JP2004305717A - Powder sintering kitchen knife - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder sintering kitchen knife improving the cutting performance by a light load and improving rust prevention performance and sanitation maintenance performance on the surface of the blade material. <P>SOLUTION: This kitchen knife is characterized by including a powder sintering blade material manufactured using powder metallurgy and setting the whole surface roughness, excluding the edge attachment part in the blade foremost part of a blade material formed into a desired shaped, to Ra 0.1 or less by a loose grain polishing method. The blade part is characterized by being formed of titanium alloy powders or ceramic powders. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a powdered kitchen knife manufactured by using powder metallurgy technology, and more particularly to a kitchen knife for various kinds of cooking such as food cutting, and a work knife for various industrial uses such as rubber sponge, paper, and fiber.

  As kitchen knives for cooking vegetables, fruits, meat, fish, etc., use not only carbon steel or stainless steel cooking knives, but also powder metallurgy using titanium alloy powder or zirconia ceramic powder. Kitchen knives are frequently used. Of these, kitchen knives made of titanium alloy powder or ceramic powder are excellent in rust resistance, lightweight, and harder than steel or stainless steel knives, so that the blades can be sharpened, and cooking and working Suitable for kitchen knives.

  It has been considered that the cutting performance of the conventional powder sintered kitchen knife is substantially caused by the sharpness of the blade tip, the shape of the blade, the blade angle, and the blade strength.

Patent Literature 1 discloses a method of compressing a kitchen knife material indicated by afgde by powder compression molding, as shown in a cross-sectional enlarged view of a conventional powder sintered kitchen knife of FIG. 1 attached to the present specification. After being formed as a plate-shaped sintered body by sintering, the sintered body is ground to form a bc ground surface of the cutting edge of the cutting edge, and the dc surface is a refracted sintered surface. A knife with a sharper blade is provided by using the stronger intergranular bond on the refraction sintered surface by leaving it as it is without grinding.
JP-A-11-099287

  However, even with such a blade, the cutting ability is limited due to the frictional force between the object to be cut and the surface of the kitchen knife, causing microcracks during grinding of the blade surface, and food juice adhering to the surface of the blade material. And other sanitation problems.

  An object of the present invention is to provide a powder that can be cut by a lighter load, does not cause microcracks during grinding of the blade surface, and does not cause sanitary problems such as food juice adhering to the surface of the blade material. It is to provide a sintered kitchen knife.

  The inventor of the present invention will be able to influence the cutting ability of the kitchen knife by selecting the magnitude of the coefficient of friction on both sides of the plate-shaped blade such as a kitchen knife and the selection of the blade material surface processing method. Focusing on this point, the surface roughness of the entire kitchen knife is removed by a free abrasive grain polishing method, such as barrel polishing, buff polishing, etc., except for the blade tip with a width of usually 1 mm or less formed at the tip of the plate-shaped kitchen knife material. It was confirmed that the problem could be solved by reducing the roughness of the sintered surface and the roughness of the ground surface.

  That is, the present invention intends to provide a powder-sintered kitchen knife with improved cutting performance under lighter load, improved rust prevention performance, and improved hygiene maintenance performance of the blade material surface. This is a kitchen knife containing a powder sintered blade material manufactured using the technology, and the entire surface of the blade material having a desired shape except the cutting edge of the cutting edge at the cutting edge is formed by a free abrasive polishing method. Is set to Ra 0.1 or less.

  According to the powder sintered knife of the present invention, by reducing the coefficient of friction generated on both side surfaces of the blade material, in the case of a kitchen knife for food cooking, when cutting the same food material, a lighter load is applied. Allows cutting.

  In addition, by improving the smoothness of the surfaces of both sides of the knife blade, it is possible to prevent the generation of microcracks and rusting, and to prevent the attachment of food and food juice to the knife blade surface Thus, a sanitary cooking blade can be obtained. Furthermore, when using for cutting knives such as work knives, such as fibers, paper, rubber, and plastics that have almost no water content, cut with a lighter load due to the low friction coefficient effect due to the smooth surface. It is possible to obtain a blade material that can be used.

A powder sintered kitchen knife according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 2 is a plan view of a powdered kitchen knife of one embodiment according to the present invention, and FIG. 3 is an enlarged cross-sectional view of the kitchen knife. FIG. 4 is an enlarged cross-sectional view of a powdered kitchen knife having a cross section of still another embodiment.

  From FIG. 2, the kitchen knife is composed of a handle 1 and a blade 2 attached thereto. The blade 2 is a plane portion 3, followed by an oblique grinding portion 4 ground into an inclined shape and the cutting edge of the blade 1. It consists of a blade tip attaching part 5 formed in the part.

  In forming the blade material 2, first, a titanium alloy powder or a ceramic powder is filled in a mold formed in a desired shape, pressed and molded at a required pressure, and then sintered to obtain a desired planar shape. Is obtained. The material is cut to the desired thickness by surface grinding, if necessary, and then the inclined shape is ground to make the cutting edge thinner, leaving the cutting edge of the cutting material uncut. Get 2.

  Next, the entire surface roughness of the cutting edge 2 of the cutting edge 2, that is, the entire surface of the cutting edge 2 excluding the cutting edge portion 5 is smoothed to a Ra of 0.1 or less by barrel polishing, buff polishing, or the like. Finish on a smooth surface. Next, the last remaining blade material, which is at the forefront of the blade material, is subjected to a blade edge forming finish polishing to obtain a finished product.

  The feature of forming a fine surface roughness surface by loosened abrasive grains such as barrel and buff polishing is that unlike the fixed abrasive grinding method such as grinding stone grinding, it is a polishing method by rotating and sliding the abrasive grains. When used for polishing, there is an advantage that the surface of the sintered structure can be made smooth without breaking and grinding the sintered bonding particles.

  On the other hand, the fact that the barrel and buffing, which are the requirements of the present invention, are not applied to the blade tip attaching portion 5 which is the ground surface of the blade end, requires the presence of a friction coefficient at the blade end in order to improve the cutting ability. Therefore, if the surface roughness of this portion is reduced, an adverse effect occurs. Therefore, except for the blade end grinding part, barrel and buff polishing methods are used to reduce the roughness of the entire side surface of the kitchen knife at other parts, and the surface roughness is set to 0.1 or less to reduce the roughness at the time of cutting. The frictional stress on both sides of the kitchen knife can be reduced to increase the cutting ability under the same pressing force.

  In order to improve the workability of conventional blade knives in the manufacture of kitchen knives, use a grinding wheel with all abrasive grains fixed and rotate it at high speed to grind the workpiece. To form a plane thickness or to perform inclined shape grinding. However, unlike fused-rolled metal bodies such as general carbon steel-based blades, powdered sintered blades provide high hardness and rust-resistant performance that carbon steel cannot obtain, while binding sintered powder particles. Since it is a structured body, it generally has one side weak in impact resistance. Therefore, when grinding a high hardness sintered body such as a thin plate-shaped blade material, if the fixed grinding wheel particle grinding method is used, the fixed grinding wheel particles forcibly act on the sintered bonded particles at the knife surface grinding part As a result, it is a known phenomenon that micro-clear cracks (microcracks) occur at the boundaries of the respective sintered particles. On the other hand, in the barrel and buff polishing methods that are the free abrasive polishing methods, a feature of the non-forced polishing method is that a micro crack is less likely to occur.

  The free abrasive polishing method using rotationally moving abrasive grains is intended as a polishing method for maintaining the surface texture strength and obtaining a smooth textured surface with the intention of soft and minute abrasion of the sintered bonded structure. When applied to a material, it exerts a smoothness effect on the fine roughness surface, and the high hardness and rust-proof performance of the blade material can maintain its surface state for a long time, mainly due to a decrease in surface friction coefficient It is possible to maintain the light-load cutting ability and to improve the hygiene effect due to the absence of the juice of the food to be cut due to the smoothness of the surface over a long period of time.

  Conventionally, most carbon steels (including SUS) have been used for blade materials. In the case of kitchen knives that rust even in seawater, such as carbon steel-based blades, for example, even if the micro surface roughness processing as in the present invention is performed, they will easily rust in actual use, and the fine roughness of the surface is destroyed, resulting in a smooth surface. Long-term maintenance of the surface is completely impossible.

The inventor carried out the following experiment in order to compare the performance of the powder sintered kitchen knife according to the present invention with that of the conventional powder sintered kitchen knife.
The cutting ability test of the blade material is a paper cutting ability test method in which a blade is applied to the laminated paper, and the blade is moved under a constant pressing load for a certain distance to move the blade to measure the number of cut papers. . For example, if the side surface roughness of each plate-shaped knife blade is individually changed for a comparison test of the cutting knives of two types, the magnitude of the surface roughness will cause the magnitude of the friction coefficient to increase, and the same load will be applied. It is proved by experiments that the cutting ability changes greatly under the conditions, and the smoothness of the surface on both sides of the kitchen knife changes greatly depending on the choice of the construction method to reduce the surface roughness, and the cutting ability test It can be confirmed that the result has a large effect.

  FIG. 5 is an enlarged photograph (500-fold magnification) of the surface of a conventional powder-sintered kitchen knife, which was taken by compressing and sintering ceramic powder to produce a kitchen knife (hereinafter referred to as a comparative example) in a non-processed state. FIG. 6 is an enlarged surface photograph (500-fold magnification) of a powder sintered kitchen knife (hereinafter, referred to as an example) according to the present invention, and the surface roughness Ra is 0.1927, the dynamic friction coefficient is 0.117. A photograph of the surface of the kitchen knife surface taken with a buff was taken (surface roughness Ra = 0.0626, dynamic friction coefficient 0.100).

  The inventor tried the cutting ability of the blade material of the comparative example and the example manufactured as described above, and in the test, fixed the blade material and superimposed a paper equivalent to 7.5 mm wide newsprint to 750 g. The number of cuts was measured with one reciprocation as the number of cuts when reciprocating about 15 mm while applying a load, and the results are shown in Table 1 below (Gifu Pref. This is the result of a laboratory test report.)

  As can be seen from the experimental results, the frictional force on both sides of the sintered powder knives according to the present invention was reduced in size, so that even if the powder was cut with a light force, the frictional force exhibited excellent performance. We were able to confirm from the results.

It is a sectional enlarged view of the conventional powder sintering knife. 1 is a plan view of a powdered kitchen knife according to an embodiment of the present invention. FIG. 3 is an enlarged cross-sectional view of the kitchen knife of FIG. 2. FIG. 4 is an enlarged cross-sectional view of a powdered kitchen knife having a cross section of another embodiment. It is a surface enlarged photograph of the conventional powder sintering knife. 3 is an enlarged photograph of the surface of a powdered kitchen knife according to the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Handle part 2 Blade material 3 Plane part 4 Bevel grinding part 5 Blade tip attached part

Claims (2)

A kitchen knife including a powder sintered blade material manufactured using powder metallurgy technology,
A powder-sintered kitchen knife, characterized in that the entire surface of a blade material having a desired shape, except for the tip end portion of the blade portion, has a total surface roughness of Ra 0.1 or less by a free abrasive polishing method.   The powder knife according to claim 1, wherein the blade is made of a titanium alloy powder or a ceramic powder blade.

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