JPH03178714A - End mill - Google Patents

Abstract

PURPOSE:To maintain an unchanged edge angle with the varied number of edges and obtain an end mill of excellence in edge strength by setting the rake angle of a rake face and the relief angle of a flank face in cross section perpendicular to the axial line of an edge portion in preset ranges, respectively. CONSTITUTION:The side face 14 of an end mill edge portion 13 is separated into a rake face 15 ranging from an outer periphery edge 17 to the front side in a rotational direction of a tool and a flank face 16 ranging therefrom to the rear side in a rotational direction of the tool, the rake angle theta1 of the rake face 15 being in a range from -30 deg. to -50 deg. and the relief angle theta2 of the flank face 16 being in a range from 20 deg. to 35 deg., respectively. With the edge portion side face 14 separated in this way, the rake angle theta1 and the relief angle theta2 can be set independently of the number of edges and still are set in a above- mentioned range to ensure an unchanged edge angle, and the rake angle theta1, of an outside edge 17 which is not excessively offset to a load side and the relief angle theta2 which is not excessively in short avoids chatter vibration in cutting and abnormal wear of the outer periphery edge 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an end mill used for groove cutting and side cutting, and more specifically to an end mill suitable for use in finishing machining of high-hardness materials such as molds. .

[Prior Art] When processing plastic molds, rubber molds, etc., for example, as shown in FIG. 17, rib processing is performed to form deep grooves 2 in the mold l. Finish machining of the groove 2 has conventionally relied exclusively on electrical discharge machining, since it is difficult to ensure the surface roughness of the groove wall surface 3 using normal cutting.

However, electric discharge machining has the disadvantages that it requires a long time and the machining cost is extremely high. For this reason, recently, various end mills have been provided that are particularly suitable for finishing work during rib machining.

FIGS. 18 and 19 show an example of an end mill proposed for such rib machining. The end mill 4 shown in these figures has a cross section orthogonal to the tool axis O at the tip of the tool body 6, which has a substantially cylindrical yank 5 at the base end that is fitted with the main shaft of the machine tool (as shown). forms a blade part 7 having a regular polygonal shape (regular hexagon in the illustrated example), and six peripheral blades extending over the entire length of the blade part 7 are provided at the ridge line where each side surface 8 of this blade part 7 intersects. 9..., and each peripheral cutter 9 is formed with respect to the tool axis O so as to draw a tapered axis-like rotation locus around the tool axis O in accordance with the shape of the groove 2. It is formed at a predetermined angle.

When machining the groove 2 using such an end mill, the tool body 6 is rotated about the axis O in the direction of the arrow hole, and the tool body 6 and the groove 2 are rotated.
A relative movement is applied in the longitudinal direction of the groove 2 between the grooves 2 and 2, whereby each peripheral blade 9 cuts the wall surface 3 and the groove 2 is formed. Note that the depth of cut in this case is extremely small, and is closer to the area of grinding than cutting. Further, the reason why the blade portion 7 is formed to have a polygonal cross section is to increase the edge angle of the peripheral blade 9 to eliminate chatter vibration during cutting and improve the surface roughness of the finished surface.

Here, the number of cutting blades 9 is six in the illustrated example, but is not limited to this, and various types of cutting blades with an arbitrary number of three or more are available.

[Problems to be Solved by the Invention] Incidentally, in all end mills for rib machining such as the conventional end mill 4 described above, the blade portion 7 is formed in a prismatic shape with a regular polygonal shape in cross section. 9, the rake angle θ11, that is, the cross section perpendicular to the axis 0 of the blade part 7 (19th
In the figure), the angle formed by the side surface 8a extending forward in the tool rotation direction from the cutting edge 9 with respect to the line segment Ct connecting each cutting edge 9 from the tool rotation center PO is half the apex angle in the regular polygonal cross section, If the number of cutting blades 9 is n1 line segment Q, and the angle made counterclockwise from l with cutting blade 9 as the center is positive, then θI = -πX(n-1)/n(rad,)-...・−
■It is determined by.

In addition, the relief angle θ2 of the cutting edge 9, that is, the cutting edge 9
The angle formed by the side surface 8b extending rearward in the tool rotation direction is equal to the value obtained by subtracting the rake angle θl from 90° (yr/2 rad,), and if the number of cutting edges 9 is n, θ2=πX (2-n)/2n (rad,)--■.

In this way, in the conventional end mill, as long as the blade portion 7 is formed into a regular polygonal shape, the rake angle θl and deflection angle θ2 are determined by the number n of cutting blades 9.
In some cases, the cutting edge angle (θl+03) becomes extremely small, resulting in insufficient strength of the cutting edge, which tends to cause chatter vibration and also tends to cause chasing of the cutting edge.

In addition, especially for end mills with a bottom cutter at the tip of the blade 7, even if an attempt is made to feed the tool in the axial direction to form a taper groove at once in order to improve cutting efficiency, the tip of the outer circumferential cutter is Since it is not possible to set a large feed rate in the tool axis direction due to lack of strength, the end result is to perform preliminary machining such as grooving the workpiece with a small diameter tool and then expand the diameter with an end mill to form a tapered groove. There was also the problem of having no choice but to do so.

The present invention was made against this background, and an object of the present invention is to provide an end mill that can maintain a constant cutting edge angle even when the number of cutting edges changes and has excellent cutting edge strength.

[Means for Solving the Problems] A first invention for solving the problems described above is such that the side surface of the blade portion of the end mill is formed by a rake face that extends from the peripheral cutting edge toward the front side in the tool rotation direction, and a ramp that continues from the outer peripheral edge toward the rear side in the tool rotation direction. Divide into two faces,
The rake angle of the rake face is set in the range of 30° to -50°,
The clearance angles of the flanks are set in the range of 20° to 35°.

The second invention is an end mill in which a bottom cutter and a cache are formed on the tool tip surface, in which the rake angle of the peripheral blade tip is in the range of -30° to -50°, and the relief angle of the peripheral blade tip is 20°. The angle is set within the range of 35° to 35°.

1 Effect According to the configuration of the first invention described above, by dividing the side surface of the blade part, the rake angle and clearance angle can be set regardless of the number of blades, and moreover, the rake angle and clearance angle can be set within the above-mentioned ranges. In addition to ensuring a constant cutting edge angle, the rake angle of the peripheral cutting edge does not deviate excessively to the negative angle side and the clearance angle is not excessively insufficient, so chatter vibration and abnormal wear of the peripheral cutting edge can be avoided during cutting. .

Further, according to the configuration of the second invention, by setting the rake angle and relief angle of the peripheral blade tip within the above-mentioned range, a constant cutting edge angle is ensured at the peripheral blade tip, and the rake angle is Since the angle does not increase excessively toward the negative angle side and the clearance angle does not become insufficient, abnormal wear due to chattering of the tip of the peripheral blade due to feed in the tool axis direction is avoided.

[First Embodiment 1] Hereinafter, a first embodiment according to the first invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, the end mill of this embodiment has a cylindrical shank 12 formed on the proximal end of the tool body 11, as in the conventional end mill described above. Although the end mill is formed with a blade portion 13 having a polygonal cross-section, the cross-sectional shape of the blade portion 13 is different from that of conventional end mills.

That is, in the end mill of this embodiment, the side face I4 is divided into a rake face I5 and a flank face I6, as shown in FIG. 6 extending in a straight line from the tip of 13 to the base end
The outer circumferential cutters 17 are formed at circumferential annular pitches.

Here, as shown in FIGS. 1 to 3, the cutting surface I5 is formed into a plane extending linearly from the tip to the base end of the blade portion 13. This rake 15 and the outer peripheral blade 17
The angle formed by the line segment Q3 extending from to the rotation center po, that is, the rake angle θl in the cross section perpendicular to the axis of the blade part 13
is determined to be smaller than the angle θ3 between the line segment (!3 and the flank surface 16, and specifically, the properties of the workpiece material (e.g. toughness, etc.)
, or in the range of -504° depending on cutting conditions and the like. This is because if the rake angle θ1 exceeds 30° and deviates to the conformal side, the cutting edge angle (θI+03) will be insufficient, which will induce chatter vibration during cutting and may cause chipping on the peripheral cutting edge 17. If the angle θl exceeds 150° and is largely biased toward the negative angle side, the peripheral edge 1
This is because the cutting resistance of No. 7 increases, which may hinder smooth cutting.

Further, the relief surface 16 is formed in a convex curved shape that gradually recedes toward the tool rotation center PO as it approaches the scoop 15, and the relief angle 02 of this relief surface 16 is in agreement with the axis of the blade portion 13. The angle θ2 formed by the line segment Q, 4 perpendicular to the above-mentioned line segment Q3 in the orthogonal cross section and the tangent of the portion of the relief 16 that is continuous with the cutting edge 17 is similar to the rake angle θl described above, The angle is set in the range of 20° to 35° depending on the properties, cutting conditions, etc.

This is because if the clearance angle θ2 is less than 20°, abnormal wear may occur between the clearance cutter 16 and the workpiece material, leading to premature wear of the peripheral cutting edge 17, while on the other hand, if the clearance angle θ2 exceeds 35°, This is because if the angle becomes large, the cutting edge angle (θ1+03) of the peripheral cutter 17 becomes insufficient, which may easily cause chatter vibration during cutting.

Note that this relief 16 does not necessarily have to be formed in a convex curved shape, but may be formed in a flat shape, etc., so that the relief angle θ2
It may be changed as appropriate depending on the size, processing method, etc.

In the end mill configured as described above, the tool body 11 is rotated about the axis O in the six directions of the arrows, and there is a space between the blade part 13 and the workpiece in a direction perpendicular to the tool axis O. A relative movement of 2 is applied, and as a result of this, the peripheral cutter 17 cuts the wall surface of the workpiece.

Here, in the end mill of this embodiment, since the side surface 14 of the blade portion 13 is divided into a rake 15 and a flank 16, the rake angle θl of the rake face 15 and the clearance angle θ2 of the flank 16 are set separately and independently. Moreover, since these rake angle θl and relief angle θ2 are set within the above-mentioned optimal range, a constant cutting edge angle (θl + θ3) is maintained regardless of the number of teeth, and as a result, chatter vibration and outer circumference are reduced during cutting. Chipping and early wear of the blade are reliably suppressed, improving the surface roughness of the machined surface.

In addition, in this embodiment, the rake surface is different from the conventional case in which the cutting portion 13 is formed into a regular hexagonal cross section and the ridge line on each side is used as an outer peripheral cutting edge (indicated by a two-dot chain line in FIG. 2). Since the rake angle θl of 15 decreases, the cutting resistance related to the peripheral edge 17 decreases, and as a result, the torque required during cutting decreases, and the gap S between the machined surface of the workpiece and the rake surface 15 decreases. It also has the effect that the discharging of chips generated by the larger outer peripheral cutter 17 is improved.

In this embodiment, rib machining of a mold is specifically explained, but the end mill of the present invention can be used not only for this purpose, but also for ordinary end mills that perform finishing machining and side cutting of high-hardness materials. It is widely used as a substitute for

In addition, in this embodiment, the number of cutting blades 17 is set to six, but the end mill of the present invention is not limited to this.

Below, examples of variations in the number of peripheral blades are shown in Figures 4 to 6.
This will be explained with reference to the figures.

The end mill shown in FIG. 4 is an example in which three peripheral blades 21 are formed on the outer periphery of the blade part 20, and in this case also, the side surface 20a of the blade part 20 is divided into a rake face 22 and a flank face 23. It is formed as follows.

The rake angle θI of the rake face 22 is -30° to -
Within the range of 50°, the clearance angle θ2 of the clearance 23 is 20°.
~35°, more specifically the rake angle θ
It is assumed that l is -42°30' and clearance angle θ2 is 25°.

In this modification, as in the first embodiment, the cutting edge angle (θ1+03) is determined regardless of the number of cutting edges. In comparison, the strength of the cutting edge is high and chatter vibration is less likely to occur. In addition, in the case of three-flute tool, the core thickness is increased compared to the conventional one, so there is also the effect that tool rigidity is improved. Incidentally, when the rake angle θl and clearance angle θ2 are set to the above values, the core thickness is 67.5%.

Note that the core thickness changes depending on the rake angle θI,
As shown in FIG. 5, by setting the rake angle θl larger, the core thickness can be further increased.

In the illustrated example, the core thickness was increased to 72% by setting the rake angle θ1 to -45'30' and the relief angle θ2 to 25°. However, when increasing the rake angle θ1 in this way, the width a of the relief 23 increases, and the intersection 24 of the rake face 22 and the relief face 23 and the rotation locus R of the peripheral cutter 2I The distance between the intersections 24 and 24 may decrease and the intersection 24 may interfere with the rotation trajectory R, so care must be taken. In such a case, the clearance angle θ2 is changed as shown by the broken line in FIG.
By setting a large value, interference can be prevented while preventing a decrease in core thickness.

Further, FIG. 6 shows an example of an end mill in which four peripheral blades 3I are formed on the outer periphery of the blade part 30, and in this case also, the blade part side surface 3
0a is divided into a rake face 32 and a flank face 33, the rake angle θl is set to -48° and the relief angle θ2 is set to 25°, and the cutting edge angle (θ1+03) can be set regardless of the number of teeth. This is similar to the first embodiment described above. Note that in this example, the core thickness d is 74.4%, which is greater than that in the case where there are three peripheral blades.

As shown in the above modification, the number of peripheral cutting edges can be set arbitrarily, but the number should be selected appropriately according to the tool diameter. Specifically, each peripheral cutting edge 17, 21, 31
It is preferable to increase the distance as the tool diameter increases so that the distance between them falls within a certain range.

In addition, in the first embodiment, the outer peripheral cutter 17 is particularly aligned with the tool axis O.
However, the present invention is not limited to this, and as shown in FIG.
Those formed parallel to the cylindrical locus to draw a cylindrical trajectory,
Alternatively, as shown in FIG. 8, various modifications such as one in which the peripheral blade 17 is curved in an arc shape are possible.

Furthermore, in the first embodiment, the case where the peripheral cutter 17 is a so-called straight blade in which the helix angle with respect to the tool axis O is 0° has been explained, but as shown in FIG. , conversely, it can naturally be applied to cases of left-handed twist.

Further, in the first embodiment, the pitches in the circumferential direction of each outer peripheral cutter 17 are set to be the same, but the pitch is not limited to this, and may be set at unequal pitches. In this case, the cycle of vibration energy input to the tool is not constant each time each peripheral cutting edge 17 cuts into the workpiece, so resonance of the tool is avoided and the surface roughness of the cut surface is further improved. can be improved.

Furthermore, in the first embodiment, the tip of the blade part 17 is formed in a plane perpendicular to the tool axis O, but it can also be formed in a hemispherical shape, for example, as shown in FIG. It can be modified into various shapes such as a planar shape or a concave shape.

[Second Embodiment] Next, a second embodiment according to the second invention will be described with reference to FIGS. 11 to 14.

As shown in FIGS. 11 and 12, the end mill of this embodiment has a blade portion 40 having a substantially polygonal cross section and a tapered shaft shape at the tip of a tool body (not shown). Four outer peripheral blades 42 are formed on the convex ridge line of the side surface 4I, and a cache 43 is formed at the tip of the blade portion 40 to recess toward the tool proximal end. Four bottom cutters 44 extending from the tip of each outer peripheral cutter 42 toward the tool rotation center PO are formed in the section.

Each of the peripheral blades 42 is formed as a so-called left-handed peripheral blade that twists counterclockwise around the tool axis O when the blade portion 40 is viewed from the front, and has a twist angle α (20°). Also, the taper angle φ of the peripheral cutter 42 is 1°30°.
is set to . Note that these torsion angle α and taper angle φ are determined as appropriate depending on the cutting conditions, etc. Specifically, the torsion angle α is 0° to 20°, and the taper angle φ is 30° to 5°.
It is said to be in the range of °.

On the other hand, when the blade section 40 is viewed from the front, the cache 43 is formed in a groove shape that extends radially from the tool center PO toward the side surface 41 between the outer peripheral blades 42 with each bottom blade 44 as a convex ridgeline part, and The center PO is provided so as to be retreated by a predetermined amount F from the leading edge of each peripheral cutter 42 toward the tool base end side. The wall surface of the cache 43 is composed of a rake face 45 that extends from each bottom cutter 44 toward the front in the tool rotation direction, and a relief 46 that extends from each bottom cutter 44 toward the rear in the tool rotation direction.

As shown in Figures 1I and 13, the scoop 45
The ridge line with the side surface 41 of the blade is formed into an inclined surface that extends toward the base end of the tool at a certain distance forward in the tool rotation direction from each peripheral cutter 42, so that the tip of the side surface 41 of the blade A scoop 47 having a predetermined width for each outer circumferential cutter 42 is formed in a portion on the forward side of the outer circumferential cutter 42 in the rotational direction.

Further, the clearance surface 46 with respect to the bottom blade 44 has a predetermined second clearance angle γl and a second clearance angle γ2 with respect to the bottom blade 44.
The blade side surface 41
A clearance surface 48 for each outer peripheral cutter 42 is formed in a portion on the rear side of the outer peripheral cutter 42 in the rotational direction at the tip end thereof.

Here, the above-mentioned scoop 4 is applied to the tip of each outer peripheral cutter 42.
The dip angle θ1 of No. 7 is set in the range of −30° to −50°. This is because when the rake angle θ1 exceeds 130° and deviates to the regular side, the cutting edge angle (θ
1+03) may be insufficient and chipping may easily occur. On the other hand, if the rake angle θl exceeds 150° and deviates to the negative angle side, the cutting resistance at the tip of the peripheral cutting edge 42 becomes excessively large, making it difficult to cut smoothly. This is because cutting may be hindered.

Furthermore, the clearance angle θ2 at the tip of the peripheral blade 42 is as follows:
It is set in the range of 20° to 35°.

If the deflection angle θ2 is less than 20°, abnormal wear may occur between the flank surface 48 and the workpiece, and the tip of the peripheral cutter 42 may wear out prematurely.On the other hand, if the deflection angle θ2 is 35°. This is because, if the angle exceeds 1, the cutting edge angle (θ1+03) at the tip of the peripheral blade 42 may become insufficient, which may cause problems such as chipping.

In addition, as shown in FIGS. 12 to 14, the bottom blade 44
The outer periphery of is notched at a predetermined chamfer angle C to prevent chips etc. during cutting. moreover,
The bottom blade 44 is formed so as to be inclined with a predetermined relief angle G toward the tool base end within a predetermined width H toward the tool rotation center PO side.

A portion of the blade side surface 41 closer to the tool base end than the tip end is an extension surface of each rake face 47 and flank face 48, so that the intermediate and base end portions of each peripheral cutter 42 are The same rake angle θI and relief angle θ2 as the above-mentioned tip portion are attached.

According to the end mill configured as described above, the blade portion 40 moves in the direction of arrow B (the first
1 and 12)), and
The blade portion 40 is sent forward in the axial direction, and the tip portions of the bottom blade 43 and the peripheral blade 42 perforate the workpiece, and then the intermediate portion and the base end portion of the peripheral blade 42 perforate the workpiece first. The diameter of the part that has been removed is expanded into a tapered shape. Then, after the blade portion 40 is fed out by a predetermined amount in the axial direction, the blade portion 40 is fed out in a direction perpendicular to the axial direction, thereby machining a Taber groove in the workpiece.

Here, according to the end mill of the present embodiment, the rake face 47 and the rake face 47 which are inclined at the rake angle θI and clearance angle θ2 in the above-mentioned ranges, and the rake face 47 which is inclined at the rake angle θI and clearance angle θ2 in the above-mentioned ranges, especially at the tip intersecting the cache 43 of the blade side surface 41. Because the surface 48 is provided, even when the blade part 40 is sent in the axial direction to machine the workpiece, chatter vibrations may occur due to insufficient cutting edge angle (θl+03), increase in cutting resistance, or early wear of the peripheral blade 42. As a result, there is no need to pre-process the workpiece material, improving cutting efficiency.

Note that in this embodiment, in particular, the portion of the blade side surface 41 other than the tip is also formed into an inclined surface that slopes at the same rake angles θ1 and θ2 as the tip, but the end mill of the present invention is not limited to this. Instead, the outer peripheral blades 42 may be formed into a planar shape in which the peripheral blades 42 are linearly connected, similar to a conventional end mill having a polygonal shape.

In short, a predetermined rake angle θl at the tip of the blade part 40
As long as the relief angle θ2 and the clearance angle θ2 are given, the shape of the other portions does not matter.

-Also, in this embodiment, the peripheral blade 42 is a left-handed twisted blade, but it is not limited to this; it can be changed to a straight blade, a right-handed screw, etc., and the number of peripheral blades 42 and bottom blades 44 is also four. It is not limited.

[Experimental Example] Next, in order to clarify the effects of the first invention and the second invention, the following 2N cutting test was conducted using the end mills according to each invention and the conventional end mill. .

(First cutting test) The end mill according to the first invention and the conventional end mill were used to finish the side surface of the workpiece as shown in FIG. 15, and the surface roughness of the cut surface was measured in each case. was measured and the cutting status was monitored.

The processing conditions at this time are as listed below, and the measurement results of surface roughness are shown in Table 1. The end mills used in the test had four, six, and eight peripheral blades, respectively, and their shapes and dimensions were the same except for the cross-sectional shape of the blade. Furthermore, the outer peripheral blades were all straight blades.

・Tool rotation diameter: 4mm ・Work material: 550G ・Cutting speed: 50 m/min.

・Tool feed ffl (F): 400mm/re
v.

- Width of cutting surface (W): 4 mm - Depth of cut (d): 0.05 mm (Second cutting test) Using the end mill according to the second invention and the conventional end mill, the results shown in Fig. 16 were obtained. Finish machining of the tapered groove was performed as shown in the figure below, and the cutting conditions at this time were compared. The processing conditions are as shown below, and the results are shown in Table 2.

・Workpiece material: 14PM 1 ・Groove shape: Depth (L) + 14mm : Tip width (W): 1mm : Taper angle (θ): 1° 30° Note that the cutting speed and tool feed amount are the same as in the first cutting above. Same as the test.

As is clear from Table 1, Table 1, and Table 1 below, when side milling is performed using a conventional end mill, if the number of teeth is small, the edge angle is insufficient and the edge strength deteriorates, resulting in chatter. Vibration occurs and deterioration of the finished surface roughness is unavoidable. Also, in order to avoid chatter, the number of blades has been increased and the cutting edge angle has been increased. -, the rake angle increases toward the negative angle side, cutting resistance increases, and smooth cutting cannot be performed. On the other hand, in the end mill according to the first aspect of the invention, the cutting edge angle can be set within a constant range regardless of the number of teeth, so chatter vibration does not occur, and the surface roughness of the finished surface during side machining is improved. Also, especially when the number of teeth is large, the rake angle tends to be more square than before.
The sharpness of the peripheral blade is improved and smooth cutting can be performed.

On the other hand, as is clear from Table 2, when machining a tapered groove with an end mill with a bottom blade, with a conventional end mill,
If the number of teeth is large, the rake angle at the tip of the peripheral edge will be too biased towards the negative angle side, cutting resistance will increase excessively, and the feed rate in the tool axis direction cannot be increased. On the other hand, in the end mill according to the second invention, the rake angle and stroke angle at the tip of the peripheral blade are set within a certain range regardless of the number of blades, so the tool can be used while avoiding chatter vibration and abnormal wear of the peripheral blade. It has become clear that the depth of cut in the axial direction can be increased by more than twice that of the conventional method.

In addition, in each of the above-mentioned cutting tests, it was also confirmed that the machining time was reduced to approximately I/10 compared to the case where the same machining was performed by electrical discharge machining.

[Effects of the Invention] As explained above, according to the first invention, the rake angle and clearance angle of the peripheral cutting edge are determined regardless of the number of teeth, and the rake angle is not excessively biased toward the negative angle side. The clearance angle is not insufficient, and the cutting edge angle is maintained at a constant jalit to ensure sufficient cutting edge strength, so it can be used for ff, h of high hardness materials such as molds.
Even during sharpening, chatter vibration and early wear of the peripheral blade are avoided, improving the quality of the finished surface.

Further, according to the second invention, similarly to the first invention, the rake angle and clearance angle of the peripheral cutting edge tip are set within appropriate ranges, and sufficient cutting edge strength is ensured, so that the tool can be moved in the axial direction. Even when cutting by feeding, the occurrence of chatter vibration and early wear of the tip of the peripheral blade are avoided, and as a result, there is no need for preliminary machining, especially when machining tapered grooves, and cutting efficiency is significantly improved.

[Brief explanation of drawings]

1 to 3 show an embodiment according to the first invention, in which FIG. 1 is a side view, FIG. 2 is a sectional view taken along line 1-1 in FIG. 4 to 10 are views showing modifications of the above embodiment; FIGS. 4 and 5 are views showing a case where there are three peripheral blades, and FIGS. The figure shows the case where there are four peripheral blades, Figure 7 shows the case where the peripheral blades are formed parallel to the tool axis, and Figure 8 shows the case where the peripheral blades are formed parallel to the tool axis.
The figure shows a case in which the peripheral blade is curved in an arc shape with respect to the tool axis, Figure 9 shows a case in which the peripheral blade is twisted, and Figure 10 shows the blade tip formed in a hemispherical shape. Figures 11 to 14 are diagrams showing an embodiment according to the second invention, in which Figure 11 is a side view, Figure 12 is a front view, and Figure 13 is a view of the tip of the peripheral blade. Front enlarged view, Figure 14 is a side enlarged view of the tip of the peripheral blade, Figure 15 is a diagram showing the machining form of the first cutting test, No. 6
The figure shows the machining form of the second cutting test, Figure 17 shows the groove shape of the workpiece, and Figures 18 and 19 show examples of conventional end mills. is a side view, and Fig. 19 is the ■ of Fig. 18.
It is a sectional view taken along the line -■. 11... Tool body, 13, 20, 30, 40,
...Blade part, 14, 20a, 30a, 40a...
·side,! 5, 22, 32, 47... Rake face, 16, 23, 33, 48... Relief face, I7.
21・3142・・・Peripheral blade, 43・・・・・・
Cash, 44...Bottom blade, PO...Tool rotation center, 0...Tool axis line.

Claims (2)

[Claims] (1) At the tip of the tool body (10), the tool axis (0)
In an end mill in which a blade part (13) is formed having a substantially polygonal cross section perpendicular to , and a peripheral blade (17) is formed at a ridgeline where each side surface (14) of this blade part (13) intersects, the above-mentioned Each side surface (14) of the blade part (13) is connected to each of the above-mentioned peripheral blades (
The rake face (15
) and a flank face (16) that extends rearward in the tool rotation direction from each peripheral cutter (17), and the rake face (15) in a cross section perpendicular to the axis (0) of the blade part (13).
An end mill characterized in that the rake angle (θ1) of the flank (θ1) is set in the range of -30° to -50°, and the clearance angle (θ2) of the flank face (16) in the cross section is set in the range of 20° to 35°. . (2) A blade part (40) whose cross section perpendicular to the axis (0) of the tool body has a substantially polygonal shape is formed at the tip of the tool body, and each side surface (40a) of this blade part (40) A peripheral blade (42) is formed at the intersecting ridgeline portion, and the blade portion (
40) A bottom cutter (44) extending from the tip of the peripheral cutter (42) toward the tool center (P0) is formed on the tip surface, and the tool tip surface between these bottom cutters (44) has a In an end mill in which a cache (43) is formed that is depressed toward the base end of the tool and opens on the side surface of the tip of the blade, the side surface of the blade divided by the cache (43) (
40a), the rake angle (θ1) of the side surface (47) extending from each peripheral blade (42) to the front side in the tool rotation direction when viewed from the front of the blade is in the range of -30° to -50°.
An end mill characterized in that a clearance angle (θ2) of the side surface (48) extending from 42) to the rear side in the tool rotation direction when viewed from the front of the blade is set in the range of 20° to 35°.