Preparation method of polymer binder coated 316L powder

Abstract

The invention discloses a preparation method of 316L powder coated with a macromolecular binder, and belongs to the technical field of 3D printing, and the preparation method comprises the following steps: S1, weighing 316L powder and binder powder with certain mass according to the mass ratio of 9: 1, 8: 2, 7: 3 and 6: 4; s2, physically mixing the powder to obtain 316L / binder mixed powder; s3, under the inert gas condition, the obtained 316L / binder mixed powder is heated and stirred in a solvent, and suspension liquid is obtained; s4, slowly cooling the suspension, and filtering and drying the precipitate to obtain a 316L / binder block; s5, the 316L / binder block is ground and sieved, and 316L powder coated with a binder is obtained; according to the method, the 316L powder coated with the high-molecular binder can be successfully applied to selective laser sintering forming, the input energy of selective laser sintering is reduced, a supporting structure does not need to be added in the printing process, and the performance of a printed green body meets the machining requirements of subsequent procedures.

Description

Technical Field

[0001] The present invention belongs to the field of 3D printing technology, and in particular relates to a method for preparing 316L powder coated with a polymer binder. Background Art

[0002] 316L powder is an alloy powder commonly used in the 3D printing industry. When using selective laser melting to print 316L metal parts, the laser energy consumption of melting the metal is relatively high, and the printed green body requires an additional support structure. Combining a binder with 316L metal powder and using selective laser sintering of 316L / binder composite powder can effectively reduce laser energy, and the green body does not need to be printed with a support structure. Degreasing, heat treatment and post-processing of the printed green body can produce metal parts with performance basically consistent with SLM metal parts.

[0003] Currently, the main preparation methods of 316L / binder composite powder are mixing method and coating method. The mixing method uses mixing equipment to mechanically mix the polymer binder and 316L metal powder. However, the mixed powder is easy to separate, resulting in large pore defects in the green body of selective laser sintering. Therefore, a preparation method of 316L powder coated with a polymer binder is needed to solve the above problems. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing polymer binder-coated 316L powder to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for preparing 316L powder coated with a polymer binder, comprising the following steps:

[0006] S1. Weigh a certain amount of 316L powder and binder powder in the following mass ratios: 9:1, 8:2, 7:3, and 6:4;

[0007] S2. Physically mix the above powders to obtain 316L / binder mixed powder;

[0008] S3. Under inert gas conditions, the obtained 316L / binder mixed powder is heated and stirred in a solvent to obtain a suspension;

[0009] S4. Slowly cool the suspension, filter and dry the precipitate to obtain 316L / binder blocks;

[0010] S5. Grind and sieve the 316L / binder block to obtain binder-coated 316L powder.

[0011] By setting up the above steps, 316L powder coated with a polymer binder can be successfully used in selective laser sintering molding. This not only reduces the input energy of selective laser sintering, but also eliminates the need for adding support structures during the printing process. The performance of the printed green body meets the requirements of post-process processing.

[0012] As a preferred solution, in "Step S1", the binder powder is a combination of one or more of epoxy resin, polymethyl methacrylate, stearic acid, polylactic acid, polyethylene glycol, phenolic resin, polystyrene, polypropylene, and ethylene-vinyl acetate copolymer.

[0013] As a preferred solution, in "Step S2", the 316L powder and the binder are first mixed using a V-type mixer with an equipment speed of 10-25 r / min and a mixing time of 6-12 h to obtain a 316L / binder mixed powder.

[0014] As a preferred solution, in "Step S3", the solvent is a combination of one or more of ethanol, ethyl acetate, acetone, and dichloroethane.

[0015] As a preferred solution, in "step S3", the heating temperature is 40-70°C and the stirring speed is 300 r / min.

[0016] As a preferred solution, in "Step S4", the suspension is naturally cooled to room temperature, and the dissolved binder is precipitated on the surface of the 316L powder. After the temperature drops to room temperature, the precipitate is filtered and dried to obtain a block-shaped 316L / binder material.

[0017] As a preferred solution, in "Step S5", the 316L / binder block is placed in a mortar and ground, and the ground powder is sieved using a 200-mesh sieve to obtain a 316L / binder coated powder.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] In the present invention, the 316L powder coated with a polymer binder can be successfully applied to selective laser sintering molding, which not only reduces the input energy of selective laser sintering, but also does not require the addition of a support structure during the printing process, and the performance of the green body after printing meets the requirements of subsequent processing steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process of the present invention;

[0021] Figure 2 This is a comparison chart of the basic properties of 316L and 316L / stearic acid composite powders of the present invention;

[0022] Figure 3This is the morphological diagram of the 316L / stearic acid powder of the present invention. Detailed implementation mode

[0023] The following further describes the present invention in conjunction with embodiments.

[0024] The following embodiments are used to illustrate the present invention, but cannot be used to limit the protection scope of the present invention. The conditions in the embodiments can be further adjusted according to specific conditions. Any simple improvement of the method of the present invention under the premise of the concept of the present invention belongs to the scope protected by the present invention.

[0025] Please refer to Figures 1-3 , the present invention provides a preparation method of 316L powder coated with a polymer binder, including the following steps:

[0026] S1. Weigh a certain mass of 316L powder and binder powder, and the mass ratios are 9:1, 8:2, 7:3, and 6:4;

[0027] In "Step S1", the binder powder is one or a combination of more than one of epoxy resin, polymethyl methacrylate, stearic acid, polylactic acid, polyethylene glycol, phenolic resin, polystyrene, polypropylene, ethylene-vinyl acetate copolymer;

[0028] S2. Physically mix the above powders to obtain 316L / binder mixed powder;

[0029] In "Step S2", first mix the 316L powder and the binder with a V-type mixer, the equipment rotation speed is 10 - 25 r / min, and the mixing time is 6 - 12 h to obtain 316L / binder mixed powder;

[0030] S3. Under the condition of inert gas, heat and stir the obtained 316L / binder mixed powder in a solvent to obtain a suspension;

[0031] In "Step S3", the solvent is one or a combination of more than one of ethanol, ethyl acetate, acetone, and dichloroethane;

[0032] In "Step S3", the heating temperature is 40 - 70 °C, and the stirring speed is 300 r / min;

[0033] S4. Slowly cool the suspension, filter and dry the precipitate to obtain a 316L / binder mass;

[0034] In "Step S4", let the suspension naturally cool to room temperature, and the dissolved binder precipitates on the surface of the 316L powder. After the temperature drops to room temperature, filter and dry the precipitate to obtain a massive 316L / binder;

[0035] S5. Grind and sieve the 316L / binder mass to obtain binder-coated 316L powder;

[0036] In "Step S5", put the 316L / binder mass into a mortar for grinding, and sieve the ground powder through a 200-mesh sieve to obtain binder-coated 316L powder;

[0037] By setting the above steps, the 316L powder coated with a polymer binder can be successfully applied to selective laser sintering forming, which not only reduces the input energy of selective laser sintering, but also does not require adding a support structure during the printing process, and the green body performance after printing meets the processing requirements of subsequent processes.

[0038] The working principle and usage process of the present invention: Put 316L powder and stearic acid powder (mass ratio 7:3) into a V-type mixer, with the equipment rotation speed of 20 r / min, and mix for 10 h to obtain 316L / stearic acid mixed powder;

[0039] Add ethanol to the mixed powder, with the stirring speed of 300 r / min, to obtain 316L / stearic acid suspension;

[0040] Heat the suspension to 60 °C and keep it warm for 30 min;

[0041] After the heat preservation ends, let the suspension cool to room temperature naturally, precipitate 316L / stearic acid precipitate, and filter and dry it;

[0042] Grind the dried 316L / stearic acid precipitate in a mortar, and sieve the ground powder through a 200-mesh sieve to obtain 316L / stearic acid composite powder;

[0043] By comparing the basic properties of 316L and 316L / stearic acid composite powder, and observing the morphology of 316L / stearic acid powder by SEM, it can be clearly seen that there is a film formed by stearic acid on the surface of 316L powder.

[0044] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A preparation method of 316L powder coated with a polymer binder, characterized in that: The following steps are involved: S1. Weigh a certain amount of 316L powder and binder powder in the following mass ratios: 9:1, 8:2, 7:3, and 6:4; S2. Physically mix the above powders to obtain 316L / binder mixed powder; S3. Under inert gas conditions, the obtained 316L / binder mixed powder is heated and stirred in a solvent to obtain a suspension; S4. Slowly cool the suspension, filter and dry the precipitate to obtain 316L / binder blocks; S5. Grind and sieve the 316L / binder block to obtain binder-coated 316L powder.

2. The preparation method of a polymer binder-coated 316L powder according to claim 1, characterized in that: In "step S1", the binder powder is one or more combinations of epoxy resin, polymethyl methacrylate, stearic acid, polylactic acid, polyethylene glycol, phenolic resin, polystyrene, polypropylene, and ethylene-vinyl acetate copolymer.

3. The preparation method of a 316L powder coated with a polymer binder according to claim 1, characterized in that: In "step S2", the 316L powder and the binder are first mixed using a V-type mixer at a speed of 10-25 r / min for 6-12 h to obtain a 316L / binder mixed powder.

4. The preparation method of a 316L powder coated with a polymer binder according to claim 1, characterized in that: In "step S3", the solvent is a combination of one or more of ethanol, ethyl acetate, acetone, and dichloroethane.

5. The preparation method of a 316L powder coated with a polymer binder according to claim 1, characterized in that: In "step S3", the heating temperature is 40-70°C and the stirring speed is 300 r / min.

6. The preparation method of a 316L powder coated with a polymer binder according to claim 1, characterized in that: In "step S4", the suspension is cooled to room temperature naturally, and the dissolved binder is precipitated on the surface of the 316L powder. After the temperature is reduced to room temperature, the precipitate is filtered and dried to obtain a block of 316L / binder.

7. The preparation method of a 316L powder coated with a polymer binder according to claim 1, characterized in that: In "step S5", the 316L / binder block was placed in a mortar and ground, and the ground powder was sieved using a 200-mesh sieve to obtain a 316L / binder coated powder.

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