JPH06320320A - Cutting work method - Google Patents

Abstract

PURPOSE:To obtain high speed in cutting speed and feed speed of an end mill. CONSTITUTION:A route of feeding an end mill 16 is set, so that a cutting direction of the end mill 16 is provided always equal to the direction of relatively moving a workpiece 12 relating to this end mill 16. That is, the end mill 16, performing the so-called down cut, is moved in a direction of separating from cutting chips. Consequently, by preventing the cutting chips from easily biting in an edge groove of the end mill 16, high speed can be obtained in cutting speed and feed speed of the end mill 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting method for machining a recess having a predetermined shape on a surface of a material by feeding a rotary cutting tool along a tool path.

[0002]

2. Description of the Related Art A conventional technique related to this will be described with reference to FIG. This technique is a technique for processing a die for casting, forging or sintering by cutting a material (hereinafter referred to as a work 2) while feeding the end mill 6 along a tool path. A plan view of the work 2 is shown in FIG. Here, this work 2
A substantially cruciform portion represented by a two-dot chain line in the center of is a portion which is cut and becomes a molding surface (recess 4) of the mold. According to the conventional cutting method, the tool path 6k of the end mill 6
Are set parallel to the contour 4e of the recess 4. Then, first, the portion of the contour 4e of the recess 4 is shown in FIG.
When it is cut into a groove shape as shown in (B), next, the end mill 6 moves in the radial direction to a position of an adjacent tool path 6k with a predetermined cutting amount M (hereinafter referred to as pick feed amount M). To be done. Then, the end mill 6 is fed parallel to the contour 4e following the tool path 6k adjacent thereto, so that the side wall of the groove that is initially cut is scraped in parallel by the pick feed amount M. Thereafter, the cutting is repeatedly performed in the same manner as described above, so that the entire inside of the recess 4 is cut.

[0003]

However, according to the above-mentioned conventional cutting method, when the contour 4e of the recess 4 is first cut, groove-shaped cutting (groove cutting) is performed. As shown in (C), the end mill 6
All the front side surfaces W of the above contact the work 2. For this reason, for example, when the end mill 6 is rotating to the right, the cutting direction and the moving direction of the workpiece 2 are opposite on the left side in the traveling direction of the end mill 6, and so-called up-cutting occurs. On the other hand, on the right side in the traveling direction of the end mill 6,
The cutting direction and the moving direction of the workpiece 2 are the same, which is so-called downcut. In the case of down-cutting, since the end mill 6 is moved in a direction away from the chips, it becomes difficult for the chips to bite into the blade groove and the cutting resistance also becomes small. However, in the case of upcut,
Since the chips are pushed out by the blade groove, the chips are easily caught in the groove and the cutting resistance is increased. Therefore, it is difficult to increase the cutting speed and the feed speed of the end mill 6 by the conventional cutting method in which the up-cut and the down-cut are performed at the same time, and the performance of the cutting machine cannot be sufficiently exhibited. There's a problem. Therefore, it takes a long time to process the work 4. The technical problem of the present invention is to set the tool path of the end mill 6 so as to always perform a downcut, thereby making it difficult for chips to bite into the blade groove of the end mill 6 and to increase the cutting speed and the feed speed. It is intended to be realized.

[Means according to Claim 1 for Solving the Problems] The above problems can be solved by a cutting method having the following steps. That is, the cutting method according to the invention of claim 1 is a cutting method for processing a concave portion of a predetermined shape on a surface of a material by feeding the rotary cutting tool along a tool path, wherein the cutting direction of the rotary cutting tool is , The tool path is set so that the material always moves in the same direction as the material relative to the rotary cutting tool. [Operation of the invention described in claim 1] According to the present invention,
The cutting direction of the rotary cutting tool is always the same as the direction in which the material moves relative to the rotary cutting tool. That is, in order to be a so-called down cut, the rotary cutting tool,
Always moved away from the chips. For this reason,
It becomes difficult for chips to bite into the groove of the rotary cutting tool,
The cutting speed and feed speed of the rotary cutting tool can be increased. [Effect of the invention described in claim 1] According to the present invention,
Since the cutting process is always performed in the down cut state,
It becomes difficult for chips to bite into the groove of the rotary cutting tool, and the cutting speed and feed speed can be increased. Therefore, the processing time of the work is shortened. Also, the tool cost is reduced because the life of the rotary cutting tool is extended. further,
Since the number of tool changes is reduced, the time required for setup work is shortened.

[Means according to Claim 2 for Solving the Problems] The above-mentioned problems can be solved by a cutting method having the following steps. That is, the cutting method according to the invention of claim 2 is the cutting method according to claim 1, wherein the radius R of the curved portion of the tool path is M, the cutting amount in the radial direction of the rotary cutting tool is M, When the tool radius of the rotary cutting tool is r, it is represented by R> (2r-M) M / 2 (r-M). [Operation of the invention described in claim 2] According to the present invention,
If the cutting amount M in the radial direction of the rotary cutting tool and the tool radius r of the rotary cutting tool are determined, the radius R of the curved portion of the tool path that causes a downcut can be obtained accordingly. For this reason, for example, even when the tool path has to have a complicated shape, it is necessary to keep the radius R of the bent portion at a predetermined value or more and always
It is possible to easily design a tool path that results in a down cut. [Effect of the invention described in claim 2] According to the present invention,
The design cost can be reduced because the tool path that can be downcut can be easily designed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cutting method according to an embodiment of the present invention will be described below with reference to FIGS. The present embodiment is a cutting method in the case of cutting a die from a high hardness material (hereinafter, referred to as a work 12) using a flat end mill 16, and a bed type milling machine 50 shown in FIG. The cutting method is performed. The bed type milling machine 50 includes a column 56 that supports a main shaft 54 on a bed 52, and the column 56 can move on the bed 52 in the longitudinal direction (Z-axis direction). Further, the column 56 is supported so as to be movable in the up-down direction (Y-axis direction) while the spindle 54 is held horizontally, and is flat in a spindle hole (not shown) of the spindle. The end mill 16 is mounted. Also, on the bet 52,
A table 58 is installed so as to be movable in the width direction (X-axis direction) of the bed 52, and a vise 59 b and an ikele 59 for gripping the work 12 are placed on the table 58.
e is placed. With this structure, the table 5
8 and the column 56 are moved on the bed 52 in the X-axis and Z-axis directions, respectively, and the main shaft 54 is further moved in the Y-axis direction, whereby the flat end mill 16 is moved.
Are sent to the work 12 in the X-axis, Y-axis, and Z-axis directions for cutting. The flat end mill 16 rotates clockwise.

Next, a method of cutting the work 12 according to this embodiment will be described. FIG. 4 shows the XY of the work 12.
FIG. 3 is a plan view showing a concave portion 1 in which a substantially cross-shaped portion represented by a chain double-dashed line is formed by cutting in the center of the work 12.
4 contour 14e. 3 is a detailed view of the right end portion of FIG. According to the cutting method according to the present embodiment, the tool path 16k of the flat end mill 16 (movement locus of the center of the flat end mill 16) is irrespective of the planar shape of the recess 14 formed in the work 12 as shown in FIGS.
In the figure, as shown by the dotted line, the distances are set to a distance M from the end and are set in parallel. In the figure, the tool path 16
Although k is shown only in part, it is actually a portion where the recess 14 is formed (hereinafter referred to as a cut portion 14).
Is set over the entire range so that the whole is cut. Then, first, the flat end mill 16 is fed along the tool path 16k (1) to cut the right end portion of the cutting portion 14 with a predetermined width. Here, as described above, since the flat end mill 16 is rotating in the right direction, as shown in FIG. 1A, the portion of the right side surface W with respect to the feed direction of the flat end mill 16 is always The cutting is performed in the so-called down-cutting. Here, a dashed-dotted line 14d in the drawing is a step portion 14d formed by cutting the work 12 by sending the flat end mill 16 following the tool path 16k.

Next, the flat end mill 16 is moved by a distance M in the radial direction, positioned at the position of the tool path 16k (2), and fed along the tool path 16k (2). As a result, the cutting portion 14 is cut with the width of the dimension M from the step 14d formed by the previous cutting, that is, the cutting along the tool path 16k (1). Therefore, the cutting portions 14 are adjacent to each other. A width corresponding to the distance M between the paths 16k is cut.Hereinafter, the width M (cut amount M) cut is referred to as a pick feed amount.Next, the flat end mill 16 is moved by a distance M in the radial direction. Then, it is positioned at the position of the tool path 16k (3) and is sent following the tool path 16k (3).
As a result, the cutting portion 14 is cut with the pick feed amount M from the step portion 14d formed by the previous cutting. In this way, the flat end mill 16 is sequentially fed following each tool path 16k,
The cutting portion 14 is sequentially cut from the end with a pick feed amount M. Then, when the flat end mill 16 passes through all the tool paths 16k, the cutting portion 1
Finally, all 4 is cut to form the recess 14. If the rotation of the flat end mill 16 is counterclockwise, the direction in which the flat end mill 16 is fed is opposite to that described above, and as shown in FIG. Cutting will be performed in the W portion.

Next, a method for determining the tool path 16k that always causes a downcut from the tool radius r and the pick feed amount M will be described. Here, in the case of the flat end mill 16, as shown in FIG. 19 (A), the tool radius r matches the radius of the flat end mill 16. In the straight part of the tool path 16k, as is clear from FIGS. 1 and 3, the pick feed amount M is flat.
If it is smaller than the radius r of 6, the downcut is always performed. Therefore, r> M is a prerequisite for downcut. Further, in the curved portion of the tool path 16k, the radius R of the curved portion (hereinafter, referred to as the tool path radius R) can be set to an appropriate value so that the downcut can always be performed.

Next, referring to FIG. 2, the tool path radius R which is a down cut from the tool radius r and the pick feed amount M
The procedure for determining is explained. In FIG. 2, (K1)
Is the tool path 16k at the time of the previous cutting, and (G1)
Indicates a step portion 14d formed by cutting the work 12 by the flat end mill 16 moving along the tool path (K1). Also, (K2) is the pick feed amount M from the tool path (K1) at the time of the previous machining.
This is the tool path 16k that has been moved in parallel only, and represents the tool path 16k at the time of cutting this time. Furthermore, (G2) is
The flat end mill 16 moves along the tool path (K2) to show the stepped portion 14d formed by cutting the work 12. Therefore, the hatched portion is the region cut by this machining.

Now, consider the case where the center of the flat end mill 16 is at the point PA on the tool path (K2) (FIG. 2).
(See (A)). At this time, the range cut by the flat end mill 16 is between the point PB and the point PC. Therefore, the cutting amount N when the flat end mill 16 is fed following the tool path (K2) is the distance between the point PC and the point PH (the intersection of the perpendiculars drawn from the point PB to the line segments PA and PC). Will be equal. Further, if the center PO of the curved portion of the tool path K1 at the time of the previous machining is the origin, the point P
The coordinates of A, point PB, and point PC are as follows. Point PA; (Rcos θ, Rsin θ + M) Point PB; ((R + r) cos α, (R + r) sin α) Point PC; ((R + r) cos θ, (R + r) sin θ + M) Also, the tool at the time of machining If the center of the curved portion of the route K2 is PQ and the distance between the points PQ and PB is I, then from the triangles PQ, PB and PH, I ² = (R + r−
N) ² + (r ² − (r−N) ² ) ... (1) is obtained, and I ² = (R + r) from the triangles PQ, PB, and PE.
² cos ² α + ((R + r) sin α−M) ² (2) Expression is obtained.

By rearranging the equations (1) and (2), N = (M / R) ((R + r) sin α- (M /
2)) ... (3) Formula is obtained. In the equation (3), N becomes maximum when sin α = 1, that is, when α = 90 °. Here, FIG. 2 (B) shows the position of the flat end mill 16 when α = 90 °. That is, the point PB
Is maximized when is in the position of PB '. Therefore, r> N (α = 90 °) = (M / R) ((R + r) −
If it is (M / 2)), the down cut is always performed. When this formula is arranged, R> (2r−M) M / 2 (r−M)
... (4) Formula is obtained. That is, by setting the tool path radius R so as to satisfy the expression (4), it is possible to always make the down cut even in the curved portion of the tool path 16k.

In FIG. 6, in the equation (4), the boundary value of the tool path radius R which is a down cut is obtained while increasing the pick feed amount M in a state where the tool radius r is constant, and this is shown in a graph. It is a thing. Here, in FIG. 6, φ10
F represents the change in the boundary value of the tool path radius R (hereinafter referred to as the boundary line) in a flat end mill with a diameter D of 10 mm (r = 5 mm), and φ20F has a diameter D of 20 mm (r
= 10 mm) flat end mill, φ30F has a diameter D
30mm (r = 15mm) flat end mill, φ100F
Indicates a boundary line in a flat end mill having a diameter D of 100 mm (r = 50 mm). Here, in order to achieve the downcut, R> (2r-M) M / 2 according to the equation (4).
Since it is (r−M), the region above the boundary line of each flat end mill 16 is the downcut region. Further, the area below the boundary line is an area in which downcuts and upcuts are mixed. FIG. 7 shows the boundary line of the tool path radius R while changing the ratio (M / r) of the pick feed amount M and the tool radius r instead of the pick feed amount M in the state where the tool radius r is constant. It is a graph. Also in this graph, the region above the boundary line of each flat end mill 16 is the downcut region.

In FIG. 8, the boundary line (φ20F) of the tool path radius R in a flat end mill having a diameter D = 20 mm is a solid line, and the ratio of upcut is 5% in a region where downcut and upcut are mixed. The boundary line when changing to 50% is shown by a dotted line. Here, the ratio of the upcut in the case where the downcut and the upcut are mixed, as shown in FIG. 9, when the flat end mill 16 is fed in the direction of the arrow, the cut amount d of the portion to be the downcut. Is expressed by the ratio of the cut amount a of the portion to be up cut.

FIG. 10 shows φ10F (diameter D in FIG. 6).
= 10 mm flat end mill), the cutting conditions in the cutting method according to the present embodiment and the cutting conditions in the conventional cutting method are entered. In the cutting method according to the present embodiment, in the case of a flat end mill having a diameter D = 10 mm, the pick feed amount M is set to 1 mm and the axial cutting amount L (cutting depth) is set to 10 mm. The route radius R is set to 5 mm. Therefore, when this is represented on the graph, it becomes the point P11, and it can be seen that it is in the downcut region. On the other hand, in the conventional cutting method, the pick feed amount M is set to 5 mm, the axial cutting amount L is set to 3 mm, and the tool path radius R is not taken into consideration, so R = 0. Therefore,
When this is shown on the graph, it becomes a point Q11, and it can be seen that it exists in a region where upcut and downcut are mixed. FIG. 11 shows the ratio (M / r) of the pick feed amount M and the tool radius r on the horizontal axis, which is expressed differently from that of FIG.

FIG. 12 shows φ20F (diameter D in FIG. 6).
= 20 mm flat end mill), the cutting conditions in the cutting method according to the present example and the cutting conditions in the conventional cutting method are entered. In the cutting method according to the present embodiment, in the case of a flat end mill with a diameter D = 20 mm, the pick feed amount M is 1 mm, 2 mm, 3 mm.
It can be set to three types, and the axial depth of cut L is set to 20 mm. The tool path radius R is set to 10 mm. Therefore, when this is represented on the graph, the points P21, P22, and P
It is 23, which means that it is in the downcut area. On the other hand, in the conventional cutting method, the pick feed amount M is 10
mm, the cut amount L in the axial direction is set to 3 mm, and since the tool path radius R is not taken into consideration, R = 0. Therefore, when this is represented on the graph, it becomes a point Q21, and it can be seen that it exists in a region where upcut and downcut are mixed. FIG. 13 shows the ratio (M / r) of the pick feed amount M and the tool radius r on the horizontal axis.
It is expressed by changing the expression method to 2.

As described above, according to this embodiment, since the cutting is always performed in the down-cut state, it is difficult for the chips to be caught in the blade groove of the flat end mill 16, and the cutting speed and the feed speed are increased. It will be possible. Also,
In the present embodiment, an example in which the flat end mill 16 is used to cut the work 12 at a high speed has been shown, but a ball end mill can be used to cut the work 12 at a high speed in a similar manner. Here, in the case of the ball end mill, since the rotational shape of the cutting edge is spherical, assuming that the radius of the sphere is t, the tool radius r is r = t sin φ as shown in FIG. 19 (B). expressed. Therefore, R>
(2r-M) M / 2 (r-M) ... In the equation (4), r = tsi
By substituting nφ, the flat end mill 1
As in the case of 6, it is possible to determine the tool path radius R that results in a downcut.

FIG. 14 shows the cutting speed (m / min) and the feed amount per revolution when the work 12 (steel hardness for hot working ... H _R C42) is cut in the cutting method according to this embodiment. (Mm / rev), cutting speed (m / min) and feed per revolution (mm / re) when cutting with the conventional cutting method.
v) is shown. Here, φ10F in FIG. 14 is
The data is obtained when the cutting method according to the present embodiment is performed using a flat end mill with a diameter D of 10 mm. The pick feed amount M is 1 mm and the axial cutting amount L is 10 m.
m and tool path radius R are set to 5 mm. Also, φ
20F is data when the cutting method according to the present embodiment is carried out using a flat end mill having a diameter D of 20 mm. The pick feed amount M is 2 mm, the axial cutting amount L is 20 mm, and the tool path radius R is 20 mm. Is set to 10 mm. Note that φ10R and φ20R are data when the cutting method according to the present embodiment is performed using the ball end mill having the diameter D of 10 mm and 20 mm. Furthermore, Q11 is
The data is obtained when a conventional cutting method is performed using a flat end mill with a diameter D of 10 mm. The pick feed amount M is set to 5 mm and the axial cutting amount L is set to 3 mm. Further, Q21 is data when a conventional cutting method is carried out using a flat end mill with a diameter D of 20 mm, and the pick feed amount M is set to 10 mm and the axial cutting amount L is set to 3 mm. . As the tool to be used, a cemented carbide tool is used in both the cutting method according to the present embodiment and the conventional cutting method. As shown in FIG. 14, in the conventional cutting method, the cutting speed is about
While the limit is 70 m / min, in the cutting method according to the present embodiment, the cutting speed is 130 m / min with the flat end mill.
It can be used in the above areas, in the area where the cutting speed is 250 m / min or more with the ball end mill. In addition, the feed rate per revolution is 0.2 mm / rev in the conventional cutting method.
However, in the cutting method according to the present embodiment, the flat end mill can achieve 0.9 mm / rev or more, and the ball end mill can achieve 0.25 mm / rev or more.

FIG. 15 shows the total cutting distance (when one tool is used) when the pick feed amount M is changed when the cutting method according to this embodiment is carried out using a flat end mill having a diameter D of 20 mm. Represents the distance that can be cut by = tool life) and the total cutting amount. The rotation speed of the flat end mill is set to 3000 rpm, the feed rate is set to 4000 mm / min, and the axial depth of cut L = 20 mm (L = D). When the pick feed amount M in the radial direction is set to 1 mm, that is,
When M = 0.05D, the cutting amount per minute is as small as about 80 cm ³ , but the total cutting distance that can be cut with one flat end mill is as long as 45 m, so the total cutting amount is about 900 cm. ^It becomes relatively large as ³ . When the pick feed amount M in the radial direction is set to M = 2 mm, that is, when M = 0.1 D, the cutting amount per minute increases to about 160 cm ³ , but the cutting resistance also increases. Total cutting distance is 2
Reduced to 5m. However, the total cutting amount is as large as about 1000 cm ³ because the increase in cutting amount has a greater effect. Also, when setting the radial direction of the pick-feed quantity M = 3 mm, although the amount of cutting per minute is increased to about 240 cm ^3, due to the large influence of increase in the cutting resistance, the total cutting distance of about It will be greatly reduced to 11m. Therefore, the total cutting amount is reduced to about 660 cm ³ . Therefore, it can be seen that it is most efficient to use the pick feed amount M = 2 mm (M = 0.1 D) in the radial direction.

FIG. 16 shows data obtained when the cutting method according to the present embodiment was carried out using a ball end mill having a diameter D (= 2t) = 10 mm, and the rotation speed of the ball end mill was set to 6000 rpm. In the state, the relationship between the feed rate and the machining distance (distance that can be cut by one tool = tool life) is shown. If the feed rate is 2100 mm / min, as shown by point B11, the distance that can be cut with one ball end mill is about 45000 mm, and the feed rate is 3000 mm / m.
When used as in, the distance that can be cut with one ball end mill is about 32000 mm, as indicated by point B12.
When the same ball end mill is used in the conventional cutting method, the machining distance is about 3200 as shown by point C11 at the rotation speed of 2500 rpm and the feed rate of 200 mm / min.
It will be 0 mm. Therefore, if the cutting method according to the present embodiment is used, even if the rotation speed is set to 2.4 times the conventional value and the feed rate is set to 15 times the conventional value, the distance that can be cut with one tool, that is, the tool life is It becomes almost equal to the conventional one. In addition, FIG.
Represents the relationship between the number of revolutions and the processing distance when the feed speed of the ball end mill is set to 2100 mm / min (see points B21 to B24). As shown in the figure, when the feed rate is 2100 mm / min, the rotation speed is 7000 rp.
It can be seen that the use at m is the most efficient because the machining distance (tool life) is the longest. Incidentally, point C11 represents the tool life according to the conventional cutting method, and the processing conditions are the same as in the case of FIG. 16 (rotation speed 2500 rpm, feed rate 200 mm / min).

FIG. 18 shows the machining amount per minute when four types of cutting tools (flat end mills 10 mm, 20 mm and ball end mills 10 mm, 20 mm) are used to carry out the cutting method according to this embodiment ( Cutting amount cm ³ ) and the amount of processing per minute when using the conventional cutting method (cutting amount cm)
^This is a comparison with ³ ). First, in the case of a flat end mill 10 mm (φ10F), the conventional cutting method uses a rotation speed of 1600 rpm, a feed rate of 200 mm / min, and a pick feed rate of M.
= 5 mm and axial depth L = 3 mm, the cutting amount is 3 cm ³ / min. On the other hand, in the cutting method according to the present embodiment, the rotation speed is 4500 rpm and the feed amount is 40
When used at 00 mm / min, pick feed amount M = 1 mm (M = 0.1 D) and axial cutting amount L = 10 mm (L = D), the cutting amount is 40 cm ³ / min. That is, about the conventional
13 times. In the case of a flat end mill 20 mm (φ20F), the number of revolutions is 1200 rpm and the feed rate is 20 in the conventional cutting method.
When used with 0mm / min, pick feed rate M = 10mm and axial depth L = 3mm, the cutting rate is 6 cm ³ / m.
becomes in. On the other hand, in the cutting method according to the present embodiment, the rotation speed is 3000 rpm, the feed amount is 4000 mm / min, the pick feed amount M = 2 mm (M = 0.1 D), and the axial cutting amount L = 20 mm (L = D). The cutting amount is 160 when used with
It will be cm ³ / min. That is, it is about 26 times that of the conventional method.

In the case of a ball end mill 10 mm (φ10R), the number of revolutions is 3000 rpm and the feed amount is 20 in the conventional cutting method.
When used at 0 mm / min, pick feed rate M = 0.5 mm and axial depth of cut L = 0.5 mm, the cutting rate is 0.
It will be 06 cm ³ / min. On the other hand, in the cutting method according to the present embodiment, the rotation speed is 8000 rpm, the feed amount is 2100 mm / min, the pick feed amount M = 0.5 mm, and the axial cutting amount L.
= 0.5mm, the cutting amount is 0.26cm ³ / min
Becomes That is, it will be about four times that of the past. Ball end mill
In the case of 20 mm (φ20R), the number of revolutions is 2500 rpm, the feed rate is 200 mm / min, and the pick feed rate is M =
When used with 1 mm and an axial depth of cut L = 1 mm, the cutting rate is 0.2 cm ³ / min. On the other hand, in the cutting method according to the present embodiment, the rotation speed is 7,000 rpm and the feed amount is
When used with 2100 mm / min, radial pick feed amount M = 1 mm and axial depth L = 1 mm, the cutting amount is 2.2 cm ³ / min. That is, it is 11 times that of the conventional method.

[0023]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the principle of a cutting method according to an embodiment of the present invention.

FIG. 2 is a detailed view showing a tool path of a flat end mill.

FIG. 3 is a plan view showing a tool path of a flat end mill.

FIG. 4 is an overall plan view of a work.

FIG. 5 is an overall schematic view of a bed type milling machine used in this embodiment.

FIG. 6 is a graph showing a relationship between a tool path radius and a pick feed amount.

FIG. 7 is a graph showing the relationship between the tool path radius and the ratio of the pick feed amount to the tool radius.

FIG. 8 is a graph showing a relationship between a tool path radius and a pick feed amount in a flat end mill having a diameter of 20 mm.

FIG. 9 is a plan view showing the ratio of downcut and upcut.

FIG. 10 is a graph showing a relationship between a tool path radius and a pick feed amount in a flat end mill having a diameter of 10 mm.

FIG. 11 is a graph showing a relationship between a tool path radius and a ratio of a pick feed amount to a tool radius in a flat end mill having a diameter of 10 mm.

FIG. 12 is a graph showing a relationship between a tool path radius and a pick feed amount in a flat end mill having a diameter of 20 mm.

FIG. 13 is a graph showing a relationship between a tool path radius and a ratio of a pick feed amount to a tool radius in a flat end mill having a diameter of 20 mm.

FIG. 14 is a graph comparing a cutting method according to the present embodiment with a conventional cutting method.

FIG. 15 is a graph comparing the cutting method according to the present example with a conventional cutting method.

FIG. 16 is a graph comparing the cutting method according to the present example with a conventional cutting method.

FIG. 17 is a graph comparing the cutting method according to the present example with a conventional cutting method.

FIG. 18 is a graph comparing the cutting method according to the present example with a conventional cutting method.

FIG. 19 is a side view showing tool radii of a flat end mill and a ball end mill.

FIG. 20 is a schematic view showing a conventional cutting method.

[Explanation of symbols]

 12 Work (material) 14 Recess 16 Flat end mill (rotary cutting tool) 16k Tool path M Pick feed amount L Axial depth of cut W Cutting area r Tool radius R Tool path radius

Claims (2)

[Claims] 1. A cutting method in which a rotary cutting tool is fed along a tool path to form a recess of a predetermined shape on a surface of a material, wherein the cutting direction of the rotary cutting tool is the relative to the rotary cutting tool. A cutting method characterized in that the tool path is set so that the direction of relative movement of the material is always the same. 2. The cutting method according to claim 1, wherein the radius R of the curved portion of the tool path is M, the depth of cut in the radial direction of the rotary cutting tool, and r is the tool radius of the rotary cutting tool. In this case, R> (2r-M) M / 2 (r-M).