Method for producing kitchen knife

Abstract

A 3D print fabrication step is performed for fabricating, with a 3D printer 100, the entirety of a kitchen knife 1 having: a blade part 10 which includes a cutting edge part 11 that includes an edge 13 and a spine part 12 that is positioned on the opposite side of the cutting edge part 11 from the edge 13, and in which the thickness of the cutting edge part 11 gradually decreases from the spine part 12 side toward the edge 13; and a handle part 20 which is connected to the blade part 10.

Description

How knives are made

[0001] The present disclosure relates to a method for manufacturing a kitchen knife.

[0002] A kitchen knife has a structure in which a metal blade including a cutting edge is attached to a ferrule and a handle (see, for example, Patent Document 1). Conventionally, kitchen knives are manufactured by laser-processing or pressing a flat metal plate, hardening it in a heat treatment process, and then shaping the blade through various processes such as grinding and polishing, and then welding the ferrule and assembling the handle.

[0003] JP 2023-042088 A

[0004] However, conventional knife manufacturing methods require many steps to form the blade, as well as many other manufacturing processes, such as connecting the ferrule to the blade and assembling the handle. Furthermore, because the blade is formed from a metal plate, excess material is generated that is not used for the blade, and a lot of dust is generated during the grinding and polishing process to form the cutting edge.

[0005] An object of the present disclosure is to provide a method for manufacturing a kitchen knife that can simplify the manufacturing process and suppress the generation of excess material and dust.

[0006] In order to achieve the above object, the manufacturing method of the knife of the first invention includes a 3D printing process in which the entire knife (1) having a blade portion (10) including a cutting edge portion (11) including a cutting edge (13) and a back portion (12) located on the opposite side of the cutting edge of the cutting edge, the thickness of the cutting edge portion gradually decreasing from the back portion side toward the cutting edge, and a handle portion (20) connected to the blade portion is shaped using a 3D printer (100).

[0007] In this way, by using a 3D printer to create the entire knife, including the blade and handle with a tapered cutting edge from the beginning, the manufacturing process can be reduced and simplified compared to the conventional method of assembling each part after forming them into the desired shape. Furthermore, there is almost no need to process the blade and handle into the desired shape, which eliminates the excess material generated during this processing and eliminates the need to use more material than necessary, thereby reducing material consumption. Furthermore, by creating the blade so that the cutting edge is tapered from the beginning, it is possible to suppress the generation of dust.

[0008] In the second invention, in the 3D printing process, in addition to the handle portion (21), a handle base (22) that connects the blade portion and the handle portion and gradually increases in dimension from the thickness of the blade portion to the thickness of the handle portion from the blade portion to the handle portion is formed together with the blade portion.

[0009] By using a 3D printer to create a knife, it is possible to create a knife with a structure that has never been seen before, so when forming the blade and handle, it is possible to simultaneously create a structure in which the handle and blade are connected via the base of the handle.By making the base of the handle so that the thickness of the blade gradually increases from the thickness of the thin plate-like blade to the thickness of the handle, it is possible to create a structure that is continuously connected from the blade to the handle.

[0010] In the third invention, in the 3D printing process, a knife is formed by stacking multiple layers in the shape of a knife using a 3D printer, and the layers are stacked from the back to the cutting edge so that the back of the knife faces downward and the cutting edge faces upward.

[0011] The blade gradually becomes thinner from the back to the cutting edge. When forming a knife with this shape, if the thick back is formed first and the thin cutting edge is formed later, it is easier to form than if the thin cutting edge is formed first and the thick back is formed later.

[0012] In the fourth invention, in the 3D printing modeling process, a knife is formed by stacking multiple layers in the shape of a knife using a 3D printer, and the knife is formed so that one of the two surfaces of the blade portion of the knife faces up and the other faces down.

[0013] By determining the top and bottom orientation of the blade in this way, when forming a knife with a multi-layered structure using a 3D printer, the blade can be aligned along the surface direction of the layers, meaning that the cutting direction of the knife can be aligned along the surface direction of each layer. This makes it possible to make the blade stronger.

[0014] In the fifth invention, a sharpening process for sharpening the cutting edge, including the cutting edge, is included after the 3D printing process. Because the tapered blade and handle are all already formed by the 3D printer, a knife with a sharp cutting edge can be completed by proceeding to at least the sharpening process after the 3D printing process, thereby simplifying the manufacturing process.

[0015] In the sixth invention, after the 3D printing process, the following steps are performed: a heat treatment process for hardening the knife; a straightening process for removing distortion from the heat-treated knife; and a sharpening process for sharpening the cutting edge, including the cutting edge, of the knife that has undergone the straightening process. Thus, even if the heat treatment process and the straightening process are performed in addition to the sharpening process, it is possible to omit steps that were previously required, thereby simplifying the manufacturing process. Additionally, even if the knife that has undergone the straightening process is subjected to a shot blasting process to roughen the surface of the cutting edge in a location other than the cutting edge of the blade, as in the seventh invention, it is possible to omit steps that were previously required, thereby simplifying the manufacturing process.

[0016] In the eighth invention, in the 3D printing molding process, a protruding rib (16) is formed on one side of the blade portion, and the knife is molded so that the position on the other side (10b) of the blade portion opposite the one side (10a) of the blade portion, which corresponds to the position where the rib is formed on the one side and the position corresponding to the periphery of the position where the rib is formed, are flush with each other.

[0017] In this way, by using a 3D printer, even when forming a rib on one side of the blade, it is possible to create a shape so that the rib formation position on the other side and the corresponding position around it are flush with each other. Furthermore, because it is possible to create a shape without depressions caused by the formation of the rib, there is no need to perform a grinding process to flatten the other side, which makes it possible to further simplify the manufacturing process.

[0018] In the ninth invention, in the 3D printing process, a three-dimensional structure is formed with a cavity (30) recessed from or penetrating the surface of the knife in at least one of a location on the blade other than the cutting edge of the cutting edge and the handle.

[0019] In this way, a 3D printer can be used to create knives with complex structures, such as three-dimensional structures with cavities. In this case, by providing cavities in the knife, it is possible to reduce the amount of material used in the knife. Furthermore, by providing cavities in a location other than the cutting edge of the blade or in the handle, material can be reduced in areas not used as a blade, eliminating the need to use more material than necessary and allowing the weight of the knife to be appropriately designed.

[0020] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below.

[0021] FIG. 1A is a front view of a kitchen knife according to a first embodiment of the present disclosure. FIG. 1B is a view of FIG. 1A as viewed from above. FIG. 1C is a view of FIG. 1A as viewed from the left side. FIG. 2 is a flowchart showing the manufacturing process of the kitchen knife. FIG. 3 is a view showing the manufacturing of the kitchen knife using a 3D printer. FIG. 4A is an enlarged cross-sectional view of the vicinity of the cutting edge of the cutting edge portion after the 3D printing process. FIG. 4B is an enlarged cross-sectional view of the cutting edge portion of the cutting edge portion after the sharpening process. FIG. 5 is a cross-sectional view of a portion of the cutting edge portion of a kitchen knife according to a second embodiment of the present disclosure.

[0022] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the following, including other embodiments described below, identical or equivalent parts will be denoted by the same reference numerals.

[0023] First Embodiment In this embodiment, a method for manufacturing a knife using a 3D printer will be described. The drawings accompanying this specification show the X-axis, Y-axis, and Z-axis. The length direction of the knife is called the X-axis, the blade width direction perpendicular to the X-axis is called the Y-axis, and the thickness direction of the knife perpendicular to the X-axis and Y-axis is called the Z-axis.

[0024] [Structure of the Knife] First, referring to Figures 1A to 1C, a knife 1 manufactured using a 3D printer will be described. The knife 1 shown in Figures 1A to 1C includes a blade 10 and a handle 20, with the handle 20 connected to the blade 10 in the X-axis direction. The blade 10 and the handle 20 are made of, for example, maraging steel, and are all formed simultaneously as a single part using a 3D printer. The blade 10 and the handle 20 may also be made of other materials, such as stainless steel, other metals such as titanium, ceramics, or resin.

[0025] The blade 10 has a cutting edge 11 and a back 12, and is connected to a handle 20 at the back 12.

[0026] The cutting edge portion 11 is the portion extending from the cutting edge 13 to the sinew 14. The cutting edge portion 11 is thin-plate shaped, and the cross section along the YZ plane from the sinew 14 toward the cutting edge 13 gradually tapers, with one surface 10a and the opposite surface 10b being flat surfaces inclined with respect to the Y-axis direction or curved surfaces whose cross section in a plane parallel to the YZ plane is bulging like a clam. The cutting edge portion 11 is sharp throughout the entire cutting edge 13, from the cutting edge 13a to the middle 13b and jaw 13c.

[0027] The back 12 has a three-dimensional shape from the ridge 14 to the ridge 15, and is a three-dimensional structure that is continuously connected to the handle 20. The dimension of the back 12 in the Y-axis direction gradually increases from the front end of the blade 10 in the X-axis direction to the rear end, specifically from the position between the cutting edge 13a and the middle part 13b of the cutting edge 11 toward the jaw 13c, and at the position where it connects to the handle 20, the dimension of the back 12 in the Y-axis direction matches that of the handle 20.

[0028] The handle 20 includes a handle 21, a handle base 22, and a handle butt 23, and is rod-shaped and located on the opposite side of the knife 1 from the blade 10. The handle 21 is the part that is gripped by the user, and has an easy-to-grip shape, such as a roughly polygonal or elliptical cross-sectional shape with rounded corners. The handle base 22 connects the handle 21 and the blade 10, and is shaped so that its thickness gradually increases from the thickness of the spine 12 of the thin plate-like blade 10 to the thickness of the handle 21 from the blade 10 to the handle 21. Specifically, as shown in FIG. 1B , when the knife 1 is viewed from the ridge 15 side, the handle base 22 has a generally isosceles trapezoidal shape with the tip of the knife 1 as the upper base and the rear end as the lower base. The handle base 22 may have a structure in which the thickness increases linearly from the back 12 to the handle 21, or a structure in which the thickness increases from the back 12 to the handle 21, or a structure in which the thickness increases from a position midway from the back 12 to the handle 21. The handle butt 23 is the rear end of the handle 20.

[0029] Furthermore, a portion of the knife 1 different from the cutting edge 13, preferably a portion different from the cutting edge 11, has a plurality of cavities 30 recessed from or penetrating the surface, forming a three-dimensional structure. Specifically, the entire handle 20, including the back 12, the handle 21, and the butt 22, has a three-dimensional structure with cavities 30, and as shown in FIG. 1C, a cavity 30 is also formed in the butt 23. This three-dimensional structure is, for example, as shown in FIGS. 1A and 1B, a continuous structure in which the back 12, the handle 22, and the handle 21 are connected. In other words, the blade 10 and the handle 20 are configured as an integrated part, and the back 12 and the handle 20 form a seamless, continuous three-dimensional structure all the way to the boundary between the blade 10 and the handle 20. The knife 1 is configured in this manner.

[0030] [Method of Manufacturing the Knife] Next, a method of manufacturing the knife 1 configured as described above will be described with reference to the flowchart shown in Fig. 2. The knife 1 is manufactured by carrying out the manufacturing processes of steps S1 to S7 shown in Fig. 2.

[0031] (a) 3D Printing Process First, in step S1, a 3D printing process is performed in which the knife 1 shown in FIGS. 1A to 1C is formed using a 3D printer. Any type of 3D printer may be used, but the following description will be given taking as an example a case in which the knife 1 is formed by additive manufacturing. FIG. 3 shows a 3D printer 100 used to form the knife 1. The 3D printer 100 is equipped with a printing machine 101 and a control device 102. The printing machine 101 is a device that forms the knife 1 by additive manufacturing. The control device 102 outputs data used to manufacture the knife 1 to the printing machine 101 and controls the printing machine 101 to form the knife 1. The control device 102 is configured by a microcomputer equipped with a CPU, ROM, RAM, I / O, etc., and stores various programs such as slicing software.

[0032] For example, the knife 1 is designed in advance using 3D CAD or the like, and the 3D data of the knife 1 is input into the control device 102. At this time, if the 3D data is 3D CAD data that is not polygon data, it is converted into polygon data by the control device 102. Next, the control device 102 uses slicing software to create slice data that indicates the molding pattern when the knife 1 is sliced ​​into each layer from the polygon data.

[0033] The control device 102 then outputs slice data to the printer 101, and the knife 1 is formed by sequentially stacking the modeling patterns for each layer based on the slice data. While maraging steel is used as the material for the modeling, other metals such as stainless steel and titanium, as well as other materials such as ceramics and resin, may also be used. This allows the blade 10 and handle 20 to be formed simultaneously, the spine 12 to be connected to the handle 21 via the handle base 22, and the knife 1 can be formed in which the blade 10 and handle 20 are integrated as a single component.

[0034] At this time, the order in which the knife 1 is shaped, i.e., from which position the shaping begins, is arbitrary, but it is preferable to shape the knife 1 by stacking each layer from the back 12 toward the cutting edge 13, with the back 12 facing downward and the cutting edge 13 facing upward, as shown in Figure 3.

[0035] The blade 10 gradually becomes thinner from the spine 12 toward the cutting edge 13. When forming the blade 10 and handle 20 using the 3D printer 100, it is easier to form the thick spine 12 first and then form the thin cutting edge 13 later, rather than forming the thin cutting edge 13 first and then forming the thick spine 12 later. Furthermore, it is desirable to make the cutting edge 13 as thin as possible, for example, to about 0.2 mm as shown in FIG. 4A , in order to reduce the amount of processing required during the subsequent sharpening process. However, if the cutting edge 13 is formed last, it is not necessary to consider layering anything on top of the cutting edge 13, making it possible to make the cutting edge 13 even thinner.

[0036] (b) Heat Treatment Step The knife 1 manufactured in the 3D printing manufacturing step is subjected to a heat treatment step for age hardening in step S2. In the heat treatment step, high-temperature heat treatment is performed followed by cooling to room temperature, which promotes the time transformation of the structure of the material that makes up the knife 1 and hardens the knife 1. Furthermore, by cooling and reheating as necessary, it is possible to further impart toughness to the knife 1 that makes the hardness uniform and prevents cracking when bending.

[0037] (c) Straightening Process After the heat treatment process, a straightening process is carried out as step S3. Since the knife 1 has distortion due to volume expansion and contraction, the straightening process involves straightening the distorted parts.

[0038] (d) Shot Blasting Step After the distortion removal step, the shot blasting step is carried out as step S4. In the shot blasting step, glass beads made of fine glass particles are blasted onto the surface of the knife 1 in areas other than the cutting edge 13. This gives the surfaces of the blade 10 and handle 20 a finely roughened surface.

[0039] (e) Marking Process After the shot blasting process, a marking process is carried out as step S5. In the marking process, various markings such as the brand name, the history of materials used, and the date and time of each process are made on a location on the knife 1, such as the back 12. This allows for traceability.

[0040] (f) Sharpening Process After the marking process, the sharpening process is performed as step S6. In this process, the cutting edge 11 of the blade 10 is sharpened. For example, when performing wet sharpening, water is applied to a whetstone (not shown) or the blade 10 to prevent heat generation due to friction. This makes the cutting edge 13 smoother, improving sharpness. The blade 10 formed in the 3D printing process already has a tapered cutting edge 13, as shown in FIG. 4A. Therefore, unlike grinding and polishing a rectangular plate until the tip is sharp, this sharpening process requires only a slight polishing process until the cutting edge 13 is sharp, as shown in FIG. 4B. This also reduces dust generation.

[0041] (g) Packaging Step Finally, in step S7, the packaging step is carried out in which the knives 1 that have passed the predetermined inspection are packed into boxes. This completes the packaging of the knives 1, making them ready for shipment.

[0042] As described above, the knife 1 is formed by performing the 3D printing process using a 3D printer. As a result, the following effects are obtained.

[0043] (1) In the manufacturing method of the knife 1 described in this embodiment, the entire knife 1 is formed using a 3D printer 100. Conventionally, when the blade, handle, and ferrule are separately manufactured and then assembled into the desired shape, each process is required, increasing the number of manufacturing steps. However, by using the 3D printer 100 as in this embodiment, the entire knife 1 having the blade 10 and handle 20 with a tapered cutting edge 13 can be formed from the beginning, thereby reducing the number of manufacturing steps. Furthermore, reducing the number of manufacturing steps also makes it possible to reduce the environmental impact and energy consumption.

[0044] Specifically, in this embodiment, the knife 1 is manufactured by performing the steps S1 to S7 described above. Because the knife 1 can be manufactured simply by performing steps S1 to S7, the knife 1 manufacturing process can be simplified compared to conventional methods. Furthermore, among the steps S1 to S7, some steps can be omitted if the focus is solely on completing the manufacturing of the knife 1, further simplifying the process. For example, the manufacturing of the knife 1 can be completed without performing the marking step S5 or the packaging step S7. Furthermore, if the knife 1 can be molded using the 3D printer 100 to approximate the shape of the final product, the heat treatment, distortion relief, and shot blasting steps S2 to S4 can also be omitted. In other words, because the blade 10 and handle 20, each with a tapered cutting edge 13, have already been formed by the 3D printer 100, the knife 1 can be completed by at least sharpening the cutting edge 13, further simplifying the manufacturing process. Furthermore, even if the heat treatment, distortion relief, and shot blasting processes are performed in addition to the sharpening process, it is possible to omit steps that were previously required, thereby simplifying the manufacturing process.

[0045] For example, in conventional manufacturing methods, a flat metal plate is laser-processed or pressed to form the outer shape of the blade, followed by a heat treatment process and a distortion removal process, followed by an outer peripheral grinding process and a gap grinding process to sharpen the tip of the flat blade. Furthermore, a blade leveling process is carried out to give the cutting edge a smooth, bulging, clam-shaped curve, and a glazing process is carried out to finely grind the entire blade. This is followed by a ferrule welding process to weld the ferrule and polish the welded part, and a final assembly process to attach the handle to the blade with the ferrule welded.

[0046] In contrast, according to the manufacturing method of this embodiment, the knife 1 in which the blade 10 and the handle 20 are connected and the blade tip 13 has a tapered shape from the beginning can be produced using the 3D printer 100. This makes it possible to omit the laser processing or press processing, the outer periphery polishing process, the gap grinding process, the blade leveling process, the glazing process, the ferrule welding process, and the assembly process.

[0047] (2) The 3D printer 100 can be used to create various shapes of the knife 1, and can create blade 10 and handle 20 with tapered cutting edges 13 from the beginning. This eliminates the need to process the blade 10 and handle 20 into the desired shape, eliminating excess material generated during various processes and eliminating the need to use more material than necessary, thereby reducing material consumption. Furthermore, in conventional manufacturing methods, a flat plate is press-processed or laser-processed to form the outer shape of the blade, and then the plate is ground to create the cutting edge. This requires grinding and polishing processes to create a sharp cutting edge, which generates a lot of dust. In contrast, using the 3D printer 100 to create the blade 10 with a tapered cutting edge 13 from the beginning can significantly reduce dust generation.

[0048] (3) By using the 3D printer 100 to form the knife 1, it is possible to form the knife 1 with a structure that has never been seen before, and the knife 1 can be formed from a variety of materials, not just metal, such as ceramics and resin, thereby improving the freedom of knife design.

[0049] For example, when forming the kitchen knife 1 using the 3D printer 100, when forming the blade 10 and the handle 20, it is possible to simultaneously form a structure in which the handle 21 and the blade 10 are connected via the handle base 22. Then, by forming the handle base 22 so that the dimensions gradually increase from the thickness of the thin plate-like blade 10 to the thickness of the handle 21 from the blade 10 to the handle 21, it is possible to form a structure that is continuously connected from the blade 10 to the handle 21.

[0050] It is also possible to form a knife 1 with a complex structure, such as a three-dimensional structure with a cavity 30. In this case, by providing the cavity 30 in the knife 1, it is possible to reduce the amount of material used for the knife 1. If the cavity 30 is formed in a location on the knife 1 other than the cutting edge 13, preferably other than the cutting edge portion 11, such as the back portion 12 or handle portion 20, it is possible to reduce material in the portion not used as a blade, which eliminates the need to use more material than necessary, and allows the weight of the knife 1 to be designed appropriately.

[0051] (4) The blade 10 gradually becomes thinner from the back 12 side to the cutting edge 13 side. When forming a knife 1 having such a shape, if the thick back 12 is formed first and the thin cutting edge 13 is formed later, the formation is easier than if the thin cutting edge 13 is formed first and the thick back 12 is formed later. Furthermore, if the cutting edge 13 is formed last, there is no need to consider layering anything on top of the cutting edge 13, so the thickness of the cutting edge 13 can be made thinner.

[0052] Second Embodiment A second embodiment will be described. This embodiment is similar to the first embodiment except for the shape of the blade 10, and therefore only the differences from the first embodiment will be described.

[0053] 5 shows the knife 1 after the 3D printing process of step S1 described in the first embodiment, cut along a cross section parallel to the YZ plane. As shown in this figure, a protruding rib 16 is formed on one surface 10a of the cutting edge portion 11 of the blade 10. On the other surface 10b, which is opposite the surface 10a on which the rib 16 is formed, a position corresponding to the position of the rib 16 on the one surface 10a and a position corresponding to the periphery of the position of the rib 16 are flush with each other.

[0054] Providing ribs 16 on the first surface 10a of the knife 1 makes it easier for pieces of food cut with the knife 1 to separate from the knife 1, improving the blade release of the knife 1. When manufacturing a knife 1 equipped with such ribs 16 using a 3D printer 100, even if the ribs 16 are formed on the first surface 10a of the blade 10, the position of the ribs 16 on the other surface 10b and the corresponding positions around them can be molded flush. When the ribs 16 are formed by press working or the like, forming the ribs 16 creates a recess on the other surface 10b, necessitating a grinding process to remove a thickness greater than the recess caused by the rib formation in order to flatten the other surface 10b. However, if the ribs 16 are formed from the beginning using the 3D printer 100, a mold can be created without the recess caused by the formation of the ribs 16, further simplifying the manufacturing process.

[0055] (Other Embodiments) The present disclosure is not limited to the above-described embodiments and can be modified as appropriate within the scope of the claims. Furthermore, in each of the above-described embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above-described embodiments, when numerical values ​​such as the number, numerical value, amount, and range of components of the embodiments are mentioned, they are not limited to the specific number unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above-described embodiments, when the shape, positional relationship, etc. of components, etc. are mentioned, they are not limited to the shape, positional relationship, etc. unless specifically stated or limited to a specific shape, positional relationship, etc. in principle.

[0056] For example, in the first embodiment, the knife 1 was formed during the 3D printing process so that the back portion 12 faced downward and the cutting edge 13 faced upward. However, this is just one example, and the knife 1 may be formed in another orientation. For example, the knife 1 may be formed so that one of the two surfaces of the blade portion 10 of the knife 1 faces upward and the other faces downward.

[0057] In this way, by determining the up-down orientation of the blade portion 10 and molding it, when forming the knife 1 with a multi-layer laminated structure using the 3D printer 100, the blade portion 10 can be aligned along the surface direction of the layers, i.e., the cutting direction of the knife 1 can be aligned along the surface direction of each layer. When forming a multi-layer laminated structure using the 3D printer 100, the bonds between each layer are strong, but the blade portion 10 can be made stronger by forming the blade portion 10 so that the same layer has a large area. Therefore, by molding the knife 1 with the 3D printer 100 so that one side of the blade portion 10 faces up and the other faces down, it is possible to make the blade portion 10 stronger.

[0058] Furthermore, in each of the above embodiments, the back portion 12 and the handle portion 20 have a three-dimensional structure by providing multiple cavities 30, but instead of providing multiple cavities 30, they may be formed in a part of the single connected knife 1 that is different from the cutting edge 13.

[0059] Furthermore, in the second embodiment, the case where the rib 16 is formed as a structure for improving blade release is given as an example, but it is also possible to improve blade release by forming a recess or a through hole in a part of the cutting edge portion 11 different from the cutting edge 13. If the 3D printer 100 is used to shape the knife 1, such a recess or through hole can be formed from the beginning, which further simplifies the manufacturing process of the knife 1.

[0060] 1...Knife, 10...Blade, 10a...One side, 10b...Other side, 11...Cutting edge, 12...Back, 13...Edge, 13a...Cutting edge, 13b...Middle of blade, 13c...Jaw, 14...Spine, 15...Spind, 16...Rib, 20...Handle, 21...Handle, 22...Handle base, 23...Handle butt, 30...Cavity, 100...3D printer, 101...Printing machine, 102...Control device

Claims

1. A method for manufacturing a kitchen knife, comprising a 3D printing process in which a 3D printer (100) is used to form the entire kitchen knife (1), the entire kitchen knife having a blade portion (10) including a cutting edge (11) having a cutting edge (13) and a back portion (12) located on the opposite side of the cutting edge of the cutting edge, the thickness of the cutting edge portion gradually decreasing from the back portion side toward the cutting edge, and a handle portion (20) connected to the blade portion.

2. A method for manufacturing a knife as described in claim 1, wherein in the 3D printing process, in addition to a handle portion (21), a handle base (22) that connects the blade portion and the handle portion and gradually increases in dimension from the thickness of the blade portion to the thickness of the handle portion from the blade portion to the handle portion is formed together with the blade portion.

3. A method for manufacturing a knife as described in claim 1, wherein in the 3D printing process, the knife is formed by stacking multiple layers into the shape of the knife using the 3D printer, and the knife is formed by stacking layers from the back of the knife toward the cutting edge so that the back of the knife faces downward and the cutting edge faces upward.

4. A method for manufacturing a knife as described in claim 1, wherein in the 3D printing process, the knife is formed by stacking multiple layers into the shape of the knife using the 3D printer, and the knife is formed so that one of the two surfaces of the blade portion of the knife faces upward and the other faces downward.

5. A method for manufacturing the knife according to claim 1, further comprising a sharpening process for sharpening the cutting edge portion including the cutting edge after the 3D printing process.

6. A method for manufacturing the knife described in claim 1, which includes, after the 3D printing process, a heat treatment process for hardening the knife, a distortion relief process for removing distortions from the knife that has undergone the heat treatment process, and a blade sharpening process for sharpening the cutting edge portion including the cutting edge of the knife that has undergone the distortion relief process.

7. A method for manufacturing the knife as described in claim 1, comprising, after the 3D printing modeling process, a heat treatment process for hardening the knife, a distortion relief process for removing distortions from the knife that has been heat treated, a shot blasting process for roughening the surface of the cutting edge portion of the blade at locations other than the cutting edge of the knife that has been subjected to the distortion relief process, and a sharpening process for sharpening the cutting edge portion including the cutting edge of the knife that has been subjected to the shot blasting process.

8. A method for manufacturing a knife as described in any one of claims 1 to 7, wherein in the 3D printing process, a protruding rib (16) is formed on one side of the blade portion, and the knife is shaped so that a position on the other side (10b) opposite to the one side (10a) of the blade portion corresponding to the position where the rib is formed on the one side and a position corresponding to the periphery of the position where the rib is formed are flush with each other.

9. A method for manufacturing a knife as described in any one of claims 1 to 7, wherein in the 3D printing process, a three-dimensional structure is formed having a cavity (30) formed by a recessed structure or a penetrating structure in the surface of the knife in at least one of a location of the cutting edge portion of the blade portion different from the cutting edge and the handle portion.

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