Powder mixing equipment for three-dimensional printing

Abstract

The utility model discloses powder mixing equipment for three-dimensional printing, which comprises a rotatably arranged powder mixing tank, the powder mixing tank is of a cylindrical structure, a powder mixing cavity is arranged in the powder mixing tank, a plurality of thorns are arranged in the powder mixing cavity, the powder mixing tank is provided with a material port communicated with the powder mixing cavity and is connected with a cover plate, and the cover plate is connected with the powder mixing tank. And a heating device is arranged on the outer side of the powder mixing tank. According to the powder mixing equipment for three-dimensional printing, the structure is simple, powder mixing and powder drying are synchronously carried out, the production efficiency is improved, the problems of printing holes and performance segregation caused by the fact that powder is mixed firstly and then dried are solved, and agglomerated powder is scattered through thorns in the powder mixing cavity, so that the powder is mixed more evenly.

Description

Technical Field

[0001] This utility model relates to the field of 3D printing technology, and in particular to a powder mixing device for three-dimensional printing. Background Technology

[0002] In 3D printing technology, commonly used powder materials include: 304 stainless steel, 316 stainless steel, 17-4PH stainless steel, copper and copper alloy powder, aluminum and aluminum alloy powder, magnesium and magnesium alloy powder, titanium and titanium alloy powder, and other applicable powder materials. In the pre-printing stage, during powder material preparation, the powders needed for printing generally need to be dried and mixed evenly. This is because stored powder materials easily absorb moisture from the air and clump together, causing the following difficulties in subsequent printing processes: 1. Uneven printing of each layer; 2. Excessively high porosity and uneven distribution of the printed green body, severely affecting performance and uniformity; 3. Uneven powder particle size distribution, leading to performance segregation, inconsistent shrinkage rates, uneven product deformation, and product bending deformation. Alternatively, recycled powder can be mixed evenly with new powder to make the powder more uniform. Sometimes, particle size analysis is performed on the recycled powder, and powders of missing particle sizes are added during mixing. Furthermore, some processes involve mixing powders before drying them, which prevents the agglomerated powders from being broken up. Drying typically involves placing the powder in a drying oven, heating it, and maintaining that temperature for a period of time, which can easily cause powder oxidation. This affects subsequent sintering processes, and if the oxidation is severe or the material is highly sensitive to oxidation, sintering may fail, leading to product scrap. Therefore, improvements are needed. Utility Model Content

[0003] The purpose of this invention is to provide a powder mixing device for 3D printing to overcome the shortcomings of the prior art.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] This utility model discloses a powder mixing device for 3D printing, including a powder mixing tank that is rotatably arranged. The powder mixing tank has a cylindrical structure and a built-in powder mixing cavity. Several brambles are arranged inside the powder mixing cavity. The powder mixing tank is provided with a material inlet communicating with the powder mixing cavity and is connected to a cover plate. A heating device is provided on the outside of the powder mixing tank.

[0006] Furthermore, in the powder mixing device for 3D printing described above, the powder mixing tank is disposed on two parallel rotating rollers, and the surface of the powder mixing tank abuts against the surfaces of the two rotating rollers respectively.

[0007] Furthermore, in the aforementioned powder mixing equipment for 3D printing, the bramble has a prismatic structure and is arranged along the axial direction of the powder mixing tank.

[0008] Furthermore, in the aforementioned powder mixing equipment for 3D printing, the heating device is an arc-shaped heating plate, which is coaxially arranged with the powder mixing tank.

[0009] Furthermore, in the powder mixing equipment for 3D printing described above, the powder mixing tank is provided with an air inlet connector and an air outlet connector at both ends.

[0010] Furthermore, in the powder mixing equipment for 3D printing described above, the air inlet and air outlet are respectively disposed in the powder mixing tank via rotary sealing devices.

[0011] Furthermore, in the aforementioned powder mixing equipment for 3D printing, the rotary sealing device includes a mounting base disposed on the powder mixing tank, the air inlet connector and the air outlet connector are respectively rotatably disposed on the mounting base via bearings, and the two ends of the mounting base are respectively provided with skeleton sealing rings fitted onto the corresponding air inlet connector or air outlet connector via end caps.

[0012] Furthermore, in the aforementioned powder mixing device for 3D printing, a first sealing ring is provided between the mounting base and the powder mixing tank, and a second sealing ring is provided between the end cap and the mounting base.

[0013] Furthermore, in the powder mixing device for 3D printing described above, the powder mixing tank is provided with an air inlet pipe and an air outlet pipe respectively connected to the air inlet connector and the air outlet connector, and a filter screen is provided at the end of the air inlet pipe and the air outlet pipe opposite to the end of the corresponding air inlet connector or air outlet connector, and the air inlet pipe and the air outlet pipe are staggered from the wicker.

[0014] Furthermore, in the powder mixing device for 3D printing described above, the opening of the air inlet pipe is arranged facing upwards, and the opening of the air outlet pipe is arranged facing downwards.

[0015] Compared with the prior art, the advantages of this utility model are as follows: The powder mixing equipment for 3D printing described in this utility model has a simple structure, and the powder mixing and drying are carried out simultaneously, which improves production efficiency and avoids the problems of printing holes and performance segregation caused by mixing powder first and then drying powder. The thorns in the powder mixing chamber break up the agglomerated powder, making the powder mix more uniform. Protective gas is introduced through the air inlet and outlet joints to prevent powder oxidation. At the same time, reducing gases such as hydrogen can also be introduced to realize the powder reduction reaction. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 The following is a schematic structural diagram of a powder mixing device for 3D printing in a specific embodiment of the present invention.

[0018] Figure 2 The following is a schematic installation diagram of an air inlet joint and an air outlet joint in a specific embodiment of the present invention. Specific Embodiments

[0019] Next, the technical solutions in the embodiments of the present invention will be described in detail with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0022] Refer Figure 1 and Figure 2 As shown, a powder mixing device for 3D printing includes a rotatably arranged powder mixing tank 1. The powder mixing tank 1 has a cylindrical structure and an internal powder mixing chamber. A number of wicker strips 2 are arranged in the powder mixing chamber. The powder mixing tank 1 is provided with a material port communicating with the powder mixing chamber and is connected with a cover plate 3. A heating device 4 is arranged outside the powder mixing tank 1.

[0023] In this technical solution, the powder mixing tank has a conventional cylindrical structure and is horizontally mounted. It has a conventional inlet and outlet at both ends. The cover plate is attached to the powder mixing tank with bolts or connected to the inlet with hinges and is sealed with conventional gaskets. The powder mixing tank rotates to mix the powder in the mixing chamber, thereby improving the printing quality. During this process, the powder clumps collide with and break up the clumps, improving the uniformity of powder mixing. At the same time, the heating device dries the powder, that is, powder mixing and drying are carried out simultaneously, improving production efficiency.

[0024] For example, see Figure 1 As shown, the powder mixing tank 1 is mounted on two parallel rotating rollers 5, and the surface of the powder mixing tank 1 abuts against the surfaces of the two rotating rollers 5 respectively.

[0025] In this technical solution, the rotating roller is mounted on the frame via conventional bearing seats and driven by a conventional servo motor. The length of the rotating roller is greater than the length of the mixing tank. The bearing seats and transmission chains at both ends do not contact the mixing tank. During the rotation of the two rotating rollers, the mixing tank is driven to rotate by friction.

[0026] For example, see Figure 2 As shown, the bramble 2 has a prism structure and is arranged along the axial direction of the powder mixing tank 1.

[0027] In this technical solution, the wicker twigs are installed and removed from the inner walls of both ends of the powder mixing chamber through conventional threaded connections / welding, etc. The inlet and outlet can be used as operation ports for installing and removing the wicker twigs. The specific installation structure will not be described in detail, as long as it can realize the installation and removal of the wicker twigs. The cross-section of the wicker twigs is a rhomboid structure, which increases the contact area with the powder and the collision force when in contact, thereby breaking up the agglomerated powder and making the powder mix more uniform.

[0028] For example, see Figure 1 As shown, the heating device 4 is an arc-shaped heating plate, which is coaxially arranged with the powder mixing tank 1.

[0029] In this technical solution, the arc-shaped heating plate is an existing structure that can be used directly. It is installed on the outside of the powder mixing tank using conventional mounting brackets. Inside the powder mixing tank, multiple conventional wireless thermocouples and other temperature measuring elements are installed to monitor the temperature of the powder being baked.

[0030] For example, see Figure 1 and Figure 2 As shown, the mixing tank 1 is equipped with an air inlet connector 6 and an air outlet connector 7 at both ends.

[0031] In this technical solution, the air inlet and outlet are connected to the external gas filling device and vacuum / exhaust device through conventional air pipes, respectively. Protective gas is introduced through the air inlet and outlet to prevent powder oxidation. At the same time, reducing gases such as hydrogen can also be introduced to achieve powder reduction reaction. Before actual use, the protective / reducing gas is first introduced into the powder mixing tank for a period of time to ensure that all the air inside is removed before heating and adjusting to the specified speed. During the air removal stage, the speed can be slowed down first to ensure that the air between the powder particles is also removed.

[0032] For example, see Figure 2 As shown, the air inlet connector 6 and the air outlet connector 7 are respectively installed on the powder mixing tank 1 via a rotary sealing device 8.

[0033] In this technical solution, during the rotation of the mixing tank, neither the air inlet nor the air outlet joints rotate, and the corresponding air pipes do not need to rotate, thus avoiding air pipe twisting / knotting.

[0034] For example, see Figure 2 As shown, the rotary sealing device 8 includes a mounting base 81 disposed on the mixing tank 1, an air inlet connector 6 and an air outlet connector 7 are rotatably disposed on the mounting base 81 via bearings 82, and two ends of the mounting base 81 are respectively provided with skeleton sealing rings 84 sleeved on the corresponding air inlet connector 6 or air outlet connector 7 via end caps 83.

[0035] In this technical solution, the outer wall of the powder mixing tank is machined with threaded blind holes. The mounting base is fixed to the outer wall of the powder mixing tank by conventional bolts, etc. The mounting base rotates with the powder mixing tank. Due to the presence of the bearing, the air inlet and outlet joints do not rotate. The end cover and the skeleton sealing ring are existing structures, which ensure the seal between the air inlet and outlet joints and the corresponding mounting bases, and ensure the overall sealing of the powder mixing tank.

[0036] For example, see Figure 2 As shown, a first sealing ring 85 is provided between the mounting base 81 and the powder mixing tank 1, and a second sealing ring 86 is provided between the end cover 83 and the mounting base 81.

[0037] In this technical solution, the first and second sealing rings are conventional O-rings, used to improve the overall sealing performance of the powder mixing tank.

[0038] For example, see Figure 2 As shown, the mixing tank 1 is equipped with an air inlet pipe 9 and an air outlet pipe 10 respectively connected to the air inlet connector 6 and the air outlet connector 7. The end of the air inlet pipe 9 and the air outlet pipe 10 away from the air inlet connector 6 and the air outlet connector 7 is equipped with a filter screen (not shown). The air inlet pipe 9 and the air outlet pipe 10 are staggered from the bramble 2.

[0039] In this technical solution, the air inlet pipe and the air outlet pipe are composed of conventional pipes and pipe joints, etc., and are used to guide the airflow in the powder mixing tank. The ends of the air inlet pipe and the air outlet pipe that are away from the air inlet joint and the air outlet joint are covered with gauze or other filter screens to prevent powder from entering the air inlet pipe and the air outlet pipe. The axial direction of the wicker is offset from the position of the air inlet pipe and the air outlet pipe, that is, the wicker does not interfere with the air inlet pipe and the air outlet pipe during the rotation of the powder mixing tank.

[0040] For example, see Figure 2 As shown, the opening of the air intake pipe 9 faces upward, and the opening of the air outlet pipe 10 faces downward.

[0041] In this technical solution, the protective / reducing gas flows along the opening of the inlet pipe (the end opposite to the inlet connector) towards the top of the mixing tank, gradually squeezing the air downwards and forcing the air to be discharged along the opening of the outlet pipe (the end opposite to the outlet connector). In addition, to avoid dust accumulation at the openings of the inlet and outlet pipes, the end face of the inlet pipe opening is vertically set, that is, the inlet pipe opening is set obliquely upwards, while the outlet pipe opening is turned downwards by elbows or the like.

[0042] In summary, the powder mixing device for 3D printing described in this utility model has a simple structure, performs powder mixing and drying simultaneously, improves production efficiency, and avoids printing holes and performance segregation problems caused by mixing powder first and then drying powder. The thorns in the powder mixing chamber break up the agglomerated powder, making the powder mix more uniform. Protective gas is introduced through the air inlet and outlet joints to prevent powder oxidation. At the same time, reducing gases such as hydrogen can also be introduced to achieve the powder reduction reaction.

[0043] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0044] The above description is only a specific embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. A powder mixing device for 3D printing, characterized in that, The mixture includes a rotating powder mixing tank, which has a cylindrical structure and an internal powder mixing chamber. The powder mixing chamber is provided with several brambles. The powder mixing tank is provided with a material inlet communicating with the powder mixing chamber and is connected to a cover plate. A heating device is provided on the outside of the powder mixing tank.

2. The powder mixing device for 3D printing according to claim 1, characterized in that: The mixing tank is mounted on two parallel rotating rollers, and the surface of the mixing tank abuts against the surfaces of the two rotating rollers respectively.

3. The powder mixing device for 3D printing according to claim 1, characterized in that: The bramble has a prismatic structure and is arranged along the axial direction of the mixing tank.

4. The powder mixing device for three-dimensional printing according to claim 1, characterized in that: The heating device is an arc-shaped heating plate, which is coaxially arranged with the powder mixing tank.

5. The powder mixing device for three-dimensional printing according to claim 1, characterized in that: The mixing tank is equipped with an air inlet connector and an air outlet connector at both ends.

6. The powder mixing device for three-dimensional printing according to claim 5, characterized in that: The air inlet and air outlet are respectively installed in the powder mixing tank via rotary sealing devices.

7. The powder mixing device for three-dimensional printing according to claim 6, characterized in that: The rotary sealing device includes a mounting base disposed on the mixing tank. The air inlet and air outlet are rotatably disposed on the mounting base via bearings. The two ends of the mounting base are respectively provided with skeleton sealing rings fitted onto the corresponding air inlet or air outlet via end caps.

8. The powder mixing device for three-dimensional printing according to claim 7, characterized in that: A first sealing ring is provided between the mounting base and the mixing tank, and a second sealing ring is provided between the end cover and the mounting base.

9. The powder mixing device for three-dimensional printing according to claim 6, characterized in that: The mixing tank is provided with an air inlet pipe and an air outlet pipe respectively connected to the air inlet connector and the air outlet connector. A filter screen is provided at the end of the air inlet pipe and the air outlet pipe opposite to the corresponding air inlet connector or air outlet connector. The air inlet pipe and the air outlet pipe are staggered from the wicker.

10. The powder mixing device for three-dimensional printing according to claim 9, characterized in that: The air inlet pipe has its opening facing upwards, and the air outlet pipe has its opening facing downwards.

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