Regenerated powder mixing method for 3D printing

Abstract

The invention discloses a regenerated powder mixing method for 3D (three-dimensional) printing, which is characterized in that new and old powder repeatedly falls onto a horizontally rotating blade from top to bottom, and the new and old powder is scattered downwards by means of rotation of the blade to realize primary mixing. According to the 3D printing powder recycling device, new and old powder mixing operation during 3D printing powder recycling can be better achieved, and the powder recycling effect is better improved.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D powder printing, and particularly to a method for mixing recycled powder for 3D printing. Background Art

[0002] Additive manufacturing, also known as 3D printing, works by stacking materials layer by layer to form an object. 3D printing technology has prominent advantages, can support personalized customization, and has an increasing market demand. The materials used in 3D printing are usually powder materials. Since 3D printing only cures the powder required in the printing range, a large amount of residual powder will be generated in the remaining positions after printing.

[0003] The powder materials for 3D printing, especially for metal powder materials, have a relatively high cost themselves, and it is necessary to consider recycling the printing residual powder. Directly using the residual old powder after 3D printing for secondary printing will cause a serious decline in printing quality. Therefore, a certain proportion of new powder is usually added and mixed for recycling, which can better ensure the printing quality of the recycled powder.

[0004] CN210023767U once disclosed a device for recycling and reusing metal 3D printing powder. In this patent, a method of realizing regeneration by mixing new and old powder materials is adopted. However, the device for realizing powder mixing is relatively conventional, and the powder mixing efficiency is poor.

[0005] Therefore, how to design a method for mixing recycled powder that can more efficiently and quickly mix new and old powder and improve the quality of powder regeneration has become a problem to be considered by those skilled in the art. Summary of the Invention

[0006] Aiming at the deficiencies of the above-mentioned prior art, the technical problem to be solved by the present invention is: how to provide a method for mixing recycled powder for 3D printing that can efficiently and quickly mix new and old powder and improve the quality of powder regeneration.

[0007] To solve the above technical problem, the present invention adopts the following technical solution: A method for mixing recycled powder for 3D printing, characterized in that the new and old powder is repeatedly dropped from above onto horizontally rotating blades, and the new and old powder is scattered downward by the rotation of the blades to achieve preliminary mixing.

[0008] In this way, the powder is dropped from above onto the high-speed rotating blades, and it is dynamically dispersed and mixed by the blades in the air. Repeating this process can greatly improve the mixing effect and efficiency of the powder material. At the same time, during the process of the high-speed rotating blades dispersing the powder, some powder clusters that are fixed due to being contaminated by the printing material in the old powder can also be dispersed into particles, better improving the quality of the recycled powder and ensuring the forming effect of subsequent reuse.

[0009] Furthermore, the preliminarily mixed powder is collected in a basin-shaped container, and the basin-shaped container is controlled to vibrate up and down and sway left and right while rotating horizontally to achieve further mixing of the powder material.

[0010] In this way, under the multiple combined actions of rotation and swaying, the mixing effect of the powder material is better improved.

[0011] Furthermore, this method is realized by relying on a 3D printing powder mixing device. The 3D printing powder mixing device includes a vertically cylindrical shell. At the upper end of the shell, a recycled powder interface and a newly added powder interface are respectively opened upward. In the upper part of the inner cavity of the shell, a sprinkling and mixing device is also provided, and in the lower part of the shell, a jolting and mixing device and a discharging device are also provided.

[0012] In this way, the recycled powder enters from the recycled powder inlet, and the newly added powder enters from the newly added powder inlet. The two kinds of powder materials are mixed in the inner cavity of the shell through two different principle mixing methods of the sprinkling and mixing device and the jolting and mixing device in sequence, and then discharged after being better mixed evenly, which better improves the mixing efficiency and mixing quality.

[0013] Furthermore, an electric heating module interlayer is also provided in the shell. In this way, by using the electric heating method to heat the powder material inside, drying can be quickly achieved, avoiding the influence of moisture in the powder material on subsequent use.

[0014] Furthermore, a protective gas device is also installed on the shell. The protective gas device includes an air extraction joint and an air inlet joint exposed in the inner cavity wall of the shell. The air extraction joint is externally connected to an air extraction pipeline and is used to connect to an air extraction fan, and the air inlet joint is externally connected to an air inlet pipeline and is used to connect to a protective gas cylinder. Control valves are also installed on the air extraction pipeline and the air inlet pipeline.

[0015] In this way, the control valve is connected to the control center. When some powder materials need to isolate air during the heating and drying process, the air extraction joint can be controlled to extract air from the inner cavity of the shell, and then the air inlet joint can be controlled to introduce protective gas to isolate the internal air to form an atmosphere protection, avoiding oxidation and denaturation of the powder material during heating. During implementation, an oxygen sensing probe can be further installed on the inner wall of the shell and connected to the control center to better achieve control.

[0016] Furthermore, a feed channel is upwardly connected to each of the recycled powder interface and the newly added powder interface, and a feed control switch is provided at the lower end of the feed channel. This facilitates the control of the feed.

[0017] Furthermore, the feed control switch includes a feed switch baffle which is horizontally arranged on the insertion interface on one side of the feed channel in a pull-out manner. The outer end of the feed switch baffle can be inserted and pulled out of the insertion interface and is connected to an electric push rod device for feed control located at the upper end of the housing. A weighing sensor is also provided on the feed switch baffle.

[0018] In this way, after the powder enters the feed channel, it can be weighed by the weighing sensor. After meeting the requirements, the electric push rod device is controlled to pull the feed switch baffle so that the powder falls into the inner cavity of the housing, which facilitates the control of the feed ratio of the recycled powder and the newly added powder. During implementation, the output end of the weighing sensor is connected to the input end of the weight transmitter (or directly connected to the control center), and the output end of the weight transmitter is connected to the input end of the electric push rod. Parameters can be set for the weight transmitter. The output signal of the weighing sensor will be compared with the set value in the weight transmitter. When the weight reaches the set weight, the weight transmitter will input a corresponding control signal to the electric push rod to make the electric push rod work.

[0019] Furthermore, a dust-proof cover is also provided at the upper end of the housing. The upper end of the feed channel at the upper end of the recycled powder interface passes through the dust-proof cover and is used to dock with the screening box outlet of the 3D printing powder crushing and screening device. The upper end of the feed channel above the newly added powder interface passes through the dust-proof cover and is provided with an outwardly folded section, and a switch cover is provided at the upper end of the folded section.

[0020] In this way, it is convenient to achieve dust prevention for the feed and ensure environmental hygiene.

[0021] Furthermore, the sprinkling and mixing device includes a sprinkling and mixing rotating shaft vertically installed in the middle of the upper end of the inner cavity of the housing. The upper end of the sprinkling and mixing rotating shaft can rotatably pass through the housing and is connected to a sprinkling and mixing motor installed at the upper end of the housing. A plurality of first mixing blades are uniformly arranged along the circumference at the upper part of the sprinkling and mixing rotating shaft. The projections of the recycled powder interface and the newly added powder interface downward fall within the rotation range of the first mixing blades. A blanking funnel is arranged outside the first mixing blades. The upper end of the blanking funnel is fixed at the upper end of the inner cavity of the housing and the lower end outlet is suspended. The lower end position of the sprinkling and mixing rotating shaft extends downward beyond the lower end outlet of the blanking funnel, and a plurality of second mixing blades are uniformly installed along the circumference at the lower end of the sprinkling and mixing rotating shaft. The projection of the lower end outlet of the blanking funnel downward falls within the rotation range of the second mixing blades.

[0022] In this way, when the device is in use, the sprinkling and mixing motor drives the first mixing blade and the second mixing blade to rotate at high speed. After the old and new powder materials enter the inner cavity of the housing from the recycled powder material interface and the newly added powder material interface respectively, they fall onto the first mixing blade, and are scattered around by the first mixing blade rotating at high speed and mixed onto the blanking funnel. After converging downward through the blanking funnel, they fall onto the second mixing blade again, and are scattered around by the second mixing blade rotating at high speed again and fall into the lower part of the inner cavity of the housing. Compared with the conventional mixing method that is prone to mixing dead angles during stirring, in this device, during the dynamic process of the powder material falling in the air, after being repeatedly scattered, mixed and dropped by the two blades twice, an efficient and fast dynamic mixing process is realized, and a good mixing effect is achieved. In addition, during the process of the sprinkling and mixing device scattering the powder material by the rotating blades, it can scatter the stringy powder particles that are difficult to remove by screening due to adhesion by the solidifying material in one direction, break their adhesion, and better improve the regeneration quality of the powder material to ensure the forming effect during repeated use.

[0023] Further, two columns of guide protrusions are symmetrically arranged on the left and right on the inner side surface of the blanking funnel. The upper ends of the guide protrusions are located at the middle positions on the left and right sides of the inner side surface of the blanking funnel, and the lower ends extend spirally to the lower edge of the other side of the inner side surface of the blanking funnel.

[0024] This is because when the old and new powder materials enter the inner cavity of the housing from the recycled powder material interface and the newly added powder material interface respectively and are scattered onto the blanking funnel by the first mixing blade, there is still a large directionality, that is, the old and new powder materials will relatively concentrate and fall onto one side respectively. Therefore, after setting the above-mentioned guide protrusions, a part (about half) of the powder material scattered and dropped onto one side of the funnel can be guided by the guide protrusions to fall onto the other side of the funnel. Then, after being scattered again by the second mixing blade, the uniformity of chaos is greatly improved.

[0025] Further, the height of the guide protrusion is gradually increased from top to bottom. In this way, the above-mentioned powder material guiding effect can be better ensured.

[0026] Furthermore, the tipping and mixing device includes a mixing basin located at the lower end of the inner cavity of the housing. The mixing basin has an upward opening and a circular shape that matches the inner cavity wall of the housing. The middle of the lower end of the mixing basin is supported and installed at the upper end of a vertically arranged tipping and mixing rotating shaft through a universal joint. The lower end of the tipping and mixing rotating shaft is connected to a tipping and mixing motor installed on the base. A vibration motor is also installed on the mixing basin, and the vibration motor is used to output vertical vibration to the mixing basin. Multiple support rods are also downwardly arranged at the peripheral position of the lower surface of the mixing basin. The support rods are evenly distributed in a ring with the tipping and mixing rotating shaft as the axis. The support rods have an upper half section and a lower half section that are inserted and matched with each other to form a sleeve structure. A vertical support spring is arranged inside the upper half section and the lower half section to form a vertical elastic support connection. The upper end of the upper half section is rotatably installed on the lower surface of the mixing basin through a hinge joint. The hinge axis direction of the hinge joint is arranged along the direction perpendicular to the diameter of the mixing basin. The lower end of the lower half section is rotatably supported and installed in a circular track groove on the upper surface of a base through a roller. At least one arc-shaped protrusion or depression is arranged on the bottom surface of the track groove.

[0027] In this way, after the powder falls into the mixing basin, the mixing basin is driven by the tipping and mixing motor to rotate at a high speed. At the same time, the vibration motor drives the mixing basin to vibrate up and down to vibrate the material upward and then throw it up. Then, while the mixing basin is rotating, each support rod below moves in the track groove. When the support rod encounters an arc-shaped protrusion or depression, the side of the mixing basin is lifted or lowered, thereby generating a yaw and producing a "similar" mixing effect of tipping the material in the mixing basin. Therefore, the structure of the tipping and mixing device enables the material in the mixing basin to be simultaneously subjected to the combined action of several effects, producing a tipping and mixing effect similar to that of a wok. This multi-force cooperation method can make the movement path of the powder in the powder mixing platform more complex and diverse. Compared with the conventional vibration mixing method, the powder is more fully interpenetrated and mixed with each other, thereby achieving a higher powder mixing uniformity. For example, when mixing some powders with large particle size differences or easy to agglomerate, the new invention can better break the agglomerates and make the large and small particles evenly distributed. Therefore, it can greatly improve the uniformity and effectiveness of powder mixing.

[0028] Furthermore, multiple vibration motors are annularly and evenly arranged and installed around the lower surface of the mixing basin. In this way, each vibration motor is connected to the control center. The control center can control each vibration motor to vibrate simultaneously through the internal program to provide an upward vibration effect for the mixing tray at the same time, or can control each vibration motor to vibrate sequentially in a single cycle to provide an upward vibration effect for one side of the mixing tray sequentially in a cycle. Therefore, it can better provide sufficient up and down vibration mode selection for the mixing of the mixing basin. Coupled with the combined movement of yaw and rotation, a better mixing effect is produced.

[0029] Furthermore, a connecting column made of elastic material is fixed downwardly provided in the middle of the lower end of the mixing bowl, and the universal joint is installed at the lower end of the connecting column and connected downwardly to the mixing shaft. In this way, the connecting column provides sufficient elasticity so that the mixing bowl can better achieve up and down vibration and left and right deflection, avoiding the restriction of vibration and deflection caused by rigid connection.

[0030] Furthermore, an elastic edge ring made of elastic material is extended upward and outward from the upper edge of the mixing bowl, and the upper edge of the elastic edge ring fits the inner cavity of the shell. This better ensures that the upper powder can fall into the mixing bowl better and will not fall out from the edge gap, and can also ensure that the mixing bowl has enough space and room to directly swing and shake the material in the inner cavity of the shell, so as to avoid the powder dust from overflowing and affecting environmental hygiene. In implementation, the elastic edge ring can be made of rubber material.

[0031] Furthermore, the shell is fixed on a support frame, the base is installed and fixed on a horizontally arranged lifting plate, the end of the lifting plate can be slidably engaged with the lifting guide rail vertically arranged on the support frame, and a lifting control mechanism is also provided on the support frame and connected to the lifting plate.

[0032] In this way, the lifting control mechanism can control the lifting movement of the lifting plate, and after the lifting plate rises, the mixing bowl is in the inner cavity of the shell and receives and mixes the materials. When the powder materials are mixed in the mixing bowl, the lifting plate can be controlled to descend, so that the mixing bowl is exposed downward from the shell, which is convenient for discharging.

[0033] Furthermore, the lifting control mechanism includes a vertically arranged synchronous belt mechanism, the synchronous belt mechanism includes a pair of vertically arranged synchronous belt pulleys and a synchronous belt wound on the synchronous belt pulleys, the synchronous belt pulleys are drivingly connected to a lifting motor, and the synchronous belt is fixedly connected to the lifting plate. This has the characteristics of simple structure and stable and reliable lifting control.

[0034] Furthermore, a detachable material holding basin is fitted in the mixing basin, a clamping strip is protruding outwardly from the outer surface of the material holding basin, and a clamping slot is correspondingly provided on the inner surface of the mixing basin for the clamping strip to be inserted and matched.

[0035] In this way, it is convenient to directly take out the material holding basin when discharging the material and obtain the recycled powder for reuse.

[0036] In summary, the present invention can better realize the mixing operation of new and old powders during 3D printing powder recycling, and better improve the recycling effect of powders. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1This is a schematic structural view of the 3D printing powder mixing device used in the embodiment of the present invention after removing the support frame and the lifting control mechanism. In the figure, some components are in a disassembled and separated state to better show the structure of the remaining parts.

[0038] Figure 2 It is Figure 1 a schematic three-dimensional structural view of the remaining components in the upper and lower split and half-sectioned state after removing the protective gas device.

[0039] Figure 3 It is Figure 2 a schematic three-dimensional structural view of the components of the separate material tumbling and mixing device after being split up and down.

[0040] Figure 4 It is Figure 1 a schematic structural view of the separate protective gas device.

[0041] Figure 5 This is a schematic structural view of the separate support frame and lifting control mechanism of the 3D printing powder mixing device used in the embodiment of the present invention.

[0042] Figure 6 This is a schematic overall structural view of the 3D printing powder mixing device used in the embodiment of the present invention. Specific Embodiments

[0043] The following further elaborates on the present invention in conjunction with specific embodiments.

[0044] Specific Embodiment: A method for mixing recycled powder for 3D printing, characterized in that the new and old powders are repeatedly dropped from above onto horizontally rotating blades, and the new and old powders are dispersed downward by the rotation of the blades to achieve preliminary mixing.

[0045] In this way, the powder is dropped from above onto the high-speed rotating blades, and it is dynamically dispersed and mixed by the blades in the air. Repeating this process can greatly improve the mixing effect and efficiency of the powder material. At the same time, during the process of the high-speed rotation of the blades to disperse the powder, some powder clusters that are solidified due to being contaminated by the printing material in the old powder can also be dispersed into particles, better improving the quality of the recycled powder and ensuring the forming effect of subsequent reuse.

[0046] During implementation, the preliminarily mixed powder is collected in a basin-shaped container, and the basin-shaped container is controlled to rotate horizontally while vibrating up and down and swaying left and right to achieve further mixing of the powder material.

[0047] In this way, under the multiple combined actions of rotation and oscillation, the mixing effect of the powder material can be better improved.

[0048] In implementation, this method relies on a 3D printing powder mixing device. For the 3D printing powder mixing device, refer to Figures 1-6 , which includes a vertically cylindrical housing 30. At the upper end of the housing 30, a recycled powder interface 31 and a newly added powder interface 32 are respectively opened upward. An upper part of the inner cavity of the housing is also provided with a sprinkling mixing device, and a lower part of the housing is also provided with a jolting mixing device and a discharging device.

[0049] In this way, the recycled powder enters from the recycled powder inlet, and the newly added powder enters from the newly added powder inlet. The two kinds of powders are mixed in the inner cavity of the housing through two different mixing methods of the sprinkling mixing device and the jolting mixing device in sequence, so as to be better mixed evenly and then discharged, which better improves the mixing efficiency and mixing quality.

[0050] Among them, an electric heating module interlayer 33 is also provided in the housing 30. In this way, by using the electric heating method to heat the internal powder, drying can be quickly realized, and the influence of moisture in the powder on subsequent use can be avoided.

[0051] Among them, a protective gas device 34 is also installed on the housing. The protective gas device 34 includes an air extraction joint 35 and an air inlet joint 36 exposed in the inner cavity wall of the housing. The air extraction joint is externally connected to an air extraction pipeline and is used to connect to an air extraction fan, and the air inlet joint is externally connected to an air inlet pipeline and is used to connect to a protective gas cylinder. Control valves 37 are also installed on the air extraction pipeline and the air inlet pipeline.

[0052] In this way, the control valve is connected to the control center. When some powders need to be isolated from air during the heating and drying process, the air extraction joint can be controlled to extract air from the inner cavity of the housing, and then the air inlet joint can be controlled to introduce protective gas to isolate the internal air to form an atmosphere protection, so as to avoid oxidation and denaturation of the powder during heating. During implementation, an oxygen sensing probe can be further installed on the inner wall of the housing and connected to the control center to better achieve control.

[0053] Among them, feeding channels are respectively connected upward on the recycled powder interface 31 and the newly added powder interface 32, and a feeding control switch is arranged at the lower end position of the feeding channels. This facilitates the control of feeding.

[0054] Among them, the feeding control switch includes a feeding switch baffle 40. The feeding switch baffle 40 is horizontally arranged in an insertion opening on one side of the feeding channel in a pullable manner. The outer end of the feeding switch baffle penetrates the insertion opening in a pluggable manner and is connected to an electric push rod device 41 for feeding control located at the upper end of the housing. A weighing sensor 42 is also arranged on the feeding switch baffle 40. During implementation, the electric push rod device 41 for feeding control is connected to a weight transmitter 43 located at the upper end of the housing.

[0055] After the powder material enters the feeding channel, it can be weighed by the weighing sensor. After meeting the requirements, the electric push rod device is controlled to pull the feeding switch baffle so that the powder material falls into the inner cavity of the shell, which is convenient to realize the control of the feeding ratio of the recycled powder material and the newly added powder material. During implementation, the output end of the weighing sensor is connected to the input end of the weight transmitter (or directly connected to the control center), and the output end of the weight transmitter is connected to the input end of the electric push rod. Parameters can be set for the weight transmitter. The output signal of the weighing sensor will be compared with the set value in the weight transmitter. When the weight reaches the set weight, the weight transmitter will input a corresponding control signal to the electric push rod to make the electric push rod work.

[0056] Wherein, a dust-proof cover 44 is further arranged at the upper end of the shell. The upper end of the feeding channel above the recycled powder material interface 31 passes through the dust-proof cover 44 and is used for docking with the screening box outlet of the 3D printing powder crushing and screening device. The upper end of the feeding channel above the newly added powder material interface 32 passes through the dust-proof cover and is provided with an outward folding section 45, and a switch cover 46 is arranged at the upper end of the folding section.

[0057] In this way, it is convenient to achieve dust prevention during feeding and ensure environmental sanitation.

[0058] Wherein, the sprinkling and mixing device includes a sprinkling and mixing rotating shaft 50 vertically installed in the middle of the upper end of the inner cavity of the shell. The upper end of the sprinkling and mixing rotating shaft 50 rotatably passes through the shell 30 and is connected to a sprinkling and mixing motor 51 installed at the upper end of the shell. A plurality of first mixing blades 52 are evenly arranged along the circumference at the upper part of the sprinkling and mixing rotating shaft 50. The projections of the recycled powder material interface 31 and the newly added powder material interface 32 downward fall within the rotation range of the first mixing blades 52. A material dropping funnel 53 is arranged outside the first mixing blades 52. The upper end of the material dropping funnel 53 is fixed at the upper end of the inner cavity of the shell and the lower end outlet is suspended. The lower end position of the sprinkling and mixing rotating shaft 50 extends downward beyond the lower end outlet position of the material dropping funnel, and a plurality of second mixing blades 54 are evenly installed along the circumference at the lower end of the sprinkling and mixing rotating shaft 50. The projection of the lower end outlet of the material dropping funnel downward falls within the rotation range of the second mixing blades 54.

[0059] In this way, when the device is in use, the throwing and mixing motor drives the first mixing blade and the second mixing blade to rotate at high speed. After the old and new powder materials enter the inner cavity of the housing from the recycled powder interface and the newly added powder interface respectively, they fall onto the first mixing blade and are scattered around by the first mixing blade rotating at high speed and mixed onto the blanking funnel. After converging downward through the blanking funnel, they fall onto the second mixing blade again, and are scattered around by the second mixing blade rotating at high speed again and fall into the lower part of the inner cavity of the housing. In this way, compared with the conventional mixing method that is prone to mixing dead angles, in the dynamic process of the powder material falling in the air, this device realizes an efficient and fast dynamic mixing process through two repeated scatterings and mixings by the blades and has a good mixing effect. In addition, when the throwing and mixing device scatters the powder material by the rotating blades, it can break up the stringy powder particles that are difficult to remove by screening due to adhesion by the solidifying material in one direction, break their adhesion, and better improve the regeneration quality of the powder material to ensure the forming effect during repeated use. During implementation, the first mixing blade and the second mixing blade are integrally in the shape of long thin sheets and are inclined downward to the side of the rotating direction, and the front edge of the blade is in the shape of a blade. In this way, while scattering and stirring the powder material around, it can better cut and break up the powder material mass.

[0060] Among them, two rows of guide protrusions are symmetrically arranged on the inner side surface of the blanking funnel, the upper ends of the guide protrusions are located at the middle positions on the left and right sides of the inner side surface of the blanking funnel, and the lower ends extend spirally to the lower edge of the other side of the inner side surface of the blanking funnel.

[0061] This is because when the old and new powder materials enter the inner cavity of the housing from the recycled powder interface and the newly added powder interface respectively and are scattered onto the blanking funnel by the first mixing blade, there is still a large directionality, that is, the old and new powder materials will relatively concentrate and fall onto one side. Therefore, after setting the above-mentioned guide protrusions, a part (about half) of the powder material scattered and falling onto one side of the funnel can be guided by the guide protrusions to fall onto the other side of the funnel. Then, after being scattered again by the second mixing blade, the uniformity of mixing is greatly improved.

[0062] During implementation, the height of the guide protrusion gradually increases from top to bottom. In this way, the above-mentioned powder material guiding effect can be better ensured.

[0063] Among them, the tipping and mixing device includes a mixing basin 55 located at the lower end of the inner cavity of the housing. The mixing basin 55 has an upward opening and a circular shape that matches the inner cavity wall of the housing. The middle part of the lower end of the mixing basin 55 is supported and installed at the upper end of a vertically arranged tipping and mixing rotating shaft 57 through a universal joint 56. The lower end of the tipping and mixing rotating shaft 57 is connected to a tipping and mixing motor 58 installed on the base. A vibration motor 59 is also installed on the mixing basin 55. The vibration motor 59 is used to output vertical vibration to the mixing basin. Multiple support rods 60 are also arranged downward at the peripheral position of the lower surface of the mixing basin. The support rods 60 are evenly distributed in a ring with the tipping and mixing rotating shaft as the axis. The support rods 60 have an upper half and a lower half that are inserted into each other to form a sleeve structure. The inner parts of the upper half and the lower half are provided with vertical support springs to form a vertical elastic support connection. The upper end of the upper half is rotatably installed on the lower surface of the mixing basin 55 through a hinge joint 61. The hinge axis direction of the hinge joint 61 is set along the direction perpendicular to the diameter of the mixing basin. The lower end of the lower half is rotatably supported and installed in a circular track groove 63 on the upper surface of a base 68. At least one arc-shaped protrusion 64 or depression is provided on the groove bottom surface of the track groove 63.

[0064] In this way, after the powder falls into the mixing basin, the mixing basin is driven by the tipping and mixing motor to rotate at a high speed. At the same time, the vibration motor drives the mixing basin to vibrate up and down to vibrate the material upward and then throw it up. Then, while the mixing basin is rotating, the lower support rods move in the track groove. When the support rods encounter an arc-shaped protrusion or depression, the side of the mixing basin is lifted or lowered, thereby generating a yaw, and producing a "similar" mixing effect of tipping the material in the mixing basin. Therefore, the structure of the present tipping and mixing device enables the material in the mixing basin to be simultaneously affected by several combined action effects, producing a tipping and mixing effect similar to that of a wok. This multi-force cooperation method can make the movement path of the powder in the powder mixing platform more complex and diverse. Compared with the conventional vibration mixing method, the powder is more fully interpenetrated and mixed with each other, thereby achieving a higher powder mixing uniformity. For example, when mixing some powders with large particle size differences or easy to agglomerate, the new invention can better break the agglomerates and make the large and small particles evenly distributed. Therefore, it can greatly improve the uniformity and effectiveness of powder mixing.

[0065] Among them, a plurality of vibration motors 59 are annularly and evenly arranged and installed around the lower surface of the mixing basin. In this way, each vibration motor is connected to the control center. The control center can control each vibration motor to vibrate simultaneously through the internal program to provide a simultaneous upward vibration effect for the mixing tray, or can control each vibration motor to vibrate sequentially in a single cycle to provide a unilateral upward and sequential cyclic vibration effect for the mixing tray. Therefore, it can better provide sufficient up and down vibration mode selection for the mixing of the mixing basin. Combined with the combined movement of yaw and rotation, a better mixing effect is produced.

[0066] A connecting column 65 made of elastic material is fixed downwardly at the middle of the lower end of the mixing bowl 55, and the universal joint is installed at the lower end of the connecting column 65 and connected downwardly to the mixing shaft. In this way, the connecting column provides sufficient elasticity so that the mixing bowl can better achieve up and down vibration and left and right deflection, avoiding the restriction of vibration and deflection caused by rigid connection. In implementation, the elastic material can be made of rubber material.

[0067] The upper edge of the mixing bowl (or the material holding bowl) is extended upward and outward to be provided with an elastic edge ring 66 made of elastic material, and the upper edge of the elastic edge ring 66 is fitted with the inner cavity of the shell 30. This better ensures that the powder above can fall into the mixing bowl better and will not fall out from the edge gap, and can also ensure that the mixing bowl has enough space and room to directly swing and shake the material in the inner cavity of the shell to avoid the powder dust from overflowing and affecting environmental hygiene. In practice, the elastic edge ring can be made of rubber material.

[0068] Among them, the shell 30 is fixed on a support frame 67, and the base 68 is installed and fixed on a horizontally arranged lifting plate 69. The end of the lifting plate 69 can be slid up and down and snap-fitted on a lifting guide rail 70 vertically arranged on the support frame. A lifting control mechanism is also provided on the support frame 67 and connected to the lifting plate.

[0069] In this way, the lifting control mechanism can control the lifting movement of the lifting plate, and after the lifting plate rises, the mixing bowl is in the inner cavity of the shell and receives and mixes the materials. When the powder materials are mixed in the mixing bowl, the lifting plate can be controlled to descend, so that the mixing bowl is exposed downward from the shell, which is convenient for discharging.

[0070] The lifting control mechanism includes a vertically arranged synchronous belt mechanism, which includes a pair of vertically arranged synchronous belt pulleys 72 and a synchronous belt 71 wound on the synchronous belt pulleys, the synchronous belt pulleys are transmission-connected to a lifting motor 73, and the synchronous belt is fixedly connected to the lifting plate. This has the characteristics of simple structure and stable and reliable lifting control.

[0071] A detachable material holding basin 75 is fitted in the mixing basin 55 , a clamping strip is protruding outwardly from the outer surface of the material holding basin, and a corresponding clamping groove is provided on the inner surface of the mixing basin for the clamping strip to be inserted and matched.

[0072] In this way, it is convenient to directly take out the material holding basin when discharging the material and obtain the recycled powder for reuse.

Claims

1. A recycled powder mixing method for 3D printing, characterized in that: The new and old powders are repeatedly dropped from above onto the horizontally rotating blades, and the rotation of the blades breaks up the new and old powders downwards to achieve preliminary mixing.

2. The recycled powder mixing method for 3D printing according to claim 1, characterized in that: The powders after preliminary mixing are collected and placed in a basin-shaped container, and the basin-shaped container is controlled to vibrate up and down and swing left and right while rotating horizontally to achieve further mixing of the powders.

3. The recycled powder mixing method for 3D printing according to claim 1, characterized in that: This method is implemented by a 3D printing powder mixing device, which includes a vertical cylindrical shell as a whole, with a powder recovery interface and a new powder addition interface respectively opened upward at the upper end of the shell, a throwing and mixing device is also provided at the upper part of the shell inner cavity, and a material stirring and mixing device and a discharging device are also provided at the lower part of the shell.

4. The recycled powder mixing method for 3D printing according to claim 3, characterized in that: An electric heating module interlayer is also arranged in the shell.

5. The recycled powder mixing method for 3D printing according to claim 3, characterized in that: A protective gas device is also installed on the shell, and the protective gas device includes an exhaust joint and an air inlet joint exposed in the inner wall of the shell. The exhaust joint is connected to the exhaust pipe and is used to connect to the exhaust fan. The air inlet joint is connected to the air inlet pipe and is used to connect to the protective gas bottle. Control valves are also installed on the exhaust pipe and the air inlet pipe.

6. The recycled powder mixing method for 3D printing as claimed in claim 3, characterized in that: The powder recovery interface and the new powder addition interface are each upwardly connected to a feeding channel, and a feeding control switch is provided at the lower end of the feeding channel; The feed control switch includes a feed switch baffle, which is horizontally arranged on a plug-in interface on one side of the feed channel and can be pulled out. The outer end of the feed switch baffle can be pulled out of the plug-in interface and connected to an electric push rod device for feed control located at the upper end of the shell. A weighing sensor is also arranged on the feed switch baffle.

7. The recycled powder mixing method for 3D printing as claimed in claim 6, characterized in that: A dust cover is also provided at the upper end of the shell body, and the upper end of the feed channel at the upper end of the recovered powder interface passes through the dust cover and is used to connect with the screening box outlet of the 3D printing powder crushing and screening device, and the upper end of the feed channel above the newly added powder interface passes through the dust cover and is provided with an outward folding section and a switch cover is provided at the upper end of the folding section.

8. The recycled powder mixing method for 3D printing as claimed in claim 3, characterized in that: The scattering and mixing device comprises a scattering and mixing shaft vertically installed in the middle of the upper end of the inner cavity of the shell, the upper end of the scattering and mixing shaft can rotatably pass through the shell and is connected to a scattering and mixing motor installed at the upper end of the shell, a plurality of first mixing blades are evenly arranged along the circumference at the upper position of the scattering and mixing shaft, the downward projections of the recovered powder interface and the newly added powder interface fall into the rotation range of the first mixing blade, a blanking funnel is arranged on the outer side of the first mixing blade, the upper end of the blanking funnel is fixed to the upper end of the inner cavity of the shell and the lower end outlet is suspended, the lower end position of the scattering and mixing shaft exceeds the lower end outlet position of the blanking funnel downward, and a plurality of second mixing blades are evenly arranged along the circumference at the lower end of the scattering and mixing shaft, and the downward projection of the lower end outlet of the blanking funnel falls into the rotation range of the second mixing blade.

9. The recycled powder mixing method for 3D printing as claimed in claim 8, characterized in that: Two rows of guide protrusions are symmetrically arranged on the inner side of the blanking funnel. The upper ends of the guide protrusions are located in the middle of the left and right sides of the inner side of the blanking funnel, and the lower ends extend along the spiral to the lower edge of the other side of the inner side of the blanking funnel.

10. The recycled powder mixing method for 3D printing as claimed in claim 3, characterized in that: The mixing device comprises a mixing bowl located at the lower end of the inner cavity of the shell, the mixing bowl opens upward and the periphery is a circle matching the inner cavity wall of the shell, the middle part of the lower end of the mixing bowl is supported by a universal joint and installed on the upper end of a vertically arranged mixing shaft, the lower end of the mixing shaft is connected to a mixing motor installed on the base, a vibration motor is also installed on the mixing bowl, the vibration motor is used to output vertical vibration to the mixing bowl, and a plurality of support rods are arranged downward at the peripheral position of the lower surface of the mixing bowl, and the support rods are evenly distributed in the shape of a mixing bowl. The mixing shaft is an annular shaft, and the support rod has an upper half and a lower half that are plugged into each other to form a sleeve structure. The upper half and the lower half are provided with vertical support springs to form a vertical elastic support connection. The upper end of the upper half is rotatably mounted on the lower surface of the mixing bowl through a hinge joint, and the hinge axis direction of the hinge joint is arranged perpendicular to the diameter direction of the mixing bowl. The lower end of the lower half is rotatably supported and installed in an annular track groove on the upper surface of a base through a roller, and the bottom surface of the track groove is provided with at least one arc-shaped protrusion or depression. The vibration motors are multiple and evenly arranged in a circular pattern and installed around the lower surface of the mixing bowl; A connecting column made of elastic material is fixedly arranged downwardly in the middle of the lower end of the mixing basin, and the universal joint is installed at the lower end of the connecting column and is connected downwardly to the mixing shaft; An elastic edge ring made of elastic material is provided on the upper edge of the mixing bowl, extending outward and upward, and the upper edge of the elastic edge ring fits with the inner cavity of the shell; The shell is fixed on a support frame, the base is mounted and fixed on a horizontally arranged lifting plate, the end of the lifting plate can be slidably engaged and matched on a lifting guide rail vertically arranged on the support frame, and a lifting control mechanism is also arranged on the support frame and connected to the lifting plate; The lifting control mechanism includes a vertically arranged synchronous belt mechanism, the synchronous belt mechanism includes a pair of vertically arranged synchronous belt pulleys and a synchronous belt wound around the synchronous belt pulleys, the synchronous belt pulleys are drivingly connected to a lifting motor, and the synchronous belt is fixedly connected to the lifting plate; A detachable material holding basin is fitted in the mixing basin, a clamping strip is protruding outwardly from the outer surface of the material holding basin, and a clamping slot is correspondingly provided on the inner surface of the mixing basin for the clamping strip to be inserted and matched.

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