Multi-material coaxial multi-section collaborative directional powder laying method for ceramic additive manufacturing

Abstract

The invention discloses a multi-material coaxial multi-section collaborative powder laying method for ceramic additive manufacturing, which can realize directional powder laying of a combined ceramic material in a powder bed plane and a three-dimensional space in an additive manufacturing process, and aims at physical property parameters of a ceramic core on the basis of directional powder laying, powder laying of dissimilar materials with specified layer thicknesses among layers and powder laying of different materials in specified areas in the layers. And powder laying of inter-layer and intra-layer dissimilar composite ceramic materials of the powder bed is effectively achieved, and integral printing forming of the mold core is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of 3D printing, and particularly relates to a multi-material coaxial multi-segment collaborative directional powder spreading method for ceramic additive manufacturing. Background Technique

[0002] Additive manufacturing technology, namely 3D printing technology, is a new type of rapid prototyping technology that gradually emerged in the 1980s. Its development has begun to shake the position of traditional manufacturing industries and demonstrated unique advantages in many high-tech industries.

[0003] Due to its high mechanical strength and hardness, excellent chemical stability, and excellent characteristics such as sound, light, electromagnetic, and heat, ceramics are widely used in fields such as chemical engineering, machinery, electronics, aerospace, and biomedicine. Traditional ceramic manufacturing processes usually mix ceramic powders with binders or other additives and form the required shapes through methods such as injection molding, die pressing, tape casting, and gel casting. However, most traditional manufacturing processes require the prior manufacture of molds, resulting in a relatively long overall production cycle and difficulty in rapidly forming ceramic parts with highly complex structures. In addition, due to the extremely high hardness and brittleness of ceramics, if used in subtractive forming methods, on the one hand, it is easy to cause wear of cutting tools, and on the other hand, it may also lead to defects such as cracking of the sample parts. Therefore, applying 3D printing technology to the overall forming manufacturing of ceramic cores is one of the main ways to solve the above problems well.

[0004] However, there are still key technical problems to be solved in ceramic core 3D printing technology. During the manufacturing process of ceramic cores based on investment casting, there are problems such as a single type of powder spreading material, low forming efficiency of complex ceramic cores, and weak performance of single-material ceramic cores in regulating the microstructure of single crystal blades. Therefore, it is necessary to combine multiple powder materials to achieve the overall additive manufacturing forming of ceramic cores and lay special powder materials at key parts of the ceramic cores. However, how to effectively achieve directional powder spreading, powder spreading of different materials with specified layer thicknesses between layers, and powder spreading of different materials in specified regions within a layer to achieve powder spreading of dissimilar composite ceramic materials between layers and within layers of the powder bed and realize the overall printing forming of the core is still a problem to be solved by the existing process. Summary of the Invention

[0005] To solve the above problems, the present invention discloses a multi-material coaxial multi-segment collaborative directional powder spreading method for ceramic additive manufacturing. By controlling the rotation speed of the control motor of the roller powder spreading unit and the powder spreading roller structure and the operation period of the electromagnetic key, combined with the bidirectional reciprocating powder spreading method, as the given rotation speed increases, the powder spreading amount will continuously increase. With different motion control parameters, powder spreading of different materials with different layer thicknesses and region sizes can be achieved.

[0006] The multi-material coaxial multi-segment collaborative directional powder spreading method for ceramic additive manufacturing specifically includes the following steps:

[0007] Step 1: According to the images obtained by slicing the ceramic printing model layer by layer, place ceramic powder materials of different types at the designated parts of each layer of the image. Correspondingly, in the powder bed area, set the types and area sizes of the powder materials to be laid.

[0008] Step 2: In the bins of each powder feeding connector, place the first main conventional ceramic powder material corresponding to most areas of the powder bed. By controlling the electromagnetic key head embedded in the rotating roller structure to lift up, and the electromagnetic key head cooperates with the powder spreading roller to lock, let the rotating roller drive the powder spreading roller to spread the first material in the powder feeding connector on the corresponding powder spreading area set in Step 1.

[0009] Step 3: In individual areas where the second or even the third special ceramic material needs to be laid, control the cooperation between the retraction of the electromagnetic key head and the powder spreading roller, so that the rotating roller stops driving the powder spreading roller to rotate and spread powder, and control it to leave an area for laying the special ceramic material.

[0010] Step 4: After completing a one-way powder spreading stroke, clean the excess material in the powder spreading connector; then repeat Step 2. Corresponding to the area for laying the special ceramic powder material, place the second powder material to be laid. According to each section of the shaft in the corresponding powder spreading area, when current passes through the electromagnetic key body, the electromagnetic key head lifts up to lock the rotating roller and the powder spreading roller to form an integral body. Control the motor to drive the rotating roller to control the corresponding powder spreading roller to rotate. In the area corresponding to laying the second ceramic powder material, set the powder spreading parameters for covering the corresponding area. During the return process, when reaching the area where the second ceramic powder material needs to be laid, lay the second ceramic powder material.

[0011] Step 5: And so on, through Steps 2, 3, and 4, perform two-way repeated powder spreading to achieve the powder spreading method of two or three or more materials, and evenly cover each layer of the powder bed area.

[0012] Step 6: The powder feeding connector 02 can, according to the above steps, achieve the laying of any powder material in any area of the powder bed corresponding to the powder feeding connector segments 1, 2, 3, and 4.

[0013] Step 7: After the above 6 steps, print the shape of each layer slice of the model on the surface of the powder bed where the ceramic composite material is laid in each layer. Through layer-by-layer stacking, a complete multi-material complex ceramic model required is formed.

[0014] Further, the powder feeding connector is arranged above the powder bed. The powder feeding connector has n material sections. A powder spreading roller structure is arranged below the powder feeding connector. The roller rotating structure is composed of n single-section powder spreading rollers. The single-section powder spreading rollers at different positions respectively correspond to different material sections of the powder feeding connector; each single-section powder spreading roller is provided with an electromagnetic key and is sleeved with a powder spreading roller on the surface. The electromagnetic keys of each section of the shaft receive alternating current, and the rotation of the single-section powder spreading roller in the forward and reverse directions is controlled by the control motor. Combined with the reciprocating motion mode, multi-material coaxial multi-section collaborative directional uniform powder spreading is realized.

[0015] Further, by controlling the rotation speeds of the control motor and the rotating roller, and the operation period of the electromagnetic key, combined with the reciprocating powder spreading means, single-layer powder spreading control of the multi-material coaxial multi-section collaborative directional area can be realized; each of the electromagnetic keys includes an electromagnetic key head, a spring bayonet, an electromagnet and a wiring terminal; when the current of the wiring terminal passes through the electromagnet, the electromagnetic key head pops up, and cooperates with the spring bayonet to lock with the powder spreading roller, and the rotating roller drives the powder spreading roller to rotate synchronously with the rotating roller.

[0016] Further, by changing the intermittent period t2 and the working time t1 of the control current of the electromagnetic key of each shaft section, the working period of the electromagnetic key is controlled, so that the powder spreading rollers of each shaft section can achieve different rotation speeds and the start and stop of each section of the rotating roller, and various ceramic powder materials can be laid with the specified ceramic powder materials at any position on any layer of the powder bed.

[0017] Since the particle sizes of different ceramic powders are different, the powder leakage amounts are also different when the rotating roller rotates by the same angle. Therefore, by matching different powder spreading rollers with different parameters such as rotation speed and powder spreading movement speed, the layer thickness can be further controlled in cooperation with the roller leveling, and the powder spreading uniform layer thickness and surface accuracy of various ceramic materials on the same layer plane of the powder bed can be realized.

[0018] The beneficial effects of the present invention are realized through a novel powder spreading structure and a printing method, which mainly include a multi-material ceramic powder storage unit, a roller powder spreading unit, a powder bed and a ceramic printing head. The four parts together constitute a ceramic printing device. The multi-material powder feeding storage unit has multiple material positions. The powder feeding connector has stamping powder discharging, and there is a discharging opening on one side. When each storage unit is full of materials, for the powder spreading roller, for each section of the ceramic material to be contained, the discharging port is opened in a timely manner, and the ceramic material automatically falls into the umbrella-shaped storage groove of the powder spreading roller, filling the entire powder spreading roller compartment with different ceramic powder materials. By controlling the rotation speeds of the control motor of the roller powder spreading unit and the powder spreading roller structure, and the operation period of the electromagnetic key, combined with the bidirectional reciprocating powder spreading mode, as the given rotation speed increases, the powder spreading amount will continuously increase. By cooperating with different motion control parameters, powder spreading with different layer thicknesses and area sizes of multiple materials can be realized. Description of the Drawings

[0019] Figure 1 Schematic diagram of a multi-material coaxial multi-segment collaborative directional powder spreading method and device for ceramic additive manufacturing according to the present invention. There are a powder bed 01, a powder feeding connector 02, a connecting slide plate 03, a module motor 04, a vertical frame 05, a platform lifting motor 06, a vertical frame support 07, a powder collection box 08, and two side modules 09.

[0020] Figure 2 Schematic diagram of the powder feeding connector.

[0021] Figure 3 Schematic diagram of a roller powder spreading unit section according to the present invention. There are a bearing installation stop, an umbrella-shaped storage tank, and an internal tooth keyway of the roller powder spreading unit, and the positions of the feeding port and the powder spreading port are indicated.

[0022] Figure 4 Schematic cross-sectional view of the installation of the rotating roller and the roller powder spreading unit. Each section of the roller powder spreading unit corresponds to a material section of the powder feeding connector. There are an electromagnetic key 204, a powder spreading roller 205, and a rotating roller 206.

[0023] Figure 5 Schematic diagram of the electromagnetic key structure. There are an electromagnetic key head 401, a spring bayonet 402, an electromagnet 403, and a wiring terminal 404. The figures show that the electromagnetic key head extends to clamp the internal tooth keyway of the roller powder spreading unit and retracts to disengage from the internal tooth keyway of the powder spreading unit, respectively.

[0024] Figure 6 Schematic diagram of the surface powder spreading effect. There is an effect of uniformly spreading ceramic powders of different materials under the action of the powder spreading roller according to the divided areas.

[0025] Figure 7 Schematic diagram of the electromagnetic key and the control motor current / cycle. Where t1 and t2 are the operating cycles of the current controlling the electromagnetic key. After being energized within the t1 cycle, the electromagnetic key head 401 in the electromagnetic key 204 pops up to connect the powder spreading roller 205 and the rotating roller 206 together. Specific embodiments

[0026] The present invention will be further clarified below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the terms "inner" and "outer" refer to the directions towards or away from the geometric center of a specific component, respectively.

[0027] As Figures 1-5 shown, the multi-material coaxial multi-segment collaborative directional powder spreading method for ceramic additive manufacturing in this embodiment specifically includes the following steps:

[0028] Step 1: According to the images obtained by slicing the ceramic printing model layer by layer, place ceramic powder materials of different types at the specified parts of each layer of image. Correspondingly, in the powder bed 01 area, set the types and area sizes of the powder materials to be laid.

[0029] Step 2: In the bins of each powder feeding connector 02, place the first main conventional ceramic powder material corresponding to most areas of the powder bed 01. Through control, the electromagnetic key head 401 embedded in the rotating roller 206 structure is lifted, and the electromagnetic key head 401 cooperates with the powder spreading roller 205 to lock. Then, the rotating roller 206 drives the powder spreading roller 205 to spread the first material in the powder feeding connector 02 on the corresponding powder spreading area set in Step 1.

[0030] Step 3: In individual areas where the second or even the third special ceramic material needs to be laid, control the electromagnetic key head 401 to retract its cooperation with the powder spreading roller 205, so that the rotating roller 206 stops driving the powder spreading roller 205 to rotate and spread powder, and control it to leave an area for laying the special ceramic material.

[0031] Step 4: After completing a one-way powder spreading stroke, clean the excess material in the powder spreading connector. Then repeat Step 2. For the area where the special ceramic powder material needs to be laid, place the second powder material required to be laid. According to each section of the shaft in the corresponding powder spreading area, current passes through the electromagnetic key body (204), the electromagnetic key head 401 is lifted to lock the rotating roller 206 and the powder spreading roller 205 to form an integral body. Control the motor 202 to drive the rotating roller 206 to control the corresponding powder spreading roller 205 to rotate. In the area where the second ceramic powder is to be laid, set the powder spreading parameters for covering the corresponding area. During the reverse return process, when reaching the area where the second ceramic powder needs to be laid, perform the laying of the second ceramic powder.

[0032] Step 5: And so on. Through Steps (2), (3), and (4), perform two-way repeated powder spreading to achieve the powder spreading method for two or three or more materials, and evenly cover each area of the powder bed 01 of each layer.

[0033] Step 6: The powder feeding connector 02 can, according to the above steps, achieve the laying of any powder material in any area of the powder bed 01 corresponding to the segments 1, 2, 3, and 4 of the powder feeding connector.

[0034] Step 7: After the above six steps, print the shape of each layer slice of the model on the surface of the powder bed where the ceramic composite material is laid in each layer. Through layer-by-layer stacking, a complete multi-material complex ceramic model required is formed.

[0035] Figure 5As shown, by controlling the rotational speeds of the motor 202 and the rotating roller 206, and the operating cycle of the electromagnetic key 204, combined with the reciprocating powder spreading means, single-layer powder spreading control in a multi-material coaxial multi-segment collaborative directional area can be achieved. As the rotational speed given by the control of the motor 202 increases, the powder spreading amount will continuously increase. By coordinating different control parameters, different ceramic powder materials with different layer thicknesses can be laid on the powder bed 01. In each shaft segment of the multi-segment shaft, an electromagnetic key 204 is arranged, and the electromagnetic key 204 of each shaft segment can receive alternating current.

[0036] Figure 6 As shown in the structure of the electromagnetic key (204), when the current at the wiring terminal 404 passes through the electromagnet 403, the electromagnetic key head 401 pops up, and cooperates with the spring bayonet 402 to lock with the powder spreading roller 205. The rotating roller 206 drives the powder spreading roller 205 to rotate synchronously with the rotating roller 206, and spreads the ceramic powder in each powder spreading roller 205 in the corresponding area, achieving the powder spreading effect of multi-materials in the specified area as a whole.

[0037] Figure 7 As shown, set the intermittent period t2 and the working time t1 of the control current matching the electromagnetic key 204 of each shaft segment, and control the working cycle of the electromagnetic key 204, so that the powder spreading rollers 205 of each shaft segment can achieve different rotational speeds and the start-stop duration of each rotating roller 206.

[0038] At the same time, due to the different particle sizes of different ceramic powders, the powder leakage amount is different when the rotating roller 206 rotates by the same angle. Therefore, by matching different powder spreading rollers 203 with different parameters such as rotational speed and powder spreading movement speed, the layer thickness can be further controlled in cooperation with the roller leveling, and the uniform layer thickness and surface accuracy of powder spreading of multiple ceramic materials on the same layer plane of the powder bed can be achieved.

[0039] Through the powder spreading effect of multi-materials with a single layer thickness, combined with the nozzle printing technology, the overall forming of a multi-material sand mold is realized. Finally, through layer-by-layer stacking, the additive manufacturing of a complex multi-material ceramic core is achieved.

[0040] Figure 4 As shown, by controlling the rotational speeds of the motor 202 and the rotating roller 206, and the operating cycle of the electromagnetic key 204, combined with the reciprocating powder spreading means, single-layer powder spreading control in a multi-material coaxial multi-segment collaborative directional area can be achieved. As the rotational speed given by the control of the motor 202 increases, the powder spreading amount will continuously increase. By coordinating different control parameters, different ceramic powder materials with different layer thicknesses can be laid on the powder bed 01. In each shaft segment of the multi-segment shaft, an electromagnetic key 204 is arranged, and the electromagnetic key 204 of each shaft segment can receive alternating current.

[0041] Figure 5The structure of the electromagnetic key 204 is shown. When the current of the wiring terminal 404 passes through the electromagnet 403, the electromagnetic key head 401 is lifted, and it cooperates with the spring bayonet 402 to lock with the powder spreading roller 205. The rotating roller 206 drives the powder spreading roller 205 to rotate synchronously with the rotating roller 206, and the ceramic powder in each section of the powder spreading roller 205 is spread on the corresponding area, and the powder spreading effect of multiple materials in the specified area is realized as a whole.

[0042] An example of single-layer powder spreading is as Figure 6 shown. There are 1-4 sections of powder spreading rollers 205, among which the powder spreading rollers 1 and 3, and the powder spreading rollers 2 and 4 need to be different materials in different material sections, and they are combined and linked to move forward positively. Powder is spread in the corresponding area, and the powder bed 01 is set to an area of 4M×5N. By setting the current signal, the electromagnetic key 204 of the corresponding powder spreading roller 205 is controlled to extend, and the powder spreading roller 205 is controlled to rotate rapidly to shake out the powder from the umbrella-shaped powder spreading port for powder spreading. After the corresponding area is filled, the electromagnetic key 204 retracts, cooperates with the stop rotation, and leaves the second material to be laid. When reaching the third area, the above powder spreading operation is repeated. When moving in the reverse direction, the powder feeding connector is at the powder collection box to shake out the excess powder, replace the second powder material, and perform powder spreading in the spaced areas. Finally, the single-layer powder spreading forming effect reaches M rows: zirconium-silicon-zirconium-silicon, aluminum-magnesium-aluminum-magnesium, zirconium-silicon-zirconium-silicon, aluminum-magnesium-aluminum-magnesium, zirconium-silicon-zirconium-silicon; N columns are spaced out in a staggered manner with four columns such as zirconium-aluminum-zirconium-aluminum-zirconium, silicon-magnesium-silicon-magnesium-silicon, zirconium-aluminum-zirconium-aluminum-zirconium, silicon-magnesium-silicon-magnesium-silicon, etc.

[0043] Through the powder spreading effect of multiple materials with a single layer thickness, combined with the nozzle printing technology, the overall forming of the multi-material sand mold is realized. Finally, through layer-by-layer stacking, the additive manufacturing of complex multi-material ceramic cores is realized.

[0044] Figure 7 As shown, the intermittent period t2 and the working time t1 of the control current matching each shaft section of the electromagnetic key 204 are set to control the working cycle of the electromagnetic key 204, so that the powder spreading rollers 205 of each shaft section can achieve different rotation speeds and the start-stop duration of each section of the rotating roller 206.

[0045] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A multi-material coaxial multi-segment collaborative powder laying method for ceramic additive manufacturing, characterized in that: Specifically, it includes the following steps: Step 1: According to the images obtained by slicing the ceramic printing model layer by layer, ceramic powder materials of different types are laid at the specified parts of each layer of image. Correspondingly, in the area of the powder bed (01), the types and area sizes of the laid powder materials are set well. Step 2: In the bins of each powder feeding connector (02), the first main conventional ceramic powder material is laid in most areas of the powder bed (01). Through the control, the electromagnetic key head (401) embedded in the structure of the rotating roller (206) is jacked up. The electromagnetic key head (401) cooperates with and locks the powder spreading roller (205). Then, the rotating roller (206) drives the powder spreading roller (205) to spread the first material in the powder feeding connector (02) in the corresponding powder spreading area set in Step 1. Step 3: In individual areas where the second or even the third special ceramic material needs to be laid, the cooperation between the electromagnetic key head (401) and the powder spreading roller (205) is controlled to be withdrawn, so that the rotating roller (206) stops driving the powder spreading roller (205) to spread powder, and the area for laying the special ceramic material is controlled to be left. Step 4: After completing a one-way powder spreading stroke, the excess material in the powder spreading connector is shaken off. Then, repeat Step 2. For the area corresponding to the laying of the special ceramic powder material, the second powder material to be laid is placed. According to each section of the shaft in the corresponding powder spreading area, the current passes through the electromagnetic key body (204), and the electromagnetic key head (401) is jacked up to lock the rotating roller (206) and the powder spreading roller (205) into one body. The control motor (202) drives the rotating roller (206) to control the corresponding powder spreading roller (205) to rotate. In the area corresponding to the laying of the second ceramic powder material, the powder spreading parameters for covering the corresponding area are set well. During the reverse return process, when reaching the area where the second ceramic powder material needs to be laid, the second ceramic powder material is laid. Step 5: And so on. Through Steps 2, 3, and 4, the powder spreading is carried out in both directions repeatedly to achieve the powder spreading method of two or three or more materials, and the area of each layer of the powder bed (01) is evenly covered. Step 6: The powder feeding connector 02 can, according to the above steps, achieve the laying of any powder material in any area of the powder bed (01) corresponding to the sections 1, 2, 3, and 4 of the powder feeding connector. Step 7: After the above six steps, the shape of each layer slice of the model is printed on the surface of the powder bed where the ceramic composite material is laid in each layer. Through layer-by-layer stacking, the required multi-material complex ceramic model is completely formed.

2. The ceramic additive manufacturing multi-material coaxial multi-segment collaborative powder laying method according to claim 1, wherein: Wherein the powder feeding connector (02) is arranged above the powder bed (01). The powder feeding connector (02) has n material sections. A powder spreading roller structure (203) is arranged below the powder feeding connector (02). The roller rotating structure is composed of n single-section powder spreading rollers (205). The single-section powder spreading rollers (205) at different positions respectively correspond to different material sections of the powder feeding connector (02); each of the single-section powder spreading rollers (205) is provided with an electromagnetic key (204) and is sleeved with a powder spreading roller (205) on the surface. The electromagnetic keys (204) of each section of the shaft receive alternating current, and the forward and reverse rotation of the single-section powder spreading rollers (205) is controlled by the rotation of the control motor (202). Combined with the reciprocating motion mode, multi-material coaxial multi-section collaborative directional uniform powder spreading is realized.

3. The ceramic additive manufacturing multi-material coaxial multi-segment collaborative powder laying method according to claim 2, wherein: By controlling the rotation speeds of the control motor (202) and the rotating roller (206) and the operation period of the electromagnetic key (204), and combining the reciprocating powder spreading means, single-layer powder spreading control of the multi-material coaxial multi-section collaborative directional area can be realized; each of the electromagnetic keys (204) includes an electromagnetic key head (401), a spring bayonet (402), an electromagnet (403) and a wiring terminal (404); when the current of the wiring terminal (404) passes through the electromagnet (403), the electromagnetic key head (401) is jacked up, and cooperates with the spring bayonet (402) to lock with the powder spreading roller (205), and the rotating roller (206) drives the powder spreading roller (205) to rotate synchronously with the rotating roller (206).

4. The coaxial multi-segment collaborative directional powder spreading method for ceramic additive manufacturing according to claim 1, wherein: By changing the intermittent period t2 and the working time t1 of the control current of the electromagnetic key (204) of each shaft section, the working period of the electromagnetic key (204) is controlled, so that the powder spreading rollers (205) of each shaft section can achieve different rotation speeds and the start and stop of each section of the rotating roller (206), and it is realized that various ceramic powder materials can be laid with specified ceramic powder materials at any part of any layer of the powder bed (01).

Images