RU2225787C2 - Razor blade and method for making it - Google Patents

Abstract

FIELD: processes and apparatuses for making cutting devices, namely for making blades designed for removing hairs from human skin. SUBSTANCE: blade is made of rigid monocrystalline material and it has n working zones with wedge-shaped cutting edges arranged in different mutually parallel areas one over another. Each successive working zone has thickness increased by value h = d/n, where d - thickness of substrate, n = 2, 3,.. . Edge of each area is shifted relative to edge of previous area to one side. Method for making blade comprises steps of forming substrate having sharpened wedge- shaped cutting edges and made of rigid monocrystalline material; forming n cutting edges on back side of substrate by anisotropic etching in crystallographic planes along the whole thickness of substrate in specially formed windows; then forming by isotropic etching through windows arranged on upper surface of substrate over each working zone with cutting edge, except last one, working areas with stepwise increased thickness in such a way that increase of thickness of each subsequent area corresponds to value h = d/n, where d - thickness of substrate, n = 2, 3... . EFFECT: increased useful life period of blades, lowered labor consumption for making them due to use of standard manufacturing procedures, enhanced comfortability of using blades. 2 cl, 8 dwg

Description

The invention relates to techniques and technology for cutting tools, namely, to the design and method of manufacturing a razor designed to remove hair from human skin.

A known design of the razor blade [1], which is a steel substrate with a sharp cutting edge. The disadvantage of this design is that during operation, oxidation of the metal and, as a consequence, blunting of the cutting edge occurs. In addition, for the manufacture of a razor with two or more cutting edges, two or more separate blades and additional structural elements of the blade holder cartridge are required, since each blade has only one cutting edge.

A known method of manufacturing a razor blade [2], in which a sheet with at least one hole is made from sheet material and the edge of the hole is sharpened until an annular cutting edge is formed with a point. After edge sharpening, an annular edge is mechanically displaced immediately adjacent to the tip until the latter protrudes in the range of 0.01-0.1 mm to form a shaving angle of 15-35 °. The disadvantage of this method is that for the manufacture of a blade by this method, several mechanical operations are required, including cutting the necessary form of the device, sharpening, extruding the cutting edge with a special punch. In addition, the blade obtained by this method provides high-quality shaving of only very short hair (bristles), since the hair must be cut into the hole with a cutting edge before shaving.

The closest technical solution is a razor blade [3], containing a steel substrate with a wedge-shaped cutting edge, on which, to increase hardness and prevent its oxidation, an intermediate layer is applied selected from the group consisting of molybdenum, niobium, tantalum, vanadium and their alloys, including niobium molybdenum alloy, and a layer of diamond-like carbon material.

The disadvantage of this design is the need for the introduction of additional elements to increase the life of the blade. In addition, for the manufacture of razors with two or more cutting edges, respectively, two or more separate blades and additional structural elements of the cartridge holder blades are required, since each blade has only one cutting edge.

The closest in technical essence and the achieved result is a method of manufacturing the above construction, in which form a substrate with a wedge-shaped pointed edge, put on it an intermediate and additional layer. In this case, the material of the intermediate layer is selected from the group comprising molybdenum, niobium, tantalum, vanadium and their alloys, including niobium-molybdenum alloy, and diamond or diamond-like carbon material is chosen as an additional layer [3].

The disadvantage of this method is the necessity of applying intermediate and additional layers to the blade, as well as the inability to obtain blades with several cutting edges in this way.

The technical result, the achievement of which the present invention is directed, is to increase the service life and the possibility of obtaining several cutting edges on a single substrate, which will simplify the design of the blade holder.

To achieve the specified technical result in a known razor blade containing a substrate with a wedge-shaped cutting edge, the substrate is made of solid single-crystal material and contains n working areas, each of them has a wedge-shaped cutting edge. Each of the cutting edges is located in different planes one above the other, with each subsequent working area increasing in thickness by Δh = d / n, where d is the thickness of the substrate. The number of cutting edges n may be 2, 3, etc. In addition, each subsequent edge is parallelly shifted relative to the previous one in the horizontal direction in one direction.

To achieve the specified technical result in the known method, which consists in forming a substrate with pointed wedge-shaped cutting edges, the substrate is formed from a solid single-crystal material on which by anisotropic (selective) etching along crystallographic planes through the entire thickness of the substrate d in specially formed n windows on its back side receive n cutting edges in them. In this case, the cutting edges are located on the same plane and parallel to each other. Then, by the method of isotropic (non-selective) etching, through the windows located above the upper surface with each cutting edge, except the last one, work areas stepwise increasing in thickness are formed, and the increase in thickness of each subsequent working area corresponds to Δh = d / n, where d is the thickness substrates, and n = 2, 3, etc.

Figure 1-5 shows an illustration of the steps of manufacturing a blade for definiteness with two cutting edges (n = 2) of the proposed method. Figure 6 shows a top view of the resulting thus obtained design of the blade. Similarly, a design with three cutting edges can be made, represented by a sectional view of FIG. 7 and a top view of FIG. 8, or with a different number n.

As the initial substrate is selected, for example, a silicon wafer 1 with an orientation of (100) and a thickness d - Figure 1. A protective mask 2 and 3 is formed on both sides of the wafer by galvanic growth of ~ 5 μm thick copper layers with two etching windows 4 on the bottom side of the substrate and one window 5 on its upper side - Figure 2. In two windows 4, anisotropic (selective) etching of silicon through the entire thickness of the substrate in an alkali solution of 45% KOH at a temperature of 95 ° C is performed on the bottom side of the substrate — FIG. 3. Selective etching provides the inclination of the side walls in the window 6 in accordance with the crystallographic orientation of the plate with an acute angle of 54 °. After etching, two cutting edges 7 and 8 are formed in these windows, located in the same plane on the upper side of the substrate and parallel to each other. Through the window 5 on the upper side of the substrate, located above the region with the first cutting edge 7, isotropic (non-selective) silicon etching is performed, for example, by plasma etching to a depth d / 2 - FIG. 4. In this case, the first cutting edge 7 is lowered down by half the thickness of the substrate. Thus, two cutting edges 7 and 8 are formed, arranged in two parallel planes one above the other, with the first edge being lower than the second by d / 2. The lines of both cutting edges remain parallel to each other and are shifted one relative to the other by a predetermined distance. After scribing (cutting), a razor blade is formed with the required overall dimensions - Figure 5. The side wall 10 serves as the holder of the first working area of the blade with the lower cutting edge 7. Figure 6 presents a top view of the structure of the resulting blade.

Similarly, a blade with three or more cutting edges can be made. The number of windows 4 corresponds to the number n of specified cutting edges of the blade, and the number of windows 5 corresponds to the value (n-1). In each of the windows 5, the etching depth is set in such a way as to ensure a sequential increase in the thickness from one working area with a cutting edge to the next by Δ / h = d / n. In Fig.7 shows the design of the blade with three cutting edges 7, 8 and 9 with a view in section and Fig.8 is the same design with a top view. In this case, Δh = d / 3.

Chemical anisotropic etching of a silicon wafer with an orientation of (100) gives an etching angle of 54 °, which provides the necessary sharpness of the cutting edge. So, in the well-known solution [3], the blade sharpening angle after applying all the additional coatings is ~ 80 °.

Thus, in the process of manufacturing a blade of the desired configuration, a predetermined number of cutting edges of the required sharpness is simultaneously formed, which is impossible for steel blades of known designs. In addition, under natural conditions of use of the blade, the thickness of the natural oxide formed on silicon, including the cutting edge, is several tens of angstroms; therefore, an oxide film, mainly SiO ₂ , in contrast to Fe ₂ O ₃ (rust) for steel blades can't dull her. No additional protective coatings of the working area of the blade is required. The design of the cartridge holder of the proposed blade does not fundamentally differ from known devices.

Another single-crystal material with a sufficient degree of hardness, for example, gallium phosphide, silicon carbide, etc., can also be used as the substrate material for the manufacture of the blade.

The proposed blade design provides a long razor life, is practical to use and easy to manufacture. The formation of several work areas in a single technological cycle, using standard operations and equipment, and not requiring highly skilled performers, reduces the complexity of manufacturing and, as a result, the cost of the entire blade.

List of sources of information:

1. US 5603161, patent, B 26 V 21/54, 1997.

2. RF 2119424, patent, В 26 В 21/00, 1998.

3. RF 2108234, patent, В 26 В 21/54, 1998.

Claims (2)

1. A razor blade containing a substrate with a wedge-shaped pointed cutting edge, characterized in that the substrate is made of solid single-crystal material and contains n work areas with wedge-shaped cutting edges located in different parallel planes one above the other, with each subsequent edge parallel shifted relative to the previous in one direction, with each subsequent working area increasing in thickness by Δh = d / n, where d is the thickness of the substrate; n = 2, 3, 4 ... 2. A method of manufacturing a razor blade, which consists in forming a substrate with pointed wedge-shaped cutting edges, characterized in that the substrate is formed of a solid single-crystal material on which anisotropic etching along crystallographic planes through the entire thickness of the substrate d in specially formed n windows on its reverse side get n cutting edges in them, located on the same plane and parallel to each other, and then by isotropic etching through windows located on the top the first surface of the substrate above each working area with a cutting edge, in addition to the last one, form working areas stepwise increasing in thickness, and an increase in thickness of each subsequent corresponds to Δh = d / n, where d is the thickness of the substrate; n = 2, 3, 4 ...

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