CN112355325A

CN112355325A - EBSM equipment based on follow-up powder jar

Info

Publication number: CN112355325A
Application number: CN202011044087.4A
Authority: CN
Inventors: 王志翔; 卢秉恒; 王红宇; 韩莉娜; 王磊
Original assignee: National Institute Corp of Additive Manufacturing Xian
Current assignee: National Institute Corp of Additive Manufacturing Xian
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2021-02-12
Anticipated expiration: 2040-09-28
Also published as: CN112355325B

Abstract

The invention belongs to the technical field of 3D printing, and particularly relates to EBSM equipment based on a servo powder cylinder. The technical problems that the traditional EBSM equipment cannot meet the manufacturing requirement of a large component and is low in machining efficiency are solved. The powder spreading and compacting device comprises a vacuum printing chamber, a workbench component, a printing component, a powder feeding component, a powder spreading and compacting component, a vacuum system and a control system; the printing assembly is fixed at the top of the vacuum printing chamber; the printing assembly comprises j groups of printing devices, and the electron guns or the lasers in each group of printing devices are arranged along the same straight line; each group of printing devices form a printing scanning area in the same radius area of the annular table surface of the workbench; the powder spreading and compacting assembly is fixed at the top of the vacuum printing chamber and comprises j powder spreading and compacting devices, and the projections of the powder spreading and compacting devices on the annular table top of the working table are positioned in different radius areas of the annular table top of the working table; utilize workstation cooperation to spread powder compaction device, printing device to realize that many spirals spread powder and print, follow-up powder jar does not have independent shaping time, prints efficiently.

Description

EBSM equipment based on follow-up powder jar

Technical Field

The invention belongs to the technical field of 3D printing, and particularly relates to EBSM equipment based on a servo powder cylinder.

Background

Electron Beam Selective Melting (EBSM) metal additive manufacturing techniques use an electron beam as an energy source to manufacture solid parts by melting metal powder layer by layer in a high vacuum environment. Because the power of the electron beam is high, the material has high energy absorption rate to the electron beam, the finished piece has the characteristics of high density, low oxygen content, low thermal stress, difficult deformation and cracking, high printing efficiency, material utilization rate and the like, and is widely applied in the fields of medical treatment, aerospace and the like. The process comprises the following steps: firstly, spreading a layer of powder on a powder spreading plane; then, the electron beam is selectively melted under the control of a computer according to the information of the cross section profile, the metal powder is melted together under the bombardment of the electron beam and is bonded with the formed part below, and the metal powder is stacked layer by layer until the whole part is completely melted; finally, the excess powder is removed to obtain the desired three-dimensional product.

As shown in fig. 1, the EBSM apparatus generally comprises an electron gun 01, a molding chamber 02, a powder feeding system, a powder spreading system 07, a vacuum system, a cooling system, an electric control system, and the like. The powder feeding system (some devices do not use the system, and only have a powder storage bin) is responsible for feeding the metal powder to the powder spreading system. The powder spreading system spreads the powder on the forming surface 03 on the powder cylinder, and the powder is uniformly spread and scraped. The electron gun generates high energy to locally melt the metal powder on command to form a cross section of the workpiece 04. The vacuum system is responsible for evacuating the forming chamber 02 so that the electron beam can work normally (the electron energy is not attenuated in vacuum). The cooling system protects the transmission components and the like from exceeding normal use temperature. The powder cylinder 05 of the conventional EBSM apparatus is a fixed member, and may be referred to as a fixed powder cylinder. As shown in fig. 1, most of the powder cylinders are rectangular and circular, the rectangular powder cylinder is suitable for horizontal powder spreading and horizontal scanning, and the circular powder cylinder is suitable for spiral powder spreading and spiral printing. The working table 06 can be lifted in the fixed powder cylinder. During printing, the workbench 06 descends layer by layer, powder is spread on the workbench 06 layer by layer, the printing is carried out layer by layer, and the printing is always carried out on the printing surface on the uppermost layer of the powder cylinder. When printing is completed, the whole workpiece and the residual powder are completely settled in the fixed powder cylinder. Finally, the powder bed is required to be lifted to be higher than the fixed powder cylinder, and then the workpiece and the powder are horizontally removed through the removing mechanism. The height of the forming chamber 02 of the apparatus is 2 times greater than that of the workpiece, because the work table 06 is raised after the printing of the workpiece is completed to raise the workpiece above the fixed powder cylinder so as to be moved out of the forming chamber 02 by the removing mechanism.

The apparatus has the following problems:

1) the manufacturing requirements of large components cannot be met. Because the forming chamber (vacuum printing chamber) required by the large-sized part is larger, the equipment cost is higher, the vacuumizing time is longer, the vacuum system is huge, and the moving-out mechanism is huge.

2) Efficiency is also one of the difficulties. The powder spreading and compacting device 51 of the equipment moves horizontally and stops on the left side in a reciprocating mode, then printing is carried out, and powder spreading and printing are carried out discontinuously in a split mode, so that time is wasted.

3) The powder cylinder of the device is fixed, and the powder bed can be lifted in the cylinder. The printing surface is on the top surface of the powder cylinder, one layer of printing is finished, and the powder bed descends by one layer of distance. When all the powder is beaten, the powder bed needs to be lifted out of the powder cylinder and then is horizontally moved out of the vacuum printing chamber through the moving-out mechanism, and at the moment, no shielding object exists around the powder and the part, so that the powder can fall off and pollute the vacuum printing chamber. In addition, the size of the fixed powder cylinder is not changed no matter the size of a workpiece produced each time, so that if the produced workpiece is small, the powder quantity, the powder laying, the powder pressing time, the printing time and the sand cleaning processing time after printing are wasted.

4) The electronic gun for the equipment preheats powder, can meet the requirements for small pieces, and cannot meet the requirement for large-scale preheating for large pieces.

In the prior art, a plurality of electron guns can be adopted to preheat powder, so that the requirement of preheating in a large range is met, but some problems also exist: the guns interfere with each other and the scanning areas of the guns are difficult to connect effectively.

Meanwhile, in the prior art, a device for overcoming the defects caused by the fixed powder cylinder is provided with the dynamic powder cylinder, but in the device, the dynamic powder cylinder needs to be completed by using special independent powder laying and printing components, so that the device is complex in structure and high in cost. And the forming assembly, the laser printing device and the feeding and flattening assembly of the dynamic powder cylinder can move in the three-axis direction, so that the mode is complex in structure and difficult to install and adjust, and the influence factors of printing precision are increased.

Disclosure of Invention

The invention aims to provide the follow-up powder cylinder-based EBSM equipment which is simple in structure and can meet the large-range preheating requirement, so as to solve the technical problems that the traditional EBSM equipment cannot meet the manufacturing requirement of large components and is low in machining efficiency. Meanwhile, the follow-up powder cylinder of the EBSM equipment is formed without independent forming time and a special printing device, and effective connection of scanning areas of all the electron guns is realized by reasonably arranging the areas printed by all the electron guns at the same time, so that beam quality is prevented from being influenced by mutual interference.

The technical scheme of the invention is as follows:

an EBSM device is characterized in that: the powder spreading and compacting device comprises a vacuum printing chamber, a workbench component, a printing component, a powder feeding component, a powder spreading and compacting component, a vacuum system and a control system;

the vacuum printing chamber comprises a box body and a box door positioned on the side wall of the box body;

the workbench component comprises a workbench with an annular workbench surface and a workbench supporting and driving device; an electric furnace is arranged in the workbench; the worktable supporting and driving device can drive the worktable to rotate in a plane where the worktable surface is positioned, namely an XY plane, and can move in the Z direction and move in and out of the vacuum printing chamber through the box door in the X direction;

the printing assembly is fixed at the top of the vacuum printing chamber; the printing assembly comprises j groups of printing devices, and each group of printing devices comprises at least two electron guns or lasers; the electron guns or lasers in each group of printing devices are arranged along the same straight line; each group of printing devices form a printing scanning area in the same radius area of the annular table top of the workbench, and the printing scanning areas of the printing devices are uniformly distributed in the same circumference; j is a positive integer greater than or equal to 2;

the powder feeding assembly is positioned outside the vacuum printing chamber and used for feeding powder into the powder paving compaction assembly;

the powder spreading and compacting assembly is fixed at the top of the vacuum printing chamber, and the powder spreading head is arranged right above the workbench and used for continuously spreading powder in a spiral manner and strickling and compacting the powder on the workbench; the powder spreading and compacting assembly comprises j powder spreading and compacting devices, the projections of the powder spreading and compacting devices on the annular table top of the working table are positioned in different radius areas of the annular table top of the working table, and the projections of the j powder spreading and compacting devices are uniformly distributed in the same circumference;

an included angle is formed between the projection of each powder paving and compacting device on the annular table top of the workbench and the printing scanning area of each group of printing devices;

the vacuum system is used for vacuumizing the vacuum printing chamber;

the control system is used for controlling the workbench assembly, the printing assembly, the powder feeding assembly, the powder paving and compacting assembly and the vacuum system to work according to a set time sequence.

Further, for ease of control, j equals 2;

the printing scanning areas of the two groups of printing devices are respectively positioned in two radius areas with the same diameter on the annular table surface of the workbench;

the projections of the two powder paving and compacting devices on the annular table top of the working table are respectively positioned in two radius areas with the same diameter of the annular table top of the working table;

the projection of the two powder spreading compaction devices on the annular table top of the workbench is vertical to the printing scanning area of the printing device on the annular table top of the workbench.

Further, in order to improve the efficiency, the annular table top of the workbench comprises an inner annular area and an outer annular area;

each group of printing devices comprises two electron guns or lasers, and the printing scanning areas of the two electron guns or lasers in each group of printing devices are respectively positioned in the inner circular ring area and the outer circular ring area.

Further, the powder feeding assembly comprises at least j powder feeding devices, and each powder feeding device is used for feeding powder into one powder paving compaction device;

the powder feeding device comprises a powder feeding shell, a plurality of groups of powder wheel assemblies and a plurality of groups of driving assemblies, wherein the length direction of the powder feeding shell is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction;

a powder feeding cavity is arranged in the powder feeding shell, at least one powder inlet is formed in the top of the powder feeding shell and communicated with the powder feeding cavity, a plurality of powder discharging channels communicated with the powder feeding cavity are formed in the bottom of the powder feeding shell along the X direction, and the number of the powder discharging channels is the same as that of the powder wheel assemblies and the driving assemblies;

the powder wheel assembly comprises a transmission shaft, a powder feeding wheel and two side leakage prevention wheels, the transmission shaft is arranged in the powder outlet channel, and the axis of the transmission shaft is parallel to the Y direction; the powder feeding wheel and the side leakage prevention wheel are sleeved on the transmission shaft, the powder feeding wheel is positioned between the two side leakage prevention wheels, a plurality of wheel grooves of the powder feeding wheel are uniformly distributed along the circumferential direction of the powder feeding wheel, and a plurality of annular wheel grooves of the side leakage prevention wheel are arranged along the axial direction of the side leakage prevention wheel and are arranged at 90 degrees with the wheel grooves of the powder feeding wheel;

the driving assembly is arranged outside the powder feeding shell, and the output end of the driving assembly is connected with the transmission shaft and used for driving the transmission shaft to rotate;

the powder outlet channel comprises a first channel, a second channel and a third channel which are sequentially communicated along the Z direction; the first channel is a trapezoidal channel, the large end of the first channel is communicated with the powder feeding cavity, the small end of the first channel is communicated with the second channel, the second channel is obliquely arranged with the XY plane, the central line of the second channel and the central line of the first channel are arranged at a certain angle when seen from the XZ plane, and the central line of the third channel is parallel to the central line of the first channel;

the powder wheel subassembly sets up in the second passageway, and send the clearance of powder wheel and second passageway to equal to the maximum size of powder granule for the powder granule can pass through smoothly.

Furthermore, the central line of the second channel and the central line of the first channel are arranged at an angle of 100-160 degrees; the width of the small end of the first channel is the same as that of the powder feeding wheel, and the width of the third channel is the same as the sum of the widths of the powder feeding wheel and the wheel grooves of the two side leakage prevention wheels.

Furthermore, the powder spreading and compacting device comprises a powder dropping box and a plurality of groups of powder scraping assemblies which are all arranged at the bottom of the powder dropping box; setting the length direction of the powder dropping box as the X direction, the width direction as the Y direction and the height direction as the Z direction;

a plurality of powder falling cavities which are distributed along the X direction are arranged in the powder falling box, and a plurality of scattering plates are arranged in the powder falling cavities and used for scattering powder falling into the powder falling cavities; the top of the powder dropping box is provided with a plurality of powder inlets communicated with the powder dropping cavity, and the bottom of the powder dropping box is provided with a plurality of powder outlets communicated with the powder dropping cavity;

the powder scraping component comprises a soft scraping plate, a hard scraping plate and a compacting plate, and the powder outlet, the soft scraping plate, the hard scraping plate and the compacting plate are sequentially arranged along the Y direction;

the soft scraping plate is of a comb-tooth-shaped structure and comprises a plurality of scraping strips arranged along the X direction;

the powder scraping end face of the hard scraper is equal to the powder scraping end face of the soft scraper in the Z direction;

the powder-scraping end face of the hard scraper is lower than the powder-scraping end face of the compaction plate in the Z direction.

The scattering plates are arranged on a front side plate and a rear side plate which are opposite to each other in the Y direction of the powder falling box, and the scattering plates arranged on the front side plate and the scattering plates arranged on the rear side plate are arranged in a staggered manner in the X direction and the Z direction;

each powder inlet in the powder paving compacting device is respectively communicated with one powder outlet channel in the powder feeding device.

Furthermore, the scattering plate is a triangular flat plate, and the inclined side edge of the triangular flat plate is used for scattering the powder falling into the powder falling cavity;

the powder pressing end surface of the compacting plate is an arc surface;

and a plurality of partition plates are arranged between the hard scraper plate and the compacting plate.

Furthermore, the workbench supporting and driving device comprises a rotary driving mechanism, a lifting mechanism and a horizontal moving mechanism;

the rotary driving mechanism can drive the workbench to rotate in an XY plane;

the lifting mechanism can drive the workbench to move along the Z direction;

the horizontal moving mechanism can drive the workbench to move along the X direction, so that the workbench can move in and out of the vacuum printing chamber.

Further, the EBSM apparatus also includes an auxiliary heating and cooling system;

the auxiliary heating and cooling system comprises a preheating unit, a demagnetization unit and a water cooling unit;

the degaussing units are at least one group, each group of degaussing units comprises two degaussing conductive wires which are oppositely arranged in the vacuum printing chamber and are used for weakening the magnetic field intensity of the printing area;

the preheating unit comprises a top heat-insulation plate, a heat-insulation box body and a heating device;

the heat insulation box body is arranged in the vacuum printing chamber, a heat insulation layer is arranged in the heat insulation box body, and at least two atmosphere channels are arranged at the top of the heat insulation box body and used for inflow and outflow of external atmosphere gas;

the top heat insulation plate is arranged above the heat insulation box body and forms a heat insulation cavity together with the heat insulation box body, and meanwhile, an electron beam or laser beam channel and a powder falling channel which can enable an electron beam or a laser beam to pass are arranged on the top heat insulation plate;

during printing, the workbench is positioned in the heat-insulating cavity;

the heating device is arranged in the heat-preserving cavity along the Y direction and is used for heating the printing area;

the water cooling unit is arranged on the side wall of the heat preservation box body along the X direction and used for cooling the heat preservation box body.

Further, the EBSM equipment also comprises a dynamic shape trimming device which is used for trimming the inner circular wall and the outer circular wall of the follow-up powder cylinder formed in the printing process.

Further, the control system comprises a CNC system, a PLC, a server, an industrial personal computer and a printing device control cabinet;

the CNC system is a 3-axis double-gantry linkage interpolation motion control system and is used for performing servo control on motor shafts of the rotation driving mechanism, the lifting mechanism and the horizontal moving mechanism;

the PLC controls the powder feeding assembly, the powder spreading compaction assembly, the dynamic shaping device, the vacuum system, the electric furnace and the door of the vacuum printing chamber; data transmission and instruction interaction are carried out through a communication bus and a CNC system;

the server carries out three-dimensional graph input, analysis, processing and process optimization on the workpiece to be formed and the follow-up powder cylinder; performing spiral slicing, determining a scanning path and parameters, processing the scanning path and the parameters into various instruction codes and related parameters, and generating a printing component control program;

the industrial personal computer monitors the C-axis rotation angle of the workbench, samples and analyzes the C-axis rotation angle, acquires the exact C-axis position, compares the exact C-axis position with the C-axis theoretical position corresponding to the currently running electron gun signal generation control program segment, calculates the error between the exact C-axis position and the C-axis theoretical position, and corrects the current electron gun signal generation control program segment; at the same time, executing the control program of the printing component;

and the printing device control cabinet receives a control program sent by the industrial personal computer, and performs cooperative control on j groups of printing devices and real-time matching with the rotating position of the workbench.

The invention has the beneficial effects that:

1. the manufacturing requirements of large components can be met and high-efficiency printing can be realized;

the multi-spiral powder spreading printing is realized by using the workbench supporting and driving device to cooperate with j powder spreading compaction devices and the printing device. The workbench descends while rotating, the j powder spreading and printing are simultaneously carried out on the powder spreading printing workpiece and the follow-up powder cylinder, the follow-up powder cylinder has no independent forming time, and the printing efficiency is high.

After printing is finished, the workbench (comprising a formed workpiece and a follow-up powder cylinder) is driven by the workbench supporting and driving device to move out of the vacuum printing chamber. The vacuum printing chamber does not need to leave a rising space (height space) for the formed workpiece to move out of the working chamber, does not need a space (horizontal space) of the powder recovery cylinder, and saves the size of equipment. Because the space of the vacuum printing chamber 1 is saved, the vacuumizing time is saved, and a vacuum system does not need to be large. Therefore, the manufacturing cost of the equipment can be greatly reduced, and the manufacturing requirement of large components can be met.

2. The structure is simple, and the installation and adjustment are convenient;

the powder spreading and compacting device and the printing device are fixed on the upper part of the vacuum printing chamber box body. And the follow-up powder cylinder and the formed workpiece share the powder spreading and compacting device and the printing device, so that the structure is simple and the installation and adjustment are convenient. Meanwhile, the powder spreading and compacting device and the printing device do not need to be moved, so that factors influencing powder spreading and printing precision are reduced.

3. The printing device is reasonable in arrangement and high in beam quality;

the invention comprises a plurality of groups of printing devices, wherein each group of printing devices comprises at least two electron guns or lasers; the electron guns or lasers in each group of printing devices are arranged along the same straight line; each group of printing devices form a printing scanning area in the same radius area of the annular table top of the workbench, and the printing scanning areas of the printing devices are uniformly distributed along the same circumference; through the arrangement and the reasonable printing sequence, the areas printed by the electron guns or the lasers simultaneously are effectively connected, the thermal deformation is reduced, and the mutual interference between the adjacent electron guns is reduced.

4. The pollution is little, and the waste is little;

the invention uses the follow-up powder cylinder, can reduce the pollution of the vacuum printing chamber: in the process of printing and pulling out the working chamber after beating, the powder is tightly surrounded by the follow-up powder cylinder, so that the powder is prevented from scattering to the working chamber, and the pollution of the vacuum printing chamber 1 is caused. The size of the follow-up powder cylinder is determined according to the size of a printed piece each time, and the follow-up powder cylinder is only a little larger than a workpiece, so that powder is not wasted.

5. The powder feeding assembly can realize active automatic powder feeding, multi-motor multi-point driving is realized, the powder feeding efficiency is improved, the powder feeding is automatic, and continuous high-efficiency production can be realized. By controlling the rotating speed of each motor, the requirements of different powder feeding amounts in different areas can be met, and then the requirement of uniform powder spreading thickness on a rotary worktable is met, so that high-precision forming manufacturing is completed.

6. According to the powder paving and compacting device, the soft scraper, the hard scraper and the compacting plate are sequentially arranged at the powder outlet, the powder paving quality is ensured by a powder scraping and compacting mode, the compacting effect is good, and the quality of a formed part is increased; meanwhile, the powder spreading device can work in cooperation with a rotary workbench, continuous spreading, scraping and compacting of powder are achieved, and working efficiency is improved;

and the soft scraper is arranged in front of the hard scraper of the powder spreading device, and pre-pushes the powder uniformly by the soft scraper, so that the stress of the hard scraper is reduced, the soft scraper pushes the redundant powder to the side of the rotary powder bed, and finally the powder bed is pushed out, so that the problem that the powder can overflow is avoided.

7. The auxiliary heating system and the cooling system are used for heating and insulating the forming area by the large EBSM equipment based on the auxiliary preheating system through the heating device, so that the forming area meets the temperature requirement of a printing process, the flowability of powder is reduced, and the powder is not dispersed and is more compact in the printing process; meanwhile, the heating area is insulated through the top insulation board and the insulation box body, so that the requirement of the temperature of the forming area is met, and the energy input is reduced.

8. The control system can realize the orderly cooperative control of a plurality of printing devices;

the control system comprises a CNC, a PLC, an industrial personal computer and a server, can solve the problem that the conventional large-size complex piece forming electronic gun controller cannot perform cooperative control on more than 3-axis control systems, realizes cooperative work of a plurality of groups of printing devices, and ensures the running precision and stability of each axis of the equipment through the CNC system; through PLC, the time sequence of systems such as a temperature control system, a vacuum system and a heating system of the equipment is ensured to be uniform.

9. The control system can plan the printing path of the formed workpiece in a server cloud computing mode, does not occupy the computing resource overhead in the whole equipment processing time, and can effectively reduce the equipment cost; the server cloud printing program computing mode used by the control system can be shared by a plurality of large-size complex electron beam metal additive manufacturing (EBSM) devices, computing resources can be fully utilized, and information sharing and database establishment are achieved.

10. The spiral slicing is simple and easy to implement, and high-efficiency production can be realized;

according to the invention, a spiral step type slicing mode is adopted, a three-dimensional graph of a follow-up powder cylinder and a workpiece to be formed are combined together and uniformly divided into n fan-shaped areas on an XOY plane by taking a C axis and a Z axis as parameters, the angle alpha of each fan-shaped area is 360/n, and the Z value difference of adjacent fan-shaped areas is h; the problem that the printing surface (powder spreading surface) is not perpendicular to the Z axis and the conventional slicing software cannot slice is solved. The spiral slicing method is matched with continuous multi-spiral powder laying and multi-spiral printing, and high-efficiency production can be realized.

11. The shape of each slice area of the method is a sector, the inner diameter and the outer diameter of the sector are determined according to the size of a printed workpiece each time, and the included angle alpha of the sector is determined by the precision required by the printed workpiece and the equipment operation parameters. The method simplifies continuous spiral surface (forming an included angle-helix angle with the XOY surface) printing into horizontal surface printing. Each horizontal printing area is a sector, and the height difference of each sector is H/jn (H is the thread pitch, n is the number of sectors per week, and n is 360/alpha). In the printing surface of each horizontal sector area, the printing surface is divided into a plurality of small sector areas which are arranged along the radial direction, and different electron guns which are arranged along the radial direction are controlled to carry out accurate and ordered partition scanning and forming on the corresponding areas. In order to avoid the problem that the beam quality is influenced by mutual interference of adjacent electron beam light spots working at the same time due to too close distance, the positions of the two adjacent electron guns for printing the light spots at the same time are controlled to be larger than a set value, the seamless connection of the printing ranges of the two adjacent electron guns can be realized, and the local quality and the overall quality of a printing area are ensured.

Drawings

FIG. 1 is a schematic structural diagram of a prior art EBSM device;

the reference numbers in the figures are: 01-electron gun, 02-forming chamber, 03-forming surface, 04-workpiece, 05-powder cylinder, 06-workbench and 07-powder spreading system;

FIG. 2 is a schematic structural diagram of an EBSM device according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a worktable assembly in the EBSM apparatus according to the embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a worktable assembly in the EBSM apparatus according to the embodiment of the present invention, wherein the worktable is at an upper limit position;

FIG. 5 is a schematic structural diagram of an EBSM apparatus, a print workpiece, and a powder cylinder during printing;

FIG. 6 is an enlarged view of a portion of FIG. 5;

FIG. 7 is a schematic view of a powder feed assembly;

FIG. 8 is a cross-sectional view A-A of FIG. 7;

FIG. 9 is a schematic structural view of a powder outlet passage in the powder feeding assembly;

FIG. 10 is a schematic view of the construction of the powder wheel assembly of the powder feeding assembly;

FIG. 11a is a diagram showing the relative positions of the servo powder cylinder, the printing workpiece, the powder spreading and compacting device, the printing scanning area and the workbench; the printing workpiece is a large complex annular part;

FIG. 11b is a top view of FIG. 11 a;

FIG. 12a is a diagram showing the relative positions of the servo powder cylinder, the printing workpiece, the powder spreading and compacting device, the printing scanning area and the workbench; the printing workpiece is a complex annular part;

FIG. 12b is a diagram showing the relative positions of the servo powder cylinder, the printing workpiece, the powder spreading and compacting device, the printing and scanning area and the workbench; printing a plurality of complex workpieces of the same or different types;

FIG. 13 is a schematic view of the construction of the breading compaction apparatus;

FIG. 14 is a cross-sectional view A-A of FIG. 13;

FIG. 15 is an enlarged view of a portion of FIG. 14;

FIG. 16 is a schematic view of the construction of a soft flight;

FIG. 17a is a schematic view of the installation of the degaussing conductor wire;

FIG. 17b is a schematic structural view of the preheating unit;

FIG. 18a is a schematic view of a printed workpiece structure;

FIG. 18b is a schematic structural view of a servo powder cylinder;

FIG. 19 is a schematic view showing the double helix growth of the follower powder cylinder during printing;

FIG. 20 is a schematic view of the lowest limit position of the worktable outside the vacuum printing chamber box;

FIG. 21a is a schematic powder laying view of a single set of powder laying compaction apparatus with the table rotated one revolution;

FIG. 21b is a partial enlarged view of FIG. 21 a;

FIG. 22 is a schematic powder laying view of a double powder laying compaction apparatus with one rotation of the table;

fig. 23 is a schematic diagram of the powder spreading and electron gun positions for realizing 3-screw printing by three sets of powder spreading and compacting devices when the workbench rotates for one circle;

FIG. 24 is a schematic view of each sector in zones (when each set of printing devices includes 2 electron guns);

FIG. 25 is a schematic view of a section of each sector (when each set of printing devices includes 3 electron guns);

FIG. 26 includes schematic illustrations of an arrangement of two sets of printing devices, each set including two electron guns;

FIG. 27 control system components.

The reference numbers in the figures are:

1-a vacuum printing chamber, 2-a workbench component, 3-a printing component, 4-a powder feeding component, 5-a powder paving and compacting component and 6-a vacuum system;

11-box body, 12-box door;

15-a preheating unit, 151-a top heat-insulation plate, 152-a heat-insulation box body, 154-a heat-insulation layer, 155-a heat-insulation screen, 156-an atmosphere channel, 157-an electron beam or laser beam channel, 158-a powder falling channel, 16-a demagnetization unit and 161-a demagnetization conducting wire;

21-workbench, 22-workbench support driving device, 221-upright post, 222-sliding table;

31-printing means, 311-electron gun or laser, 32-print scan zone, 33-electron beam;

41-powder feeding shell, 411-powder feeding cavity, 412-powder inlet, 413-powder outlet channel, 4131-first channel, 4132-second channel, 4133-third channel, 42-powder wheel component, 421-transmission shaft, 422-powder feeding wheel, 423-side leakage prevention wheel and 43-driving component;

51-a powder spreading compaction device;

511-powder dropping box, 5111-powder dropping cavity, 5112-scattering plate, 5113-powder inlet, 5114-powder outlet, 512-powder scraping component, 5121-soft scraper, 51211-scraper bar, 51212-powder scraping end face, 5122-hard scraper and 5123-compacting plate;

7-base plate, 71-inner circular wall, 72-outer circular wall;

8-workpiece, 9-metal powder.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

As shown in fig. 2, the EBSM apparatus of this embodiment mainly includes: printing assembly 3, vacuum printing room 1, vacuum system 6, auxiliary heating and cooling system, control system, powder feeding assembly 4, powder paving and compacting assembly 5 and workstation assembly 2.

The vacuum printing chamber 1 is used for providing a vacuum printing environment and meeting the use requirements of electron beams or laser beams, and comprises a box body 11 and a box door 12, wherein the box door 12 is driven by a motor to realize push-pull opening and closing along an upper sliding rail and is locked by an air cylinder. The box body 11 and the box door 12 are effectively sealed, and the vacuumizing effect is ensured.

The vacuum system 6 is composed of parts such as a molecular pump, a roots pump, a screw pump, a valve and the like, and completes the vacuumizing task of the vacuum printing chamber 1.

Referring to fig. 2, 3 and 4, the table assembly 2 includes a table 21 and a table supporting and driving device 22, and the table supporting and driving device 22 includes a column 221, a sliding table 222, and the like in this embodiment. Two upright columns 221 are fixed on the sliding table 222 through bolts, and an elevating mechanism is arranged on the upright columns 221, and the working table 21 can be elevated along the upright columns 221 under the driving of the elevating mechanism. The lifting mechanism includes a lifting motor, a lead screw, a guide rail on the column 221, and the like. The slide table 222 is provided with a horizontal moving mechanism, and the table 21 can be moved in the horizontal direction by the driving of the horizontal moving mechanism, so that the table 21 can be moved into and out of the vacuum printing chamber 1. The horizontal movement mechanism includes a roller, a guide rail, a screw, and the like, which are disposed under the slide table 222. The lifting mechanism and the horizontal moving mechanism are provided with linear grating rulers for measuring and positioning. The table-board of workstation 21 is the ring shape, and excircle diameter 1500mm, interior circle diameter 350 mm. A rotary driving mechanism is arranged below the workbench 21, and the rotary driving mechanism comprises a rotary motor, a rotary bearing, a c-axis circular grating ruler and the like and drives the workbench 21 to rotate. An electric furnace is arranged in the workbench 21 and plays a role in preheating the powder.

As shown in fig. 5 and 6, the printing assembly 3 is composed of a plurality of sets of printing devices 31, each set of printing devices 31 including at least two electron guns or lasers 311, each electron gun including a cathode, an anode and a focus scanning system. The print head is located in the vacuum printing chamber 1. The electron guns or lasers 311 in each set of printing devices 31 are arranged along the same straight line; each group of printing devices 31 form a printing scanning area 32 in the same radius area of the annular table top of the workbench, and the printing scanning areas 32 of the printing devices 31 are uniformly distributed along the same circumference.

As can be seen from fig. 5 and 6, the present embodiment includes two sets of printing devices 31, each set of printing device 31 includes two electron guns fixed on the top of the vacuum printing chamber 1, the printing device 31 generates an electron beam 33, and forms a printing scanning area 32 on the annular table of the worktable 21; the two electron guns in each set of printing devices 31 are arranged along the same straight line, a printing scanning area 32 is formed in the same radius area of the annular table top of the workbench, and the printing scanning areas 32 of the two sets of printing devices 31 are located in the same diameter of the annular table top of the workbench. The two electron guns in each set of printing devices 31 are respectively used for printing the inner circular ring area and the outer circular ring area of the annular table board. The electron guns work in coordination to avoid mutual interference.

The powder feeding component 4 is arranged at the upper part outside the box body 11 and is not in a vacuum environment (different from the prior art), so that the working environment is good and the manufacturing cost is saved. And saves space in the vacuum printing chamber 1. The function of the device is to quantitatively and accurately feed the powder in the powder bin into the powder spreading and compacting device 51. The powder feeding wheels are respectively driven by the motors to meet the powder feeding requirements of different quantities at multiple positions, the use of powder is reduced, and the time is saved.

As shown in fig. 7 and 8, the powder feeding assembly 4 includes at least j powder feeding devices, the number of which is the same as that of the powder laying compaction devices 51, each of which is used for feeding powder into one of the powder laying compaction devices 51; each powder feeding device comprises a powder feeding shell 41, a plurality of powder wheel assemblies 42 and a plurality of driving assemblies 43, in order to describe the structure of the powder feeding device more conveniently, the length direction of the powder feeding shell 41 is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction. The powder feeding housing 41 is provided with a powder feeding cavity 411 therein, the top thereof is provided with at least one powder inlet 412, the powder inlet 412 is communicated with the powder feeding cavity 411, the bottom thereof is provided with a plurality of powder outlet channels 413 communicated with the powder feeding cavity 411 along the X direction, and the number of the powder outlet channels 413 is the same as that of the powder wheel assembly 42 and the driving assembly 43. Multiple sets of the powder wheel assemblies 42 are arranged in the powder outlet passage 413, and the driving assemblies 43 are used for driving the powder wheel assemblies 42.

As shown in fig. 9, the powder discharging passage 413 may be configured to include a first passage 4131, a second passage 4132, and a third passage 4133, which are sequentially communicated from top to bottom (i.e., along the Z direction); the first channel 4131 is a trapezoidal channel, the large end of which is communicated with the powder feeding cavity 411, the small end of which is communicated with the second channel 4132, the second channel 4132 is obliquely arranged along the horizontal direction (i.e. obliquely arranged with the XY plane), the central line of the second channel 4132 is arranged at a certain angle with the central line of the first channel 4131 when viewed from the XZ plane, and the central line of the third channel 4133 is parallel with the central line of the first channel 4131. At this time, an angle β between a center line of the second channel 4132 and a center line of the first channel 4131 is 100 to 160 degrees, and may be 145 degrees. A powder feeding wheel is arranged in the second channel 4132, the powder feeding wheel is equivalent to a control valve for controlling the powder flow, the powder feeding wheel rotates by 45 degrees to bring the powder from the first channel 4131 to the third channel 4133, and the powder passing amount is calibrated through the rotation speed of the powder feeding wheel.

As shown in fig. 7 and 10, the powder wheel assembly 42 of the present invention is disposed in the powder outlet passage 413, and includes a transmission shaft 421, a powder feeding wheel 422 and two side leakage prevention wheels 423, wherein the transmission shaft 21 is disposed in the second passage 132 of the powder outlet passage 413, and the axis thereof is parallel to the Y direction; powder feeding wheel 422 and side leakage prevention wheel 423 are sleeved on transmission shaft 421, powder feeding wheel 422 is located between two side leakage prevention wheels 423, a plurality of wheel grooves of powder feeding wheel 422 are uniformly distributed along the circumferential direction of powder feeding wheel 422, a plurality of annular wheel grooves of side leakage prevention wheel 423 are arranged along the axial direction of side leakage prevention wheel 423, and the wheel grooves of powder feeding wheel 422 are arranged at 90 degrees. The powder feeding wheel 422 is similar to a gear in structure, powder is quantitatively transferred into the lower straight channel through a gear groove on the powder feeding wheel, the powder discharging amount is controlled by the rotating speed of the powder feeding wheel 422, each powder feeding wheel 422 is independently driven by one motor, and the speed of the motor is adjustable and controllable, so that the flexible control of the powder amount is realized, and the accurate powder feeding can be realized.

As shown in fig. 10, the transmission shaft 421 of the present invention is provided with the side leakage prevention wheels 423, and the side leakage prevention wheels 423 are disposed at two sides of the powder feeding wheel 422, so as to prevent the powder particles from leaking from the axial side, so that the powder feeding amount of the powder paving device can be accurately controlled, and the purpose of accurately controlling the powder feeding amount can be achieved. Meanwhile, the width of the first channel 4131 is the same as that of the powder feeding wheel 422, the width of the third channel 4133 is the same as the sum of the widths of the wheel grooves of the powder feeding wheel 422 and the two side leakage prevention wheels 423, namely the width of the inner cavity of the shell at the upper part of the powder wheel cavity is the same as that of the powder feeding wheel 422, and the width of the inner cavity at the lower part of the powder wheel cavity contains the side leakage groove, so that the side leakage powder particles have a dredging space, and the powder particles are prevented from being extruded into the side gap to cause the mechanism to be blocked.

As shown in fig. 7, the driving assembly 43 is disposed outside the powder feeding housing 41, and an output end thereof is connected to the transmission shaft 421 for driving the transmission shaft 421 to rotate. In order to save the installation space and make the powder feeding device compact, a plurality of sets of driving assemblies 43 may be alternately arranged on both sides of the powder feeding housing 41. At this time, the powder wheel assembly 42 is specifically disposed on the powder feeding housing 41 by the following structure, the driving device adopts a servo motor 431, the transmission shaft 421 is connected with a driving shaft of the servo motor 431 through a coupling 432, and the transmission shaft 421 is disposed on the powder feeding housing 41 through a bearing assembly. The bearing assembly mainly comprises a bearing, a spacer bush, a bearing seat, an end cover, a sealing ring and the like, and ensures power transmission between the driving motor and the transmission shaft 421. Because the powder falling amount of the powder in the radial direction is different, and the powder falling amount of each section is determined by the rotating speed of the servo motor 431, the rotating speed of each servo motor 431 is respectively controlled in the printing process, so that when a small part is printed, the powder feeding motor in the large diameter position can be controlled to stop rotating, the powder feeding is stopped at the excircle position, the powder spreading is directly reduced in the radial direction, and the powder waste is avoided.

In this embodiment, the top of the powder feeding housing 41 is provided with two powder inlets 412, the bottom of the powder feeding housing is provided with 10 powder outlet channels 413, and the upper space of the inner cavity of the housing is large, so as to facilitate smooth powder entering and fully receive and store the powder entering from the two powder inlets 412. The powder wheel cavity (i.e. the second channel 4132) of the powder outlet channel 413 is internally provided with a powder wheel assembly 42, and a through outlet is arranged below the powder wheel cavity. The gap between the powder feeding wheel 422 and the powder wheel cavity is specific, that is, the gap between the powder feeding wheel 422 and the second channel 4132 is the maximum size of the powder particles, so as to meet the requirement that the powder particles can not be blocked and can smoothly pass through.

The powder spreading and compacting assembly 5 comprises j powder spreading and compacting devices 51 which are fixed at the top of the vacuum printing chamber 1, and a powder spreading head is positioned in the vacuum printing chamber 1 and is arranged right above the workbench 21; the projection of each powder paving compacting device 51 on the annular table top of the workbench is positioned in different radius areas of the annular table top of the workbench, and the projections of the powder paving compacting devices 51 on the annular table top of the workbench are uniformly distributed along the same circumference for continuously spreading and strickling and compacting powder on the workbench 21 in a spiral manner; the projection of each powder spreading and compacting device 51 on the annular table top of the workbench and the printing scanning area 32 of each group of printing devices 31 form an included angle, and the included angles can be uniformly distributed on the table top of the workbench 21 at intervals.

As can be seen from fig. 5 and 6, the powder spreading and compacting assembly 5 of the present embodiment includes two powder spreading and compacting devices 51 fixed on the top of the vacuum printing chamber 1, and the powder spreading head is located in the vacuum printing chamber 1 and is positioned right above the workbench 21; the projection of each powder paving compacting device 51 on the annular table top of the working table is positioned in different radius areas of the annular table top of the working table, and the projections of the two powder paving compacting devices 51 on the annular table top of the working table are positioned in the same diameter of the annular table top of the working table and are perpendicular to the printing scanning areas 32 of each group of printing devices 31; for continuously spreading and screeding the powder in a spiral fashion onto the table 21.

As can also be seen from fig. 11a, 11b, 12a and 12b, the relative positions of the powder spreading and compacting device 51, the print scanning area 32 and the table 21 (the position of the substrate can be understood as the position of the table top because the substrate 7 is placed on the table top) are shown in this embodiment. Two powder spreading compaction devices 51 are located above the rotary table 21, and the projections of the two powder spreading compaction devices on the table surface of the rotary table are distributed on two radiuses of a diameter (x axis) and have a certain distance t from the x axis, and the distance positions are in relation to the rotating direction of the rotary table 21, as shown in fig. 11a, 11b, 12a and 12 b. The two print scanning areas 32 are located on a radius (y-axis) perpendicular to the projection of the dusting compacting device 51, and are arranged with central symmetry.

As shown in fig. 13 and 14, the powder spreading and compacting device 51 includes a powder dropping box 511 and powder scraping assemblies 512, wherein the powder scraping assemblies 512 are in multiple groups and are all fixed at the bottom of the powder dropping box 511 by bolts; setting the length direction of the powder dropping box 511 as the X direction, the width direction as the Y direction, and the height direction as the Z direction; a plurality of powder falling cavities 5111 arranged along the X direction are arranged in the powder falling box 511, and a plurality of scattering plates 5112 are arranged in each powder falling cavity 5111 and are used for scattering powder falling into the powder falling cavities 5111; the top of the powder dropping box 511 is provided with a plurality of powder inlets 5113 communicated with the powder dropping cavity 5111, and the bottom is provided with powder outlets 5114 communicated with the powder dropping cavity 5111 and arranged in a row along the x direction; each powder inlet 5113 is respectively communicated with one powder outlet channel 413 in the powder feeding device to receive metal powder fed by the powder inlet 5113, and the metal powder with accurate amount falls from the powder inlet 5113, is uniformly dispersed by the impact of each scattering plate 5112, and then uniformly falls from the powder outlet to the annular workbench.

In this embodiment, the scattering plates 5112 are disposed on the front side plate and the rear side plate of the powder box 511 opposite to each other in the Y direction, and the plurality of scattering plates 5112 disposed on the front side plate and the plurality of scattering plates 5112 disposed on the rear side plate are arranged in a staggered manner in both the X direction and the Z direction, so that no dead angle is scattered for the falling powder, and the metal powder is scattered uniformly. The scattering plate 5112 may be a triangular flat plate, and the inclined side of the triangular flat plate is used to scatter the powder falling into the powder falling chamber 5111.

As shown in fig. 14, 15 and 16, the powder scraping assembly 512 of the present invention includes a soft scraper 5121, a hard scraper 5122 and a compacting plate 5123, and the powder outlet 5114, the soft scraper 5121, the hard scraper 5122 and the compacting plate 5123 are sequentially arranged in the Y direction; the soft scraper 5121 has a comb-shaped structure, and includes a plurality of scrapers 51211 arranged along the X direction; the powder scraping end face of the hard scraper 5122 is equal to the powder scraping end face 51212 of the soft scraper 5121 in height in the Z-axis direction; the powder-scraping end face 51231 of the compacting plate 5123 is lower than the powder-scraping end face of the hard scraper 5122 in the Z-axis direction, i.e., the lowest points of the soft scraper 5121 and the hard scraper 5122 are at the same height, and the difference between the heights of the hard scraper 5122 and the lowest point of the compacting plate 5123 is the powder compacting amount. A plurality of partition plates 5124 are further provided between the hard blade 5122 and the compacting plate 5123 such that the soft blade 5121, the hard blade 5122, and the compacting plate 5123 are parallel to and spaced apart from each other.

As shown in fig. 14, the soft scraper 5121 is similar to a plate-type comb in structure, the plate thickness is 0.1mm, the width of the comb teeth is 0.85mm, the space between the comb teeth is 0.15mm, and the soft scraper 5121 itself is not damaged because the soft scraper has the function of pushing powder uniformly in advance, and when the powder resistance is large, individual comb teeth can be bent to release pressure and then rebound to the original shape. After the soft scraper 5121 is pre-scraped, the stress of the hard scraper 5122 is relatively reduced, and the hard scraper 5122 acts to push the powder evenly. The compacting plate 5123 only plays a role of compacting powder on the x-axis (i.e., on the radius of the circular ring) but not playing a role of pushing powder, the powder compacting end face 51231 of the compacting plate 5123 can be set to be an arc-shaped face, and the arc-shaped face is designed to have a certain pressing angle and the pressing angle is in smooth transition. The size of the arc-shaped surface is ensured, and the fixing difference between the highest point and the lowest point is larger than the diameter of the powder particles, so that the particles are not scraped.

The powder feeding assembly 4, the powder paving compacting assembly 5 and the printing assembly 3 are all installed and fixed on the box body 11 of the vacuum printing room 1, and are adjusted once during installation, and do not move any more during working, so that various accumulated errors caused by the movable powder feeding, powder paving and compacting device 51 and the printing device 31 in the prior art can be avoided.

The auxiliary heating system is responsible for initially preheating the powder bed, solves the problem that the electron beam 33 of the large-size part cannot be quickly preheated, supplements the temperature in the printing process, reduces the thermal stress and improves the printing quality. The heat preservation device can ensure that the heat of the working area is not dissipated. The cooling system is responsible for cooling the precision parts without being affected by heat of the heat zone. The cooling of the box body 11 is carried out, so that the box body is not deformed, and the working precision of the powder feeding device, the powder laying compaction device 51, the printing device 31 and the like which are arranged on the box body 11 is ensured.

As shown in fig. 17a and 17b, the auxiliary heating and cooling system includes a preheating unit 15, a demagnetization unit 16, and a water cooling unit; the degaussing units 16 are at least one group, and each group of degaussing units 16 comprises two degaussing conductive wires 161 which are oppositely arranged in the vacuum printing chamber 1 and are used for weakening the magnetic field intensity of the printing area; the preheating unit 15 comprises a top heat-insulation plate 151, a heat-insulation box body 152 and a heating device; the heat insulation box body 152 is arranged in the vacuum printing chamber 1, the heat insulation layer 154 is arranged in the heat insulation box body, and at least two atmosphere channels 156 are arranged at the top of the heat insulation box body and used for inflow and outflow of external atmosphere gas; the top heat-insulation plate 151 is arranged above the heat-insulation box body 152, forms a heat-insulation cavity with the heat-insulation box body 152, and is provided with an electron beam or laser beam channel 157 and a powder falling channel 158 which can enable an electron beam or laser beam to pass through; during printing, the workbench 21 is positioned in the heat insulation cavity; the heating device is arranged in the heat-preserving cavity along the Y direction and is used for heating the printing area; the water cooling unit is disposed on a side wall of the heat-insulating box 152 in the X direction, and is configured to cool the heat-insulating box 152.

The control system is responsible for coordinated motion control among the various components. And coordinating the motion time sequence between the printing device 31 and the workbench 21, and scheduling the control time sequences of the vacuum printing chamber 1, the powder feeding assembly 4, the powder paving and compacting assembly 5, the vacuum system 6 and the cooling system to ensure that all processes are reliably and orderly carried out.

The follow-up toner cylinder in the present invention is not a fixed member of the apparatus but is gradually formed on the substrate 7 along with the work printed during the printing of the work. See fig. 5 and 6. In printing, the metal powder is fixed on the powder bed, so that the powder is not scattered and is more compact when the workpiece 8 is printed. After printing, the metal powder 9 and the formed workpiece 8 are moved out of the vacuum printing chamber 1 to a cleaning room through the follow-up powder cylinder. When printing next time, a new follow-up powder cylinder is printed out together with a new workpiece. The vacuum printing chamber 1 of the equipment does not need to leave a rising space (height space) for moving the formed workpiece out of the working chamber, does not need a space (horizontal space) of the powder recovery cylinder, and saves the size of the equipment. The vacuum system 6 does not need to be large because the space of the vacuum printing chamber 1 and the vacuumizing time are saved. So that the equipment cost can be greatly reduced. After printing, the workpiece is directly pulled out, so that the time for lifting the workpiece out of the fixed powder cylinder is saved, and the follow-up powder cylinder is formed along with the workpiece without occupying any time. The size of the powder cylinder is determined according to the size of a workpiece printed by 3D every time and is only a little larger than the workpiece, so that the powder spreading and printing time can be saved, and the working efficiency is improved.

In this embodiment, the following toner cylinder after printing is shaped like a circular cylinder, which can be seen in fig. 5, 6, 11a, 11b, 12a and 12 b. Size: d1 is more than or equal to 350 and less than or equal to the minimum inner diameter of the workpiece (350 is the inner diameter of the circular ring workbench), the maximum outer diameter of the workpiece is more than or equal to D2 and less than or equal to 1500, and H is more than or equal to 0 and less than or equal to 1500. The size of the follow-up powder cylinder is not fixed, is matched with the size of a part to be formed, has the same height as a workpiece, and can be seen in fig. 18a and 18 b.

With reference to fig. 5, 6, 11a, 11b, 12a and 12b, the thickness t1 of the base plate 7 is equal to 30mm, which is reusable, and the thicknesses of the inner circular wall 71 and the outer circular wall 72 are both t2 equal to 0.1 mm. In the figure, reference numeral 51 is a powder laying compaction device, reference numeral 32 is an electron beam scanning area, reference numeral 8 is a printed workpiece, and reference numeral 9 is metal powder; the surface A is a powder spreading and printing surface, and the elevation is fixed; the surface B is the surface of the workbench, and the elevation changes along with the up-and-down lifting of the workbench 21. The inner circular wall 71 and the outer circular wall 72 of the follow-up powder cylinder are provided with shape correcting devices, the shape of the inner circular wall 72 and the shape of the outer circular wall 72 which are just printed are corrected, the inner circular wall is prevented from inclining towards the inside of the powder (due to solid shrinkage after printing), and the inner circular wall and the outer circular wall are kept to be vertically lengthened. The workpiece 8 is not affected.

In this embodiment, two sets of printing devices 31 and two sets of powder spreading and compacting devices 51 are used, so that the wall of the follow-up powder cylinder is formed by double-layer spiral growth, as shown in fig. 19, and an inner circular wall 71 and an outer circular wall 72 are generated together with the workpiece 8. The pitch of the screw is 2 times of the powder spreading thickness Z1 of each layer, which is 0.1 mm.

The invention provides a scheme for improving the working efficiency by continuously carrying out powder paving and printing at the same time, and the technical problem of continuous and efficient forming can be solved and the working efficiency is improved by simultaneously printing the workpiece 8 and the follow-up powder cylinder. After the workpiece is printed, the powder cylinder is moved out of the vacuum printing chamber 1 along with the workpiece on the workbench 21 along the horizontal direction, so that the height of the printing chamber can be reduced, and the volume of the equipment is effectively reduced; can realize the printing of large-size workpieces.

Since the powder spreading and compacting device 51 and the printing device 31 are fixed on the upper end of the box body 11 of the vacuum printing chamber 1, the workbench 21 rotates and descends, so that the powder spreading is continuously spread on the workbench 21 along a spiral sweeping manner with a circular radius. The powder spreading and compacting device 51 is divided into 10 powder falling cavities along the radial direction, and the powder feeding amount is controlled by 10 powder feeding wheels driven by motors of the powder feeding system respectively, so that the powder feeding amount is gradually increased from the center to the outer. If the printed piece is small, the individual motor can be controlled to stop feeding powder, so that the using amount of the powder is greatly saved.

The workpiece and the powder cylinder are completed by the same powder spreading and printing device, so that the problems of complex structure and space waste caused by the completion of different devices in the prior art are solved, and the printing is simple and easy to implement.

In the powder spreading area, powder is dropped onto the powder cylinder on the work table 21 by the powder spreading and compacting device 51 and is strickled off and compacted. When the well-paved and compacted powder is transferred to a printing area, under the scanning of a high-power electron beam 33 (the maximum power reaches 3KW), the electron beam 33 melts the powder in the cross section of the model, so that the powder is solidified and deposited to form the cross section of a part, and simultaneously, the cross section of a follow-up powder cylinder is formed. Thus, the table 21 is rotated and lowered, and the powder is spread along the circular spiral and printed along the circular spiral. The arrangement of a plurality of sets of spreading and printing devices 31 can improve the working efficiency. The height of the powder laying compaction device 51 and the printing device 31 is constant, and the printed workpiece and the follow-up powder cylinder gradually descend along with the workbench 21.

The specific forming method comprises the following steps:

1. early preparation work: inputting, analyzing, processing, optimizing the process and the like of a three-dimensional graph of a workpiece to be formed; then determining the size of the follow-up powder cylinder, namely determining the adaptive inner and outer diameters, and recording a three-dimensional graph of the follow-up powder cylinder and a graph of a workpiece to be formed into a whole; then, carrying out spiral slicing, and determining a scanning path and parameters (including a printing area, a sequence, a speed, a range, a light spot size, energy level and the like); and processing the data related to the scanning path and the parameters into various instruction codes, and enabling the equipment to return to zero.

The spiral slicing comprises the following steps:

step I, slicing parameter planning:

dividing a three-dimensional model formed by combining a workpiece to be formed and a follow-up powder cylinder into m spiral layer groups uniformly along the Z-axis direction; the Z-direction height of each spiral layer group corresponds to one screw pitch;

referring to fig. 21a, 21b, 22 and 23, each spiral layer set includes j spiral layers; the initial positions of each layer of spiral layer are different, and the initial positions correspond to the positions of the powder spreading compaction devices 51 one by one; height H of the entire workpiece_Workpiece＝H*m；

Uniformly dividing the three-dimensional model into n fan-shaped areas on each layer of spiral layer by taking a C axis and a Z axis as parameters, wherein the angle alpha of each fan-shaped area is 360/n, and the Z value difference of adjacent fan-shaped areas is H/jn; wherein H is the pitch; the inner diameter and the outer diameter of each sector are equal to the adaptive inner diameter and the adaptive outer diameter; the area of the sector area needs to satisfy the following conditions: the print scan area 32 of each set of print units covers at least one sector; each sector is represented by a C-axis parameter (taking a value between 0 and 360 degrees) and a Z-axis parameter (taking a value between 0 and H x m).

Arranging a first spiral layer group:

the n sectors of the first spiral layer are respectively named as region 1, region 2 and region 3, region … … n; the n sectors of the second spiral layer are designated as the 1 'region, the 2' region, the 3 'region … … n' region, respectively; by analogy, the n sectors of the j-th spiral layer are respectively named as 1^(j ^-1)′Zone, 2^(j-1)′Zone, 3^(j-1)′Region … … n^(j-1)′A zone;

and (3) in the second spiral layer group:

the n sectors of the first spiral layer are respectively named as n +1 area, n +2 area, n +3 area … … 2n area; the n sectors of the second spiral layer are designated as n '+ 1, n' +2, n '+ 3 … … 2 n' regions, respectively; by analogy, the n fan-shaped regions of the j spiral layer are respectively named as n^(j-1)′+1 zone, n^(j-1)′+2 zone, n^(j-1)′+3 regions … … 2n^(j-1)′A zone;

and by analogy, in the mth spiral layer group:

the n sectors of the first spiral layer are respectively named as (m-1) n +1 area, (m-1) n +2 area, (m-1) n +3 area … … mn area; the n sectors of the second spiral layer are respectively named as (m-1) n ' +1 region, (m-1) n ' +2 region, (m-1) n ' +3 region … … m ' n ' region; by analogy, the n fan-shaped regions of the j-th spiral layer are respectively named as (m-1) n^(j-1)′+1 zone, (m-1) n^(j-1)′+2 zone, (m-1) n^(j-1)′+3 zone … … m n^(j-1)′A zone;

and step II, slicing the workpiece according to the slicing parameters planned in the step I:

respectively obtaining the outlines of the workpieces corresponding to the sector areas according to the sequence of the area 1, the area 2 and the area 3 … n; similarly according to the 1 'region, the 2' region and the 3 'region … … n'; by analogy, according to 1^(j-1)′Zone, 2^(j-1)′Zone, 3^(j-1)' region … … n^(j-1)′Respectively obtaining the outlines of the workpieces corresponding to the fan-shaped areas; completing a spiral layer group slice;

after completing a 360-degree circumference, sequentially entering the next spiral layer group slice, namely according toA region n +1 region, a region n +2, a region n +3 region … … 2 n; n '+ 1 region, n' +2 region, n '+ 3 region … … 2 n' region; by analogy, n^(j-1)′+1 zone, n^(j-1)′+2 zone, n^(j-1)′+3 regions … … 2n^(j-1)′A zone;

and so on until the end layer; obtaining the outlines of the workpieces corresponding to all the fan-shaped areas;

step III: filling the workpiece outlines of the areas obtained in the step II, and performing scanning path planning on the workpiece outlines obtained by processing to obtain scanning paths; outputting G codes from a starting layer to an ending layer; the order of outputting the G-code for each spiral layer is specifically as follows: [1] zone 1 layer; [2] zone 2 layer; [3] zone 3 layers.

Step IV: according to the slicing parameters, parameters including the rotating speed of the workbench 21, the printing sequence, the printing scanning area 32, the light spot distance, the powder discharging range, the energy level and the like are determined, and the required printing precision is ensured;

determining the rotating speed of the workbench 21 to be matched with the slicing precision;

determining a printing order:

printing from the first spiral layer group to the mth spiral layer group in sequence;

within each spiral layer group, the spiral layers are printed simultaneously by each group of printing devices 31;

determination of print scan area 32:

different spiral layers in each spiral layer group are printed simultaneously by different printing devices 31 respectively;

the spiral layers with the same serial number in each spiral layer group are printed by the same printing device 31;

the print scan area 32 of each set of printing devices 31 covers at least one sector;

determining the powder feeding range:

and determining the powder discharging range according to the size of the adaptive inner diameter and the adaptive outer diameter, so as to control which powder discharging motors need to operate.

After the technical scheme is adopted, the larger the n value is, the smaller the Z value difference of adjacent sectors is, the closer the upper surface of each spiral layer is to a continuous and smooth spiral surface, namely n → ∞ time, h → 0, and the upper surfaces of the sectors are seamlessly spliced into the smooth spiral surface.

The helical slice of the invention is to simplify each layer of the helical surface into a continuous n segments with a certain height difference and vertical to the Z axis, which is shown in figure 21a, figure 21b and figure 22. The height of the entire workpiece, hforkpiece, is H × m. The value of n is set according to the requirements of the surface precision of the workpiece, and is also set in consideration of the requirements of the printing speed and the equipment performance. Each zone is represented by a C-axis parameter (taking a value between 0 and 360m degrees) and a Z-axis parameter (taking a value between 0 and H x m).

In the case of double-spiral printing, the difference in height H ═ H/2n (H is the pitch, and H/2 is the thickness of the printing layer) in the Z-axis direction between adjacent sectors is shown in fig. 22.

The present embodiment includes two groups of printing devices 31, each group of printing devices 31 includes two electron guns, and for convenience of description, the two groups of printing devices 31 are defined as a group a printing device and a group B printing device, respectively; the two electron guns in the group a printing apparatus are defined as an a1 electron gun and an a2 electron gun; the two electron guns in the group B printing apparatus are defined as a B1 electron gun and a B2 electron gun.

The A1 electron gun and the A2 electron gun in the group A printing apparatus print in the order of region 1, region 2, region 3 … … n (first week), region n +1, region n +2, region n +3 … … 2n (second week), region … … (m-1) n +1, (m-1) n +2, and region (m-1) n +3 … … mn;

the B1 electron gun and the B2 electron gun in the B group printing apparatus print in the order of zone 1 ', zone 2', zone 3 '… … n' zone '(first week), n' +1 zone, n '+ 2 zone, n' +3 zone … … 2n 'zone (second week) … … (m-1) n' +1 zone, (m-1) n '+ 2 zone, (m-1) n' +3 zone … … m 'n' zone. The group a printing apparatus and the group B printing apparatus print simultaneously.

If 3-spiral printing is adopted, the printing thickness of each spiral layer is H/3, and H is the thread pitch, as shown in FIG. 23. The table 21 rotates in the rotation direction shown in the drawing, and includes 3 spiral layers in one spiral layer group, each spiral layer is divided into n sectors, and the height difference of each adjacent sector in the Z-axis direction is H/3 n. Three powder spreading and compacting devices 51 are respectively fixed above n, n' and n ″, and three printing areas are respectively formed above the drawing A, B, C for A, B, C electron gun groups (printing devices). The number of guns in each set of printing apparatus is determined by the size of the ring, ensuring that the maximum size of the area of the scan range of each gun does not exceed 200mm (here, the side length of a square). The A electron gun group prints in the order of region 1, region 2, region 3 … … n (first week), region n +1, region n +2, region n +3 … … 2n (second week), region 2n +1, region 2n +2, region 2n +3 … … nm; the B electron gun group prints in the order of the zone 1 'zone, the zone 2', the zone 3 '… … n' zone (first week), the n '+ 1 zone, the n' +2 zone, the n '+ 3 zone … … 2 n' zone (second week); the C electron gun group prints in the order of zone 1 ", zone 2", zone 3 "… … n" (first week), zone n "+ 1 … … zone n" m "(second week).

When the helical slicing is carried out, each sector can be further divided into q small sectors which are arranged along the radial direction, wherein q is a natural number. For example, in the case where each set of printing devices 31 includes two electron guns, which can be divided into 4 sectors arranged in the radial direction, as shown in fig. 24, each electron gun is responsible for printing on two adjacent sectors. Or it may be divided into 6 sectors arranged in the radial direction, and in the case where each set of printing means 31 comprises 3 guns, as shown in fig. 25, each gun is responsible for printing of two adjacent sectors. The number of sectors and the number of guns can be selected according to actual needs.

In order to avoid the problem that the beam quality is affected by the mutual interference of the adjacent electron beams 33 working at the same time due to the close distance, the distance between the two adjacent electron gun spots for controlling the simultaneous printing must be larger than 100 mm.

As shown in fig. 24, each sector printing area is divided into 4 small sectors, which are areas a, b, c, and d, respectively. a. The B region belongs to the printing scanning region of the A1 (or B1) electron gun, and the c and d regions belong to the printing scanning region of the A2 (or B2) electron gun. In fig. 24, the size x is 144mm, which is not a fixed value, and may be 100mm or more.

In order to ensure the beam quality, the areas printed by the A1 and A2 at the same time cannot be connected and are more than 100mm away, and the areas printed at the same time according to the principle are as follows:

a and c;

a and d;

b and d.

If each set of printing devices 31 includes 3 electron guns, a1, a2 and A3 respectively, as shown in fig. 25, the areas a and b belong to the a1 electron gun print scan area, the areas c and d belong to the a2 electron gun print scan area, and the areas e and f belong to the A3 electron gun print scan area. In fig. 25, the size x is 100mm, and is not limited to a fixed value, and may be 100mm or more. In this case, the areas that can be printed simultaneously are arranged as follows according to the above principle:

a. c and e;

a. c and f;

b. d and f;

a. d and f.

By analogy, the multiple electron guns arranged in each group of printing devices 31 can perform partition slice printing according to the principle that adjacent light spots printed at the same time are larger than 100 mm.

Therefore, when the spiral slicing is carried out, the principle is considered, and then the printing area and the printing sequence of each electron gun are controlled, so that the quality of each electron beam can be effectively improved, and the printing quality is improved.

2. The table 21 is prepared at the lowest limit position (see fig. 20) outside the casing 11 of the vacuum printing chamber 1, the substrate 7 is placed on the surface of the table 21, the horizontal moving mechanism on the sliding table 222 is started to horizontally move the table 21 into the vacuum printing chamber 1, and after the table reaches the position, the stop is accurately performed by the limit control.

3. The lifting mechanism on the column 221 is actuated to raise the table 21 to the upper limit position (see fig. 2), at which time the upper surface of the substrate 7 reaches the printing surface elevation position (controlled by the limit).

4. And closing the door 12 of the vacuum printing chamber 1, starting the vacuum system 6, and vacuumizing the vacuum printing chamber 1 to reach the required vacuum value.

5. The electric furnace in the table 21 is started to preheat the substrate 7 to a required preheating temperature.

6. After the rotating speed of each motor of the automatic powder feeding assembly 4 is adjusted to a required value, the rotating direction and the rotating speed of a rotary motor and a lifting motor of the workbench 21 are adjusted to the required value; the motors of the automatic powder feeding assembly 4, the rotary motor and the lifting motor are started, and the electric furnaces on the two sides of the worktable 21 are started to maintain the temperature of the powder on the substrate 7. The automatic powder feeding assembly 4 is responsible for quantitatively feeding powder to the powder spreading compaction assembly 5 (located on an x axis), and the powder spreading compaction assembly 5 uniformly compacts the powder on the substrate 7 of the workbench 21; meanwhile, preheating, and enabling the workbench 21 to rotate at a constant speed and descend;

7. when the workbench 21 rotates to reach the printing scanning area 32 for the first time, all the electron guns or lasers 311 (the maximum power reaches 3KW) are turned on, scanning is carried out according to a scanning path, powder in the cross section of the model is melted, and the powder is solidified and deposited to form a workpiece cross section and a follow-up powder cylinder cross section;

note: the two sets of the powder paving and compacting device 51 and the printing device 31 of the embodiment work in the

steps

6 and 7 simultaneously; when j sets of the powder laying compaction device 51 and the printing device 31 are included, the j sets of the powder laying compaction device 51 and the printing device 31 are also operated in 6 and 7 steps at the same time, wherein j is a positive integer greater than or equal to 2.

8. During the process that the worktable 21 rotates for a circle from 0 bit, the worktable 21 gradually reduces the height of 2 layer thickness under the action of the lifting mechanism according to instructions. Because the double-helix powder spreading printing is adopted, 2 layers can be printed on the workbench 21 in one rotation, if j sets of powder spreading compaction devices 51 and the printing device 31 are included, j layers of the spiral powder spreading printing are realized, j layers can be printed on the workbench 21 in one rotation, and the number of the printing layers is consistent with the number of the powder spreading compaction devices 51.

9. And enters the worktable 21 to descend in a second rotation and print a third layer … … and a fourth layer … … simultaneously, and continues to descend in a third rotation and print a fifth layer and a sixth layer simultaneously, and descend in a fourth rotation and print a seventh layer and an eighth layer simultaneously.

Similarly, if j sets of the powder spreading and compacting device 51 and the printing device 31 are included, the working table 21 is rotated and descended for the second round, the (j + 1) th layer and the (j + 2) th layer … … are printed, the rotation and descent for the third round are continued, the (2 j + 1) th layer, the (2 j + 2) th layer … … and the (3 j + 1) th layer are printed simultaneously, and the (3 j + 2) th layer … … and the 4j th layer are printed simultaneously;

10. and (3) closing the electric furnace in the workbench 21, continuously rotating and descending the workbench 21 at a constant speed, continuously rotating and descending the workbench 21 in the fifth cycle, printing the ninth layer and the tenth layer at the same time, rotating and descending the sixth cycle, printing the eleventh layer and the twelfth layer at the same time, and rotating and descending the seventh cycle, printing the thirteenth layer and the fourteenth layer at the same time.

If j sets of the powder spreading compaction device 51 and the printing device 31 are included, the workbench 21 continues to rotate at a constant speed and descends, continues to rotate and descend for the fifth cycle and prints the 4j +1 th layer, the 4j +2 th layer … … the 5j th layer, rotates and descends for the sixth cycle and prints the 5j +1 th layer, the 5j +2 th layer … … the 6j th layer, and rotates and descends for the seventh cycle and prints the 6j +1 th layer, the 6j +2 th layer and the 7j th layer.

11. And (3) closing the automatic powder feeding assembly 4, the rotating motor and the lifting motor, closing the electric furnaces on two sides of the workbench 21 and closing the electron gun until the printing of the workpiece and the wall of the follow-up powder cylinder is finished.

12. The lifting motor of the working table 21 is started to ensure that the working table 21 and the follow-up powder cylinder on the working table are lowered to the lowest point.

13. And when the temperature of the vacuum printing chamber 1 is reduced to the room temperature, opening an air release valve of the vacuum printing chamber 1 to restore the environment of the vacuum printing chamber 1 to the atmospheric pressure.

13. The door opening motor is started to open the door 12.

14. The sliding table 222 is started to horizontally move the motor, so that the working table 21 and the follow-up powder cylinder on the working table are horizontally moved out of the working chamber.

15. Taking down the follow-up powder cylinder and the parts therein together with the metal powder 9 from the workbench 21 by using a special tool and conveying the follow-up powder cylinder and the parts to a cleaning room;

16. in the cleaning room, the cleaning powder is recycled, the cylinder wall is processed into powder for recycling, and the substrate 7 is reused.

Example two

The EBSM device of this embodiment is the same as the first embodiment, and the control system is as shown in fig. 27, and the main control portion is composed of a CNC system, a PLC, an industrial personal computer, a server, and an electron gun control cabinet. The CNC system performs servo control on each motor shaft of the rotary driving mechanism, the lifting mechanism and the horizontal moving mechanism of the workbench 21, performs servo control on each shaft of the dynamic powder repair device, and performs 3-shaft double-gantry linkage interpolation motion control. The PLC controls the powder paving compaction assembly 5, the dynamic shaping device, the vacuum system 6, the powder feeding assembly 4, the electric furnace, the pneumatic part and the switch door of the vacuum printing chamber 1, and data transmission and instruction interaction are carried out through a communication bus and a CNC system. The industrial personal computer performs data sampling and analysis on the 21C-axis circular grating of the workbench through the grating ruler reading board card, acquires the exact position of the C axis, compares the exact position with the prior normal operation program section, and performs real-time correction work; at the same time, an electron gun control program is executed. The industrial personal computer sends the control code to the electronic gun control cabinet through the network port, and the multi-electronic gun cooperative control and the real-time matching with the rotating position of the workbench 21 are carried out. The server carries out path planning on the workpiece to be formed, fuses the process parameters to the control codes, and generates an electron gun signal generation program section, a printing characteristic attribute identification program section, a calibration parameter table and other extensible user-defined extensible program sections. The calibration parameter table is a calibration deviation value of each key point of the electron gun and guides a real printing path of the electron gun;

the control system comprises the following working steps:

1. early preparation work: inputting, analyzing, processing, optimizing the process and the like of a three-dimensional graph of a workpiece in a server; determining the size of the powder cylinder, and recording a three-dimensional graph of the powder cylinder and a workpiece graph together; then carrying out spiral slicing; determining a process route and parameters (including a printing area, a sequence, a speed, a range, a light spot size, energy height and the like); processing the data into various instruction codes and related parameters, and downloading the instruction codes and the related parameters into an industrial personal computer for later use; the equipment is reset to zero, and each error parameter is cleared and reset.

2. The industrial personal computer sends a start instruction, the CNC immediately starts working, the workbench 21 is controlled to prepare at the lowest limit position outside the box body 11, the substrate 7 is placed on the surface of the workbench 21, the sliding table 222 horizontal moving mechanism is started, the workbench assembly 2 is horizontally moved into the vacuum printing chamber 1, and after the substrate reaches a position, the accurate parking is realized through limit control.

3. The CNC starts the lifting mechanism of the workbench 21 to lift the workbench 21 to the upper limit position, and at this time, the upper surface of the substrate 7 reaches the elevation position of the printing surface (controlled by limit).

4. CNC and PLC communication, the chamber door 12 of control equipment is closed, and control pneumatic system locks chamber door 12, starts PLC vacuum system 6 control program afterwards, carries out the evacuation to the real empty room of equipment, reaches the required vacuum value.

5. The PLC starts the electric furnace in the table 21 to preheat the substrate 7 to a required preheating temperature.

6. After the PLC adjusts the rotating speed of each motor of the powder feeding assembly to a required value, the rotation of the workbench 21 and the rotation direction and the rotating speed of the lifting motor are adjusted to the required value. The rotation and elevation motors of the powder feeding assembly and the rotary table 21 are simultaneously started, and the electric furnaces at both sides of the table 21 are started to maintain the temperature of the powder on the substrate 7. The powder feeding assembly is responsible for quantitatively feeding powder to a powder spreading and compacting device 51 (positioned on an x axis), the powder spreading and compacting device 51 uniformly compacts the powder on the substrate 7 of the workbench 21 and simultaneously preheats the powder, and the workbench 21 rotates at a constant speed and descends;

7. when the workbench 21 rotates to reach the printing scanning area 32 for the first time, the industrial personal computer monitors the rotation angle of the C axis to be in place, and then controls the electronic gun control cabinet, so that a high-power electron beam 33 (the maximum power reaches 3KW) is turned on, powder in the cross section of the model is melted under scanning according to a scanning path input by the computer, and the powder is solidified and deposited to form a part cross section and a follow-up powder cylinder cross section;

note: the two sets of lay-down compaction apparatus 51 and electron beam 33 scans were performed simultaneously for

steps

6 and 7.

8. In the process that the workbench 21 rotates for one circle from 0 bit, the workbench 21 gradually reduces the height of 2 layers of thickness under the action of the electric lifting mechanism according to the command sent by the CNC (because double-helix powder spreading printing is adopted, 2 layers of thickness can be printed after one circle of rotation of the workbench 21);

9. the entry table 21 is lowered for a second rotation while printing the third and fourth layers … … continuing the third rotation while printing the fifth and sixth layers and the fourth rotation while printing the seventh and eighth layers.

10. The PLC controls to close the electric furnace in the workbench 21, the workbench 21 continues to rotate at a constant speed and descend, the workbench continues to rotate and descend in the fifth circle while printing the ninth layer and the tenth layer, the workbench continues to rotate and descend in the sixth circle while printing the eleventh layer and the twelfth layer, and the workbench continues to rotate and descend in the seventh circle while printing the thirteenth layer and the fourteenth layer.

11. Until the printing of the workpiece and the wall of the follow-up powder cylinder is finished, the PLC controls to close the powder feeding assembly and the rotating and lifting motors of the rotary worktable 21, the electric furnaces on the two sides of the worktable 21 are closed, and the industrial personal computer controls to close the electronic gun.

12. The PLC starts the lifting motor of the working platform 21 to enable the working platform 21 and the follow-up powder cylinder on the working platform to be lowered to the lowest point.

13. When the temperature of the vacuum chamber is reduced to room temperature, the PLC controls to open the air release valve of the vacuum chamber, so that the environment of the vacuum chamber recovers to atmospheric pressure.

13. The PLC starts the door opening motor to open the door 12.

14. The CNC starts the sliding table 222 to move the motor horizontally, so that the working table 21 and the follow-up powder cylinder on the working table move out of the working chamber horizontally.

The invention breaks through the size limit of electron beam 33 metal additive manufacturing large-size complex parts, the maximum printing size can reach D1500 multiplied by D350 multiplied by 1500, and the invention is originated at home and abroad. Is suitable for 3d printing of large complex ring parts (8 in figure 12 a) and simultaneously printing a plurality of complex parts (8 in figure 12 b) of the same or different types.

Claims

1. The utility model provides an EBSM equipment based on follow-up powder jar which characterized in that: comprises a vacuum printing chamber (1), a workbench component (2), a printing component (3), a powder feeding component (4), a powder paving and compacting component (5), a vacuum system (6) and a control system;

the vacuum printing chamber (1) comprises a box body (11) and a box door (12) positioned on the side wall of the box body (11);

the workbench component (2) comprises a workbench (21) with an annular workbench surface and a workbench supporting and driving device (22); an electric furnace is arranged in the workbench (21); the workbench supporting and driving device (22) can drive the workbench (21) to rotate in a plane where the workbench surface is located, namely an XY plane, and can move in the Z direction and move in and out of the vacuum printing chamber (1) through the box door (12) in the X direction;

the printing component (3) is fixed at the top of the vacuum printing chamber (1); the printing assembly (3) comprises j groups of printing devices (31), each group of printing devices (31) comprising at least two electron guns or lasers (311); the electron guns or lasers (311) in each set of printing devices (31) are arranged along the same straight line; each group of printing devices (31) form printing scanning areas (32) in the same radius area of the annular table top of the workbench, and the printing scanning areas (32) of each group of printing devices (31) are uniformly distributed in the same circumference; j is a positive integer greater than or equal to 2;

the powder feeding assembly (4) is positioned outside the vacuum printing chamber (1) and is used for feeding powder into the powder spreading compaction assembly (5);

the powder spreading and compacting assembly (5) is fixed at the top of the vacuum printing chamber (1), and a powder spreading head is arranged right above the workbench (21) and used for continuously spreading powder in a spiral manner and strickingly compacting the powder on the workbench (21); the powder paving compacting assembly (5) comprises j powder paving compacting devices (51), the projections of the powder paving compacting devices (51) on the annular table top of the workbench are positioned in different radius areas of the annular table top of the workbench, and the projections of the j powder paving compacting devices are uniformly distributed in the same circumference;

an included angle is formed between the projection of each powder laying compaction device (51) on the annular table surface of the workbench and the printing scanning area (32) of each group of printing devices (31);

the vacuum system (6) is used for vacuumizing the vacuum printing chamber (1);

the control system is used for controlling the workbench assembly (2), the printing assembly (3), the powder feeding assembly (4), the powder paving and compacting assembly (5) and the vacuum system (6) to work according to a set time sequence.

2. The follow-up powder cylinder-based EBSM apparatus of claim 1 wherein: j is equal to 2;

the printing scanning areas (32) of the two groups of printing devices (31) are respectively positioned in two radius areas with the same diameter on the annular table surface of the workbench;

the projections of the two powder paving and compacting devices (51) on the annular table top of the workbench are respectively positioned in two radius areas with the same diameter of the annular table top of the workbench;

the projection of the two powder spreading compaction devices (51) on the annular table top of the workbench is vertical to the printing scanning area (32) of the printing device (31) on the annular table top of the workbench.

3. The follow-up powder cylinder-based EBSM apparatus of claim 2 wherein:

the annular table surface of the workbench comprises an inner annular area and an outer annular area;

each group of printing devices (31) comprises two electron guns or lasers (311), and the printing scanning areas (32) of the two electron guns or lasers (311) in each group of printing devices (31) are respectively positioned in the inner circular ring area and the outer circular ring area.

4. The follow-up powder cylinder based EBSM apparatus of any one of claims 1-3 wherein:

the powder feeding assembly (4) comprises at least j powder feeding devices, each powder feeding device is used for feeding powder into one powder spreading compaction device (51);

the powder feeding device comprises a powder feeding shell (41), a plurality of groups of powder wheel assemblies (42) and a plurality of groups of driving assemblies (43), wherein the length direction of the powder feeding shell (41) is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction;

a powder conveying cavity (411) is arranged in the powder conveying shell (41), at least one powder inlet (412) is formed in the top of the powder conveying shell, the powder inlet (412) is communicated with the powder conveying cavity (411), a plurality of powder outlet channels (413) communicated with the powder conveying cavity (411) are formed in the bottom of the powder conveying shell along the X direction, and the number of the powder outlet channels (413) is the same as that of the powder wheel assemblies (42) and the driving assemblies (43);

the powder wheel assembly (42) comprises a transmission shaft (421), a powder feeding wheel (422) and two side leakage prevention wheels (423), wherein the transmission shaft (421) is arranged in the powder outlet channel (413), and the axis of the transmission shaft is parallel to the Y direction; the powder feeding wheel (422) and the side leakage prevention wheel (423) are sleeved on the transmission shaft (421), the powder feeding wheel (422) is positioned between the two side leakage prevention wheels (423), a plurality of wheel grooves of the powder feeding wheel (422) are uniformly distributed along the circumferential direction of the powder feeding wheel (422), a plurality of annular wheel grooves of the side leakage prevention wheel (423) are arranged along the axial direction of the side leakage prevention wheel (423) and are arranged at an angle of 90 degrees with the wheel grooves of the powder feeding wheel (422);

the driving assembly (43) is arranged outside the powder feeding shell (41), and the output end of the driving assembly is connected with the transmission shaft (421) and is used for driving the transmission shaft (421) to rotate;

the powder outlet channel (413) comprises a first channel (4131), a second channel (4132) and a third channel (4133) which are sequentially communicated along the Z direction; the first channel (4131) is a trapezoidal channel, the large end of the first channel is communicated with the powder feeding cavity (411), the small end of the first channel is communicated with the second channel (4132), the second channel (4132) is obliquely arranged with the XY plane, the central line of the second channel (4132) and the central line of the first channel (4131) are arranged at a certain angle when seen from the XZ plane, and the central line of the third channel (4133) is parallel to the central line of the first channel (131);

the powder wheel assembly (42) is arranged in the second channel (4132), and the gap between the powder feeding wheel (422) and the second channel (4132) is equal to the maximum size of the powder particles, so that the powder particles can smoothly pass through.

5. The follow-up powder cylinder-based EBSM apparatus of claim 4, wherein:

the central line of the second channel (4132) and the central line of the first channel (4131) are arranged at an angle of 100-160 degrees; the width of the small end of the first channel (4131) is the same as that of the powder feeding wheel (422), and the width of the third channel (4133) is the same as the sum of the widths of the wheel grooves of the powder feeding wheel (422) and the two side leakage prevention wheels (423).

6. The follow-up powder cylinder-based EBSM apparatus of claim 4, wherein:

the powder spreading compaction device (51) comprises a powder dropping box (511) and powder scraping assemblies (512), wherein the powder scraping assemblies (512) are in multiple groups and are all arranged at the bottom of the powder dropping box (511); setting the length direction of the powder dropping box (511) as the X direction, the width direction as the Y direction and the height direction as the Z direction;

a plurality of powder falling cavities (5111) which are distributed along the X direction are arranged in the powder falling box (511), and a plurality of scattering plates (5112) are arranged in the powder falling cavities (5111) and are used for scattering powder falling into the powder falling cavities (5111); the top of the powder dropping box (511) is provided with a plurality of powder inlets (5113) communicated with the powder dropping cavity (5111), and the bottom is provided with a plurality of powder outlets (5114) communicated with the powder dropping cavity (5111);

the powder scraping component (512) comprises a soft scraper (5121), a hard scraper (5122) and a compacting plate (5123), and the powder outlet (5114), the soft scraper (5121), the hard scraper (5122) and the compacting plate (5123) are sequentially arranged along the Y direction;

the soft scraper (5121) is of a comb-tooth-shaped structure and comprises a plurality of scraping strips (51211) arranged along the X direction;

the powder scraping end face of the hard scraper blade (5122) and the powder scraping end face (51212) of the soft scraper blade (5121) are equal in height in the Z direction;

the powder pressing end face (51231) of the compacting plate (5123) is lower than the powder scraping end face of the hard scraper blade (5122) in the Z direction;

the scattering plates (5112) are arranged on a front side plate and a rear side plate of the powder falling box (511) opposite along the Y direction, and the scattering plates (5112) arranged on the front side plate and the scattering plates (5112) arranged on the rear side plate are arranged in a staggered manner in the X direction and the Z direction;

each powder inlet (5113) in the powder paving and compacting device 51 is respectively communicated with one powder outlet channel (413) in the powder feeding device.

7. The follow-up powder cylinder-based EBSM apparatus of claim 6 wherein:

the scattering plate (5112) is a triangular flat plate, and the inclined side edge of the triangular flat plate is used for scattering powder falling into the powder falling cavity (5111);

the powder pressing end face (51231) of the pressing plate (5123) is an arc-shaped face;

a plurality of partition plates (5124) are also provided between the hard scraper (5122) and the compacting plate (5123).

8. The follow-up powder cylinder-based EBSM apparatus of claim 6 wherein:

the workbench supporting and driving device (22) comprises a rotary driving mechanism, a lifting mechanism and a horizontal moving mechanism;

the rotary driving mechanism can drive the workbench (21) to rotate in an XY plane;

the lifting mechanism can drive the workbench (21) to move along the Z direction;

the horizontal moving mechanism can drive the workbench (21) to move along the X direction, so that the workbench (21) can move in and out of the vacuum printing chamber (1).

9. The slave powder cylinder-based EBSM apparatus of claim 8 wherein: also comprises an auxiliary heating and cooling system;

the auxiliary heating and cooling system comprises a preheating unit (15), a demagnetization unit (16) and a water cooling unit;

the demagnetization units (16) are at least one group, and each group of demagnetization units (16) comprises two demagnetization conducting wires (161) which are oppositely arranged in the vacuum printing chamber (1) and are used for weakening the magnetic field intensity of a printing area;

the preheating unit (15) comprises a top heat-insulation plate (151), a heat-insulation box body (152) and a heating device;

the heat insulation box body (152) is arranged in the vacuum printing chamber (1), a heat insulation layer (154) is arranged in the heat insulation box body, and at least two atmosphere channels (156) are arranged at the top of the heat insulation box body and used for inflow and outflow of external atmosphere gas;

the top heat-insulation plate (151) is arranged above the heat-insulation box body (152) to form a heat-insulation cavity with the heat-insulation box body (152), and meanwhile, an electron beam or laser beam channel (157) and a powder falling channel (158) which can enable an electron beam or a laser beam to pass through are arranged on the top heat-insulation plate (151);

during printing, the workbench (21) is positioned in the heat preservation cavity;

the water cooling unit is arranged on the side wall of the heat preservation box body (152) along the X direction and used for cooling the heat preservation box body (152).

10. The slave powder cylinder-based EBSM apparatus of claim 9 wherein: the device also comprises a dynamic shape corrector, which is used for correcting the inner and outer circular walls (72) of the follow-up powder cylinder formed in the printing process.

11. The slave powder cylinder-based EBSM apparatus of claim 10 wherein: the control system comprises a CNC system, a PLC, a server, an industrial personal computer and a printing device control cabinet;

the PLC controls the powder feeding component (4), the powder paving and compacting component (5), the dynamic shaping device, the vacuum system (6), the electric furnace and a box door (12) of the vacuum printing chamber (1); data transmission and instruction interaction are carried out through a communication bus and a CNC system;

the server carries out three-dimensional graph input, analysis, processing and process optimization on the workpiece to be formed and the follow-up powder cylinder; performing spiral slicing, determining a scanning path and parameters, processing the scanning path and the parameters into various instruction codes and related parameters, and generating a control program of the printing component (3);

the industrial personal computer monitors the C-axis rotation angle of the workbench (21), samples and analyzes the C-axis rotation angle, acquires the exact C-axis position, compares the exact C-axis position with the C-axis theoretical position corresponding to the currently-operated electron gun signal generation control program segment, calculates the error between the exact C-axis position and the C-axis theoretical position, and corrects the current electron gun signal generation control program segment; at the same time, executing a control program of the printing assembly (3);

and the printing device control cabinet receives a control program sent by the industrial personal computer, and performs cooperative control on j groups of printing devices (31) and real-time matching with the rotating position of the workbench (21).