CN114262518A - Nylon powder material for selective laser sintering and preparation method thereof - Google Patents
Nylon powder material for selective laser sintering and preparation method thereof Download PDFInfo
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Abstract
The invention provides a preparation method of a nylon powder material for selective laser sintering, which comprises the following steps: the nylon granules are subjected to a deep cooling crushing process and a grading sieving process to prepare nylon powder with the average particle size of 50-75 microns and the diameter distance of 0.6-1.5; adding high polymer powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections, namely a heating area, a heat preservation area and a cooling area, which are sequentially arranged from top to bottom, the cooling area adopts a five-section cooling process, and after the nylon powder passes through the three sections, the nylon powder with the average particle size of 50-75 mu m and the diameter distance of 0.6-1.5 is prepared; and (3) adding a flow aid into the nylon powder after the nylon powder is subjected to a grading sieving process to obtain the nylon powder for selective laser sintering. The nylon powder material prepared by the invention has the advantages of moderate average particle size, narrow particle size distribution, high sphericity, high enthalpy value and wide sintering window.
Description
Technical Field
The invention belongs to the technical field of additive manufacturing, and particularly relates to a nylon powder material for selective laser sintering and a preparation method thereof.
Background
Selective laser sintering technology is currently a commonly used rapid prototyping technology that allows the creation of a computer three-dimensional model of a target part without the use of tooling, followed by slicing of the three-dimensional model with layered software, and finally by laser sintering multiple stacks of powder to obtain a three-dimensional solid.
At present, the polymer materials mainly used for the selective laser sintering technology are thermoplastic materials, such as nylon 612, polyurethane, polyamide, polyetheretherketone and other powder materials. The main methods for preparing the powder in the market comprise a solvent precipitation method and a cryogenic grinding method, wherein the powder prepared by the solvent precipitation method has high sphericity, good fluidity, high enthalpy value and wide sintering window, but the manufacturing price is high; the powder prepared by the cryogenic grinding method is low in price, but the shape is irregular spherical, the sphericity is poor, the enthalpy value is low, and the sintering window is narrow. Poor sphericity results in a check of powder flowability, which can affect powder laydown during sintering. The powder with low enthalpy value is easy to melt unsintered powder by the melted melting body depending on self heat in the sintering process, so that the surface of a workpiece is poor, the roughness of the workpiece is high, and the workpiece is easy to warp in the sintering process of the powder with narrow sintering window. Therefore, the polymer powder prepared by cryogenic grinding has poor morphology regularity, wide particle size distribution, poor fluidity, low enthalpy value and narrow sintering window, the application of the polymer powder to the selective laser sintering technology and the application scene of the selective laser sintering technology are influenced, and most of thermoplastic powder cannot be prepared by a solvent precipitation method and is generally prepared by a deep powder grinding method.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a preparation method of nylon powder for selective laser sintering, which is used for preparing the high polymer powder for selective laser sintering with low price and wide application range and improving the sphericity, enthalpy and sintering window of nylon powder materials prepared by a cryogenic grinding method. The method comprises the steps of carrying out cryogenic grinding on a nylon material, and optimizing the cryogenically ground nylon powder material by a heat treatment tower process to finally obtain the nylon powder with moderate average particle size, narrow particle size distribution, high sphericity, high enthalpy value and wide sintering window.
The invention provides a preparation method of a nylon powder material for selective laser sintering, which comprises the following steps:
the method comprises the following steps: the nylon granules are subjected to a deep cooling crushing process and a grading sieving process to prepare nylon powder with the average particle size of 50-75 microns and the diameter distance of 0.6-1.5;
step two: adding the polymer powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections, namely a heating area, a heat preservation area and a cooling area, which are sequentially arranged from top to bottom, the cooling area adopts a five-section cooling process, and after the nylon powder passes through the three sections, the nylon powder with the average particle size of 50-75 mu m and the radial distance of 0.6-1.5 is prepared;
step three: and D, adding a flow aid into the nylon powder obtained in the step two after a grading sieving process is carried out on the nylon powder, and obtaining the nylon powder for selective laser sintering.
Further preferably, the total height of the powder in the heating area is 1m, the heating temperature is 200-300 ℃, and the powder descending speed is 0.5-1.5 m/h; the total height of the powder in the heat preservation area is 20m, the heat preservation temperature is 200-300 ℃, and the powder descending speed is 3-10 m/h.
Further preferably, the total height of the powder in the cooling area is 10m, and the powder descending speed is 3-40 m/h.
Further preferably, the five-stage cooling process adopted by the cooling area specifically comprises: the descending speed of the powder in the first stage of cooling is 15-20 m/h, and the total height of the powder is 2 m; the descending speed of the second stage of cooling powder is 12-15 m/h, and the total height of the powder is 2 m; the descending speed of the powder in the third stage of cooling is 9-12 m/h, and the total height of the powder is 2 m; the descending speed of the fourth stage of powder is 6-9 m/h, and the total height of the powder is 2 m; the descending speed of the powder in the fifth stage of cooling is 3-6 m/h, and the total height of the powder is 2 m.
Further preferably, the nylon granules are nylon 1212, nylon 12, nylon 1010, nylon 11, nylon 612, nylon 610, nylon 6 or nylon 66 granules.
Further preferably, the cryogenic grinding process comprises the following steps: adding the nylon granules into a cryogenic crusher, introducing liquid nitrogen, starting the cryogenic crusher, wherein the crushing temperature is-120 to-80 ℃, and the stirring speed is 1500 to 3000 r/min.
Further preferably, the nylon powder prepared in the first step has a bulk density of 0.38-0.45 g/cc, a enthalpy value of 30-50J/g and a sintering window of 20-30 ℃.
Further preferably, the nylon powder prepared in the second step has a bulk density of 0.45-0.52 g/cc, a enthalpy value of 80-120J/g and a sintering window of 30-50 ℃.
Further preferably, the flow aid can be fumed silica, fumed alumina or nano titania.
The invention also provides a nylon powder material for selective laser sintering, which is characterized by being prepared by the preparation method of the nylon powder material for selective laser sintering.
In the field of selective laser sintering, nylon powder needs to be spread from a powder supply system to molding through a scraper or a roller, so that the flowability of nylon is important, and the flowability of the nylon powder mainly depends on the shape, the average particle size and the particle size distribution of the powder. If the sphericity of the nylon powder is higher, the average particle size is in a proper range, and the particle size distribution is narrower, the flowability of the powder is better, and the nylon powder is more favorably applicable to equipment for selective laser sintering. If the crystallization speed of the nylon powder is slower in the cooling process, the crystallization is more stable, the melting point of the nylon powder is higher, and the sintering window is wider (the sintering window is the difference between the starting point of the melting point of the powder and the ending point of the crystallization point of the powder). If the crystal form of the nylon powder is more stable, the enthalpy value of the nylon powder is higher, and the thermal property of the nylon powder is more stable, the nylon powder is less prone to be melted when being in contact with a melt melted by laser, and the workpiece surface prepared in the condition is better.
The nylon powder is subjected to a proper cryogenic grinding process to obtain the nylon powder with proper particle size. However, the nylon powder prepared by cryogenic grinding has irregular shape, poor sphericity, wide particle size distribution, wide radius distance and narrow sintering window, thereby limiting the application of the nylon powder in the selective laser sintering technology. The invention sieves and grades the cryogenic nylon powder to obtain micron-sized powder. After passing through the heat treatment tower, the sphericity of the powder is improved, the diameter distance of the nylon powder is reduced, the fluidity of the powder is increased, the crystallization performance of the nylon powder is improved, and the enthalpy value and the sintering window of the nylon powder are improved. In the heat treatment tower, when the nylon powder in the heating area is heated to a higher temperature above the melting point, the surface of the nylon powder can be in a viscous flow state at a high temperature state, and in the state, the surface of the nylon powder is in a form capable of performing plastic irreversible deformation under the action of external force. The viscous flow state of nylon has the similar fluidity of low molecular liquid, so that pressure difference can be formed on the upper surface and the lower surface of nylon powder under the action of surface tension in the descending process of the nylon powder. Thus, the irregular upper and lower portions of the surface of the nylon powder are subjected to different forces, the surface of the nylon powder tends to be a smooth surface, and finally the powder is changed from irregular-shaped powder to nearly spherical or globular-shaped powder. The nylon powder in a viscous flow state can be isothermally crystallized when the heat preservation area is at a high temperature, and is very slowly cooled in the cooling process of the cooling area, and the five-section cooling process is adopted, so that the nylon powder can be crystallized more completely in the whole process to form a more stable crystal form. The melting point of the nylon powder can be improved, the sintering window of the nylon powder is improved, the enthalpy value of the nylon powder is also improved, and the nylon powder is more suitable for the field of selective laser sintering.
The invention provides a nylon powder material for selective laser sintering and a preparation method thereof, and the nylon powder material has the following beneficial effects: the nylon granules are subjected to cryogenic grinding and heat treatment in a heat treatment tower to obtain nylon powder with moderate particle size, narrow particle size distribution, high sphericity and good fluidity. Meanwhile, five-section cooling is carried out in the cooling stage in the heat treatment tower, the enthalpy value and the sintering window of the nylon powder can be improved, the nylon powder is suitable for the field of selective laser sintering, and a workpiece prepared from the nylon powder has good performance and surface.
Drawings
FIG. 1 is a DSC of a first comparative example in the preparation method of a nylon powder material for selective laser sintering according to the present invention;
FIG. 2 is a DSC of the first embodiment of the preparation method of nylon powder material for selective laser sintering according to the present invention.
Detailed Description
The present invention will be described in further detail below with reference to specific embodiments.
Comparative example 1
The method comprises the following steps: adding the nylon 1212 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, wherein the grinding temperature is-100 ℃, and the stirring speed is 2000 r/min. Then, the powder was sieved and classified to obtain nylon 1212 powder for selective laser sintering having an average particle diameter of 60 μm, a diametral distance of 1.9 and a bulk density of 0.39 g/cc. The enthalpy value of the nylon powder is 40J/g, the first melting point is 178 ℃, and the sintering window is 22 ℃.
Example one
The method comprises the following steps: adding the nylon 1212 granular material into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, wherein the grinding temperature is-100 ℃, and the stirring speed is 2000r/min, so as to obtain nylon 1212 powder with the average particle size of 60 mu m, the radial distance of 1.9 and the apparent density of 0.39 g/cc. The enthalpy value of the nylon 1212 powder is 40J/g, the first melting point is 178 ℃, and the sintering window is 22 ℃.
Step two: adding the cryogenic crushed nylon 1212 powder from the top of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and the descending speed and the temperature of the powder of each section of area can be controlled differently. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 208 ℃, and the descending speed of the powder is 1 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set to be 213 ℃, and the powder descending speed is 8 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 20m/h, and the height is 2 m; the cooling second section is 15m/h and the height is 2 m; the third cooling section is 12m/h and the height is 2 m; the second cooling section is 9m/h and the height is 2 m; the second cooling stage is 6m/h and the height is 2 m. The nylon 1212 powder obtained had an average particle diameter of 58 μm, a caliper of 0.8 and a bulk density of 0.5 g/cc. The enthalpy value of the nylon 1212 powder is 96J/g, the second melting point is 187 ℃, and the sintering window is 31 ℃.
Step three: and (3) sieving and grading the nylon 1212 powder, and adding a fumed silica flow aid to obtain the nylon 1212 powder for selective laser sintering.
Example two
The method comprises the following steps: adding nylon 12 into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at-120 ℃, and stirring at a speed of 3000r/min to obtain polyurethane powder. Then, the mixture was sieved and classified to obtain a polyurethane powder having an average particle diameter of 45 μm, a pitch of 2.1 and a bulk density of 0.38 g/cc. The enthalpy value of the nylon 12 powder is 30J/g, the first melting point is 177 ℃, and the sintering window is 21 ℃.
Step two: adding the cryogenic crushed nylon 12 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and the descending speed and the temperature of the powder of each section of area can be controlled differently. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 207 ℃, and the descending speed of the powder is 1.5 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set at 212 ℃, and the powder descending speed is 10 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 18m/h, and the height is 2 m; the second cooling section is 14m/h and the height is 2 m; the third cooling section is 11m/h and the height is 2 m; the second cooling section is 8m/h and the height is 2 m; the second cooling stage is 5m/h and the height is 2 m. The nylon 12 powder obtained had an average particle diameter of 42 μm, a diametral distance of 0.9, a bulk density of 0.45g/cc, a enthalpy of 98J/g, a second melting point of 186 ℃ and a sintering window of 30 ℃.
Step three: and (3) sieving and grading the nylon 12 powder, and adding a fumed silica flow aid to obtain the nylon 12 powder for selective laser sintering.
EXAMPLE III
The method comprises the following steps: adding the nylon 1010 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at-100 ℃, and stirring at a speed of 3000r/min to obtain nylon 1010 powder. Then, the nylon 1010 powder with the average grain diameter of 50 mu m and the diameter distance of 1.9 is obtained by sieving and grading. The enthalpy value of the nylon 1010 powder is 36J/g, the first melting point is 195 ℃, and the sintering window is 23 ℃.
Step two: adding the cryogenic crushed nylon 1010 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and the descending speed and the temperature of the powder of each section of area can be controlled differently. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 225 ℃, and the descending speed of the powder is 1.3 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set at 230 ℃, and the powder descending speed is 8 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 17m/h, and the height is 2 m; the second cooling section is 13m/h and the height is 2 m; the third cooling section is 10m/h and the height is 2 m; the second cooling section is 8m/h and the height is 2 m; the second cooling section is 4m/h and the height is 2 m. The nylon 1010 powder obtained had an average particle diameter of 48 μm, a diametral distance of 0.8 and a bulk density of 0.46 g/cc. The enthalpy value of the nylon 1010 powder is 80J/g, the second melting point is 205 ℃, and the sintering window is 33 ℃.
Step three: and (3) sieving and grading the nylon 1010 powder, and adding a fumed silica flow aid to obtain the nylon 1010 powder for selective laser sintering.
Example four
The method comprises the following steps: adding the nylon 11 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at the temperature of minus 100 ℃, and stirring at the speed of 2500r/min to obtain nylon 11 powder. Then, the powder was sieved and classified to obtain nylon 11 powder having an average particle diameter of 70 μm, a pitch of 1.8 and a bulk density of 0.42 g/cc. The enthalpy value of the nylon 11 powder is 42J/g, the first melting point is 192 ℃, and the sintering window is 27 ℃.
Step two: adding the cryogenic crushed nylon 11 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and each section of area can control the falling speed and the temperature of different powders. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 222 ℃, and the descending speed of the powder is 1.1 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set to be 227 ℃, and the powder descending speed is 7 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 15m/h, and the height is 2 m; the second cooling section is 12m/h and the height is 2 m; the third cooling section is 9m/h and the height is 2 m; the second cooling section is 6m/h and the height is 2 m; the second cooling section is 3m/h and the height is 2 m. The nylon 11 powder obtained had an average particle diameter of 67 μm and a pitch of 0.7. The enthalpy value of the nylon 11 powder is 93J/g, the second melting point is 215 ℃, and the sintering window is 50 ℃.
Step three: and (3) sieving and grading the nylon 11 powder, and adding a fumed silica flow aid to obtain the nylon 11 powder for selective laser sintering.
EXAMPLE five
The method comprises the following steps: adding the nylon 612 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at the temperature of minus 80 ℃, and stirring at the speed of 1500r/min to obtain nylon 612 powder. Then, the mixture was sieved and classified to obtain nylon 612 powder having an average particle diameter of 80 μm, a diametral distance of 1.5 and a bulk density of 0.45 g/cc. The enthalpy value of the nylon 612 powder is 50J/g, the first melting point is 203 ℃, and the sintering window is 27 ℃.
Step two: adding the cryogenic crushed nylon 612 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and the descending speed and the temperature of the powder of each section of area can be controlled differently. In the first zone heating stage, the total height of the powder is 1m, the temperature is set to 233 ℃, and the descending speed of the powder is 0.9 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set at 238 ℃, and the powder descending speed is 6 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 18m/h, and the height is 2 m; the second cooling section is 14m/h and the height is 2 m; the third cooling section is 11m/h and the height is 2 m; the second cooling section is 8m/h and the height is 2 m; the second cooling stage is 5m/h and the height is 2 m. The nylon 612 powder obtained had an average particle diameter of 75 μm, a diametral distance of 0.6 and a bulk density of 0.52 g/cc. The enthalpy value of the nylon 612 powder is 102J/g, the second melting point is 217 ℃, and the sintering window is 41 ℃.
Step three: and (3) sieving and grading the nylon 612 powder, and adding a fumed silica flow aid to obtain the nylon 612 powder for selective laser sintering.
EXAMPLE six
The method comprises the following steps: adding the nylon 610 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at-100 ℃, and stirring at 2000r/min to obtain nylon 610 powder. Then, the powder was sieved and classified to obtain nylon 610 powder having an average particle diameter of 60 μm, a diametral pitch of 1.7 and a bulk density of 0.4 g/cc. The enthalpy value of the nylon 610 powder is 38J/g, the first melting point is 211 ℃, and the sintering window is 27 ℃.
Step two: adding the cryogenic crushed nylon 610 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and each section of area can control different powder falling speeds and powder temperatures. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 241 ℃, and the descending speed of the powder is 0.7 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set at 246 ℃, and the powder descending speed is 5 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 17m/h, and the height is 2 m; the second cooling section is 13m/h and the height is 2 m; the third cooling section is 10m/h and the height is 2 m; the second cooling section is 7m/h and the height is 2 m; the second cooling section is 4m/h and the height is 2 m. The nylon 610 powder obtained had an average particle diameter of 58 μm, a diametral distance of 0.8 and a bulk density of 0.51 g/cc. The enthalpy value of the nylon 610 powder is 108J/g, the second melting point is 218 ℃, and the sintering window is 34 ℃.
Step three: and (3) sieving and grading the nylon 610 powder, and adding a fumed silica flow aid to obtain the nylon 610 powder for selective laser sintering.
EXAMPLE seven
The method comprises the following steps: adding the nylon 6 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at-100 ℃, and stirring at 2000r/min to obtain nylon 6 powder. Then, the mixture was sieved and classified to obtain nylon 6 powder having an average particle diameter of 60 μm, a diametral distance of 1.7 and a bulk density of 0.4 g/cc. The enthalpy value of the nylon 6 powder is 39J/g, the first melting point is 219 ℃, and the sintering window is 28 ℃.
Step two: adding the cryogenic crushed nylon 6 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and the descending speed and the temperature of different powders can be controlled in each section of area. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 249 ℃, and the descending speed of the powder is 0.5 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set at 254 ℃, and the powder descending speed is 3 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 17m/h, and the height is 2 m; the second cooling section is 13m/h and the height is 2 m; the third cooling section is 10m/h and the height is 2 m; the second cooling section is 7m/h and the height is 2 m; the second cooling section is 4m/h and the height is 2 m. The nylon 6 powder obtained had an average particle diameter of 59 μm, a diametral distance of 0.9 and a bulk density of 0.52 g/cc. The enthalpy value of the nylon 6 powder is 114J/g, the second melting point is 226 ℃, and the sintering window is 35 ℃.
Step three: and (3) sieving and grading the nylon 6 powder, and adding a fumed silica flow aid to obtain the nylon 6 powder for selective laser sintering.
Example eight
The method comprises the following steps: adding the nylon 66 granules into a cryogenic grinder, introducing liquid nitrogen, starting the cryogenic grinder, grinding at the temperature of minus 100 ℃, and stirring at the speed of 2000r/min to obtain nylon 66 powder. Then, the powder was sieved and classified to obtain nylon 66 powder having an average particle diameter of 60 μm, a pitch of 1.7 and a bulk density of 0.4 g/cc. The enthalpy value of the nylon 66 powder is 40J/g, the first melting point is 256 ℃, and the sintering window is 30 ℃.
Step two: adding the cryogenic crushed nylon 66 powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections of areas, and each section of area can control the falling speed of different powders and the temperature of the powders. In the first zone heating stage, the total height of the powder is 1m, the temperature is set at 300 ℃, and the descending speed of the powder is 1 m/h; in the second region heat preservation stage, the total height is 20m, the temperature is set at 300 ℃, and the powder descending speed is 8 m/h; a third zone cooling stage, the height is 10m, the first cooling stage is 17m/h, and the height is 2 m; the second cooling section is 13m/h and the height is 2 m; a third zone cooling stage, the height is 10m, the first cooling stage is 17m/h, and the height is 2 m; the second cooling section is 13m/h and the height is 2 m; the third cooling section is 10m/h and the height is 2 m; the second cooling section is 7m/h and the height is 2 m; the second cooling section is 4m/h and the height is 2 m. The nylon 66 powder obtained had an average particle diameter of 58 μm, a diametral distance of 0.8 and a bulk density of 0.49 g/cc. The enthalpy value of the nylon 66 powder is 120J/g, the second melting point is 266 ℃, and the sintering window is 40 ℃.
Step three: and (3) sieving and grading the nylon 66 powder, and adding a fumed silica flow aid to obtain the nylon 66 powder for selective laser sintering.
The radius distance in the examples of the present invention is (D90-D10)/D50, and the term represents the distribution of the particle diameters of the powder. The sintering window, which is the melting point peak starting point-crystallization peak ending point, represents the range of values that the sintering temperature can be set, the wider the sintering window, the more favorable the sintering of the powder, the specific parameters of the preparation method of the nylon powder material prepared by the invention are shown in table 1-2, fig. 1 is a DSC diagram of comparative example one, and fig. 2 is a DSC diagram of example one.
TABLE 1 parameter Table of nylon powder prepared in the first step of the process for preparing nylon powder material for selective laser sintering according to the present invention
TABLE 2 parameter table of nylon powder prepared in step two of the method for preparing nylon powder material for selective laser sintering of the present invention
Claims (10)
1. A preparation method of a nylon powder material for selective laser sintering is characterized by comprising the following steps:
the method comprises the following steps: the nylon granules are subjected to a deep cooling crushing process and a grading sieving process to prepare nylon powder with the average particle size of 50-75 microns and the diameter distance of 0.6-1.5;
step two: adding the polymer powder from the top end of a heat treatment tower, wherein the heat treatment tower is vertically arranged, the heat treatment tower comprises three sections, namely a heating area, a heat preservation area and a cooling area, which are sequentially arranged from top to bottom, the cooling area adopts a five-section cooling process, and after the nylon powder passes through the three sections, the nylon powder with the average particle size of 50-75 mu m and the radial distance of 0.6-1.5 is prepared;
step three: and D, adding a flow aid into the nylon powder obtained in the step two after a grading sieving process is carried out on the nylon powder, and obtaining the nylon powder for selective laser sintering.
2. The preparation method of the nylon powder material for selective laser sintering according to claim 1, wherein the total powder height of the heating region is 1m, the heating temperature is 200-300 ℃, and the powder descending speed is 0.5-1.5 m/h; the total height of the powder in the heat preservation area is 20m, the heat preservation temperature is 200-300 ℃, and the powder descending speed is 3-10 m/h.
3. The method for preparing nylon powder material for selective laser sintering according to claim 1, wherein the total powder height of the cooling region is 10m, and the powder descending speed is 3-40 m/h.
4. The preparation method of the nylon powder material for selective laser sintering according to claim 3, wherein the five-stage cooling process adopted by the cooling area specifically comprises: the descending speed of the powder in the first stage of cooling is 15-20 m/h, and the total height of the powder is 2 m; the descending speed of the second stage of cooling powder is 12-15 m/h, and the total height of the powder is 2 m; the descending speed of the powder in the third stage of cooling is 9-12 m/h, and the total height of the powder is 2 m; the descending speed of the fourth stage of powder is 6-9 m/h, and the total height of the powder is 2 m; the descending speed of the powder in the fifth stage of cooling is 3-6 m/h, and the total height of the powder is 2 m.
5. The method for preparing nylon powder material for selective laser sintering according to claim 4, wherein the nylon granules are nylon 1212, nylon 12, nylon 1010, nylon 11, nylon 612, nylon 610, nylon 6 or nylon 66 granules.
6. The method for preparing nylon powder material for selective laser sintering according to claim 5, wherein the cryogenic pulverization process is as follows: adding the nylon granules into a cryogenic crusher, introducing liquid nitrogen, starting the cryogenic crusher, wherein the crushing temperature is-120 to-80 ℃, and the stirring speed is 1500 to 3000 r/min.
7. The method for preparing nylon powder material for selective laser sintering according to claim 6, wherein the nylon powder prepared in the first step has a bulk density of 0.38-0.45 g/cc, a enthalpy of 30-50J/g, and a sintering window of 20-30 ℃.
8. The method for preparing nylon powder material for selective laser sintering according to claim 7, wherein the nylon powder prepared in step two has a bulk density of 0.45-0.52 g/cc, a enthalpy of 80-120J/g, and a sintering window of 30-50 ℃.
9. The method for preparing nylon powder material for selective laser sintering according to claim 8, wherein the flow promoter is fumed silica, fumed alumina or nano titanium dioxide.
10. A nylon powder material for selective laser sintering, which is prepared by the preparation method of the nylon powder material for selective laser sintering according to any one of claims 1 to 9.
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| KR20080083873A (en) * | 2007-03-13 | 2008-09-19 | 주식회사 라이온켐텍 | Laser sintering powders using nylon 6, manufacturing method thereof and molded product obtained from the same powder |
| CN106478964A (en) * | 2015-08-28 | 2017-03-08 | 比亚迪股份有限公司 | A kind of nylon powder and preparation method thereof and nylon composite materials |
| CN107033373A (en) * | 2017-06-01 | 2017-08-11 | 深圳市业天科技有限公司 | A kind of preparation method and applications of PA6 powder for selective laser sintering |
| CN107337793A (en) * | 2017-07-28 | 2017-11-10 | 湖南华曙高科技有限责任公司 | Copolymer nylon dusty material for selective laser sintering and preparation method thereof |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20080083873A (en) * | 2007-03-13 | 2008-09-19 | 주식회사 라이온켐텍 | Laser sintering powders using nylon 6, manufacturing method thereof and molded product obtained from the same powder |
| CN106478964A (en) * | 2015-08-28 | 2017-03-08 | 比亚迪股份有限公司 | A kind of nylon powder and preparation method thereof and nylon composite materials |
| CN107033373A (en) * | 2017-06-01 | 2017-08-11 | 深圳市业天科技有限公司 | A kind of preparation method and applications of PA6 powder for selective laser sintering |
| CN107337793A (en) * | 2017-07-28 | 2017-11-10 | 湖南华曙高科技有限责任公司 | Copolymer nylon dusty material for selective laser sintering and preparation method thereof |
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