Mixing device of small amount of metal powder for selective laser melting
By designing a mixing device based on the principle of centrifugal off-axis, the problem of difficulty in efficiently mixing a small amount of metal powder in the prior art is solved, and three-dimensional and efficient mixing is achieved, which improves powder utilization and printing effect and shortens the development cycle of new materials.
Patent Information
- Application Number
- CN202421638144.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-11
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-07-11
AI Technical Summary
It is difficult to efficiently mix a small amount of metal powder in the prior art, and the existing equipment has a great impact on the spherical morphology of the powder, affecting the printing effect.
A mixing device based on the centrifugal off-axis principle is designed, including a powder mixing bottle, a piston mechanism, a clamping mechanism and a driving mechanism. The reverse rotation and alternating rotation of the powder mixing bottle are realized through coordinated driving to achieve three-dimensional efficient mixing.
The mixing efficiency and powder utilization rate of a small amount of metal powder are improved, the development cycle of new materials is shortened, the R&D costs are reduced, the spherical morphology of the powder is improved, and the printing effect is improved.
Smart Images
Figure CN223028475U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of additive manufacturing, and particularly relates to a mixing device for a small amount of metal powder for selective laser melting. Background Art
[0002] Additive manufacturing technology is an advanced manufacturing technology with distinct characteristics such as digital manufacturing, high flexibility and adaptability, direct CAD model drive, rapidity, and a rich variety of material types. Due to its unrestricted by the complexity of part shapes and the absence of any tooling and molds, its application scope is very wide. As one of the additive manufacturing technologies, the basic process of selective laser sintering is as follows: a powder feeding device sends a certain amount of powder to the workbench surface, a powder spreading roller evenly spreads a layer of powder material on the upper surface of the formed part in the forming cylinder, a heating device heats the powder to a set temperature, and a galvanometer system controls the laser to scan the solid part of the powder layer according to the cross-sectional contour of this layer, causing the powder to melt and bond with the previously formed part below; when one cross-section is sintered, the workbench descends by the thickness of one layer, and the powder spreading roller spreads another layer of uniform and dense powder on it, and a new cross-section is scanned and sintered. After several layers of scanning and superposition, the entire prototype manufacturing is completed.
[0003] With the increasing application of additive manufacturing technology in the field of material development, more and more universities and research institutes adopt the method of mixing powders for alloy design: using laser powder bed fusion technology to develop new materials, exploring the evolution process and mechanism of the microstructure of materials, and studying methods for improving material properties. Considering that the mixed powder often cannot be recycled after printing, most units tend to use small-format machines due to powder utilization rate and cost considerations. At the same time, in the powder preparation stage, a metal powder mixing device that can achieve a small amount of powder (powder mixing mass < 3.0 kg) is required.
[0004] Existing metal powder mixing equipment is either for large-batch powder mixing (powder mixing mass > 3.0 kg), such as V-type mixers and double-cone mixers. It is not suitable for small-amount powder mixing; or the mixer is equipped with an internal stirring mechanism, which can improve the mixing efficiency, but the stirring mechanism may have an adverse effect on the spherical morphology of the powder, thereby affecting the printing effect; or the mixing motion mode is single and the mixing efficiency is low. For example, a drum-type mixer can only mix through a single circular motion. Summary of the Utility Model
[0005] To solve the above technical problems existing in the prior art, the present utility model provides a mixing device for a small amount of metal powder used in selective laser melting. Based on the centrifugal off-axis principle, this mixing device can achieve three-dimensional efficient mixing of a small amount of metal powder (powder mixing mass < 3.0 kg). When scientific research institutions and new material development enterprises use the laser powder bed melting technology to develop new materials, it not only improves the powder utilization rate and powder mixing efficiency, shortens the new material development cycle, but also reduces the R & D cost.
[0006] To solve the above technical problems, the present utility model provides a mixing device for a small amount of metal powder used in selective laser melting, comprising:
[0007] A powder mixing bottle for containing metal powder, which comprises a bottle body and a sealing cap;
[0008] A piston mechanism disposed inside the powder mixing bottle for adjusting the working volume of the powder mixing bottle according to the amount of metal powder inside the powder mixing bottle;
[0009] A first clamping mechanism and a second clamping mechanism, which respectively clamp both ends of the powder mixing bottle;
[0010] A first driving mechanism and a second driving mechanism, which are respectively fixedly connected to the first clamping mechanism and the second clamping mechanism. The straight line connecting the center of the bottom surface of the rotating shaft of the first driving mechanism and the center of the bottom surface of the rotating shaft of the second driving mechanism neither coincides nor is parallel to the straight line connecting the centers of the upper and lower bottom surfaces of the powder mixing bottle in space; so as to drive the first clamping mechanism and the second clamping mechanism to move respectively by driving the first driving mechanism and the second driving mechanism, so as to mix the metal powder inside the powder mixing bottle.
[0011] As a further preferred solution of the present utility model, the first driving mechanism is a main driving stepper motor, and the second driving mechanism is an auxiliary driving stepper motor.
[0012] As a further preferred solution of the present utility model, the first clamping mechanism is used to clamp the head of the powder mixing bottle close to the sealing cap; the second clamping mechanism is used to clamp the bottom of the powder mixing bottle away from the sealing cap.
[0013] As a further preferred solution of the present utility model, the coordinated driving of the main driving stepper motor and the auxiliary driving stepper motor realizes the reverse rotation of the powder mixing bottle, or the alternating rotation of the forward and reverse directions.
[0014] As a further preferred solution of the present utility model, the mixing device further comprises a first bracket and a second bracket. The main driving stepper motor is installed on the first bracket; the auxiliary driving stepper motor is installed on the second bracket.
[0015] As a further preferred solution of the present utility model, the powder mixing bottle is cylindrical and semi-transparent.
[0016] As a further preferred embodiment of the present utility model, the outer wall of the powder mixing bottle is provided with volume equal division scales, and there are several micro-convex points on the inner wall.
[0017] As a further preferred embodiment of the present utility model, the volume of the metal powder in the powder mixing bottle accounts for 2 / 5 to 3 / 5 of the working volume.
[0018] As a further preferred embodiment of the present utility model, the piston mechanism includes a piston rod and a piston head. One end of the piston rod is fixed to the sealing cover, and the other end is connected to the piston head. Moreover, the piston rod can perform telescopic movement, and the piston head and the bottom of the bottle body form a sealed working volume.
[0019] As a further preferred embodiment of the present utility model, the piston rod is fixed to the sealing cover through a first fastening nut.
[0020] The mixing device for a small amount of metal powder for selective laser melting of the present utility model includes: a powder mixing bottle for containing metal powder, which includes a bottle body and a sealing cover; a piston mechanism arranged in the powder mixing bottle for adjusting the working volume of the powder mixing bottle according to the amount of metal powder in the powder mixing bottle; a first clamping mechanism and a second clamping mechanism, which respectively clamp both ends of the powder mixing bottle; a first driving mechanism and a second driving mechanism, which are respectively fixedly connected to the first clamping mechanism and the second clamping mechanism. The straight line connecting the center of the bottom surface of the rotating shaft of the first driving mechanism and the center of the bottom surface of the rotating shaft of the second driving mechanism neither coincides nor is parallel to the straight line connecting the centers of the upper and lower bottom surfaces of the powder mixing bottle in space; so as to drive the first driving mechanism and the second driving mechanism to drive the first clamping mechanism and the second clamping mechanism to move respectively, so as to mix the metal powder in the powder mixing bottle, so that based on the principle of centrifugal off-axis, three-dimensional efficient mixing of a small amount of metal powder (powder mixing quality < 3.0 kg) can be realized. For research institutes and new material development enterprises using the laser powder bed melting technology to develop new materials, it not only improves the powder utilization rate and powder mixing efficiency, shortens the new material development cycle, but also reduces the R & D cost. Description of the Drawings
[0021] Figure 1 The working state of an embodiment provided for the mixing device for a small amount of metal powder for selective laser melting of the present utility model Figure 1 ;
[0022] Figure 2 The working state of an embodiment provided for the mixing device for a small amount of metal powder for selective laser melting of the present utility model Figure 2 ;
[0023] Figure 3 The structural schematic diagram of the powder mixing bottle in the present utility model;
[0024] Figure 4 This is a schematic diagram of the inner wall structure of the bottle body in the present utility model.
[0025] The component markings in the figure are as follows:
[0026] 1. Main driving stepper motor, 2. First bracket, 3. First clamping mechanism, 4. Powder mixing bottle, 5. Second clamping mechanism, 6. Second bracket, 7. Auxiliary driving stepper motor, 4.1. Piston rod, 4.2. Piston head, 4.3. Bottle body, 4.4. Sealing cover, 4.5. First fastening nut, 4.6. Second fastening nut, 8. Micro bumps. Specific embodiments
[0027] In order to enable those skilled in the art to better understand and implement the technical solution of the present utility model, the following will further elaborate in detail with reference to the accompanying drawings of the specification and specific embodiments.
[0028] To solve the above technical problems, the present utility model provides a mixing device for a small amount of metal powder for selective laser melting, as Figure 1 and Figure 2 shown, which includes:
[0029] A powder mixing bottle 4 for containing metal powder, which includes a bottle body 4.3 and a sealing cover 4.4;
[0030] A piston mechanism disposed in the powder mixing bottle 4 for adjusting the working volume of the powder mixing bottle 4 according to the amount of metal powder in the powder mixing bottle 4;
[0031] A first clamping mechanism 3 and a second clamping mechanism 5, which respectively clamp both ends of the powder mixing bottle 4;
[0032] A first driving mechanism and a second driving mechanism, which are respectively fixedly connected to the first clamping mechanism 3 and the second clamping mechanism 5, and the straight line connecting the center of the bottom surface of the rotating shaft of the first driving mechanism and the center of the bottom surface of the rotating shaft of the second driving mechanism neither coincides nor is parallel to the straight line connecting the centers of the upper and lower bottom surfaces of the powder mixing bottle 4 in space; so as to drive the first clamping mechanism 3 and the second clamping mechanism 5 to move respectively by driving the first driving mechanism and the second driving mechanism, so as to mix the metal powder in the powder mixing bottle 4.
[0033] In specific implementation, the first driving mechanism is the main driving stepper motor 1, and the second driving mechanism is the auxiliary driving stepper motor 7. The first clamping mechanism 3 is used to clamp the head of the powder mixing bottle 4 near the sealing cap 4.4; the second clamping mechanism 5 is used to clamp the bottom of the powder mixing bottle 4 away from the sealing cap 4.4. The coordinated driving of the main driving stepper motor 1 and the auxiliary driving stepper motor 7 realizes the reverse rotation of the powder mixing bottle 4, or the alternating rotation in both forward and reverse directions. Specifically, the powder mixing device can complete the setting of two completion modes through the motor: a. Manually confirm and stop mixing; b. Set the powder mixing time, and when the time counting is completed, it is considered that the powder mixing is completed and the powder mixing is stopped.
[0034] Specifically, the mixing device further includes a first bracket 2 and a second bracket 6. The main driving stepper motor 1 is installed on the first bracket 2; the auxiliary driving stepper motor 7 is installed on the second bracket 6.
[0035] Preferably, as Figure 3 shown, the powder mixing bottle 4 is cylindrical and translucent. The outer wall of the powder mixing bottle 4 is provided with volume equal division scales. One end of the piston rod 4.1 is fixed to the sealing cap 4.4, and the other end is connected to the piston head 4.2. And the piston rod 4.1 can perform telescopic movement. The piston head 4.2 and the bottom of the bottle body 4.3 form a sealed working volume. Specifically, both ends of the piston rod 4.1 are provided with threads. One end of the piston rod 4.1 is fixed to the sealing cap 4.4 through a first fastening nut 4.5, and the other end of the piston rod 4.1 is fixed to the piston head 4.2 through a second fastening nut 4.6. In this way, after the pre-weighed powders are filled into the bottle body 4.3, the ratio relationship between the powder amount and the volume of the bottle body 4.3 can be calculated through the external scale of the powder mixing bottle 4, so as to adjust the length of the telescopic piston rod 4.1 and lock it. Further preferably, as Figure 4 shown, there are several micro-convex points 8 on the inner wall of the bottle body 4.3, which can further improve the powder mixing effect.
[0036] Preferably, the volume of the metal powder in the powder mixing bottle 4 accounts for 2 / 5 - 3 / 5 of the working volume, and this ratio has a better powder mixing effect. Because too much or too little powder is not easy to be fully mixed. The piston head 4.2 and the bottom of the bottle body 4.3 form a sealed working volume, and this working volume is the powder mixing area.
[0037] In order to enable those skilled in the art to better understand and implement the technical solution of the present utility model, the working process of the mixing device for a small amount of metal powder for selective laser melting of the present utility model will be specifically described below in the form of embodiments.
[0038] Example 1 TC4 + 2.0WT.% 316L
[0039] The total mass of the mixed powders of TC4 and 316L is 2.2 kg, and 316L accounts for 2 WT.% (WT.% means mass fraction). Weigh 2156 g of TC4 powder and 44 g of 316L powder respectively, and put the powders into the powder mixing bottle 4. Through the external scale of the powder mixing bottle 4, confirm that the powder is close to the scale position, adjust the length of the telescopic piston rod 4.1 so that the piston head 4.2 is at the scale 5 position, and lock it in place. Fix the piston rod 4.1 and the piston head 4.2 with bolts and nuts. Fix the piston rod 4.1 and the sealing cover 4.4 with the first fastening nut 4.5 to make the powder volume account for 2 / 5 - 3 / 5 of the powder mixing area of the powder mixing bottle 4. The powder mixing area refers to the working space enclosed by the piston head 4.2 and the bottle body 4.3.
[0040] Fix the powder mixing bottle 4 with the first clamping mechanism 3 and the second clamping mechanism 5. The second clamping mechanism 5 clamps the bottom of the powder mixing bottle 4, that is, the part away from the sealing cover 4.4. The first clamping mechanism 3 clamps the head of the powder mixing bottle 4, that is, the part close to the sealing cover 4.4. Fix the main driving stepper motor 1 and the first clamping mechanism 3 with bolts. Fix the second clamping mechanism 5 and the auxiliary driving stepper motor 7 with bolts.
[0041] Adjust the main driving stepper motor 1 to make the rotation frequency of the powder mixing bottle 4 be 50 r / min, and set the powder mixing time to 2.5 h. After powder mixing for 2.5 h, the powder mixing device stops working and the powder mixing is completed. The material printed with the mixed powder after mixing is corroded with Kelly's etching solution. The optical microscope photos confirm that the powder mixing effect is good.
[0042] Example 2 SAF2205 + 6.0 WT.% Ni
[0043] The mixed powder mass of SAF2205 and pure nickel powder is 1.2 kg, and the pure Ni powder accounts for 6 WT.%. Weigh 1128 g of SAF2205 powder and 72 g of pure nickel powder respectively, and put the powders into the powder mixing bottle 4. Through the external scale of the powder mixing bottle 4, confirm that the powder volume is between the scales 1 and 2, adjust the length of the telescopic piston rod 4.1 so that the piston head 4.2 is at the scale 3 position, and lock it in place. Fix the piston rod 4.1 and the piston head 4.2 with bolts and nuts. Fix the piston rod 4.1 and the sealing cover 4.4 with the first fastening nut 4.5 to make the powder volume account for 2 / 5 - 3 / 5 of the powder mixing area of the powder mixing bottle 4. The powder mixing area refers to the space enclosed by the piston head 4.2 and the bottle body 4.3.
[0044] Fix the powder mixing bottle 4 with the first clamping mechanism 3 and the second clamping mechanism 5. The second clamping mechanism 5 clamps the bottom of the powder mixing bottle 4, that is, the part away from the sealing cap 4.4. The first clamping mechanism 3 clamps the head of the powder mixing bottle 4, that is, the part close to the sealing cap 4.4. Fix the main drive stepping motor 1 and the first clamping mechanism 3 with bolts; fix the second clamping mechanism 5 and the auxiliary drive stepping motor 7 with bolts.
[0045] By adjusting the main drive stepping motor 1 and the auxiliary drive stepping motor 7, the powder mixing bottle 4 is rotated forward and backward. The forward rotation frequency is 60 r / min, the reverse rotation frequency is 30 r / min, and the powder mixing time is set to 48 hours. After 48 hours of powder mixing, the powder mixing device stops working and the powder mixing is completed. For the material printed with this mixed powder, the distribution of austenite phase in the matrix is observed by means of electrochemical corrosion. It is confirmed that the powder mixing effect is good through the optical microscope photos.
[0046] The above embodiments are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention shall belong to the protection scope of the present invention. It should be noted that several modifications and decorations made without departing from the principle of the present invention shall be regarded as within the protection scope of the present invention.
Claims
1. A mixing device for a small amount of metal powder for laser selective melting, characterized in that: include: A powder mixing bottle, used for containing metal powder, comprising a bottle body and a sealing cover; A piston mechanism is disposed in the powder mixing bottle and is used to adjust the working volume of the powder mixing bottle according to the amount of metal powder in the powder mixing bottle; A first clamping mechanism and a second clamping mechanism, which clamp two ends of the powder mixing bottle respectively; The first driving mechanism and the second driving mechanism are fixedly connected to the first clamping mechanism and the second clamping mechanism respectively, and the straight line formed by the bottom center of the rotating shaft of the first driving mechanism and the bottom center of the rotating shaft of the second driving mechanism and the line connecting the upper and lower bottom centers of the powder mixing bottle are neither coincident nor parallel in space; the first driving mechanism and the second driving mechanism are driven to move the first clamping mechanism and the second clamping mechanism respectively to mix the metal powder in the powder mixing bottle.
2. The mixing device for a small amount of metal powder for laser selective melting according to claim 1, characterized in that: The first driving mechanism is a main driving stepping motor, and the second driving mechanism is an auxiliary driving stepping motor.
3. The mixing device for a small amount of metal powder for laser selective melting according to claim 2, characterized in that: The first clamping mechanism is used to clamp the head of the powder mixing bottle close to the sealing cover; the second clamping mechanism is used to clamp the bottom of the powder mixing bottle away from the sealing cover.
4. The mixing device for a small amount of metal powder for laser selective melting according to claim 3, characterized in that: The main driving stepping motor and the auxiliary driving stepping motor are driven in coordination to realize the reverse rotation of the powder mixing bottle, or the alternating forward and reverse rotation.
5. The mixing device for a small amount of metal powder for laser selective melting according to claim 4, characterized in that: The mixing device further comprises a first bracket and a second bracket, wherein the main driving stepping motor is mounted on the first bracket; and the auxiliary driving stepping motor is mounted on the second bracket.
6. The mixing device for a small amount of metal powder for laser selective melting according to claim 1, characterized in that: The powder mixing bottle is cylindrical and translucent.
7. The mixing device for a small amount of metal powder for laser selective melting according to claim 1, characterized in that: The outer wall of the powder mixing bottle is provided with volume equal division scales, and the inner wall is provided with a plurality of micro convex points.
8. The mixing device for a small amount of metal powder for laser selective melting according to claim 1, characterized in that: The volume of the metal powder in the powder mixing bottle accounts for 2 / 5 to 3 / 5 of the working volume.
9. The mixing device for a small amount of metal powder for laser selective melting according to any one of claims 1 to 8, characterized in that: The piston mechanism comprises a piston rod and a piston head, one end of the piston rod is fixed on the sealing cover, and the other end is connected to the piston head, and the piston rod can perform telescopic movement, and the piston head and the bottom of the bottle body form a closed working volume.
10. The mixing device for a small amount of metal powder for laser selective melting according to claim 9, characterized in that: The piston rod is fixed on the sealing cover through a first fastening nut.