A moisturizing method for an additive manufacturing print head

Abstract

The application discloses a moisturizing method for additive manufacturing printing nozzle, and relates to the field of additive manufacturing. The moisturizing method comprises the following steps: adding an external additive into an adhesive composition for additive manufacturing printing nozzle, uniformly mixing at normal temperature, loading into an ink cartridge, and spraying by the additive manufacturing printing nozzle; the external additive is a fatty alcohol polyoxyethylene ether, and the structural formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O) n H, wherein R is a C8-C 22 hydrocarbon group, and n=6-20. By adding a certain amount of fatty alcohol polyoxyethylene ether into the adhesive composition, a certain thickness of dense film-like substance can be rapidly formed on the surface of the adhesive composition to seal the nozzle, so that the volatilization of solvent in the adhesive composition in the printing nozzle is prevented, and the purpose of moisturizing the printing nozzle is achieved; and when the nozzle is used, the film-like substance at the nozzle can be broken under normal pressure, so that the normal production efficiency of additive manufacturing and the green strength during printing are effectively ensured.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing, and in particular to a moisturizing method for additive manufacturing printheads. Background Technology

[0002] Additive manufacturing, commonly known as 3D printing, is a rapidly developing emerging technology in the manufacturing sector. Currently, additive manufacturing technology relies on cutting-edge technologies from multiple disciplines and has found applications in fields such as aerospace technology, automotive and home appliance manufacturing, biomedicine, and food processing.

[0003] Currently, the binder-jet metal printing process used for metal materials involves depositing metal powder into a build chamber, then compacting a layer of powder on a printing platform using a powder spreader. A print head with inkjet nozzles moves above the platform, selectively depositing binder droplets onto the desired shape of the metal powder. After one layer is printed, the build platform moves downwards, and the process is repeated, using the binder to bond the powdered metal material layer by layer until the metal part is complete. During this printing process, solvent evaporation from the binder composition used for jetting can cause nozzle clogging or print head drying, leading to defects in the final printed part. To prevent nozzle clogging, a common method is to replace the binder composition with a humidifying solution added to the print head after printing, keeping the nozzle wet. One approach is to add a high-boiling-point solvent to the binder composition to extend the solvent's evaporation time, but this requires higher temperatures or longer curing times, reducing production efficiency. Another approach is to reduce the solids content in the binder composition and extend the solvent evaporation time, but this method carries the risk of insufficient green strength.

[0004] Therefore, it is of great significance to provide a moisturizing method for additive manufacturing printheads that does not affect production efficiency and green strength. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a moisturizing method for additive manufacturing printheads. By adding fatty alcohol polyoxyethylene ether to the adhesive composition, a dense film of a certain thickness can be rapidly formed on the surface of the adhesive composition to seal the nozzle, thereby achieving the purpose of moisturizing the nozzle. Specifically, this is achieved through the following techniques:

[0006] The present invention provides a moisturizing method for an additive manufacturing printhead, comprising the steps of: adding an external admixture to an adhesive composition for an additive manufacturing printhead, mixing it at room temperature, and loading it into an inkjet cartridge;

[0007] The external admixture is a fatty alcohol polyoxyethylene ether, and the structural formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O). n H, where R is C8~C22 Hydrocarbon groups, n = 6 to 20.

[0008] Furthermore, the amount of the above-mentioned fatty alcohol polyoxyethylene ether is 0.1% to 4% of the total amount of the adhesive composition.

[0009] Furthermore, the above-mentioned RO(CH2CH2O) n In the structural formula of H, R is C8~C 22 When the straight-chain hydrocarbon group n = 6 to 20, it can form a dense film of a certain thickness on the surface of the adhesive composition to seal the nozzle and achieve the purpose of moisturizing the nozzle.

[0010] Furthermore, the above-mentioned adhesive composition is an aqueous adhesive composition.

[0011] Further, based on parts by weight, the above-mentioned aqueous adhesive composition comprises: 55-90 parts water, 3-20 parts base adhesive, 5-30 parts water-miscible solvent, 1-25 parts humectant, and 0.01-5 parts surfactant.

[0012] Furthermore, the aforementioned base adhesive includes at least one of polyethylene, polyvinyl alcohol, polyvinylpyrrolidone, and polyurethane.

[0013] Furthermore, the aforementioned water-miscible solvents include at least one of ethanol, n-propanol, isopropanol, and diethylene glycol butyl ether.

[0014] Furthermore, the aforementioned moisturizers include polyols or polyethylene oxide.

[0015] Furthermore, the aforementioned polyols include at least one of ethylene glycol, propylene glycol, glycerol, butanediol, and polyethylene glycol.

[0016] Furthermore, the aforementioned surfactants include dimethyloctynediol or tetramethyldecyndiol.

[0017] Furthermore, the above-mentioned water-based adhesive composition also includes pH adjusters, chelating agents, and bactericides.

[0018] In the method disclosed in this invention, a certain amount of fatty alcohol polyoxyethylene ether is added to the adhesive composition, which can form a dense film of a certain thickness on the surface of the adhesive composition to seal the nozzle and prevent the solvent in the adhesive composition from evaporating, thereby achieving the purpose of moisturizing the nozzle. At the same time, the amount of fatty alcohol polyoxyethylene ether added affects the film formation. On the one hand, if the amount added is too low, a continuous film cannot be formed, which is insufficient to cover the surface of the adhesive composition, thus affecting the moisturizing effect; on the other hand, if the amount added is too high, the resulting film will have excessive strength, and normal pressure will not cause it to rupture, thus affecting the normal printing of additive manufacturing.

[0019] Compared with the prior art, the advantages of the present invention are:

[0020] 1. The present invention, by adding a certain amount of fatty alcohol polyoxyethylene ether to the adhesive composition, can rapidly form a dense film of a certain thickness on the surface of the adhesive composition to seal the nozzle, thereby preventing the solvent in the adhesive composition inside the print head from evaporating, thus achieving the purpose of moisturizing the print nozzle.

[0021] 2. When using the printhead, normal pressure will cause the film at the nozzle to rupture, effectively ensuring the normal production efficiency of additive manufacturing and the strength of the green body during printing. No cleaning or moisturizing is required after use. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The moisturizing method for additive manufacturing printheads disclosed in this invention includes the step of adding fatty alcohol polyoxyethylene ether to an adhesive composition for additive manufacturing printheads, wherein the fatty alcohol polyoxyethylene ether has the structural formula RO(CH2CH2O). n H, where R is C8~C 22 The hydrocarbon group, n = 6 to 20; the amount of fatty alcohol polyoxyethylene ether is 0.1% to 4% of the total amount of the adhesive composition; the adhesive composition is an aqueous adhesive composition, which includes: 55-90 parts water, 3-20 parts base adhesive, 5-30 parts water-miscible solvent, 1-25 parts humectant, and 0.01-5 parts surfactant.

[0024] In the above-mentioned aqueous adhesive composition, the base adhesive includes at least one of polyethylene, polyvinyl alcohol, polyvinylpyrrolidone, and polyurethane; the water-miscible solvent includes at least one of ethanol, n-propanol, isopropanol, and diethylene glycol butyl ether; the humectant includes a polyol or polyethylene oxide, and the polyol includes at least one of ethylene glycol, propylene glycol, glycerol, butanediol, and polyethylene glycol; the surfactant includes dimethyloctynediol or tetramethyldecynediol.

[0025] For ease of comparison, the specific structural formula of the fatty alcohol polyoxyethylene ether and the specific composition of the adhesive composition used in the examples and comparative examples are as follows:

[0026] Example 1

[0027] Fatty alcohol polyoxyethylene ether is added to an adhesive composition for additive manufacturing printheads, mixed at room temperature, and then added to an ink cartridge for ejection in the additive manufacturing printhead; the structural formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O). n H, where R is C 12 The linear alkyl group, n=9, and the fatty alcohol polyoxyethylene ether is 0.1% of the total amount of the adhesive composition.

[0028] The adhesive composition of this embodiment, by weight, comprises: 5 parts polyvinyl alcohol (Mw = 13000-23000, 88% degree of hydrolysis), 12 parts isopropanol, 8 parts glycerol, 3 parts dimethyloctyryne diol, and 72 parts deionized water.

[0029] Example 2

[0030] Fatty alcohol polyoxyethylene ether is added to an adhesive composition for additive manufacturing printheads, mixed at room temperature, and then added to an ink cartridge for ejection in the additive manufacturing printhead; the structural formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O). n H, where R is C 12 The linear alkyl group, n=15, and the fatty alcohol polyoxyethylene ether is 3% of the total amount of the adhesive composition.

[0031] The adhesive composition of this embodiment, by weight, comprises: 10 parts polyvinylpyrrolidone (Mw = 5500), 5 parts isopropanol, 16 parts ethylene glycol, 4 parts tetramethyldecynyl glycol, and 65 parts deionized water.

[0032] Example 3

[0033] Fatty alcohol polyoxyethylene ether is added to an adhesive composition for additive manufacturing printheads, mixed at room temperature, and then added to an ink cartridge for ejection in the additive manufacturing printhead; the structural formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O). n H, where R is C 18 The linear alkyl group, n=20, and the fatty alcohol polyoxyethylene ether is 4% of the total amount of the adhesive composition.

[0034] The adhesive composition of this embodiment, by weight, comprises: 15 parts polyurethane (Mw = 26000), 6 parts diethylene glycol butyl ether, 5 parts ethylene glycol, 4 parts tetramethyldecynyl glycol, and 70 parts deionized water.

[0035] Comparative Example 1

[0036] The formulation and dosage of the adhesive composition in this comparative example are the same as those in Example 1. The only difference is that the adhesive composition in this comparative example is directly added to the ink cartridge for use in additive manufacturing of the print head for spraying, without the addition of an external admixture: fatty alcohol polyoxyethylene ether.

[0037] Comparative Example 2

[0038] The formulation and dosage of the adhesive composition in this comparative example are the same as those in Example 1, except that the dosage of fatty alcohol polyoxyethylene ether in this comparative example is 7% of the total amount of the adhesive composition.

[0039] The methods disclosed in the above embodiments and comparative examples were applied to the RICOH MH5320 printhead for printhead clogging evaluation and green strength evaluation. Specifically, the printhead clogging evaluation involved printing, followed by resting the printhead for 24 hours, 7 days, and 30 days. The printhead was then wiped, pressurized, and the printhead status fluid was tested. Missing sections were counted (the printhead has 1280 nozzles), with one line corresponding to one nozzle. The number of missing lines was the number of clogged nozzles. The printhead clogging evaluation was performed according to the following criteria:

[0040] 1A: No missing lines were observed, indicating that the nozzle is not clogged;

[0041] 1B: The number of missing lines observed is less than or equal to 6, indicating that the nozzle blockage is very minor and there is no problem in practical use;

[0042] 1C: The number of missing lines observed is greater than 6 and less than or equal to 12, indicating that the nozzle is slightly clogged and there is no problem in practical use;

[0043] 1D: The number of missing lines is greater than 12, which poses a problem in practical use.

[0044] The green body strength evaluation is as follows: Print the part, place the green body in an oven and heat to 105℃ for 1 hour, then heat to 140℃ for 2 hours. Stop heating, cool to room temperature, and remove any powder outside the green body. Test the green body strength according to GB / T228.1-2010 Standard for Tensile Testing of Metallic Materials, and evaluate the green body strength according to the following standards:

[0045] 2A: Green strength greater than 6 MPa;

[0046] 2B: Green strength greater than 4 and less than or equal to 6 MPa indicates that vibration has no effect and there is no problem in practical use;

[0047] 2C: Green strength greater than 2 and less than or equal to 4 MPa indicates that slight vibration has no effect and there is no problem in practical use;

[0048] 2D: Green strength is less than or equal to 2MPa, which poses practical problems.

[0049] The results of the nozzle clogging evaluation and green body strength evaluation are shown in Table 1 below:

[0050]

[0051] As shown in the table above, the moisturizing method of this application can prevent the solvent evaporation of the adhesive composition inside the printhead, thereby achieving the purpose of moisturizing the nozzle and keeping it unclogged for a long time. From the working status of the printers after 30 days of nozzle placement in Example 1 and Comparative Example 2, it can be seen that when the amount of external admixture is too high, the strength of the formed film becomes too high, and pressure cannot rupture the film, thus affecting the normal printing of additive manufacturing. Only the moisturizing method defined in this application can keep the printhead unclogged for a long time. During use, normal pressure can rupture the film at the printhead, ensuring the normal production efficiency of additive manufacturing and the green strength during printing.

[0052] The above detailed embodiments describe the implementation of the present invention; however, the present invention is not limited to the specific details described in the above embodiments. Within the scope of the claims and technical concept of the present invention, various simple modifications and changes can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for moisturizing a printhead used in additive manufacturing, characterized in that, Add an admixture to the adhesive composition used for additive manufacturing printheads, mix well at room temperature, and then pack into an ink cartridge; The amount of the external admixture is 0.1% to 4% of the total amount of the adhesive composition; the external admixture is a fatty alcohol polyoxyethylene ether, and the structural formula of the fatty alcohol polyoxyethylene ether is RO(CH2CH2O). n H, where R is C8~C 22 Hydrocarbon groups, n=6~20.

2. The moisturizing method for an additive manufacturing printhead according to claim 1, characterized in that, The R is C8~C 22 Straight-chain hydrocarbon groups.

3. The moisturizing method for an additive manufacturing printhead according to claim 1, characterized in that, The adhesive composition is an aqueous adhesive composition.

4. The moisturizing method for an additive manufacturing printhead according to claim 3, characterized in that, The aqueous adhesive composition comprises, by weight parts: 55-90 parts water, 3-20 parts base adhesive, 5-30 parts water-miscible solvent, 1-25 parts humectant, and 0.01-5 parts surfactant.

5. The moisturizing method for an additive manufacturing printhead according to claim 4, characterized in that, The base adhesive includes at least one of polyethylene, polyvinyl alcohol, polyvinylpyrrolidone, and polyurethane.

6. The moisturizing method for an additive manufacturing printhead according to claim 4, characterized in that, The water-miscible solvent includes at least one of ethanol, n-propanol, isopropanol, and diethylene glycol butyl ether.

7. The moisturizing method for an additive manufacturing printhead according to claim 4, characterized in that, The humectant includes polyols or polyethylene oxide.

8. The moisturizing method for an additive manufacturing printhead according to claim 4, characterized in that, The surfactant includes dimethyloctynediol or tetramethyldecyndiol.

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