drawings, which illustrate preferred embodiments of the invention.

In the description of all the embodiments of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., are used for convenience of description and simplicity of operation only, and do not indicate or imply that the devices or elements in question must have a particular orientation, be constructed and operate in a particular orientation, based on the orientation or positional relationship shown in the drawings.

The main body portion of a first embodiment of a screeding device for three-dimensional printing of the present invention as shown in fig. 1 to 6: a contact member for making contact with an area of the workpiece which has not been completely solidified during three-dimensional printing is provided; morphology control is performed on the not yet fully solidified region of the workpiece (workpiece 561 in fig. 9 and 10) by the contact of the contact member with the not yet fully solidified region of the workpiece; the workpiece (also called a printing body) refers to an object formed after the printing raw materials are deposited in the three-dimensional printing process; ( Explanation: the melted printing raw material is converted into a part of a workpiece after the deposition is finished, the raw material which is deposited but not solidified and the area of the workpiece which is heated, remelted and softened by the heating energy belong to the area which is not completely solidified of the workpiece, before the raw material which is deposited on the surface of the workpiece is completely solidified, the contact part can be contacted with the raw material which is not completely solidified and is deposited, or can be contacted with the raw material which is not completely solidified and is deposited and other areas of the workpiece at the same time, and the surface morphology of the raw material which is not completely solidified is trimmed, namely, the surface morphology of the raw material which is deposited is scraped off by mechanical force; )

The key point of the invention is that:

the contact part (namely the contact part 2) is provided with a channel (namely a second through hole 23) for printing raw materials to pass through, and the channel is provided with an inlet end and an outlet end; in the three-dimensional printing process, printing raw materials enter the channel from the inlet end and leave the channel from the outlet end, one side of the contact component, which is close to the workpiece, is provided with a contact area (namely an annular end surface I24) which surrounds the outside of the outlet end of the channel, and the contact area (namely the annular end surface I24) is in contact with an area of the workpiece which is not completely solidified;

in the process of performing morphology regulation (screeding) on the area (such as the molten printing raw material 565 which is deposited and the printing raw material 566 which is not completely solidified in fig. 10) of the workpiece which is not completely solidified by the contact component, the surface of the outlet end of the channel is not parallel to the current molding surface of the workpiece surface, that is, an acute angle exists between the surface and the current molding surface, and the direction of the opening of the angle can be changed along with the change of the deposition direction of the printing raw material on the workpiece surface, so that the contact component can move relative to the workpiece in the direction which is not parallel to the current molding surface of the workpiece surface; here, the current molding surface of the workpiece surface is a surface on which the current molding region of the current molding layer in the three-dimensional printing layer-by-layer molding process is based (e.g., a surface of the workpiece 561 on which the molten printing material is being deposited, the molten printing material 565 that has completed deposition, and the printing material 566 that has not yet been solidified are based in connection with the end/front end of the linear solid material one 54 in fig. 9 and 10).

The contact area may be a plane or a curved surface, and the contact area of this embodiment is designed to be a plane, i.e. the annular end face one 24, and the plane where the outlet end of the channel is located is coplanar with the plane where the contact area is located (i.e. the plane where the annular end face one 24 is located), so that the acute included angle between the plane where the outlet end of the channel of the contact component is located and the current forming surface of the workpiece surface (i.e. the included angle indicated by θ1 in fig. 9 and 10) is the included angle between the annular end face one 24 and the current forming surface of the workpiece surface. In other embodiments, as shown in fig. 18 and 19, the contact area may be designed as a curved surface, that is, the first annular end surface 24 is a curved surface, the surface 25 of the outlet end of the channel is tangent to the first annular end surface 24, and the acute angle between the surface 25 of the outlet end of the channel of the contact member 2 and the current forming surface of the workpiece surface is the angle indicated by θ1 in fig. 18 and 19.

The orientation of the opening of the included angle theta 1 is variable; the opening of the included angle θ1 faces the advancing direction of the deposition path of the printing raw material when the printing raw material is deposited on the surface of the workpiece (for example, the current deposition path advancing direction indicated by an arrow D1 in fig. 9; in the three-dimensional printing process, the deposition path advancing direction of the printing raw material is continuously changed, the direction of the included angle θ1 is also continuously changed to keep the deposition path advancing direction of the printing raw material, it is to be noted that the opening of the included angle θ1 and the deposition path advancing direction of the printing raw material may not completely coincide, whether completely coincide or not, which may be controlled by a control program/control software, and may be set).

The main body of this embodiment comprises two main parts, namely: a support body 1 and a rotating body (also referred to as a swinging body).

The support body 1 is used for installing the contact part 2, and the contact part 2 is connected with the connecting bracket (the first connecting bracket 51) in a relatively rotatable and relatively movable way through the support body 1; the support body 1 and the first connection bracket 51 are movable relative to each other, so that the contact member 2 and the first connection bracket 51 are movable relative to each other. Specifically, the support body 1 includes a spherical bearing stator 11, a column one 13, 4 constraint arms (constraint arm one 161, constraint arm two 162, constraint arm three 163, and constraint arm four 164), 4 groups of electromagnets (electromagnet one 31, electromagnet two 32, electromagnet three 33, and electromagnet four 34), and 4 groups of spring pieces (spring piece one 41, spring piece two 42, spring piece three 43, and spring piece four 44); wherein: the cylinder I13 is a hollow cylinder, the middle lower end of the cylinder I13 is connected with the upper end of the spherical bearing stator 11, and 4 constraint arms are equiangularly and symmetrically distributed on the periphery of the cylinder I13; an annular cooling cavity channel 14 is arranged in the first cylinder 13, and the cooling cavity channel 14 exchanges cooling liquid with an external heat dissipation system through a first cooling liquid interface 151 and a second cooling liquid interface 152, so that heat of the support body 1 and the rotating body is conducted away; the spherical bearing stator 11 is a hollow hemispherical body, and a first through hole 12 for passing through printing raw materials is arranged at the lower end of the spherical bearing stator; during three-dimensional printing, heating energy (e.g., a laser beam), printing material, and a first printing material pass through the central spaces of the cylinder one 13 and the spherical bearing stator 11 and the first through hole 12; one of the 4 groups of electromagnets is respectively arranged on one group of the 4 constraint arms, each group of electromagnets consists of silicon steel and a coil, and the silicon steel extends to the inner face of the constraint arm; one of 4 sets of spring pieces is respectively arranged in one set of 4 constraint arms, and the 4 sets of spring pieces are used for determining the initial position of the disc 21 of the rotator before the electromagnet is electrified; the 4 constraint arms are provided with an inner sphere arc surface, and the 4 inner sphere arc surfaces are concentric and share a spherical surface (a virtual spherical surface two 253 shown in fig. 6) for constraining the movement of a disc 21 (described below) of the rotator. The whole of the contact member 2 of the present embodiment is a rotating body, and the spherical bearing rotor 22 (described below) and its lower end portion (i.e., the contact region of the contact member for making contact with the not yet fully solidified region of the workpiece) are rotatable, and the disc 21 is in the initial position before the electromagnet is energized, at which time the rotation axis of the rotating body is coaxial with the axis of the column one 13 in the vertical direction (in the azimuth relationship shown in fig. 4 to 6). Of course, in other embodiments, the contact area of the contact member used to make contact with the not yet fully solidified region of the workpiece is the rotating body.

The rotor (also called a wobble body) is mainly composed of a disc 21, a spherical bearing rotor 22 and an annular ferromagnetic body 3, wherein: the disc 21 is a circular ring, the spherical bearing rotor 22 is a hollow hemispherical body, and the upper end of the spherical bearing rotor 22 is connected with the inner edge of the disc 21 so as to jointly form the contact part 2; the annular strong magnet 3 adopts a circular annular neodymium-iron-boron magnet; the annular ferromagnetic body 3 is arranged on the upper surface of the disc 21 and concentric; the lower end of the spherical bearing rotor 22 is provided with a second through hole 23 (namely a channel for printing raw materials to pass through, which is arranged on the contact part 2); during the three-dimensional printing process, heating energy (e.g., a laser beam), printing material, passes through the second via 23; the disc 21 is welded to the spherical bearing rotor 22 (i.e. the contact member comprises the disc 21 and the spherical bearing rotor 22).

What needs to be specifically stated is: the spherical bearing stator 11 and the spherical bearing rotor 22 together form a spherical knuckle bearing (the spherical knuckle bearing belongs to one kind of spherical sliding bearing, namely, a spherical bearing); the center of the sliding contact surface of the spherical bearing is a virtual center 251 (see fig. 6), and the sliding contact surface of the spherical bearing is coplanar and concentric with the virtual spherical surface 252; the spherical bearing rotor 22 is also a "contact/wiper" for wiping off incompletely solidified areas of the workpiece surface (e.g., the deposited molten printing material 565 and the incompletely solidified printing material 566 of fig. 10). The sliding contact surface between the spherical bearing stator 11 and the spherical bearing rotor 22 is provided with a thin layer of high-temperature-resistant lubricant with high heat conductivity coefficient. The 4 inner sphere cambered surfaces of the 4 constraint arms share a spherical surface (a virtual spherical surface two 253 shown in fig. 6), and the spherical surface is concentric with the virtual spherical surface one 252. The outer peripheral surface of the disk 21 is an outer spherical surface, and an inner spherical surface combined with 4 constraint arms constitutes a spherical bearing (spherical joint). The rotating body (composed of the disc 21, the spherical bearing rotor 22 and the annular ferromagnetic body 3) is restricted to perform spherical sliding (also belongs to rotation, the rotation center of which is concentric with the sliding contact surface of the spherical joint bearing, namely, the virtual sphere center 251) only by taking the sliding contact surface of the spherical joint bearing as a supporting surface, and moves along with the supporting body 1. The spherical rotation of the spherical bearing rotor 22 is indicated by the double-headed arrow D4 in fig. 2 and 6, and the double-headed arrow D4 represents that the spherical bearing rotor 22 can rotate in any direction within the space defined by the 4 constraint arms (constraint arm one 161, constraint arm two 162, constraint arm three 163, and constraint arm four 164).

In the embodiment, the contact part 2 is driven to rotate in a magnetic driving mode, and a driving device for realizing magnetic driving comprises 4 groups of electromagnets. The 4 groups of electromagnets are indirectly connected with the spherical bearing stator 11 through a column one 13. The magnetic fields generated by the 4 groups of electromagnets (the first electromagnet 31, the second electromagnet 32, the third electromagnet 33 and the fourth electromagnet 34) all exert magnetic force (including thrust and suction) on the annular ferromagnetic body 3. The magnetic force indirectly drives the rotation (also referred to as wobble in this embodiment) of the spherical bearing rotor 22 via the disc 21. Because the annular ferromagnetic body 3 is annular and the constraint actions of the 4 constraint arms, no matter how the disc 21 rotates (swings), magnetic action can be ensured to occur between the electromagnet and the annular ferromagnetic body 3, and the inclination angle and the orientation of the annular end face I24 of the spherical bearing rotor 22 (the acute angle between the annular end face I24 and the current forming surface of the workpiece surface and the orientation thereof in the three-dimensional printing process) can be controlled. During "shaving" of the non-solidified areas of the workpiece surface, the 4 groups of electromagnets are transferred via said contact members 2 to the non-solidified areas of the workpiece surface, i.e. a force directed towards the workpiece is generated. When the acute angle between the annular end face I24 and the current forming surface of the workpiece surface and the orientation of the acute angle are changed, the 4 groups of electromagnets enable the opening side of the angle of the annular end face I24 to be far away from the current forming surface of the workpiece surface, and the top side of the angle of the annular end face I24 is close to the current forming surface of the workpiece surface.

The control software regulates the current magnitude and direction of each group of electromagnets of the 4 groups of electromagnets through the control circuit, and can control the annular ferromagnetic body 3 to incline towards a designated azimuth (according to the azimuth relation shown in fig. 4 to 10, such as the inclination angle shown by theta 2 in fig. 9), so as to regulate the angle value and the direction of the acute angle theta 1 between the surface where the outlet end of the channel of the contact component is positioned (namely the annular end surface I24) and the current forming surface of the workpiece surface. The control software and the control circuit are provided in the three-dimensional printer (i.e., three-dimensional printing system) to which the present embodiment is applied. The magnitude and direction of the current of the electromagnet control the magnetic field intensity and direction of the electromagnet respectively.

The spherical bearing rotor 22 is used as a "contact head/wiper head" (i.e., the body of the contact member) for wiping off the incompletely solidified regions (e.g., the deposited molten printing material 565 and the incompletely solidified printing material 566 in fig. 10) of the surface of the workpiece in the present embodiment, and the contact region (i.e., the lower end portion shown in fig. 4 to 6) for contacting the workpiece is made of a tungsten-copper alloy material (e.g., copper content 25% and tungsten content 75%), which is embedded in the lower end of the spherical bearing rotor 22 in an interference fit manner, and both are sufficiently contacted and not detachable (i.e., the contact region is integral with other regions of the contact member and not detachable). The main body portions of the spherical bearing stator 11 and the spherical bearing rotor 22 are made of nickel-copper alloy materials with high heat conductivity and wear resistance. The coolant indirectly cools the lower end portion of the spherical bearing rotor 22 mainly through a spherical joint bearing (the spherical bearing stator 11 and the spherical bearing rotor 22 are formed together).

A first embodiment of a screeding device for three-dimensional printing according to the present invention is provided with means for connection to a print head of a three-dimensional printer, i.e. a first connection bracket 51 shown in fig. 7 to 9, the contact member 2 being rotatable and movable relative to the first connection bracket 51. Specifically, the first connecting bracket 51 is also a rotating body, and its axis is coaxial with the first column 13 of the support body 1. The lower end cylinder of the first connecting bracket 51 is sleeved on the outer circumferential surface of the first cylinder 13, and the first cylinder 13 can slide up and down relative to the axial direction of the first connecting bracket 51 (as shown by a double-headed arrow D3 in fig. 9). A spring (i.e., a compression spring 52) is provided between the first connection bracket 51 and the first cylinder 13, and the compression spring 52 is outside the lower cylinder of the first connection bracket 51. The compression spring 52 also generates a force directed toward the workpiece, maintaining the lower end of the spherical bearing rotor 22 in contact with the workpiece (during three-dimensional printing). The first column 13 can slide up and down relative to the axial direction of the first connecting bracket 51, and is used for relatively large displacement (for example, 2mm displacement) in the vertical direction (in the azimuth relation shown in fig. 4-10) generated by sudden collision between the lower end of the opposite spherical bearing rotor 22 and a workpiece or other objects (for example, metal beads accidentally contaminating the surface of the workpiece): when the collision occurs, the movement of the current molding surface far from the workpiece surface is generated, and when the collision is finished, the movement of the current molding surface close to the workpiece surface is generated. The compression spring 52 also belongs to the driving means (in the form of mechanical spring driving) in this embodiment, and the compression spring 52 is also used to drive the contact element 2 to move relative to the first connecting bracket 51.

In the three-dimensional printing process, the acute included angle θ1 between the surface of the outlet end of the channel of the contact member 2 (i.e. the surface of the annular end face one 24) and the current forming plane of the workpiece surface is variable, which includes 3 cases: 1, when the direction of the included angle is switched, the angle of theta 1 is changed before reaching a preset value in the switching process; 2, the angle value of theta 1 is controllable; 3, when the annular end surface 24 of the lower end portion of the contact member is in rigid contact with the completely solidified region (rigid) of the workpiece surface (including small-scale collision due to minute undulation of the surface of the completely solidified region of the workpiece surface), small fluctuations in the angle θ1 occur. For this 3 rd case, the angle of θ1 is achieved by magnetic actuation in this embodiment, which allows for small fluctuations in angle of θ1 when the annular end surface 24 is in rigid contact with the minute undulating region of the workpiece surface (e.g., a swing of ±50 microns) due to the non-contact, spatial damping of the magnetic actuation, and the non-rigid magnetic actuation. Preferably, the angle value of the included angle θ1 is rapidly varied at a set frequency (e.g. 200 Hz), and the 0 ° - > preset value (belonging to the acute angle) - > … …) is periodically varied, so that the impact of a specific frequency can be performed on the area of the workpiece that is not yet completely solidified, and the deposited printing raw material is prevented from being accumulated at the channel (i.e. the second via 23) of the contact member 2. Thus, this embodiment has the ability to resist irregularities in the surface of the workpiece (the surface of the workpiece is not absolutely flat), and no jamming occurs.

A three-dimensional printer (a housing of the three-dimensional printer, a connection bracket between components, and the like, non-characteristic structures are omitted) to which the screeding device for three-dimensional printing shown in fig. 1 to 6 is applied as shown in fig. 7 to 10: a raw material conveying channel (namely, a raw material conveying channel I53) is arranged, and linear solid raw material (namely, linear solid raw material I54) is guided by the raw material conveying channel I53 to be fed to the surface of a workpiece (in the direction shown by an arrow D2 in fig. 9); the lower end of the first raw material conveying channel 53 adopts a tungsten-copper alloy conducting nozzle, and the central axis of the tungsten-copper alloy conducting nozzle is coaxial with the first through hole 12; the first linear solid raw material 54 is a stainless steel wire with a wire diameter of 1.0 mm; heating the workpiece (i.e., workpiece 561) with the laser beams (including laser beam one 551, laser beam two 552, laser beam three 553, and laser beam four 554) to produce a melt pool (i.e., melt pool 564) and to assist in heating the front (lower) end of the first linear solid feedstock 54; in the three-dimensional printing process, a first layer is printed on the basis of a stainless steel plate (namely a bottom plate 563); the first material conveying path 53 and the bottom plate 563 are electrically connected to the output interface of the resistance heating power supply 57, respectively, and the current output from the resistance heating power supply 57 is conducted through the first material conveying path 53 and the bottom plate 563, and the current flows through the first linear solid material 54, and heats and melts the front end of the first linear solid material 54, which is in contact with the workpiece 561, by means of resistance heating (printing the second layer and the subsequent layers), or heats and melts the front end of the first linear solid material 54, which is in contact with the bottom plate 563, by means of resistance heating (printing the first layer), and the resistance heating is dominant (more than 90%) in the total energy of melting the front end of the first linear solid material 54. The puddle 564 created by the current heating of the working laser beam 555 is a thin layer puddle, the depth of the puddle 564 is about 50 microns, and the width of the puddle 564 is slightly larger than the line width of the deposited melted printing material formed on the surface of the workpiece. This particular embodiment of the three-dimensional printer is equipped with 4 sets of optical components (not shown in the figures) for projecting and moving 4 laser beams for scanning heating. The scanning heating means: the spot of the laser beam projected on the surface of the workpiece 561 centers on the surface of the workpiece 561 on the area of the workpiece 561 that is contacting the melted printing stock connected to the front end of the line-shaped solid stock 54, heating is moved at the edge of this area, and at the same time the heating area of the laser at the edge of this area moves together with the print head relative to the workpiece 561. If 4 laser beams (including laser beam one 551, laser beam two 552, laser beam three 553, and laser beam four 554) are simultaneously scanned for heating, an annular heating zone surrounding the periphery of the molten printing stock attached at the front end of the line-shaped solid stock one 54 can be combined at the surface of the workpiece 561. The present embodiment of the three-dimensional printer is provided with a wire straightening device (not shown in the drawings) and a micro wire feeder (not shown in the drawings) through which the first linear solid feedstock 54 is straightened (straightened) before entering the first feedstock delivery path 53. The control software and the circuit of the three-dimensional printer are provided in a three-dimensional printer (three-dimensional printing system) to which the three-dimensional printer is mounted.

The working process of the specific embodiment of the three-dimensional printer shown in fig. 9 and 10: the linear solid raw material I54 is guided by the raw material conveying channel I53, passes through the inner space of the spherical bearing stator 11, the first through hole 12 and the second through hole 23 of the spherical bearing rotor 22, and is fed to the surface of the workpiece 561 (in the direction indicated by an arrow D2 in FIG. 9); the first linear solid raw material 54 is fed to the surface of the workpiece 561, and the front end of the first linear solid raw material is heated and melted by the current output by the resistance heating power supply 57 to generate a melted printing raw material; the forward direction of the deposition path of the molten printing material on the surface of the workpiece 561 at the present moment is shown by an arrow D1, the forward direction of the deposition path of the molten printing material being deposited at this time is beneficial to the coverage of the scanning heating zone of the present working laser beam 555 (the present working laser beam 555 is one of 4 laser beams), the other 3 laser beams are not working, the present working laser beam 555 heats the forward direction of the molten printing material being deposited (the direction shown by an arrow D1) and generates a molten pool 564 after passing through the first via hole 12 and the second via hole 23, and the side of the surface of the linear solid material 54 located in front of the deposition path of the molten printing material is preheated; the rear of the molten printing material being deposited (opposite to the direction of travel of the deposition path) is not heated by the laser beam; the opening direction of the included angle theta 1 between the annular end surface I24 of the lower end of the spherical bearing rotor 22 and the current molding surface of the workpiece 561 faces the advancing direction of the deposition path of the molten printing material shown by the arrow D1, and the opening direction of the included angle theta 1 completely coincides with the advancing direction of the deposition path of the molten printing material shown by the arrow D1; the included angle θ1 provides a transition and guide for the contact process between the annular end face one 24 and the surface of the workpiece 561;

The area of the annular end face one 24 on the opening side of the included angle θ1 is inclined upward, the difference in height between the highest area and the lowest area of the annular end face one 24 at this time is h2 (assuming that the current molding surface of the workpiece 561 is located directly below, that is, in the azimuth relationship shown in fig. 9 and 10), and the difference in height between the lowest area of the annular end face one 24 and the current molding surface of the workpiece 561 is h1; h1 is the layer thickness of the current shaping layer 562; only the lowest area of the annular end face one 24 is in contact with the surface of the workpiece 561, and the contact area is limited to the printing material 566 which is not yet fully solidified and the peripheral small area thereof, if the moving speed in the direction indicated by the arrow D1 reaches a certain threshold value, the printing material 566 which is not yet fully solidified remains in a molten state, the threshold value being related to various factors (such as heating power, heat dissipation condition, material type, distance L1 between the inner wall of the second via hole 23 located on the top side of the included angle θ1 and the center of the front end of the linear solid material one 54), an empirical value can be obtained through a plurality of tests; the embodiment adopts a resistance heating mode to melt the front end of the metal wire to generate molten printing raw materials, and the heating mode enables the inside and outside of the front end of the metal wire to synchronously generate heat, so that high-speed three-dimensional printing, for example, the deposition moving speed of more than 100mm/s can be supported, the lowest area of the annular end face I24 can be supported to contact the molten printing raw materials after deposition, and an excellent scraping effect can be obtained; the ratio between L2 (the distance between the inner wall of the second via 23 on the opening side of the included angle θ1 and the center of the front end of the first linear solid material 54) and L1 (the distance between the inner wall of the second via 23 on the top side of the included angle θ1 and the center of the front end of the first linear solid material 54) mainly depends on the angle value of θ1, and the larger the angle value of θ1, the larger the ratio; on the premise that the inner diameter of the second via hole 23 is unchanged, after the angle value of θ1 reaches a certain threshold, that is, L1 is smaller than a certain threshold, the space corresponding to L1 cannot pass through the laser beam, and the space corresponding to L2 is more suitable for passing through the laser beam, so that the heating strategy of adopting a single laser beam to heat the front part of the deposition path of the molten printing raw material being deposited is more suitable for the embodiment. After deposition of the printing stock, the deposited molten printing stock 565 and the not yet fully solidified printing stock 566 are formed and scraped off by the area of the annular end face 24 on the top side of the included angle θ1, forming part of the current build-up layer 562. This embodiment only contacts and screeds the just-deposited printing material and its peripheral small area, which can provide benefits such as: the printing head has the advantages of small resistance, small vibration, small driving force required by scraping, no need of a large power system (such as a jack), simple required structure and direct integration on the printing head. The printing raw material which is just deposited and is not completely solidified is scraped and translated, and the scraping and translation has an extrusion effect; the invention enables the three-dimensional printing process of the metal to synchronously integrate in-situ mechanical forging functions. The molten pool is obtained by remelting the surface of the workpiece by heating energy, and the pressing force applied by the annular end face one 24 in the process of shaving the unset printing raw material just after completion of the deposition is transmitted to the remelting region of the workpiece, so that the remelting region of the workpiece is forged again in the shaving action of the annular end face one 24. The final forging effect of the three-dimensional printed part needs to be further improved by optimizing parameters such as the remelting area of the workpiece, particularly the area, the depth and the like of a molten pool. In the solidification process of the molten metal, internal grains grow, if the growth process is not damaged, the grains grow into coarse grains (crystal branches), and the mechanical property is poor. If mechanical pressure (such as rolling and hammering) is applied to the molten metal during solidification (including softening stage), the growth process of the crystal grains can be broken to obtain small broken crystal grains, and meanwhile, the mechanical pressure can also crush and collapse internal pores (such as bubbles mixed into the molten metal or generated by metal gasification), hot cracks, so that the material becomes denser, the fatigue resistance is improved, and the stress is reduced. This is the main principle of "forging". The problem that the fatigue resistance of printed parts is not high exists in the existing metal three-dimensional printing technology generally, and the problem is a huge obstacle for restricting the application of the existing metal three-dimensional printing technology in industrial production.

The annular end face I24 fully contacts the printing raw material which is just deposited and is not completely solidified in the process of executing the scraping, the fully contacted area is cooled, the heat input and the local heat accumulation of the workpiece are reduced, the deformation (such as warping) of the workpiece is restrained, and the stress accumulation is reduced; also, because the freshly deposited and as yet not fully solidified printing material cools rapidly, this has significant benefits for structures with poor print heat dissipation conditions (e.g., thin wall structures with higher positions), such as: the structural defect caused by flowing of the printing raw material which is just deposited and is not completely solidified is avoided, and high-speed printing can be realized without reducing the deposition rate of the fused printing raw material to give time for heat dissipation.

In this embodiment, the melted printing stock does not contact the inner walls of the second via 23 until deposition is completed. The molten printing raw material contacts the annular end face I24 after being deposited, and the relative low temperature of the annular end face I24 cannot influence the deposition process of the molten printing raw material; the annular end face one 24 is always in a lower temperature state that is not eroded by the molten printing material, ensuring that it is not damaged by contact with unset metal during long-term three-dimensional printing.

A second embodiment of a screeding device for three-dimensional printing of the present invention as shown in fig. 11 to 15 is mainly different from the first embodiment in that: the scraping device of the present embodiment is mainly composed of a rotating body (also referred to as a swinging body), a connecting bracket (a second connecting bracket 71), and a supporting body, and the rotating body is connected to the connecting bracket by the supporting body so as to be rotatable and movable relative to each other.

The rotor mainly comprises a connector 61 and a second contact 62, wherein: the connecting body 61 is of a plate-shaped structure with an inner circle and an outer triangle, an inner round hole of the connecting body 61 is connected with an upper opening part of the second contact head 62, 3 corners of the connecting body 61 are provided with a ball joint bearing seat (comprising a ball joint bearing seat I671, a ball joint bearing seat II 672 and a ball joint bearing seat III 673), an annular cooling cavity channel II 65 is arranged in the connecting body 61, and the cooling cavity channel II 65 exchanges cooling liquid with an external cooling system through a cooling liquid interface III 661 and a cooling liquid interface IV 662 (not shown in the drawing); the second contact head 62 is a hemispherical body, the lower end of the second contact head is provided with a third through hole 63, the third through hole 63 is used for allowing printing raw materials to pass through, and the second annular end surface 64 of the lower end of the second contact head 62 is used for contacting an unset area on the surface of a workpiece in the three-dimensional printing process and performing scraping translation; the connector 61 and the second contact 62 are welded together to form the contact member.

The second connection bracket 71 is a rotating body, the central area is an interface connected with the printing head, the periphery of the second connection bracket is symmetrically distributed with 3 ball joint bearing seats (including a fourth ball joint bearing seat 721, a fifth ball joint bearing seat 722 and a sixth ball joint bearing seat 723) in equal angles, and the second connection bracket 71 is provided with 3 position sensors (two of which are a second position sensor 732 and a third position sensor 733, and the third one is not shown in the drawing). The position sensor adopts a laser ranging sensor, the laser ranging sensor acquires the distance of the connecting body 61 relative to the laser ranging sensor in real time, and the control software can calculate the state information such as the current position, the inclination angle, the moving speed and the like of the connecting body 61 according to the data of the laser ranging sensor. The control software and the control circuit are provided in the three-dimensional printer (three-dimensional printing system) in which the second embodiment is installed. The control circuit is connected with the 3 position sensors and the driving device, and the control circuit controls the position state of the contact part 2 through the driving device according to the detection signals of the 3 position sensors. Of course, in some embodiments, a sensor may not be provided, and the control circuit directly controls the position state of the contact member through the driving device.

The support body includes 3 groups telescopic links, specifically is the flexible electromagnetic telescopic link of magnetic drive (including electromagnetic telescopic link one 741, electromagnetic telescopic link two 742 and electromagnetic telescopic link three 743), and electromagnetic telescopic link's both ends are spherical joint, make up into ball joint bearing (ball joint bearing belongs to one kind of spherical joint bearing) with ball joint bearing to realize that electromagnetic telescopic link's one end and linking bridge rotationally are connected, electromagnetic telescopic link's the other end and contact part rotationally are connected. The movable rod of the electromagnetic telescopic rod is provided with a strong permanent magnet, the shell of the electromagnetic telescopic rod is provided with a coil, and a magnetic field generated by the coil and the permanent magnet of the movable rod act by magnetic force, so that the action of extension or shortening is generated. Double-headed arrows D5, D6, and D7 indicate the telescoping actions of electromagnetic telescoping rod one 741, electromagnetic telescoping rod two 742, and electromagnetic telescoping rod three 743, respectively. Instead of driving the telescopic rod by magnetic force, the telescopic rod can also be driven by hydraulic pressure, pneumatic pressure, electric deformation, screw rod, thermal deformation and the like.

The control software drives the electromagnetic telescopic rods through the control circuit, adjusts the respective states of the 3 electromagnetic telescopic rods, realizes the position state control of the connecting body 61 and the second contact head 62, and finally realizes the control of the inclination angle and the orientation of the second annular end surface 64, that is to say, the included angle and the orientation between the second annular end surface 64 and the current forming surface of the workpiece are controlled by the combination of the 3 electromagnetic telescopic rods in the three-dimensional printing process. The 3 electromagnetic telescopic rod driving connection bodies 61 and the second contact head 62 rotate with the outlet end of the third via hole 63 (the outlet end of the passage of the contact member) as the rotation center.

As shown in fig. 16 to 17, a three-dimensional printer to which the screeding device for three-dimensional printing shown in fig. 11 to 15 is applied: molten aluminum droplets are ejected by an aluminum droplet ejector 75, and a nozzle 76 of the aluminum droplet ejector 75 is provided at the lower end of the aluminum droplet ejector 75; the aluminum droplet ejector 75 is connected with the second specific embodiment of the scraping device for three-dimensional printing of the invention through an interface in the center of the second connecting bracket 71; the nozzle 76 is positioned in the interior space of the second contact head 62 and molten aluminum droplets ejected from the nozzle 76 pass through the third via 63 before being deposited on a workpiece or a forming platen of a three-dimensional printer. The first layer is deposited on the base plate on the forming platform of the three-dimensional printer, and the second layer and above the second layer are deposited on the workpiece. The control software and the circuit of the three-dimensional printer are arranged in a three-dimensional printing system provided with the three-dimensional printer.

Under high temperature conditions (e.g., temperatures above 500 ℃), containers for holding molten metal are generally manufactured from non-metallic materials (e.g., ceramics and quartz) because molten metal is susceptible to melting of the metal in contact therewith. A micro crucible of ceramic material is provided in the aluminum droplet ejector 75, and the nozzle 76 is also made of ceramic material. During three-dimensional printing, the nozzle 76 cannot contact the workpiece, otherwise is extremely fragile. How to achieve the ejection of molten aluminum drops, reference is made to the solution disclosed in U.S. patent publication No. US2015/0273577A1 (application No. 14/228,681).

There are other preferred embodiments of a screeding device for three-dimensional printing according to the present invention, such as: a channel is provided for generating an air flow (e.g. a lateral air flow) that is not perpendicular to the current forming surface of the workpiece, the air flow flowing at least through the inlet end (e.g. in the space where the via-12 of the first embodiment of a screeding device for three-dimensional printing is located) or the outlet end of the channel of the contact member for carrying away debris that may be generated during three-dimensional printing. The gas stream may be a recyclable inert gas (e.g., argon). (the term longitudinal, as opposed to transverse, refers herein to the current forming surface perpendicular to the surface of the workpiece.)

Another example is: the contact member may be detachable, for example: the contact part is cylindrical and provided with a clamping groove, and is installed in a circular mounting hole of a part connected with the contact part and locked through the clamping groove, and the contact part is tightly and fully contacted with the mounting hole to ensure good heat dissipation. Of course, screw connections are also possible, but require the use of anti-loosening measures.

Another example is: the scraping device for three-dimensional printing is not connected with the printing head of the three-dimensional printer, but moves synchronously with the printing head of the three-dimensional printer relative to the workpiece in the three-dimensional printing process.

Another example is: a telescopic rod is arranged, one end of the telescopic rod is directly connected or indirectly connected with an inactive part (namely a spherical bearing stator) of the spherical bearing, and the other end of the telescopic rod is directly connected or contacted with a movable part (namely a spherical bearing rotor) of the spherical bearing, or the other end of the telescopic rod is indirectly connected or contacted with the movable part of the spherical bearing; the telescopic rod drives the contact part to rotate by taking the rotation center of the spherical bearing as the rotation center; setting a limiting structure, wherein the limiting structure is directly connected or indirectly connected with an inactive part of the spherical bearing, and the limiting structure is used for restraining the rotation range of the contact part or restraining the rotation and movement range of the contact part; the spherical bearing and/or the contact part are cooled by liquid cooling and/or air cooling; the telescopic rod is hydraulically driven, pneumatically driven, magnetically driven, electrically deformed, screw driven or thermally deformed.

Another example is: the telescopic rod is arranged, one end of the telescopic rod is directly connected or indirectly connected with the non-movable part of the spherical bearing, and the other end of the telescopic rod is directly connected or contacted with the movable part of the spherical bearing, or the other end of the telescopic rod is indirectly connected or contacted with the movable part of the spherical bearing; the telescopic rod drives the contact part to rotate by taking the rotation center of the spherical bearing as the rotation center; the spherical bearing and/or the contact part are cooled by liquid cooling and/or air cooling; the telescopic rod is hydraulically driven, pneumatically driven, magnetically driven, electrically deformed, screw driven or thermally deformed.

Another example is: the contact part is provided with a rotor of a spherical bearing, the contact area is detachable or the contact area and other areas of the contact part are connected into a whole and are not detachable (including integral molding), and the spherical bearing is used as an intermediary for connecting the contact part with a printing head of the three-dimensional printer; the spherical bearing is hollow, and the printing raw material passes through the hollow area of the spherical bearing and then passes through the channel of the contact part and reaches the surface of the workpiece in the three-dimensional printing process; a permanent magnet is arranged and is directly or indirectly connected with the contact part; an electromagnet is arranged and is directly or indirectly connected with the spherical bearing stator; generating magnetic force action between the electromagnet and the permanent magnet, wherein the magnetic force drives the contact component to rotate by taking the rotation center of the spherical bearing as the rotation center; setting a limiting structure, wherein the limiting structure is directly or indirectly connected with a spherical bearing stator of a spherical bearing, and the limiting structure is used for restraining the rotation range of the contact part or restraining the rotation and movement range of the contact part; the spherical bearing and/or the contact member are cooled by liquid cooling and/or air cooling.

The above description is only for the preferred embodiments of the present invention and should not be taken as limiting the scope of the invention, i.e. the invention is defined by the appended claims and their equivalents and modifications.

Claims

1. A screeding device for three-dimensional printing is provided with a contact member for making contact with an area of a workpiece which has not yet been completely solidified during three-dimensional printing; the contact part is contacted with the area of the workpiece which is not completely solidified, so that the morphology of the area of the workpiece which is not completely solidified is regulated and controlled; the workpiece is an object formed by depositing printing raw materials in the three-dimensional printing process;

the method is characterized in that:

the contact part is provided with a channel for the printing raw material to pass through, and the channel is provided with an inlet end and an outlet end; in the three-dimensional printing process, printing raw materials enter the channel from the inlet end and leave the channel from the outlet end, one side of the contact part, which is close to the workpiece, is provided with a contact area which surrounds the outside of the outlet end of the channel, and the contact area is in contact with an area of the workpiece which is not completely solidified;

2. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

the contact area is a plane or a curved surface;

the included angle is variable.

3. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

the included angle is formed by a plurality of openings, and the openings of the included angle face the advancing direction of a deposition path of the printing raw material when the printing raw material is deposited on the surface of the workpiece.

4. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

5. The screeding device for three dimensional printing as claimed in claim 4, wherein:

a driving device for driving the contact part to rotate or a driving device for driving the contact part to rotate and move is arranged;

the driving device adopts one or a combination of a plurality of driving modes of magnetic force driving, mechanical elastic driving, fluid driving, thermal deformation driving, magnetic deformation driving, electric deformation driving and mechanical screw driving; wherein the magnetic force drives the power of the magnetic force;

6. The screeding device for three dimensional printing as claimed in claim 4, wherein:

setting a limit structure for limiting the rotation range and/or the movement range of the contact part;

7. The screeding device for three dimensional printing as claimed in claim 4, wherein:

the support body and the connecting bracket can move relatively;

the bearing comprises a bearing stator arranged on the support body and a bearing rotor arranged on the contact part, and the rotation of the contact part relative to the support body is guided by the bearing.

8. The screeding device for three dimensional printing as claimed in claim 4, wherein:

a lubricant or heat conducting agent with high heat conductivity is arranged on a direct contact surface or an indirect contact surface between the contact part and the connecting bracket;

9. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

a passage is provided for generating an air flow not perpendicular to the current forming surface of the workpiece, the air flow flowing at least at the inlet end or at the outlet end of the passage of the contact member; the air flow is generated by means of spraying and/or suction.

10. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

the contact part is detachable.

11. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

a sensor is provided for detecting the position and/or the movement state of the contact member and/or the member connected to the contact member.

12. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

The control circuit is connected with the driving device and controls the position state of the contact part through the driving device; or the control circuit is connected with the sensor and the driving device, and the control circuit controls the position state of the contact part through the driving device according to the detection signal of the sensor.

13. The screeding device for three dimensional printing as claimed in claim 7, wherein:

14. The screeding device for three dimensional printing as claimed in claim 4, wherein:

the contact area is detachable or is connected with other areas of the contact part into a whole and is not detachable; the support body is used for installing the contact part, and the contact part is rotatably and movably connected with the connecting bracket through the support body;

setting a limiting structure, wherein the limiting structure is used for limiting the rotation range of the contact part or limiting the rotation and movement range of the contact part;

15. The screeding device for three-dimensional printing as claimed in claim 14, wherein:

The connecting support is arranged, the connecting support is directly connected or indirectly connected with the contact part through at least 3 telescopic rods, and two ends of each telescopic rod are respectively connected with the connecting support and the contact part through spherical bearings; in the three-dimensional printing process, the contact position of the contact area on the contact part and the workpiece is controlled by the telescopic rod.

16. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

17. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

and a liquid cooling and/or air cooling structure is arranged to cool the contact part.

18. The screeding device for three-dimensional printing as claimed in claim 1, wherein:

in the three-dimensional printing process, the printing raw material in a molten state is not contacted with the inner wall of the channel of the contact part in the process of passing through the channel.

19. A three-dimensional printer comprising a printhead, characterized in that: further comprising a screeding device for three-dimensional printing as claimed in any one of claims 1 to 18, said screeding device being connected to said printhead.

20. The three-dimensional printer according to claim 19, wherein:

21. The three-dimensional printer according to claim 19, wherein: