阅读说明：本技术 一种用于高温打印系统的刮粉装置 (Powder scraping device for high-temperature printing system ) 是由 王志翔 卢秉恒 王红宇 赵纪元 于 2020-12-11 设计创作，主要内容包括：本发明提供一种用于高温打印系统的刮粉装置,解决现有刮粉装置在高温环境中存在不能均匀刮粉、存在热变形以及刮粉精度较低的问题。该刮粉装置,包括支撑架和刮刀组件；支撑架的内部设置有冷却腔,用于对刮刀组件进行冷却；刮刀组件设置在支撑架的底端,包括刮刀座、压实刀和n个刮刀；刮刀座设置在支撑架的底端,设定刮刀座的长度方向为X方向,宽度方向为Y方向,高度方向为Z方向；刮刀和压实刀沿Y方向依次设置在刮刀座的底端；刮刀为梳齿形结构,包括沿X方向设置的多个刮条；压实刀为U形板结构,U形板上设置有沿X方向排布的多个U形狭缝,使得压实刀形成U形梳齿结构；压实刀的压粉弧面在Z方向低于刮刀的刮粉端面。(The invention provides a powder scraping device for a high-temperature printing system, which solves the problems that the existing powder scraping device can not uniformly scrape powder in a high-temperature environment, has thermal deformation and is low in powder scraping precision. The powder scraping device comprises a support frame and a scraper component; a cooling cavity is arranged in the support frame and used for cooling the scraper component; the scraper component is arranged at the bottom end of the support frame and comprises a scraper seat, a compaction cutter and n scrapers; the scraper seat is arranged at the bottom end of the support frame, the length direction of the scraper seat is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction; the scraper and the compaction knife are sequentially arranged at the bottom end of the scraper seat along the Y direction; the scraper is of a comb-tooth-shaped structure and comprises a plurality of scraping strips arranged along the X direction; the compaction knife is in a U-shaped plate structure, and a plurality of U-shaped slits distributed along the X direction are arranged on the U-shaped plate, so that the compaction knife forms a U-shaped comb tooth structure; the powder pressing cambered surface of the compacting knife is lower than the powder scraping end surface of the scraper in the Z direction.)

1. A powder scraping device for a high-temperature printing system is characterized in that: comprises a support frame (1) and a scraper component (2);

a cooling cavity (11) is arranged in the support frame (1) and used for cooling the scraper component (2);

the scraper component (2) is arranged at the bottom end of the support frame (1) and comprises a scraper seat (21), a compaction cutter (22) and n scrapers (23), wherein n is an integer greater than or equal to 2;

the scraper seat (21) is arranged at the bottom end of the support frame (1), the length direction of the scraper seat (21) is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction;

the n scrapers (23) and the compaction cutter (22) are sequentially arranged at the bottom end of the scraper seat (21) along the Y direction;

the scraper (23) is of a comb-tooth-shaped structure and comprises a plurality of scraping strips (231) arranged along the X direction;

the compaction cutter (22) is of a U-shaped plate structure, and a plurality of U-shaped slits (223) distributed along the X direction are formed in the U-shaped plate, so that the compaction cutter (22) forms a U-shaped comb tooth structure;

the powder pressing cambered surface (224) of the compacting knife (22) is lower than the powder scraping end surface (232) of the scraper (23) in the Z direction.

2. The doctor apparatus of claim 1, wherein: the U-shaped plate comprises two vertical plates (221) and an arc-shaped plate (222) arranged between the two vertical plates (221); the scraper component (2) further comprises a first clamping plate (24) and a second clamping plate (25), wherein the first clamping plate (24) is arranged at the bottom end of the scraper seat (21) and positioned at two sides of the scraper (23) and used for supporting the scraper (23); the second clamping plate (25) is arranged at the bottom end of the scraper seat (21), is positioned on two sides of the vertical plate (221), and is used for supporting the vertical plate (221).

3. The doctor apparatus for a high temperature printing system as claimed in claim 2, wherein: be provided with on first splint (24), second splint (25) and arrange along the X direction along a plurality of bar holes (241) that the Z direction extends, simultaneously, the bottom of first splint (24), second splint (25) is provided with and arranges along the X direction and extend along the Z direction, and a plurality of recesses (242) with bar hole (241) intercommunication for first splint (24), second splint (25) form the flexible deformation region.

4. The doctor apparatus for a high temperature printing system as claimed in claim 3, wherein: the scraper component (2) further comprises a partition plate (26) and a pressing plate (27), and the top ends of the scraper (23), the compaction cutter (22), the first clamping plate (24) and the second clamping plate (25) are pressed at the bottom end of the scraper seat (21) through the partition plate (26) and the pressing plate (27) and are fixedly connected through a connecting piece.

5. The doctor apparatus for a high temperature printing system as claimed in claim 4, wherein: all be provided with locating hole (233) on scraper (23), riser (221), first splint (24), second splint (25), baffle (26) and clamp plate (27) for realize with the quick accurate installation of scraper seat (21).

6. A doctor apparatus for a high temperature printing system as claimed in any one of claims 1 to 5, wherein: the scraper (23), the compaction knife (22), the first clamping plate (24) and the second clamping plate (25) are all made of high-temperature-resistant materials.

7. The doctor apparatus for a high temperature printing system as claimed in claim 6, wherein: the distance t between two adjacent scrapers (23) is 2.5mm, and the radius of the arc surface of the powder pressing arc surface (224) is 10 mm.

8. The doctor apparatus for a high temperature printing system as claimed in claim 7, wherein: the thickness of the scraper (23) and the thickness of the compaction knife (22) are 0.1mm, the width a of the comb teeth is 0.85mm, and the distance b between the comb teeth is 0.15 mm.

Technical Field

The invention belongs to the field of additive manufacturing, and particularly relates to a powder scraping device for a high-temperature printing system.

Background

Electron Beam Selective Melting (EBSM) metal 3D printing uses an electron beam as an energy source to manufacture a solid part 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 EBSM technology has the characteristics of high density of a finished piece, low oxygen content, low thermal stress, difficult deformation and cracking, low price of powder consumables, recyclable unshaped powder, high printing efficiency and the like, has unique advantages and application values in the aspect of 3D printing of metal materials, particularly refractory metal materials difficult to process, and is widely applied in the fields of orthopedics medical treatment, aerospace and the like.

The process of Electron Beam Selective Melting (EBSM) metal additive manufacturing comprises the following steps: firstly, spreading a layer of powder on the surface of a powder bed, and preheating and insulating the powder by an electron beam to meet the requirements of printing process parameters; secondly, selectively melting the electron beams under the control of a computer according to the cross section profile information, melting the metal powder under the bombardment of the electron beams, and bonding the metal powder with the formed part below to realize layer-by-layer accumulation until the whole part is completely melted; and finally, removing redundant powder to obtain the required three-dimensional product.

In the 3D metal printing process, the density of the powder and whether the powder is spread flatly directly determine the density, strength, precision and quality of a formed part, so that the problem of improving the density of the powder is an urgent need to be solved. However, the existing powder scraping device has the following defects: (1) the powder is scraped by a hard scraper, so that the efficiency is low; (2) when the powder spreading roller spreads the powder material into the forming cylinder, a large amount of powder is accumulated at the front end of the powder spreading roller, and when the accumulation amount is large, the powder overflows to the rear of the powder spreading roller, so that the damage of the spread powder is caused, the powder spreading resistance is increased, and the powder scraping precision is low; (3) when only the hard scraper is used for scraping powder, because the paved powder is not compacted, the powder density is reduced, so that the density of a formed part is reduced, and the porosity of the formed part is improved; (4) the powder scraping pressure is real-time in a parallel reciprocating mode, so that the problems of discontinuous powder scraping and incapability of realizing uniform powder scraping exist, and the powder scraping precision is low; (5) the existing spiral powder scraping compaction mode is only provided with one set of powder scraping device, has low powder scraping efficiency and is only used in laser printing; (6) the existing spiral powder scraping compaction mechanism needs to move up and down, so that the powder scraping device has a complex structure and occupies a large space; 7) when printing during EBSM equipment, EBSM equipment need keep lasting high temperature environment, and current scrape whitewashed compaction device has the heat altered shape problem in high temperature environment, leads to scraping whitewashed precision lower.

Disclosure of Invention

The invention aims to solve the problems that the existing powder scraping device cannot uniformly scrape powder in a high-temperature environment, has thermal deformation and is low in powder scraping precision, and therefore the powder scraping device for the high-temperature printing system is provided.

In order to realize the purpose, the technical scheme adopted by the invention is as follows:

a powder scraping device for a high-temperature printing system comprises a supporting frame and a scraper assembly; a cooling cavity is arranged in the support frame and used for cooling the scraper component; the scraper component is arranged at the bottom end of the support frame and comprises a scraper seat, a compaction cutter and n scrapers, wherein n is an integer greater than or equal to 2; the scraper seat is arranged at the bottom end of the support frame, the length direction of the scraper seat is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction; the n scrapers and the compaction cutter are sequentially arranged at the bottom end of the scraper seat along the Y direction; the scraper is of a comb-tooth-shaped structure and comprises a plurality of scraping strips arranged along the X direction; the compaction knife is of a U-shaped plate structure, and a plurality of U-shaped slits distributed along the X direction are formed in the U-shaped plate, so that the compaction knife forms a U-shaped comb tooth structure; and the powder pressing cambered surface of the compacting knife is lower than the powder scraping end surface of the scraper in the Z direction.

Furthermore, the U-shaped plate comprises two vertical plates and an arc-shaped plate arranged between the two vertical plates; the scraper component also comprises a first clamping plate and a second clamping plate, wherein the first clamping plate is arranged at the bottom end of the scraper seat, is positioned at two sides of the scraper and is used for supporting the scraper; the second clamping plate is arranged at the bottom end of the scraper seat and located on two sides of the vertical plate, and is used for supporting the vertical plate.

Further, be provided with on first splint, the second splint and arrange along the X direction a plurality of bar holes that extend along the Z direction, simultaneously, the bottom of first splint, second splint is provided with and arranges along the X direction and extend along the Z direction, and with a plurality of recesses of bar hole intercommunication for first splint, second splint form the flexible deformation region.

Furthermore, the scraper component also comprises a partition plate and a pressing plate, and the top ends of the scraper, the compaction knife, the first clamping plate and the second clamping plate are pressed at the bottom end of the scraper seat through the partition plate and the pressing plate and are fixedly connected through a connecting piece.

Furthermore, all be provided with the locating hole on scraper, riser, first splint, second splint, baffle and the clamp plate for realize with the quick accurate installation of scraper seat.

Further, the scraper, the compaction knife, the first clamping plate and the second clamping plate are all made of high-temperature-resistant materials.

Further, the distance t between two adjacent scrapers is 2.5mm, and the radius of the arc surface of the powder pressing arc surface is 10 mm.

Further, the thickness of the scraper and the compacting knife is 0.1mm, the width a of the comb teeth is 0.85mm, and the distance b between the comb teeth is 0.15 mm.

Compared with the prior art, the technical scheme of the invention has the beneficial effects that:

1. the compacting knife of the powder scraping and compacting device is bent into a semicircular arc shape by the thin plate with the gap, and the powder on the powder bed is compacted by using the arc surface as a compacting surface, so that the thermal stress can be effectively released, and the compacting precision is prevented from being influenced by the thermal deformation of the compacting plate.

2. The scraper of the powder scraping and compacting device adopts a double-layer comb-shaped structure, the comb-shaped structure can effectively release thermal stress, and the thermal deformation of the scraper can not be caused, so that the powder scraping precision is improved; simultaneously, double-deck sword can play the replenishment and strickle the effect, makes the powder more effectively evenly spread on the powder bed of swivel work head, and in addition, the distance between the double-deck scraper can be adjusted according to actual conditions, pushes away unnecessary powder to swivel powder bedside, pushes out the powder bed at last for scrape powder efficiency and promote by a wide margin.

3. The powder scraping and compacting device can be matched with continuous uninterrupted printing, high-efficiency production is realized, and quick printing of large-size complex parts is possible. Meanwhile, when the device is used in large-size Electron Beam Selective Melting (EBSM) equipment, the structure is compact, the occupied space is small, and the space of a vacuum printing chamber is saved, so that the equipment cost and the vacuumizing time are saved.

Drawings

FIG. 1 is a schematic structural diagram of a powder scraping device for a high-temperature printing system according to the present invention;

FIG. 2 is a schematic structural view of a doctor assembly of the present invention;

FIG. 3 is an enlarged view of a portion of the doctor assembly of the present invention;

FIG. 4 is an enlarged partial schematic view of FIG. 3;

FIG. 5 is a schematic view of the construction of the doctor blade of the present invention;

FIG. 6 is an enlarged, fragmentary, schematic view of the doctor blade of the present invention;

FIG. 7 is a schematic view of the construction of the compaction tool of the present invention;

fig. 8 is an enlarged partial schematic view of the compaction tool of the present invention.

Reference numerals: 1-support frame, 2-scraper component, 11-cooling cavity, 12-side plate, 21-scraper seat, 22-compaction cutter, 23-scraper, 24-first clamping plate, 25-second clamping plate, 26-partition plate, 27-pressing plate, 221-vertical plate, 222-arc plate, 223-U-shaped slit, 224-powder pressing arc surface, 231-scraping strip, 232-powder scraping end surface, 233-positioning hole, 234-strip mounting hole, 241-strip hole and 242-groove.

Detailed Description

The invention is described in further detail below with reference to the figures and specific embodiments.

The invention provides a powder scraping device for a high-temperature printing system, which is used in large-size Electron Beam Selective Melting (EBSM) equipment and is used for efficiently, uniformly and accurately paving metal powder on a powder bed and compacting the metal powder so as to lay a foundation for printing. The powder scraping and compacting device can be matched with continuous uninterrupted printing, high-efficiency production is realized, and quick printing of large-size complex parts is possible. Meanwhile, when the device is used in large-size Electron Beam Selective Melting (EBSM) equipment, the structure is compact, the occupied space is small, and the space of a vacuum printing chamber is saved, so that the equipment cost and the vacuumizing time are saved.

As shown in fig. 1, the powder scraping device for a high-temperature printing system of the present invention comprises a supporting frame 1 and a scraper blade assembly 2. When the EBSM technology is used for producing large-size parts, the large-size parts are generally in a continuous working state in order to improve the efficiency, at the moment, all parts are in a continuous high-temperature environment, and the temperature can reach 1000 degrees. The support frame 1 is provided with the cooling cavity 11, the side plates 12 on two sides of the cooling cavity 11 have certain thickness, the effect of supporting the scraper component 2 is achieved, the rigidity of the scraper component 2 is guaranteed, and therefore accurate powder scraping and compacting are achieved. In the embodiment of the invention, the support frame 1 is made of stainless steel and is in a hollow box structure, cooling water is introduced into an inner cavity of the support frame to cool the scraper component 2, and the temperature of the upper surface of a cutter holder of the scraper component 2 is ensured to be 60 ℃ and the temperature of the lower surface of the cutter holder of the scraper component 2 is ensured to be 80 ℃.

As shown in fig. 2 and 3, the scraper assembly 2 of the present invention is disposed at the bottom end of the support frame 1, and includes a scraper seat 21, a compacting knife 22, a partition 26, a pressing plate 27, and n scrapers 23, where n is an integer greater than or equal to 2; the scraper seat 21 is provided at the bottom end of the support frame 1, and supports and mounts the pressing blade 22 and the scraper blade 23, and at this time, the length direction of the scraper seat 21 is set to be the X direction, the width direction is the Y direction, and the height direction is the Z direction, and the mounting of the scraper blade 23 and the pressing blade 22 will be described in detail according to this setting.

As shown in fig. 4, 5 and 6, n doctor blades 23 and compacting blades 22 of the present invention are sequentially disposed at the bottom end of the doctor blade holder 21 in the Y direction. The scraper 23 is of a comb-tooth-shaped structure and comprises a plurality of scraping strips 231 arranged along the X direction; in the embodiment of the invention, the number of the scrapers 23 is preferably two, the scrapers 23 have a function of pushing powder uniformly, when the resistance is large, individual comb teeth can bend to release pressure and then rebound to the original shape without damaging the scrapers, the double scrapers 23 are adopted to better push the powder uniformly, the front scraper 23 plays a role of pre-scraping, and after pre-scraping, the stress of the rear scraper 23 is relatively reduced, so that the powder scraping precision is high.

As shown in fig. 7 and 8, the compacting blade 22 of the present invention has a U-shaped plate structure, and a plurality of U-shaped slits 223 are disposed on the U-shaped plate and arranged along the X-direction, so that the compacting blade 22 forms a U-shaped comb structure. The U-shaped plate may include two vertical plates 221 and an arc-shaped plate 222 disposed between the two vertical plates 221, and may be formed by bending a plate having a thickness h and having a plurality of slits formed in a longitudinal direction. The powder-pressing arc surface 224 of the compacting knife 22 is lower than the powder-scraping end surface 232 of the scraper 23 in the Z direction, that is, there is a height difference between the lowest points of the scraper 23 and the compacting knife 22, and the difference is the compacting amount of the powder. The compacting knife 22 has a radius of the compacting arc surface R, which is determined according to the size of the metal particles and the amount of compaction.

As shown in fig. 4, in order to achieve a stable installation of the compacting blade 22 and the scraper blade 23 without affecting the performance thereof, the scraper assembly 2 of the present invention is provided with a first clamping plate 24 and a second clamping plate 25, wherein the first clamping plate 24 is fixedly arranged at the bottom end of the scraper seat 21 and is located at both sides of the scraper blade 23 for supporting the upper portion of the scraper blade 23; the second clamping plate 25 is fixedly disposed at the bottom end of the scraper seat 21, and is located at two sides of the vertical plate 221, and is used for supporting the upper portion of the vertical plate 221. Be provided with on first splint 24, the second splint 25 along the X direction arrange along a plurality of bar holes 241 that the Z direction extends, simultaneously, the bottom of first splint 24, the second splint 25 is provided with along the X direction arrange along the Z direction extension, and with a plurality of recesses 242 of bar hole 241 intercommunication for first splint 24, the second splint 25 form the flexible deformation region. The flexible deformation area is bent along with the comb-shaped structures of the compaction cutter 22 and the scraper 23, so that the compaction cutter 22 and the scraper 23 are supported, the thermal stress can be effectively released, and the compaction precision is prevented from being influenced by the thermal deformation of the compaction plate.

The scraper 23 of the powder scraping and compacting device adopts a double-layer comb-shaped structure, the comb-shaped structure can effectively release thermal stress, and the thermal deformation of the scraper 23 can not be generated, so that the powder scraping precision is improved; the double-layer knife can play the supplementary effect of strickleing off, and the distance between the double-layer scraper 23 can be adjusted according to actual conditions, enables the powder more effectively evenly to spread on the powder bed of swivel work head, pushes away rotatory powder bed limit to reach few unnecessary powder, pushes out the powder bed at last for scrape powder efficiency and promote by a wide margin.

The compacting knife 22 of the powder scraping and compacting device is bent into a semicircular arc shape by a thin plate with a gap, clamped by a partition plate 26 and then fixed on a knife holder, and the powder on a powder bed is compacted by using the arc surface as a compacting surface. Meanwhile, the scraper blade 23, the compacting blade 22 and the clamping plate are all made of high-temperature resistant materials, such as GH 5188.

When the scraper component 2 of the invention is installed, the top ends of the scraper 23, the compacting knife 22, the first clamping plate 24 and the second clamping plate 25 are pressed on the bottom end of the scraper seat 21 through the clapboard 26 and the pressing plate 27 and are fixedly connected through the connecting piece. Meanwhile, the scraper 23, the vertical plate 221, the first clamping plate 24, the second clamping plate 25, the partition plate 26 and the pressing plate 27 are provided with fixing round holes and strip-shaped mounting holes at two ends, so that the scraper can be quickly and accurately mounted on the scraper seat 21. The powder scraping device is fixed after being installed and arranged on the radius of a circular workbench, the workbench rotates and moves relative to the circular workbench, a scraper 23 and a compacting knife 22 are parallel to each other and have a certain distance, and the powder scraping device and the compacting knife are sequentially arranged behind a powder falling port to realize continuous powder scraping and compacting.

In the powder scraping and compacting device of the present invention, the distance t between two adjacent scraping blades 23 is determined according to practical situations, and the larger the distance is, the better the distance is in principle, but the space structure is not limited to be too large. The thickness of the scraper 23 and the compacting knife 22 of the device is set to be small, the heat transfer is small, certain deformability exists when the scraper and the compacting knife meet special hard points, powder spreading and continuous printing are facilitated, and the knife body is not damaged. In the embodiment of the invention, t is 2.5mm, the thicknesses of the scraper 23 and the compacting knife 22 are 0.1mm, the widths a of the comb teeth of the scraper 23 and the compacting knife 22 are 0.85mm, the distance b between the comb teeth is 0.15mm, and the radius R of the compacting circular arc surface of the compacting knife 22 is 9.9 mm. In actual operation, the height difference of the scraper 23 and the compacting knife 22 can be adjusted according to different kinds of powder, and the values of t, a and b are designed according to actual requirements. The radius of the compacted arc surface is calculated according to the parameters of the powder granularity, the loose density and the compacted density of the powder material, the powder spreading thickness, the rolling reduction, the dynamic friction coefficient of the powder particles and the like, and when the powder granularity is 45-105 mu m, the calculated radius of the arc surface is 10 mm.

The invention discloses a powder scraping device for a high-temperature printing system, which mainly solves the problem that the powder scraping compaction device is easy to deform when working in a continuous high-temperature environment to influence the powder scraping compaction precision, the maximum overall dimension of the device is 65mm multiplied by 615mm multiplied by 555mm, a scraper 23 is 615mm long, a compaction cutter 22 is 615mm long, and the length meets the powder spreading radius range of a circular workbench. (the inner diameter of the circular ring workbench is 350mm, the outer diameter is 1500mm, and the powder spreading radius range (1500 + 350)/2 is 575mm), so that the maximum formable size of the EBSM equipment can be phi 1500mm multiplied by 1500 mm. The device still can be a plurality of at 360 degrees equipartitions of annular powder bed to cooperation many spirals are printed, make efficiency higher.

Based on the structure, the powder scraping device for the high-temperature printing system has the following characteristics:

(1) the continuous powder scraping and compacting work can be realized under the continuous high-temperature environment, and the working efficiency is improved; (2) the compaction cutter 22 with the gaps has the advantages that the structural form is provided, heat is effectively released, and thermal deformation of the cutter is reduced; (3) the scraper 23 adopts double blades, is thin, has certain deformability when meeting special hard points, and is beneficial to continuously scraping powder, compacting and printing; (4) a scraper 23 is arranged in front of the compacting knife 22 to pre-push the powder uniformly, so that the stress of the compacting knife 22 is reduced; (5) the scraper 23, the compacting plate and other parts have small weight and volume, and are convenient to install, adjust, replace and improve; (6) the compacting cutter 22 is thin in thickness, the thin-wall arc surface is designed with flexibility, the cutter can be retracted when meeting special hard points, the compacting is continuously and uninterruptedly carried out, and a reasonable arc radius forms a certain biting angle, so that the compacting effect is good. (7) The invention has simple structure, convenient disassembly and assembly and replacement, small volume and reduced space of the vacuum chamber, thereby saving the vacuum-pumping time, the vacuum system does not need to be large, and the equipment cost can be greatly reduced; (8) because the invention adopts a special powder scraping and compacting mode, the powder scraping quality is ensured, the compacting effect is good, and the quality of the formed part is increased.