Efficient recovery method for binder jet 3D printing ceramic powder

Abstract

The invention discloses an efficient recovery method for binder jet 3D printing ceramic powder. The efficient recovery method comprises the following steps that unbonded ceramic powder in a printer is collected to serve as powder to be recovered; performing microwave drying on the to-be-recycled ceramic powder; and the dried ceramic powder is subjected to multi-stage screening and sealed storage, and recycled ceramic powder is obtained. Rapid and uniform dehydration of ceramic powder is achieved through microwave drying, humidity consistency is remarkably improved, and compared with traditional hot air drying, heating time is short, and energy consumption is low; the particle size distribution is optimized by a multi-stage screening system, and the uniformity of a printing layer and the permeability stability of a binder are ensured; and powder moisture regaining is inhibited through sealed storage, and the recycling rate reaches 85% or above. The whole process can effectively solve the problem of non-uniform humidity and granularity of the recycled powder, so that the precision, mechanical property and batch consistency of a printed finished product are improved, and the process is suitable for efficient manufacturing of complex ceramic parts.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing and powder recycling, and particularly to an efficient recycling method for binder jet 3D printing ceramic powder. Background Art

[0002] Compared with other 3D printing technologies, binder jetting has wide material applicability (in principle, applicable to any material), high material utilization rate, and high printing efficiency, and is widely used in the preparation of complex-structured ceramic products. The unbonded powder during printing can serve as a natural support structure, eliminating the processes of adding and removing supports. On the other hand, the unbonded powder can be recycled for repeated printing after recovery, improving the utilization rate of ceramic powder and reducing the raw material cost, providing a green and economical solution for ceramic 3D printing.

[0003] Currently, there are problems such as uneven humidity and inconsistent particle size distribution in the recycling of binder jetting ceramic powder, resulting in an increased printing failure rate. Specifically, powders with higher humidity are prone to caking, and the powder fluidity decreases, causing problems such as printing interruption, uneven powder bed density, and abnormal binder diffusion. Inconsistent particle size distribution will lead to a decrease in powder bed density and strength, an increase in surface roughness, stress concentration and deformation during the sintering process. In addition, large particles will cause wear to the powder spreading roller or scraping plate, and fine powder dust is easy to clog the nozzle and contaminate the equipment.

[0004] Therefore, there is an urgent need to find an efficient recycling method for binder jet 3D printing ceramic powder. Summary of the Invention

[0005] The present invention aims to solve the problems of uneven humidity and inconsistent particle size distribution in the current recycling of binder jetting ceramic powder, which lead to an increased printing failure rate, and provides an efficient recycling method for binder jet 3D printing ceramic powder.

[0006] To achieve the above technical objectives, the technical solution provided by the present invention is as follows:

[0007] An efficient recycling method for binder jet 3D printing ceramic powder, comprising the following steps:

[0008] Step 1: Collect the unbonded ceramic powder as the powder to be recycled;

[0009] Step 2: Microwave-dry the ceramic powder to be recycled;

[0010] Step 3: Multistage screen and seal the dried ceramic powder to obtain recycled ceramic powder.

[0011] Specifically, the unbonded ceramic powder includes, but is not limited to, that sourced from the working box after each batch of printing, the equipment sand storage hopper, and the sand spreading device. The unbonded ceramic powder is centrally collected into a bucket, where the type of powder and the number of uses are stored and marked.

[0012] Further, the ceramic powder is one or more of alumina, zirconia, quartz, ceramsite sand, yttrium oxide, silicon carbide, and silicon nitride.

[0013] Further, in step 2, the microwave power is 6 - 10 kW, and the microwave heating time is 40 - 90 minutes, with the energy consumption reduced as much as possible on the premise of ensuring uniform drying of the ceramic powder.

[0014] Further, in step 2, the depth of the microwave drying working box is 300 mm. To increase the single - time powder drying capacity while ensuring the drying quality, the depth of the ceramic powder for microwave drying in the working box is 200 - 250 mm.

[0015] Further, in step 3, the specific method of multi - stage screening includes adding the dried powder into a two - stage vibrating screen, which includes a coarse screen and a fine screen, to remove large particles on the coarse screen and fine powder under the fine screen.

[0016] Further, the mesh number of the coarse screen is 70 - 180 meshes, and the mesh number of the fine screen is 200 - 325 meshes.

[0017] The present invention has the following beneficial effects:

[0018] The present invention realizes rapid and uniform dehydration of ceramic powder through microwave drying, significantly improving the humidity consistency. Compared with traditional hot - air drying, it has a short heating time and low energy consumption; the multi - stage screening system optimizes the particle size distribution, ensuring the uniformity of the printed layer and the stability of binder penetration; sealed storage inhibits powder moisture absorption, and the recycling rate reaches more than 85%. The overall process can effectively solve the problems of uneven humidity and particle size of recycled powder, thereby improving the precision, mechanical properties, and batch consistency of printed products, and is suitable for the efficient manufacturing of complex ceramic parts. Description of the Drawings

[0019] Figure 1 It is a process flow chart. Detailed Embodiments

[0020] The technical solutions of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work fall within the scope of protection of the present invention.

[0021] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Example 1

[0023] As Figure 1 shown in the process flow chart, the alumina ceramic powder is recycled, and the specific method steps are as follows:

[0024] Powder collection: Alumina powder printing is adopted, and the unbonded ceramic powder in the working box after the first printing, the ceramic powder in the equipment sand storage hopper, and the ceramic powder in the sand spreading device are collected as the same type of powder and stored in a bucket.

[0025] Microwave drying: The collected alumina powder is added to the microwave drying working box, the powder depth is 200 mm, the microwave power is 9.6 kW, and the microwave heating is carried out for 20 cycles. Each cycle includes 3 minutes of microwave heating + 2 minutes of pause.

[0026] Specifically, the 2-minute pause is to avoid possible local overheating, further improve the uniformity of the thermal field through heat diffusion, so as to improve the consistency of the powder humidity. After drying, it is cooled to below 50 °C for screening.

[0027] Multi-stage screening: The dried alumina powder is screened twice with 80-mesh and 200-mesh sieves, and the powder between 80 and 200 meshes is collected for printing use.

[0028] Sealed storage: In order to prevent the powder from absorbing moisture, the powder is placed in a container for sealed storage.

[0029] Comparative Example 1

[0030] The new alumina powder index is set as a comparative example.

[0031] In order to verify whether the alumina recovery obtained by the above method meets the use requirements, the angle of repose and bulk density of the recovered powder were detected, and at the same time, the recovered powder was used for printing and the density and dimensional accuracy of the samples were measured. As can be seen from Table 1 below, the parameters such as the angle of repose and bulk density of the recovered alumina powder meet the internal control requirements, and the density and dimensional accuracy of the printed samples also meet the requirements.

[0032] Table 1 Related parameters of Example 1 and Comparative Example 1

[0033]

[0034] Example 2

[0035] The zirconia ceramic powder is recycled, and the specific method steps are as follows:

[0036] Powder collection: In zirconia printing, the unbonded ceramic powder in the working chamber after one-time printing, the ceramic powder in the equipment sand storage hopper, and the ceramic powder in the sand spreading device are collected as the same type of powder and concentrated in a bucket for storage.

[0037] Microwave drying: Add the collected zirconia powder to the microwave drying working chamber. The depth of the powder is 250 mm, the microwave power is 9.6 kW, and microwave heating is carried out for 30 cycles. Each cycle includes 3 minutes of microwave heating + 2 minutes of pause.

[0038] Multi-stage screening: Use 180-mesh and 300-mesh sieves to perform secondary screening on the dried zirconia powder, and collect the powder between 180 and 300 meshes for printing use.

[0039] Sealed storage: To prevent the powder from absorbing moisture, place the powder in a container for sealed storage.

[0040] Comparative Example 2

[0041] Set the indicators of new zirconia powder as the comparative example.

[0042] To verify whether the recycled zirconia obtained by the above method meets the usage requirements, the angle of repose and bulk density of the recycled powder were detected. At the same time, the recycled powder was used for printing and the density and dimensional accuracy of the samples were measured. As can be seen from Table 2 below, the parameters such as the angle of repose and bulk density of the recycled zirconia powder meet the internal control requirements, and the density and dimensional accuracy of the printed samples also meet the requirements.

[0043] Table 2 Related parameters of Example 2 and Comparative Example 2

[0044]

[0045] 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. The scope of the present invention is defined by the appended claims and their equivalents.

[0046] The above specific embodiments are detailed descriptions of the present invention. It cannot be determined that the specific embodiments of the present invention are only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions and substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. An efficient recovery method for ceramic powder in binder jet 3D printing, characterized in that, The method includes the following steps: Step 1: Collect the unbonded ceramic powder as the powder to be recycled; Step 2: Microwave dry the ceramic powder to be recycled; Step 3: Multistage screen and store the dried ceramic powder in a sealed manner to obtain the recycled ceramic powder.

2. The efficient recovery method of ceramic powder for binder jetting 3D printing according to claim 1, characterized in that The ceramic powder is one or several of alumina, zirconia, quartz, ceramsite sand, yttrium oxide, silicon carbide, and silicon nitride.

3. The high-efficiency recovery method for ceramic powder in binder jet 3D printing according to claim 1, wherein, In Step 2, the microwave power is 6 - 10 kW, and the microwave heating time is 40 - 90 minutes.

4. The high-efficiency recovery method for ceramic powder in binder jetting 3D printing according to claim 1, characterized in that In Step 2, the depth of the ceramic powder for microwave drying is 200 - 250 mm.

5. The high-efficiency recovery method of ceramic powder for binder jet 3D printing according to claim 1, characterized in that, In Step 3, the specific method of multistage screening includes adding the dried powder into a two-stage vibrating screen, and the two-stage vibrating screen includes a coarse screen and a fine screen, removing the large particles on the coarse screen and the fine powder under the fine screen.

6. The high-efficiency recovery method of ceramic powder for binder jetting 3D printing according to claim 5, characterized in that The mesh number of the coarse screen is 70 - 180 meshes, and the mesh number of the fine screen is 200 - 325 meshes.

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