A method for preparing a gradient structure kitchen knife by using 3D printing

Abstract

This invention discloses a method for fabricating a gradient-structured kitchen knife using 3D printing, belonging to the field of additive manufacturing technology. The method includes: S1, mechanically alloying 5Cr15MoVCu powder and 430 powder for different durations using GCr steel balls with a diameter of 10mm-12mm, a ball-to-powder ratio of 10:1-12:1, a distance of 30cm-45cm from the grinding jar to the rotation center, and a rotation speed of 300rpm-400rpm, obtaining three nanoparticles with different grain sizes; S2, 3D printing the three nanoparticles with different grain sizes prepared above into a kitchen knife with coarse grains on the outer layer and fine grains on the inner layer, obtaining a gradient-structured kitchen knife. The kitchen knife prepared by this method has ultrafine grains, good toughness, high hardness, excellent corrosion resistance, and antibacterial properties.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology and relates to a method for preparing a gradient structure blade kitchen knife using 3D printing. Background Technology

[0002] 3D printing, controlled by a computer based on 3D CAD data, builds solid parts layer by layer using materials without the need for tools, fixtures, or multiple machining processes. This technology can be used to create two-dimensional thin-layer structures. The raw materials used in 3D printing directly affect the performance of the final product. Currently, commercially available 3D printing metal powders are mainly pre-alloyed powders, which are prepared by melting multiple elements in a set ratio and then using methods such as atomization or rotating electrode methods to create spherical or near-spherical powders. However, these powders typically have relatively large grain sizes, generally above 15μm. Parts printed with these powders are usually large, making it difficult to achieve ultrafine grain structures and thus hindering the improvement of overall product performance.

[0003] On the other hand, the steel used in existing kitchen knives is usually produced by casting and then forging, resulting in coarse grains. Its toughness, hardness, and corrosion resistance are far inferior to those of powder metallurgy steel. As a result, the sharpness and durability of the finished knife are not ideal, and it remains in the low to mid-range compared to foreign kitchen knives. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a method for preparing gradient-structured kitchen knives using 3D printing. The aim is to combine powder metallurgy with 3D printing technology to prepare 5Cr15MoVCu and 430 nanometer powders with different grain sizes. Then, using Selective Laser Melting (SLM) technology, kitchen knives with gradient-structured blades are directly synthesized in situ from the powders. Kitchen knives produced by this method have ultrafine grains, good toughness, high hardness, excellent corrosion resistance, and antibacterial properties.

[0005] To achieve the above objectives, the present invention provides a method for 3D printing to prepare a kitchen knife with a gradient structure blade, characterized by comprising the following steps:

[0006] S1 mechanically alloyed commercially available 5Cr15MoVCu powder and 430 powder for different durations. The ball milling media used were GCr steel balls with a diameter of 10mm to 12mm, a ball-to-powder ratio of 10:1 to 12:1, a distance of 30cm to 45cm between the ball milling jar and the center of rotation, a rotation speed of 300rpm to 400rpm, and ball milling times of 20h, 40h, and 60h, to obtain three nanopowders with different grain sizes.

[0007] S2 uses three different grain sizes of powder prepared by the above method to 3D print kitchen knives in the order of coarse grains on the outer layer and fine grains on the inner layer, to obtain a gradient structure kitchen knife. The prepared kitchen knife has ultra-fine grains with a grain size of 50-150nm, good toughness, high hardness, excellent corrosion resistance, and antibacterial properties.

[0008] A method for 3D printing to prepare a kitchen knife with a gradient-structured blade, characterized by the following steps:

[0009] S3 places powders of three different grain sizes into the hopper of the laser selective melting and forming equipment. The parameters of the laser selective melting and forming equipment are: laser power 200W~300W, scanning speed 100mm / s~110mm / s, scanning spacing 0.1mm~0.15mm, and powder layer thickness 60μm~70μm.

[0010] S4 melts the powder in the slicing area using a laser beam. After the powder that has been ball-milled for 60 hours solidifies, one layer is formed. The working cylinder is lowered by one slice thickness, and powder that has been ball-milled for 40 hours is laid on top. The powder in the slicing area is melted again using a laser beam. After the powder solidifies, the working cylinder is lowered by one slice thickness, and powder that has been ball-milled for 20 hours is laid on top. The above steps are repeated until the entire kitchen knife is formed.

[0011] In the above invention concept, the ball milling process enables 5Cr15MoVCu powder and 430 powder to have ultrafine crystalline structures with different grain sizes, laying the foundation for 3D printing gradient structure materials.

[0012] Furthermore, the original commercially available 5Cr15MoVCu powder and 430 powder have a particle size of 50μm to 150μm.

[0013] Overall, compared with traditional forming processes, this invention innovatively combines powder metallurgy with 3D printing technology, proposing a method for preparing gradient-structured kitchen knives. Specifically, this is reflected in the following aspects:

[0014] (1) The ball milling process results in 5Cr15MoVCu powder and 430 powder having different nanocrystal sizes. In contrast, powders prepared by traditional atomization methods generally have larger grain sizes, typically above 40 μm, and cannot have nanoscale structures or form large size gradients.

[0015] (2) The SLM technology is used to make the gradient structure powder react in situ. The laser beam has a high energy density and can achieve rapid scanning (up to 10m / s). It provides rapid solidification conditions for the micro-melt pool of powder material (diameter of about 10μm to 50μm). The high cooling rate can effectively suppress the growth of grains during the forming process, so that the kitchen knife maintains the nanocrystalline structure, which is conducive to the kitchen knife having excellent comprehensive service performance.

[0016] (3) This kitchen knife has additional antibacterial properties because the Cu ions in its material have a bactericidal function. Traditional kitchen knives do not have antibacterial properties. Attached Figure Description

[0017] Figure 1 The layered martensite structure observed under a transmission electron microscope is that of the kitchen knife prepared in Example 1. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0019] In this embodiment of the invention, the blade is prepared into a kitchen knife through processes such as grinding and sharpening, which are conventional practices in the field and are not the focus of this invention, so they will not be described in detail here. Example

[0020] S1 mechanically alloyed commercially available 5Cr15MoVCu powder and 430 powder with particle sizes of 50μm to 100μm for different times. The ball milling media used were GCr steel balls with a diameter of 10mm, a ball-to-material ratio of 10:1, a distance of 30cm between the ball milling jar and the rotation center, a rotation speed of 300rpm, and ball milling times of 20h, 40h, and 60h, to obtain three kinds of nanoparticles with different grain sizes.

[0021] S2 uses powders with three different grain sizes prepared by the above method, arranged in the order of coarse grains on the outer layer and fine grains on the inner layer, to 3D print a kitchen knife. The method for 3D printing a kitchen knife with a gradient blade structure includes the following steps:

[0022] S3 places powders of three different grain sizes into the hopper of the laser selective melting and forming equipment. The parameters of the laser selective melting and forming equipment are: laser power 200W, scanning speed 100mm / s, scanning spacing 0.1mm, and powder layer thickness 60μm.

[0023] S4 uses a laser beam to melt the powder within the slicing area. After the powder, milled for 60 hours, solidifies, one layer is formed. The working cylinder is lowered by one slice thickness, and powder milled for 40 hours is laid on top. The powder within the slicing area is then melted again using a laser beam. After the powder solidifies, the working cylinder is lowered by one slice thickness, and powder milled for 20 hours is laid on top. This process is repeated until the entire kitchen knife is formed. A gradient-structured blade kitchen knife is obtained. The prepared kitchen knife has ultrafine grains with a grain size of 50 nm, good toughness, high hardness, and excellent corrosion resistance. Due to the presence of Cu ions, it also has antibacterial properties.

[0024] Figure 1 In this embodiment of the invention, the prepared kitchen knife exhibits a layered martensitic structure observed under a transmission electron microscope, with a grain size of approximately 50 nm. Example

[0025] S1 mechanically alloyed 5Cr15MoVCu powder and 430 powder with particle sizes of 70μm to 150μm for different times. The ball milling media used was GCr steel balls with a diameter of 11mm, the ball-to-material ratio was 12:1, the distance between the ball milling jar and the rotation center was 30cm, the rotation speed was 400rpm, and the ball milling time was 20h, 40h, and 60h, to obtain three kinds of nano powders with different grain sizes.

[0026] S2 uses powders with three different grain sizes prepared by the above method, arranged in the order of coarse grains on the outer layer and fine grains on the inner layer, to 3D print a kitchen knife. The method for 3D printing a kitchen knife with a gradient blade structure includes the following steps:

[0027] S3 places powders of three different grain sizes into the hopper of the laser selective melting and forming equipment. The parameters of the laser selective melting and forming equipment are: laser power 300W, scanning speed 110mm / s, scanning spacing 0.15mm, and powder layer thickness 70μm.

[0028] S4 uses a laser beam to melt the powder within the slicing area. After the powder, milled for 60 hours, solidifies, one layer is formed. The working cylinder is lowered by one slice thickness, and powder milled for 40 hours is laid on top. The powder within the slicing area is then melted again using a laser beam. After the powder solidifies, the working cylinder is lowered by one slice thickness, and powder milled for 20 hours is laid on top. This process is repeated until the entire kitchen knife is formed. The resulting gradient-structured blade kitchen knife has ultrafine grains with a grain size of 100 nm, exhibiting good toughness, high hardness, excellent corrosion resistance, and antibacterial properties. Example

[0029] S1 mechanically alloyed 5Cr15MoVCu powder and 430 powder with particle sizes of 70μm to 150μm for different times. The ball milling media used was GCr steel balls with a diameter of 10mm, the ball-to-material ratio was 11:1, the distance between the ball milling jar and the rotation center was 30cm, the rotation speed was 350rpm, and the ball milling time was 20h, 40h, and 60h, to obtain three kinds of nano powders with different grain sizes.

[0030] S2 uses powders with three different grain sizes prepared by the above method, arranged in the order of coarse grains on the outer layer and fine grains on the inner layer, to 3D print a kitchen knife. The method for 3D printing a kitchen knife with a gradient blade structure includes the following steps:

[0031] S3 places powders of three different grain sizes into the hopper of the laser selective melting forming equipment. The parameters of the laser selective melting forming are: laser power 250W, scanning speed 105mm / s, scanning spacing 0.12mm, and powder layer thickness 65μm.

[0032] S4 uses a laser beam to melt the powder within the slicing area. After the powder, milled for 60 hours, solidifies, one layer is formed. The working cylinder is lowered by one slice thickness, and powder milled for 40 hours is laid on top. The powder within the slicing area is then melted again using a laser beam. After the powder solidifies, the working cylinder is lowered by one slice thickness, and powder milled for 20 hours is laid on top. This process is repeated until the entire kitchen knife is formed. The resulting gradient-structured blade kitchen knife has ultrafine grains with a grain size of 120 nm, exhibiting good toughness, high hardness, excellent corrosion resistance, and antibacterial properties. Example

[0033] S1 mechanically alloyed 5Cr15MoVCu powder and 430 powder with particle sizes of 50μm to 120μm for different times. The ball milling media used was GCr steel balls with a diameter of 11mm, the ball-to-material ratio was 10:1, the distance between the ball milling jar and the rotation center was 30cm, the rotation speed was 380rpm, and the ball milling time was 20h, 40h, and 60h, to obtain three kinds of nano powders with different grain sizes.

[0034] S2 uses powders with three different grain sizes prepared by the above method, arranged in the order of coarse grains on the outer layer and fine grains on the inner layer, to 3D print a kitchen knife. The method for 3D printing a kitchen knife with a gradient blade structure includes the following steps:

[0035] S3 places powders of three different grain sizes into the hopper of the laser selective melting forming equipment. The parameters of the laser selective melting forming are: laser power 220W, scanning speed 100mm / s, scanning spacing 0.11mm, and powder layer thickness 68μm.

[0036] S4 uses a laser beam to melt the powder within the slicing area. After the powder, milled for 60 hours, solidifies, one layer is formed. The working cylinder is lowered by one slice thickness, and powder milled for 40 hours is laid on top. The powder within the slicing area is then melted again using a laser beam. After the powder solidifies, the working cylinder is lowered by one slice thickness, and powder milled for 20 hours is laid on top. This process is repeated until the entire kitchen knife is formed. The resulting kitchen knife has a gradient blade structure. The prepared kitchen knife has ultrafine grains with a grain size of 90 nm, good toughness, high hardness, excellent corrosion resistance, and antibacterial properties.

[0037] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for fabricating a gradient-structured kitchen knife using 3D printing, characterized in that, To address the current problem of kitchen knives not being able to simultaneously possess both toughness and strength, the following steps are included: S1. 5Cr15MoVCu powder and 430 powder were subjected to mechanical alloying ball milling for different times. The particle size of the 5Cr15MoVCu powder and 430 powder was 50μm to 150μm. The ball milling media used were GCr steel balls with a diameter of 10mm to 12mm. The ball-to-powder ratio was 10:1 to 12:

1. The distance between the ball mill jar and the rotation center was 30cm to 45cm. The rotation speed was 300rpm to 400rpm. The ball milling time was 20h, 40h, and 60h, respectively, to obtain three kinds of nanopowders with different grain sizes. S2 uses three powders with different grain sizes prepared by the above method to 3D print and obtain a gradient structure kitchen knife. The prepared kitchen knife has ultrafine grains with a grain size of 50-150nm. S2 includes the following specific steps: Three types of powder with different grain sizes were placed in the hopper of a laser selective melting and forming equipment. The parameters of the laser selective melting and forming equipment were: laser power 200W~300W, scanning speed 100mm / s~110mm / s, scanning spacing 0.1mm~0.15mm, and powder layer thickness 60μm~70μm. Powder milled for 60 hours is laid out, and the powder in the slicing area is melted by a laser beam. After the powder milled for 60 hours solidifies, one layer is formed, and the working cylinder is lowered by one slice thickness. Powder milled for 40 hours is laid out, and the powder in the slicing area is melted by a laser beam. After the powder milled for 40 hours solidifies, the working cylinder is lowered by one slice thickness. Powder milled for 20 hours is laid out, and the powder in the slicing area is melted by a laser beam. After the powder milled for 20 hours solidifies, the working cylinder is lowered by one slice thickness. The above steps are repeated until the entire kitchen knife is formed.

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