JP2003266231A - End mill and machining method and machine tool using end mill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end mill and a machining method and a machine tool employing the end mill capable of improving machining precision by more effectively improving rigidity of a tool system, prevention of the slanting of a tool and a work piece, and discharge ability of chips. <P>SOLUTION: An end mill 21A is formed that a cutting edge is formed facing the tip side of an end mill, the direction of a twist of the cutting edge is counterclockwise right hand cut left hand helix at the appearance from the end mill mounting side, and the twist angle of the cutting edge is a high twist of 50° or more. Or, an end mill 21B is formed that the cutting edge is formed facing the tip side of an end mill, and the direction of the twist of the cutting edge is clockwise left hand helix at the appearance from the end mill mounting side, and the twist angle of the cutting edge is a high twist of 50° ore more. The end mill 21A or the end mill 21B is attached to the main spindle of a machine tool to effect side machining or plunge machining of a work piece. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an end mill, a machining method using the same, and a machine tool.

[0002]

2. Description of the Related Art FIG. 5 shows the shape of a conventional general end mill. As shown in the figure, the end mill 10 has a cutting edge (outer peripheral edge) 1 attached to the outer periphery and a bottom edge 2 attached to the tip (lower edge in the figure). The cutting edge 1 of the end mill 10 is a twisting edge, and generally, a twisting angle θ of about 30 ° to 45 ° is the mainstream.

Further, the twist blade has left and right of the twist and left and right of the cutting edge. Normally, when the rotation direction is clockwise as viewed from the end mill mounting side (arrow A) as in the end mill 10A shown in FIG. 6 (a), the cutting edge 1 is twisted clockwise (right twist). The blade 1 is attached upward (toward the end mill mounting side) (right blade right twist). Conversely, when the rotation direction is counterclockwise when viewed from the endmill mounting side (arrow B) as in the end mill 10A shown in FIG. 6B, the twisting direction of the cutting edge 1 is counterclockwise (left twist). Yes, the cutting edge 1 is attached upward (toward the end mill mounting side) (left blade left twist).

Further, as shown in FIG. 7, the cutting edge 1 faces downward (toward the end mill tip side), and the twisting direction of this cutting edge 1 is counterclockwise (left twist) when viewed from the end mill mounting side. End mill 10 with right blade left twist,
Although not shown, there is also a left-blade right-handed end mill in which the cutting edge is attached downward (toward the tip side) and the twisting direction of this cutting edge is clockwise (right-handed) when viewed from the end mill mounting side. . That is, there are a total of four types of end mills, which are combinations of left and right twists and left and right cutting edges. As a method of attaching these end mills, as shown in the example of the end mill 10A in FIG. 8, the attachment side of the end mill 10A is attached to the spindle 6 of the machine tool via the collet 4 and the holder 5.

[0005]

However, when a workpiece is machined by using the conventional end mills 10A and 10B having a right-handed right blade and a left-handed left blade as shown in FIG. 6, the following problems occur. is there.

That is, as shown in FIG. 6 (a), in the end mill 10A, the cutting resistance F is divided into an axial resistance fa of the end mill 10 and a radial resistance fr of the end mill 10, and the cutting resistance F is divided into the above-mentioned shafts respectively. Direction and the radial direction. The axial resistance fa at this time works downward (toward the end mill tip side). When viewed three-dimensionally, the resistance fr in the radial direction is divided into a resistance ft in the tangential direction and a resistance fn perpendicular thereto, but here, for convenience, the resultant force thereof is fr. Further, even with the end mill 10A shown in FIG. 6B, the cutting edge 1
Is in the upward direction, the direction of the resistance fa in the axial direction is the same as in the case of the end mill 10A (downward from the end mill).

Therefore, any of the end mills 10 shown in FIG.
A and 10B also have an axial resistance fa of end mills 10A,
Since 10B acts in the direction (arrow d2 direction) of pulling out 10B from the machine tool spindle 6 (see FIG. 8), the contact pressure of the contact portion 7 between the machine tool spindle 5 and the tool system shown in FIG. Stiffness may decrease and chatter may occur. Further, the resistance fr in the radial direction causes deformation (tilt) of the tool (end mill) or the workpiece, which deteriorates the machining accuracy. This is the same even when a two-face restraint type shank is used for mounting the end mill. Further, since the chip discharging direction c at this time is upward (toward the end mill mounting side), the end mill 1 can be mounted on a vertical machine tool.
When 0A and 10B are attached to perform side surface machining of a work piece, chips tend to be deposited on the work piece, which causes thermal deformation of the work piece and biting of the tool into the machined part. Defects are likely to occur.

Particularly in the field of machining in recent years, there is a demand for higher efficiency and higher precision of machining, and therefore, the end mill 10 having a right-handed right-handed blade and a left-handed left-handed helix as shown in FIG.
If A and 10B are used as they are, the problems such as the reduction of the rigidity of the tool system due to the cutting resistance, the deformation of the tool / workpiece, the thermal deformation due to the chips, and the chipping of the tool due to the chips being caught become more serious. ing.

On the other hand, when the right-handed left-handed end mill 10 as shown in FIG. 7 or the left-handed right-handed end mill (not shown) is used, the direction of the cutting resistance (axial resistance) and chip Since the discharge direction is opposite to that of the end mills 10A and 10B having the right-handed right blade and the left-handed left blade shown in FIG. 6, the above problems can be alleviated.
Not enough (details below).

Therefore, in view of the above circumstances, the present invention more effectively improves the rigidity of the tool system and prevents the tool / workpiece from falling.
An object of the present invention is to provide an end mill capable of improving machining accuracy by improving the chip discharging property, a machining method using the same, and a machine tool.

[0011]

[Means for Solving the Problems] First to solve the above problems
In the end mill of the invention, the cutting edge is directed toward the tip side of the end mill, the twisting direction of this cutting edge is a right-handed left-handed helix counterclockwise when viewed from the end-mill mounting side, and the helix angle of the cutting edge is 50. It is characterized by a strong twist of more than °.

Further, in the end mill of the second invention, the cutting edge is directed toward the tip side of the end mill, and the twisting direction of this cutting edge is a left-handed right-handed twist clockwise as viewed from the end mill mounting side, and The blade is characterized by a strong twist with a twist angle of 50 ° or more.

Further, the machining method of the third invention uses the end mill of the first or second invention, and feeds the end mill in the radial direction of the end mill along the machining surface of the workpiece to thereby machine the machining surface. Characterized by processing.

In the machining method of the fourth invention, the end mill according to claim 1 or 2 is used, and plunge machining is performed by feeding the end mill along the machining surface of the workpiece in the axial direction of the end mill. The machined surface is machined by

Further, the machine tool of the fifth invention is characterized in that the end mill of the first or second invention is attached to a spindle and the end mill is rotationally driven by the spindle to machine a workpiece.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a configuration diagram of an end mill according to an embodiment of the present invention, FIG. 2 is a configuration diagram of essential parts of a machine tool having the end mill, and FIG. 3 is a helix angle of a cutting edge of the end mill and a cutting resistance ratio. FIG. 4 is a characteristic diagram showing a relationship with fa / fr, and FIG. 4 is an explanatory diagram of a processing method using the end mill.

The end mills 21A and 21B shown in FIG.
It has a cutting edge (peripheral edge) 22 attached to the outer periphery and a bottom edge 23 attached to the tip (lower edge in the figure). Incidentally, reference numeral 24 in the drawing is a flank of the cutting edge 22.

In the end mill 21A shown in FIG. 1 (a), the cutting edge 22 is directed downward (toward the end mill tip side), and the twisting direction of the cutting edge 22 is counterclockwise (left twist) when viewed from the end mill mounting side. It is an end mill with a right blade and left twist. The rotation direction of this end mill 21A is
It is clockwise as seen from the side where the end mill is attached, as indicated by arrow A. On the other hand, in the end mill 21B shown in FIG. 1B, the cutting edge 22 is directed downward (toward the end mill tip side), and the twisting direction of the cutting edge 22 is clockwise (right twist) when viewed from the end mill mounting side. It is an end mill with a right-handed blade. The rotation direction of the end mill 21B is counterclockwise when viewed from the end mill mounting side as indicated by arrow B.

As shown in FIG. 2A, the end mill 21
A is attached to a spindle 33 of a machine tool via a collet 31 and a holder 32 of a fixture, and is rotated counterclockwise by the spindle 33 as indicated by arrow A. Figure 2
As shown in (b), the end mill 21B includes a spindle 3 of a machine tool via a collet 31 and a holder 32 of a fixture.
3, and is driven to rotate clockwise by the main shaft 33 as indicated by arrow B.

Therefore, whichever end mill 21A, 21B
However, when the work piece is attached to the spindle 33 of the machine tool to process the work piece, as shown in FIG.
The direction of the axial resistance fa of 1B is upward (toward the end mill mounting side). Therefore, the axial resistance fa acts so as to press the end mills 21A and 21B against the spindle 33 of the machine tool (arrow d1 direction), and the contact portion 34 between the spindle 33 of the machine tool and the tool system shown in FIG. The contact surface pressure increases, which is advantageous in terms of mounting rigidity. Further, by setting the cutting edge 22 downward (toward the tip of the end mill), the chip discharge direction c is also downward (toward the tip of the end mill). For this reason, especially when the end mills 21A and 21B are attached to a vertical machine tool to perform the side surface machining of the workpiece, the chips fall downward and the accumulation of the chips is prevented. It is possible to prevent the tool from being damaged due to deformation or biting of chips into the machined portion.

In the present embodiment, the end mill 21 is provided in order to secure the above-described effects and the like.
The cutting edges 22 of A and 21B are strong helix blades with a helix angle θ of 50 ° or more. As a result, in the end mills 21A and 21B of the present embodiment, the conventional end mill with right-handed left-handed or left-handed right-handed twist (twist angle θ = 30 ° to
45 °), the resistance fa in the axial direction becomes larger and the resistance fr in the radial direction becomes smaller.

Here, the twist θ of the cutting edge 22 is set to 50 ° or more because the twist angle θ of the cutting edge shown in FIG. 3 and the ratio fa / fr of the resistances fa and fr in the axial direction and the radial direction (actual measurement Value). That is, as shown in FIG. 3, when the twist angle θ of the cutting edge is about 50 ° or less, the resistance ratio fa
/ Fr gradually increases linearly, but when the twist angle θ of the cutting edge becomes about 50 ° or more, the resistance ratio fa / f rapidly increases.
This is because, since r increases, by setting the twist angle θ of the cutting edge to 50 ° or more, the axial resistance fa can be more effectively predominantly (increased).

Thus, the end mill 21 of this embodiment is
In A and 21B, the left blade has a left twist or the left blade has a right twist,
In addition, by setting the helix angle θ of the cutting edge 22 to be a strong helix of 50 ° or more, upward (toward the end mill mounting side)
Since the axial resistance fa that acts on (1) is dominantly (increased), the force for pressing the end mills 21A and 21B against the spindle 33 of the machine tool becomes extremely large, which is very advantageous in terms of mounting rigidity. Moreover, the axial resistance fa
Therefore, since the radial resistance fr of the end mills 21A and 21B becomes small, the tool (end mill) or the work (deformation) of the tool (end mill) due to the radial resistance fr can be prevented. The effect of preventing the tool / workpiece from collapsing is particularly effective when machining a thin wall of the workpiece. In addition to these effects, the chip discharge direction c is downward (toward the end mill tip side) as described above, so that the thermal deformation of the workpiece due to the chips and the cutting of the tool into the machined part The effect of preventing loss can also be obtained.

Based on FIG. 4, the end mills 21A,
A processing method using 21B will be described. Note that FIG.
Although only the end mill 21A is shown in FIG. 7, the same effect can be obtained with the same processing method as in the case of the end mill 21A, though the rotation direction of the end mill 21B is opposite.

FIG. 4 (a) shows a side surface processing, in which the end mill 21A is rotated counterclockwise as shown by an arrow A,
The side surface 35a of the workpiece is machined by feeding the workpiece 35 along the side surface (machining surface) 35a of the end mill 21A in the radial direction (cutting feed direction D1). In this case, the above effects can be expected.

Further, as shown in FIG. 4B, the side surface (working surface) 35a of the workpiece 35 is plunged. That is, while the end mill 21A is being machine-fed in the axial direction (cutting feed direction D1 and rapid feed direction D2) of the end mill 21A along the workpiece side surface 35a, the end mill 2
The side surface 35a of the workpiece is machined while being pick-fed in the radial direction of 1A (pick-feed direction D4). In this case, since the machining feed direction is the axial direction of the end mill 21A, the axial resistance fa becomes more dominant, so that the deformation (tilt) of the tool (end mill) or the workpiece is further reduced. Furthermore, in the case of plunge machining, the machining action mainly acts on the tip portion of the end mill 21A (bottom blade 23
And the cutting edge 22), the cutting edge 22 may be formed only near the tip as shown in FIG. 4C. However, in this case, the mounting side portion 21 without the cutting edge 22
In order to avoid friction with the work, A-1 needs to have a smaller diameter than the portion where the cutting edge 22 is formed.

As described above, according to the present embodiment, the right blade has a left twist or the left blade has a right twist, and the twist angle θ is 50 °.
By using the end mills 21A and 21B having a strong twist as described above, it is possible to more effectively improve the mounting rigidity of the tool system, prevent deformation (tilt) of the tool / workpiece, and improve chip evacuation. This can improve the processing accuracy. Especially when machining thin walls, it is effective in terms of deformation (tilting) of tools and workpieces.

As the end mill to which the present invention is applied, there are a square end mill, a ball end mill, a radius end mill, a taper end mill, a roughing end mill and the like.

[0030]

As described above in detail with the embodiments of the invention, in the end mill of the first invention, the cutting edge is directed toward the tip side of the end mill, and the twisting direction of this cutting edge is from the end mill mounting side. The right blade has a left-handed twist in a counterclockwise direction, and the cutting edge has a helix angle of 50 ° or more.

In the end mill according to the second aspect of the invention, the cutting edge is directed toward the tip side of the end mill, and the twisting direction of this cutting edge is a left-handed right-handed twist clockwise as viewed from the end mill mounting side, and The blade is characterized by a strong twist with a twist angle of 50 ° or more.

Therefore, according to the end mill of the first or second invention, by using the end mill having the right-handed left-handed or left-handed right-handed helix and the helix angle of 50 ° or more, the tool can be more effectively used. It is possible to improve the mounting rigidity of the system, prevent deformation (tilt) of tools and workpieces, and improve chip evacuation, thereby improving machining accuracy. Especially when machining thin walls, it is effective in terms of deformation (tilting) of tools and workpieces.

Further, the machining method of the third invention uses the end mill of the first or second invention, and feeds the end mill in the radial direction of the end mill along the machining surface (side surface) of the workpiece, whereby It is characterized in that the machined surface is machined.

Therefore, according to the processing method of the third invention, the above effects can be expected. That is, it is possible to more effectively improve the mounting rigidity of the tool system, prevent deformation (tilt) of the tool / workpiece, and improve chip evacuation, thereby improving machining accuracy. Especially when machining thin walls, it is effective in terms of deformation (tilting) of tools and workpieces.

In the machining method of the fourth invention, the end mill according to claim 1 or 2 is used, and plunge machining is performed by feeding the end mill along the machining surface of the workpiece in the axial direction of the end mill. The machined surface is machined by

Therefore, according to the machining method of the fourth invention, since the machining feed direction is the axial direction of the end mill, the axial resistance becomes more dominant, so that the deformation of the tool (end mill) or the work piece. (Collapse) is further reduced. Further, in the case of plunge machining, the cutting action is mainly performed at the tip portion of the end mill (the intersection point of the bottom blade and the cutting edge), so the cutting edge may be formed only near the tip.

The machine tool of the fifth aspect of the invention is characterized in that the end mill of the first or second aspect of the invention is attached to a spindle and the end mill is rotationally driven by the spindle to machine a workpiece.

Therefore, according to the machine tool of the fifth aspect of the present invention, by providing the end mill of the first aspect or the first aspect of the invention, the above effect, that is, the mounting rigidity of the tool system and the tool It is possible to prevent deformation (tilt) of the work piece and to improve the chip evacuation property, thereby improving the machining accuracy. Therefore, the machine tool has higher performance.

[Brief description of drawings]

FIG. 1 is a diagram showing a shape of an end mill according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a main part of a machine tool including the end mill (a diagram showing a method of holding an end mill when a 7/24 taper BT shank is used).

FIG. 3 is a characteristic diagram showing a relationship between a helix angle of a cutting edge of the end mill and a cutting resistance ratio fa / fr.

FIG. 4 is an explanatory diagram of a processing method using the end mill.

FIG. 5 is a view showing a shape of a conventional general end mill.

FIG. 6 is a view showing a shape of a conventional end mill with right-handed right-handed helix and left-handed left-handed helix.

FIG. 7 is a diagram showing a shape of a conventional left-handed left-handed end mill.

FIG. 8 is a diagram showing an end mill holding method when a 7/24 taper BT shank is used.

[Explanation of symbols]

21A end mill 21B end mill 22 cutting edge 23 Bottom blade 24 flank 31 Collet 32 holder 33 spindle 34 contact area 35 Workpiece 35a side surface θ twist angle A rotation direction (counterclockwise) B rotation direction (clockwise) F Cutting resistance fa Axial resistance fr Radial resistance c Chip ejection direction D1 Cutting feed direction D2 Cutting feed direction D3 Fast-forward direction D4 Pick feed direction

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masato Kinouchi             4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City, Hiroshima Prefecture               Mitsubishi Heavy Industries Ltd. Hiroshima Research Center F-term (reference) 3C022 KK03 KK06 KK16 KK23 KK28                       PP00

Claims (5)

[Claims] 1. A cutting edge is attached to the tip side of the end mill,
An end mill characterized in that the twisting direction of the cutting edge is a left-handed right-handed blade twisting counterclockwise when viewed from the end-mill mounting side, and the twisting angle of the cutting edge is a strong twist of 50 ° or more. 2. A cutting edge is attached to the end side of the end mill,
An end mill characterized in that the twisting direction of the cutting edge is a left-handed right-handed twist clockwise when viewed from the end mill mounting side, and the helix angle of the cutting edge is a strong twist of 50 ° or more. 3. The end mill according to claim 1 or 2, wherein the end mill is machined and fed in a radial direction of the end mill along a work surface of a workpiece to machine the work surface. Processing method. 4. The end mill according to claim 1 or 2 is used, and the end face is machined by performing plunge machining in which the end mill is machined in the axial direction of the end mill along the work surface of the workpiece. A processing method characterized by the above. 5. A machine tool, wherein the end mill according to claim 1 or 2 is attached to a main shaft, and the end mill is rotationally driven by the main shaft to machine a workpiece.