Auxiliary structure for cleaning powder of additive manufacturing part

Abstract

The invention is suitable for the field of laser additive manufacturing, and provides an auxiliary structure for additive manufacturing part powder cleaning, the auxiliary structure comprises a flow guide concave table integrally formed with a part and fixed flow guide micro ribs, the fixed flow guide micro ribs are circumferentially distributed along the periphery of the flow guide concave table, one end of each fixed flow guide micro rib is connected with a cavity, and the other end of each fixed flow guide micro rib is connected with the flow guide concave table to form a splayed shape; according to the method, the size is calculated through a quantitative formula, the flow guide micro ribs are straight right trapezoid cross sections, powder can be guided to be discharged on the premise that the part structure is not weakened, the amount of residual powder can be reduced to 9%-15% of the amount of residual powder without structural parts in cooperation with a traditional physical powder cleaning method, and the powder cleaning efficiency is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of laser additive manufacturing, and particularly relates to an auxiliary structure for cleaning powder from additively manufactured parts. Background Technology

[0002] Existing residual powder cleaning technologies for complex skin lattice parts manufactured using laser powder bed additive manufacturing have the following limitations, failing to meet the requirements for efficient and structurally sound powder cleaning: Adding cleaning holes: This requires designing more cleaning holes for large cavities, which can compromise the structural integrity and mechanical properties of the parts, especially in areas of stress concentration; cleaning holes that are too small are prone to deformation, failure, or blockage during printing, resulting in limited cleaning effectiveness. Dedicated powder suction equipment solution: Based on the principle of vacuum adsorption, it is equipped with a movable powder suction head and a powder classification and storage bin. However, the size and rigid movement path of the powder suction head cannot effectively reach the deep cavities, dead corners and complex flow channels of the parts, resulting in incomplete cleaning of residual powder. Integrated vibration and air blowing system solution: The part is placed in the working chamber and the powder is removed by mechanical vibration, ultrasonic vibration or compressed gas blowing. It is only effective for the external part and simple internal structure. For complex internal cavities with multiple detours, it is difficult to evenly transfer energy to all dead corners. In addition, if the compressed gas flow rate is too high, it will damage the skin structure, and if the flow rate is too low, the powder removal cannot be completed. Intelligent powder cleaning device solution: expands the cleaning range by rotating the air blowing structure or multi-layer adsorption hood, but in essence, it still applies force from the outside of the parts, which cannot optimize the flow and discharge path of powder in the complex cavity and cannot fundamentally solve the problem of residual powder retention. Therefore, an auxiliary structure for cleaning powder from additively manufactured parts is needed to solve the above problems. Summary of the Invention

[0003] The purpose of this invention is to provide an auxiliary structure for cleaning powder from additively manufactured parts, in order to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: An auxiliary structure for powder cleaning of additively manufactured parts includes a flow-guiding recess and fixed flow-guiding microribs integrally formed with the part. The fixed flow-guiding microribs are distributed circumferentially around the periphery of the flow-guiding recess, with one end connected to the cavity of the part and the other end connected to the flow-guiding recess in a figure-eight shape. The size of the flow-guiding recess is determined by the diameter of the powder cleaning hole, the cavity space, the complex features of the cavity, and the powder properties to meet the powder cleaning requirements. The fixed flow-guiding microribs are straight structures with a right-angled trapezoidal cross-section. Their size is determined by the width-to-depth ratio of the cavity, the size of the flow-guiding recess, and the forming capability of the process to meet the requirements of connecting the cavity and the flow-guiding recess without interfering with the overall structure of the part.

[0005] It can achieve one-piece molding of structure and parts, avoiding damage to the part structure by additional openings. At the same time, it can accurately match the cavity parameters through quantitative formulas to ensure that the flow guiding structure is adapted to complex cavities and guides the powder to be discharged efficiently.

[0006] A further technical solution is to use the cavity complexity coefficient to define the complex features of the cavity. measure, ,in It is the volume of the cavity's outer envelope (the volume of the cavity enclosed by the smallest cuboid or cylinder). This refers to the actual volume of the cavity; The corresponding cavities are divided into three levels: simple cavity (smooth-walled straight cylinder). Medium-complex cavity (with a few ribs, steps, or a separate internal cavity) Complex cavities (with dense honeycomb / lattice structures, multiple independent internal cavities, or complex flow channels) ; This classification can objectively reflect the impact of the internal characteristics of the cavity on the risk of thermal stress concentration and powder retention, providing a precise basis for the size design of the flow guide concave platform and fixed flow guide microribs, and avoiding poor powder cleaning effect or structural failure due to improper parameter adaptation.

[0007] A further technical solution is that the powder property is the powder angle of repose. The inclination angle of the inclined surface of the guide concave platform, Horizontal projection of the width of the concave platform slope ( For the concave platform with a large diameter, (Diameter of the powder cleaning hole) and depth of the recess. .

[0008] In a further technical solution, the inclination angle between the trapezoidal inclined surface of the fixed flow guide microrib cross-section and the height direction is 8~15°. ( (The inclination angle of the cross-section of the flow guiding microrib is 8~15°). This shape can significantly reduce the area where powder remains at the root of the guide ribs, reduce the risk of powder adhesion, and further optimize the powder flow path, improve powder cleaning efficiency, and avoid the problem of powder accumulation in traditional straight rib structures.

[0009] A further technical solution is that the aspect ratio of the cavity is... ( The height of the cavity. (Waistway width), length of fixed flow guide microribs ,high ,in , according to Sure: hour , hour , hour ; This design can ensure the reliability of the microrib structure while avoiding the risk of printing deformation caused by the "tall and thin" ribs, ensuring the dimensional accuracy of the parts after molding, and adapting to the height requirements of complex cavities for the microribs.

[0010] A further technical solution is that the root width of the fixed flow guiding microrib... ( This is the minimum size required for reliable forming in the process, typically 0.5~1.0 mm for SLM (Simplified Molding Machine). When the height is relatively high, its aspect ratio is set to 1:1 to 3:1; This design can ensure the reliability of the microrib structure while avoiding the risk of printing deformation caused by the "tall and thin" ribs, ensuring the dimensional accuracy of the parts after molding, and adapting to the height requirements of complex cavities for the microribs.

[0011] In a further technical solution, the number of fixed flow guiding microribs is preferably 4, which are distributed circumferentially around the periphery of the flow guiding concave platform. The fixed flow guiding microribs are outward along the inclined surface of the trapezoid and can be adjusted according to the cavity size to achieve uniform constraint on the powder flow path. This quantity setting enables uniform constraint on the powder flow path, preventing residual powder from accumulating in localized areas where there is no guiding effect, while also avoiding excessive guide ribs occupying cavity space or increasing printing complexity.

[0012] A further technical solution is that this structure is used in conjunction with traditional physical powder cleaning methods, including mechanical vibration powder cleaning, ultrasonic vibration powder cleaning, and compressed gas blowing powder. This combination method can make full use of the basic function of traditional powder cleaning equipment, and combine the flow guiding advantages of the auxiliary structure of this invention to achieve synergistic powder cleaning of "external force + internal flow guiding", which significantly improves powder cleaning efficiency and reduces residual powder.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention solves the problem of structural damage caused by adding powder cleaning holes in traditional methods: the auxiliary structure is integrally formed with the part, and the dimensions are precisely designed by formula, eliminating the need to open a large number of additional powder cleaning holes, and does not significantly weaken the structural integrity and mechanical properties of the part; at the same time, the guide recess can guide the powder to accumulate and be discharged in the dead corners inside multiple complex cavities, and the powder cleaning efficiency is significantly improved compared with the traditional hole opening solution. This invention solves the problem of traditional external cleaning equipment reaching blind spots: fixed guide ribs are used to... , The quantitative design, with one end connected to the cavity and the other end connected to the guide platform in a figure-eight shape, can actively constrain the powder flow path and optimize the flow and discharge path of powder in complex cavities; it solves the problem that dedicated powder suction equipment and vibration blowing system cannot reach dead corners, and the residual powder retention rate is greatly reduced. This invention solves the problems of traditional vibration blowing systems damaging the structure or being ineffective at removing powder: by... Value and Value quantification design parameters, such as according to Value adjustment ,according to Value determined It can accurately match the powder cleaning requirements with structural strength; when used with compressed gas to blow powder, the powder cleaning can be completed through the flow guiding structure without excessive flow, avoiding damage to the skin structure, and avoiding the situation of ineffective powder cleaning at low flow, thus balancing the powder cleaning effect and structural protection.

[0014] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0015] Figure 1 This is a cross-sectional view of the part of the present invention; Figure 2 This is a schematic diagram of the reinforced structure of the powder-clearing hole 1 in this invention; Figure 3 This is a cross-sectional view of the powder cleaning hole 1 and the powder cleaning recess of the present invention; Figure 4 This is a schematic diagram of the cross-section of the guide rib of the powder clearing hole 1 in this invention; Figure 5 This is a schematic diagram of the internal reinforcement structure of the powder-cleaning hole 16 of the present invention; Figure 6 This is a cross-sectional view of the powder cleaning hole 16 of the present invention. Figure 7 This is a schematic diagram of the cross-section of the guide rib of the powder clearing hole 16 of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0018] Example 1 like Figures 1-7As shown, this embodiment of the invention provides an auxiliary structure for powder cleaning of additively manufactured parts, including a No. 3 flow-guiding recess and Nos. 2, 5, 6, and 7 fixed flow-guiding microribs integrally formed with the part; the fixed flow-guiding microribs are distributed circumferentially around the No. 3 flow-guiding recess, with one end connected to the boundary of the No. 1 cavity and the other end connected to the No. 3 flow-guiding recess in a figure-eight shape; the upper part of the part has eight sealed cavities that are interconnected in pairs, forming a medium-complexity cavity structure. The width of the plane containing the powder cleaning hole is 6mm. , Determined according to the process; the powder material is GH4099. ; , , ; No. 3 guide concave platform , , Fixed flow guide ribs No. 2, 5, 6, and 7 , , ( For SLM process, (Take 0.8mm), cross-sectional inclination angle .

[0019] In this embodiment, after the part is printed, compressed gas is used to blow powder. The No. 3 guide concave platform guides the powder to gather in the medium-complex cavity, and the No. 2, 5, 6 and 7 fixed guide microribs constrain the powder flow path to avoid powder stagnation in the dead corners of the cavity. After cleaning the powder, A4 paper is placed under the part to count the amount of residual powder. The amount of residual powder in this area is 12% of that of the part without auxiliary structure, and the upper part of the part is structurally intact without deformation or weakening of mechanical properties. This achieves efficient powder cleaning and structural protection of the medium-complex cavity.

[0020] Example 2 The difference between this embodiment and embodiment 1 is that the lower half of the cavity of the part has a large number of dot matrix structures and a large area of ​​cavity, making it a complex cavity. , , The plane containing the recessed platform at powder cleaning hole No. 16 is wider. The powder material remains GH4099. ; , , (Actually adjusted to 1.5); No. 10 guide concave platform ,, , Fixed flow guide ribs No. 9, 11, 12, and 14 , ,because Relatively high, aspect ratio set to , Cross-sectional inclination angle .

[0021] In this embodiment, the lower half of the cavity of the part has a large number of lattice structures and a large area of ​​cavity, making it a complex cavity. , , The plane containing the recessed platform at powder cleaning hole No. 16 is wider. The powder material remains GH4099. ; , , (Actually adjusted to 1.5); No. 10 guide concave platform ,, , Fixed flow guide ribs No. 9, 11, 12, and 14 , ,because Relatively high, aspect ratio set to , Cross-sectional inclination angle .

[0022] Working principle and usage process of this invention: Model preprocessing and parameter calculation: Obtain the 3D model of the part cavity and measure... (External envelope volume of the cavity) and (Actual volume of the cavity), through calculate Value; measurement (Diameter of the powder cleaning hole), width of the plane containing the recessed platform (to be determined) ), (Cavity height) and (Cavity width), calculation Determined based on the properties of the powder material. (Angle of repose of powder).

[0023] Guide recess size design: through calculate (Horizontal projection of the width of the concave ramp); Passed. Sure (Inclination angle of the concave platform slope); through calculate (Depth of the concave platform) Complete the design of the dimensions of the guide concave platform.

[0024] Design of fixed flow guide microrib dimensions: based on Value determined ( hour , hour , hour ),pass calculate (Proportionality coefficient); through calculate (Height of guide ribs), if If it is too high, adjust the aspect ratio to 1. Sure (Root width) At lower Pick (Minimum forming size for SLM process, typically taken as follows) );pass Sure (Length of guide ribs); The guide ribs are designed to be straight, with a right-angled trapezoidal cross-section (angle of inclination). The microribs are distributed circumferentially along the concave platform, with a preferred number of 4. The fixed guide microribs are outward along the inclined surface of the trapezoid and can be adjusted according to the cavity size to ensure that one end is connected to the cavity and the other end is connected to the concave platform.

[0025] Integrated part molding: The designed flow-guiding recess and fixed flow-guiding microribs are integrated with the original part model to ensure that they do not interfere with the overall structure of the part. The part is printed by laser powder bed additive manufacturing process to achieve integrated molding of auxiliary structure and part.

[0026] Collaborative powder cleaning operation: After printing, traditional physical powder cleaning methods (mechanical vibration, ultrasonic vibration, or compressed gas blowing) are used; during the cleaning process, the powder enters the cavity under external force, and the fixed guide microribs constrain the powder flow path, guiding the powder to gather on the guide concave platform; the guide concave platform passes through... The sloping design allows the powder to slide towards the cleaning hole, and finally the powder is discharged from the cleaning hole, completing the efficient cleaning of residual powder in the complex cavity.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An auxiliary structure for cleaning powder from additively manufactured parts, comprising a flow-guiding recess integrally formed with the part and fixed flow-guiding microribs, characterized in that: The fixed flow guiding microribs are distributed circumferentially around the flow guiding concave platform, with one end connected to the cavity of the part and the other end connected to the flow guiding concave platform in a figure-eight shape; The dimensions of the guide concave platform are determined by combining the diameter of the powder cleaning hole, the cavity space, the complex features of the cavity, and the powder properties to meet the powder cleaning requirements. The fixed flow guide microrib has a straight structure with a right-angled trapezoidal cross-section. Its dimensions are determined by the width-to-depth ratio of the cavity, the size of the flow guide recess, and the forming capability, so as to meet the requirements of connecting the cavity and the flow guide recess without interfering with the overall structure of the part.

2. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: The complex features of the cavity are described by the cavity complexity coefficient. measure, ,in It is the volume of the cavity's outer envelope (the volume of the cavity enclosed by the smallest cuboid or cylinder). This refers to the actual volume of the cavity; The corresponding cavities are divided into three levels: simple cavity (smooth-walled straight cylinder). Medium-complex cavity (with a few ribs, steps, or a separate internal cavity) Complex cavities (with dense honeycomb / lattice structures, multiple independent internal cavities, or complex flow channels) .

3. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: The powder property is the powder angle of repose. The inclination angle of the inclined surface of the guide concave platform, Horizontal projection of the width of the concave platform slope ( For the concave platform with a large opening diameter, (Diameter of the powder cleaning hole) and depth of the recess. .

4. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: The trapezoidal inclined surface of the fixed flow guide microrib cross section forms an inclination angle of 8~15° with the height direction. ( The inclination angle of the cross-section of the flow guiding microrib is 8~15°.

5. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: The width-to-depth ratio of the cavity ( The height of the cavity, (Waistway width), length of fixed guide microribs ,high ,in , according to Sure: hour , hour , hour .

6. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: The root width of the fixed flow guide microrib ( This is the minimum size required for reliable forming in the process, typically 0.5~1.0 mm for SLM (Simplified Molding Machine). When the height is relatively high, the aspect ratio is set to 1:1 to 3:

1.

7. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: The number of fixed flow guiding microribs is preferably 4, which are distributed circumferentially around the outer periphery of the flow guiding concave platform. The fixed flow guiding microribs are outward along the inclined surface of the trapezoid and can be adjusted according to the cavity size to achieve uniform constraint on the powder flow path.

8. The auxiliary structure for powder cleaning of additive manufacturing parts according to claim 1, characterized in that: This structure is used in conjunction with traditional physical powder cleaning methods, including mechanical vibration powder cleaning, ultrasonic vibration powder cleaning, and compressed gas blowing powder.

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