Tip replaceable cutting tool and method of turning

Abstract

To provide a tip replaceable cutting tool for grooving that can provide highly efficient processing on outside diameter processing.SOLUTION: A tip replaceable cutting tool includes: a holder including a head member including an insert attachment seat to which a cutting insert is attached, a holder body to which the head member is mounted, and a drive mechanism for rotating the holder body about a rotational axis to change the posture of the cutting insert; and a rod-like grooving cutting insert that is held to the head member of the holder. The head member includes a pair of jaw parts for gripping the cutting insert and is fixed to the holder body in a posture where a direction in which the pair of jaw parts face each other becomes parallel to the rotational axis of the holder body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an indexable cutting tool and a turning method. [Background technology]

[0002] BACKGROUND ART Indexable cutting tools used for grooving the end face of a cylindrical workpiece have been known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-168044 Summary of the Invention [Problem to be solved by the invention]

[0004] By using a cutting insert that combines the breaker areas for both grooving and turning, cutting tools for grooving can be used for external diameter machining, as shown on the right side of Figure 10, in addition to grooving, as shown on the left side of Figure 10. The indexable cutting tool 100 shown in Fig. 10 includes a holder 111, a head member 112 attached to the tip of the holder 111, and a cutting insert 150 clamped to the head member 112. Fig. 11 is an enlarged view of the rake face of the cutting insert 150.

[0005] However, conventional cutting tools for grooving have not been able to perform highly efficient outer diameter machining for the following reasons. First, in the outer diameter machining shown on the right side of Fig. 10, the advancing direction of the cutting insert 150 (the horizontal direction in the figure) does not coincide with the clamping direction of the cutting insert 150 by the head member 112. There is a risk that the clamping position of the cutting insert 150 may be shifted due to the cutting load, and therefore machining conditions that apply a large load could not be set. Furthermore, since the direction of the principal component of force during outer diameter machining (the horizontal direction in the figure) and the longitudinal direction of the holder 111 (the vertical direction in the figure) are perpendicular to each other, chattering is likely to occur during machining. 11, the breaker region 151 used in outer diameter machining is narrower than the breaker region 152 used in grooving. This makes it difficult to process thick chips during high feed machining.

[0006] An object of the present invention is to provide an indexable cutting tool for grooving that is capable of highly efficient machining even in external diameter machining. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided an indexable cutting tool comprising: a holder including a head member having an insert mounting seat for mounting a cutting insert, a holder body to which the head member is attached, and a drive mechanism for rotating the holder body about a rotation axis to change the attitude of the cutting insert; and a rod-shaped cutting insert for groove machining held by the head member of the holder. The head member has a pair of jaws for gripping the cutting insert, and is fixed to the holder body in an attitude in which the directions in which the pair of jaws face each other are parallel to the rotation axis of the holder body.

[0008] According to this configuration, by operating the drive mechanism, the holder body can be rotated, and the arrangement angle of the rod-shaped cutting insert can be freely adjusted. Because the holder body is rotatable, in external diameter machining, the extension direction of the cutting insert can be aligned along the outer peripheral surface of the workpiece, and external diameter machining can be performed using the cutting edge located at the end of the extension direction (longitudinal direction) of the rod-shaped cutting insert. Since external diameter machining is performed while moving the cutting insert in the longitudinal direction, the load during machining can be supported by the thick portion of the head member that supports the cutting insert. High-efficiency external diameter machining is possible under conditions where a large load is applied.

[0009] The cutting insert may have a rake face located on the side of the end of the cutting insert, a flank face connected to the rake face and located on the tip face of the cutting insert, and a cutting edge located on the intersecting ridge between the rake face and the flank face, and the cutting insert may be configured to be held in the head member with the rake face facing toward the tip side in a direction along the rotation axis of the holder body.

[0010] According to one aspect of the present invention, there is provided a turning method, in which the indexable cutting tool is placed on a cylindrical workpiece extending along a central axis in an orientation in which the rotation axis of the holder body is perpendicular to the central axis of the workpiece, and the outer diameter of the workpiece is machined within the range of 90°<θ≦180°, where θ is the angle formed between the extension direction of the cutting insert and the central axis of the workpiece.

[0011] The method may also be a method for machining the outer diameter of the workpiece when the angle θ is in the range of 110°≦θ≦140°. [Effects of the Invention]

[0012] According to one aspect of the present invention, there are provided an indexable cutting tool for grooving that is capable of highly efficient machining even in external diameter machining, and a turning method using the same. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a partial perspective view of an indexable cutting tool according to an embodiment. [Figure 2] FIG. 2 is a front view of the indexable cutting tool according to the embodiment. [Figure 3] FIG. 3 is a partial perspective view of the indexable cutting tool according to the embodiment. [Figure 4] FIG. 4 is a perspective view for explaining grooving using the indexable cutting tool of the embodiment. [Figure 5] FIG. 5 is a side view for explaining grooving using the indexable cutting tool of the embodiment. [Figure 6]FIG. 6 is a perspective view for explaining outer diameter machining using the indexable cutting tool of the embodiment. [Figure 7] FIG. 7 is a side view for explaining outer diameter machining using the indexable cutting tool of the embodiment. [Figure 8] FIG. 8 is a perspective view for explaining another example of outer diameter machining using the indexable cutting tool of the embodiment. [Figure 9] FIG. 9 is a side view for explaining another example of outer diameter machining using the indexable cutting tool of the embodiment. [Figure 10] FIG. 10 is an explanatory diagram of a machining method using a conventional indexable cutting tool. [Figure 11] FIG. 11 is an enlarged view of the rake face of the cutting insert. DETAILED DESCRIPTION OF THE INVENTION

[0014] (Indexable cutting tools) Fig. 1 is a partial perspective view of an indexable cutting tool according to an embodiment, Fig. 2 is a front view of the indexable cutting tool according to an embodiment, and Fig. 3 is a partial perspective view of the indexable cutting tool according to an embodiment.

[0015] The indexable cutting tool 1 of this embodiment is an indexable cutting tool used in turning, and is detachably mounted on a tool post or the like of a machine tool such as a lathe (not shown). In this embodiment, the indexable cutting tool 1 and the cutting insert 2 may be simply referred to as a cutting tool or a tool.

[0016] As shown in FIGS. 1 to 3 , an indexable cutting tool 1 includes a cutting insert 2 having a cutting portion 20 and a holder 3 that holds the cutting insert 2. As will be described in detail later, the cutting portion 20 has a cutting edge 21, a rake face 22, and a flank 23. The holder 3 also includes a holder body 31 that is attached to a tool post or the like of a machine tool, a head member 32 that clamps and fixes the cutting insert 2, a drive mechanism 50 that rotates the holder body 31 about a rotation axis C, and a fastening screw 11 that fixes the head member 32 to the holder body 31. The head member 32 is detachably attached to the first end 31a of the holder body 31, which has two ends (a first end 31a and a second end 31b) in the extension direction. The cutting insert 2 is held by the head member 32 with the rake face 22 of the cutting portion 20 facing the tip side.

[0017] In this embodiment, the rotation axis C shown in FIGS. 1 to 3 coincides with the tool center axis of the holder body 31. The holder 3 has a longitudinal shape in the direction in which the rotation axis C extends. The rotation axis C corresponds to the tool axis of the indexable cutting tool 1. In the direction in which the rotation axis C extends, the direction from the second end 31b of the holder body 31 to the first end 31a where the head member 32 is disposed (+X side) is called the front end side, and the direction from the first end 31a to the second end 31b (-X side) is called the rear end side.

[0018] The holder body 31 is made of a metal such as steel. The holder body 31 is cylindrical overall. A head mounting portion 31c to which the head member 32 is attached is provided at a first end portion 31a of the holder body 31. The head mounting portion 31c is a recess that is machined to match the shape of the head member 32. The head mounting portion 31c opens on the side surface and tip surface of the holder body 31.

[0019] The head member 32 is made of metal. The head member 32 is formed by, for example, casting or machining. The head member 32 is fastened and fixed to the first end 31a, i.e., the tip, of the holder main body 31 by a fastening screw 11. The fastening screw 11 is screwed into a female thread (not shown) provided on the tip surface 31d of the holder main body 31. The fastening screw 11 presses the tip surface of the head member 32 in the axial direction with its screw head, fixing the head member 32 to the head mounting portion 31c.

[0020] The head member 32 has a plate-shaped head main body 33 and a plate-shaped head fixing plate 34 extending from the head main body 33 to the left.

[0021] The head body 33 is plate-shaped and extends along a plane parallel to the rotation axis C. A portion of the head body 33 is disposed within a recess in the head mounting portion 31c. The head body 33 protrudes from the mounting position on the holder body 31 in the tangent direction of a circle centered on the rotation axis C. The protruding direction of the head body 33 relative to the holder body 31 is referred to as the head protruding direction H shown in Figures 1 to 3. In the head protruding direction H, the direction away from the head mounting portion 31c (+H direction) is referred to as the leading end side of the head protruding direction H, and the direction approaching the head mounting portion 31c (-H direction) is referred to as the trailing end side of the head protruding direction.

[0022] The head body 33 has a pair of jaw portions 36 spaced apart from each other in the direction along the rotation axis C, an insert mounting seat 35 located between the pair of opposing jaw portions 36 and on which the cutting insert 2 is placed, a relief portion 37 located between the pair of jaw portions 36 and provided on the rear end side of the insert mounting seat 35 in the head protruding direction H, and a connecting portion 38 located on the rear end side of the relief portion 37 in the head protruding direction H and elastically connecting the pair of jaw portions 36 to each other.

[0023] The pair of jaw portions 36 face each other in a direction parallel to the rotation axis C and constitute the insert mounting seat 35. The pair of jaw portions 36 each come into contact with a side surface of the cutting insert 2 placed in the insert mounting seat 35. Of the pair of jaw portions 36, one jaw portion 36 located on the leading end side in the direction along the rotation axis C is the upper jaw portion 36A, and the other jaw portion 36 located on the rear end side in the direction along the rotation axis C is the lower jaw portion 36B.

[0024] The insert mounting seat 35 is located at the tip end portion of the head main body 33 in the head protruding direction H. The tip end of the lower jaw portion 36B is located at the position in the holder 3 that is radially farthest from the rotation axis C. In addition, in the direction along the rotation axis C, the insert mounting seat 35 is located at the tip end of the holder 3.

[0025] The insert mounting seat 35 penetrates the head body 33 in the plate thickness direction and extends along the head protruding direction H. The insert mounting seat 35 opens toward the tip side in the head protruding direction H. The cutting insert 2 is removably attached to the insert mounting seat 35.

[0026] The insert mounting seat 35 has a pressing surface 35a that contacts the upper surface (pressed surface 25a) of the holding portion 25 of the cutting insert 2 described later, a base surface 35b that contacts the lower surface (seating surface 25b) of the holding portion 25 of the cutting insert 2, and an abutment surface 35c that contacts the end surface facing the rear end side of the cutting insert 2.

[0027] The pressing surface 35a is disposed on the surface of the upper jaw 36A facing the lower jaw 36B. The seat surface 35b is disposed on the surface of the lower jaw 36B facing the upper jaw 36A. The pressing surface 35a and the seat surface 35b sandwich and press the cutting insert 2 in the direction along the rotation axis C.

[0028] The abutment surface 35c is disposed at the rear end of the insert mounting seat 35 in the head protruding direction H. The abutment surface 35c is flat and faces the tip side in the head protruding direction H. The abutment surface 35c comes into contact with the end face of the cutting insert 2 disposed in the insert mounting seat 35, and supports the cutting insert 2 from the rear end side in the head protruding direction H.

[0029] The relief portion 37 is disposed on the rear end side of the insert mounting seat 35 in the head protruding direction H, and is in communication with the insert mounting seat 35. The relief portion 37 is in the form of a slit that penetrates the head body 33 in the plate thickness direction. The relief portion 37 is a gap that accommodates the cutting portion 20 of the unused side of the cutting insert 2 located at the rear end of the insert mounting seat 35 in the head protruding direction H.

[0030] The connecting portion 38 is disposed on the rear end side of the relief portion 37. The connecting portion 38 is located at the rear end side portion of the head main body 33 in the head protruding direction H, and connects an upper portion including the upper jaw portion 36A and a lower portion including the lower jaw portion 36B of the head main body 33. The connecting portion 38 is elastically deformable. The elastic deformation of the connecting portion 38 changes the distance between the pressing surface 35a of the upper jaw portion 36A and the seat surface 35b of the lower jaw portion 36B.

[0031] When the fastening screw 11 is screwed in with the cutting insert 2 placed in the insert mounting seat 35, the upper jaw 36A is displaced downward while the connecting portion 38 is elastically deformed by the pressure of the fastening screw 11. This narrows the gap between the upper jaw 36A and the lower jaw 36B, and the holding portion 25 of the cutting insert 2 placed in the insert mounting seat 35 is clamped between the pressing surface 35a of the upper jaw 36A and the seat surface 35b of the lower jaw 36B.

[0032] Furthermore, by loosening the fastening screw 11, the fastening screw 11 rises, and the connecting portion 38 undergoes restoration deformation, displacing the upper jaw portion 36A in a direction away from the lower jaw portion 36B, thereby releasing the clamped state of the holding portion 25 by the insert mounting seat 35. This allows the cutting insert 2 to be extracted from the insert mounting seat 35.

[0033] The head fixing plate 34 protrudes in a direction perpendicular to the head body 33 from the surface of the head body 33, where the lower jaw 36B is provided, facing the holder body 31. The head fixing plate 34 is plate-shaped and extends along a plane parallel to the rotation axis C. One plate surface of the head fixing plate 34 comes into contact with a flat surface provided at the tip of the holder body 31. The head fixing plate 34 may be fixed to the side of the holder body 31 with a screw.

[0034] The cutting insert 2 is a rod-shaped cutting insert extending along an insert central axis (not shown). In this embodiment, the cutting insert 2 has a polygonal columnar shape, more specifically, a substantially quadrangular columnar shape (see FIGS. 1 to 3). In this embodiment, the insert central axis of the cutting insert extends along the head protruding direction H and is perpendicular to the rotation axis C (tool central axis) of the holder 3.

[0035] The cutting insert 2 is inserted into the insert mounting seat 35 of the head member 32 from the tip side in the head protruding direction H, and is removably attached to the insert mounting seat 35. The cutting insert 2 includes a rectangular pillar-shaped holding portion 25 and a pair of cutting portions 20 located at both ends of the holding portion 25 in the longitudinal direction.

[0036] That is, the cutting insert 2 of this embodiment is a so-called dog-bone type insert in which the cutting edges 21 at both ends (two corners) of the cutting insert 2 in the longitudinal direction can be used. The cutting portion 20 has a rake face 22 facing in one direction perpendicular to the longitudinal direction of the cutting insert 2, a flank face 23 consisting of two side surfaces adjacent to the rake face 22 and the tip face of the cutting insert 2, and a cutting edge 21 disposed on a ridge line portion connecting the rake face 22 and the flank face 23. The cutting insert 2 is attached to the insert mounting seat 35 of the head member 32 with the rake face 22 facing the tip side of the rotation axis C.

[0037] The drive mechanism 50 is connected to the rear end of the holder body 31 in the direction along the rotation axis C. The drive mechanism 50 includes, for example, a servo motor and a control device that controls the rotation angle of the servo motor's main shaft. The drive mechanism 50 rotates the holder body 31 around the rotation axis C. This allows the indexable cutting tool 1 to change the arrangement angle of the cutting insert 2 relative to the tool post of the machine tool that holds the holder 3. In other words, the indexable cutting tool 1 can change the arrangement angle of the cutting insert 2 relative to the workpiece.

[0038] (Turning method) Hereinafter, a turning method using the indexable cutting tool 1 will be described with reference to FIGS.

[0039] [Grooving] FIG. 4 is a perspective view for explaining grooving using the indexable cutting tool 1, and FIG. 5 is a side view of the same.

[0040] When performing grooving using the indexable cutting tool 1, as shown in Figures 4 and 5, the indexable cutting tool 1 is placed relative to a cylindrical workpiece W extending along a central axis O in an orientation in which the rotation axis C of the holder body 31 is perpendicular to the central axis O of the workpiece W. As a result, the cutting insert 2 is placed in an orientation in which it extends in a direction perpendicular to the central axis O of the workpiece W. At this time, the angle θ between the extension direction (longitudinal direction) of the cutting insert 2 and the central axis O of the workpiece W is 90°.

[0041] With the indexable cutting tool 1 and workpiece W positioned as described above, the workpiece W is rotated around its central axis O while the cutting insert 2 is moved toward the central axis O of the workpiece W, thereby forming a groove extending circumferentially around the central axis O on the outer surface of the workpiece W.

[0042] [Outer diameter machining] FIG. 6 is a perspective view for explaining outer diameter machining using the indexable cutting tool 1, and FIG. 7 is a side view of the same.

[0043] Next, when performing external diameter machining using the indexable cutting tool 1, the drive mechanism 50 shown in FIG. 1 is operated to rotate the holder body 31 by 90° around the rotation axis C. Then, as shown in FIGS. 6 and 7, the indexable cutting tool 1 is placed relative to a cylindrical workpiece W extending along a central axis O, with the rotation axis C of the holder body 31 perpendicular to the central axis O of the workpiece W. As a result, the cutting insert 2 is placed in a position along the outer peripheral surface of the workpiece W, parallel to the central axis O of the workpiece W. At this time, the angle θ formed between the extension direction (longitudinal direction) of the cutting insert 2 and the central axis O of the workpiece W is 180°.

[0044] With the indexable cutting tool 1 and workpiece W positioned as described above, the workpiece W can be rotated around its central axis O while the cutting insert 2 is moved parallel to the central axis O of the workpiece W, thereby turning the outer peripheral surface from the end of the workpiece W in the direction of the central axis O, thereby machining the outer diameter of the workpiece W.

[0045] According to the machining method using the indexable cutting tool 1 described above, the holder body 31 is rotated around the rotation axis C by the drive mechanism 50, thereby changing the attitude of the cutting insert 2 relative to the workpiece W. As a result, in machining the outer diameter of the workpiece W, the workpiece W can be turned using the cutting edge 21 of the cutting insert 2 that is located at the tip in the longitudinal direction. According to the above-described machining method, the rear end surface of the cutting insert 2 is supported by the abutment surface 35c in the direction of travel of the cutting insert 2 during outer diameter machining (horizontal direction in Figure 7), so even if machining is performed under conditions that apply a large load, the cutting insert 2 will not shift from the clamped position. In addition, the breaker area 26 of the cutting insert 2 that acts during external diameter machining is the same as the breaker area 26 that acts during grooving shown in Figure 5. Therefore, even when machining is performed under high feed conditions that generate thick chips, the wide breaker area 26 in the center of the rake face 22 can efficiently discharge the chips. Furthermore, since the direction of the principal force during outer diameter machining (the direction toward the back of the paper in Figure 7) is parallel to the central axis (rotation axis C) of the holder 3 of the indexable cutting tool 1, vibration is less likely to occur during machining. In this way, according to the machining method using the indexable cutting tool 1, the outer diameter of the workpiece W can be machined with high efficiency.

[0046] Since the holder body 31 of the indexable cutting tool 1 can be positioned at any angle, the machining method of this embodiment can perform outer diameter machining of the workpiece W when the angle θ between the extension direction of the cutting insert 2 and the central axis O of the workpiece W is in the range of 90°<θ≦180°. For example, as shown in Figures 8 and 9, outer diameter machining can be performed by positioning the extension direction of the cutting insert 2 obliquely with respect to the central axis O of the workpiece W.

[0047] 8 and 9 are explanatory views showing another example of outer diameter machining using the indexable cutting tool 1. In FIG. The arrangement of the indexable cutting tool 1 shown in Figures 8 and 9 can also be easily adjusted by operating the drive mechanism 50 to rotate the holder body 31 by a predetermined angle around the rotation axis C. In the example shown in Figures 8 and 9, the angle θ between the extension direction (longitudinal direction) of the cutting insert 2 and the central axis O of the workpiece W is 130°.

[0048] With the indexable cutting tool 1 and workpiece W positioned as described above, the workpiece W can be rotated around its central axis O while the cutting insert 2 is moved parallel to the central axis O of the workpiece W, thereby turning the outer peripheral surface from the end of the workpiece W in the direction of the central axis O, thereby machining the outer diameter of the workpiece W.

[0049] As shown in Fig. 9, by setting the angle θ to 130°, the indexable cutting tool 1 can be positioned radially outward of the outer peripheral surface of the workpiece W. This makes it possible to suppress interference between the indexable cutting tool 1 and the workpiece W during outer diameter machining, and expands the range of outer diameter machining possible on the outer peripheral surface of the workpiece W. In addition, because the cutting insert 2 cuts obliquely into the outer peripheral surface of the workpiece W, the chips generated are thin and are easily broken even at high feed rates. Furthermore, because the direction in which the generated chips extend is toward the radially outer side of the workpiece W, contact between the chips and the workpiece W can be suppressed.

[0050] In order to obtain the above-mentioned effects, the angle θ formed between the extending direction of the cutting insert 2 and the central axis O of the workpiece W is preferably in the range of 110°≦θ≦140°. [Explanation of symbols]

[0051] 1, 100... Indexable cutting tools 2, 150...Cutting insert 3, 111...Holder 11... Fastening screw 20...Cutting part 21...Cutting edge 22...Scooping surface 23...flank 25...Holding part 25a...Pressed surface 25b...Seating surface 26, 151, 152...Breaker area 31...Holder body 31a...first end 31b…Second end 31c...Head attachment part 31d…Tip surface 32, 112...Head member 33...Head body 34...Head fixing plate 35...Insert mounting seat 35a...Pressing surface 35b...Base surface 35c...butt surface 36...Jaw 36A...Maxillary part 36B…Mandibular part 37...Relief section 38...Connection part 50...Drive mechanism C...Rotation axis H...Head protrusion direction O…Central axis W…Work material θ: Angle between the direction in which the cutting insert extends and the central axis O of the workpiece

Claims

1. a holder including: a head member having an insert mounting seat to which a cutting insert is attached; a holder body to which the head member is attached; and a drive mechanism that rotates the holder body about a rotation axis to change the attitude of the cutting insert; a rod-shaped cutting insert for groove machining held by the head member of the holder; Equipped with the head member has a pair of jaw portions that grip the cutting insert, and is fixed to the holder body in an attitude in which the directions in which the pair of jaw portions face each other are parallel to the rotation axis of the holder body; Indexable cutting tool.

2. the cutting insert has a rake face located on a side surface of an end portion of the cutting insert, a flank face continuing from the rake face and located on a tip end surface of the cutting insert, and a cutting edge located on an intersection ridge between the rake face and the flank face, The cutting insert is held by the head member with the rake face facing a tip side in a direction along the rotation axis of the holder body. The indexable cutting tool according to claim 1 .

3. 3. A turning method for cutting a workpiece using the indexable cutting tool according to claim 1 or 2, comprising: The indexable cutting tool is disposed relative to a columnar workpiece extending along a central axis in such a manner that a rotation axis of the holder body is perpendicular to the central axis of the workpiece; The outer diameter of the workpiece is machined in a range where an angle θ formed between the extending direction of the cutting insert and the central axis of the workpiece is 90°<θ≦180°. Turning method.

4. The outer diameter of the workpiece is machined within a range where the angle θ is 110°≦θ≦140°. The turning method according to claim 3.

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