WO2002066189A1

WO2002066189A1 - Cutting method by rotary tool

Info

Publication number: WO2002066189A1
Application number: PCT/JP2002/001552
Authority: WO
Inventors: Shinjiro Yamada; Seiki Sato; Shinichi Abe; Takashi Inomata; Naoki Horiguchi; Kazuyasu Suda; Jun Nishijima
Original assignee: Incs Inc.
Priority date: 2001-02-23
Filing date: 2002-02-21
Publication date: 2002-08-29
Also published as: JP2002254232A

Abstract

A cutting method capable of cutting with a high accuracy in short working time to form a recessed part (W) at least partly formed of a curved surface in a material, comprising the steps of sorting the numerical data on the formed recessed part into the numerical data on a plurality of recessed part sections formed by dividing the recessed part by contour lines, cutting contour grooves by using a first rotary tool, cutting the areas surrounded by the contour grooves cut in the previous step by using a second rotary tool larger in diameter than the first rotary tool, cutting the contour grooves in the bottom surfaces of the recessed portions formed in the previous step by using the first rotary tool, cutting the areas surrounded by the contour grooves cut in the previous step by using the second rotary tool, and repeating these steps until the recessed part is formed in the material.

Description

Specification

Cutting method with rotary tool

Technical field

The present invention relates to a cutting method, and more particularly, to a cutting method for forming a concave portion, a convex portion, and the like including a curved surface in a material by a cutting process using a rotary blade.

Height

A method of forming concave portions and convex portions in a material such as a material by cutting is to rotate a cutting tool such as a drill or an end mill with a so-called spin drunit and cut the material to form concave portions and convex portions in a desired shape. There is a way to do it.

In particular, when forming concave and convex portions having fine irregularities such as a molding die, machining by electric discharge machining is also performed.

In the cutting method, in which concave parts and convex parts are formed by cutting using a spindle unit as described above, the amount of cutting per unit time is reduced by using a thin drill or a mill to increase processing accuracy. Therefore, a long working time is required until the concave and convex portions are completed. On the other hand, if a tool having a large cutting portion with a large removal amount is used, fine processing cannot be performed on the concave portion, the convex portion, and the like. For this reason, for example, in the concave portion for mold cavity, the concave portion is roughly cut with a thick cut portion. Kaloe is performed, and finally, the surface of the concave portion is finally finished with a tool having a cutting part for fine finishing.

Further, in the electric discharge machining, it takes time and cost to prepare an electrode for electric discharge machining, and it is difficult to machine a machining portion located at the back of the concave portion. The present invention focuses on the above points, and has as its basic object to provide a cutting method capable of performing high-precision cutting in a short working time. Disclosure of the invention

In order to solve the above-mentioned problems, the present invention provides a method for forming a concave portion having at least a part formed of a curved surface in a material. This method divides (a) the numerical value of the concave portion to be formed into a numerical value for each of a plurality of concave portions having different heights at upper and lower positions divided by contour lines divided by a predetermined height difference. And (b) using the elongated first rotating tool having cutting edges formed on the tip and side surfaces based on the numerical data for each of the concave portions, along the contour line that defines the highest concave portion. A step of cutting a contour groove having a depth equal to the thickness of the highest concave portion inside of the first groove; and (c) a second groove thicker than the first rotary tool based on numerical data for each concave portion. (D) cutting the region surrounded by the contour groove cut in the previous step using the rotary tool of (1), and forming the highest concave portion on the surface of the material in a shape having a flat bottom; ) Based on the numerical data for each of the concave portions, using the first rotating tool The bottom of the concave portion formed in the previous step, following the concave portion formed in the previous step, is equal to the thickness of the concave portion inside the contour line along the contour line that divides the concave portion having a height. Cutting a contour groove having a depth, and (e) cutting an area surrounded by the contour groove cut in the previous step using the second rotary tool based on the numerical data for each of the concave portions. Forming a new recess having a continuous and flat bottom surface under the already formed recess; and (f) until the recess is formed in the material, (d) and (e). ) Is repeated.

According to such a configuration, the surface of the concave portion is cut by a thin rotary blade, so that fine processing can be performed, processing accuracy is improved, and in some cases, finishing processing is unnecessary. Become.

Further, the present invention provides a method for forming a convex portion at least partially constituted by a curved surface on a material. This method comprises the steps of: (a) forming a numerical value of a concave portion surrounding a convex portion to be formed by different heights vertically separated by contour lines divided by a predetermined height difference; (B) based on the numerical data for each of the concave portions, using a first elongated rotary tool having cutting edges formed on the tip and side surfaces. Cutting a contour groove having a depth equal to the thickness of the highest concave portion inside the contour line along the contour line defining the high concave portion; and (c) numerical value data for each concave portion. Based on the above, using a second rotating tool thicker than the first rotating tool, the area outside the contour groove cut in the previous process is cut, and the highest concave portion is formed into a shape having a flat bottom. (D) using the first rotating tool, on the bottom surface of the concave portion formed in the previous process, based on the numerical value data for each concave portion, Along a contour line that defines a concave portion having a height next to the formed concave portion, the inside of the contour line is A step of cutting a contour groove having a depth equal to the thickness of the concave portion, and (e) cutting in the previous step using the second rotary tool based on a numerical data for each concave portion. Cutting a region outside the contour groove to form a new concave portion having a flat bottom surface continuing below the already formed concave portion; and (f) forming the concave portion in the material. Repeating steps (d) and (e) until

Even with such a configuration, the surface of the convex portion is cut by a thin rotary blade, so that fine processing is possible, processing accuracy is improved, and, in some cases, finishing processing is performed. It becomes unnecessary.

In one embodiment, prior to cutting the contour groove by the first rotating tool, the guide groove along a cutting line on which the contour groove is to be formed is formed by the first rotating tool. Form. According to such a configuration, the guide groove is formed at a more accurate position.

In one aspect of the present invention, the guide groove is formed by the first rotary tool moving a plurality of times along a cutting line.

In one aspect of the present invention, the difference in the predetermined height is 3 μm to 50 μm. Also, in one aspect, the present invention provides the first rotating tool, wherein the first rotating tool has a tip and a side face. A cutting tool provided with a cutting blade and having an elongated cylindrical cutting portion having a diameter D of 1 mm or less and a ratio LZD of the effective length L to the diameter D of 10 or more.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic perspective view of a machining center for performing a cutting process according to an embodiment of the present invention.

FIG. 2 is a side view of a ball end mill used for cutting according to the embodiment of the present invention.

FIG. 3 is a side view of a flat end mill used for cutting according to the embodiment of the present invention.

FIG. 4 is a side view of a mill having a substantially triangular tip at a cutting portion used for cutting according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a process of dividing the concave portion for forming the concave portion into the concave portion according to the first embodiment of the present invention.

FIG. 6 is a perspective view illustrating a process of dividing the concave portion for forming the concave portion into the concave portion according to the first embodiment of the present invention.

FIG. 7 is a perspective view illustrating a contour groove corresponding to the uppermost concave portion in the first embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating cutting of a contour groove for the uppermost concave portion in the first embodiment of the present invention.

FIG. 9 is a perspective view illustrating cutting of a region surrounded by a contour groove for the uppermost concave portion in the first embodiment of the present invention.

FIG. 10 is a perspective view showing the uppermost concave portion formed by cutting in the first embodiment of the present invention.

FIG. 11 is a perspective view illustrating cutting in a contour groove corresponding to the second concave portion in the first embodiment of the present invention. FIG. 12 is a perspective view illustrating cutting of a region surrounded by a contour groove for the second concave portion in the first embodiment of the present invention.

FIG. 13 is a perspective view of a recess formed by cutting in the first embodiment of the present invention.

FIG. 14 is a cross-sectional view illustrating a contour groove corresponding to the uppermost concave portion in the second embodiment of the present invention.

FIG. 15 is a perspective view for explaining contour groove cutting of the uppermost concave portion in the second embodiment of the present invention.

FIG. 16 is a perspective view for explaining cutting of the outer region of the contour groove corresponding to the uppermost concave portion in the second embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a schematic configuration of a numerical control type cutting machine (machining center) that implements a cutting method according to an embodiment of the present invention will be described.

FIG. 1 is a schematic perspective view of the machining center 1. As shown in FIG. 1, the machining center 1 includes a base 2 installed on a floor surface, and a processing section 4 disposed above the base 2. A processing table 8 on which a workpiece 6 to be cut is placed is provided below the processing section 4. The processing table 8 is configured to be able to move vertically and horizontally by a known mechanism based on numerical data for cutting.

A head 10 is provided above the processing table 8, and a unit mounting portion 14 to which the spindle unit 12 is detachably mounted is provided below the head 10. ing. The spindle unit 12 is attached to the unit mounting section 12 so that the cutting tool 16 attached to the tip of the spindle unit 12 faces the caroe table 8 and can cut the work 6 on the processing table 8. I have. The head 10 is provided with a number for cutting by a known mechanism. It is possible to move vertically and horizontally with respect to the worktable 8 based on the value data ο

A chuck is built in the unit mounting portion 14, and a force bra (not shown) at the rear end of the spindle unit 12 is coupled to the chuck, thereby connecting the spindle unit 12 to the unit mounting portion 14. It can be detachably attached and fixed. The spindle unit 12 is capable of cutting a workpiece 6 by rotating a cutting tool 16 attached to the tip of a rotatable main spindle at a speed of 500 rpm or more per minute by a built-in motor. It is.

Therefore, in the machining center 1, the worktable 6 on which the work 6 is mounted and the spin drunk unit 12 are relatively moved based on the numerical data relating to the cutting work, so that the work 6 can be moved as desired. Can be cut.

The machining center 1 is equipped with a so-called ATC (Automatic Tool Changer) that can automatically change the spindle unit 12. As shown in FIG. 1, a replacement spindle unit mounting portion 18 is provided on the side of the head 10 for mounting a replacement spindle unit. A plurality of replacement spindle units 20 to which cutting tools having different dimensions and shapes are mounted are mounted on the niche mounting portion 18.

In addition, below the head 10, a replacement unit for replacing the spindle unit 12 attached to the unit mounting portion 14 with the replacement spindle unit 20 attached to the replacement spindle unit mounting portion 18 is provided. An arm 22 is provided. In the present embodiment, the replacement spindle unit mounting section 18 sequentially moves the replacement spindle unit 20 in the direction of the replacement arm 22 by a drive mechanism (not shown), and the desired replacement spindle unit. The unit 20 is configured to be gripped by the replacement arm 22 and exchangeable with the spindle unit 12 mounted on the unit mounting portion 14. Therefore, in machining center 1, the unit is mounted on the unit mounting section 14. The work 6 can be subjected to various processes by exchanging the hinged unit 12 to be worn.

In the present embodiment, a cutting tool 16 which is a rotary tool attached to a spindle unit or a plurality of replacement spindle units 20 attached to a unit mounting portion is connected to a built-in motor output shaft. It is integrated with the main shaft. The types of cutting tools 16 include the so-called ball end mill 24 (Fig. 2), in which the tip of the cutting part is substantially hemispherical, and the so-called flat end mill 26 (Fig. 3), in which the tip of the cutting part has a flat tip. There is a mill 28 (FIG. 4) having a substantially conical cutting end. In addition, a plurality of types of ball end mills 24, flat end mills 26, and mills 28 having different thicknesses (diameters) of cutting portions are mounted on a plurality of replacement spindle units 20, respectively. Each of these minoles 24, 26, 28 has a cutting blade at the tip 24a, 26a, 28a and the side face 24b, 26b, 28b. These mills include a thin mill with a diameter D of 1 mm or less and a slender cylindrical cutting part with a ratio L / D of effective length L to diameter D of 10 or more, that is, a small diameter cutting part. And thicker mills with a larger diameter than thinner mills.

Next, according to FIGS. 5 to 13, a first embodiment of the present invention in which, for example, a concave portion serving as a cavity of a mold for manufacturing a cellular phone component is formed in a metal material for a mold (work 6). The formation of the concave portion by the cutting method described above will be described. Generally, metal materials for molds include, for example, rolled steel for general structures (SS), carbon steel for machine structures (SC, SCK), carbon tool steel (SK), alloy tool steel (SKS, SKD), High speed steel (SN C), high carbon chromium, bearing steel (SN J), nickel chromium molybdenum steel (SNC M), chromium molybdenum steel (SCM), aluminum chromium molybdenum steel (SA CM), pre-hardened steel, high tensile aluminum alloy And aluminum alloys such as duralumin (A7075) and copper alloys.

First, it was generated based on design digital data created by 3D CAD. The numerical data of the concave portion to be formed is divided into numerical data for each of a plurality of concave portions having different heights up and down, which are defined by contour lines divided by a predetermined difference in height. Specifically, the concave portion W formed by the dotted line in FIG. 5 is horizontally divided at predetermined intervals as shown in FIG. 5 and FIG. The concave portions W 1 to Wn are formed, and numerical values corresponding to the concave portions W 1 to Wn are generated. The above-mentioned predetermined interval, which is the thickness of each concave portion, is set in consideration of conditions such as the diameter of a cutting tool used for cutting the contour groove, the shape of the concave portion to be processed, and the like. For example, when the diameter of the tool to be used is extremely small, such as 0.2 mm, the diameter is about 3 m. When the diameter of the tool to be used is relatively large, such as l mm, the maximum diameter is about 50 mm. Is set. In the drawings, the thickness of each concave portion is extremely large with respect to the dimension of the work 6 for clarity.

This step may be performed by an external computer for generating numerical data of the concave portion, an external or built-in computer for controlling the machining chamber, or another computer.

Then, or simultaneously with or before this, a spindle unit on which a thin mill, in this embodiment a ball mill 24 having a diameter D of 0.4 mm and an effective length L of 10 mm, is mounted. 1 2 is mounted on the unit mounting section 1 4, and the aluminum alloy (A7705) work 6 to be cut is placed on the processing table 4 and fixed.

Next, based on the numerical data of the concave portion W1 at the highest position, while rotating the ball end mill 24 at, for example, 500 rpm or more per minute by the built-in motor of the spindle unit 12, A guide groove gl is formed along the contour line R1 using the ball-and-mill 24, which is the first slender rotating tool with cutting edges formed at the tip and side, along the contour line R1 that defines the highest concave portion W1. (Figure 7). The depth of the guide groove gl is smaller than the thickness of the concave portion W1.

The “contour line that defines the concave portion” means the concave portion and the concave portion located above and below the concave portion. And contour lines drawn at positions where the boundary surface intersects the contour surface of the concave portion. Therefore, the contour line R 1 that defines the concave portion W 1 at the highest position corresponds to the contour of the concave portion on the surface of the work 6, and the contour line R 2 that defines the second concave portion W 2 is the highest. A boundary line between the concave portion W1 at the position and the second concave portion W2 is a contour line drawn at a position crossing the contour surface of the concave portion.

Next, the cutting portion 24 c of the ball end mill 24 is moved by moving the cutting portion 24 c of the ball end mill 24 along the guide groove g 1 while rotating it at, for example, more than 50,000 rotations. Then, a vertical contour groove G1 having a depth equal to the thickness of the highest concave portion W1 is cut (FIGS. 7 and 8). The formation of the guide groove gl and the contour groove G1 is based on the numerical data of the highest concave portion W1, and the inside of the contour line R1 where the cutting portion 24c of the ball end mill 24 defines the highest concave portion W1 This is performed by relatively moving the worktable 4 on which the work 6 is placed and the spindle unit 12 so that the workpiece moves along the contour line R1. Therefore, the formed contour groove G1 is inscribed in the contour line; R1.

Next, the spindle unit 12 mounted on the spindle unit mounting section 14 is attached to a ball end mill having a cutting section 240 c larger than the ball end mill 24 used for cutting the groove. Replace the spindle unit 20 with a new one. Then, based on the numerical data of the uppermost recess W1, the area surrounded by the contour groove G1 is cut using a thick ball end mill to make the highest recess W1 into a shape with a flat bottom. Formed on the surface of work 6 (Fig. 9). In this cutting, based on the numerical value of the highest concave portion W1, the cutting portion 240 c of the ball-end mill moves in the region surrounded by the contour groove G1 and moves in the region surrounded by the contour groove G1. This is performed by relatively moving the worktable 4 on which the work 6 is placed and the spindle unit 12 so as to cut and remove the metal material inside. In the present embodiment, FIG. Along the path P, the cutting portion 240c of the thick ball-end mill moves in the area surrounded by the contour groove G1, and all the metal material in the area surrounded by the contour groove G1 is cut and removed. An uppermost concave portion W1 having a flat bottom is formed (FIG. 10).

Next, the spindle unit 12 mounted on the spindle unit mounting portion 14 is transferred to the ball end mill 24 (first rotary tool) used for cutting the guide groove gl and the contour groove G1. Then, the cutting portion 24c of the ball end mill 24 is rotated at, for example, 500,000 revolutions or more per minute, so that the cutting portion 24c is formed on the bottom surface of the uppermost concave portion W1, which is the concave portion formed in the previous process. A guide groove g 2 is formed along the contour line (that is, inscribed in the contour line) inside the contour line that defines the second concave portion W 2 at the height position next to the uppermost concave portion W 1. (Figure 11).

Next, the cutting portion 24c of the ball end mill 24 is moved along the guide groove g2 while rotating the cutting portion 24c of the ball end mill 24 at 500 or more revolutions per minute. A vertical profile groove G2 having a depth equal to the thickness of the concave portion W2 is cut. The formation of the guide groove (g 2) and the contour groove (G 2) is based on the numerical data of the second concave portion W 2, and the cutting portion 24 c of the ball end mill 24 is formed by the second concave portion W 2 Is carried out by moving the worktable 4 on which the work 6 is placed and the spindle unit 12 relatively so as to move along the contour line which defines the spindle unit again. Replace the spindle unit 12 mounted on the spindle unit 20 with a ball end mill having a cutting portion 240 c larger than the ball end mill 24 used for cutting the groove, Based on the numerical value of the second concave portion W2, the area surrounded by the contour groove G2 was cut using a thick ball end mill (Fig. 12), and the second concave portion W2 was flattened. It is formed below the uppermost concave portion W1 in a shape having an appropriate bottom. This cutting is also performed based on the numerical data of the second recess W2 in the same manner as when cutting the top recess W1. Processing in which the workpiece 6 is placed so that the cutting part 240 c of the tool moves in the area surrounded by the contour groove G2 to cut and remove the metal material in the area surrounded by the contour groove G2. This is performed by relatively moving the table 4 and the spindle unit 12. In the present embodiment, even when cutting the concave portion W2 of the No. 2 surface, the cutting portion 240 c of the ball-end mill is cut into the contour groove G2 along the path P indicated by the dashed line in FIG. The metal material in the region surrounded by the contour groove G2 is cut and removed, and the second concave portion W2 having a flat bottom is formed.

A guide groove g and a contour groove G are formed by cutting the narrow cutting portion 24c for each concave portion W, and then the metal material in the region surrounded by the contour groove G is removed by the thick cutting portion 240C. This process is repeated until the lowermost concave portion Wn is cut and formed to complete the concave portion W (FIG. 13).

The inner surface of the recess W formed in this manner is microscopically configured by a minute step-like shape whose height is the thickness of the recess, but the thickness of the recess is reduced to the dimension of the recess. By setting it to be extremely small, the inner surface becomes a substantially smooth curved surface. Therefore, the height (thickness) of the concave portion is changed according to the accuracy of the inner surface required for the concave portion.

In the above embodiment, since all the contours of the concave portion W are cut by the cut portion 24c having a small diameter, the concave portion W requires fine processing like a thin cut portion K shown in FIG. 8 and the like. Even if there is a part, it is possible to machine such a part requiring fine machining with high accuracy without changing tools.

Next, according to FIGS. 14 to 16, for example, a metal material for a mold (work 6) is used to form, for example, a convex portion forming a cavity of a mold for manufacturing a part of a mobile phone. The formation of the projections by the cutting method according to the second embodiment of the present invention will be described. In the present embodiment, the concave portion W, which is a space, surrounds the convex portion P.

In the present embodiment, the object to be formed is a convex portion, but the convex portion to be formed: a space around P ( (Recess) Since the metal material located at W is gradually removed by cutting with a rotary tool, the guide groove g and the contour groove G are formed so as to circumscribe the contour line R, and Except that the outer metal material is removed, it basically has the same configuration as the concave portion formation of the first embodiment.

That is, the numerical data of the portion (recess) to be removed from the data of the convex portion to be formed, which is generated based on the design digital data generated by the three-dimensional CAD, is calculated. The numerical data is divided into numerical data for each of a plurality of concave portions having different height positions in the vertical direction, which are defined by contour lines divided by a predetermined height difference. Next, a spindle unit 12 to which a ball mill 24 having a thin mill, in this embodiment, a diameter D of 0.4 mm and an effective length L of 10 mm is mounted is mounted on the unit mounting portion 14, and Place and fix work 6 to be machined on 4.

Next, based on the numerical data of the concave portion W1 at the highest position, while rotating the ball end mill 24 at, for example, 500 rpm or more per minute by the built-in motor of the spindle unit 12, Using a ball end mill 24, which is the first slender rotating tool with cutting edges formed at the tip and side surfaces, a guide groove gl is formed along the contour line that partitions the highest concave portion W1 . Next, the cutting part 24 c of the ball end mill 24 is moved by moving the cutting part 24 c of the ball end mill 24 along the guide groove g 1 while rotating at least 500 ° rotation or more. To cut a vertical contour groove G1 having a depth equal to the thickness of the highest recess W1 (Fig. 14, Fig. 15) o

The formation of the guide groove g 1 and the contour groove G 1 is based on the numerical value of the highest concave portion W 1, and the cutting section 24 c of the ball end mill 24 defines the highest concave portion W 1 This is performed by relatively moving the worktable 4 on which the work 6 is placed and the spindle unit 12 so as to move along the contour line outside the work. Therefore, the formed contour groove G1 circumscribes the contour line R1. Next, the spindle unit 12 mounted on the spindle unit mounting portion 14 is attached to a ball end mill having a cutting portion 240 c larger than the ball end mill 24 used for cutting the groove. Replace the spindle unit 20 with the spindle unit 20 and cut the area outside the contour groove G1 using a thick ball end mill based on the numerical data of the uppermost recess W1. The highest concave portion W1 is formed on the surface of the work 6 in a shape having a flat bottom (FIG. 16). In this cutting, based on the numerical value of the highest concave portion W1, the cutting part 240c of the ball-end mill moves in the area outside the contour groove G1 and moves in the area surrounded by the contour groove G1. This is performed by relatively moving the worktable 4 on which the work 6 is placed and the spindle unit 12 so as to perform cutting and removal.

Also in the present embodiment, similarly to the first embodiment, a guide groove g and a contour groove G are cut and formed in each of the concave portions W by a thin cut portion 24c, and thereafter, a thick cut portion 240 is formed. The step of removing the metal material in the region outside the contour groove G is repeated until the lowermost concave portion Wn is formed by cutting and the concave portion W is completed.

The outer surface of the convex portion P formed in this manner has a microscopic shape formed by minute steps whose height is equal to the thickness of the concave portion. By setting the dimensions very small for this dimension, this surface will be a substantially smooth curved surface. Therefore, the height (thickness) of the concave portion is changed according to the required surface accuracy of the convex portion.

According to such first and second embodiments, since the surface of the concave portion W or the convex portion: P is constituted by the wall of the contour groove cut by the small-diameter cutting portion, the concave portion W For example, even when it is used as a mold cavity, finishing is not required. In addition, the removal of the metal material in the area surrounded by the contour groove (first embodiment) or the area outside the contour groove (second embodiment) is performed by a thick rotary tool having a large cutting amount. This removal can be completed in a short time, Alternatively, the time required for forming the projections is reduced.

The present invention is not limited to the embodiments described above. In the above embodiment, all the concave portions have the same thickness. However, the thickness of each concave portion (the difference in the predetermined height) is set according to the inclination of the inner surface of the concave portion (or the surface of the convex portion) formed by the concave portion. For example, the thickness may be increased in a portion where the inclination is large, and the thickness may be decreased in a portion where the inclination is small.

In the above embodiment, the machining center 1 in which the spindle unit can be automatically replaced is used. However, the present invention can be implemented in a cutting machine in which the spindle unit cannot be replaced automatically or cannot be replaced. It is. In such a cutting machine, the operator manually replaces the entire spindle unit or the cutting tool (mill) in order to perform cutting with a mill having cutting sections of different diameters. Further, in the above embodiment, a ball end mill is used as a cutting tool, but other types of mills such as a flat end mill (FIG. 3), or a groove is formed by using another rotary tool, or The portion surrounded by the groove or the outer portion of the groove may be removed.

In the above-described embodiment, the guide groove and the contour groove are formed by rotating the cutting tool at 500 rpm or more, but the present invention is not limited to this rotation speed. However, for example, the number of revolutions may be more than or equal to 30000 revolutions per minute or less.

Further, the above embodiment is a cutting process for forming a concave portion in a metal material, but the present invention cuts another type of material. ] Applicable to processing.

In the above embodiment, the guide groove and the contour groove are formed by the same mill in all the concave portions, but the mill to be used may be changed depending on the concave portion.

Further, the above-mentioned predetermined interval, which is the thickness of each concave portion, may be set to be substantially the same as the cutting depth (depth) that the cutting tool to be used can cut at one time, or set to a value larger than this. You may. If it is set to a value larger than the depth of cut (depth) When cutting one concave portion, the cutting tool is moved along the cutting path a plurality of times while changing the position in the vertical (Z) direction to cut the guide groove or the contour groove, and In this case, cutting is performed in a region surrounded by or outside the contour groove.

Claims

1. A cutting method for forming a concave portion having at least a part of a curved surface in a material,

(a) dividing the numerical data of the concave portion to be formed into numerical data for each of a plurality of concave portions having different heights up and down divided by contour lines divided by a predetermined height difference;

(b) Based on the numerical data for each of the concave portions, using a first elongated rotary tool having cutting edges formed at the tip and side surfaces, the contour along the contour line that defines the highest concave portion. Cut a contour groove having a depth equal to the thickness of the highest recess inside the line:

(c) cutting a region surrounded by the contour groove cut in the previous step using a second rotary tool thicker than the first rotary tool, based on the numerical data for each concave portion, Forming a high recess on the surface of the material in a shape having a flat bottom;

(d) Based on the numerical data for each of the concave portions, the first rotary tool is used to set a height next to the concave portion formed in the previous step on the bottom surface of the concave portion formed in the previous step. Cutting a contour groove having a depth equal to the thickness of the concave portion inside the contour line along a contour line defining the concave portion;

(e) Based on the numerical data for each of the concave portions, the region surrounded by the contour groove cut in the previous step is cut using the second rotary tool to form the already formed concave portion. Forming a new recess having a continuous, flat bottom below the portion;

(f) repeating (d) and (e) until the concave portion is formed in the material.

2. A method of forming at least a portion of a convex portion having a curved surface on a material,

(a) The numerical value of the concave part surrounding the convex part to be formed is classified by a predetermined height difference Dividing into numerical data for each of a plurality of concave portions having different heights at the top and bottom defined by the contour lines;

(b) Based on the numerical data for each concave portion, using a first elongated rotary tool having cutting edges formed at the tip and side surfaces, the contour line is defined along a contour line that defines the highest concave portion. Cutting a contour groove having a depth equal to the thickness of the highest recess inside,

(c) cutting a region outside the contour groove cut in the previous step using a second rotating tool thicker than the first rotating tool, based on the numerical value data for each of the concave portions, Forming a highest concave portion on the surface of the material in a shape having a flat bottom;

(e) Based on the numerical data for each of the concave portions, the second rotary tool is used to cut an area outside the contour groove cut in the previous process, thereby obtaining the already formed concave portion. Forming a new recess having a continuous and flat bottom surface below

(f) repeating (d) and (e) until the concave portion is formed in the material.

3. The cutting method according to claim 1 or 2, wherein

Prior to cutting the contour groove by the first rotary tool, a guide groove along a cutting line on which the contour groove is to be formed is formed by the first rotary tool. Processing method.

4. The cutting method according to claim 3, wherein

The cutting method, wherein the guide groove is formed by moving the first rotary tool a plurality of times along a cutting line.

5. The cutting method according to any one of claims 1 to 4, wherein

The cutting method, wherein the difference in the predetermined height is 3〃m to 50 zm.

6. The cutting method according to any one of claims 1 to 5, wherein

The first rotary tool has an elongated cylindrical cutting portion having a cutting blade at a tip and a side surface, a diameter D of 1 mm or less, and a ratio LZD of the effective length L to the diameter D of 1 ° or more. A cutting method characterized in that it is a cutting tool that performs cutting.