Powder lifting mechanism, three-dimensional printer, powder lifting method and powder spreading method

Abstract

The present application discloses a powder lifting mechanism, a three-dimensional printer, a powder lifting method, and a powder spreading method. The powder lifting method of the present application lifts the powder by reducing the length of the powder holding chamber adjacent to the printing chamber along the powder spreading direction, and by removing the powder above the powder spreading plane after the first lifting of the powder and performing the second lifting, thereby avoiding the problem of low powder distribution consistency along the width direction caused by the collapse of the powder above the powder spreading plane facing the printing chamber, thereby improving the degree to which the shape of the printed part conforms to the preset shape or the dimensional accuracy of the printed part.

Description

Technical Field

[0001] The present application relates to the field of three-dimensional printing devices, and in particular to a powder lifting mechanism, a three-dimensional printer, a powder lifting method, and a powder spreading method. Background Art

[0002] See also Figure 1 The 3D printer 5 in the prior art includes a container 6, a support 7, a printing mechanism 8 and a powder lifting mechanism 9. The container 6 is arranged along the width direction ( Figure 1Two cavity walls opposite to each other are arranged along the powder spreading direction 2 perpendicular to the width direction, and two cavity walls opposite to each other are arranged along the powder spreading direction 2 perpendicular to the width direction. The four cavity walls enclose a rectangular accommodating cavity 14, and the upper boundary of the accommodating member 6 forms a powder spreading plane 1, which is generally arranged horizontally; the support member 7 is accommodated in the rectangular accommodating cavity 14 and is suitable for rising and falling relative to the accommodating member 6 along the height direction 3; the portion of the accommodating cavity 14 located above the upper surface of the support member 7 forms a printing cavity 15; the printing cavity 15 has a certain width along the width direction and a certain width along the powder spreading direction 2. The printing chamber 15 has a fixed length and a variable depth along the height direction 3, wherein the height direction 3 is perpendicular to the width direction and the powder laying direction 2; the printing chamber 15 exists as the printing working area of ​​the three-dimensional printer 5, and the powder as the structural material is laid layer by layer into the printing chamber 15. Specifically, after each layer of powder is laid, energy is applied to the powder in a specific area of ​​the layer so that the adjacent powders are sintered together and the powder in the specific area of ​​the layer below it is sintered together. After the powder in the specific area is sintered, the support member 7 is lowered by one layer, and the above process is repeated until the printing is completed. After the printing is completed, the printing chamber 15 will accommodate the printed part with a three-dimensional structure formed by the sintering of the powder and the powder body formed by the powder that has not been sintered, wherein the printed part is buried in the powder body. The printing mechanism 8 is used to achieve sintering of the powder in the specific area. In the prior art, the printing mechanism 8 can selectively apply energy to sinter the powder within a specific area, spray a sintering agent onto the powder within the specific area and non-selectively apply energy to sinter the powder within the specific area, or spray a heat-absorbing agent onto the powder outside the specific area and non-selectively apply energy to prevent sintering of the powder outside the specific area while sintering the powder within the specific area. The powder lifting mechanism 9 is used to lift the powder above the powder spreading plane 1. The powder lifted above the powder spreading plane 1 is suitable for being laid into the printing cavity 15 along the powder spreading direction 2. The powder lifting mechanism 9 includes a powder container 16, a powder lifting member 17 and a powder moving member 18; the powder container 16 is used to hold powder and is fixedly connected or integrated with the container 6, the upper boundary of the powder container 16 is located on the powder laying plane 1, and the cross section of the powder container 16 perpendicular to the width direction is roughly arc-shaped to form a groove for holding powder, and the powder is transported from the bottom of the groove to the groove; the powder lifting member 17 rotates relative to the powder container 16 around a rotation axis extending along the width direction, and its end away from the rotation axis is always in contact with the inner wall of the powder container 16. The powder lifting member 17 is suitable for extracting powder from the groove, and then rotates clockwise and stops at the first rotation position and the second rotation position; the lower edge of the powder moving member 18 is tangent to the powder laying plane 1, and the powder moving member 18 moves along the powder laying direction 2 or moves away from the powder laying direction 2. The specific process of the powder lifting mechanism 9 lifting the powder to the laying plane 1 is as follows: the powder lifting member 17 extracts at least part of the powder from the groove of the powder container 16 to its upper surface by rotating; then as Figure 1As shown, the powder lifting member 17 continues to rotate clockwise and stops at the first rotation position. At this time, the portion of the groove of the powder containing member 16 between the powder spreading plane 1 and the upper surface of the powder lifting member 17 is filled with powder along the width direction, and part of the powder is lifted above the powder spreading plane 1; then as shown Figure 2 As shown, the powder moving member 18 moves away from the powder spreading direction until it passes over the powder lifting member 17 and removes the powder above the powder spreading plane 1 from the powder lifting member 17 to the groove of the powder receiving member 16. At this time, the powder on the powder lifting member 17 only fills the part between the powder spreading plane 1 and the upper surface of the powder lifting member 17; then as shown in FIG. Figure 3 As shown, the powder lifting member 17 continues to rotate clockwise and stops at the second rotation position. At this time, the upper surface of the powder lifting member 17 is located on the powder spreading plane 1, and the powder lifting mechanism 9 lifts at least part of the powder above the powder spreading plane 1. Figure 4 As shown, in the prior art, the powder moving member 18 moves along the powder spreading direction 2 to spread the powder above the powder spreading plane 1 to the printing chamber 15 .

[0003] However, the applicant has found that, using the above-mentioned prior art, the shape of the printed part does not conform to the preset shape or the dimensional accuracy of the printed part is not satisfactory. Summary of the Invention

[0004] The purpose of this application is to overcome the above-mentioned defects or problems existing in the background technology, and to provide a powder lifting mechanism, a three-dimensional printer, a powder lifting method and a powder spreading method, which can improve the degree to which the shape of the printed part conforms to the preset shape or the dimensional accuracy of the printed part.

[0005] In order to achieve the above purpose, the following technical solution is adopted.

[0006] The first technical solution relates to a powder lifting mechanism for lifting powder to a level above the powder spreading plane so that the powder is suitable for being spread onto the printing chamber of a three-dimensional printer along the powder spreading direction, and is characterized in that it comprises: a powder holding member for holding powder and provided with a first wall adjacent to the printing chamber along the powder spreading direction; a powder lifting member arranged opposite to the first wall, suitable for pushing the powder along the powder spreading direction and successively stopping at a metering position and a powder supplying position, wherein the powder fills the powder holding chamber formed between the powder lifting member and the first wall when the powder lifting member stops at the metering position, and the upper boundary of the powder holding chamber is located on the powder spreading plane; and a powder moving member for removing the powder above the powder spreading plane when the powder lifting member stops at the metering position; The component is also provided with two second walls, the first wall extends along the width direction perpendicular to the powder spreading direction, the two second walls extend from both sides of the first wall opposite to each other along the width direction along the powder spreading direction, and the upper boundaries of the first wall and the second wall are both located on the powder spreading plane; the powder lifting component extends along the width direction, and its upper boundary is located on the powder spreading plane; the powder lifting component, the first wall and the two second walls together form the powder holding chamber; the width range of the printing chamber is within the width range of the powder holding chamber; the powder lifting component is also suitable for returning to the initial position from the powder supply position; the powder moving component moves away from the laying direction to remove the powder above the powder spreading plane.

[0007] The second technical solution is based on the first technical solution, wherein a portion of the second wall adjacent to the first wall is provided with a powder guiding surface that is inclined downward toward the other second wall.

[0008] The third technical solution relates to a three-dimensional printer, which includes the powder lifting mechanism as described in the first or second technical solution.

[0009] The fourth technical solution is based on the third technical solution, and further includes a receiving member and a supporting member; the receiving member is provided with a receiving cavity, the upper boundary of which is located on the powder spreading plane; the supporting member is received in the receiving cavity and is adapted to be lifted and lowered relative to the receiving member in the height direction, and the portion of the receiving cavity located above the upper surface of the supporting member forms the printing cavity; the powder receiving member is fixedly connected or integrally connected to the receiving member (6); the powder moving member is further adapted to move in the powder spreading direction and over the first wall when the powder lifting member is parked at the powder supply position to spread the powder to the printing cavity.

[0010] The fifth technical solution is based on the fourth technical solution, wherein the powder holding chamber no longer receives powder at least from the time when the powder lifting member stops at the metering position until the powder moving member passes over the first wall along the powder spreading direction.

[0011] The sixth technical solution is based on the fourth or fifth technical solution, wherein the number of the powder lifting mechanisms is two, and the two powder lifting mechanisms are arranged on both sides of the accommodating part along the powder spreading direction. The two powder lifting mechanisms share a powder moving part and the powder spreading directions are opposite to each other.

[0012] The seventh technical solution relates to a powder lifting method for lifting powder to a level above the powder spreading plane so that the powder is suitable for being spread along the powder spreading direction to the printing chamber of a three-dimensional printer. The powder lifting method comprises the following steps: S1: adding powder to a powder holding chamber, wherein the powder holding chamber is adjacent to the printing chamber along the powder spreading direction and the upper boundary of the chamber wall is located at the powder spreading plane; S2: reducing the length of the powder holding chamber along the powder spreading direction so that the powder fills the powder holding chamber; S3: removing the powder above the powder holding chamber that is above the powder spreading plane away from the powder spreading direction and ensuring that the removed powder does not fall into the printing chamber; S4: further reducing the length of the powder holding chamber along the powder spreading direction.

[0013] The eighth technical solution relates to a powder spreading method, which is used for a three-dimensional printer as described in the sixth technical solution, wherein the powder moving part reciprocates between two stop positions across the printing chamber, and both stop positions are farther away from the printing chamber than the dosing position of the powder lifting part on the corresponding side; the process of the powder moving part moving from one stop position to another stop position is defined as a stroke; during the powder spreading process, at least one stroke satisfies the following conditions: the powder moving part spreads the powder lifted by one powder lifting mechanism to the printing chamber and removes the powder lifted by another powder lifting mechanism from the powder chamber.

[0014] Compared with the prior art, the above solution has the following beneficial effects:

[0015] After long-term observation, research, and experimentation, the applicant discovered that one of the reasons why the existing technology causes the printed part shape to not match the preset shape or the printed part has poor dimensional accuracy is that the powder does not cover the printing cavity well after being laid into the printing cavity, or the upper surface of part of the powder within the printing cavity is not located on the powder laying plane. A key reason for the problem of the powder not covering the printing cavity well after being laid into the printing cavity or the upper surface of part of the powder within the printing cavity being not located on the powder laying plane is that when the powder lifting member rotates to the second rotational position, the powder distribution consistency along the width direction of the powder above the powder laying plane is not high. The consistency of the powder distribution along the width direction refers to the degree of difference between the volumes of the units when the portion of the powder between the first plane and the second plane is divided into several units along the width direction. The smaller the difference, the higher the consistency, and the larger the difference, the lower the consistency. Here, the first plane and the second plane are the planes where the inner surfaces of the two cavity walls that are opposite to each other along the width direction of the printing cavity are located. A careful analysis revealed that after the powder transfer element removes powder above the powder spreading surface from above the powder lifting element by moving away from the powder spreading direction, the powder distribution consistency along the width of the powder lifting element is very high. However, when the powder lifting element rotates to its second rotational position, the distribution consistency of the powder above the powder spreading surface deteriorates due to the collapse of the surface of the powder above the powder spreading surface facing the print chamber during the lifting process. This collapse is unevenly distributed across the width and not solely along the height direction, and the collapsed powder may also fall into the print chamber. Further analysis reveals that the collapse of the surface of the powder above the powder spreading surface facing the print chamber during the lifting process is primarily due to the fluidity of the powder and the fact that the surface facing the print chamber is defined by the arc-shaped inner surface of the powder receiving element's groove, resulting in a very steep slope relative to the powder spreading surface. In particular, the section where this surface meets the upper surface of the powder receiving element is almost perpendicular to the powder spreading surface.

[0016] In the first technical solution, the volume of the powder holding chamber is reduced by moving the powder lifting member in the powder spreading direction, thereby squeezing the powder in the powder holding chamber and lifting part of the powder above the powder spreading plane. Therefore, whether the powder lifting member moves in the powder spreading direction to the metering position or continues to move to the powder supply position, the slope of the surface facing the printing chamber and the surface away from the printing chamber are continuously increased from zero during the powder lifting process, and are completely determined by the stroke of the powder lifting member. Therefore, it can effectively avoid the collapse of the powder on the surface facing the printing chamber and the surface away from the printing chamber. Since the powder in the powder holding chamber is distributed in a uniform manner along the width direction after the powder moving member removes the powder above the powder spreading plane from above the powder holding chamber, when the powder lifting member reaches the powder supply position, the powder above the powder spreading plane is also distributed in a uniform manner along the width direction. Therefore, it helps to improve the problem that the powder does not cover the printing chamber well after being spread in the printing chamber or the upper surface of part of the powder within the printing chamber is not located on the powder spreading plane. This of course helps to improve the degree to which the shape of the printed part conforms to the preset shape or the dimensional accuracy of the printed part.

[0017] In the first technical solution, since the first wall of the powder container is adjacent to the printing chamber along the powder spreading direction, the powder lifted above the powder spreading plane in the powder container can be conveniently spread over the first wall by the powder moving member to the printing chamber.

[0018] In the first technical solution, the powder in the powder holding chamber is squeezed by moving the powder lifting piece from the initial position along the powder spreading direction to the metering position, so that the powder fills the powder holding chamber and continues to be lifted, and then the powder above the powder spreading plane is removed by the powder moving piece, so that the powder is distributed with high consistency along the width direction before being lifted again (before the powder lifting piece moves from the metering position to the powder supply position).

[0019] In the first technical solution, the powder removal by the powder moving member should be interpreted as ensuring that the removed powder does not fall into the printing chamber.

[0020] In the first technical solution, since the first wall extends along the width direction, and the powder lifting piece is arranged opposite to the first wall and extends along the width direction, when the powder lifting piece moves along the powder spreading direction so that the powder contained in the powder chamber is squeezed along the powder spreading direction, the first wall and the powder lifting piece can apply a uniform extrusion force perpendicular to the width direction to the powder, thereby ensuring high consistency in the distribution of the powder along the width direction when the powder is lifted.

[0021] In the first technical solution, since the two second walls are opposite to each other in the width direction and extend in the powder spreading direction, the powder lifting piece extends in the width direction and the powder lifting piece, the first wall and the two second walls together form a powder holding chamber. Therefore, when the powder lifting piece moves in the powder spreading direction, the powder holding chamber is only compressed in the powder spreading direction and the volume is reduced, which can effectively lift the powder upward.

[0022] In the first technical solution, since the upper boundary of the first wall is located on the powder spreading plane and the upper boundary of the powder lifting piece is also located on the powder spreading plane, the upper boundary of the powder holding chamber can be located on the powder spreading plane. After the powder removing piece removes the powder above the powder spreading plane from above the powder holding chamber, all the powder is in the powder holding chamber and fills the powder holding chamber, so the distribution consistency along the width direction is high.

[0023] The first technical solution defines the width of the printing chamber as falling within the width of the powder holding chamber. This means that the first line segment lies within the second line segment, and both endpoints of the first line segment are spaced apart from the corresponding endpoints of the second line segment. This distance is sufficient to ensure that powder lifted above the powder spreading plane does not collapse within the width of the printing chamber. The first line segment is the projection of the first projection onto the third plane; the second line segment is the projection of the second projection onto the first plane; the first projection is the projection of the printing chamber onto the powder spreading plane; the second projection is the projection of the powder holding chamber onto the powder spreading plane; and the third plane is a plane perpendicular to the powder spreading direction. This limitation is made because, when powder within the powder holding chamber is lifted, its shape at both ends along the width direction is still defined by the inner surfaces of the two second walls. Since the inner surfaces of the two second walls are perpendicular to the width direction, the lifted powder may still collapse at both ends along the width direction. To ensure that this collapse does not affect the powder within the width of the printing chamber and to ensure the uniform distribution of powder within the width of the printing chamber, the width of the printing chamber is defined as falling within the width of the powder holding chamber.

[0024] In the first technical solution, the powder moving part moves away from the powder spreading direction to remove the powder above the powder chamber that is higher than the powder spreading plane. This not only ensures that the removed powder is away from the printing chamber, but also helps to spread the powder above the spreading plane to the printing chamber during the reset stroke (i.e. the stroke moving along the powder spreading direction). Therefore, it can reduce the complexity of the structure, save the cost of the 3D printer, and improve the working efficiency of the 3D printer.

[0025] The second technical solution sets a downward-inclined powder guiding surface so that the powder collapsed at both ends of the powder holding chamber along the width direction can be accommodated on the powder guiding surface, and when the powder lifting piece is reset from the powder supply position to the initial position, the collapsed powder is introduced into the powder holding chamber, thereby effectively recovering the collapsed powder.

[0026] The third and fifth technical solutions adopt the powder lifting mechanism in the first or second technical solution, and therefore have the technical effects of the first to third technical solutions accordingly.

[0027] The fifth technical solution limits the powder holding part to a closed state from the time when the powder lifting part stops at the metering position to the time when the powder moving part passes over the first wall in the powder spreading direction and no longer receives powder. This ensures that when powder is supplied to the powder holding chamber, the powder distribution consistency along the width direction will not be destroyed during the entire process from the time when the powder in the powder holding chamber that is higher than the powder spreading plane is removed by the powder moving part to the time when the powder is spread to the printing chamber due to continued supply of powder to the powder holding chamber.

[0028] The sixth technical solution deploys powder lifting mechanisms on both sides of the accommodating element along the powder spreading direction. By sharing a powder moving element, each stroke of the powder moving element can be effectively utilized. In a single stroke, the powder moving element can not only lay powder from the lifting mechanism adjacent to the starting point into the print chamber, but also remove powder from the lifting mechanism adjacent to the end point. This speeds up the process of laying powder into the print chamber and improves the efficiency of the 3D printer.

[0029] The technical effect of the seventh technical solution is equivalent to that of the first technical solution.

[0030] In the seventh technical solution, the powder above the powder chamber that is higher than the powder laying plane is removed by moving away from the powder laying direction. This not only ensures that the removed powder is away from the printing chamber, but also helps to lay the powder above the laying plane to the printing chamber during the reset stroke (i.e. the stroke moving along the powder laying direction). Therefore, it can reduce the complexity of the structure, save the cost of the 3D printer, and improve the working efficiency of the 3D printer.

[0031] The technical effect of the eighth technical solution is equivalent to that of the sixth technical solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solution of the embodiment, the following briefly introduces the drawings required for use:

[0033] Figure 1 This is a schematic diagram of the state of a 3D printer in the prior art when the powder lifting member rotates to the first rotation position;

[0034] Figure 2 A schematic diagram of a state in which a powder removal component of a 3D printer in the prior art removes powder from a powder-laying surface;

[0035] Figure 3 This is a schematic diagram of the state of a 3D printer in the prior art when the powder lifting member rotates to the second rotation position;

[0036] Figure 4 This is a schematic diagram of the state of a 3D printer in the prior art when a powder transfer unit is spreading powder into a printing chamber;

[0037] Figure 5 A top view of the 3D printer of Example 1;

[0038] Figure 6 for Figure 5 AA sectional view;

[0039] Figure 7 for Figure 5 BB cross-sectional view;

[0040] Figure 8 This is a schematic diagram of the 3D printer of Example 1 in a first state;

[0041] Figure 9 is a schematic diagram of the 3D printer of Example 1 in the second state;

[0042] Figure 10 is a schematic diagram of the 3D printer of Example 1 in the third state;

[0043] Figure 11 is a schematic diagram of the 3D printer of Example 1 in the fourth state;

[0044] Figure 12 is a schematic diagram of the 3D printer of Example 1 in the fifth state;

[0045] Figure 13 A top view of the 3D printer of Example 2;

[0046] Figure 14 This is a schematic diagram of the 3D printer of Example 3 in a first state;

[0047] Figure 15 This is a schematic diagram of the 3D printer of Example 3 in the second state;

[0048] Figure 16 This is a schematic diagram of the 3D printer of Example 3 in the third state;

[0049] Figure 17 This is a schematic diagram of the 3D printer of Example 3 in the fourth state;

[0050] Figure 18 This is a schematic diagram of the 3D printer of Example 3 in the fifth state;

[0051] Figure 19 This is a schematic diagram of the 3D printer of Example 3 in the sixth state;

[0052] Figure 20 This is a schematic diagram of the 3D printer of Example 3 in the seventh state;

[0053] Figure 21 This is a schematic diagram of the 3D printer of Example 3 in the eighth state;

[0054] Figure 22 This is a schematic diagram of the 3D printer of Example 3 in the ninth state.

[0055] Description of main reference numerals:

[0056] 1. Powder-laying plane; 2. Powder-laying direction; 3. Height direction; 4. Width direction; 5. 3D printer; 6. Container; 7. Support member; 8. Printing mechanism; 9. Powder-lifting mechanism; 9a. First powder-lifting mechanism; 9b. Second powder-lifting mechanism; 10. Powder storage member; 11. Powder delivery member; 12. Powder discharge member; 13. Opening and closing member; 14. Container chamber; 15. Printing chamber; 16. Powder storage member; 17. Powder-lifting member; 18. Powder transfer member; 19. First wall; 20. Second wall; 21. Third wall; 22. Powder guide surface; 23. Powder delivery port; 24. Powder discharge port; 25. Powder storage chamber. DETAILED DESCRIPTION

[0057] In the claims and the description, unless otherwise defined, the terms "first", "second" or "third", etc. are intended to distinguish different objects rather than to describe a specific order.

[0058] In the claims and the description, unless otherwise defined, the terms "include", "have" and their variations mean "including but not limited to".

[0059] In the claims and description, unless otherwise specified, the term "fixed connection" should be interpreted as any connection between two objects without any displacement relationship or relative rotation relationship, that is, including non-detachable fixed connection, detachable fixed connection and fixed connection through other devices or elements.

[0060] In the claims and the specification, unless otherwise defined, the term “connected as one body” should be interpreted as two parts with different functions belonging to one object and being inseparable in space.

[0061] In the claims and description, unless otherwise specified, the term "consistency of powder distribution along the width direction" should be interpreted as the degree of difference in volume between the units when the part of the powder between the first plane and the second plane is evenly divided into several units along the width direction. The smaller the error, the higher the consistency, and the larger the error, the lower the consistency; the first plane and the second plane are the planes where the inner surfaces of the two cavity walls that are opposite to each other along the width direction of the printing cavity are located.

[0062] In the claims and description, unless otherwise specified, the term "the width range of the printing chamber is within the width range of the powder holding chamber" should be interpreted as the first line segment being within the second line segment and both end points of the first line segment being at a distance from the end points on the corresponding sides of the second line segment, and the distance should be able to ensure that the powder lifted above the powder spreading plane does not collapse within the width range of the printing chamber; the first line segment is the projection of the first projection on the third plane; the second line segment is the projection of the second projection on the first plane; the first projection is the projection of the printing chamber on the powder spreading plane; the second projection is the projection of the powder holding chamber on the powder spreading plane; and the third plane is a plane perpendicular to the powder spreading direction.

[0063] The technical solutions in the embodiments will be described clearly and completely below with reference to the accompanying drawings.

[0064] Example 1

[0065] See also Figure 5 and Figure 6 , Figure 5 and Figure 6 The 3D printer 5 in the first embodiment is shown. As shown in the figure, the 3D printer 5 in the first embodiment includes a container 6, a support member 7, a printing mechanism 8, a powder lifting mechanism 9, a powder storage member 10, a powder feeding member 11, a powder discharge member 12 and an opening and closing member 13.

[0066] like Figure 5 and Figure 6 As shown, the accommodating part 6 is provided with two cavity walls opposite to each other along the width direction 4, and two cavity walls opposite to each other along the powder spreading direction 2 perpendicular to the width direction 4. The four cavity walls enclose a rectangular accommodating cavity 14. The upper boundary of the accommodating part 6 is located on the powder spreading plane 1, and the powder spreading plane 1 is generally set horizontally.

[0067] like Figure 6As shown, the support member 7 is in a flat plate state. The support member 7 is accommodated in a rectangular accommodating cavity 14 and is suitable for rising and falling relative to the accommodating member 6 along the height direction 3. The support member 7 is in sliding contact with the four cavity walls of the rectangular accommodating cavity 14, and the portion of the accommodating cavity 14 located above the upper surface of the support member 7 forms a printing cavity 15. The printing cavity 15 has a certain width along the width direction 4, a certain length along the powder laying direction 2, and a variable depth along the height direction 3. The printing cavity 15 exists as the printing work area of ​​the three-dimensional printer 5. The powder as the structural material is laid layer by layer into the printing cavity 15. Specifically, after each layer of powder is laid, energy is applied to the powder in a specific area of ​​the layer so that the adjacent powders are sintered together and the powder in the specific area of ​​the layer of powder below it is sintered together. After the powder in the specific area is sintered, the support member 7 is lowered by one layer. The above process is repeated until the printing is completed. After printing is completed, the printing chamber 15 will accommodate the printed part with a three-dimensional structure formed by sintering the powder and the powder body formed by the unsintered powder, wherein the printed part is embedded in the powder body.

[0068] like Figure 5 and Figure 6 As shown, the printing mechanism 8 can selectively apply energy to sinter the powder in a specific area, spray a sintering agent onto the powder in the specific area and non-selectively apply energy to sinter the powder in the specific area, or spray a heat-absorbing agent onto the powder outside the specific area and non-selectively apply energy to prevent the powder outside the specific area from sintering while sintering the powder in the specific area. The printing mechanism 8 can be configured to move relative to the receiving member 6 in the powder spreading direction 2 or away from the powder spreading direction 2.

[0069] like Figure 5 、 Figure 6 and Figure 7 As shown, the powder lifting mechanism 9 includes a powder container 16 , a powder lifting member 17 and a powder moving member 18 .

[0070] like Figure 6 and place Figure 7 As shown, the powder container 16 is fixedly connected or integrated with the accommodating member 6. The powder container 16 is used to contain powder and is provided with a first wall 19, two second walls 20 and a third wall 21. The first wall 19 is adjacent to the printing chamber 15 along the powder spreading direction 2, and the first wall 19 extends along the width direction 4 and is perpendicular to the powder spreading plane 1. The upper boundary of the first wall 19 is located on the powder spreading plane 1. The two second walls 20 extend from both sides of the first wall 19 along the powder spreading direction 2 and are perpendicular to the powder spreading plane 1. As shown in FIG. Figure 7As shown, the portion of the second wall 20 adjacent to the first wall 19 is provided with a powder guiding surface 22 that is inclined downwardly toward the other second wall 20. The upper boundary of the second wall 20 is not higher than the powder laying plane 1. In this embodiment, the upper boundary of the second wall 20 is also located at the powder laying plane 1. In other embodiments, the upper boundary of the second wall 20 is allowed to be slightly lower than the powder laying plane 1. The third wall 21 is parallel to the powder laying plane 1, and the first wall 19 and the two second walls 20 are all erected on the third wall 21. In this embodiment, a powder feeding port 23 and a powder discharge port 24 are provided on the third wall 21. The powder feeding port 23 is closer to the first wall 19 than the powder discharge port 24, and as shown Figure 5 As shown, the powder feeding port 23 and the powder discharging port 24 both extend along the width direction 4 .

[0071] The powder lifting member 17 and the first wall 19 are arranged opposite to each other along the powder spreading direction 2 and extend along the width direction 4. The lower boundary of the powder lifting member 17 abuts against the third wall 21, and the upper boundary of the powder lifting member 17 is located on the powder spreading plane 1. The powder lifting member 17, the first wall 19, the two second walls 20 and the third wall 21 together form a powder holding chamber 25. In some other embodiments, the third wall 21 does not have to be parallel to the powder spreading plane 1. The powder holding chamber 25 only needs to be able to accommodate powder. Figure 5 It can be seen that in this embodiment, the width of the printing chamber 15 is within the width of the powder holding chamber 25. This means that the first line segment is within the second line segment, and both endpoints of the first line segment are at a distance from the endpoints on the corresponding sides of the second line segment. This distance should ensure that the powder lifted above the powder spreading plane does not collapse within the width of the printing chamber. The first line segment is the projection of the first projection on the third plane; the second line segment is the projection of the second projection on the first plane; the first projection is the projection of the printing chamber 15 on the powder spreading plane 1; the second projection is the projection of the powder holding chamber 25 on the powder spreading plane 1; and the third plane is a plane perpendicular to the powder spreading direction 2. The powder lifting member 17 is adapted to move relative to the powder holding member 16 from an initial position along the powder spreading direction 2 and to stop at the metering position and the powder supply position, respectively. Figure 8 It shows the state when the powder lifting member 17 is in the initial position. Figure 9 and Figure 10 It shows the state when the powder lifting member 17 is parked at the metering position. Figure 11 and Figure 12 The figure shows the state when the powder lifting member 17 is parked at the powder supply position. Figure 8 It can be seen that when the powder lifting member 17 is in the initial position, the powder discharge port 24 is blocked and the powder feeding port 23 is open; Figure 10 It can be seen that when the powder lifting member 17 is in the dosing position, the powder discharge port 24 is open to the back of the powder holding chamber 25 and is not connected to the powder holding chamber 25, and the powder feeding port 23 is blocked. Figure 11 and Figure 12It can be seen that when the powder lifting member 17 is in the powder feeding position, the powder feeding port 23 and the powder discharge port 24 are both open to the back of the powder holding chamber 25 and are not connected to the powder holding chamber 25. The powder lifting member 17 is also suitable for moving away from the powder spreading direction 2 from the powder feeding position to the initial position, that is, from Figure 12 The state moves to Figure 9 status.

[0072] The lower boundary of the powder moving member 18 is tangent to the powder spreading plane 1. In this embodiment, the powder moving member 18 is suitable for moving relative to the powder holding member 16 along the powder spreading direction 2 and moving away from the powder spreading direction 2. Specifically, the powder moving member 18 is suitable for moving relative to the powder holding member 16 away from the powder spreading direction 2 when the powder lifting member 17 is parked at the metering position, so as to transfer the powder above the powder holding chamber 25 that is higher than the powder spreading plane 1 to the right side of the powder lifting member 17 (further away from the printing chamber 15). In this embodiment, the powder moving member 18 is also suitable for moving along the powder spreading direction 2 when the powder lifting member 17 is parked at the powder supply position, and passing over the powder lifting member 17 and the first wall 19 to spread the powder above the powder spreading plane 1 to the printing chamber 15. In other words, in this embodiment, the powder moving member 18 not only has the function of removing powder above the laying plane 1, but also has the function of spreading powder above the laying plane 1 to the printing chamber 15.

[0073] like Figure 6 As shown, the powder storage member 10 is a container for storing powder. In some embodiments, the powder storage member 10 is integrated with the accommodating member 6. That is, the portion of the accommodating cavity 14 located below the lower surface of the support member 7 can be used to store powder. Therefore, the powder storage member 10 should not be considered a container spatially separate from the accommodating member 6, but rather a container for storing powder. In other words, as long as the 3D printer 5 has space for storing powder, it should be considered the powder storage member 10.

[0074] like Figure 6 As shown, the powder feeding member 11 is used to convey powder from the powder storage member 10 to the powder holding chamber 25. Specifically, one end of the powder feeding member 11 is connected to the holding chamber of the powder storage member 10 via the powder feeding port 23, and the other end is connected to the powder holding chamber 25. In this embodiment, the powder feeding member 11 uses an Archimedean screw powder feeder to convey powder. In other embodiments, other methods readily conceivable to those skilled in the art may be used to convey powder, for example, by placing the powder feeding member 11 above the powder holding chamber 25 and allowing the powder to fall into the powder holding chamber 25 due to gravity.

[0075] like Figure 6 As shown, one end of the powder discharge member 12 is connected to the powder discharge port 24 on the powder storage member 16 , and the other end is connected to the powder storage member 10 to return the powder discharged from the powder discharge port 24 to the storage cavity of the powder storage member 10 .

[0076] like Figure 6As shown, the opening and closing member 13 is used to open and close the powder delivery to the powder holding chamber 25. In this embodiment, the opening and closing member 13 is mounted on the powder delivery member 11 and is configured as a solenoid valve to open and close the powder delivery member 11. In other embodiments, the opening and closing member 13 can also be other components used to activate and deactivate powder delivery. In this embodiment, the opening and closing member 13 is in the closed state at least from the time the powder lifting member 17 is parked at the metering position until the powder transfer member 18 passes over the first wall in the powder spreading direction 2.

[0077] The 3D printer 5 generally implements a powder lifting function, which is used to lift at least a portion of the powder from the powder holding chamber 25 to the powder spreading plane 1. The powder lifted to the powder spreading plane 1 is suitable for being spread along the powder spreading direction 2 to the printing chamber 15 of the 3D printer 5. The method for implementing powder lifting in the 3D printer 5 in this embodiment is specifically as follows:

[0078] S1: Add powder to the powder chamber 25, see Figure 8 , Figure 8 The 3D printer 5 is in the first state after powder has been added to the powder chamber 25. Specifically, before adding powder to the powder chamber 25, the powder lifting member 17 is in the initial position. The powder feeding port 23 is open and connected to the powder chamber 25, while the powder discharge port 24 is blocked. The opening and closing member 13 is then opened, controlling the powder feeding member 11 to operate, causing the powder stored in the powder storage member 10 to be lifted into the powder chamber 25.

[0079] S2: Reduce the length of the powder chamber 25 along the powder spreading direction 2 so that the powder fills the powder chamber 25; Figure 9 , Figure 9 The three-dimensional printer 5 is in the second state in which the powder lifting member 17 is located at the metering position and the powder holding chamber 25 is filled. Specifically, the powder lifting member 17 is controlled to move from the initial position along the powder spreading direction 2 to the metering position. At this time, the powder holding chamber 25 is filled, and the powder is squeezed by the first wall 19 and the powder lifting member 17 along the powder spreading direction 2, so that at least part of the powder is lifted to exceed the powder spreading plane 1. Of course, at this time, the powder exceeding the powder spreading plane 1 does not have a consistent distribution along the width direction 4. After the powder lifting member 17 reaches the metering position, the opening and closing member 13 should be controlled to close and feed powder to the powder holding chamber 25.

[0080] S3: Remove the powder above the powder chamber 25 that is higher than the powder spreading surface 1 and ensure that the removed powder does not fall into the printing chamber 15; see Figure 10 , Figure 10 The 3D printer 5 is in the third state in which the powder moving member 18 moves away from the powder spreading direction 2 and over the powder lifting member 17. Specifically, the powder moving member 18 is controlled to move away from the powder spreading direction 2 until it passes over the powder lifting member 17, so that the powder above the powder spreading plane 1 is removed to the rear of the powder receiving chamber 25 and falls into the powder discharge member 12 from the opened powder discharge port 24 until it returns to the powder storage member 10.

[0081] S4: further reducing the length of the powder chamber 25 along the powder spreading direction 2; Figure 11 , Figure 11 The three-dimensional printer 5 is in the fourth state in which the powder lifting member 17 is located at the powder supply position. Specifically, the powder lifting member 17 is controlled to continue to move along the powder spreading direction 2 from the metering position to the powder supply position. At this time, the powder is squeezed by the first wall 19 and the powder lifting member 17 along the powder spreading direction 2, and at least part of the powder is lifted to exceed the powder spreading plane 1. In this embodiment, the width range of the printing chamber 15 is within the width range of the powder containing chamber 25. Therefore, the collapse of the powder at both ends along the width direction 4 during the lifting process does not affect the consistency of the powder located above the powder spreading plane 1 along the width direction within the width range of the printing chamber 15.

[0082] Figure 12 The fifth state is also shown after the powder moving member 18 has spread powder into the printing chamber 15 . Specifically, the powder moving member 18 is controlled to move in the powder spreading direction 2 , transferring powder above the powder spreading plane 1 in the powder receiving chamber 25 over the first wall 19 into the printing chamber 15 .

[0083] After that, the 3D printer 5 controls the support member 7 to descend one layer, and controls the powder lifting member 17 to return from the powder feeding position to the initial position. At this time, the powder collapsed at both ends along the width direction is transferred to the powder holding chamber 25 through the powder guide surface 22, thus avoiding powder waste. Then the opening and closing member 13 is controlled to open, and the powder feeding member 11 is controlled to feed powder until it returns to the initial position. Figure 8 The first state is shown.

[0084] The above describes in detail the structure, powder lifting process, and powder spreading process of the 3D printer 5 in this embodiment. It can be seen that the 3D printer 5, powder lifting mechanism 9, and powder lifting method in this embodiment have the following effects:

[0085] In this embodiment, the volume of the powder holding chamber 25 is reduced by moving the powder lifting member 17 along the powder spreading direction 2, thereby squeezing the powder in the powder holding chamber 25 and causing part of the powder to be lifted above the powder spreading plane 1. Therefore, whether the powder lifting member 17 moves along the powder spreading direction 2 to the metering position or continues to move to the powder supply position, during the process of the powder being lifted, the slope of the surface facing the printing chamber 15 and the surface away from the printing chamber 15 are continuously increased from zero, and are completely determined by the stroke of the powder lifting member 17. Therefore, it is possible to effectively avoid the surface facing the printing chamber 15 and the surface away from the printing chamber 15 from being uneven. There is a collapse phenomenon, and since the powder in the powder holding chamber 25 is distributed in a high consistency along the width direction 4 after the powder moving member 18 removes the powder above the powder spreading plane 1 from above the powder holding chamber 25, when the powder lifting member 17 reaches the powder supply position, the powder above the powder spreading plane 1 is also distributed in a high consistency along the width direction 4. Therefore, it helps to improve the problem that the powder does not cover the printing chamber 15 well after being spread to the printing chamber 15 or the upper surface of part of the powder within the printing chamber 15 is not located on the powder spreading plane 1, thereby helping to improve the degree to which the shape of the printed part conforms to the preset shape or the dimensional accuracy of the printed part.

[0086] In this embodiment, since the first wall 19 of the powder holding member 16 is adjacent to the printing chamber 15 along the powder spreading direction 2 , the powder lifted above the powder spreading plane 1 in the powder holding chamber 25 can be conveniently spread over the first wall 19 by the powder moving member 18 to the printing chamber 15 .

[0087] In this embodiment, since the first wall 19 extends along the width direction 4, and the powder lifting member 17 is arranged opposite to the first wall 19 and extends along the width direction 4, when the powder lifting member 17 moves along the powder spreading direction 2 and the powder contained in the powder chamber 25 is squeezed along the powder spreading direction 2, the first wall 19 and the powder lifting member 17 can apply a uniform extrusion force perpendicular to the width direction 4 to the powder, thereby ensuring high consistency in the distribution of the powder along the width direction 4 when the powder is lifted.

[0088] In this embodiment, since the two second walls 20 are opposite to each other along the width direction 4 and extend along the powder spreading direction 2, the powder lifting piece 17 extends along the width direction 4 and the powder lifting piece 17, the first wall 19 and the two second walls 20 form a powder holding chamber 25. Therefore, when the powder lifting piece 17 moves along the powder spreading direction 2, the powder holding chamber 25 is only compressed in the powder spreading direction 2, and can effectively lift the powder upward.

[0089] In this embodiment, the powder in the powder holding chamber 25 is squeezed by moving the powder lifting member 17 from the initial position along the powder spreading direction 2 to the metering position, so that the powder fills the powder holding chamber 25 and continues to be lifted, and then the powder on the powder spreading plane 1 is removed by the powder moving member 18, so that the powder is distributed with high consistency along the width direction before being lifted again (before the powder lifting member 17 moves from the metering position to the powder supply position).

[0090] In this embodiment, since the upper boundary of the first wall 19 is located on the powder spreading plane 1 and the upper boundary of the powder lifting member 17 is also located on the powder spreading plane 1, the upper boundary of the powder holding chamber 25 can be located on the powder spreading plane 1. After the powder moving member 18 removes the powder above the powder spreading plane 1 from above the powder holding chamber 25, all the powder is in the powder holding chamber 25 and fills the powder holding chamber 25, so the distribution consistency along the width direction 4 is high.

[0091] In this embodiment, since the powder moving member 18 moves away from the powder spreading direction 2 to remove the powder above the powder spreading plane 1 from above the powder holding chamber 25, it can ensure that the removed powder does not fall into the printing chamber 15. Under the premise of ensuring that the distribution consistency of the powder above the powder spreading plane 1 along the width direction 4 is high, it can improve the problem in the prior art that the powder does not cover the printing chamber 15 well after being spread to the printing chamber 15, or the upper surface of some powder within the printing chamber 15 is not located on the powder spreading plane 1.

[0092] In this embodiment, since the width range of the printing chamber 15 is within the width range of the powder holding chamber 25, collapse within the width range of the printing chamber 25 can be avoided, thereby ensuring the consistency of the distribution of powder within the width range of the printing chamber 15 along the width direction 4.

[0093] In this embodiment, a downwardly inclined powder guiding surface 22 is provided so that the powder collapsed at both ends of the powder holding chamber 25 along the width direction can be accommodated on the powder guiding surface 22, and when the powder lifting member 17 is reset from the powder supply position to the initial position, the part of the collapsed powder is introduced into the powder holding chamber 25, thereby effectively recovering the collapsed powder.

[0094] In this embodiment, the powder moving member 18 can not only remove the powder above the powder chamber 25 that is higher than the powder spreading plane 1, but also realize the powder spreading function, thereby reducing the structural complexity, saving the cost of the 3D printer 5, and improving the working efficiency of the 3D printer 5.

[0095] In this embodiment, the opening and closing member 13 is in a closed state from the time when the powder lifting member 17 stops at the metering position until the powder moving member 18 passes over the first wall 19 along the powder spreading direction 2, which can ensure that when powder is supplied to the powder holding chamber 25, the powder distribution consistency along the width direction will not be destroyed during the entire process from the time when the powder in the powder holding chamber 25 that is higher than the powder spreading plane 1 is removed by the powder moving member 18 to the time when the powder is spread on the printing chamber 15.

[0096] In this embodiment, the powder discharge port 24 and the powder discharge member 12 are provided to recover the powder removed from above the powder containing chamber 25 , which is beneficial to cleaning and environmental protection.

[0097] In this embodiment, the powder feeding port 23 extends along the width direction 4 , which is beneficial for the powder feeding member 11 to distribute the powder in the powder containing cavity 25 along the width direction 4 when the powder is supplied.

[0098] Example 2

[0099] See also Figure 13 In the second embodiment, the powder removal member 18 moves along the width direction 4 to remove powder from the powder holding chamber 25 that is above the powder spreading plane 1. This prevents powder from falling into the printing chamber 15 and ensures a consistent distribution of powder above the powder spreading plane 1 along the width direction 4 for spreading. However, in the second embodiment, a powder spreading member (not shown) is also required. By moving the powder spreading member along the powder spreading direction, powder from the powder holding chamber 25 that is above the powder spreading plane 1 is spread into the printing chamber 15. The remaining structures of the second embodiment are the same as those of the first embodiment.

[0100] Example 3

[0101] See also Figure 14 , different from the first embodiment, the three-dimensional printer 5 of the third embodiment includes two powder lifting mechanisms 9, which are respectively a first powder lifting mechanism 9a and a second powder lifting mechanism 9b, which are respectively arranged on both sides of the accommodating part 6 along the powder spreading direction 2. And the first powder lifting mechanism 9a and the second powder lifting mechanism 9b share a powder moving part 18. Of course, based on the principle of action, it can be known that the powder spreading direction 2 of the first powder lifting mechanism 9a is to the right (not marked in the figure), and the powder spreading direction 2 of the second powder lifting mechanism 9b is to the left. In the third embodiment, each powder lifting mechanism 9 corresponds to a powder storage part 10, a powder feeding part 11, a powder discharge part 12 and an opening and closing part 13. The opening and closing part 13 is also configured to be in a closed state from the time when the powder lifting part 17 in the corresponding powder lifting mechanism 9 is parked at the metering position until the powder moving part 18 passes over the first wall 19 along the powder spreading direction 2. In the third embodiment, the powder moving member 18 reciprocates between a first stop position and a second stop position across the printing chamber 15. Both the first stop position and the second stop position are further away from the printing chamber 15 than the dosing position of the powder lifting member 17 of the powder lifting mechanism 9 on the corresponding side. The other structures of the third embodiment are the same as those of the first embodiment.

[0102] Assume that the left parking position of the powder moving member 18 (the parking position close to the first powder lifting mechanism 9a) is the first parking position, and the right parking position (the parking position close to the second powder lifting mechanism 9b) is the second parking position. The process of the powder moving member 18 moving from one parking position to another is defined as a stroke; during the powder spreading process, at least one stroke satisfies the following conditions: the powder moving member 18 spreads the powder raised by one powder lifting mechanism 9 into the printing chamber 15 and removes the powder raised by another powder lifting mechanism 9 from the powder holding chamber 25. Specifically, Figures 14 to 22 The powder spreading process of the 3D printer 5 of the third embodiment is shown and briefly described below. For detailed descriptions, please refer to the corresponding parts of the first embodiment:

[0103] In the initial state, the powder lifting member 17 of the first powder lifting mechanism 9a and the powder lifting mechanism 17 of the second powder lifting mechanism 9b are both in the initial position;

[0104] The first step: The powder feeding parts 11 of the two powder lifting mechanisms 9 respectively feed powder to the respective powder containing chambers 25 until the powder is fed to the respective powder containing chambers 25. Figure 14 The first state shown;

[0105] Step 2: The powder lifting member 17 of the second powder lifting mechanism 9b moves to the dosing position. Figure 15 The second state shown;

[0106] Step 3: The powder moving member 18 moves from the first stop position to the second stop position, and removes the powder above the powder chamber 25 of the second powder lifting mechanism 9b to the Figure 16 The third state shown; the travel of the powder moving member 18 does not meet the conditions;

[0107] Step 4: The powder lifting member 17 of the first powder lifting mechanism 9a moves to the dosing position and the powder lifting member 17 of the second powder lifting mechanism 9b moves to the powder supply position. Figure 17 The fourth state shown;

[0108] Step 5: The powder moving member 18 moves from the second stop position to the first stop position, spreads the powder above the powder holding chamber 25 of the second powder lifting mechanism 9b to the printing chamber 15, and removes the powder above the powder holding chamber 25 of the first powder lifting mechanism 9a to the printing chamber 15. Figure 18 The fifth state shown; the stroke of the powder moving member 18 meets the conditions;

[0109] Step 6: The powder lifting member 17 of the first powder lifting mechanism 9a moves to the powder feeding position and the powder lifting member 17 of the second powder lifting mechanism 9b is reset to the initial position, the powder feeding member 11 corresponding to the second powder lifting mechanism 9b feeds powder to the powder holding chamber 25 of the second powder lifting mechanism 9b, and the support member 7 is lowered one layer to Figure 19 The sixth state shown;

[0110] Step 7: The powder lifting member 17 of the second powder lifting mechanism 9b moves to the dosing position. Figure 20 The seventh state shown;

[0111] Step 8: The powder moving member 18 moves from the first stop position to the second stop position, spreading the powder above the powder holding chamber 25 of the first powder lifting mechanism 9a to the printing chamber 15, and removing the powder above the powder holding chamber 25 of the second powder lifting mechanism 9b to the printing chamber 15. Figure 21 The eighth state shown; the stroke of the powder moving member 18 meets the conditions;

[0112] Step 9: The powder lifting member 17 of the second powder lifting mechanism 9b moves to the powder feeding position and the powder lifting member 17 of the first powder lifting mechanism 9a returns to the initial position, the powder feeding member 11 corresponding to the first powder lifting mechanism 9a feeds powder to the powder holding chamber 25 of the first powder lifting mechanism 9a, and the support member 7 descends one level to Figure 22 The ninth state shown;

[0113] Step 10: The powder lifting member 17 of the first powder lifting mechanism 9a moves to the dosing position. Figure 17 The fourth state shown;

[0114] Next, the powder laying of the 3D printer 5 will return to the fifth step and enter a cycle from the fifth step to the tenth step. In each cycle, there are two strokes, and both meet the conditions.

[0115] As can be seen from the description of the third embodiment, by arranging the powder lifting mechanisms 9 on both sides of the accommodating member 6 along the powder spreading direction 2 and by sharing the powder moving member 18, each stroke of the powder moving member 18 can be effectively utilized. In one stroke, the powder moving member 18 can not only complete the task of spreading powder from the powder lifting mechanisms 9 adjacent to the starting point to the printing chamber 15, but also complete the task of removing powder from the powder lifting mechanisms 9 adjacent to the end point. This speeds up the pace of spreading powder to the printing chamber 15 and improves the operating efficiency of the 3D printer 5.

[0116] The above description of the specification and embodiments is used to explain the scope of protection of the present application, but does not constitute a limitation on the scope of protection of the present application.

Claims

1. A powder lifting mechanism (9) for lifting powder to a level above a powder spreading surface so that the powder is suitable for spreading along a powder spreading direction to a printing chamber (15) of a three-dimensional printer (5), characterized by comprising: A powder container (16) for containing powder and provided with a first wall (19) adjacent to the printing chamber (15) along a powder spreading direction; a powder lifting member (17) disposed opposite to the first wall (19), adapted to push the powder in the powder spreading direction and to stop at a metering position and a powder supplying position in sequence, wherein when the powder lifting member is stopped at the metering position, the powder fills a powder holding cavity (25) formed between the powder lifting member and the first wall (19), and the upper boundary of the powder holding cavity (25) is located at the powder spreading plane; and A powder moving member (18) which removes powder on the powder spreading surface when the powder lifting member (17) is parked at the dosing position; The powder container (16) is further provided with two second walls (20), the first wall extending in a width direction perpendicular to the powder spreading direction, the two second walls (20) extending from both sides of the first wall (19) in the powder spreading direction opposite to each other in the width direction, and the upper boundaries of the first wall (19) and the second wall (20) are both located on the powder spreading plane; The powder lifting member (17) extends in the width direction, and its upper boundary is located on the powder spreading plane; the powder lifting member (17), the first wall (19) and the two second walls (20) enclose the powder containing chamber (25); the width range of the printing chamber (15) is located within the width range of the powder containing chamber (25); the powder lifting member (17) is also suitable for returning to the initial position from the powder supply position; The powder moving member (18) moves away from the laying direction to remove powder on the powder laying plane.

2. A powder lifting mechanism (9) according to claim 1, characterized in that: A portion of the second wall (20) adjacent to the first wall (19) is provided with a powder guiding surface (22) that is inclined downwardly toward the other second wall (20).

3. A three-dimensional printer (5), characterized in that: It comprises the powder lifting mechanism (9) as described in claim 1 or 2.

4. A three-dimensional printer (5) as claimed in claim 3, characterized in that: It also includes a receiving member (6) and a supporting member (7); The accommodating member (6) is provided with an accommodating cavity (14), the upper boundary of which is located on the powder spreading plane; The support member (7) is accommodated in the accommodating cavity (14) and is adapted to be lifted and lowered in a height direction relative to the accommodating member (6); a portion of the accommodating cavity (14) located above the upper surface of the support member (7) forms the printing cavity (15); The powder holding member (16) is fixedly connected or integrally connected to the holding member (6); the powder moving member (18) is also adapted to move in a powder spreading direction and over the first wall (19) when the powder lifting member (17) is parked at the powder supply position to spread the powder to the printing chamber (15).

5. A three-dimensional printer (5) as claimed in claim 4, characterized in that: The powder holding chamber (25) no longer receives powder from at least when the powder lifting member (17) stops at the metering position until the powder moving member (18) passes over the first wall (19) in the powder spreading direction.

6. A three-dimensional printer (5) as claimed in claim 4 or 5, characterized in that: There are two powder lifting mechanisms (9), which are arranged on both sides of the accommodating part (6) along the powder spreading direction. The two powder lifting mechanisms (9) share a powder moving part (18) and have opposite powder spreading directions.

7. A powder lifting method for lifting powder to a level above a powder spreading surface so that the powder is suitable for spreading along a powder spreading direction to a printing cavity (15) of a three-dimensional printer (5), characterized in that: The powder lifting method is based on the powder lifting mechanism according to claim 1 or 2 and comprises the following steps: S1: adding powder to the powder holding chamber (25), wherein the powder holding chamber (25) is adjacent to the printing chamber (15) along the powder spreading direction and the upper boundary of the chamber wall is located at the powder spreading plane; S2: reducing the length of the powder holding cavity (25) along the powder spreading direction so that the powder fills the powder holding cavity (25); S3: removing the powder above the powder chamber (25) and above the powder spreading surface in a direction away from the powder spreading direction and ensuring that the removed powder does not fall into the printing chamber (15); S4: further reducing the length of the powder holding chamber (25) along the powder spreading direction.

8. A powder spreading method for a 3D printer (5) as claimed in claim 6, characterized in that: The powder moving member (18) moves back and forth across the printing chamber (15) between two parking positions, both of which are further away from the printing chamber (15) than the metering position of the powder lifting member (17) on the corresponding side; The process of the powder moving member (18) moving from one stop position to another stop position is defined as a stroke; During the powder spreading process, at least one stroke satisfies the following conditions: the powder moving member (18) spreads the powder lifted by one powder lifting mechanism (9) to the printing chamber (15) and removes the powder lifted by another powder lifting mechanism (9) from the powder chamber (25).

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